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Impacts on the Earth

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A geohazard is a geological state that has the potential the cause extensive damage and danger. Such issues as volcanoes, earthquakes and landslides are classified as geohazards. South Australia has geohazards of its own. These are issues like coastal erosion, earthquake risk, flooding, landslides and bushfires.

"A bushfire is a fire that burns in grass or woodland and can threaten life, property and the environment." ( ACT Government, 2011)

Bushfires can originate from human activity and natural causes. Lightning is found to be the main source of ignition of a bushfire. Fires from human activity however cause more destruction, because they are usually located near populated areas.

The intensity of a bush fire is dependent on the availability of fuel, where it is located, rate at which it spreads and the temperature of the environment it is in. If the bushfire is found to spread quickly and widely, it is able to cause much damage and will be harder to control.

Many things fuel a fire. The most important is Oxygen. Australia's large open skies supply plenty of oxygen for a bushfire to blaze merrily. However bushfires are often fueled by the oil that is found in Eucalyptus leaves, and can easily burn up the dry plants that grow in Australia.
Location
The Australia environment is found to be dry; bushfires are able to easily spread. The more moist the surrounding flora is at the time of the fire, the less likely it is to burn. If a bushfire is prone to high wind, it can spread easily and cause much damage.
Temperature
A bushfire burns more heartily the hotter and drier the weather is. Hot temperature dries out the surrounding flora and also increases the intensity of the fire. On hot days, it is easy for a bushfire to break out.

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A geohazard is a geological state that has the potential the cause extensive damage and danger. Such issues as volcanoes, earthquakes and landslides are classified as geohazards. South Australia has geohazards of its own. These are issues like coastal erosion, earthquake risk, flooding, landslides and bushfires.

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The effects on Bushfires on the Earth's Spheres

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The effects on Bushfires on the Earth's Spheres

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Bushfire Geohazards

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5 unexpected ways that bushfires affect wildlife and ecosystems of forests

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5 unexpected ways that bushfires affect wildlife and ecosystems of forests

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Accuweather

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NSW Government

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Fire is often associated with negative impacts on the environment. We usually think of the damage and devastation fire causes to wildlife and vegetation, but a fire event can also be beneficial for our plants and animals.

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Impacts of Bushfires

Here we are considering the adverse effects of high intensity wildfires on the community and the environment. It should be remembered that it is not just intensity of a bushfire that matters. The extent of a bushfire is also very important. A large bushfire can cause multiple direct impacts: on life and property, on the survival of fauna populations, on water resources, and indirectly on government budgets and insurance costs. A large bushfire will also generate huge amounts of smoke.

Community Impacts

In severe fire seasons the damage caused by bushfires is astronomical. In the 2003 Canberra fire disaster, for example, the cost to insurers alone was $257 million (The West Australian, 13 Feb, 2003). The total cost of the fires, including the cost of suppression measures and lost productivity, would be much greater than this figure. Add to it the loss of life, personal trauma, loss of invaluable personal possessions and destruction of scientific equipment and data from the Mt Stromlo Observatory, and the ramifications of such disasters start to become apparent.
Part of a Canberra suburb burnt in 2003.
The community impacts from the 2009 Victorian disaster have been well documented in the media. An estimate of the final cost of this bushfire awaits the final report of the Royal Commission, but is likely to exceed a billion dollars.

And it does not end with the direct impacts of the fire on those affected. We all lose financially because the inevitable consequence of any large disaster is a rise in insurance premiums.

How much better then, if we can avoid, or at least minimise the risk, of such disasters happening again. While the Canberra fire disaster was a complex issue, with several factors contributing to the outcome, experienced fire managers have estimated that a prescribed burn costing about $100,000 would have prevented the disaster, but the burn did not take place due to mistaken land management policies. A mere $100,000 set against well over $257 million would seem a good deal for the community.

Canberra is not the only city to have suffered from bushfire damage in recent years. Sydney has experienced a series of lesser, but still serious, bushfire disasters since 1994. In some respects most Australian city fringes and country towns have become more prone to bushfire damage over the past 30 or so years, with the proliferation of rural lifestyle smallholdings and natural vegetation reserves that are preserved, rather than actively managed. Many people who move into rural smallholdings have little awareness of bushfire issues and the threat posed by unmanaged native vegetation.

The 2003 Canberra disaster and the Sydney fires were dwarfed by a succession of large wildfires in Victoria. There were very severe and extensive bushfires in Victoria in 2004 and 2007. The 2007 fires burned for several weeks and covered an area of about one million hectares. A recent unofficial estimate of the costs, which includes the damage to forests and property, as well as the costs of suppression, is over $900 million. With those sorts of losses, one might expect the State government to review its whole approach to bush fire management.

In fact, an inquiry was carried out mid-2007, and the Bush Fire Front made a submission to it. The report of this inquiry recommended a greatly enhanced program of fuel reduction burning in Victorian forests. Almost nothing had been done to implement this recommendation before the incredible disaster of February 2009. The full story awaits the outcome of the subsequent Royal Commission.

The 2016 fire disaster at Yarloop virtually destroyed the town and two lives were lost. A little earlier, more lives were lost in the Esperance fire. Two years after Yarloop, local people were still suffering trauma distress from the fire. Quite apart from the economic losses to individuals, the dislocation to people's lives is tremendous.

Public infrastructure also suffers in major wildfires, Bridges may be burnt, powerlines damaged and industrial plants destroyed. All these lead to diversion of Government resources to repair them, or to reduced economic performance by industry. Apart from the inconvenience of interrupted access, lack of electrical power and economic activity, job losses are frequently added to human woes.

As an example of infrastructure losses, after the 2016 Yarloop fire, in which over 160 homes were destroyed, Western Power estimated that the cost of restoring the electricity network at $26 million. Where does the finance for this come from? Probably from our pockets as Western Power recovers its losses through its tariffs.

Firefighters

Firefighting is inherently a dangerous business, especially when confronted with a fire like that shown below. While good training can minimise the risks, under "blow up" conditions like that in Victoria in February 2009, even experienced firefighters are at very high risk.

We should not forget that most people fighting rural fires are volunteers, who take on these tasks out of a sense of community spirit. Why should we expose them to the huge risks entailed in fighting fires in heavy fuels. Don't we owe it to them to make their job as safe as we can? Fuel reduction burning is the only practical way to do that.

Impacts on Forests

Forests

Of course, the forests incinerated by these intense bushfires also suffer great damage. Unlike the usual description employed in the media, most native forests are not "destroyed" by wildfire. Some are. Ash-type eucalypt forests are killed in this way, as the 1939 Victorian fire disaster clearly demonstrated. Drier forest types, such as jarrah in WA are not destroyed, although they are severely damaged and many trees are killed by high intensity bushfires.
Jarrah forest defoliated by a bushfire
Although some individual trees may die, the forest cover is not removed in a wildfire. In a large bushfire, however, the total number of trees killed can be very large. In the 2005 Perth Hills fire, for example, it was estimated that over 1.5 million trees were killed outright. As the image above shows, the forest environment, so important for so many aspects of biodiversity, is completely lost for some time, until the trees are able to reform their crowns.

Most eucalypts have a number of specialised features that enable recovery from intense fires. The remaining trees are, however, damaged in a number of ways. The cambium (the growth layer under the bark) may be killed in one side of the bole, resulting in "dry sides" which are subsequently prone to insect attack, degrading the timber for almost any use. Rots also gain entry via dry sides and burnt limbs. Trees that already have "hollow butts" will often burn out completely and fall, and new hollow butts will be created when a dry log burns alongside a standing tree. The upper parts of saplings and small trees are often killed so that the stems become malformed, thus reducing their potential commercial value, as well as permitting access by damaging fungi and insects.

These two images show bushfires cause hollow butts.

In 2003 there was a 25,000 ha wildfire at Mount Cooke, in the northern Jarrah forest, where post-fire evaluations were carried out. The fuel in most of the fire area was about 17 years old, carrying about 18 tonnes/ha of fuel. It was almost completely burnt out by a crown fire, and areas of bushland on Mt Cooke itself, regarded as fire refugia as they had not been burnt during three rotations of previous prescribed burning, were completely burnt-out by the high intensity fire. The photograph below shows the fire steaming up Mt Cooke, obliterating all in its path.

A post fire evaluation estimated that the fire had killed about 10 million of the overstorey trees outright. 10 million!! Whereas there had been multiple seral stages across the fire area before 2003, the fire reduced the whole area to one simplified seral stage.

In the case of pine plantations, on which we are now so dependent for timber supplies in WA, the trees are killed by high intensity bushfires. The logs may also be degraded for certain end uses by charcoal. Destruction of immature plantations disrupts the flow of future timber supplies, with adverse impacts on local employment. In blue gum plantations, we can expect that high intensity fires will kill most trees and, due to their small size, the degradation of logs by charcoal will render them useless for pulpwood, their intended market.
A burning pine forest
Wildlife

Intense bushfires cause the death, by incineration or smoke suffocation, of large numbers of native animals and insects that are unable to avoid the flames. Microsites (i.e. small areas of different nature from the general area) that do not burn under low intensity burns are incinerated and there are thus no refugial areas left for fire sensitive flora or fauna, or for subsequent recolonisation after the fire. Any animals that are able to take refuge in holes in the ground or in logs are usually quickly lost after a bushfire as they no longer have any cover from predators.

By contrast a mild fuel reduction burn causes very little damage. The usual objective is to burn only about 70% of an area, so that there is a patchwork of small areas unburnt in which insects and animals take refuge and from which later move out to recolonise the surrounding regenerating area. Unburnt plants in these patches also seed into adjacent areas. The fire also stimulates the germination of many species from seed stored in the soil. Other species of understorey plants regrow rapidly from rootstocks.
Quokka killed by a wildfire
The large areal extent of severe bushfires means that, unlike low intensity fuel reduction burning where any fauna losses are quickly made up from surrounding unburnt forest, there are wholesale fauna losses. The potential for total loss of a rare and endangered species is clear.
A ringtail possum caught in a bushfire.
The larger native fauna generally outrun a wildfire, but sometimes even they are caught.

It is not only terrestrial fauna that is adversely affected by bushfires. If extensive areas of a catchment are covered by a bushfire, the aquatic fauna is also affected, as shown by the study reported by Batini and Barrett.

[Click on About Fire > Wider Catchment Impacts to see a paper By F Batini and K Barrett on the wider impacts of the 2005 Perth Hills bushfire]

Impacts on Water Catchments

High intensity wildfires have very adverse effects on water supply catchments. The immediate impact is a great increase in runoff from the next rainy period, due to the lack of interception by tree and understorey foliage. While this may appear to be a benefit for dam storage, in fact it is not, as it is accompanied by extensive soil erosion and the transport of large quantities of silt and ash into the water storage facility. A bushfire like this....

produces this .........

Removal of the tree canopy exposes the soil to erosion with loss of soil fertility and wash of silt into dams. The ash is also highly detrimental to water quality and can actually cause a dam to be withdrawn from the supply system. This happened in Canberra after the 2003 fire disaster there. The silt and ash flow can also damage or even destroy valuable stream gauging stations (see the paper presented by Colin Terry at the Eaton Seminar in the Resources section)

In the large Perth Hills bush fire of 2005, monitoring of a Water Corporation experimental catchment showed that water yield increased by a factor of 2.2 times in the first year, but then returned to normal afterward, However, over 350 cubic metres of soil were deposited in the stream bed, silting up the stream and small pools. Large amounts of silt and ash passed through into the Mundaring Weir. A survey by the Department of Environment and Conservation found that aquatic diversity was significantly impaired in the wild fire area. Invertebrates in the wildfire area were also much less diverse than those from areas that had been covered by a low intensity fuel reduction burn.

It was estimated that between 1.5 and 2.3 million trees were killed outright by this high intensity bushfire. The forest has therefore been significantly degraded by this one wild fire. It will take many, many years to replace these trees.

Analysis by the Water Corporation of fuel reduction burn data and water flow over a 40 year period (1960-1999) showed a stream flow increase of between 20-49% for two years after each burn, As most burning is carried out in spring, when the stream zone is moist, there is minimal damage to vegetation and water quality. On the Gnangara Mound, recharge to the water table increased for 5 years after a fuel reduction burn.

In view of the great importance of the forested catchments in the Darling Range and the Gnangara Mound to metropolitan water supplies, it is imperative that high intensity wildfires be excluded from the region. It is so important that this happen that the management priority for the region should be reviewed and catchment protection be given higher priority than the current DEC/PAW/DBCA top priority for biodiversity protection. The entire area covered by the harnessed catchments or groundwater areas needs to be managed on a 5-7 year burning rotation.

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Here we are considering the adverse effects of high intensity wildfires on the community and the environment. It should be remembered that it is not just intensity of a bushfire that matters. The extent of a bushfire is also very important.

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For a bushfire to start there needs to be fuel, in the form of leaves and/or wood and a ignition or flame point.

This ignition can be caused either naturally by a lightning strike, spontaneous combustion or a deliberate/accidental flame.

Australian Bushfires are particularly severe as eucalyptus tree leaves contain large amounts of oil that act much like any oil and burn very fast and hot.

So how does a house burn down in a bushfire even if there are no trees are directly touching the house?
Three main reasons:

The water pressure at the local tap is too low for fire fighters to do anything.

Wind can send flying embers from the main fire which catch in gutters and ignite leaves or other materials around the house.

Gas lines leak and may explode.

Other tips for protecting your House

1. people should avoid living in or too close to the bush.

2. avoid planting tall eucalypts near their houses

3. reduce fuel load - get rid of leaves, fallen bark, dry wood around houses

4. plant deciduous trees around the house rather than native trees

5. ensure gutterings are clear of dry vegetation.

Thanks to Kath O'Brian for this

So, remember to keep your property clear of leaves if possible.
How do bush fires progress?
There are several major factors that affect the progress of a bushfire

high winds (provide more oxygen)

amount of fuel( eg leaves)

low humidity

All these contribute to the way a bushfire progresses. These factors then combine with the terrain.

The kind of terrain, eg hills and slopes, for example fires tend to spread faster up sides of hills.

Additionally flying burning embers of a main fire front can set spot fires ahead. The fire basically basically leaps ahead of itself helped by the wind.
How are plants and animals affected by bushfires?
Plants, typically their leaves and bark, burn but many plants are adapted to regrow. Though it sometimes depends on how hot the fire is.

A detailed article on plant ecology and biodiveristy of how plants are affected, in some cases benefit from bushfires...Australian National Botanical Gardens

Animals have a much harder time. The only animal able to properly survive are wombats that dig under the ground. Many animals die from smoke or are burnt.

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For a bushfire to start there needs to be fuel, in the form of leaves and/or wood and a ignition or flame point. This ignition can be caused either naturally by a lightning strike, spontaneous combustion or a deliberate/accidental flame.

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Dr Rachael Nolan

University of Technology, Sydney

Essentials

Fire has three essential requirements: fuel, heat and oxygen. Deprive it of any one of these and it will go out.

Different types of bushfire fuel (vegetation) burn differently: finer fuels like grasses burn more quickly, while more substantial, woodier fuels burn with greater intensity.

A bushfire will occur when there is sufficient dry fuel to burn, weather conditions are hot, dry and windy, and there is a source of ignition, such as lightning.

People living in fire-prone areas must prepare a bushfire survival plan and be ready to carry it out.

Much of the Australian bush has been shaped by bushfires, with some plants requiring intermittent burning to complete their life cycles.

They can start with just a spark and can burn for months, affecting landscapes and lives for years.

Bushfires are a natural, essential and complex part of the Australian environment and have been for thousands of years. Our country's first inhabitants lived seemingly hand in hand with fire, having developed complex fire management practices that complemented their deep understanding of the country and landscape in which they lived. Our ecosystems have evolved to be fire dependent, and require the periodic presence of fire. Herein lies the complexity: Australia is a land of fire where people have chosen to live.

Since European settlement, bushfires have been an event to be endured, a natural disaster with sometimes catastrophic effects. Research efforts have focused on how to predict and control bushfires in order to best protect lives and infrastructure, as well as understand the role that fire plays in the Australian landscape.

A bushfire approaching properties in Coonabarabran. Image source: Alex King, NSW Rural Fire Service. Used with permission.

How does fire work?

What actually makes a fire burn?

We all know that if you gather up a bunch of dry twigs, grass and leaves and put a lit match to them, they'll burn. Add some more sticks and bigger bits of wood and you've got a raging fire, ready for marshmallows. But why? How does fire actually work?

Fire is the result of applying enough heat to a fuel source, when you've got a whole lot of oxygen around. As the atoms in the fuel heat up, they begin to vibrate until they break free of the bonds holding them together and are released as volatile gases. These gases react with oxygen in the surrounding atmosphere. This chemical reaction causes a lot of heat, so much heat, in fact, that it can keep driving the reaction-as long as there's enough fuel and oxygen still present, the reaction will become self sustaining. The actual flames of the fire are the release of some of the heat energy as light.

These components have led to the development of the 'fire triangle' of fuel, oxygen and heat. Remove any one of these and fire cannot sustain itself.

For fire to continue burning, it needs oxygen, heat, and fuel-the three components of the "fire triangle". Remove one of these components to put out the fire.

And why does water put it out?

The primary role water plays in putting out a bushfire is cooling it down so there's no longer enough heat to sustain the fire. When you pour water onto a fire, the heat of the fire causes the water to heat up and turn into steam. This is a very energy-intensive reaction, and it sucks away the heat (which is a form of energy) of the fire. This leaves the fire without enough energy to keep burning.

Less significant is the role water can play in 'smothering' a fire, depriving it of the oxygen that it also needs to burn.

Predicting bushfires

Predicting when and where bushfires are likely to occur is obviously an important and useful part of bushfire management. It will be particularly important across many parts of Australia where the number of days of extreme fire danger are projected to increase under climate change.

Current thinking around predicting bushfires incorporates four 'switches' which all need to be 'on' for a fire to occur.

Fuel to burn

The Australian bush, though it has a reputation for being dry and scrubby, varies greatly from place to place around the country. There are regions of open woodlands, grassland savannas, dense rainforest. A bushfire will burn anything that it finds in its path, but different types of vegetation burn differently. Generally, fuel is classified as being fine (grasses and twigs that are less than 6 millimetres in diameter) or heavy (branches, logs or stumps). Finer fuels burn more easily, feeding the spread of the fire, but heavier fuels burn with greater intensity, creating more heat and making the fire more difficult to put out.

Fuel loads accumulate in different types of vegetation at different rates. In Western Australia, jarrah ( Eucalyptus marginata) forests build up fuel at a rate of around 1-2 tonnes per hectare per year, while karri ( Eucalyptus diversicolor) forests accumulate around 3-4 tonnes of fuel per hectare per year.

Dryness of fuel

Another key factor is fuel moisture, or how dry the bush is. The drier the fuel, the more easily it will burn. Fuel fits into two main categories: live and dead. Live fuels contain moisture that is regulated by the plants' physiology as well as the amount of recent rainfall. Dead fuel's moisture content tends to reflect the atmospheric moisture content-the relative humidity and level of moisture in the soil. These depend on recent rainfall and temperatures.

Researchers are developing methods of using remote sensing data from satellites or aircraft to detect the relative dryness of the bush. One way satellites can estimate fuel moisture is by picking up changes in the greenness of vegetation, an indicator of vegetation dryness. This is particularly important in grasslands. The key controls on the dryness level in fine fuels are relative humidity, temperature and recent rainfall.

Weather conditions

Certain weather conditions fuel a fire and help it burn. Long-term seasonal weather patterns, such as periods of drought or rainfall, can affect the availability and moisture content of vegetation and the fuel available for a fire to burn. A fire is much more likely to ignite, and continue to burn, in hot, dry and windy weather.

Source of ignition

Lightning strikes can provide the initial spark that sets off a bushfire, and cause around half of Australia's bushfires. Other causes can be faulty electrical wires, a cigarette carelessly tossed out of a car window, a hazard reduction burn gone wrong, arson, or accidental igniton.

Even a small spark has the potential to become a ferocious blaze. Image source: NSW Rural Fire Service. Used with permission.

Bushfire behaviour

The primary influences upon how bushfires move through the landscape are humidity, geography, wind and temperature.

Humidity and temperature

The effects of ambient temperature and humidity on a fire are pretty obvious. The hotter the air temperature, the closer any fuel is to its ignition point, and dry fuel will burn more easily. The lower the humidity, the drier the air is, again helping fuels burn as they release their moisture into the air more readily.

Slope of the land

The slope of the landscape is also important. Just consider a match and how much faster it burns when you hold it so that flame is burning up the stick (and towards your fingers!) than down. Similarly, fires burn much faster uphill than down. This is because the radiation and convection a fires creates preheat the fuel source, and this is much more readily done upslope than down. A 10-degree increase in slope usually results in a doubling of the speed of the fire. Fire will spread up a 20-degree slope four times as fast as it will along flat ground.

How wind spreads fire

Generally, as long as wind speeds are below 12-15 km/h, a fire will burn slowly. However, if wind speeds are even slightly higher than this, they will have a significant impact on the fire movement. A change in wind, often from a cold front, can activate the side of a fire, making it broader. In general, a wider fire will burn faster than a very narrow one.

Fires also create their own weather; the heat of a fire can result in whirlwinds and turbulent air currents. These can drive the fire sideways, broadening the fire front. Wind can also cause spotting-carrying pieces of burning fuel, like twigs, leaves or small embers, ahead of the fire, igniting more small fires.

Fire intensity

Fire intensity is described in terms of the number of kilowatts of energy each metre of the fire front generates. A controlled hazard-reduction fire usually produces less than 500 kilowatts per metre of energy, while an extreme bushfire can generate more than 100,000 kilowatts per metre. Once a fire's intensity exceeds around 2,000 kilowatts per metre it can no longer be safely managed by firefighters working on the ground.

Computer models

A number of computer models have been developed to help predict the spread and shape of fires across the landscape. The most widely used of these is Phoenix Rapidfire, developed by the Bushfire CRC, the University of Melbourne and various fire agencies. Western Australian authorities used Aurora, a model developed by the University of Western Australia, Landgate and the Bushfire CRC, and CSIRO has developed a new model called Spark.

These models take into account all the factors discussed above that influence the behaviour and spread of the fire. They incorporate meteorological data as well as geographical landscape data like the slope of the land, vegetation type, and the presence of unburnable features like roads or water bodies. Phoenix Rapidfire also incorporates components that deal with spotting and fire suppression options.

When a fire becomes a firestorm

If a fire gains enough momentum, it generates so much heat that it creates its own wind currents, and becomes a raging inferno sometimes known as a firestorm. The fire's heat creates an extremely strong updraught of air. The air at ground level around the fire is then drawn in strongly towards the fire's centre to replace the rising air. The turbulence this creates can result in fire whirls which spiral and dart around, burning as they go.

The heat of the fire can cause thunderstorms or pyrocumulus clouds. These can produce lightning strikes, which can start new fires. With the right combination of atmospheric conditions, fire tornadoes can be created. These can have wind speeds of greater than 250 km/h and are extremely destructive.

Controlling a bushfire

A number of techniques are used to contain and extinguish bushfires. Smaller fires are fought directly, by firefighters applying water to the flames, either from the ground or the air. Fuel breaks can be created using hand tools such as rakes and hoes.

Another way to try and contain a fire is to deliberately burn sections of the fuel in its path, so that there's no flammable material left to fuel it. Because these small fires are intended to 'burn back' to the fire front, this process is known as 'backburning'. It's used to try and stop a fire in its tracks, and also to protect particular areas, such as houses or other infrastructure, by creating a fuel break between them and the fire front.

Water bombing is another method used to control large fires. We've seen the footage on the news of helicopters flying over raging fire fronts, tipping what look like small buckets of water onto the flames. To the untrained eye, it doesn't look all that effective. But the point of water bombing is not so much to douse the flames as to increase the humidity in the surrounding air. The water tipped out from the helicopter turns to steam, or water vapour, which makes it harder for the fire to continue burning.

Sometimes the water incorporates a gel which also helps put out the flames, or a chemical fire retardant, often dyed red so the areas where it's been dropped are clearly visible. The retardant inhibits the fire's ability to ignite fuels, and remains on the vegetation after water has evaporated.

Aeroplanes are also used to drop water or retardant on the fire. These can vary in size from relatively small to very large, such as the DC-10.

A helicopter dropping water on a bushfire. Image source: Wayne Rigg, Country Fire Authority. Used with permission.

Warning and survival

Being able to predict bushfires means we can more effectively warn people, prevent loss of life and avoid catastrophic damage to property and infrastructure.

Australia has a national fire danger rating system that was originally developed in the 1960s. It is based on weather conditions and local fuel loads. The Australian Bureau of Meteorology provides weather forecasts and fire weather warnings to both media agencies and local fire authorities to help inform their decisions about issuing fire danger ratings. Meteorologists are also directly involved with decision making on the ground.

The Victorian fire danger rating sign. Note that most of Australia uses 'Catastrophic' for its highest danger rating, rather than 'Code Red'. Image source: Nathan Maddock, Bushfire and Natural Hazards CRC. Used with permission.

Following the Black Saturday bushfires in Victoria in 2009, the states and territories modified the warning levels to include a higher level: Catastrophic (referred to as Code Red in Victoria). Current efforts are updating the science underpinning the danger rating system and developing a standardised fire danger rating system that will apply across the country.

Surviving a fire

Recent research has revealed some interesting information about how people lose their lives in bushfires. Most people were killed when out in the open, with nearly three-quarters of these within 200 metres of their home. Around one-third of all bushfire deaths occurred within a house, and these mostly occurred on days with Catastrophic (Code Red) fire conditions. More than 90 per cent of these deaths occurred in rooms that did not have a door leading outside.

The most important thing for people living in bushfire-prone areas to do is to create a survival plan, and to practise it.

The common advice from the various authorities is to be prepared, and to either leave early, or stay and defend. Prepare, Act, Survive is the nationally accepted approach.

An understanding of the risks of staying to defend a home during a bushfire, or evacuating to a safe place, is essential. All agencies agree that if you choose to leave, you should leave early, usually the day before, or before 10 am on the day of risk. If you choose to stay, you must be both physically and mentally prepared. Look at the information from the various sources above to find out how best to prepare yourself or your property for the risk of bushfire.

In terms of protecting yourself, one of the most dangerous aspects of a bushfire is the radiant heat it releases. At times, this heat can be so intense it can kill people who are quite far from the fire. The most effective protection from radiant heat is distance, or a solid barrier, like a wall or an embankment. Next best is covering up-putting on protective clothing like long pants and a shirt, or overalls made from natural fibres, not sythetics. The suits firefighters wear are not simply a fashion statement. Even a blanket is better than no protection.

Firefighters wearing protective clothing while undertaking a prescribed burn. Image source: David Bruce, Bushfire and Natural Hazards CRC. Used with permission.

Other risks are dehydration, smoke inhalation and heat stroke, which can cause people to lose consciousness. The fumes from burning materials, particularly houses or cars, can be toxic, and breathing them in can lead to disorientation or death. In many cases, the fumes are heavier than air so they sink to the lowest part of the landscape or building. This is one of the reasons why sheltering in a cellar or 'bunker' under a house is not recommended.

The effects of fire

Clearly, all fires have an effect on the ecosystem, and research is ongoing to determine both the negative and positive consequences of fire. In the Australian Alps, wildfires have a greater impact on Alpine Ash forests than managed fires. However, it's worth noting that a burn regime of less than 30 years could wipe out these forests. The Alpine Ash only produces seeds after it reaches maturity at an age of 30 years or more; fires occurring at a frequency of less than 30 years would therefore kill trees before they could produce seeds.

But there are also cases in which fires actually help plants regenerate. The survival of the Mountain Ash depends on the occurrence of fires. Mountain Ash can only regenerate from seeds, and fire is essential to provide the right conditions for their germination. However, if fires occur before the young trees reach maturity and produce seed (at 50 years old), the species may be completely wiped out. It may then be replaced by other species better adapted to that fire regime.

The survival of Mountain Ash (pictured) depends on the occurrence of fires. Image source: CSIRO Science Image.

Some plant species, such as eucalypts, regenerate from lignotubers, which are stimulated by fire to develop shoots. Also, smoke from plant material promotes seed germination in more than 400 species of Australian plants.

It's not just wildlife and plant species that can be affected by fire. Researchers at the University of Melbourne are exploring the effects of bushfires on water supply. Bushfires can have important consequences for water supply, by increasing erosion and dirtying water, making it unsafe to drink. Following some bushfires, townships have been forced to boil water to make it safe to drink. Along with a degradation of water quality, in some forests, particularly the Mountain Ash forests of Victoria, bushfires can reduce the amount of water available for drinking. This is because the forests use more water as they grow back after fire.

Australia's most devastating fires

Between 1900 and 2011, 866 people in Australia were killed by bushfires. The most destructive of these occurred fairly recently.

The Ash Wednesday bushfires of 16 February 1983 that swept through southern Victoria and South Australia were devastating. Seventy-five people lost their lives-47 in Victoria and 28 in South Australia. More than 300,000 hectares of land were burnt and 3,000 houses and other buildings were lost.

Aftermath of the 1983 Ash Wednesday bushfires. Seventy-five people died, 300,000 hectares of land were burnt and 3,000 buildings lost. Image source: Sydney Oats / Flickr.

Ten months of dry weather and a hot summer produced a dry landscape, primed for fire. Temperatures were in the high 30s to mid-40s, the air was dry and there were gale-force winds.

There were already 104 fires burning that Wednesday, but by the afternoon several more were burning throughout southern Victoria. It's not known exactly how all these fires started, but some were caused by powerlines clashing with each other and with trees. Some were deliberately lit.

The Ash Wednesday fires were the deadliest on record in Australia until the Black Saturday fires of February 2009.

Once again, there were hot, dry conditions, with extremely high temperatures and strong winds. On 7 February 2009, around 400 fires started in Victoria. Temperatures in the region reached the mid-40s and winds were stronger than 100 km/h. Around 12.30 pm, powerlines fell in Kilmore East, sparking a fire that went on to become a firestorm that devastated the communities of Kinglake, Strathewen and St Andrews.

Aftermath of the 2009 Black Saturday bushfires. One hundred and seventy-three people died, 445,000 hectares of land were burnt and 2,100 homes lost. Image source: Elizabeth Donoghue / Flickr.

Most fire activity occurred during the afternoon and early evening of Black Saturday. Although evening brought a cool change to the region, it was accompanied by winds stronger than 120 km/h. Burning a total area of around 445,000 hectares of land, the fires moved at an average speed of 12 km/h, with some fires travelling up to around 72 km/h. One hundred and seventy-three people were killed in the Black Saturday fires. More than 400 people were injured and 2,100 homes were lost.

The amount of energy released by the fires was estimated to be equivalent to around 1,500 Hiroshima atomic bombs. In some situations, the fires produced sufficient radiant heat to kill people 400 metres away.

A Royal Commission was established to examine the causes and consequences of the Black Saturday fires. Its final and interim reports are a valuable source of information on the impact of bushfires in Australia.

Bushfires and climate change

As described above, four things need to be in place for a bushfire to occur: fuel must be available; the fuel must be dry; weather conditions need to be hot, dry and windy; and there needs to be a source of ignition. So, is climate change likely to affect any of these?

As plants use carbon dioxide (CO ₂) from the atmosphere to generate their energy, it's possible that higher atmospheric CO ₂ concentrations will lead to enhanced plant growth in some areas. This is known as the CO ₂ fertilisation effect, and it will ultimately create more fuel for a potential fire. However, this effect only improves plant growth when there are sufficient amounts of other nutrients and water. Warmer temperatures at night and during winters will also increase the growing season of many plants.

The drier the fuel, the more likely it is to burn. Increased average temperatures caused by climate change will contribute to fuel dryness. Rainfall will also influence how dry (or wet) the fuel is. While the predictions for changes in rainfall are not as definitive as those for temperature, it is expected that there will be less rainfall in much of Australia in the future, particularly in the south-eastern and south-western regions.

The weather conditions are part of the criteria used to assess the degree of fire risk on any given day. An increase in warmer and drier weather means a higher number of days of high or extreme fire risk. Indeed, we've already seen an increase in high and extreme risk days in Australia over the past four decades. Along with more days of higher risk, climate change will also bring an extension of the fire season.

It is inevitable that Australia will always have large fires but, with better land management and improved understanding of bushfire behaviour, hopefully the catastrophic loss of life that has occurred in the past can be avoided.

More on bushfires: Managing landscapes

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Bushfires are a natural, essential and complex part of the Australian environment and have been for thousands of years.

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Australian Government

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What is a bushfire?

Bushfires and grassfires are common throughout Australia. Grassfires are fast moving, passing in five to ten seconds and smouldering for minutes. They have a low to medium intensity and primarily damage crops, livestock and farming infrastructure, such as fences. Bushfires are generally slower moving, but have a higher heat output. This means they pass in two to five minutes, but they can smoulder for days. Fire in the crown of the tree canopy can move rapidly.

Bushfires are an intrinsic part of Australia's environment. Natural ecosystems have evolved with fire, and the landscape, along with its biological diversity, has been shaped by both historic and recent fires. Many of Australia's native plants are fire prone and very combustible, while numerous species depend on fire to regenerate. Indigenous Australians have long used fire as a land management tool and it continues to be used to clear land for agricultural purposes and to protect properties from intense, uncontrolled fires.

Historically, bushfires have caused loss of life and significant damage to property. While naturally occurring bushfires cannot be averted, their consequences can be minimised by implementing mitigation strategies and reducing the potential impact to areas which are most vulnerable

What factors create a favourable environment for bushfires to occur?

The basic factors which determine whether a bushfire will occur include the presence of fuel, oxygen and an ignition source. The fire intensity and speed at which a bushfire spreads will depend on ambient temperature, fuel load, fuel moisture, wind speed and slope angle.

Fuel load

Fuel load describes the amount of fallen bark, leaf litter and small branches accumulating in the landscape. Generally speaking, the greater the fuel load, the hotter and more intense the fire. Fuel which is concentrated but loosely compacted will burn faster than heavily compacted or scattered fuel sources. Smaller pieces of fuel such as twigs, leaf litter and branches burn quickly, particularly when they are dry and loosely arranged and will burn quickly in the fire front. Larger fuels, such as tree trunks often burn later after the fire front has passed. The natural oil within eucalypt trees promotes the combustion of fuel.

Fuel moisture

Dry fuel will burn quickly, but damp or wet fuel may not burn at all. As a consequence, the time since rainfall and the amount of rain received is an important consideration in assessing bushfire danger. Often a measure of the drought factor, or moisture deficit, will be used as an indicator of extreme bushfire weather conditions.

Wind speed

Wind acts to drive a fire by blowing the flames into fresh fuel, bringing it to ignition point and providing a continuous supply of oxygen. Wind also promotes the rapid spread of fire by spotting, which is the ignition of new fires by burning embers lofted into the air by wind. Spotting can occur up to 30km downwind from the fire front.

There is a threshold wind speed of around 12 to 15km/h which makes a significant difference in the behaviour of bushfires in the open. When wind speeds are below this threshold, fires with heavy fuel loads burn slowly. However, even a slight increase in wind speed above this threshold results in a significant increase in fire behaviour and advancement. The width of a fire front also has an influence on the rate of spread and a wind shift can immediately widen the forward edge of a fire.

Ambient temperature

The higher the temperature the more likely it is that a fire will start or continue to burn. This is because the fuel is closer to its ignition point at high temperatures and pre-heated fuel loads burn faster.

Relative humidity

Dry air promotes a greater intensity fire than moist air. Plants become more flammable at a low humidity because they release their moisture more easily.

Slope angle

Fires pre-heat their fuel source through radiation and convection. As a result, fires accelerate when travelling uphill and decelerate travelling downhill. The steepness of the slope plays an important role in the rate of fire spread. The speed of a fire front advancing will double with every 10 degree increase in slope, so that on a 20 degree slope, its speed of advance is four times greater than on flat ground.

Ignition Source

Bushfires can originate from both human activity and natural causes with lightning the predominant natural source, accounting for about half of all ignitions in Australia. Fires of human origin currently account for the remainder and are classified as accidental or deliberate. Fires lit deliberately can be the result of arson or might be designed to achieve a beneficial outcome but conditions have changed, resulting in uncontrollable spread.

Unfortunately deliberate and accidentally lit fires are more prevalent near populated areas and have a disproportionately higher risk of infrastructure impact. Arsonists place people and property at serious and unnecessary risk, particularly when igniting fires on extreme fire weather days.

Where do bushfires occur?

The Australian climate is generally hot, dry and prone to drought. At any time of the year, some parts of Australia are prone to bushfires. The widely varied fire seasons are reflected in the continent's different weather patterns. For most of southern Australia, the danger period is summer and autumn. For New South Wales and southern Queensland, the peak risk usually occurs in spring and early summer. The Northern Territory experiences most of its fires in winter and spring.

Grassland fires frequently occur after good periods of rainfall which result in abundant growth that dries out in hot weather. Bushfires tend to occur when light and heavy fuel loads in Eucalypt forests have dried out, usually following periods of low rainfall.

The potential for extreme fire weather varies greatly throughout Australia, both in frequency and severity. When potential extreme fire weather is experienced close to populated areas, significant loss is possible. In terms of the total area burnt, the largest fires are in the Northern Territory and northern areas of Western Australia and Queensland. Most loss of life and economic damage occurs around the fringes of cities where homes are commonly in close proximity to flammable vegetation.

In the years between 1967 and 2013, major Australian bushfires have resulted in over 8000 injuries and 433 fatalities, close to 50 per cent of all deaths from major Australian natural disasters in the period (excluding heatwaves). Over this same period, bushfires cost approximately A$4.7 billion (2013 Australian dollars, including deaths and injuries but excluding most indirect losses).

A fire front advances more quickly when travelling upslope and slows travelling down slope. The speed of a fire front advancing will double for every 10 degree increase in slope, so that on a 20 degree slope, its speed is four times greater than over flat ground.

References:

Ladds M, Keating A, Handmer J and Magee L (2017)How much do disasters cost? A comparison of disaster cost estimates in Australia. International J of DRR. 10.1016/j.ijdrr.2017.01.004

Ladds, MA, Magee, L, Handmer, J (2015) AUS:DIS - Database of losses from disasters in Australia 1967-2013. https://github.com/liammagee/sealand

John Handmer, Monique Ladds and Liam Magee (December 2016), Disaster losses from natural hazards in Australia, 1967-2013. (Report with AGD)

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Geoscience Australia is the national public sector geoscience organisation. Its mission is to be the trusted source of information on Australia's geology and geography to inform government, industry and community decision-making. The work of Geoscience Australia covers the Australian landmass, marine jurisdiction and territories in Antarctica.

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Although thousands of trees, shrubs and grasses are destroyed by bushfire, many plants will regrow.

Some plants are protected from the heat of the flames by thick bark. Some have buds under the bark that grow after a fire, fed by food stored in the bark and water collected by roots deep in the soil. The seeds of some cedar plants are fire resistant. They fall into the ash of a fire and when rain falls, they begin to grow. Some plants protect their buds from fire with layers of succulent foliage or a cluster of needles.

Australian Bushfires 2019 - 2020

To date (January 20, 2020) more than 10.7 million hectares of Australian land have been burned. At least 29 people have died and over 2,000 homes and other buildings lost.

NSW has declared a state of emergency and Victoria a state of disaster, and major fires are raging in South Australia and Western Australia.

And while forest trees burn, Australia's wildlife also suffers.

It's been estimated that around 1.25 billion animals have been killed across Australia to date. This includes thousands of koalas, kangaroos, wallabies, kookaburras, cockatoos and honeyeaters burnt alive, and many thousands more injured and homeless.

These animals habitat has been destroyed and even if they are lucky to survive, many will have nowhere to live and nothing to eat.

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Although thousands of trees, shrubs and grasses are destroyed by bushfire, many plants will regrow. Some plants are protected from the heat of the flames by thick bark. Some have buds under the bark that grow after a fire, fed by food stored in the bark and water collected by roots deep in the soil.

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The Conversation

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This summer's bushfires have destroyed homes, precious ecosystems and, tragically, lives. Fires in South Australia and Western Australia killed two and six people, respectively. On Christmas Day more than 100 properties were destroyed in Victoria, and ongoing fires in Tasmania's wilderness have claimed ancient, fire-sensitive vegetation.

Our key strategy to address this is to evacuate fire-prone areas extensively on days when fire weather is likely to present a risk. In essence, we are leaving our homes to fend for themselves, and rightly so. Homes can be replaced; lives cannot.

We know the cost of fire. In a warming world, it is very likely we will see more frequent and more extreme fires. To adapt to these future fires we will need to change how we approach fire management and the safety of our homes.

Fortunately there are good examples in contemporary Australia of how we might do so.

Land of fire

Before European settlement, Australia was a fire-adapted continent from the southern tip of Tasmania to the tropical north.

Its indigenous citizens understood fire both as a threat and as a tool. Indigenous people regularly used fire to modify the vegetation so that fires could not reach an intensity that would damage to trees, animals or indigenous settlements.

Unfortunately, most of Australia looks nothing like it did back then. The bush in many parts has reverted to a thick impenetrable scrub with fuel loads that can support fires so severe that agencies have no way of stopping them.

On Black Saturday in 2009 173 people were killed in Victoria. But of the 400 fires that started, only a handful could not be stopped by fire agencies, and it was these fires that caused most of the destruction.

The key reason that fire agencies are overwhelmed is a combination of weather and ignition circumstances. Crews and aerial support scramble to reach fires that have started in remote locations before they rapidly develop to a size where it can no longer be stopped. In catastrophic conditions such as those on Black Saturday this need only be a fire of about one hectare.

We can assess the severity of a fire using the Forest Fire Danger Index (or FFDI). The FFDI is a measure of weather factors and is the basis of the national fire danger rating system. Fires running with an FFDI higher than 50 cannot be safely suppressed by fire agencies in a forest. Fires under these circumstances represent over 90% of our life and house loss.

Learning from indigenous experts

In a recent documentary produced by SBS Insight, Line of Fire, I joined indigenous fire practitioner Victor Steffenson to discuss traditional fire management. Victor regularly visits communities from Victoria to Western Australia and as far north as Cape York to pass on what he has learned from his elders.

"We live in a country that needs fire, and what has happened is that we have stopped evolving with fire," he said.

"If we're going to deal with fire as a nation, we need to empower the communities that live in those regions to be able to put the right [fire] management in place.

"And so teaching how you can burn where fire behaves like water and trickles through the country and it doesn't burn everything."

But most of us have a major problem with this concept. We have grown accustomed to the idea that fire should be excluded from our landscape, except when it is " prescribed " to reduce fuel.

We have made our houses out of combustible materials and surrounded them with more combustible things, and interestingly, the thought of having even a low intensity fire spread onto our properties would immediately have us reaching for the phone to call our insurance provider.

When did things start going wrong? Well, pretty much from the start of mass urbanisation. Our builders replicated houses from their country of origin, fenced the landscape (with fences that needed to be replaced after fire) and built open sheds full of items that could easily burn. Fire was no longer welcome on the landscape.

Living with fire

How do we change our ways of thinking to embrace fire a useful tool and accepting that it is an inevitable process and an integral part of our landscape?

We need to rethink our bushfire planning regulations by focusing on the fuel loads under the trees rather than the trees themselves.

We also need to rethink our bushfore building reguations. The current Australian standard for buildings in bushfire prone areas - AS3959 - seeks to protect a combustible home with a fireproof facade. Instead we need to build our homes entirely from non-combustible materials as is described in a new building standard from the National Association of Steel Framed Housing.

By focusing on combustibility we can ensure our houses are completely resistant to the arrival of embers and low intensity fire. Expensive materials that are highly resistant to fire are not needed because intense fires are managed in the landscape. By striking a balance like this we can achieve a flexible low cost outcome for those living in bushfire prone areas.

For example, for our communities in the far north, fire is a yearly occurrence (in savanna grasslands). The people living next to these grasslands have an intrinsic knowledge of fire. Rather than having continuous grass against their houses they maintain a buffer either by using fire or other means.

If we focus on building houses and landscapes that cannot be damaged by low intensity fire, we will then be able to invite regular "cool burning" fires back into the landscape - including our back yards.

In so doing, fuel loads will not reach a level that will bring intense fire to our houses, even under " code red " weather conditions. Our houses would no longer require extensive provisions to resist intense radiant heat or being engulfed by flames.

The regular use of fire as management tool by our communities and incorporating indigenous knowledge in our fire management practices would present a key opportunity to create and pass on knowledge and understanding throughout different generations.
The Line of Fire will be featured on SBS Insight on Tuesday night.

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Adapting to bushfires: a new idea of 'fire-proof' homes

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This summer's bushfires have destroyed homes, precious ecosystems and, tragically, lives. Fires in South Australia and Western Australia killed two and six people, respectively. On Christmas Day more than 100 properties were destroyed in Victoria, and ongoing fires in Tasmania's wilderness have claimed ancient, fire-sensitive vegetation.

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Link to lots of ABC movies about bushfires

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Education resources for schools teachers and students - ABC Education

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ABC Education has 5000+ educational games, videos and teaching resources for schools and students. Free Primary and Secondary resources covering history, science, English, maths and more

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Megafires and the survival of the Alpine Ash

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Megafires and the survival of the Alpine Ash

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ABC movie

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Education resources for schools teachers and students - ABC Education

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ABC Education has 5000+ educational games, videos and teaching resources for schools and students. Free Primary and Secondary resources covering history, science, English, maths and more

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Volcanoes are considered one of the most destructive natural disasters of Earth. These formations are opened mountains filled with lava and hot gases under the earth's surface. After reaching a certain pressure, volcanic eruptions occur that have dangerous outcomes causing tsunami, earthquakes and mudflows. Everything that crosses a lava stream is demolished. Life around such volcanoes is barely possible.

Life Around Volcanoes

Living near an active volcano can be hazardous, yet favorable. Some volcanic products are vital and the soil is rich. It attracts life. When a volcano erupts, the gas and the lava rupture any form of life to ashes. But when the lava cools, the lush soil left behind lets various species of plants grow. This vegetation attracts animals. Rain helps the eruption cool off. Within a span of three years, plants and animals can be found resettling in the area again.

Land Animals

Animals naturally sense disasters much before humans. This internal warning allows them to sense tremors and pressure in the earth's surface even before volcanic outbreaks activate. Therefore, many animals are able to escape from an area before the eruption occurs. However, those who don't escape are killed by the volcanic lava. The volcanic soil that encourages plant growth and herbivore animals also ultimately attracts carnivorous predators.

Marine Life

In "Volcanoes Around the World," Jen Green states that as soon as the eruptions cease, plants and animals begin to establish again. To study the effect of an underwater volcano on marine life, scientists are paying close attention to the volcano in Guam, which has been very active and has shown a dramatic increase in size since it was discovered in 2004. The marine life near this volcano includes varieties of fish, shrimp, crabs and limpets uncommon from the normal marine life. These species thrive in warm water that also has strong chemicals. Two new species of shrimps, known as the harvester (gazing on the bacterial rocks) and hunter shrimp (predator with claws), which are not found in marine life have been discovered thriving in the area.

Concerns

In "Principles of Animal Physiology," Christopher D. Moyes states that many anatomical adaptations allow animals to survive at high sulfide concentration areas. After volcanic activity, these changes are necessary for the survival of their species. Although toxic gases emitted from these volcanoes damage the life forms surrounding it and pollute the land and water, millions of people reside near volcanoes and wildlife still flourishes. Biodiversity exists even around an active or dormant volcano.

References

"Volcanoes Around the World'; Jen Green; 2009

"Volcanic Hazards in Central America"; William Ingersoll Rose; 2006

"Principles of Animal Physiology"; Christopher D. Moyes and Patricia M. Schulte; 2007

Photo Credits

Stockbyte/Stockbyte/Getty Images

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Volcanoes are considered one of the most destructive natural disasters of Earth. These formations are opened mountains filled with lava and hot gases under the earth's surface. After reaching a certain pressure, volcanic eruptions occur that have dangerous outcomes causing tsunami, earthquakes and mudflows.

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How do Volcanoes affect plants and animals

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How do Volcanoes affect plants and animals

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How Do Volcanoes Affect Plants & Animals?

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Predicting Chaos

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How volcanologists brave lung-singeing fumes to monitor eruptions with cutting-edge sensors

smithsonianmag.com

Volcanoes have blindsided humans for millennia, leaving entire cities at the whim of their devastating eruptions. But compared to other forms of natural disaster, volcanoes actually offer a variety of quiet clues leading up to their destruction. Now, new developments in volcano monitoring systems allow scientists to sniff out, forecast and plan for eruptions with more precision than ever before.

"We are now able to put really precise instruments on volcanoes to monitor the types of gases that are emitted, and that gives us a clue as to where magma is in the system," says Marie Edmonds, a volcanologist at the University of Cambridge who has been working amongst fuming volcanoes for about 15 years. "We can see trends in the data relating to eruptions that are just about to happen."

Edmonds is part of an international group called the Deep Carbon Observatory that is working to place newly developed gas sensors on 15 of the 150 most active volcanoes on Earth by 2019, to improve their capacity to forecast different types of eruptions worldwide. Last week the Deep Carbon Observatory released an interactive visualization, supported in part by the Smithsonian Institution's Global Volcanism Program, that allows the public to watch visualizations of historic volcanic data evolve through time.

The visualization also lets viewers follow along as new sensors are deployed. These sensors continuously measure carbon dioxide, sulfur dioxide and water vapor fuming out of volcanoes, and are placed within large boxes and buried underground with antennae on the surface. In recent years, advancements in electronics have made them more precise and affordable, allowing scientists to use them more prevalently around he world.

Yet placing these sensors on top of active volcanoes isn't without risk. Researchers must wear reflective suits to protect their skin from excess heat, and gas masks to protect their lungs from getting singed by corrosive gases-sometimes after hiking long distances through remote regions to reach a site. But Edmond says the potential good such work can do for populations at risk makes the more dangerous parts of the job worthwhile.

"It's brilliant to know that you are doing something to actually help people," says Edmonds. "You do think about what you're doing because it is sometimes dangerous, but I really do enjoy it."

In the past month, researchers from Edmonds' team attached one of their sensors on a drone and measured emissions from a remote volcano in Papau New Guinea over a short period of time, demonstrating another recently-developed technique used to collect snapshots of volcanic activity. When collected over a range of different types of volcanoes, these snapshots help scientists better understand the complexities of the activities leading up to an eruption. (What drones can't do, however, is take long-term measurements.)

Gas sensors help forecast eruptions because, as magma rises up, the resulting release of pressure overhead uncorks gases dissolved within the magma. Carbon dioxide billows out relatively early on and, as magma slithers higher up, sulfur dioxide begins to fume out. Researchers use the ratio of these two gases to determine how close the magma is getting to the earth's surface, and how imminent an eruption may be.

As magma rises, it also pushes through rock in the crust and causes tiny earthquakes not usually felt by humans above, but detectable with sensitive seismic equipment. Edmonds' team often pairs gas sensors with seismic stations and uses the data in tandem to study volcanoes

Robin Matoza, a researcher at the University of California at Santa Barbara who is not involved in Edmond's research, agrees that technological advancements in recent years have drastically improved researchers' ability to understand the inner workings of volcanoes and the behaviors leading up to eruptions. In places where his team once had just a few seismic stations, they can have now installed 10 or more due to the smaller size and increasing affordability of the technology. The ability to compute the collected data has also improved in recent years, Matoza says.

"Now we are easily able to store years worth of seismic data just on a small flash drive," says Matoza, who studies seismic signals released by volcanoes prior to eruptions. "So we can easily query that large data and learn more about the processes contained in it."

To supplement gas and seismic information on a broader scale, researchers use satellites to study eruptions from above. Volcanologists at the Alaska Volcano Observatory in Anchorage and Fairbanks collect this suite of gas, seismic and satellite data to on a regular basis, monitoring roughly 25 volcanoes across the state and offer early warnings to residents.

For example, they released a series of warnings in the months leading up to the 2009 eruption of Mount Redbout, about 110 miles (180 km) southwest of Anchorage. They also work closely with the Federal Aviation Administration to help detect aviation hazards during eruptions.

Over time, the researchers agree that satellites will become increasingly useful in collecting data over large regions. But at the moment, satellites are less precise and not as reliable as the other tools, in part because they don't collect data as rapidly and don't function well during cloudy weather.

"You can have a satellite pass over a volcano and it can be obscured by clouds," says Matt Haney, a volcanologist at the Alaska Volcano Observatory. "I imagine in the future there will be new satellites that are launched that will be even more powerful."

Despite the challenges of this work, Edmonds says it can be easier to forecast volcanic eruptions than some other hazards because of the array of warning signs preceding eruptions compared to certain earthquakes and other abrupt disasters. And while the researchers may not be able to forecast to the exact day or hour that an eruption will occur yet, rapidly advancing technology is moving them in that direction.

"The more instruments and the more sensors just contribute to our toolbox," says Edmonds. "We are one step closer."

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Predicting Chaos: New Sensors Sniff Out Volcanic Eruptions Before They Happen

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smithsonianmag.com Volcanoes have blindsided humans for millennia, leaving entire cities at the whim of their devastating eruptions. But compared to other forms of natural disaster, volcanoes actually offer a variety of quiet clues leading up to their destruction. Now, new developments in volcano monitoring systems allow scientists to sniff out, forecast and plan for eruptions with more precision than ever before.

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Newspaper article

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Document

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Good information

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Impact on Ecosystems movie

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Education resources for schools teachers and students - ABC Education

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ABC Education has 5000+ educational games, videos and teaching resources for schools and students. Free Primary and Secondary resources covering history, science, English, maths and more

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What is Drought and How Long Does it last?

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What is Drought and How Long Does it last?

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Kidsnews

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Much of eastern and southeastern Australia is in what many are calling the worst drought in living memory for periods ranging from one year to seven years.

National Farmers' Federation* president Fiona Simson said rain had been "pretty much non-existent" this April.

Rainfall information from the Bureau of Meteorology* shows that large sections of South Australia, New South Wales and the Northern Territory have recorded between nil* and 5mm of rainfall between April 1 and 28.

The situation doesn't look likely to improve in the near future.

May is likely to be drier than average for most of eastern Australia, according to the Bureau's latest predictions.

There's also a greater than 80 per cent chance of warmer than average days and nights from May to July in large parts of northern and eastern Australia.

And the Bureau's climate model suggests a short El Nino* weather system may develop in the coming months, which would increase the chances of drier conditions continuing in the east.

WHAT IS DROUGHT?
At it's simplest, drought is when there is less rain than usual.

This can lead to dry soil and dry rivers and dams. Less available water affects how well plants grow and how much animals have to eat, which means farmers have difficulty making money.

Drought can also increase the risk or severity* of bushfires.

Severe drought can mean that we run short of water to supply houses, towns or even cities.

When farmers have difficulty making money for a long time, the local and national economy can suffer. The economy is the movement of money from person to person and business to business around a community or country.

Farmers have to buy expensive feed for their animals, food prices can rise, fewer people are employed in farming and the businesses and towns that are directly involved in farming can suffer.

WHAT CAUSES DROUGHT?
There are several possible causes of drought, the most common being lack of rain.

If an area upstream along a river system gets little rain, that can cause a drought downstream.

If it is hotter than usual, water evaporates (or dries up) faster than usual and the soil, rivers and water storage areas can dry out.

Dry ground in turn increases temperatures, leading to even more evaporation.

People sometimes refer to this as the drought cycle: when it is hot, evaporation increases, which dries the ground out, which makes it hotter, which increases evaporation and so on in a cycle.

WHY IS AUSTRALIA VULNERABLE?
After Antarctica, Australia is the second-driest continent on Earth. More than 80 per cent of Australia gets less than 600mm of rain a year.

Air moves around the Earth in fairly regular patterns. Australia's position on the globe is one reason we are at risk of drought as we sit in what is called a high-pressure belt. High pressure in the atmosphere pushes air down from the sky towards land. For it to rain, we need the opposite to happen: low pressure, or air lifting up.

Another factor that puts Australia at risk of drought is a natural, cyclical* weather system called El Nino Southern Oscillation (ENSO). El Nino warms up the central Pacific Ocean to the east of Australia. El Nino pushes more air down towards land, which also prevents rain.

(The other part of ENSO is La Nina, which can deliver Australia lots of rain.)

Another weather system that can cause drought in Australia is the Indian Ocean Dipole, which moves air around the Indian Ocean to the west of Australia and determines how much rain falls over Australia.

A third weather system is the Southern Annular Mode (SAM), which operates to the south of Australia and determines whether cold fronts with rain in them make it to Australia.

HOW LONG DOES DROUGHT LAST?
No one can really know for sure how long a drought will last, but the people most likely to know are weather scientists called meteorologists.

They look at the way air and water is moving around the Earth and have complex models (based on science and observations from the past) to help them predict what will happen in the future.

WHAT IS A DROUGHT DECLARATION?
State and federal governments decide when an area is declared officially in drought.

For those affected, an official drought declaration is important as it triggers a range of types of help for people, businesses and communities.

Help can be in the form of money to buy food for people and farm animals; discounts or money back on some expenses such as fuel or interest, which is the cost of borrowing money from a bank; payments to charities that help support people in need and payments to drought-affected schools to help provide meals, books, uniforms or excursions.

HOW CAN I HELP?
Join our Adopt a Farmer campaign to help ease a family's pain from the drought.
Click HERE for details
GLOSSARY

National Farmers' Federation: a group that speaks on behalf of farmers

Bureau of Meteorology: Australian government's weather science agency

nil: zero

El Nino: weather system that warms up the central Pacific Ocean

severity: how severe or extreme something is

EXTRA READING Predicting drought and bushfires from space Big dry hitting farmers hard Mega dust storm 500m long blankets Sydney Dairy farming family farewells its cows QUICK QUIZ

1. Is it likely the drought will break in May?

2. Why does high pressure have to do with whether it rains?

3. What are weather scientists called?

4. How do we predict when a drought will end? Can we know for sure?

5. List some ways a drought declaration can help people, including anything you think of not in the story.

LISTEN TO THIS STORY
CLASSROOM ACTIVITIES
1. Wildlife and Drought
Many people are affected by drought as mentioned in the Kids News article. Animals and wildlife are one of the groups severely affected. Work with a partner and create a digital or poster presentation about wildlife in drought. Cover the following questions in your presentation;

What type of animals are affected by drought?

What happens to their habitats (where they live)?

How would the animal's food source be affected by the lack of water?

Other risks to animals during a drought?

Time: allow 45 minutes to complete this activity
Curriculum Links: English, Digital Technologies, Science, Personal & Social

2. Extension
Explain El Nino and La Nina in your own words. How do these affect Australia's rainfall and why?

Time: allow 15 minutes to complete this activity
Curriculum Links: English, Science

VCOP ACTIVITY
With a partner see if you can identify all the doing words/verbs in this text. Highlight them in yellow and then make a list of them all down your page. Now see if you and your partner can come up with a synonym for the chosen verb. Make sure it still makes sense in the context it was taken from.

Try to replace some of the original verbs with your synonyms and discuss if any are better and why.

HAVE YOUR SAY: Do you or someone you know live in a drought-affected area? Describe what that is like.
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.

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Adopt A Farmer: Kids News drought explainer

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Much of eastern and southeastern Australia is in what many are calling the worst drought in living memory for periods ranging from one year to seven years. National Farmers' Federation* president Fiona Simson said rain had been "pretty much non-existent" this April.

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(Image: © Ryan Hazen and Brandon Wilson)
Editor's Note: In this weekly series, LiveScience explores how technology drives scientific exploration and discovery.
Monitoring volcanoes is a tough gig. You've got to know what's going on - but getting too close is a deadly proposition.

Fortunately, technology has made it easier than ever to keep tabs on magma- and ash-spewing mountains around the globe. Much of this technology allows researchers to keep way back (even watching volcanoes from space) while keeping a close eye on volcanic activity. Some of these technologies can even penetrate cloud-swathed volcano peaks, allowing researchers to "see" ground changes that could signal an imminent eruption or dangerous lava dome collapse.
A gassy job
"You like to have multiple sources of information to maximize your ability to understand what is going on," said Geoff Wadge, the director of the Environmental Systems Science Center at the University of Reading in the United Kingdom. [ History's Most Destructive Volcanoes]

Monitoring volcanoes used to be a matter of getting boots on the ground. In-person fieldwork still happens today, of course, but now scientists have far more tools at their disposal to track changes around the clock.

(Image credit: U.S. Geological Survey)

For example, researchers at one time had to troop to volcanic gas vents, pull out a bottle to capture the gas, and then send the sealed bottle to a lab for analysis. That technique was time-consuming and dangerous, considering that a great number of volcanic gases are deadly. Now, scientists much more frequently turn to technology for these dirty jobs. Ultraviolet spectrometers, for example, measure the amount of ultraviolet light from sunlight absorbed by a volcanic plume. This measurement allows researchers to determine the amount of sulfur dioxide in the cloud.
Measuring movement
Another tool, in use at the Hawaiian Volcano Observatory since 2004, is the Fourier transform spectrometer, which works similarly but uses infrared light instead of ultraviolet. And one of the observatory's newest tricks combines ultraviolet spectrometry with digital photography, using cameras that can capture several gas measurements per minute in the field. All of this gas information helps researchers figure out how much magma is under the volcano and what that magma is doing.

Other high-tech techniques track volcano-triggered ground movement. The deforming of the ground around a volcano can signal an impending eruption, as can earthquakes. The Hawaiian Volcano Observatory has more than 60 global positioning system (GPS) sensors tracking movement at the state's active volcanic sites. These GPS sensors aren't much different from those in your car's navigation system or in your phone, but they are more sensitive.

Tiltometers, which are exactly what they sound like, measure how the ground tilts in a volcanic area, another telltale sign that something might be stirring below ground.

Having an eye in the sky is handy for tracking volcanic changes, too. Satellite imagery can reveal even minute elevation changes on the ground. One popular technique, called interferometric synthetic aperture radar (or InSAR), involves two or more satellite images taken from the same spot in orbit at different times. Changes in how quickly the satellite's radar signal bounces back into space reveal subtle deformations in the Earth's surface. Using this data, scientists can create maps showing ground changes down to the centimeter.

Satellites only pass over volcanoes every so often, however, limiting views to every 10 days at best, Wadge told LiveScience. To compensate, researchers are now deploying ground-based radar, similar to the radar used to track weather, to keep an eye on volcanic activity. Wadge and his colleagues have developed one tool, called the all-weather volcano topography imagine sensor (ATVIS), that uses waves with frequencies of mere millimeters to penetrate the clouds that often shroud volcanic peaks from view. With ATVIS, the scientists can "watch" the formation of lava domes, or gradually growing swellings, on volcanoes.

"Lava domes are very dangerous, because they pour out this highly viscous lava in a big pile, and eventually it collapses. In doing so, it produces pyroclastic flow," Wadge said.

Pyroclastic flow is a deadly, fast-moving river of hot rock and gas that can kill thousands in minutes. [ 50 Incredible Volcano Facts]

Wadge and his colleagues are testing ATVIS on the volcanically active West Indies island of Montserrat. Since 1995, the Soufriere Hills volcano on the island has been periodically erupting.
Cutting-edge tech
Radar measurements can also track flows of molten lava from space, Wadge said. Although satellite passes may occur only every few days, radar instruments can pinpoint locations down to a few feet (1 to 2 meters). Putting together images taken from space of a slow-moving lava flow can reveal a "movie-style" sequence of how the flow is advancing, Wadge said.

Increasingly, scientists are turning to unmanned drones to swoop close to a volcano while keeping humans out of harm's way. In March 2013, NASA flew 10 remote-controlled unmanned drone missions into the plume of Costa Rica's Turrialba volcano. The 5-pound (2.2 kilograms) drones carried video cameras filming in both visible and infrared light, sulfur dioxide sensors, particle sensors and air-sampling bottles. The goal is to use data from the plume to improve computer predictions of volcanic hazards such as "vog," or toxic volcanic smog.

On occasion, technology can even catch an eruption no one would have noticed otherwise. In May, Alaska's remote Cleveland volcano blew its top. The volcano is on the Aleutian Islands, so remote that there is no seismic network monitoring for explosions. But eruptions can disrupt air travel, so it's crucial that researchers know when an explosion is occurring. To monitor the busy Cleveland volcano, scientists at the Alaska Volcano Observatory use infrasound to detect low-frequency rumblings below the range of human hearing. On May 4, this technique enabled the scientists to detect three blasts from the restless volcano.

(Image credit: Jeff Schmaltz, LANCE MODIS Rapid Response Team at NASA GSFC)

In another case of remote volcano detection, in August 2012, a ship in New Zealand's Royal Navy reported a floating island of pumice measuring 300 miles (482 km) long in the South Pacific. The origin of the pumice would likely have remained a mystery, but volcanologist Erik Klemetti of Denison University and NASA visualizer Robert Simmon went sleuthing for the source. The two scientists searched months of satellite photos from NASA's Terra and Aqua satellites and found the first hint of an eruption: ash-gray water and a volcanic plume at an underwater volcano called the Havre Seamount on July 19, 2012.

"If you didn't know where to look, you would have missed it," Klemetti told LiveScience. Satellite imagery, along with other technological advances, has enabled volcanologists to detect more eruptions than ever before, he said.

"Go back 25 years ago, there are plenty of places where we wouldn't have had any clue that an eruption occurred," Klemetti said.

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Incredible Technology: How to Peer Into a Volcano (Safely)

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(Image: © Ryan Hazen and Brandon Wilson) Editor's Note: In this weekly series, LiveScience explores how technology drives scientific exploration and discovery. Monitoring volcanoes is a tough gig. You've got to know what's going on - but getting too close is a deadly proposition.

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Australia's farmers are battling to feed animals and plant crops after months - in some cases years - without enough rain.

It was the third driest May on record across the country, according to the Bureau of Meteorology*.

Farmers across Australia have bought two years' supply of hay in just six months, with hundreds of trucks driving the expensive feed thousands of kilometres to animals in need across Queensland, NSW and Victoria.

The NSW Premier today announced drought-relief funding as part of next week's state budget and the Country Women's Association of NSW met in Broken Hill to discuss how to support those in need.

NSW Premier Gladys Berejiklian travelled to Dubbo, NSW, to announce a $284 million drought package and $50,000 loans for farmers that will be interest-free for seven years.

She also announced $4 million in mental-health help for drought-affected areas.

The announcements come as community organisation Country Women's Association (CWA) gathered in Broken Hill today to discuss how its members can help.

"It's time for action and the kind of support that will make a real difference to the state's producers, and by convening* this forum* we hope some great initiatives* will be put on the table," said CWA NSW president Annette Turner.

"Drought doesn't just affect our farmers and landholders, it affects everyone who relies on our agricultural industries and the communities in which they live," she said.

Prime Minister Malcolm Turnbull travelled to western Queensland last week to meet farmers whose land has been in drought for seven years.

"You've got to get out of the city, you've got to get out of Canberra and Sydney and Brisbane. It's important to get out here, meet people and hear from them first-hand*. There is no substitute for that," Mr Turnbull said.

Farmers at Blackall, a town of 1416 people in Queensland's west, told Mr Turnbull that rural people needed help to cope with the drought.

More than 60 per cent of Queensland is officially in drought.

Blackall-Tambo Regional Council mayor Andrew Martin said Mr Turnbull showed empathy* to the community.

"We know he can't make it rain but if it does rain, we'll give him all the kudos* in the world," Mr Martin told AAP.

"We don't want sympathy ... what we really want is clear evidence of the Australian people investing in the long-term future of Australian agriculture," he told AAP.

"You put a dollar in and for every dollar a sheep farmer makes that creates $4-6 for the community ... I said you'll get your money back mate, big time."

Mr Turnbull said the government may soon announce improvements to the way people apply for drought assistance.

"The process of paperwork for applying for grants or concessional* loans is too arduous*," Mr Turnbull said.

Mr Martin, a sheep farmer, said his property was coping well, but others in the region were struggling and in extreme cases people had been forced to leave their farms.

Hay is in demand as feed for farm animals who haven't enough grass to eat.

Hundreds answered an advertisement last week for 7000 tonnes of hay from western Victoria. It's now on its way to buyers across Victoria, NSW and to as far north as Toowoomba in Queensland.

Although hay is expensive now, farmers were buying as much as they could because many farms haven't had enough rain for grass to grow in time for animals to eat over winter.

Australian Fodder* Industry Association chairman Frank McRae said two seasons of hay had been sold in the past six months as demand hit record levels. Mr McRae said there was now a procession* of hay trucks travelling large distances, with hay from South Australia and Victoria going to NSW and Queensland.

Mr McRae recently bought hay himself, and trucked it from 200km north of Adelaide to his farm at Orange, NSW. The transport cost was $5/km for the 1000km trip.

"In some cases, the freight* cost is going to be more than the cost of the fodder but people simply need it and so have to pay for it to come a long distance," he said.
EXTRA READING
Is the world running out of water? Ban rejected on live sheep exports WHERE IT IS WET AND WHERE IT IS DRY

Very dry in southern and the central coast of Western Australia, Gippsland and parts of northwest and north-central Victoria, areas of northeastern South Australia, parts of the east coast of Tasmania and large areas of NSW and Queensland.

It's wetter than usual in southwest Victoria and parts of western, central and southeastern Tasmania.

Floodwaters are on the way to Kati Thanda-Lake Eyre, about 700km north of Adelaide in South Australia. Rain in December, January and February in parts of the Northern Territory, South Australia and Queensland has slowly flowed through inland Australia towards Kati Thanda-Lake Eyre. Some water reaches Kati Thanda-Lake Eyre about every three years, but it only fills about four times every 100 years. The lake is the lowest point in Australia and is 15m below sea level. When it fills, it is the largest lake in Australia and covers 9500 square kilometres. It becomes an oasis of wildlife in Australia's dry centre.

Usually damp UK is preparing for drought this northern summer. Weather forecasters predict the hottest summer in 12 years and water levels in dams are low. Parts of the Lake District in northwest England, home to England's biggest national park, is already dry only two weeks into summer.

GLOSSARY

Bureau of Meteorology: government weather centre

convening: organising

forum: meeting for people to share ideas

initiatives: plans and ideas

first-hand: directly

empathy: understand and share someone's feelings

kudos: congratulations, credit

concessional: discounted or subsidised

arduous: difficult

fodder: feed such as hay

procession: line

freight: transport

LISTEN TO TODAY'S STORY QUICK QUIZ

1. Who said it was the third driest May on record?

2. Who went to Broken Hill and why?

3. How much of Queensland is in drought?

4. How far did Mr McRae truck the hay he bought?

5. What area does Kati Thanda-Lake Eyre cover when it is full?

CLASSROOM ACTIVITIES
1. Choose an action
In the story you have read about the different actions that are being taken to help farmers and communities affected by the drought. Choose one that you think is the most important and should be done first. Create a piece of persuasive writing that shows why this is the most important action and why it should be done first.

Time: Allow about 25 minutes
Curriculum Links: Critical and Creative Thinking, English

2. Extension
What are some other problems that the drought could be causing for local communities? Write a list of as many problems that you can think of. Then, think about solutions: things that can be done by the government, charities and people in your school or community to help. Next to each problem, write a paragraph explaining your solution and how it can help.

Time: Allow 30 minutes
Curriculum Links: Civics and Citizenship

VCOP ACTIVITY
After reading the article, with a partner, highlight as many wow words or ambitious pieces of vocabulary that you can find in yellow. Discuss the meanings of these words and see if you can use them orally in another sentence.

HAVE YOUR SAY: Why would drought affect people other than farmers? Who else could be impacted by drought?
Explain your answer using full sentences.

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Australian farmers battle drought after third driest May on record

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Australia's farmers are battling to feed animals and plant crops after months - in some cases years - without enough rain. It was the third driest May on record across the country, according to the Bureau of Meteorology*.

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A drought is a period of time when an area or region experiences below-normal precipitation. The lack of adequate precipitation, either rain or snow, can cause reduced soil moisture or groundwater, diminished stream flow, crop damage, and a general water shortage. Droughts are the second-most costly weather events after hurricanes.

Unlike with sudden weather events such as hurricanes, tornadoes, and thunderstorms, it is often difficult to pinpoint when a drought has started or when it has ended. The initial effects of a drought may be difficult to identify right away, so it may take weeks or months to determine that a drought has started. The end of a drought is hard to identify for the same reason. A drought may last for weeks, months, or even years. Sometimes, drought conditions can exist for a decade or more in a region. The longer a drought lasts, the greater the harmful effects it has on people.

Droughts affect people in a several ways. Access to clean drinking water is essential for all life, and sources of water may dwindle during a drought. Without the presence of water, people must bring in enough water from elsewhere to survive. Water is also needed for crops to grow. When not enough precipitation falls to naturally water crops, they must be watered by irrigation. Irrigation is possible only when there is enough water in nearby rivers, lakes, or streams, or from groundwater. During a drought, these water sources are diminished and may even dry up, preventing crops from being irrigated and causing them to die off.

One person studying these problems is Alexandra Cousteau, a National Geographic Emerging Explorer whose latest initiative is Blue Legacy. She started Blue Legacy to raise awareness that we live on a water planet and must take care of it. Cousteau, the granddaughter of the famed ocean explorer Jacques Cousteau, believes that water will be a crucial issue in this century. She predicts that water problems such as drought, storms, floods, and degraded water quality will create "water refugees:" people migrating in search of water. Cousteau stresses that we must do all we can to protect Earth's valuable freshwater resources.

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Below-average precipitation affects the amount of moisture in soil as well as the amount of water in streams, rivers, lakes, and groundwater.

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Without rain, the plants that are food for land animals and birds is in short supply or dies out all together. When waterways dry up the wildlife have no drinking water. Fish and other animals that live in streams, rivers and dams will die when the waterways dry up.

Drought and frogs

Frogs need water in which to lay their eggs and as a place for tadpoles to live as they develop into frogs. In a drought many creeks, rivers, wetlands, dry up and some species may not breed during the driest months.

Drought and reptiles

Reptiles can dig themselves into the ground under rocks, or hide under or inside logs, and go into a sleep-like state (it is called torpor) until the ground get moist again. Then they wake up and get active once more.

Bushfires in time of drought

In periods of drought there may be a greater risk of bushfires in forest and grasslands. The plant cover dries out and lightning strikes cause bushfires. Wildlife, farm animals and people are in danger from these fires.

Conserving water

People are told to stop washing their cars, to stop watering the grass and take other water conservation steps such as taking shorter showers and making sure that there are no dripping taps in their houses.

El Nino (it means 'the boy' in Spanish)

Scientists think that when a warm ocean current which they call El Nino occurs in the Pacific Ocean, it has an effect on weather around the world. Scientists think that when it flows, once every three to eight years, the air pressure over the sea is reduced and winds that normally bring rain to land blow less often and a drought occur.

Watch a video about El Nino: what causes drought?

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Without rain, the plants that are food for land animals and birds is in short supply or dies out all together. When waterways dry up the wildlife have no drinking water. Fish and other animals that live in streams, rivers and dams will die when the waterways dry up.

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Education resources for schools teachers and students - ABC Education

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ABC Education has 5000+ educational games, videos and teaching resources for schools and students. Free Primary and Secondary resources covering history, science, English, maths and more

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Home " Oceanography " What Causes a Tsunami?

What causes a tsunami?... A tsunami is a large ocean wave that is caused by sudden motion on the ocean floor. This sudden motion could be an earthquake, a powerful volcanic eruption, or an underwater landslide. The impact of a large meteorite could also cause a tsunami. Tsunamis travel across the open ocean at great speeds and build into large deadly waves in the shallow water of a shoreline.

Subduction Zones are Potential Tsunami Locations

Most tsunamis are caused by earthquakes generated in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces. The friction between the subducting plate and the overriding plate is enormous. This friction prevents a slow and steady rate of subduction and instead the two plates become "stuck."

Accumulated Seismic Energy

As the stuck plate continues to descend into the mantle, the motion causes a slow distortion of the overriding plate. The result is an accumulation of energy very similar to the energy stored in a compressed spring. Energy can accumulate in the overriding plate over a long period of time - decades or even centuries.

Earthquake Causes Tsunami

Energy accumulates in the overriding plate until it exceeds the frictional forces between the two stuck plates. When this happens, the overriding plate snaps back into an unrestrained position. This sudden motion is the cause of the tsunami - because it gives an enormous shove to the overlying water. At the same time, inland areas of the overriding plate are suddenly lowered.

Tsunami Races Away From the Epicenter

The moving wave begins travelling out from where the earthquake has occurred. Some of the water travels out and across the ocean basin, and at the same time, water rushes landward to flood the recently lowered shoreline.

Tsunamis Travel Rapidly Across Ocean Basin

Tsunamis travel swiftly across the open ocean. The map on this page shows how a tsunami produced by an earthquake along the coast of Chile in 1960 traveled across the Pacific Ocean, reaching Hawaii in about 15 hours and Japan in less than 24 hours.

Tsunami "Wave Train"

Many people have the mistaken belief that tsunamis are single waves. They are not. Instead tsunamis are "wave trains" consisting of multiple waves. The chart on this page is a tidal gauge record from Onagawa, Japan beginning at the time of the 1960 Chile earthquake. Time is plotted along the horizontal axis and water level is plotted on the vertical axis. Note the normal rise and fall of the ocean surface, caused by tides, during the early part of this record. Then recorded are a few waves a little larger than normal followed by several much larger waves. In many tsunami events, the shoreline is pounded by repeated large waves.

Find Other Topics on Geology.com:

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Tsunami Geology - What Causes a Tsunami?

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Home " Oceanography " What Causes a Tsunami? What causes a tsunami?... A tsunami is a large ocean wave that is caused by sudden motion on the ocean floor. This sudden motion could be an earthquake, a powerful volcanic eruption, or an underwater landslide. The impact of a large meteorite could also cause a tsunami.

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(i) Undersed earthquakes:

Although tsunami may be caused by landslides, volcanic eruptions or even by the impact of a large meteorite falling on the ocean, most destructive tsunamis are generated by massive undersea earthquakes, occurring at depth less than 50 km with the epicentre or fault line near or on the ocean floor.

A strong undersea earthquake with magnitude greater than 7.5 on the Richter Scale tilts and deforms large areas of the sea floor ranging from a few kilometres to 1000 kilometres and even more. As the sea floor is tilted or deformed by the tectonic earthquake (earthquake associated with the earth's crustal deformation), the sea water above is displaced from its equilibrium position.

Waves are formed as the displaced water attempts to regain its equilibrium under the influence of gravity. It is this vertical movement of the entire water column that generates destructive tsunami waves (Fig. 8.5).

The displacement of sea floor and occurrence of an earthquake and formation of tsunamis can best be explained on the basis of plate tectonics. When two converging lithospheric plates come closer together heavier plate is thrust under the lighter plate and displacement of the crust takes place at the subduction zone. A fault is created and an earthquake occurs, giving rise to tsunamis.

According to Law of Conservation of Energy, energy cannot be created or destroyed but can be transferred from one form to another. Thus the potential energy that results from pushing water above the mean sea level is transferred to kinetic energy that initiates the horizontal propagation of the tsunami waves.

It must be noted that a tsunami is usually not generated if the sea floor movement is horizontal.

Besides, not all undersea earthquakes create tsunami, as it depends upon the nature and degree of displacement of seawater column. It is only the vertical displacement of the seawater due to abrupt, jerky movements of fault blocks on seabed that gives birth to tsunamis. Once formed, the monstrous waves soon begin their journey towards the nearest coastline, ringing the bells of doom (Fig. 8.6).

(ii) Landslides:

Tsunami waves are also generated by displacement of seawater resulting from landslides as well as rock falls, icefalls etc. Construction work of an airport runway along the coast of Southern France in the 1980s caused an underwater landslide.

This triggered the destructive tsunami waves in the harbour of Thebes. Underwater landslides may also occur when a strong earthquake shakes the sea floor, thus forming tsunamis. These waves rapidly travel away from the source due to dissipation of energy, and create havoc in the nearby coastlines.

(iii) Volcanic Eruptions:

Whenever a violent volcanic eruption takes place under the sea, it causes sudden displacement of a large volume of seawater and tsunami waves are formed. Similarly, when the roof of a volcano collapses that has a large empty magma chamber owing to continuous flow of lava, a crater sometimes as large as one kilometre in diameter is formed. As the seawater gushes into this crater, the water column of the sea is disturbed which gives rise to tsunami waves.

One of the largest and the most destructive tsunami ever recorded was generated on August 26, 1883 after the explosion and collapse of the volcano of Krakatoa in Indonesia. This explosion generated waves with a towering height of about 40 m, that wrecked havoc on the coastal areas along the Sunda Strait in both the islands of Java and Sumatra killing more than 36,000 people. It is believed that the destruction of the Minoan civilisation in Greece in 1490 B.C. was caused by tsunamis which were formed by the explosion of the volcano of Santorin in the Aegean Sea.

(iv) Meteorites and Asteroids:

There is a potential danger of tsunami being formed by the fall of meteorites and asteroids in the ocean. Researchers in California have developed a computer simulation depicting the ocean impact of asteroid 1950 DA, a gigantic space rock that would be very close to the earth in 2880.

Although the possibility of such an impact is very remote, the computer model definitely gives the researcher an insight into the destructive power of tsunami caused by near-Earth object. Some of the meteorites have been uncomfortably close to the earth and could wreck havoc in different forms including tsunamis.

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4 Major Reasons for Formation of Tsunami - Explained!

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ADVERTISEMENTS: Some of the major reasons for formation of tsunamis are as follows: (i) Undersed earthquakes: Although tsunami may be caused by landslides, volcanic eruptions or even by the impact of a large meteorite falling on the ocean, most destructive tsunamis are generated by massive undersea earthquakes, occurring at depth less than 50 km with [...]

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A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.

What Causes a Tsunami?

These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become a tsunami.

Most tsunamis-about 80 percent-happen within the Pacific Ocean's "Ring of Fire," a geologically active area where tectonic shifts make volcanoes and earthquakes common.

Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth's ancient past, by the impact of a large meteorite plunging into an ocean.

Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour-about as fast as a jet airplane. At that pace, they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.

In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.

What Happens When It Hits Land

A tsunami's trough, the low point beneath the wave's crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave's crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.

A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.

Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.

The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.

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Learn more about these destructive surges of water from National Geographic.

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Tsunami is a Japanese word which means 'harbour wave'

Earthquakes under the sea are the main causes of Tsunamis

The biggest tsunami ever was at Lituya Bay, Alaska on July 9, 1958

Earliest tsunamis was in Sicily 8,000 years ago

Landslides and volcanoes can also cause tsunamis

Introduction
A tsunami is a powerful series of waves caused by a disturbance under water. This is usually an earthquake under the sea.

The waves travel through the ocean and cause devastation when they reach land. Humans are often killed and buildings destroyed when the water hits the coast.

To fully understand how tsunamis are caused we must have an understanding of tectonic plates, earth quakes, and finally, water.

Tsunami is a Japanese word meaning 'harbour wave' that refers to a series of large ocean waves that hit a shoreline. The word originates from Japan because this is the country where tsunamis are most common.

These tsunami waves may be as long as 100km and travel across the ocean at speeds of up to 800kmh. There may be a constant stream of waves that that batter the shore for between 10 and 60 minutes.

Tsunamis are also known as tidal waves, due to their large and powerful nature. They have been depicted throughout history, art, television and film as something terrifying, cataclysmic and almost Armageddon-like.

Tsunamis are caused by sudden movements of the earth that happens under the sea. Often the most destructive Tsunamis are caused by earthquakes but causes can also include volcanic eruptions, landslides or even a comet hitting the sea.

Landslides cause tsunamis when the debris falls into the water. This has the same effect of dropping a large stone into a pool - big ripples are created. But when this happens in the sea and it is thousands of tonnes of rock and earth falling into the sea a very large ripple, more like a tidal wave is created. This travels across the sea until it comes into contact with land and a tsunami is formed.

Volcanoes cause tsunamis when there is an eruption. The volcano can either be on land or under the sea, in which case it is known as a submarine volcano. If the volcanic eruption happens on land, the tsunami is caused by debris and lava from the volcano flowing into the sea, which once again causes a bug ripple.

If the eruption happens under water, the enormous power of the eruption sends shudders through the earth and disrupts the water. The water in the sea then breaks into waves which travel across the ocean until they come into contact with a coast. Here, a tsunami is formed.

The most common cause of a tsunami is fro earthquakes. This is what caused the Boxing Day tsunami in the Indian Ocean in 2004 and it is also the reason behind the 2011 Japan tsunami.

To understand how earthquakes cause tsunamis we must first fully understand what causes earthquakes. Remember, tsunamis are an after-effect of an earthquake.

The earth sits on about a dozen tectonic plates. These are large floating pieces of hard rock that are constantly moving and fit together around the world like a jigsaw.

Undersea earthquakes happen when one of these plates is rubbing against another at a plate boundary. The two plates may become stuck as the heavier plate tries to slide under the lighter other. This causes a build up of pressure in a process knows as subduction.

As the heavier plate continues to slide beneath the lighter plate, it causes the lighter plate to bend downwards with the pressure. A point comes when the lighter plate can no longer take the intense pressure and suddenly snaps back up to the surface where it had been before.

The incredible force of the earth's plate shooting upwards in the water causes a huge rise in sea level. A vast body of water moves upward - like a huge mountain of water in the sea.

Everybody knows that what goes up must come down. This is particularly true for water which always likes to form a nice flat surface. So once the mountain of water has risen up the next step is for the sea to level itself out.

The mountain of water comes back down. This pushes the water that was underneath it outwards. The force of the water moves through the ocean causing an underwater force that travels for hundreds of Kilometres. The force of the water can reach speeds of up to 800kmh as it surges through the ocean. The energy is underwater and is not noticeable on the surface.

As this force travels through the ocean it may eventually reach the shore. At this point, the sea becomes shallower. However, the energy in the water is still the same. The enegery is compressed and the water is pushed upwards. This is how the energy is transferred from being underater into waves on the surface.

Unfortunately nothing can be done to prevent Tsunamis. However, there are several organisations that use complex technology to monitor movement of the earths plates and sudden changes in water movement. There are also warning and evacuation procedures in place around countries like Japan and Hawaii where Tsunamis are frequent.

Any sudden earthquake that happens underwater will be detected in the same manner of on on-shore earthquake. These are measured in the Richter scale. If this is recorded then warning systems can sometimes be activated to evacuate people.

Japan - March 11, 2011

Indian Ocean - 26 December 2004.

Papua New Guinea - 17 July 1998

Sea of Japan - 26 May 1983

Alaska Britis Columbia - 27 March 1964

Chili - 22 May 1960

Aleutian Islands - 1 April 1946

Read more about the biggest tsunamis in history.

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Tsunami is a Japanese word which means 'harbour wave' Earthquakes under the sea are the main causes of Tsunamis The biggest tsunami ever was at Lituya Bay, Alaska on July 9, 1958 Earliest tsunamis was in Sicily 8,000 years ago Landslides and volcanoes can also cause tsunamis Introduction A tsunami is a powerful series of waves caused by a disturbance under water.

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Tsunami Information Centre Website

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Indian Ocean Tsunami Information Center | Tsunami Info | About Tsunami | What Causes Tsunami

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Encyclopaedia Britannica

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© Christophe Fouquin/Fotolia

As natural disasters go, tsunamis are among the worst in terms of overall destruction and loss of life. They rival earthquakes in their ability to suddenly devastate a wide area. In recent years massive tsunamis have caused extensive damage in northern Sumatra and Thailand, parts of Japan's Honshu Island, and parts of Chile. So what are tsunamis, and what causes them?

A tsunami is a catastrophic ocean wave that is usually caused by a submarine earthquake, an underwater or coastal landslide, or the eruption of a volcano. Tsunamis can also result from the impact of a meteor or comet in a body of water. The word tsunami in Japanese means "harbor wave."

Much like when a rock plunges into a still pond, once a tsunami-generating disturbance in the water occurs, a train of outward-propagating waves comes from the disturbance's central point. These waves can travel as fast as 800 km (500 miles) per hour, with wavelengths that extend from 100 to 200 km (60 to 120 miles). However, in the open ocean, amplitudes (heights) of the waves are very small, only about 30 to 60 cm (1 to 2 feet) high, and the period of the waves (that is, the length from one wave crest or trough to the next) can last from five minutes to more than an hour. As a result, people on ships far from shore barely perceive the passage of the tsunami underneath them.

As the tsunami approaches the coast of an island or a continent, friction with the rising sea bottom slows the waves, and wavelengths become shortened while wave amplitudes increase. In essence, fast-moving water from further out to sea stacks itself on the slower-moving water near the shore. Just before the tsunami reaches the shore, the water is drawn back by the sudden change in wave activity, effectively pulling the tide out far from where it normally meets the beach. When the tsunami reaches the shore, it can push far inland (limited only by the height of the wave). Waters may rise as high as 30 meters (about 100 feet) above normal sea level within 10 to 15 minutes and inundate low-lying areas.

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Tsunamis are ranked among the world's most destructive forces. But what are they, and how are they generated?

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Prevention Web Website

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What causes tsunami? | PreventionWeb.net

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When an undersea landslide occurs (perhaps after a nearby earthquake) a large mass of sand, mud and gravel can move down the slope. This movement will draw the water down and may cause a tsunami that will travel across the ocean.

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Reuter's Website

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TOKYO (Reuters) - Half a century of expertise in dealing with disasters in Japan, where earthquakes are a way of life, probably saved thousands of lives after Friday's massive tremor, but even that finely honed response system could not prevent widespread devastation.

The 8.9 magnitude quake, and the 10-meter high tsunami it triggered, are believed to have killed at least 1,000 people along the coast of northeastern Japan. Most of the casualties were probably drowned by the torrent of water that swept away everything in its path.

The word tsunami itself is Japanese - meaning "harbor wave" - reflecting the quake-prone country's long and sometimes tragic experience with the phenomenon.

Japan's earthquake monitoring and tsunami warning system is one of the most sophisticated - and costliest - in the world, befitting an economically developed, seismically cursed nation that, on average, experiences a quake every five minutes.

Buildings are, by law, erected to withstand tremors.

The monitoring system has been upgraded several times since its inception in 1952, and especially after a 7.8 magnitude quake in 1993 triggered a 30-meter high tsunami that devastated the coast of Hokkaido. The meteorological agency had issued a warning after the quake, but it came too late for the hundreds of people who were killed.

The tsunami warning service, which has at least six regional centers, currently sends signals from 180 seismic stations across Japan and about 80 water-borne sensors are monitored 24 hours a day by a computerized Earthquake and Tsunami Observation System (ETOS).

To get warnings out quickly, the Japan Meteorological Agency and media have developed a system to superimpose alerts on TV screens as soon as they are issued.

In addition, warnings are sent to local officials via a satellite system that acts as a back-up to land-based communications. Local officials activate sirens and loudspeaker systems, and also decide if an evacuation advisory is needed.

Japan also has built countless concrete breakwaters and floodgates to protect ports and coastal areas around the country, although experts had said they might not be enough to prevent tsunami-caused disasters, and could even worsen the damage by keeping the water from receding.

The warning system comes with a hefty price tag - about $20 million annually to keep it running.

Forecasting tsunami is only part of the battle, however.

Equally important is making people in areas where tsunamis are uncommon aware of the need to evacuate.

Even in Japan, some people wander down to the shore after a tsunami warning to have a look and many ignore warnings because often no big tsunami strikes. Some people in areas were tsunamis are uncommon also do not see the need to evacuate.

Japan has also tightened building codes and bolstered the government's ability to respond quickly to earthquakes since a 7.3 tremor killed more than 6,400 in the western city of Kobe in 1995.

Located in the "Ring of Fire" arc of volcanoes and oceanic trenches partly encircling the Pacific Basin, Japan accounts for about 20 percent of the world's earthquakes of magnitude 6.0 or greater.

In 1896, a magnitude 8.5 Sanriku earthquake and tsunami left more than 22,000 dead in northeastern Japan. Another 8.1 quake, and resulting tsunami, hit the same region in 1933, killing 3,064.

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Japan's top-notch tsunami preparation may have prevented worst

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TOKYO (Reuters) - Half a century of expertise in dealing with disasters in Japan, where earthquakes are a way of life, probably saved thousands of lives after Friday's massive tremor, but even that finely honed response system could not prevent widespread devastation.

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Website

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Introduction

The magnitude 9.0 Japan's Tohoku Earthquake occurred at 14:46 local time on Friday, 11 March 2011, 125 km east coast of Honshu and 380 km far from Tokyo and rattled the large parts of Japan and some part of east China and Russia with 30 km depth of the hypocenter ( 1). This earthquake that lasted approximately 3 minutes (170 seconds) caused a 130 km long by 159 km wide rupture zone on the pacific plate subduction zone and followed by a huge tsunami with more than 40 meter waves. The destructive aftermaths of this incident made an irreparable disaster not only for the Japan, but also for the whole world because except for the enormous death toll and debris, the damages of nuclear power plants were a hazardous unexpected tragedy.

Casualties and damages

According to the report of the Japanese National Police Agency, 15854 dead, 3167 missing and 26992 injured across twenty prefectures are the result of this devastating earthquake and tsunami which ruined more than 125000 buildings. Moreover, it caused long blackouts for more than 4.4 million buildings and left 1.5 million buildings out of water for days ( 2), also large fires were triggered one after another even for weeks after the main quake. Explosion and demolition of the Fukushima I Nuclear Power Plant (Fukushima Daiichi), which generated radioactive contamination near the plant's area with irreversible damages to the environment, was one the most significant issues of this catastrophe and ranked 7 (the most sever level for nuclear power plant) based on the International Nuclear Event Scale, similar to the Chernobyl disaster on 26 April 1986 ( 3). Therefore, it is not strange to consider to this earthquake as the most important destructive seismic event of the beginning of the twenty first century in the advanced industrial world.

Losses intensified by hit of the tsunami as the statistics shows it was more fatal () and also more buildings destroyed by its strike; However, the quake was the main cause of the partial damage of buildings ( 4). manifests the building losses distribution through affected areas and reveals the relative impact of the earthquake vs. tsunami in each prefecture of Japan ( 4).

Seismology and Seismic History

This mega thrust earthquake is categorized as a great earthquake with the magnitude more than 8 in scientific seismological classification ( 5). Over 1000 aftershocks, some of which were larger than the recent catastrophic earthquakes in Iran such as Bam, Iran 2003, hit the area since the main shock. Regardless of the consequent tsunami, the Tohoku Sendai Earthquake (2011) is the largest recorded earthquake in the history of Japan in terms of magnitude while the territory of Japan is known by numerous and critical earthquakes. There are two momentous calamitous earthquakes in history of Japan: The great Kanto earthquake with magnitude of 7.9 on 1 September 1923 which destroyed Tokyo and Yokohama rigorously by the severe quake and subsequent fires and caused more than 143000 deaths ( 6, 7); and the Kobe earthquake (also known as Hanshin- Awaji earthquake) with magnitude of 6.9 on 17 January 1995 that left more than 6400 demises ( 6, 8). The Kanto incident is still the deadliest earthquake in Japanese history and the Kobe earthquake was the most costly natural disaster of the world since Tohoku Earthquake 2011 ( 9).

Methodology

Japan crisis management system

Japan has an overall population of 127 million and is one of the most densely populated countries in the world (340 persons per Km), where the population highly concentrated around Tokyo ( 6). This earthquake-prone country as a pioneer in crisis management has a comprehensive plan for preparing against disasters, consists of the Central Council for Accident Prevention, chaired by Prime Minister, set of cohesive rules for immediate response to all of the unexpected incidents, the advanced research system and the extensive public education about disasters. As the result of this plan, in the case of an accident, people, government officials and rescue departments know exactly what to do while the alarm is sounded, without chaos.

It was after the disastrous Kobe earthquake of 17 January 1995 (M6.9) that crisis management of Japan greatly promoted since the government set up a GIS system and a general computer network. This system contains different subsystems to operate all disaster related functions from prevention before the disaster to damage evaluation after it ( 10). Additionally, the most advanced earthquake and tsunami early warning system of the whole world is installed in Japan during 2003 to 2007, which is one of the main parts of this crisis management system. This warning system had a considerable role in Tohoku 2011 earthquake to reduce losses and save lives. Several Japanese media such NHK channel and also mobile phone networks have the most responsibility of broadcasting the news of early warning system.

In management of the 11 March 2011 crisis, one of the most facilitative factors for emergency managers was proper behavior of people who follow the commands cautiously. In other words, the " social capital" in this country had a significant role in recovery after the incident as people's high respect to roles and moral values and their solidarity prevent them from influx for aid and looting and motivate them to consider the public benefits instead of self-interests.

Response to the disaster

Immediately after the event, The Government of Japan (GOJ) held National Committee for Emergency Management, headed by Prime Minister. The government declared an emergency in effected area and dispatched the Japan Self Defense Forces for rescue operations ( 11). All ministries and departments such as Foreign Ministry, Ministry of Transport and Ministry of Health were involved in this response, also local offices of disaster response in all prefectures begins their operations as their duty was already clear. The Ministry of Health was in charge of preparing suitable vehicles for supplying water and assigning hospitals for remedy of casualties and people who have been exposed to radiation. Ministry of Agriculture, Forestry and Fisheries with Ministry of Finance were responsible for providing food, portable toilet, blanket, radio, gasoil, torch, dry ice and other essential things. By the command of the government, all of the main highways in north of the country were completely occupied for emergency response activities. Besides, the transport systems includes subway, shipping and the Shinkansen bullet train ceased their activity in Sendai and Tokyo instantly after the quake.

Moreover, at the day of event the Government of Japan declared "the state of nuclear emergency" due to the threat posed by reactors in two Fukushima nuclear power plants (I and II) and 140,000 residents within 20 km of the plant evacuated. At 15:36 JST (Japan Standard Time) on 12 March, there was an explosion in the reactor building at Unit 1 in Fukushima Daiichi (I) power plant. At 11:15 JST on 14 March, the explosion of the building surrounding Reactor 3 occurred. An explosion at 06:14 JST on 15 March in Unit 2, damaged the pressure-suppression system. When the disaster began on 11 March 2011, reactor unit 4 was shut down for periodic inspection and all fuel rods had been transferred to the spent fuel pool on an upper floor of the reactor building. On 15 March, an explosion damaged the fourth floor rooftop area of the unit 4 reactor.

Japanese Red Crescent Society (JRC), which had a substantial role in initial relief operations and temporary housing, deployed its teams promptly. JRC performed properly for accommodation of refugees and evacuees in schools, public buildings, and shelters. This society adapted its operations to all other rescue organizations and NGOs, which deployed to the area later.

Construction of temporary housing in quakestricken prefectures was begun 8 days after the event and the first set of buildings was expected to be ready within a month ( 12). In addition to medical aids, therapists and social workers were dispatched to the affected zone by Health ministry and then in coming days the concentration of treatments was shifting to psychotherapy from physical sicknesses. In addition, this Ministry performed required actions in order to control and inhibit infectious diseases and encouraged people to use masks ( 2).

Fire was reported in eight prefectures after the quake. Fire suppression of gas pipeline took a few days and fires in Cosmo Oil Installations and some other refineries lasted 3 days. Generally, the number of fires increased from 44 to 325 in a week, but its growth rate declined. All the fires, which were triggered after the earthquake, were under control of Japanese Police and it can be said that they could prosperously cease and extinguish them ( 13). On the other hand, these fires and breakdown of six out of nine oil factories faced the affected areas with fuel shortage. The gas pipeline repairing operation had a slow progress, too. Therefore, about one million liter gasoline per day had been carried to the damaged areas by tankers and then by cargo train in order to compensate lack of fuel. Low displacement capacity of oil and coal shipments caused delays in delivering fuel loads, which were importing from countries such as South Korea and Russia, to consumers ( 13).

Due to the shutting down of the power plants which were cracked by the quake and tsunami, authorities begun imposing sporadic power cuts nationwide to make up for production losses. Correspondingly, large factories like Toyota and Sony halted their production activities and many citizens in Kanto reduced their power consumption in order to abridge the time of blackouts ( 14).

Nuclear crisis

There are 54 reactors in Japan, but since the tsunami on March 2011 that destroyed Fukushima plant () and triggered the world's worst nuclear crisis in 25 years, the government did not allow to restart any reactor that have undergone maintenance due to public safety ( 15). The first nuclear power plant of Japan was initiated with collaboration of English corporations in 1973, but these kinds of power plants then developed by American technology. All the 11 reactors in Fukushima 1, Fukushima 2, Onagawa and Tokai nuclear power plants automatically safe shut down after the quake; however, arrival of tsunami debris with high waves damaged reactor's cooling systems and eventually, resulted hazardous explosions. This could have been prevented if the designers had estimated the probable maximum altitude of the tides more prudently. The explosion occurred in 4 of the 6 reactors of Fukushima 1 power plant one after another, while the unit 3 reactor was more damaged and more intensively contaminated the surrounding area. A few hours before each of these explosions, authorities warned about the cooling system breakdown, ordered to evacuate neighboring people and tried to drop the pressure of vapors, but in all of them the hydrogen explosion finally happened.

The owner of the Fukushima Plant, The Tokyo Electric Power Company (TEPCO), is accused of mismanagement and hiding the truth about the real damage caused by the disaster at the expense of saving the company ( 16). Moreover, according to reports, it was expected that TEPCO safely shutdown reactors of Fukushima 1 nuclear power plant approximately a month before the 11 March earthquake, but apparently the company avoided this action because of economic issues.

Over 140 thousand residents were evacuated from 20 Km around the Fukushima plant. Radiation penetrated in foods and drinking water in 30 kilometer far from the evacuated area, and authorities inhibited distribution of these polluted foodstuffs ( 13). U.S. Department of Energy announced a wide area beyond 80-kilometer radius around the Fukushima plant is affected by radiation ( 17).

The explosion of Fukushima power plant and its aftermaths aroused public concerns about nuclear energy in Japan and other earthquake prone countries. Consequently, other power plants, which were not resistant to the probable future quakes with magnitude more than 8, ceased they activity gradually sequentially by the command of The Prime Minister. TEPCO shut its last operating nuclear reactor in 26 March 2012 for regular maintenance, leaving just one running reactor supplying Japan's creaking power sector ( 15). Then again, on 10 April 2012 (less than a month later), as the summer arrives, while Japan is going to struggle with electricity shortage, the government planned to restart one of the atomic plants in Kansai after approval its safety ( 18) and faced with people's disagreement.

Furthermore, the nuclear crisis has led to growing opposition against atomic power plants in other countries, particularly in Germany, where thousands of citizens participated in an anti-nuclear demonstration. This disapproval also affected the regional election results unbelievably. In the state of Baden-Wurttemburg, which traditionally had gone with Christian Democratic Union party for 58 years, most of people voted for the Green Party who was against with 17 nuclear reactors in this country ( 19).

Results: Crisis consequences

The 11 March 2011 earthquake had many deleterious environmental impacts that take a long time to recover. Apart from radioactive materials dispersed due to nuclear plant explosions and discharging polluted radioactive water of cooling systems to the sea, the subsequent tsunami induced huge amount of debris contains building materials, broken boats, cars, trees and etc. that cause environmental harmful issues.

Radioactive pollutions and radiations as the most harmful repercussions of the earthquake induced fear and concern among resident. Most evacuees did not return to their home even after the safety of the regions was assured. However, the government tried hard to convince people to return to their homes by checking and promulgation the radiation doses constantly, but just the population of old people gradually increased. Therefore, satisfying young people to come back will be a demanding challenge for the government.

A year after the event, anecdotal evidence suggests that fear of radiation, rather than contamination itself, is triggering stress-related problems among nuclear evacuees ( 20), despite the experts emphasized that the doses are too low to develop cancer. Even in more distant areas, where completely secure, parents do not allow their children to play outside. Although there have been no recorded deaths from radiation in Fukushima, according to the Yomiuri Shimbun newspaper, psychological trauma associated with evacuation, pneumonia and heart disease were much more fatal based on statistics. Therefore, in months after the event, Japanese Red Cross concentrated on mental health issues.

Also, the tsunami had adverse effects on agriculture and requires long-term reconstruction at least for 2 or 3 years. In addition, the fishing industry faced to critical continuing problems. Most reports acknowledged that Japan's food exports could be limited by Japan's current Production and supply shortages, along with boosting food safety concerns and possible long-term radiation threats to its food production, in contrast possibly its need for food imports will increase in future ( 21).

Moreover, since Japan is a country covered by jungles, wooden houses are very prevalent in this country and despite the dropping rate of wood imports in recent decade, due to boom reduction of this kind of homes; the Tohoku earthquake caused a 70% rise in wood import rate by enhancement of the wood demand. This made a competition for wood exporters from different countries such as Australia, America, and China.

One of the important impacts of the Fukushima power plant explosion is its psychological consequences. Regardless of common diseases such as infectious ones that break out after earthquakes, the radioactive contamination permeated to the residential areas where people was living, working and planting brought a ten times fatal disease, which is hopelessness and untruthfulness. People know they should leave anything they had include home and agriculture plant and this lead them to an ambiguous future which is unstable and they should build everything from beginning. The increase in number of suicides in power plant's surrounding areas even far from them and farmers concern about safety of their productions and land even 100 kilometers far from the affected zone prove the strength and influence of this issues.

Japan should also challenge with the problem of enhancing of unemployment. Large number of refugee and evacuees left their home and moved to other cities. Also, workers of car and electronic factories are now jobless by factory closure so they are forced to immigrate ( 22). Japanese government created around 20 thousands of jobs in the emergency measures to combat the effects of the disaster in a month, but the number of the unemployed ones was much more than created jobs ( 23). Additionally, women especially in rural areas, who used to were involved in tough works such as agriculture and fishing, after the disaster have to work in other posts and try different occupations in order to help to family economic. Many of these women take apart in protests against Fukushima power plant issues in Tokyo in October and November 2011. It seems that this earthquake has modified the women life style in affected prefectures as now they have more important roles in family issues and it is big change in an almost traditional male-dominated Japan.

Following the shutting, the Fukushima power plant, on February 2012, the House Foreign Relations Committee off Japan approved to export its nuclear equipment to Vietnam and Jordan. Also Japanese companies signed agreements with India, Bangladesh, and Turkey about construction, operation, and management of nuclear power plants in these countries, despite environment activist's oppositions in recent months against these transactions and their high costs and permanent detriments for humans and earth. Actually, the nuclear power in spite its approximate low costs, have many hazardous disadvantages that the Japan 2011 accident and the Chernobyl 1986 are good samples for this fact. Unfortunately, developing countries do not consider these consequences and endanger the environment and people's lives while Japanese authorities are just accenting their own country's benefits.

Conclusion

In Tohoku earthquake and tsunami of 11 March 2011 despite the unprecedented scale of the quake itself, infrastructures and buildings mostly remained standing and proved the resilience of Japan is planning laws especially in constructions and earthquake technology. Hence, if the earthquake had been the sole problem, then Japan could have claimed for itself a momentous prosperous in planning for the impact of a major earthquake. The reason of Japanese plans failure was the large-scale tsunami, which had higher waves than what was assumed in designing. In addition, the fact that Japanese authorities considered economic benefits more than safety and moral factors exacerbate the situation. Even after the disaster, this country just cared about economic benefits and sought to export its technology to other countries.

However, this disaster was a motivation for people and governments worldwide to replace clean energy with the hazardous one and it was a reminder to decommissioning the old and unsafe operating power plants. Thus, the Metsamor nuclear power plant in Armenia, Iran's neighboring country, is a critical threat in the region with high seismic risk. Governments had to plan long-term and costly solutions to replace the nuclear energy with clean and renewable forms of it with respect to criteria and moral values, not only the benefits.

Although energy issues and management of power plant's crisis was a blind spot in Tohoku disaster management, Japanese social ethics and their manner in dealing with the problem were the most advantageous points. Discipline, maintaining calm, public confidence in managers and scientific management based on the plans helped to improve the situation more quickly (). Long queues of Japanese People for food and facilities instead of chaos, which we mainly consider in developing countries, could be a good proof for other countries that enterprising on educating people about how to act in crisis is very operative and effective in enhancement of disaster management.

The 11 march 2011 earthquake was an alarm for seismologist all over the world, particularly in Tehran as a capital city, to revise their methods and evaluation of estimating the plausible time and magnitude of earthquake. It could be an alarm for us to be more meticulous and cautious about the earthquake hazard as prepared and industrialized Japan with the most modernized technology confronted many extensive troubles, which were out of their predictions. Now we should ask this question "how much we are prepared in an earthquake prone country with a capital located exactly on active faults?"

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Crisis Management of Tohoku; Japan Earthquake and Tsunami, 11 March 2011

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The magnitude 9.0 Japan's Tohoku Earthquake occurred at 14:46 local time on Friday, 11 March 2011, 125 km east coast of Honshu and 380 km far from Tokyo and rattled the large parts of Japan and some part of east China and Russia with 30 km depth of the hypocenter ( 1).

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Website

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No matter how many times you watch it, the footage of the 2011 Japan earthquake and ensuing tsunami remains a chilling reminder of the immense forces unleashed by natural disasters. This particular catastrophe led to the worst nuclear meltdown since Chernobyl, left over 28,000 people dead or missing, and caused damages as high as US$235 billion.

Japan, and in particular the big cities along its coast, remain at danger of future tsunamis. And while the government tries various approaches to limit the potential damage, like building sea walls, the fight against tsunamis continues.

One city that is particularly at danger is the city of Kawasaki. It sits next to a major fault line underneath the Nankai Trough, where historically earthquakes have produced damaging tsunamis. It's also located just south of Tokyo, close to one of the most densely populated parts of the country. The impact of a tsunami here would be huge, making it an ideal place to test new approaches for disaster response.

Japanese tech company Fujitsu is trialling artificial intelligence in Kawasaki to predict tsunamis and help local governments shape disaster response plans. The initiative is a public-private collaboration with the local government and academic institutions.
Keeping up with the rising tide
Given how quickly tsunamis move, time is of the essence for evacuation efforts. The project focuses on real-time analysis, which is only made possible by advances in technology. "The idea of the initiative is to investigate how cutting-edge technologies, including AI and supercomputers can be used to reduce harm and the impact of a tsunami," Andrew Kane, the company's spokesperson told GovInsider.

"The goal ultimately will be to support communities to become more sustainable and prepared to respond when a tsunami strikes," he adds.

Fujitsu has been working with the International Research Institute of Disaster Science (IRIDeS) in Kawasaki since November 2017, and the project will last until the end of this year.

"The goal ultimately will be to support communities to become more sustainable and prepared to respond when a tsunami strikes."
A dense offshore sensor network
To improve the quality of the predictions, the project combines two simulations: incoming tsunamis and evacuation behaviour. The tsunami flooding simulation is based on high-resolution modelling technology that relies on supercomputers to accurately reproduce the flood dynamics. Using observational data, for example, from off-shore sensors the simulation estimates factors like the wave height and the arrival time.

The evacuation simulation on the other hand combines a city-specific model with a simulation of human behaviour and movement, allowing researchers to evaluate the human risks caused by a tsunami. "This could be used to create better evacuation routes, minimise crowding and panic" according to Kane.

These complex models need to be fed with accurate data. Fujitsu is using a dense sensor network off Japan's coast to get real-time data, like wave height. Meanwhile, fast supercomputers and cloud infrastructure allows for resilient access to computing power at all times.

These technologies have already proven valuable in the past, for instance, when the government used cloud computing in Tohoku in 2011 and Kyushu in 2016 to set up platforms for disaster response and to support evacuees with critical information.

Halfway through the project, the organisations are already looking to the future. They intend to extend and apply results of the Kawasaki project "to other regions throughout Japan and overseas areas prone to this type of disaster," Kane says.

The team wants to "evaluate how the technologies could be adapted to improve disaster responses", but also how they could then be integrated into local governments' disaster responses.

If all goes well, the impact will be huge: it will help target government responses; shorten recovery times; save lives; and make communities more resilient.
Main image by United States Navy - CC BY 2.0

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How Japan is predicting tsunamis | GovInsider

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No matter how many times you watch it, the footage of the 2011 Japan earthquake and ensuing tsunami remains a chilling reminder of the immense forces unleashed by natural disasters. This particular catastrophe led to the worst nuclear meltdown since Chernobyl, left over 28,000 people dead or missing, and caused damages as high as US$235 billion.

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Tsunami, or "Harbour Wave," in Japanese, is also referred to (more descriptively), as a seismic sea wave. Tsunami defense is an ongoing battle for the Japanese, so let's take a peek at Japan's engineering solutions to future tsunamis.

Japan's location on the ring of fire, a geologically riotous area of the world, led to a long history of volcanism, earthquakes and tsunamis. Such is the destruction nature has inflicted, and Japan has had to cope in innovative and imaginative ways.

So what are Tsunamis?

Tsunamis are large ocean waves caused by underwater earthquakes, subaquatic or terrestrial landslides or violent volcanic explosions.

Generated by the large, often rapid, massive displacement of oceanic water mass occurs. Most commonly this occurs from subaquatic uplift of the sea floor associated with earthquakes. They have also historically been generated from meteorite impacts, a good example being the mass extinction event at the end of the Cretaceous period.

Why are they so destructive?

Tsunamis often cause more destruction and rack up higher death tolls than the generating source event. Tsunamis are a series of extremely long wavelength waves, and they travel for kilometers with little loss of energy. Once these waves meet shallow waters they become compressed and force water levels much higher, and with much greater energy, than would normally be expected from tidal waves.

Unfortunately, water hugging areas are some of the preferred sites for habitation, understandably. The wave heights and momentum are so great, that their transported energy and high density of buildings and population combined are a "recipe for disaster". Once they hit landfall the power is dissipated with great devastation. Once the waves begin to swap the surrounding coastal areas they also start to "pick up" large objects such as boats, bits of buildings and trees that compound the destructive tendency of the waves.

In the past decade 16 lethal tsunamis, mainly in the Pacific, resulting in more than 6,000 deaths. This is comparable to the death toll of all earthquakes globally for the same period. The 2004 Indian Ocean tsunami claimed more than 230,000 lives and is one of the worst natural disasters in history.

So how is Japan preparing for future inevitable events? Let's take a look.

Early bird catches the worm

Japan's experience led to the development of a strategy of countermeasure, defensive structures and relocation of population centers

Many strategies revolve around moving population centers away from coastal areas or providing as much advanced warning as possible to evacuate. Where this is not possible physical barriers are the only solution, but as we have seen these are not always reliable.

International warning systems have been deployed to attempt to detect tsunami triggering events. This is usually coupled or supplemented with radio and television broadcast and loudspeaker networks to warn the public.

These measures are often useless in the event that the triggering event occurs close to the coast. This may only allow five to ten munites to evacuate. Clearly, for large population centers, this is less than ideal.

Japan has a highly developed public information campaign that informs as many citizens as possible.

Engineering solutions

Japan has tried to employ earthquake engineering to reduce damage onshore. Japan first began researching response measures to Tsunamis in 1896. It has produced ever-more elaborate countermeasures and response plans.

A large part of the Japan's engineering solutions revolves around massive sea walls up to 12 meters tall. This is a response to attempt to protect populated coastal areas. Other solutions include massive floodgates up to 15.5 meters tall with channels to redirect or tamper the incoming waves. Japan has also tested vertical structures, essentially tall platforms for people to stand on above the tsunami maximum height.

Nuclear facilities, in particular, have in recent years tended to be sited far from the coast, with "safe modes" as soon as an earthquake is detected. Evacuation is not an easy option on many low-lying islands. Where structural engineering can be implemented, it can offer options to minimise the death toll after tsunami impact.

Reach for the stars

Researchers have found, using a wave tank, that allowing the water through without obstruction was the best course of action.

"Instead of trying to obstruct the wave, you allow the wave to pass through the structure while causing minimum damage. Large doorways and windows offer a clear path to go through," said Tiziana Rossetto, a reader in earthquake engineering at University College London.

The objective here was to allow for easier reconstruction rather than prevention of damage. It also allowed for occupants to flee to higher ground. Fenestrations are easier to replace than lives after all. Japan's tendency to build in timber also assists where design cannot building design cannot be altered.

"Internal doorways are aligned rather than staggered. If you have staggered doors, the wave gets 'locked' into the house," Rossetto said.

Research has found that houses on piles could also be an answer, but this is not always practicable in all regions.

Practical thinking

Japan has drawn inspiration from other Tsunami impacted areas such as Hawaii. Here the traditionally built concrete buildings that leave the ground floor clear, perhaps as a parking area. This effectively produces a building on stilts.

As like most tsunami prone areas, Japan has developed a mixed strategy which primarily relies on evacuation rather than defense. As seismic detection and preemptive warnings improve, death tolls can and will be reduced.

Infrastructure damage can be repaired rapidly if the building design accommodates strategic designs to either limit or allow easy repair. Defensive structures, such as sea walls, have proved to be ineffective but do provide a psychological boost to the local populace.

Given the need for improvement in detection systems and ineffectiveness of defensive structures, Japan, amongst other affected nations, has tended to place its concentration on detection to save lives. After all, a building can be rebuilt. Lives cannot.
Source: journalistsresource.org

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Japan's Engineering Solutions for Future Tsunami Events

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Tsunami, or "Harbour Wave," in Japanese, is also referred to (more descriptively), as a seismic sea wave. Tsunami defense is an ongoing battle for the Japanese, so let's take a peek at Japan's engineering solutions to future tsunamis. Japan's location on the ring of fire, a geologically riotous area of the world, led to a long history of volcanism, earthquakes and tsunamis.

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A Short History of Tsunami Research and Countermeasures

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A Short History of Tsunami Research and Countermeasures

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Abstract

The tsunami science and engineering began in Japan, the country the most frequently hit by local and distant tsunamis. The gate to the tsunami science was opened in 1896 by a giant local tsunami of the highest run-up height of 38 m that claimed 22,000 lives. The crucial key was a tide record to conclude that this tsunami was generated by a "tsunami earthquake". In 1933, the same area was hit again by another giant tsunami. A total system of tsunami disaster mitigation including 10 "hard" and "soft" countermeasures was proposed. Relocation of dwelling houses to high ground was the major countermeasures. The tsunami forecasting began in 1941. In 1960, the Chilean Tsunami damaged the whole Japanese Pacific coast. The height of this tsunami was 5-6 m at most. The countermeasures were the construction of structures including the tsunami breakwater which was the first one in the world. Since the late 1970s, tsunami numerical simulation was developed in Japan and refined to become the UNESCO standard scheme that was transformed to 22 different countries. In 1983, photos and videos of a tsunami in the Japan Sea revealed many faces of tsunami such as soliton fission and edge bores. The 1993 tsunami devastated a town protected by seawalls 4.5 m high. This experience introduced again the idea of comprehensive countermeasures, consisted of defense structure, tsunami-resistant town development and evacuation based on warning.

Keywords: hazard mitigation, numerical simulation, coastal dikes, comprehensive counter-measures

1. Introduction

The 2004 Sumatra Earthquake and Indian Ocean Tsunami gave us a vivid description of menace of major tsunamis. It also suggested that tsunami science and engineering were inevitable to save human society, industries, and natural environment.

An answer can be found in Japan. Japan is the country the most frequently hit by tsunamis in the world. The experiences are well documented and are continued as the local legends. In 1896, the tsunami science started when the Meiji Great Sanriku Tsunami claimed 22,000 lives. An idea of comprehensive countermeasures was officially introduced after the 1933 Showa Great Sanriku Tsunami. The major works taken after this tsunami, however, were the relocation of dwelling houses to high ground and tsunami forecasting that started in 1941. The 1960 Chilean Tsunami opened the way to the tsunami engineering by elaborating coastal structures for tsunami defense. The 1983 Japan Sea Earthquake Tsunami that occurred during a fine daytime cleared the veil of actual tsunamis. The 1993 Hokkaido Nansei-Oki Earthquake Tsunami led to the practical comprehensive tsunami disaster prevention used at present, in which three components, defense structures, tsunami-resistant town development and evacuation based on warning are combined.

The present paper briefs the history of tsunami research in Japan that supports countermeasures.

2. Before the 1933 Showa Great Sanriku Tsunami

On December 23rd, 1854, the Ansei-Tokai Earthquake occurred at the east side of the Kii Peninsula. On the next day, the Ansei-Nankai Earthquake followed at the west side of the Peninsula. The two earthquakes generated tsunamis that gave heavy damages in the wide area. The height of tsunami was 5 m on an average with locally high value of 10 m. After this tsunami, a coastal dike was built at Hiro village in Wakayama Prefecture at the private expense of a local influential person who became world-widely well known as the hero of "The Fire of Rice Sheaves", a story used in the public education after the 2004 Indian Ocean Tsunami. The construction of coastal dike was quite rare before 1960.

At night on June 15th, 1896, the Meiji Great Sanriku Tsunami hit the pacific coast of the north-eastern Japan, called as the Sanriku Region. The highest tsunami run-up height was 38 m at Ryori Shirahama in Iwate Prefecture. The earthquake was a typical "tsunami earthquake" that had negligibly weak ground shaking, and therefore, no residents tried to evacuate. This resulted in the death toll of 22,000. The economic damage amounted to about 10% of the national budget of those days. After this tsunami, several villages were relocated to high ground at private expenses of individual person or village leaders.

A research group of earthquake, the Council on Earthquake Disaster Prevention (CEDP) of the Ministry of Education had been established 5 years ago, after the 1891 Nobi Earthquake. In an article about the 1896 Meiji-Sanriku event published by the CEDP, earthquake was mentioned as one of forerunning phenomena of tsunami. After 1896, there was a hot academic debate about the generation mechanism of this tsunami. Because of the extremely weak ground shaking, many researchers doubted an earthquake but underwater eruption or landslide as the origin of the tsunami. The key to the solution was the tide records showing quite a long wave period. Only the large fault motion could explain the generation of such a long wave. In around 1910, researchers understood that a fault motion of earthquake was the cause of tsunami.

After the 1923 Kanto Earthquake that devastated the Tokyo Area, the central government fully led the restoration of the metropolis. At the same time, the central government and academic society participated in drafting countermeasures against earthquake and tsunami. The 1933 Showa Great Sanriku Tsunami was the first major tsunami under the modern knowledge and the modern system.

3. Age of the empirical total tsunami-mitigation from 1933 to 1960

In the early morning on March 3rd, 1933, 37 years after the Meiji event, another major tsunami struck the Sanriku Region. The maximum run-up height was 29 m at Ryori Shirahama. Most of coastal villages on the Sanriku Region suffered devastating damages again. Because the ground shaking was strong this time, many residents were awaken and evacuated to high ground; however, the death toll reached 3,000.

The CEDP proposed a total system of tsunami disaster mitigation three months later. They listed the following 10 countermeasures with comments:

Relocation of dwelling houses to high ground: This is the best measure against tsunami.

Coastal dikes: Dikes against tsunamis may become too large, and financially impractical.

Tsunami control forests: Vegetations may damp the power of tsunamis.

Seawalls: These could be effective for smaller tsunamis.

Tsunami-resistant areas: If the tsunami height is not so high in a busy quarter, solid concrete buildings are to be built in the front line of the area.

Buffer zone: Dammed by structures, a tsunami inevitably increases its height. In order to receive the flooding thus amplified, rivers and low-lands are to be designated as buffer zone to be sacrificed.

Evacuation routes: Roads to safe high ground are required for every village.

Tsunami watch: Because it takes 20 minutes for a tsunami to arrive at the Sanriku coast, we may detect an approaching tsunami and prepare for it.

Tsunami evacuation: The aged, children and weak should be evacuated to safe higher ground where they could wait for about one hour. Ships more than a few hundred meters offshore, should move farther offshore.

Memorial events: Holding memorial services, erecting monuments, etc. may help keep events alive in people's mind.

This idea proposed by researchers who worked in the field survey after the 1933 tsunami covers major necessary items in the tsunami prevention. It revived in 1997. See Section 7.

The central government made the restoration plan based on the above proposal. The basic policy was that cities could be restored at the original location surrounded by sea walls but the tsunami-resistant areas and buffer zones should be prepared, and fishing villages should be basically relocated to high ground.

In 1941, a tsunami warning organization was founded for the Sanriku coast. A tsunami forecasting chart was drafted empirically. By the Meteorological Business Act enacted in 1952, the forecasting system was made to cover the whole coast of Japan.

4. Impact of the 1960 Chilean Tsunami

4.1. Chilean Tsunami and research of far-field tsunamis

On May 23rd, 1960 (in Japanese local time), an earthquake occurred off Chilean coast. The tsunami generated by the earthquake attacked the Japanese coast on the next morning. Coastal residents in Japan did not feel any ground shaking. The Japan Metrological Agency did not issue a tsunami warning. Thus, the residents were suddenly attacked by the tsunami. Among the Japanese Pacific coast from Hokkaido to Okinawa, the Sanriku Region was the most seriously damaged. The economic damage was 2.2% of the national budget of those days.

The wave period of the 1960 Chilean Tsunami was from 40 minutes to 1 hour, longer than that of near-field tsunamis that was usually 5 to 20 minutes. Its initial profile in the direction to Japan had the wave length longer than 700 km. Even if short components were included in the initial profile, they were more easily scattered by or trapped around islands and sea mounts during the travel over the Pacific Ocean. In addition, short components retarded due to dispersion effect and then long components arrived first.

The tsunami height, 3 to 6 m, was not so high in comparison of such near-field tsunami as the Meiji and Showa Tsunamis.

In order to judge whether the dispersion effect is non-negligible for a far-field tsunami or not, Kajiura theoretically introduced a criterion. On assuming that an initial waveform is simply parabolic or rectangular, the non-dispersive theory, that is, a linear long wave theory is valid if (6 h/R) 1/3( a/ h) ≥ 4 is satisfied, where h is the water depth, a the horizontal scale of a tsunami source in the direction of propagation and R the distance to the tsunami source. Judged with this criterion, the linear long wave theory including the Coriolis force and dispersion effect expressed with longitude-latitude coordinates is used for the Chilean Tsunami. Imamura et al. numerically simulated the Chilean tsunami with this conclusion.

Kajiura also discussed the energy transfer from the sea bottom to the water in relation to the duration of the bottom movement. If the duration is less than several minutes, the deformation may be considered to be abrupt as far as the tsunami is concerned. However, if the movement is completed in a few second, the energy transferred to the compressional water waves might be larger than the tsunami energy.

His theoretical results are broadly known as the basis of the current tsunami research.

4.2. Chilean Tsunami countermeasures

Shore protection works started in 1950 and were legally authorized under the Seashore Act enacted in 1956. The Act stipulated to embody "the Standards on Construction of Shore Protection Facilities" that worked out in 1958.

In 1959, the Ise Bay typhoon generated a storm surge with the amplitude of 3.5 m at Nagoya port. This storm surge yielded the most serious damages to Nagoya area. This resulted in the death toll of 5,000 and the economic damage of about 9% of the national budget. Coastal embankments made of soil with solid covers only on the seaside surface were completely washed away by overflowing sea water. After this experience, the design standard was revised. Three surfaces (seaward slope, landward slope and crown) of soil embankment should be armored by concrete.

By the Chilean Tsunami, serious damage occurred in the areas that had been believed safe for the past near-field tsunamis. A good example is the area at the bottom of the Ofunato Bay, Iwate Prefecture. This area was hazardless for the past near-field tsunami and was being developed as the industrial and urbanized areas. The long Ofunato Bay became resonant to long wave period of the Chilean Tsunami, producing the largest inundation at the bottom of the bay. The response of bays in the Sanriku Region to the near- and far-field tsunamis was first cited by Watanabe. shows the distinct difference in amplification characteristics between the near-field tsunami (the 1933 event, white circles) and the far-field tsunami (the 1960 Chilean Tsunami, black circles).

Major defense countermeasures after this tsunami consisted mainly of the construction of seawalls and coastal dikes, because the tsunami height was 5-6 m at most. Seawalls were made of concrete and coastal dikes had front, top and back covered with concrete, applying the experience of the Ise Bay typhoon.

It should be mentioned that the first tsunami breakwater was constructed at the mouth of the Ofunato Bay, where the maximum water depth was 38 m. The effect of this breakwater was investigated through numerical simulation. This was the first stage of computer in the tsunami science and engineering.

In addition, it should also be mentioned that an international cooperation of tsunami warning was started after the Chilean Tsunami.

In 1968 when all urgent Chilean Tsunami defense countermeasures were completed, the Tokachi-Oki Earthquake Tsunami struck Hokkaido and Sanriku Region. Fortunately, its tsunami height was not higher than the crown height of just completed structures, and there were no damages. But unfortunately, many person including coastal residents became to believe that there would be no threat of tsunami in the future, forgetting such huge tsunamis as the Meiji and Showa events.

5. Development of numerical simulation and the TIME project

Mansinha and Smylie developed a way to calculate the initial profile of a tsunami from fault parameters in 1971. With this initial condition, a numerical tsunami simulation can be started, but the simulation should cover a wide area and be continued for a long time. Progress in the ability of computer since late 1970s assisted the development of tsunami numerical simulation.

In order to obtain reliable solutions, a simulation should be carried out without any instability and within allowable numerical errors. The stability is ensured by the CFL (Courant-Friedrichs-Lewy) condition that the artificially introduced propagation velocity Δx/Δt should not be smaller than the physical wave celerity of long waves.

In 1982, Goto and Ogawa proposed a numerical method to solve a near-field tsunami from its source to the final run-up on land with the hydrodynamic wave equations in the Eulerian description. They used the linear long wave theory in the deep sea and the shallow-water wave theory in the shallow sea and on land. Their difference equations assume the staggered grid in space with the upwind scheme for the convection term and the leap-frog explicit scheme in time. A moving boundary condition necessarily introduced because of the Eulerian description is another source of instability and numerical errors.

The conditions to limit numerical errors in the Goto-Ogawa scheme are given by Shuto et al. and more thoroughly by Imamura and Goto in relation to local wave length, by Goto and Shuto in relation to the moving boundary condition as well as by Fujima and Shigemura in relation to the local bottom topography.

This scheme is used as the basis of the JMA tsunami numerical forecasting that began in 1999.

Aida introduced two measures, K and κ, in order to judge whether or not a simulation gives satisfactory run-up heights. The measure K is a geometric mean of the ratio of the measured run-up height to the computed, and κ is the corresponding standard deviation. If K falls between 1.2 and 0.8 and κ is less than 1.4, the simulation is judged satisfactorily carried out.

During the IDNDR (International Decade for Natural Disaster Reduction) in 1990s, the tsunami committee of IUGG (International Union of Geodesy and Geophysics) and IOC/UNESCO carried out the TIME (Tsunami Inundation Modeling Exchange) project, by which the Goto-Ogawa's TUNAMI (Tohoku University's Numerical Analysis Model for Inundation) code had been transferred to organizations and countries that needed the numerical technique. The TIME project is still working under the supervision of Prof. Imamura, Tohoku University. The code was transferred to 43 organizations in 22 countries. It is used to predict tsunami damages and to produce hazard maps.

6. The 1983 Japan Sea Earthquake Tsunami

Just at noon, on May 26th, 1983, an earthquake occurred in the Japan Sea. It was a quite fine day, without wind and wind waves. In the Japan Sea, the tidal range is small. Under these conditions, if there were some abnormal sea phenomena, all of them were caused by the tsunami. Many persons witnessed the tsunami, recorded it by photos and videos. These data were energetically collected and analyzed to reveal the true face of the tsunami.

The two facts gave impact to the tsunami research. One is the reliability of tide records and the other is necessity of the dispersion terms that are neglected in the analysis of near-field tsunamis regarded as a matter of course.

Tide gauges are designed to cut such short period oscillation as wind waves, the wave height of which is much bigger than that of tide. To avoid this disturbance, installed is a hydraulic filter consisted of a narrow and long conduit pipe. This hydraulic filter also acted to reduce much the tsunami records of near-shore origin. Satake et al. conducted a thorough survey of all the tide gauge stations in Japan and proposed the way to obtain the true tsunami from the filtered tide record. shows the comparisons of the original tide gage records (solid lines) and the corrected waveforms (dotted lines). Fortunately, in the case of the 1960 Chilean Tsunami, this hydraulic filter was not effective due to the long wave period of the far-field tsunami.

Another impact was the generation and development of a train of short waves at the tsunami front. The wave period of each wave is nearly 10 seconds, similar to wind waves. This phenomenon, so-called "soliton fission" was observed and recorded on a video. In the linear long wave theory and the shallow-water equations used in the tsunami numerical simulation, the vertical acceleration of water particle is assumed to be negligible. To include the effect of curvature of water particle path, a higher-order approximation is necessary, such as the Peregrine equation, the Goto equation and the Madsen-Sørensen equation. Iwase et al. and Iwase et al. concluded that the integrated Peregrine equation or Madsen-Sørensen equation was appropriate for tsunami numerical simulation. Shigihara and Fujima showed the characteristics of several schemes theoretically and recommended an implicit scheme to solve the dispersive long wave equations without any instability.

7. The 1993 Hokkaido Nansei-Oki Earthquake Tsunami and the modern comprehensive disaster prevention

7.1. Revival of the comprehensive counter-measure planning

At night on July 12th, 1993, an earthquake off west coast of Hokkaido generated a tsunami. The southernmost area of Okushiri Island was completely devastated by the tsunami, even though the area was protected by seawalls constructed after the 1983 Japan Sea Earthquake Tsunami. The crown height of seawalls was 4.5 m above sea water level, and the tsunami height was estimated to be over 11 m. This fact called for serious reflection to the conventional method after 1960 that relied mainly on structures.

In 1997, "A Guidance on Reinforcement of Tsunami Disaster Prevention Countermeasures in Local Disaster Prevention Planning" was agreed by National Land Agency and other six government offices concerned tsunami disaster prevention planning. There are two points to be mentioned.

The first is the selection of the design tsunami. One candidate is the largest past tsunami from which credible materials can be obtained, and another is the possible tsunamis caused by the largest earthquake that can be supposed to occur based on present knowledge and science. After comparing both tsunamis, one with the higher water level on coast is selected as the standard tsunami to ensure safety insofar as possible.

The second is the combination of three components; defense structure, tsunami-resistant town development and evacuation based on warning, in an improved and revised form of those proposed by CEDP in 1933.

7.2. 2D/3D hybrid simulation

The highest run-up was found at the bottom of a narrow valley on the west coast of Okushiri Island. At the entrance of the valley 50 m wide, the tsunami trace height was about 22 m, and the maximum run-up 31 m high was marked at a horizontal distance 50 m from the entrance. In this case, it is obvious that the assumption of long waves is no longer valid.

This accelerates the introduction of 2D/3D hybrid simulation; two-dimensional (2D) long wave equations for wide areas and three dimensional (3D) original wave equations for the area where vertical acceleration should be fully taken into consideration. If applied to the case of Okushiri Island, the two-dimensional simulation outside the valley is continued to the three-dimensional simulation in the valley in the neighborhood of the valley entrance.

The method of Fujima et al. and the STOC (Storm surge and Tsunami in Oceans and Coastal areas) code developed by Tomita et al. are typical 2D/3D hybrid simulation. Not only in run-up simulation but also in computation to simulate the deformation and destruction of structure, the idea of 2D/3D hybrid is now used enthusiastically to develop new numerical methods such as SPH (Smoothed Particle Hydrodynamics), DEM (Discrete Element Method), and so on.

8. Other research topics

8.1. Tsunami hazard map and CG animation in public education

In order to make coastal residents recognize the tsunami risk, a useful means is tsunami hazard maps for the past tsunamis and the possible tsunamis in future. After the 1990s, many local governments have been publishing tsunami hazard maps, prepared with the numerical methods described above.

Cabinet Office et al. published "A Manual of Tsunami and Storm Surge Hazard Map" in 2004. This manual recommends hazard map not only for residents but also for companies and fishermen.

Katada et al. introduced "moving hazard maps" in which every resident's action is expressed as the movement of dot, being connected with the motion of the expected tsunami. This gives a clear image of quick evacuation that can save many lives.

One of quite powerful means in public education is three-dimensional CG animations. Many coastal residents who know a huge tsunami in the past only as a tale become to recognize the natural threat and prepare for it at their own initiative.

8.2. Damage assessment and large scale hydraulic experiment

A rough estimate of damage caused by the past tsunamis was given in terms of tsunami intensity. In order to obtain more detailed estimates, knowledge based upon theoretical and experimental consideration is required.

For example, damage to houses is caused not only by tsunami force but also by impact of drifted lumbers and boats. Matsutomi obtained a formula to evaluate the impact of lumbers as a result of large scale experiments.

After the 2004 Indian Ocean Tsunami, many examples were collected for coastal forests that might damp the tsunami power. In case of Japan, limit and effectiveness of pine forests is given. Harada and Imamura introduced an equation to assess more quantitatively and be applicable to other kind of forests.

Large scale hydraulic experiments are being carried out in many institutes and laboratories. Arikawa et al. conducted the experiments on deformation and destruction of a concrete slab and a framework of steel materials using their prototype wave channel. Prior to Arikawa's experiments, Asakura et al. carried out experiments on wave force by overflowing tsunamis. Another example is Ikeno et al.'s work that concerns the wave force of soliton on land. Interesting is a human-related hydraulic experiment. Nishihata et al. measured the walking ability in an open channel flow, and discussed the possibility of evacuation if a man is caught by water flow.

8.3. Tsunami archeology

After the 1980s, investigation on tsunami deposit was started. Historical literatures tell us the events only in recent 1,000 years. With geological data, we can know events in prehistoric age. Sawai et al. succeeded to excavate geologically recorded tsunamis during the past 5,500 years in eastern Hokkaido. This technique is being applied in countries where tsunami occurrence is rare and no documents are available.

8.4. Initial profile

The biggest problem we have to solve in the near future is the detailed profile of a tsunami when it is born.

When seismological data were not available, the inversion propagation method was used to determine the source area and rough estimate of the distribution of vertical displacement. For example, see Hatori.

In case of the 1983 Japan Sea Earthquake Tsunami, Tanaka et al. obtained a profile with the Mansinha-Smylie method from fault parameters. The highest vertical rise was 1.5 m (). Aida carried out tsunami simulation and found that this rise was not enough to explain the tsunami measured and observed along the shore. After several trials, he concluded that the highest rise of 4 m () was necessary to simulate well the measured data.

When the Mansinha-Smylie is used, it is assumed that the fault motion is homogeneous in a fault plane. Satake introduced an inversion method to estimate heterogeneous fault motion, by using tide records. This idea, if combined with the asperity model in seismology, may become a good tool in estimating the initial tsunami profile of large fault movement.

For the further development, inevitable is the accumulation of tsunami records near the tsunami source. The 2003 Tokachi-Oki Earthquake Tsunami was recorded by a tsunami gauge of pressure type just in the source area, as the first case of the tsunami birth. On November 5th, 2004, an earthquake occurred off Kii Peninsula. A tsunami was generated and recorded on a GPS tsunami gauge installed at the water depth of 100 m, 23 km offshore. The computed tsunami with the initial profile estimated by the Mansinha-Smylie method agreed very well with the recorded.

9. Concluding remarks

So many vivid videos and data were taken in 2004 Indian Ocean Tsunami. Those gave tsunami researchers various suggestions. However, the researchers who are going to use data of Indian Ocean Tsunami often face difficulties. Because some videos recorded the local event occurred nearby video-men, and those do not give a total information of the tsunami. In addition, there are some areas where accurate chart and map are not available.

Among recent tsunamis, the 1983 Japan Sea Earthquake Tsunami is the treasure house of actual faces of tsunami. In the 1983 event, several tsunami features were looked down from hills and airplanes, and they were recorded in videos and photos. Most of them are vividly shown in a video edited and published by NHK (Japan Broadcasting Corporation, Japan).

Both the 1983 Japan Sea Earthquake Tsunami and the 1993 Hokkaido Nansei-Oki Earthquake Tsunami were surveyed very accurately and in details. The latter was used as the data for an international bench mark test, in which many modelers competed to show the superiority of their numerical model. In order to support such competition, there is other necessary condition, that is, good charts and good maps are extremely important. Both are often lacked in many developing countries. However, in Japan, the Hydrographic Department of the Japan Coast Guard completed detailed bathymetric maps after the 1983 event. Accurate land maps are available from the Geographic Survey Institute.

Tsunami research has been developing in Japan, because the country suffers tsunami disaster frequently in comparison with other countries. That is why the tsunami research is of great importance in Japan. Basic materials such as bathymetric charts for the research easily obtained, and the seed and hint of the research can be found in well-filed documents and records.

References

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A short history of tsunami research and countermeasures in Japan

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The tsunami science and engineering began in Japan, the country the most frequently hit by local and distant tsunamis. The gate to the tsunami science was opened in 1896 by a giant local tsunami of the highest run-up height of 38 m that claimed 22,000 ...

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Five years ago, a magnitude 9.0 earthquake occurred 200km off the east coast of Japan, causing a devastating tsunami. The resulting waves affected 2,000km of coastline, killed some 18,000 people, destroyed nearly 110,000 buildings and damaged twice that number. It also triggered the meltdown at the Fukushima Daiichi nuclear power plant, which released toxic levels of radiation into the environment and remained the focus of worldwide concern for a long time afterwards.

As we reflect on the terrible destruction of lives and livelihoods wrought by this natural disaster, one question springs to mind: how can we better protect ourselves from the next one?

After all, this was not the first such disaster to hit Japan. For example, the 1896 and 1933 Sanriku earthquakes - which reached magnitudes of 8.5 and 8.4 respectively - also caused deadly tsunamis. For that reason, Japan had already introduced a number of defences prior to 2011. Tsunami barriers were constructed both on and offshore, trees were planted along the coastline, vertical evacuation buildings were built to the highest standards and regular evacuation training was introduced.

But the sheer force of the 2011 tsunami took many by surprise. Most of the protective measures were designed to cope with magnitude 7.4 to 8.0 earthquakes, which occur every few decades in the region. This planning failure was partly due to the limited amount of recorded data, which only spans back 40 to 50 years and contains uncertainties about the location and magnitude of previous mega-earthquakes.

To improve warning systems and build effective defences, we need a detailed understanding of how the tsunami gathers height as it nears the shoreline, and how this affects the damage caused. As soon as the major search and rescue operation was completed, the Tohoku Earthquake Tsunami Joint Survey Group - made up of natural scientists and engineers from 63 universities - set out to gather this information.

Damage is done

The group's measurements confirmed that when the first wave hit the coast, it was largest at the point nearest to the earthquake's epicentre, as expected. But the shape and height of the coastline and seabed affected how far the tsunami spread inland, and to what depth. For instance, the low-lying southern part of the Tohoku coast experienced the worst flooding, with sea water reaching more than 5km inland.

By contrast, on the more northerly Sanriku coast the tsunami's energy was concentrated into deep bays where water levels rose as high as 40m, damaging human settlements on mountain sides rather than ranging far inland.

The effectiveness of defences varied along the coastline too. Tsunami barriers worked in some places but not in others. Breakwaters and seawalls, which were built to protect from storm surges and ocean waves, were completely or partially destroyed depending on where they were. The tsunami also overran coastal dikes and river embankments.

Kimimasa Mayama/Epa

Many structures could not withstand the force of the tsunamis, or the damage caused by drifting vessels and wood debris. The ground liquefied and scour holes developed near foundations, causing the collapse of many buildings. Roughly two-thirds of the protective coastal forests were lost.

The post-tsunami survey and later research gathered detailed data about the causes and extent of the damage. This information can be used to reduce uncertainties when it comes to forecasting future events of this size. Thanks to this research, we now know more about the probability of similar earthquakes, have improved numerical models and can make better predictions about building failures. All of this will enhance the design and construction standards in Japan, and other countries that are prone to tsunamis.

Making a recovery

Before the end of 2011, the Japanese parliament had passed laws to establish "tsunami-safe cities". This involved enhancing research and education, evacuation training and measures to prevent or mitigate the effect of tsunamis in the long term. The government also committed 25.5 trillion yen (£158bn) toward an intense, five-year period of rebuilding.

Next, the Reconstruction Design Council presented a plan to rebuild along Tohoku's coast, based on new tsunami risk simulations and studies. The proposed protection was divided into two levels, which correspond to two classes of tsunamis, based on their magnitude and frequency. Level one (L1) are "smaller", low-impact tsunamis that occur once every 10 to 100 years. Level two (L2) are rare, high-impact tsunamis which only happen once in several hundred to 1,000 years.

Structural measures such as seawalls, embankments and tree plantations will be designed and built to defend people and properties against L1 tsunamis. Soft measures such as land use zoning and evacuation plans will be implemented to protect human lives against L2 tsunamis.

A way to go yet

Putting these improvements into practice has taken longer than expected. The main focus is still on rehousing those whose homes were destroyed. At last count, almost 59,000 of the 470,000 people originally displaced are still living in temporary accommodation.

In many locations, the ground level of sites for new houses must be raised before construction can begin. For example, in the port town of Rikuzentakata, the ground level was raised by about 10m, and two protective seawalls of 3m and 12.5m high are being built. Elsewhere, private houses will be relocated to higher ground, areas behind protective structures will be elevated and forests planted. The Miyagi prefecture proposes to refortify the coast with a tall seawall several kilometres long for tsunami protection.

All of these measures take time, and many have divided opinion: some inhabitants do not want to move from the coastal strip, but neither do they want their view infringed by a tall wall.

Although the scientific research carried out after the 2011 tsunami will help to protect Japan from future disasters, there will always be shades of uncertainty. After all, it is unlikely that every possible combination of events has been predicted and accounted for. That's why it is crucial to continue monitoring for early warning signs, evaluating predictive models and building physical defences. Perhaps most importantly, we need to raise awareness of the risks of coastal living, and ensure that people are prepared to move quickly when the need arises.

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How scientists are helping Japan rebuild after the devastating 2011 tsunami

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Five years ago, a magnitude 9.0 earthquake occurred 200km off the east coast of Japan, causing a devastating tsunami. The resulting waves affected 2,000km of coastline, killed some 18,000 people, destroyed nearly 110,000 buildings and damaged twice that number.

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National Geographic Website

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With the ability to approach shores at 30 miles an hour and rise more than 100 feet high, tsunamis pose a deadly threat to coastal populations. The 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami are two vivid and tragic examples of these waves' destructive power.

The most important step in staying safe during a tsunami-or any natural disaster, for that matter-is to know how vulnerable your area is in the first place. Many local governments map hazard areas and evacuation routes for communities at risk, while the U.S. National Weather Service offers a nationwide map with links to resources.

"Know what your risks are," says Kevin J. Richards, a natural hazards officer for the Hawaii Emergency Management Agency. "What's likely going to impact your home or your area?"

● Know the warning signs of a tsunami: rapidly rising or falling coastal waters, a loud roar from the ocean, or rumblings of an earthquake. "If people along the Indian Ocean coastline on December 26, 2004, were aware of and heeded these natural warnings, fewer people would have died," says Rocky Lopes, administrator of the National Tsunami Hazard Mitigation Program. He adds, "A strong myth is that tsunamis always cause the ocean to recede before [the powerful] waves flood in. In some areas, particularly on islands, water recession may not happen."

● Familiarize yourself with your government's warning system and subscribe to alerts. In the U.S., NOAA Weather Radio is a good resource.

● Map your evacuation route-not just for your home, but work, school or caregivers, or any place else where your family tends to be. Know how to get to safety on foot-roads may not always be feasible.

● Have your evacuation plan ready and rehearsed now. That way, Richards says, "You don't have to think about it. You just go and do it."

● Keep an emergency kit or "go bag" handy at home or in your car. The American Red Cross offers tips for stocking it here, including food, water, and a cell phone with chargers.

● Coordinate with loved ones on reuniting. "What happens when the family has to respond from separate areas?" Richards recommends asking. "How do you eventually come back together?"

● If you're in a tsunami area and there is an earthquake, first drop to the floor, cover your head and neck, and hold on to something stable. If you're in a low-lying area, move inland as soon as possible.

● Listen for official warnings, but also listen and watch for natural signs. "Listen to the authorities, but do not wait for tsunami warnings and evacuation orders," counsels the U.S. site Ready.gov.

● People often mistake the distance they have to go to be safe. "Many people think they've got to go miles," Richards says, "when it might be just right behind Johnny's house." If you're a visitor staying in a tall concrete hotel, he adds, going above the fourth floor likely will be safer than evacuating.

● Stay put in a safe area until an official all-clear is given. The first wave of a tsunami may not be the last or the strongest and the danger can last for hours or even days, according to the National Weather Service.

● Stay clear of damaged or flooded areas and downed power lines.

● Listen for further alerts and instructions about evacuation zones and shelters.

● Use texts and social media to communicate with loved ones, as phone systems are likely to be down or busy. The American Red Cross has a registry where you can list yourself as safe and well.

Follow these common-sense guidelines from the U.S. Centers for Disease Control and Prevention on food and water safety, including using bottled, boiled, or treated water and throwing away perishable foods left unrefrigerated for more than four hours.

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With the ability to approach shores at 30 miles an hour and rise more than 100 feet high, tsunamis pose a deadly threat to coastal populations. The 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami are two vivid and tragic examples of these waves' destructive power.

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How to Build Earthquake Resistant Housing

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How to Build Earthquake Resistant Housing

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Hunker Website

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How to Build Earthquake-Resistant Housing. As earthquakes hit strongly in places as divergent as California, Tennessee, New York, Japan and Brazil, more builders, architects and property owners look for ways to build earthquake-resistant housing. Many construction companies specialize in building these types of structures. While no design can totally prevent earthquake damage, certain building systems can lessen it. Read the tips below for advice on how to build earthquake-resistant housing.

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How to Build Earthquake-Resistant Housing | Hunker

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How to Build Earthquake-Resistant Housing. As earthquakes hit strongly in places as divergent as California, Tennessee, New York, Japan and Brazil, more builders, architects and property owners look for ways to build earthquake-resistant housing. Many construction companies specialize in building these types of structures.

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Hunker Website

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Implementing adaptations to earthquakes can help governments, business owners and individuals prevent loss of life and property damage in areas prone to such disasters. These adaptations range from efforts to secure small household items to the reinforcement of huge structures like bridges and office buildings. Large-scale measures often prove costly, but they have already yielded great benefits in places like Japan.

When earthquakes occur, structural adaptations do much to prevent the damage or destruction of buildings. Encarta indicates that builders reinforce some structures against earthquakes with bracing. Relatively small buildings made of wood prove less susceptible than those constructed of rock-like materials such as concrete. It's possible to enact structural adaptations during construction or to reinforce old buildings. Some newer structures in California and Japan feature a flexible design which causes them to sway during earthquakes rather than collapse, according to Public Radio International.

Homeowners, apartment dwellers and office workers can adapt various indoor items to prevent them from falling long distances. It's possible to brace shelves so that they don't easily fall over in earthquakes, according to Encarta. The U.S. Geological Survey lists additional adaptations such as strapping water heaters to wall studs and putting latches on kitchen cabinets. It also recommends using straps and buckles to anchor electronics and small appliances to surfaces (such as desks and kitchen counters).

Earthquakes sometimes threaten the safety of people in transit, with only airborne vehicles remaining completely safe. The San Francisco Chronicle reported that California's Bay Area established plans in 2008 for retrofitting the subway system to resist earthquakes. Adaptations included compressing the earth surrounding a tunnel and reinforcing some transit buildings and raised tracks. The Golden Gate Bridge, Highway and Transportation District indicates that after an earthquake, authorities improved the Golden Gate Bridge by installing additional bracing, boosting the strength of bridge foundations and adding expansion joints, among other adaptations.

In regions prone to earthquakes, it also is important to adaptations the storage and transport of toxic or highly flammable materials. Keeping hazardous substances close to the floor helps prevent their release during earthquakes, according to the U.S. Geological Survey. The less distance they have to fall, the less chance that the containers will break open. The USGS also recommends using flexible indoor natural gas lines rather than rigid pipes, which may break in earthquakes and start fires.

About the Author

William Jensen began his writing career in 2007. His work has appeared on various websites, covering currents events, technology and other topics.

Photo Credits

Thinkstock/Comstock/Getty Images

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Implementing adaptations to earthquakes can help governments, business owners and individuals prevent loss of life and property damage in areas prone to such disasters. These adaptations range from efforts to secure small household items to the reinforcement of huge structures like bridges and office buildings.

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Hunker Website

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Earthquakes destroy homes and commercial buildings, taking lives and costing huge amounts in repairs. The development of earthquake engineering hopes to counter this. As the cost of making all structures earthquake resistant would be too high, the government assesses the potential for earthquakes in different regions. Architects design buildings to handle seismic effects, sustaining an acceptable damage level.

The lighter the building, especially toward the top, the more resistant it is against seismic effects. Earthquake protected structures have lightweight roofs and lighter floors, walls and partitions on upper levels. Restrictions in some areas limit the height a buildings can reach, due to deaths caused by falling debris in the past.

Earthquake proof buildings use base isolation to separate the structure from the seismic waves. This means that the base is flexible, made from a material such as rubber, and surrounded by a moat. The base shifts with the wave while the main structure remains steady. The base isolation system consists of two parts: the isolation units that separate the base from the structure and the isolation components that connect the isolation units and the rest of the building.

Some earthquake resistant buildings use steel reinforcements, called reinforced masonry, either embedded into the mortar joints of masonry or inserted into holes and filled with concrete or grout. In California, this practice has been mandatory since the 1933 Long Beach earthquake. An alternative reinforcement method is reinforced concrete. This involves the addition of steel reinforcement bars (rebars) or fibers into concrete, therefore strengthening an otherwise brittle material. Beams, columns, floors and bridges use this method.

Prestressing requires deliberately creating irreversible stress points on a building to help it withstand seismic stress. Prestressing can involve pre-compression (using the structure's own weight), pre-tensioning (using high strength tendons) or post-tensioning (using either high strength bonded or unbonded tendons). One type of reinforced concrete is prestressed concrete. Added to beams, floors or bridges, this concrete withstands tension longer than normal reinforced concrete.

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Facts About Earthquake Proof Buildings | Hunker

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Earthquakes destroy homes and commercial buildings, taking lives and costing huge amounts in repairs. The development of earthquake engineering hopes to counter this. As the cost of making all structures earthquake resistant would be too high, the government assesses the potential for earthquakes in different regions.

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Positive and Negative Effects of Earthquakes

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Positive and Negative Effects of Earthquakes

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Sciencing Website

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According to the United States Geological Survey, scientists at the National Earthquake Information Center record more than 20,000 earthquakes each year, and estimate that millions occur globally. Many earthquakes are small and barely noticeable. However, some earthquakes, such as Japan's 2011 earthquake, can unleash devastating amounts of energy, killing thousands of people and destroying large areas of land. Despite this devastation, earthquakes can also have positive benefits for humans.

Measuring small earthquakes allows geologists to study areas underground. Geologists can measure the way that the vibrations of earthquakes travel and make inferences about the type of material the vibrations pass through. Geologists can find water aquifers, oil and natural gas deposits and other important resources based on information they gain from earthquakes. Geologists can also measure the size and extent of these resources to better understand exactly how large the deposits are.

Earthquakes are the earth's way of releasing energy stored in plate tectonics as they move. If plate tectonics could not move, the world would look dramatically different, with no mountains and distinctly smaller oceans. As plate tectonics move, it naturally cycles materials from the mantle of the earth. The seafloor that new material creates harbors thousands of species of plants and animals, which themselves play important roles in the human ecosystem by doing things like absorbing carbon dioxide and releasing oxygen through photosynthesis. Without the movement that allows earthquakes, none of this could occur on the earth.

Major earthquakes can kill thousands of people. The earthquake off the coast of Indonesia in 2008 released a tsunami that killed more than 280,000 people. The 2010 earthquake in Haiti killed more than 230,000 people. Earthquakes can be especially deadly for developing areas because they often do not have stringent construction standards and technology that would protect people.

In addition to the death toll, earthquakes can cost billions of dollars in damage to repair. The 2011 Japanese earthquake will cost approximately $232 billion dollars to repair. The damage the 2004 Indonesian earthquake wrought is estimated at $8.4 billion dollars. In addition to physical damage, the destroyed infrastructure may cause the economies of the affected areas to suffer. Again, areas with poor building standards suffer the most, although as evidenced by the case of Japan, earthquakes can devastate developed economies as well.

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Positive and Negative Effects of Earthquakes

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According to the United States Geological Survey, scientists at the National Earthquake Information Center record more than 20,000 earthquakes each year, and estimate that millions occur globally. Many earthquakes are small and barely noticeable. However, some earthquakes, such as Japan's 2011 earthquake, can unleash devastating amounts of energy, killing thousands of people and destroying large areas of land.

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Website

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The main effects of earthquakes are-

1.Deformed ground surface

2.Damage to man made structures

3.Damage to towns and cities

4.Loss of human and animal life

5.Devastating fires

6.Landslides

7.Flash floods

8.Tsunamis

9.Seiche

10.Sandblows

11.Faults

The main damage is caused to human, animal life and damage to

properties.

Earthquakes cause a lot of devastation, thereby causing great

loss of life and property.

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What are the effects of earthquakes - Answers

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The main effects of earthquakes are- 1.Deformed ground surface 2.Damage to man made structures 3.Damage to towns and cities 4.Loss of human and animal life 5.Devastating fires 6.Landslides 7.Flash floods 8.Tsunamis 9.Seiche 10.Sandblows 11.Faults The main damage is caused to human, animal life and damage to properties.

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ABC Science Website

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Earthquakes, Tsunamis & Volcanoes " Ask a Real Expert " Ask an expert

" previous question | all | next question "

Q6: Earthquakes have always been part of the earth's geology. What are the positive effects of earthquakes? Would mankind have evolved on earth without its restless tectonic activity?
Submitted by Michael Chester

A: Earthquakes are very useful to humans because they provide a picture of whats going on underground. This can make oil and gas extraction more efficient, and allows scientists to monitor the progress of water during geothermal energy extraction.

They also tell you what is happening in the structure of the earth, for example, magma chambers, and allow scientists to monitor volcanoes and the threat of eruption.

Earthquakes can also tell us about the internal structure of the Earth. By measuring the time it takes the seismic waves to travel through the Earth we can map out the structure of the Earth down to the core.

On a global scale, earthquakes are just a symptom of the movements of the plates going on all the time, and they occur because the material at the surface at the earth is changing due to convection within the Earths mantle mountains are being created, minerals from below are being brought up and new sea floors are being made.

Tectonic activity is essential to sustaining life on Earth. Matter is constantly being recycled between the atmosphere and the crust. We have continents because of tectonic activity. Mid ocean ridges support a huge amount of life, and may have been important in the origin of life, and the atmosphere is reliant on volcanic eruptions for its composition.

- Clive Colins, seismologist, Geoscience Australia

" previous question | all | next question "

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Earthquakes - Ask a Real Expert - Ask an expert - The Lab - Australian Broadcasting Corporation's Gateway to Science

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Earthquakes, Tsunamis & Volcanoes " Ask a Real Expert " Ask an expert " previous question | all | next question " Q6: Earthquakes have always been part of the earth's geology. What are the positive effects of earthquakes? Would mankind have evolved on earth without its restless tectonic activity?

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Kids Discover Website

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Gain instant access to this beautifully designed Unit on Earthquakes, where kids will learn all about How Earthquakes Work, Measuring and Predicting Earthquakes, Famous Earthquakes, and more. Access 3 different reading levels perfect for Grades 3-8. Written by subject experts, aligns with standards.

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Website

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Introduction

The magnitude 9.0 Japan's Tohoku Earthquake occurred at 14:46 local time on Friday, 11 March 2011, 125 km east coast of Honshu and 380 km far from Tokyo and rattled the large parts of Japan and some part of east China and Russia with 30 km depth of the hypocenter ( 1). This earthquake that lasted approximately 3 minutes (170 seconds) caused a 130 km long by 159 km wide rupture zone on the pacific plate subduction zone and followed by a huge tsunami with more than 40 meter waves. The destructive aftermaths of this incident made an irreparable disaster not only for the Japan, but also for the whole world because except for the enormous death toll and debris, the damages of nuclear power plants were a hazardous unexpected tragedy.

Casualties and damages

According to the report of the Japanese National Police Agency, 15854 dead, 3167 missing and 26992 injured across twenty prefectures are the result of this devastating earthquake and tsunami which ruined more than 125000 buildings. Moreover, it caused long blackouts for more than 4.4 million buildings and left 1.5 million buildings out of water for days ( 2), also large fires were triggered one after another even for weeks after the main quake. Explosion and demolition of the Fukushima I Nuclear Power Plant (Fukushima Daiichi), which generated radioactive contamination near the plant's area with irreversible damages to the environment, was one the most significant issues of this catastrophe and ranked 7 (the most sever level for nuclear power plant) based on the International Nuclear Event Scale, similar to the Chernobyl disaster on 26 April 1986 ( 3). Therefore, it is not strange to consider to this earthquake as the most important destructive seismic event of the beginning of the twenty first century in the advanced industrial world.

Losses intensified by hit of the tsunami as the statistics shows it was more fatal () and also more buildings destroyed by its strike; However, the quake was the main cause of the partial damage of buildings ( 4). manifests the building losses distribution through affected areas and reveals the relative impact of the earthquake vs. tsunami in each prefecture of Japan ( 4).

Seismology and Seismic History

This mega thrust earthquake is categorized as a great earthquake with the magnitude more than 8 in scientific seismological classification ( 5). Over 1000 aftershocks, some of which were larger than the recent catastrophic earthquakes in Iran such as Bam, Iran 2003, hit the area since the main shock. Regardless of the consequent tsunami, the Tohoku Sendai Earthquake (2011) is the largest recorded earthquake in the history of Japan in terms of magnitude while the territory of Japan is known by numerous and critical earthquakes. There are two momentous calamitous earthquakes in history of Japan: The great Kanto earthquake with magnitude of 7.9 on 1 September 1923 which destroyed Tokyo and Yokohama rigorously by the severe quake and subsequent fires and caused more than 143000 deaths ( 6, 7); and the Kobe earthquake (also known as Hanshin- Awaji earthquake) with magnitude of 6.9 on 17 January 1995 that left more than 6400 demises ( 6, 8). The Kanto incident is still the deadliest earthquake in Japanese history and the Kobe earthquake was the most costly natural disaster of the world since Tohoku Earthquake 2011 ( 9).

Methodology

Japan crisis management system

Japan has an overall population of 127 million and is one of the most densely populated countries in the world (340 persons per Km), where the population highly concentrated around Tokyo ( 6). This earthquake-prone country as a pioneer in crisis management has a comprehensive plan for preparing against disasters, consists of the Central Council for Accident Prevention, chaired by Prime Minister, set of cohesive rules for immediate response to all of the unexpected incidents, the advanced research system and the extensive public education about disasters. As the result of this plan, in the case of an accident, people, government officials and rescue departments know exactly what to do while the alarm is sounded, without chaos.

It was after the disastrous Kobe earthquake of 17 January 1995 (M6.9) that crisis management of Japan greatly promoted since the government set up a GIS system and a general computer network. This system contains different subsystems to operate all disaster related functions from prevention before the disaster to damage evaluation after it ( 10). Additionally, the most advanced earthquake and tsunami early warning system of the whole world is installed in Japan during 2003 to 2007, which is one of the main parts of this crisis management system. This warning system had a considerable role in Tohoku 2011 earthquake to reduce losses and save lives. Several Japanese media such NHK channel and also mobile phone networks have the most responsibility of broadcasting the news of early warning system.

In management of the 11 March 2011 crisis, one of the most facilitative factors for emergency managers was proper behavior of people who follow the commands cautiously. In other words, the " social capital" in this country had a significant role in recovery after the incident as people's high respect to roles and moral values and their solidarity prevent them from influx for aid and looting and motivate them to consider the public benefits instead of self-interests.

Response to the disaster

Immediately after the event, The Government of Japan (GOJ) held National Committee for Emergency Management, headed by Prime Minister. The government declared an emergency in effected area and dispatched the Japan Self Defense Forces for rescue operations ( 11). All ministries and departments such as Foreign Ministry, Ministry of Transport and Ministry of Health were involved in this response, also local offices of disaster response in all prefectures begins their operations as their duty was already clear. The Ministry of Health was in charge of preparing suitable vehicles for supplying water and assigning hospitals for remedy of casualties and people who have been exposed to radiation. Ministry of Agriculture, Forestry and Fisheries with Ministry of Finance were responsible for providing food, portable toilet, blanket, radio, gasoil, torch, dry ice and other essential things. By the command of the government, all of the main highways in north of the country were completely occupied for emergency response activities. Besides, the transport systems includes subway, shipping and the Shinkansen bullet train ceased their activity in Sendai and Tokyo instantly after the quake.

Moreover, at the day of event the Government of Japan declared "the state of nuclear emergency" due to the threat posed by reactors in two Fukushima nuclear power plants (I and II) and 140,000 residents within 20 km of the plant evacuated. At 15:36 JST (Japan Standard Time) on 12 March, there was an explosion in the reactor building at Unit 1 in Fukushima Daiichi (I) power plant. At 11:15 JST on 14 March, the explosion of the building surrounding Reactor 3 occurred. An explosion at 06:14 JST on 15 March in Unit 2, damaged the pressure-suppression system. When the disaster began on 11 March 2011, reactor unit 4 was shut down for periodic inspection and all fuel rods had been transferred to the spent fuel pool on an upper floor of the reactor building. On 15 March, an explosion damaged the fourth floor rooftop area of the unit 4 reactor.

Japanese Red Crescent Society (JRC), which had a substantial role in initial relief operations and temporary housing, deployed its teams promptly. JRC performed properly for accommodation of refugees and evacuees in schools, public buildings, and shelters. This society adapted its operations to all other rescue organizations and NGOs, which deployed to the area later.

Construction of temporary housing in quakestricken prefectures was begun 8 days after the event and the first set of buildings was expected to be ready within a month ( 12). In addition to medical aids, therapists and social workers were dispatched to the affected zone by Health ministry and then in coming days the concentration of treatments was shifting to psychotherapy from physical sicknesses. In addition, this Ministry performed required actions in order to control and inhibit infectious diseases and encouraged people to use masks ( 2).

Fire was reported in eight prefectures after the quake. Fire suppression of gas pipeline took a few days and fires in Cosmo Oil Installations and some other refineries lasted 3 days. Generally, the number of fires increased from 44 to 325 in a week, but its growth rate declined. All the fires, which were triggered after the earthquake, were under control of Japanese Police and it can be said that they could prosperously cease and extinguish them ( 13). On the other hand, these fires and breakdown of six out of nine oil factories faced the affected areas with fuel shortage. The gas pipeline repairing operation had a slow progress, too. Therefore, about one million liter gasoline per day had been carried to the damaged areas by tankers and then by cargo train in order to compensate lack of fuel. Low displacement capacity of oil and coal shipments caused delays in delivering fuel loads, which were importing from countries such as South Korea and Russia, to consumers ( 13).

Due to the shutting down of the power plants which were cracked by the quake and tsunami, authorities begun imposing sporadic power cuts nationwide to make up for production losses. Correspondingly, large factories like Toyota and Sony halted their production activities and many citizens in Kanto reduced their power consumption in order to abridge the time of blackouts ( 14).

Nuclear crisis

There are 54 reactors in Japan, but since the tsunami on March 2011 that destroyed Fukushima plant () and triggered the world's worst nuclear crisis in 25 years, the government did not allow to restart any reactor that have undergone maintenance due to public safety ( 15). The first nuclear power plant of Japan was initiated with collaboration of English corporations in 1973, but these kinds of power plants then developed by American technology. All the 11 reactors in Fukushima 1, Fukushima 2, Onagawa and Tokai nuclear power plants automatically safe shut down after the quake; however, arrival of tsunami debris with high waves damaged reactor's cooling systems and eventually, resulted hazardous explosions. This could have been prevented if the designers had estimated the probable maximum altitude of the tides more prudently. The explosion occurred in 4 of the 6 reactors of Fukushima 1 power plant one after another, while the unit 3 reactor was more damaged and more intensively contaminated the surrounding area. A few hours before each of these explosions, authorities warned about the cooling system breakdown, ordered to evacuate neighboring people and tried to drop the pressure of vapors, but in all of them the hydrogen explosion finally happened.

The owner of the Fukushima Plant, The Tokyo Electric Power Company (TEPCO), is accused of mismanagement and hiding the truth about the real damage caused by the disaster at the expense of saving the company ( 16). Moreover, according to reports, it was expected that TEPCO safely shutdown reactors of Fukushima 1 nuclear power plant approximately a month before the 11 March earthquake, but apparently the company avoided this action because of economic issues.

Over 140 thousand residents were evacuated from 20 Km around the Fukushima plant. Radiation penetrated in foods and drinking water in 30 kilometer far from the evacuated area, and authorities inhibited distribution of these polluted foodstuffs ( 13). U.S. Department of Energy announced a wide area beyond 80-kilometer radius around the Fukushima plant is affected by radiation ( 17).

The explosion of Fukushima power plant and its aftermaths aroused public concerns about nuclear energy in Japan and other earthquake prone countries. Consequently, other power plants, which were not resistant to the probable future quakes with magnitude more than 8, ceased they activity gradually sequentially by the command of The Prime Minister. TEPCO shut its last operating nuclear reactor in 26 March 2012 for regular maintenance, leaving just one running reactor supplying Japan's creaking power sector ( 15). Then again, on 10 April 2012 (less than a month later), as the summer arrives, while Japan is going to struggle with electricity shortage, the government planned to restart one of the atomic plants in Kansai after approval its safety ( 18) and faced with people's disagreement.

Furthermore, the nuclear crisis has led to growing opposition against atomic power plants in other countries, particularly in Germany, where thousands of citizens participated in an anti-nuclear demonstration. This disapproval also affected the regional election results unbelievably. In the state of Baden-Wurttemburg, which traditionally had gone with Christian Democratic Union party for 58 years, most of people voted for the Green Party who was against with 17 nuclear reactors in this country ( 19).

Results: Crisis consequences

The 11 March 2011 earthquake had many deleterious environmental impacts that take a long time to recover. Apart from radioactive materials dispersed due to nuclear plant explosions and discharging polluted radioactive water of cooling systems to the sea, the subsequent tsunami induced huge amount of debris contains building materials, broken boats, cars, trees and etc. that cause environmental harmful issues.

Radioactive pollutions and radiations as the most harmful repercussions of the earthquake induced fear and concern among resident. Most evacuees did not return to their home even after the safety of the regions was assured. However, the government tried hard to convince people to return to their homes by checking and promulgation the radiation doses constantly, but just the population of old people gradually increased. Therefore, satisfying young people to come back will be a demanding challenge for the government.

A year after the event, anecdotal evidence suggests that fear of radiation, rather than contamination itself, is triggering stress-related problems among nuclear evacuees ( 20), despite the experts emphasized that the doses are too low to develop cancer. Even in more distant areas, where completely secure, parents do not allow their children to play outside. Although there have been no recorded deaths from radiation in Fukushima, according to the Yomiuri Shimbun newspaper, psychological trauma associated with evacuation, pneumonia and heart disease were much more fatal based on statistics. Therefore, in months after the event, Japanese Red Cross concentrated on mental health issues.

Also, the tsunami had adverse effects on agriculture and requires long-term reconstruction at least for 2 or 3 years. In addition, the fishing industry faced to critical continuing problems. Most reports acknowledged that Japan's food exports could be limited by Japan's current Production and supply shortages, along with boosting food safety concerns and possible long-term radiation threats to its food production, in contrast possibly its need for food imports will increase in future ( 21).

Moreover, since Japan is a country covered by jungles, wooden houses are very prevalent in this country and despite the dropping rate of wood imports in recent decade, due to boom reduction of this kind of homes; the Tohoku earthquake caused a 70% rise in wood import rate by enhancement of the wood demand. This made a competition for wood exporters from different countries such as Australia, America, and China.

One of the important impacts of the Fukushima power plant explosion is its psychological consequences. Regardless of common diseases such as infectious ones that break out after earthquakes, the radioactive contamination permeated to the residential areas where people was living, working and planting brought a ten times fatal disease, which is hopelessness and untruthfulness. People know they should leave anything they had include home and agriculture plant and this lead them to an ambiguous future which is unstable and they should build everything from beginning. The increase in number of suicides in power plant's surrounding areas even far from them and farmers concern about safety of their productions and land even 100 kilometers far from the affected zone prove the strength and influence of this issues.

Japan should also challenge with the problem of enhancing of unemployment. Large number of refugee and evacuees left their home and moved to other cities. Also, workers of car and electronic factories are now jobless by factory closure so they are forced to immigrate ( 22). Japanese government created around 20 thousands of jobs in the emergency measures to combat the effects of the disaster in a month, but the number of the unemployed ones was much more than created jobs ( 23). Additionally, women especially in rural areas, who used to were involved in tough works such as agriculture and fishing, after the disaster have to work in other posts and try different occupations in order to help to family economic. Many of these women take apart in protests against Fukushima power plant issues in Tokyo in October and November 2011. It seems that this earthquake has modified the women life style in affected prefectures as now they have more important roles in family issues and it is big change in an almost traditional male-dominated Japan.

Following the shutting, the Fukushima power plant, on February 2012, the House Foreign Relations Committee off Japan approved to export its nuclear equipment to Vietnam and Jordan. Also Japanese companies signed agreements with India, Bangladesh, and Turkey about construction, operation, and management of nuclear power plants in these countries, despite environment activist's oppositions in recent months against these transactions and their high costs and permanent detriments for humans and earth. Actually, the nuclear power in spite its approximate low costs, have many hazardous disadvantages that the Japan 2011 accident and the Chernobyl 1986 are good samples for this fact. Unfortunately, developing countries do not consider these consequences and endanger the environment and people's lives while Japanese authorities are just accenting their own country's benefits.

Conclusion

In Tohoku earthquake and tsunami of 11 March 2011 despite the unprecedented scale of the quake itself, infrastructures and buildings mostly remained standing and proved the resilience of Japan is planning laws especially in constructions and earthquake technology. Hence, if the earthquake had been the sole problem, then Japan could have claimed for itself a momentous prosperous in planning for the impact of a major earthquake. The reason of Japanese plans failure was the large-scale tsunami, which had higher waves than what was assumed in designing. In addition, the fact that Japanese authorities considered economic benefits more than safety and moral factors exacerbate the situation. Even after the disaster, this country just cared about economic benefits and sought to export its technology to other countries.

However, this disaster was a motivation for people and governments worldwide to replace clean energy with the hazardous one and it was a reminder to decommissioning the old and unsafe operating power plants. Thus, the Metsamor nuclear power plant in Armenia, Iran's neighboring country, is a critical threat in the region with high seismic risk. Governments had to plan long-term and costly solutions to replace the nuclear energy with clean and renewable forms of it with respect to criteria and moral values, not only the benefits.

Although energy issues and management of power plant's crisis was a blind spot in Tohoku disaster management, Japanese social ethics and their manner in dealing with the problem were the most advantageous points. Discipline, maintaining calm, public confidence in managers and scientific management based on the plans helped to improve the situation more quickly (). Long queues of Japanese People for food and facilities instead of chaos, which we mainly consider in developing countries, could be a good proof for other countries that enterprising on educating people about how to act in crisis is very operative and effective in enhancement of disaster management.

The 11 march 2011 earthquake was an alarm for seismologist all over the world, particularly in Tehran as a capital city, to revise their methods and evaluation of estimating the plausible time and magnitude of earthquake. It could be an alarm for us to be more meticulous and cautious about the earthquake hazard as prepared and industrialized Japan with the most modernized technology confronted many extensive troubles, which were out of their predictions. Now we should ask this question "how much we are prepared in an earthquake prone country with a capital located exactly on active faults?"

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Crisis Management of Tohoku; Japan Earthquake and Tsunami, 11 March 2011

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The magnitude 9.0 Japan's Tohoku Earthquake occurred at 14:46 local time on Friday, 11 March 2011, 125 km east coast of Honshu and 380 km far from Tokyo and rattled the large parts of Japan and some part of east China and Russia with 30 km depth of the hypocenter ( 1).

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Science >> Earth Science for Kids

Weather - Hurricanes (Tropical Cyclones)

What is a hurricane?

A hurricane is a large rotating storm with high speed winds that forms over warm waters in tropical areas. Hurricanes have sustained winds of at least 74 miles per hour and an area of low air pressure in the center called the eye.

Different Names for Hurricanes

The scientific name for a hurricane is a tropical cyclone. Tropical cyclones go by different names in different places. In North America and the Caribbean they are called "hurricanes", in the Indian Ocean they are called "cyclones", and in Southeast Asia they are called "typhoons."

How do hurricanes form?

Hurricanes form over the warm ocean water of the tropics. When warm moist air over the water rises, it is replaced by cooler air. The cooler air will then warm and start to rise. This cycle causes huge storm clouds to form. These storm clouds will begin to rotate with the spin of the Earth forming an organized system. If there is enough warm water, the cycle will continue and the storm clouds and wind speeds will grow causing a hurricane to form.

Parts of a Hurricane

Eye - At the center of the hurricane is the eye. The eye is an area of very low air pressure. There are generally no clouds in the eye and the wind is calm. Don't let this fool you, however, the most dangerous part of the storm is at the edge of the eye called the eye wall.

Eye wall - Around the outside of the eye is a wall made up of very heavy clouds. This is the most dangerous part of the hurricane and where the highest speed winds are. The winds at the eye wall can reach speeds of 155 miles per hour.

Rainbands - Hurricanes have large spirally bands of rain called rainbands. These bands can drop huge amounts of rainfall causing flooding when the hurricane hits land.

Diameter - Hurricanes can become huge storms. The diameter of the hurricane is measured from one side to the other. Hurricanes can span a diameter of over 600 miles.

Height - The storm clouds that power hurricanes can become very tall. A powerful hurricane can reach nine miles into the atmosphere.

The structure of a hurricane

Where do tropical cyclones occur?

Tropical cyclones occur over the ocean in areas near the equator. This is because there is plenty of warm water in these areas to allow the storms to form. There are seven major areas in the world that tend to produce tropical cyclones. See the map below.

Locations of tropical cyclones throughout the world

When do hurricanes occur?

Hurricanes that form in the Caribbean and the Atlantic Ocean occur between June 1st and November 30th each year. This is called hurricane season.

Why are hurricanes dangerous?

When hurricanes strike land they can cause huge amounts of damage. Most of the damage is caused by flooding and storm surge. Storm surge is when the ocean level rises at the coastline due to the power of the storm. Hurricanes also cause damage with high speed winds that can blow downtrees and damage homes. Many hurricanes can develop several small tornados as well.

How are they named?

Hurricanes in the Atlantic are named based on a list of names maintained by the World Meteorological Organization. The names go in alphabetical order and the storms are named as they appear. So the first storm of the year will always have a name that starts with the letter "A." There are six lists of names and each year a new list is used.

Categories

Tropical cyclones are categorized according to the speed of sustained winds.

Tropical Depression - 38 mph or less

Tropical Storm - 39 to 73 mph

Hurricane

Category 1 - 74 to 95 mph

Category 2 - 96 to 110 mph

Category 3 - 111 to 129 mph

Category 4 - 130 to 156 mph

Category 5 - 157 or higher mph

Interesting Facts about Hurricanes

Hurricanes rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. This is due to the rotation of the Earth called the Coriolis effect.

The letters Q, U, X, Y, and Z are not used for the first letter when naming hurricanes.

The names are alternated between boy and girl names.

Weather forecasters draw a cone showing where they think the hurricane is most likely to travel.

You can always find out the latest information on hurricanes at the website of the National Hurricane Center which tracks and forecasts hurricanes.

Activities

Take a ten question quiz about this page.

Listen to a recorded reading of this page:

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Earth Science Subjects

Science >> Earth Science for Kids

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Kids learn about hurricanes (Tropical Cyclones) including how they form, names, eye, eye wall, rainbands, locations, seasons, facts, and categories.

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NASA Space Place

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How Do Hurricanes Form? | NASA Space Place – NASA Science for Kids

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National Geographic for Kids

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Hold on tight, gang - and we mean super tight! - because we're about to check out ten facts on one of nature's most powerful forces - hurricanes!

1. Hurricanes are giant tropical storms that produce heavy rainfall and super-strong winds.

2. Hurricanes form over warm ocean waters near the equator. The warm, moist air above the ocean surface rises, causing air from surrounding areas to be "sucked" in. This "new" air then becomes warm and moist, and rises, too, beginning a continuous cycle that forms clouds. The clouds then rotate with the spin of the Earth. If there is enough warm water to feed the storm, a hurricane forms!

3. Hurricanes rotate around a circular centre called the " eye ", where it is generally calm with no clouds. Surrounding the eye is the eye wall - the most dangerous part of the hurricane with the strongest winds, thickest clouds and heaviest rain!

4. Most hurricanes occur harmlessly out at sea. However, when they move towards land they can be incredibly dangerous and cause serious damage.

5. The strong spiraling winds of a hurricane can reach speeds of up to 320kmph - strong enough to rip up entire trees and destroy buildings!

6. In the southern hemisphere, hurricanes rotate in a clockwise direction, and in the northern hemisphere they rotate in an anti-clockwise direction. This is due to what's called the Coriolis Force, produced by the Earth's rotation.

7. When a hurricane reaches land it often produces a " storm surge". This is when the high winds drive the sea toward the shore, causing water levels to rise and creating large crashing waves. Storm surges can reach 6m high and extend to over 150km!

8. Hurricanes are also called cyclones and typhoons, depending on where they occur. In the Atlantic Ocean and Northwest Pacific they are hurricanes, in the Northwest Pacific they are typhoons and in the South Pacific and Indian Ocean they are cyclones.

9. The largest hurricane on record is Typhoon Tip, which occurred in 1979 in the northwest Pacific. With a diameter of around 2,220km, it was nearly half the size of the United States!

10. Hurricanes are given names by the World Meteorological Organisation (WMO) so that they can be distinguished. Each year, tropical storms are named in alphabetical order according to a list produced by the WMO. That name stays with the storm if it develops into a hurricane. The names can only be repeated after six years.

Photos: Getty Images UK

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10 Facts about Hurricanes! - National Geographic Kids

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Check out ten top facts about hurricanes here at National Geographic Kids! Learn how hurricanes form, what the world's biggest hurricane is and more!

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Weather Wizz Kids Website

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Hurricanes only form over really warm ocean water of 80°F or warmer. The atmosphere (the air) must cool off very quickly the higher you go. Also, the wind must be blowing in the same direction and at the same speed to force air upward from the ocean surface. Winds flow outward above the storm allowing the air below to rise. Hurricanes typically form between 5 to 15 degrees latitude north and south of the equator. The To learn more about hurricanes, Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water. Have a NOAA weather radio handy with plenty of batteries, so you can listen to storm advisories. Have some cash handy as well, because following a hurricane, banks and ATMs may be temporarily closed. Make sure your car is filled with gasoline. Hurricanes

What is a hurricane?
A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Each hurricane usually lasts for over a week, moving 10-20 miles per hour over the open ocean. Hurricanes gather heat and energy through contact with warm ocean waters. Evaporation from the seawater increases their power. Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere. The center of the storm or "eye" is the calmest part. It has only light winds and fair weather. When they come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.

>Click Here to get your very own Hurricane Tracking Chart.

How do hurricanes form?
Coriolis Force is needed to create the spin in the hurricane and it becomes too weak near the equator, so hurricanes can never form there.

What is storm surge?
Storm surges are frequently the most devastating element of a hurricane. As a hurricane's winds spiral around and around the storm, they push water into a mound at the storm's center. This mound of water becomes dangerous when the storm reaches land because it causes flooding along the coast. The water piles up, unable to escape anywhere but on land as the storm carries it landward. A hurricane will cause more storm surge in areas where the ocean floor slopes gradually. This causes major flooding.
As you watch the storm-surge animations, notice the effect that the physical geography of each coastline has on storm surge. Also, note the waves on top of the ocean's surface. Wind, waves, and sea-level rise all contribute to storm-surge damage.

Shallow-Water Coastline

Deep-Water Coastline

With technology the way it is, there are computer models that allow forecasters to predict the amount of storm surge that will affect a coastal area. These are called Slosh Models and take into account a storm's strength, its path, how the ocean shallows, and the shape of the land. Then it calculates how much storm surge a hurricane will probably cause.

The Atlantic hurricane season is from June 1 to November 30, but most hurricanes occur during the fall months. The Eastern Pacific hurricane season is from May 15 to November 30. (Below is a graphic that shows you when hurricanes are most active across parts of the world.)
When does hurricane season start?

Who names hurricanes?
From 1950 to 1952, tropical cyclones of the North Atlantic Ocean were identified by the phonetic alphabet (Able-Baker-Charlie-etc.), but in 1953 the US Weather Bureau switched to women's names. The rest of the world eventually caught on, and naming rights now go by the World Meteorological Organization, which uses different sets of names depending on the part of the world the storm is in. Around the U.S., only women's names were used until 1979, when it was decided that they should alternate a list that included men's names too. There's 6 different name lists that alternate each year. If a hurricane does significant damage, its name is retired and replaced with another.
Atlantic Hurricane Names
Eastern Pacific Hurricane Names
Nothing except geography. Tropical storms occur in several of the world's oceans, and except for their names, they are essentially the same type of storm. In the Atlantic Ocean, Gulf of Mexico, and the Eastern Pacific Ocean, they are called hurricanes. In the Western Pacific Ocean, they are called typhoons. In the Indian Ocean, the Bay of Bengal, and Australia, these types of storms are called cyclones.
What is the difference between a hurricane and a typhoon?
(This is a satellite animation of Hurricane Georges, which struck the Mississippi Gulf coast in 1998.)

The brave "hurricane hunters" work for the National Oceanic and Atmospheric Administration (NOAA). Each mission lasts about ten hours, with the crews passing four to six times through the storm. The planes carry radar, sophisticated computers, and weather instruments that determine characteristics such as temperature, air pressure, wind speed, and wind direction inside the hurricane. The crews also release instruments that measure temperature, air pressure, and wind at different levels as the devices drop through the hurricane toward the ocean. By mission's end, NOAA can warn everyone in the hurricane's path. (Below is a satellite image of Hurricane Mitch back in October 1998. The Hurricane Hunters flew into the eye of Mitch just as this Category 5 hurricane with winds of 155 mph smacked right into Central America.)

Who are the "Hurricane Hunters"?
Coastal beach erosion is the wearing away of land, the removal of beach or dune sediments by wave action, tidal currents, wave currents, or drainage. Waves are generated by storms, wind, or hurricanes and can cause coastal erosion. This may take the form of long-term losses of sediment and rocks, or merely the temporary redistribution of coastal sediments.

What is coastal beach erosion?

Hurricanes...Past and Present
Tropical Tracks: Click to see the tracks of this year's storms.

Know the Lingo Past Hurricane Info: Click to find all the data and information about a specific hurricane by just knowing the year.
HURRICANE WATCH - Hurricane conditions with sustained winds of 74 mph or greater are possible in your area within the next 36 hours. This WATCH should trigger your family's disaster plan, and protective measures should be initiated. Especially, those actions that require extra time such as securing a boat and leaving a barrier island.
TROPICAL STORM WATCH - Tropical Storm conditions with sustained winds from 39 -74 mph are possible in your area within the next 36 hours.
HURRICANE WARNING - Hurricane conditions are expected in your area within 24 hours. Once this WARNING has been issued, your family should be in the process of completing protective actions and deciding the safest location to be during the storm.

COASTAL FLOOD WATCH - The possibility exists for the inundation of land areas along the coast within the next 12 to 36 hours.

COASTAL FLOOD WARNING - Land areas along the coast are expected to become, or have become, inundated by sea water above the typical tide action.

SMALL CRAFT ADVISORY - A small craft advisory is a type of warning issued by the National Weather Service, most frequently in coastal areas. It is issued when winds have reached, or are expected to reach within 12 hours, a speed marginally less than that which is considered gale force, usually 25-38 mph.

Click Here to see if there are any active warnings in your area.
Hurricane Stages
Saffir-Simpson Hurricane Scale

Category

Winds (MPH)

Pressure (Millibars)

Pressure (Inches)

Storm Surge
(Feet)

Damage

3

111-130

964-945

28.47-27.91

9'-12'

Extensive

Click Here to watch a variety of videos teaching you the ins and outs of nature's fury. I would like to give a special thanks to Pinellas County Emergency management for putting these instructional videos together.
Hurricane Safety Tips

BEFORE A HURRICANE: Have a disaster plan and a pet plan ready. Before a storm threatens, contact your veterinarian or local humane society for information on preparing your pets for an emergency. Board up windows and b ring in outdoor objects that could blow away. Make sure you know which county or parish you live in and k now where all the evacuation routes are.

Stay away from low-lying and flood prone areas. Always stay indoors during a hurricane, because strong winds will blow things around. Leave mobile homes and to go to a shelter. DURING A HURRICANE: If your home isn't on higher ground, go to a shelter. If emergency managers say to evacuate, then do so immediately.
AFTER A HURRICANE: Stay indoors until it is safe to come out. Check for injured or trapped people, without putting yourself in danger. Watch out for flooding which can happen after a hurricane. Do not attempt to drive in flooding water. Stay away from standing water. It may be electrically charged from underground or downed power lines. Don't drink tap water until officials say its safe to do so.

Evacuation Tips: Here is a list of tips on what you should do, if you chose to evacuate as a hurricane approaches.
Hurricane Activities
Hurricane Supply Checklist: Here is a list of what what you will need if you chose to stay at your home during a hurricane.
Lesson Plan: Here is a great lesson plan on learning about hurricane safety. In this activity, Owlie teaches kids about hurricanes and quizzes them about what they learned. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.
Lesson Plan: Here is a great lesson plan on understanding hurricanes. Students will learn how wind speed increases the height and why higher waves occur in shallower water. This activity is for grades 6-8.

Lesson Plan: Here is a great interactive lesson plan on allowing kids to create their very own hurricane. It lets you try to create ideal hurricane conditions by changing the winds, latitude, moisture, and sea temperature. It even keeps score! This is a great activity for 5-8th graders.Lesson Plan: Here is a great lesson plan on elementary reading comprehension. This lesson contains a broader vocabulary, more hurricane facts, and more thought-provoking writing prompts. It works well for grades 3-5. Note: This is a PDF file, so you need to have Adobe Acrobat Reader. Lesson Plan: Here is a great interactive lesson plan that lets kids aim a hurricane. It lets you move the hurricane symbol, high pressure symbol and low pressure symbol to track your very own hurricane. Sometimes your hurricane will make landfall, other times it misses the U.S. all together. It lets kid understand how important the setup of weather impacts where hurricanes go.

Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!
Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.
Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer.

Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Kids Learning Videos

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Hurricanes - Learning about Hurricanes for kids and children

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Movie

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Earthquakes can leave behind incredible devastation, while also creating some of the planet's most magnificent formations. Learn about the geophysics behind earthquakes, how they are measured, and where the most powerful earthquake ever witnessed occurred.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Meteor Showers 101 | National Geographic

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Kool Kids facts

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The word "hurricane" comes from 'Huracan', the god of big winds and evil spirits once worshiped by the Maya people of Central America. Here we take a look at some cool hurricane facts.

First - what is a hurricane? A hurricane is an intense tropical storm with powerful winds and heavy rain and can also create tornadoes, high waves and lots of flooding.

Where do hurricanes form?

They usually form in tropical parts of the world like the southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern Pacific Ocean. The Atlantic hurricane season lasts from June to November, with the peak season being from August to late October.

So, no visiting at those times then. Make sure your parents plan their holiday properly! The Eastern Pacific hurricane season begins on May 15 and ends November 30. Evaporation (when liquid changes to gas) from the seawater also increases their power.

The heat dissipates (reduces) as the hurricane moves toward the poles, sometimes causing extreme damage for people living along the coastlines where hurricanes take place.

Some Info about Hurricanes

Hurricanes range from about 100 miles (160 kilometers) to 1000 miles (1600 kilometers) wide. They can last from days to weeks and almost always form over the ocean.

They can have speeds over 200 miles per hour (322 kilometers per hour), with things flying all over and be can also have heavy rains with them, which can cause land/mud slides.

What needs to happen for a hurricane to form?

The ocean waters must be warm enough at the surface - about 80° Fahrenheit (26⁰ Celsius) or warmer to put enough heat and moisture into the atmosphere.

Atmospheric moisture from sea water evaporation must cool off very quickly and combine the heat and energy to form the powerful engine needed to propel the hurricane.

A wind must be blowing in the same direction and at the same speed to force air upward from the ocean surface. Bands of thunderstorms form, allowing the air to warm even more and rise higher into the atmosphere.

Winds flow outward above the storm and the air below rises. If the winds at the higher levels are not that strong, the structure can remain intact and grow stronger and this is the beginning of a hurricane.

When hurricanes come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.

The eye of the hurricane

The eye of a hurricane is the calmest spot. It is generally 20 (32 kilometers) to 30 miles (48 kilometers) wide. Amazingly the hurricane can be about 400 miles (644 kilometers) wide. The most violent activity takes place in the area immediately around the eye, called the "eyewall".

At the top of the eyewall, which is up to 50,000 feet (15,240 meters), most of the air is driven outward, which increases the upward motion of the air. Some of the air, however, moves inward and sinks into the eye. This actually creates a cloud-free area.

Hurricane winds in the northern hemisphere circulate in a counter-clockwise motion around the hurricane's centre or "eye," while hurricane winds in the southern hemisphere circulate clockwise. Wow, that's amazing!

Storm surges are usually the most devastating part of a hurricane. As a hurricane's winds spiral around and around the storm, they push water into a mound at the storm's centre. This mound of water becomes dangerous when the storm reaches land because it causes flooding along the coast.

The water piles up, unable to escape anywhere but on to land as the storm carries it forwards. A hurricane will cause more storm surge in areas where the ocean floor slopes gradually and this will cause major flooding.

The amount of surge that a hurricane can cause is measured on machines called Slosh Models. What a weird name.

From 1953 the United States Weather Bureau started naming hurricanes using women's names for North Atlantic hurricanes. The rest of the world eventually caught on, and now the World Meteorological Organization, is responsible for naming hurricanes.

It uses different types of names dependent on the part of the world the storm is in. Around the US only women's names were used. Then in 1979 they decided men's names should be used as well. If a hurricane creates huge damage, its name is retired and replaced with another.

Here are a few of the names from the 2015 list: Ana, Bill, Claudette, Danny, Erica, Fred. There are many more!

There are brave "hurricane hunters" who work for the National Oceanic and Atmospheric Administration (NOAA). Each mission lasts about ten hours, with the crews passing four to six times through the storm. Can you imagine? That just sounds crazy!

The planes carry radar, sophisticated computers and weather instruments that measure temperature, air pressure, wind speed, and wind direction inside the hurricane. The crews also release instruments that measure temperature, air pressure, and wind at different levels as the devices drop through the hurricane toward the ocean.

By mission's end, NOAA can warn everyone in the hurricane's path. At least it's a massive help to people.

Hurricanes can be tracked by weather satellites and weather radar closer to land.

What was one of the worst hurricanes in history?

One of the worst hurricanes in history was the Galveston hurricane in the 1900s, which devastated the city and killed between 6,000 and 12,000 people - mostly from drowning. That's frightening.

The 1970 Bhola Cyclone that struck Bangladesh killed over 300,000 people. Cyclones, hurricanes and typhoons are just different names for the same thing.
Earth Science

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Hurricane Facts For Kids The word "hurricane" comes from 'Huracan', the god of big winds and evil spirits once worshiped by the Maya people of Central America. Here we take a look at some cool hurricane facts. First - what is a hurricane?

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Weather for Kids

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What is a hurricane?

A hurricane is the most violent storm known on Earth.

Hurricanes are tropical storms. They take place between the Equator and the Tropic of Cancer to the north, or between the Equator and the Tropic of Capricorn to the south.

Hurricanes form at sea and cause dangerous, stormy seas.

Some hurricanes reach the land and can destroy buildings and trees.

A hurricane can blow high waves onto the land and cause flooding.

The Atlantic hurricane season lasts from the beginning of June until the end of November.

There are usually between four and six hurricanes in a year that will cause some destruction on land.

The winds in a hurricane do not blow from west to east or north to south. They blow round in a circle.

A hurricane is like a spinning top.

The winds in a hurricane blow in a circle.

North of the equator the winds in a hurricane blow in an anticlockwise direction.

South of the equator the winds blow in a clockwise direction.

The winds in a hurricane blow at a speed of at least 74 miles an hour. Their speed is often much more than this.

Hurricanes can be seen from space. This photograph from space shows Hurricane Ivan hitting the coast of America.

Hurricanes form a thick mass of swirling cloud which can be seen from space.

A hurricane can be six miles high and 400 miles wide.

An area of calmer weather lies in the centre of the hurricane. This is known as the 'eye of the storm'.

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Hurricane Facts - Hurricanes for Kids - What is a Hurricane - Weather Facts for kids

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A hurricane is the most violent storm known on Earth. Hurricanes are tropical storms. They take place between the Equator and the Tropic of Cancer to the north, or between the Equator and the Tropic of Capricorn to the south. Hurricanes form at sea and cause dangerous, stormy seas.

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Kis Discover Website

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What Is a Hurricane? | Kids Discover Online

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Nor'easters can occur in the eastern United States any time between October and April, when moisture and cold air are plentiful. A Nor'easter is named for the winds that blow in from the northeast and drive the storm up the east coast along the Gulf Stream, a band of warm water that lies off the Atlantic coast. They are known for dumping heavy amounts of rain and snow, producing hurricane-force winds, and creating high surfs that cause severe beach erosion and coastal flooding. Winter Storms

How do winter storms form?
Winter storms derive their energy from the clash of two air masses of different temperatures and moisture levels. Winter storms usually form when an air mass of cold, dry, Canadian air moves south and interacts with a warm, moist air mass moving north from the Gulf of Mexico. The point where these two air masses meet is called a front. If cold air advances and pushes away the warm air, it forms a cold front. When warm air advances, it rides up over the denser, cold air mass to form a warm front. If neither air mass advances, it forms a stationary front.

What are snowflakes?
Snowflakes are made of ice crystals. Each snowflake is six-sided and made of as many as 200 ice crystals. Snowflakes form in clouds where the temperature is below freezing. The ice crystals form around tiny bits of dirt that has been carried up into the atmosphere by the wind. As the snow crystals grow, they become heavier and fall toward the ground. Why is snow white?
Bright snow blinds us with its gleaming white color because it reflects beams of white light. Instead of absorbing light, snow's complex structure prevents the light from shining through its lattice formation. A beam of white sunlight entering a snow bank is so quickly scattered by a zillion ice crystals and air pockets that most of the light comes bouncing right back out of the snow bank. What little sunlight is absorbed by snow is absorbed equally over the wavelengths of visible light thus giving snow its white appearance. So while many natural objects get their blue, red, and yellow colors from absorbing light, snow is stuck with its white color because it reflects light.

What is thundersnow? How is snow formed?
Snow is commonly formed when water vapor undergoes deposition, which is when water vapor changes directly to ice without first becoming a liquid, high in the atmosphere at a temperature of less than 32°F and then falls to the ground. What is sleet?
Sleet is just rain drops that freeze into ice pellets before reaching the ground. Sleet usually bounces when hitting a surface and does not stick to objects. However, it can accumulate like snow and cause a hazard to motorists.
What is an ice storm?
An ice storm is a type of winter storm caused by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least 0.25-inch of ice on exposed surfaces.
What is freezing rain?
Freezing rain is just rain that falls onto a surface with a temperature below freezing. This causes it to freeze to surfaces, such as trees, cars, and roads, forming a coating or glaze of ice. Even small accumulations of ice can cause a significant hazard. How do ice storms form?
Ice storms form when a layer of warm air is between two layers of cold air. Frozen precipitation melts while falling into the warm air layer, and then proceeds to refreeze in the cold layer above the ground. This creates freezing rain or a glaze of ice.

What is frost? What is a frost quake?
Frost is white ice crystals that form on a surface, like the ground or leaves of a plant. Frost is created when the air temperature drops below freezing and the water vapor in the air freezes into ice crystals.

How is lake-effect snow formed?
As the cold air flows over the warm lake water, the relatively warm water heats the air's bottom layer as lake moisture evaporates into the cold air. Since warm air is lighter or less dense than cold air, the heated air rises and begins to cool. As the air cools, the moisture that evaporated into it condenses and forms clouds and snow begins falling from the cloud if the air is humid enough. (Graphic Credit: USA TODAY.) What is a Nor'easter?

What is Wind Chill? What is an Alberta Clipper? Click Here to calculate the Wind Chill.
An Alberta clipper is an area of low pressure that generally forms over Alberta, Canada, east of the Rocky Mountains. They develop east of the Rockies because air flowing eastward over the mountains creates favorable conditions. Once an Alberta Clipper forms it usually moves very rapidly to the southeast across the USA's northern Plains and then to the east off the mid-Atlantic Coast. Clippers usually cause only light precipitation with very few producing major snowstorms. However, if conditions are favorable, some Alberta clippers can rapidly intensify off the East Coast once the storm taps the relatively warm moist air over the Atlantic Ocean. The storms that rapidly intensify sometimes spread heavy snow over New England and southeastern Canada. Generally, the main weather features associated with Alberta clippers are some light snow and a reinforcement of cold air over the USA.
What is frostbite? How do blizzards form?

A blizzard is a long-lasting snowstorm with very strong winds and intense snowfall. You need three things to have a blizzard; cold air at the surface, lots of moisture, and lift. Warm air must rise over cold air.
What is an avalanche?
An avalanche is a moving mass of snow that may contain ice, soil, rocks, and uprooted trees. The height of a mountain, the steepness of its slope, and the type of snow lying on it all help determine the likelihood of an avalanche. Avalanches begin when an unstable mass of snow breaks away from a mountainside and moves downhill. The growing river of snow picks up speed as it rushes down the mountain. Avalanches have been known to reach speeds of 245 miles an hour (394 kilometers per hour)—about four times as fast as the speediest downhill skier.
Click Here to learn more about Avalanche Saftey.
Know the Lingo
WINTER WEATHER ADVISORIES - Issued for accumulations of snow, freezing rain, freezing drizzle, and sleet which will cause significant inconveniences and, if caution is not exercised, could lead to life-threatening situations.

Thundersnow is when thunder and lighting occur during a snowstorm. This occurs most often in late winter or early spring. To get thundersnow, you need a mass of cold air on top of warm air, plus moist air closer to the ground. Thundersnow starts out like a summer thunderstorm. The sun heats the ground and pushes masses of warm, moist air upward, creating unstable air columns. As it rises, the moisture condenses to form clouds, which are jostled by internal turbulence. The "tricky part" for making thundersnow is creating that atmospheric instability in the wintertime. For thundersnow to occur, the air layer closer to the ground has to be warmer than the layers above, but still cold enough to create snow. During thundersnow events, heavy snowfall is to be expected. In some cases, two inches per hour is possible.

Click Here to see if there are any active warnings in your area.

Winter Storm Safety Tips
BEFORE A WINTER STORM: Have a disaster plan and prepare a disaster supplies kit for your home and car. Include a first aid kit, emergency food supply, bottled water, battery-operated radio, flashlight, protective clothing, and blankets. Don't forget, be aware of changing weather. DURING A WINTER STORM: Stay indoors and dress warmly. Eat regularly, because food provides the body with energy for producing its own heat. Also, drink lots of water. If you must go outside, wear layered clothing, mittens and a hat. Watch for signs of hypothermia and frostbite. Remember to keep dry. Always change wet clothing to prevent the loss of body heat. If you must drive, carry a cell phone. Always, keep the gas tank full. Don't forget, let someone know where you're going, just in case your car gets stuck. If you're car gets stuck, stay with it and wait for help unless help is visible within 100 yards. Use maps and car mats to stay warm.

AFTER A WINTER STORM: Avoid driving until conditions have improved. Avoid overexertion! Heart attacks from shoveling snow are the leading cause of deaths during the winter. Also, check on neighbors to make sure they're okay.

Frost quakes are non-tectonic seismic events, meaning they are not caused by the shifting of the Earth's tectonic plates. Also known as cryoseisms, frost quakes are caused by a sudden rapid freezing of ground and bedrock, usually when temperatures go from above freezing to below zero. As moisture absorbed in the rock and soil freezes, it expands. This puts a great amount of stress on the areas around it. Eventually, the stress is too much and the soil and rock will crack in an "explosive" manner, creating a loud sound and even shaking the ground surface. Since temperatures are coldest in the overnight hours, most people experience frost quakes in the middle of the night. Winter Storm Activities
Lesson Plan: Here is a great lesson plan on learning about winter weather. In this activity, kids investigate aspects of winter weather, such as temperature and wind. They familiarize themselves with weather-related words. It's a great activity for K-2nd graders.

Cold air moves over warm water and is warmed from below. Moisture evaporates in the air.

Warm moist air rises downwind of lakes and forms heavy snow.

Lesson Plan: Here is a great lesson plan on learning about winter weather. In this activity, kids learn how winter storms form and about the different types of fronts. It's a great activity for 3rd-5th graders. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.
Measuring Snow Experiment: Here is a great experiment that lets kids measure snow. They let the snow melt and then measure it again. It teaches kids that snow is very dense and is why it holds more space than water.

The wind chill is the temperature your body feels when the air temperature is combined with the wind speed. The higher the wind speed the faster exposed areas of your body lose heat and the colder you feel.Melting Snow Experiment: Here is another experiment that teaches kids the difference between the freezing and melting process. It allows kids to take the temperature of a glass of snow. Then, watch the snow melt and observe how the temperature changed.

Frost Experiment: Here is a great experiment that lets kids make frost. They can see how dew turns into frost in a matter of minutes.Examining Snowflakes Experiment: Here is a great experiment that lets kids see snowflakes up close. They can examine the snowflake's six sides.
Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!
Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.
Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer.

Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

Frostbite is damage to the skin due to prolonged exposure to cold temperatures, usually below 32° F.

WINTER STORM WATCH - Alerts the public to the possibility of a blizzard, heavy snow, heavy freezing rain, or heavy sleet. Winter Storm Watches are usually issued 12 to 48 hours before the beginning of a winter storm.

WINTER STORM WARNING - Issued when hazardous winter weather in the form of heavy snow, heavy freezing rain, or heavy sleet is occurring. Winter Storm Warnings are usually issued 12 to 24 hours before the event is expected.

BLIZZARD WARNING - Issued for sustained or gusty winds of 35 mph or more, and falling or blowing snow creating visibilities at or below 1/4 mile. These conditions should persist for 3 hours.

FROST/FREEZE WARNING - Issued when below freezing temperatures are expected.

LAKE EFFECT SNOW ADVISORY - Issued when accumulation of lake effect snow will cause significant inconvenience.

LAKE EFFECT SNOW WARNING - Issued when heavy lake effect snow is occurring.

WIND CHILL ADVISORY - Issued when the wind chill temperature is forecast to be between -15°F to -24°F.

WIND CHILL WARNING - Issued when the wind chill temperature is forecast to be -25°F or lower.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Winter storms or snowstorms happen when warm, wet air meets with cold air. The warm, wet air mass and the cold air mass can each be 1000 km or more in diameter. Snowstorms affecting Northeastern United States often get their moisture from air moving north from the Gulf of Mexico and cold air from air masses coming down from the Arctic. In the Northwest United States warm, wet air from the Pacific Ocean cools when it is pushed upward by the mountains. Many different things can affect the direction of movement, moisture content and temperature of air masses. All of these differences affect the type and severity of the snowstorm.

Winter storms and blizzards can make several feet of snow that blow into big drifts. Sometimes the drifts can be over ten feet tall. They could even cover a house.

Lots of popular winter storms are part of North America's history. In 1846 the Donner Party traveled away by covered wagons from Illinois headed for Sutter's Fort near Sacramento, California. As an answer of bad decisions and slow going, they tried to go across the big Sierra Nevada Mountains in the late October. Usually, California is still warm at that time of the year. As the party crossed the Sierra Nevada Mountains, they did not see any snow and was not worried. However, after they left, a huge snowstorm hit. The party was forced to camp near Truckee, California. The snow was so deep that the wagon wheels became stuck, so they could not move anyplace. They tried to wait the storm out, but when one blizzard ended, another began immediately before they had time to escape. Their food became short, so some of the people decided to hike out and find help rather than to starve to death. Most of them died in the freezing weather, and many of those who stayed behind in the camp survived. Of the 87 people who started in Illinois, only 47 lived.

Images for kids

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Winter storms or snowstorms happen when warm, wet air meets with cold air. The warm, wet air mass and the cold air mass can each be 1000 km or more in diameter. Snowstorms affecting Northeastern United States often get their moisture from air moving north from the Gulf of Mexico and cold air from air masses coming down from the Arctic.

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Facts for Kids website

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Facts Just for Parents, Teachers and Students

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3. A ground blizzard occurs after snow has fallen and strong winds blow around loose snow on the ground, creating whiteouts and snowdrifts.

4. Some intensive blizzards can have wind speeds as strong as a category one or category two hurricane.

5. The northwest side of an intense winter storm system is often where blizzard conditions occur.

6. Any geographical location that has snowfall can have a blizzard or blizzard like conditions.

7. Blizzards are most often experienced in the Great Plains and upper Midwest of the United States.

8. The term Blizzard was coined by an Iowa newspaper in the 1870s to describe a snowstorm. The term became widespread and synonymous in the 1880s with dangerous snow storms across the United States and England.

9. A blizzard watch is issued when blizzard conditions are possible within 12 to 48 hours.

10. A blizzard warning is issued when blizzard conditions are occurring or expected to occur within 12 to 18 hours.

11. Traveling by car during a blizzard is extremely dangerous. Due to low visibility and dangerous road conditions accidents are far more likely to occur. A bomb cyclone blizzard in 2019 caused a one hundred car pileup in Colorado on I-25.

12. Traveling on foot during a blizzard can result in severe injury or even death. Hypothermia onsets rapidly during a blizzard and with low visibility it's easy to get lost. There are several verified cases of people dying in a blizzard just a few yards from their house.

13. Snowmageddon was a major blizzard that affected the majority of the Northeastern United States between February 5th and 6th in 2010. This massive winter storm brought historic snowfalls to every single Mid-Atlantic State. After the storm hit Washington, D.C. people were skiing in the streets.

14. The deadliest blizzard in the United States was the 1888 Great Blizzard. In two days, up to 4 feet of snow fell in affected areas (Connecticut, Massachusetts, New Jersey and New York), causing more than 400 fatalities.

15. The deadliest blizzard in the world was the 1972 Iran Blizzard. It's estimated that as much as 26 feet of snow fell during this historic blizzard, causing around 4,000 fatalities.

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Blizzard Facts For Kids - Facts Just For Kids

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3. A ground blizzard occurs after snow has fallen and strong winds blow around loose snow on the ground, creating whiteouts and snowdrifts. 4. Some intensive blizzards can have wind speeds as strong as a category one or category two hurricane. 5. The northwest side of an intense winter storm system is often where blizzard conditions occur.

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NASA Solar System Website

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What's that flash of light streaking across the sky? We call the objects that creates this brilliant effect by different names, depending on where it is.

Meteoroids are what we call "space rocks" that range in size from dust grains to small asteroids. This term only applies when they're in space.

NASA astronomer Peter Jenniskens with a asteroid meteorite found in the Nubian Desert of northern Sudan. Credit: NASA/SETI/P. Jenniskens

Most are pieces of other, larger bodies that have been broken or blasted off. Some come from comets, others from asteroids, and some even come from the Moon and other planets. Some meteoroids are rocky, while others are metallic, or combinations of rock and metal.

When meteoroids enter Earth's atmosphere, or that of another planet, like Mars, at high speed and burn up, they're called meteors. This is also when we refer to them as "shooting stars." Sometimes meteors can even appear brighter than Venus -- that's when we call them "fireballs." Scientists estimate that about 48.5 tons (44,000 kilograms) of meteoritic material falls on Earth each day.

When a meteoroid survives its trip through the atmosphere and hits the ground, it's called a meteorite.

Meteor Showers

Meteor Showers

Several meteors per hour can usually be seen on any given night. When there are lots more meteors, you're watching a meteor shower. Some meteor showers occur annually or at regular intervals as the Earth passes through the trail of dusty debris left by a comet (and, in a few cases, asteroids).

Meteor showers are usually named after a star or constellation that is close to where the meteors appear to originate in the sky. Perhaps the most famous are the Perseids, which peak around August 12 every year. Every Perseid meteor is a tiny piece of the comet Swift-Tuttle, which swings by the Sun every 135 years. Other notable meteor showers include the Leonids, associated with comet Tempel-Tuttle; the Aquarids and Orionids, linked to comet Halley, and the Taurids, associated with comet Encke. Most of this comet debris is between the size of a grain of sand and a pea and burns up in the atmosphere before reaching the ground. Sometimes, meteor dust is captured by high-altitude aircraft and analyzed in NASA laboratories.

When to Watch

When to Watch

* For observers in the northern hemisphere.
** Estimated rate per hour in under perfect conditions, based on activity in recent years

Finding Meteorites

Finding Meteorites

Most space rocks smaller than a football field will break apart in Earth's atmosphere. Traveling at tens of thousands of miles per hour, the object disintegrates as pressure exceeds the strength of the object, resulting a bright flare. Typically less than 5 percent of the original object will ever make it down to the ground. These meteorites, pieces of meteors that are found, typically range between the size of a pebble and a fist.

Don't expect to find meteorites after a meteor shower. Most meteor showers come from comets, whose material is quite fragile. Small comet fragments generally won't survive entry into our atmosphere. In theory, the Taurids and Geminids could send meteorites down to our surface every once in a while, but no remnants have been traced to them definitively.

A student from the University of Khartoum, Sudan searches the desert terrain for meteorites. Credit: NASA Ames Research Center / SETI / Peter Jenniskens

It can be difficult to distinguish a meteorite from an Earth rock by appearance alone in most parts of the world, but there are some special places where they're much easier to identify: deserts. In sandy deserts with large, open regions of sand and few rocks, dark meteorites stand out clearly. Similarly, meteorites can be much easier to spot in cold, icy deserts, such as the frozen plains of Antarctica.

Why Do We Care About Meteorites?

Why Do We Care About Meteorites?

Meteorites that fall to Earth represent some of the original, diverse materials that formed planets billions of years ago. By studying meteorites we can learn about early conditions and processes in the solar system's history. These include the age and composition of different planetary building blocks, the temperatures achieved at the surfaces and interiors of asteroids, and the degree to which materials were shocked by impacts in the past.

What Do Meteorites Look Like?

What Do Meteorites Look Like?

Meteorites may resemble Earth rocks, but they usually have a burned exterior that can appear shiny. This "fusion crust" forms as the meteorite's outer surface melts while passing through the atmosphere.

There are three major types of meteorites: the "irons," the "stonys," and the stony-irons. Although the majority of meteorites that fall to Earth are stony, most of the meteorites discovered long after they fall are irons. Irons are heavier and easier to distinguish from Earth rocks than stony meteorites.

How Do We Know Where Meteorites Come From?

How Do We Know Where Meteorites Come From?

Most meteorites found on Earth come from shattered asteroids, although some come from Mars or the Moon. In theory, small pieces of Mercury or Venus could have also reached Earth, but none have been conclusively identified.

Scientists can tell where meteorites originate based on several lines of evidence. They can use photographic observations of meteorite falls to calculate orbits and project their paths back to the asteroid belt. They can also compare compositional properties of meteorites to the different classes of asteroids. And they can study how old the meteorites are - up to 4.6 billion years.

This rock encountered by NASA's Curiosity Mars rover is an iron meteorite called "Lebanon." Lebanon is about 2 yards or 2 meters wide (left to right, from this angle). The smaller piece in the foreground is called "Lebanon B." Image Credit: NASA/JPL-Caltech/LANL/CNES/IRAP/LPGNantes/CNRS/IAS/MSSS

Martian rocks can be traced to the Red Planet because they contain pockets of trapped gas that matches what satellites and rovers have found at Mars. Similarly, if the composition of a meteorite resembles rocks that astronauts brought back from the Moon during the Apollo mission, it is likely to be lunar, too. We know that a class of meteorites called "howardite-eucrite-diogenite" (HED) came from the planet-like world Vesta in the asteroid belt, thanks to NASA's Dawn mission.

What Kinds of Meteorites Have Been Found?

More than 50,000 meteorites have been found on Earth.

Designated Northwest Africa (NWA) 7034, and nicknamed "Black Beauty," this Martian meteorite weighs approximately 11 ounces (320 grams). Credit: NASA

Of these, 99.8 percent come from asteroids. The remaining small fraction (0.2 percent) of meteorites is split roughly equally between meteorites from Mars and the Moon. The over 60 known Martian meteorites were blasted off Mars by meteoroid impacts. All are igneous rocks crystallized from magma. The rocks are very much like Earth rocks with some distinctive compositions that indicate Martian origin.

The nearly 80 lunar meteorites are similar in mineralogy and composition to Apollo mission Moon rocks, but distinct enough to show that they have come from other parts of the Moon. Studies of lunar and Martian meteorites complement studies of Apollo Moon rocks and the robotic exploration of Mars.

Meteorite Impacts in History

Meteorite Impacts in History

Early Earth experienced many large meteor impacts that caused extensive destruction. While most craters left by ancient impacts on Earth have been erased by erosion and other geologic processes, the Moon's craters are still largely intact and visible. Today, we know of about 190 impact craters on Earth.

A very large asteroid impact 65 million years ago is thought to have contributed to the extinction of about 75 percent of marine and land animals on Earth at the time, including the dinosaurs. It created the 180-mile-wide (300-kilometer-wide) Chicxulub Crater on the Yucatan Peninsula.

One of the most intact impact craters is the Barringer Meteor Crater in Arizona. It's about 0.6 miles (1 kilometer) across and was formed by the impact of a piece of iron-nickel metal approximately 164 feet (50 meters) in diameter. It is only 50,000 years old and so well preserved that it has been used to study impact processes. Since the 1890s geologists studied it, but its status as an impact crater wasn't confirmed until 1960.

Meteor Crater in Arizona. Note vehicles in parking lot for scale. Credit: USGS

Well-documented stories of meteorite-caused injury or death are rare. In the first known case of an extraterrestrial object to have injured a human being in the U.S., Ann Hodges of Sylacauga, Alabama, was severely bruised by a 8-pound (3.6-kilogram) stony meteorite that crashed through her roof in November 1954.

The only entry of a large meteoroid into Earth's atmosphere in modern history with firsthand accounts was the Tunguska event of 1908. This meteor struck a remote part of Siberia in Russia, but didn't quite make it to the ground. Instead, it exploded in the air a few miles up. The force of the explosion was powerful enough to knock over trees in a region hundreds of miles wide. Scientists think the meteor itself was about 120 feet (37 meters) across and weighed 220 million pounds (100 million kilograms). Locally, hundreds of reindeer were killed, but there was no direct evidence that any person perished in the blast.

More recently, in 2013 the world was startled by a brilliant fireball that streaked across the sky above Chelyabinsk, Russia. The house-sized meteoroid entered the atmosphere at over 11 miles (18 kilometers) per second and blew apart 14 miles (23 kilometers) above the ground. The explosion released the energy equivalent of around 440,000 tons of TNT and generated a shock wave that blew out windows over 200 square miles (518 square kilometers) and damaged buildings. More than 1,600 people were injured in the blast, mostly due to broken glass.

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In Depth | Meteors & Meteorites - NASA Solar System Exploration

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What's that flash of light streaking across the sky? We call the objects that creates this brilliant effect by different names, depending on where it is. Meteoroids are what we call "space rocks" that range in size from dust grains to small asteroids. This term only applies when they're in space.

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A meteor is a bright streak of light in the sky (a "shooting star" or a "falling star") produced by the entry of a small meteoroid into the Earth's atmosphere. If you have a dark clear sky you will probably see a few per hour on an average night; during one of the annual meteor showers you may see as many as 100/hour. Very bright meteors are known as fireballs; if you see one please report it.

Meteor History

Meteor showers can be very impressive. Samuel Taylor Coleridge's famous lines from The Rime of the Ancient Mariner:

The upper air burst into life!
And a hundred fire-flags sheen,
To and fro they were hurried about!
And to and fro, and in and out,
The wan stars danced between

And the coming wind did roar more loud,
And the sails did sigh like sedge;
And the rain poured down from one black cloud;
The Moon was at its edge

may have been inspired by the Leonid meteor shower that he witnessed in 1797.

Meteorites are bits of the solar system that have fallen to the Earth. Most come from asteroids, including few are believed to have come specifically from 4 Vesta; a few probably come from comets. A small number of meteorites have been shown to be of Lunar (23 finds) or Martian (22) origin.

One of the Martian meteorites, known as ALH84001 (left), is believed to show evidence of early life on Mars.

Though meteorites may appear to be just boring rocks, they are extremely important in that we can analyze them carefully in our labs. Aside from the few kilos of moon rocks brought back by the Apollo and Luna missions, meteorites are our only material evidence of the universe beyond the Earth.

Iron

primarily iron and nickel; similar to type M asteroids

Stony Iron

mixtures of iron and stony material like type S asteroids

Chondrite

by far the largest number of meteorites fall into this class; similar in composition to the mantles and crusts of the terrestrial planets

Carbonaceous Chondrite

very similar in composition to the Sun less volatiles; similar to type C asteroids

Achondrite

similar to terrestrial basalts; the meteorites believed to have originated on the Moon and Mars are achondrites

A "fall" means the meteorite was witnessed by someone as it fell from the sky. A "find" means the meteorite was not witnessed and the meteorite was found after the fact. About 33% of the meteorites are witnessed falls. The following table is from a book by Vagn F. Buchwald. Included are all known meteorites (4660 in all, weighing a total of 494625 kg) in the period 1740-1990 (excluding meteorites found in Antarctica).

A very large number of meteoroids enter the Earth's atmosphere each day amounting to more than a hundred tons of material. But they are almost all very small, just a few milligrams each. Only the largest ones ever reach the surface to become meteorites. The largest found meteorite (Hoba, in Namibia) weighs 60 tons.

The average meteoroid enters the atmosphere at between 10 and 70 km/sec. But all but the very largest are quickly decelerated to a few hundred km/hour by atmospheric friction and hit the Earth's surface with very little fanfare. However meteoroids larger than a few hundred tons are slowed very little; only these large (and fortunately rare) ones make craters.

A good example of what happens when a small asteroid hits the Earth is Barringer Crater (a.k.a. Meteor Crater) near Winslow, Arizona. It was formed about 50,000 years ago by an iron meteor about 30-50 meters in diameter. The crater is 1200 meters in diameter and 200 meters deep. About 120 impact craters have been identified on the Earth, so far (see below).

A more recent impact occurred in 1908 in a remote uninhabited region of western Siberia known as Tunguska. The impactor was about 60 meters in diameter and probably consisting of many loosely bound pieces. In contrast to the Barringer Crater event, the Tunguska object completely disintegrated before hitting the ground and so no crater was formed. Nevertheless, all the trees were flattened in an area 50 kilometers across. The sound of the explosion was heard half-way around the world in London.

There are probably at least 1000 asteroids larger than 1 km in diameter that cross the orbit of Earth. One of these hits the Earth about once in a million years or so on the average. Larger ones are less numerous and impacts are less frequent, but they do sometimes happen and with disastrous consequences.

The impact of a comet or asteroid about the size of Hephaistos or SL9 hitting the Earth was probably responsible for the extinction of the dinosaurs 65 million years ago. It left a 180 km crater now buried below the jungle near Chicxulub in the Yucatan Peninsula (right).

Calculations based on the observed number of asteroids suggest that we should expect about 3 craters 10 km or more across to be formed on the Earth every million years. This is in good agreement with the geologic record. It is more difficult to compute the frequency of larger impacts like Chicxulub but once per 100 million years seems like a reasonable guess.

Here are educated guesses about the consequences of impacts of various sizes:

Data from 'The Impact Hazard', by Morrison, Chapman and Slovic, published in Hazards due to Comets and Asteroids
More recent studies indicate a slightly lower frequency.

More about Meteorites

more images

Meteorites and their Properties, by David A. Kring (if you think you've found a meteorite read this)

New England Meteoritical Services (lots of info)

What is a Meteorite? by Paul Sipiera

near-Earth objects from RGO

Micrometeorites from LANL

Meteorite and Impacts Advisory Committee, includes info and more images

ANSMET, The Antarctic Search for Meteorites

Arizona meteorites, including a nice clickable map of finds in Arizona

International Meteor Organization

Meteor Streams, a concise table of meteor shower data

Gary Kronk's Meteor Showers page

the Dutch Meteor Society - info about current meteor showers (and more)

Leonid Meteor Outburst Home Page

SNC Meteorites

Lunar Meteorites

Mars Meteorites from Ron Baalke at JPL (lots of images!)

list of Martian Meteorites

Meteorite! magazine

Extrasolar material in meteorites

Americal Meteor Society including an informative two-part FAQ

NAU Meteorite LabMeteorites for sale

The Meteorite Market, info about meteorites and meteorite collecting and many nice images

The Meteorite Exchange, info and more links

R.A. Langheinrich Meteorites, includes a nice image gallery

Meteorites.com, also includes some classification info

Meteorite Express

Michael Blood Meteorites

meteorites.tv

Aerolite.org

Arizona Skies MeteoritesImpacts

Asteroid and Comet Impact Hazards from NASA AMES

Spaceguard survey

the Spacewatch Project

the Torino Scale of impact threat

The Impact Catastrophe (ExInEd hypercard stack)

Essay about the K-T Event by Calvin Hamilton of LANL

The Probability of Collisions with Earth (also from LANL)

text and pictures of Terrestrial Impact Craters (also from LANL)

a teacher's guide about Cosmic Collisions by Sally Stephens of PASP

The Barringer Meteorite Crater, nice site with lots of information

Tunguska Page from Southworth Planetarium

Tunguska Home Page

another Tunguska Home Page from the University of Bologna

meteorites sometimes hit houses!

Orbit Diagrams for various Near-Earth objects and comets

tables of past and future close approaches to the Earth and Potentially Dangerous NEOs

Asteroid 1999 AN10

nice atlas of Terrestrial Impact Structures (with maps and images)

another list of identified impact craters on Earth (plain text)

Catastrophism by Philip Burns

FIDAC (Fireball Data Center), including an online fireball report form

Meteor Research Resources Page

The Peekskill Fireball

simulation of a big comet impact by Sandia

Open Issues

Can we trace the origin of the various types of meteorites to a parent asteroid?

Was it a comet or an asteroid that caused the Chicxulub crater in the Yucatan (and probably caused the extinction of the dinosaurs)?

Will Spacewatch retain enough funding to finish its job of identifying all the potentially dangerous near-Earth asteroids?

Will we find more pieces of Mars in Antarctica?

Note

Here is what President of the United States Bill Clinton had to say about the discovery of evidence for life in a meteorite from Mars:

"It is well worth contemplating how we reached this moment of discovery. More than 4 billion years ago this piece of rock was formed as a part of the original crust of Mars. After billions of years it broke from the surface and began a 16 million year journey through space that would end here on Earth. It arrived in a meteor shower 13,000 years ago. And in 1984 an American scientist on an annual U.S. government mission to search for meteors on Antarctica picked it up and took it to be studied. Appropriately, it was the first rock to be picked up that year - rock number 84001.

Today, rock 84001 speaks to us across all those billions of years and millions of miles. It speaks of the possibility of life. If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined. Even as it promises answers to some of our oldest questions, it poses still others even more fundamental.

We will continue to listen closely to what it has to say as we continue the search for answers and for knowledge that is as old as humanity itself but essential to our people's future."

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Meteors, Meteorites and Impacts | Facts, Location, Size, Showers, History

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A meteor is a bright streak of light in the sky (a "shooting star" or a "falling star") produced by the entry of a small meteoroid into the Earth's atmosphere. If you have a dark clear sky you will probably see a few per hour on an average night; during one of the annual meteor showers you may see as many as 100/hour.

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Differences Between Meteor, Meteorite and Meteoroid

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Differences Between Meteor, Meteorite and Meteoroid

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NASA Website

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Shooting stars are actually bits of debris that fall through our atmosphere.

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What Happens When a Meteorite Hits Earth

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What Happens When a Meteorite Hits Earth

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Animation

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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Chances of an asteroid hitting are pretty small. NASA has tracked 90 percent of the near-Earth asteroids that are at least a half-mile (0.8 kilometers) wide and believes none of them has a significant chance of hitting Earth.

Still there could be some bigger asteroids out there that NASA doesn't know about. If a mile-wide asteroid hit Earth, it would strike the planet's surface at about 30,000 miles per hour (48,280 kilometers per hour). An asteroid that big traveling at that speed has the energy roughly equal to a 1 million-megaton bomb.

It's difficult to imagine 1 million megatons, so let's try some smaller sizes. Let's say that an asteroid the size of a house hit Earth at 30,000 miles per hour (48,280 kilometers per hour). It would have the energy roughly equal to the bomb that fell on Hiroshima - perhaps 20 kilotons. An asteroid like this would flatten reinforced concrete buildings up to half a mile from where it hit, and flatten wooden structures perhaps a mile and a half (0.8 kilometers) from ground zero. It would, in other words, do extensive damage to any city.

If the asteroid was as big as a 20-story building (200 feet [61 meters] on a side), it could have the amount of energy equal to the largest nuclear bombs made today - about 25 to 50 megatons. This size asteroid would flatten reinforced concrete buildings 5 miles (8 kilometers) from ground zero. It would completely destroy most major cities in the United States.

For an asteroid to wipe out most everything on Earth, it would have to be massive. Scientists estimate it would take an asteroid about 7 to 8 miles (11 to 12 kilometers) wide crashing into the Earth. Once it made impact, it would create a tremendous dust plume that would envelope the entire planet, block out the sun and raise temperatures where the asteroid made impact. Billions would die, and much of life on the planet would be destroyed. But, scientists believe some would survive. NASA scientists say it would take an asteroid 60 miles (96 kilometers) wide to totally wipe out life on Earth.

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There are obvious craters on Earth (and the moon) that are evidence of a long history of massive objects hitting planet Earth. But what would happen if an asteroid hit Earth today?

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What Happens When A Meteor Strikes Earth

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What Happens When A Meteor Strikes Earth

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Good Information Website

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Related on TestTube:
Huge Comet Just Barely Missed Mars
This Is What It Looks Like to Land on a Comet

Linguistically, a "meteoroid" is a small object from an asteroid or comet orbiting the sun. If it enters into the Earth's atmosphere and burns up, it's a shooting star or meteor. If there's anything left over after it hits the Earth's surface, that's a meteorite.

The surface of the Earth is constantly being bombarded anywhere between 1 to 300 metric tons of dust every day, satellite data suggests. Anything bigger than 2 millimeters can cause a streak of light in the sky. Better known as shooting stars, the flash of light we see is the result of the "star" burning up in our atmosphere. If a meteoroid is larger than the size of a marble ... that's when things can get scary. Just ask the dinosaurs.

Most of us have an idea of what happens to the surface of the Earth when it gets punched by a meteor, an asteroid, or a comet: craters form, giant dust clouds form, and things get apocalyptic in general. But a new study just released by scientists at Duke University simulated the effects of high-speed impacts on sand and soil in an effort to study what happens under the surface of such impacts, and what they found was quite interesting.

When an object hits the surface at high speeds, the soil or sand underneath the impact zone--unlike water--isn't displaced but actually solidifies. They experimented with projectile speeds up to 670 miles per hour (300 m/s) and noticed that the faster the impact, the more the surface absorbed the impact and spread the kinetic energy over a wider area of soil. So the craters left by big missiles or meteors aren't displaced ground, but actually the blast zone.

Huge Tunguska Explosion Remains Mysterious 100 Years Later (Space.com)
"A full century after the mysterious Tunguska explosion in Siberia leveled an area nearly the size of Tokyo, debate continues over what caused it."

Near Earth Objects & Impact Effects (Space Guard Centre)
"Near Earth Objects are asteroids or comets that have orbits around the Sun that bring them close to the Earth. The actual definition of an NEO is a comet or asteroid whose orbit brings it close to Earth's orbit. The criterion is a perihelion distance < 1.3 AU."

An analysis of the physical, chemical, optical, and historical impacts of the 1908 Tunguska meteor fall (Science Direct)
"A detailed analysis of the physical nature and photochemical after effects of the explosive cometary meteor Tunguska is presented."

Getting a Handle on How Much Cosmic Dust Hits Earth (Universe Today)
"Estimates vary of how much cosmic dust and meteorites enter Earth's atmosphere each day, but range anywhere from 5 to 300 metric tons, with estimates made from satellite data and extrapolations of meteorite falls."

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What Happens When A Meteor Strikes Earth?

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Related on TestTube: Huge Comet Just Barely Missed Mars This Is What It Looks Like to Land on a Comet Linguistically, a "meteoroid" is a small object from an asteroid or comet orbiting the sun. If it enters into the Earth's atmosphere and burns up, it's a shooting star or meteor.

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Time and again huge rocks pass by relatively close to Earth. In April 2018, for example, an asteroid named 2018GE3 with a diameter of 50 meters (164 feet) got dangerously close to us. It came from the dark depth of space and astronomers discovered it only 21 hours before the flyby.

Five years before that, a 20-meter meteorite hit the Earth close to Chelyabinsk in Russia. Catastrophy was avoided and consequences were relatively mild. Thousands of buildings were damaged by the blast's wave and more than a thousand people were injured, especially by flying glass fragments. But fortunately there were no deaths.

Astronomers are quite confident that they know where the even more lethal objects are, rocks that are several kilometres in diameter. They hope that planet Earth is not threatened by any such huge danger for at least the next 100 years.
Read more: Medium-sized projectiles are difficult to predict Japanese spacecraft Hayabusa2 lands on asteroid
But the "smaller" rocks with only several hundreds of meters in diameter can already cause devastating regional damage. The cases of the two asteroids mentioned above also show that we cannot possibly know them all.

For this reason, 300 astronomers, space engineers and other experts from the US, Russia, China, Germany, France and Israel are discussing the "space situation" this week.

At the 6th IAA Planetary Defense Conference in Maryland, USA, the main focus will be on possible defense strategies. The North American Space Agency NASA is organizing the conference together with researchers from the Johns Hopkins Applied Physics Laboratory (APL).
Read more: Asteroids and comets: How to tell them apart
The scientists have devised a hypothetical asteroid up to 300 meters in size, which races towards the Earth at a speed of 14 kilometers (8.6 miles) per second, i.e. around 50,000 kilometers per hour, from a distance of 57 million kilometers. The probability that it will hit us is estimated at one percent. One way to deal with this would be to evacuate the threatened regions on Earth.
Evacuate or deflect?

Astronaut Alexander Gerst took a picture of this meteorite crater in Arizona

At the conference, however, the participants will also demonstrate various methods by which mankind can deflect the asteroid from its dangerous path, such as NASA's Double Asteroid Redirection Test (DART)developed by NASA's Planetary Defense Coordination Office in Washington, together with APL. In 2022, a real 150-meter-diameter asteroid, which is not posing a current danger for Earth, is to be deflected from its orbit by a collision. The researchers want to find out whether such a method promises success.

Read more: Greenland: Massive 31-kilometer crater discovered beneath ice

DART is part of a National Near-Earth Object Preparedness Strategy and Action Plan. Asteroids whose orbit around the sun is closer than 50 million kilometers to the Earth's orbit are considered "near-Earth." More than 20,000 of them are known and 700 are added every year.
Not visible in the dark
"We have to make sure people understand this is not about Hollywood," said NASA administrator Jim Bridenstine at the opening of the conference, according to AFP.

His colleague Detlef Koschny from the European Space Agency ESA agreed with him: "The positive aspect of Chelyabinsk is that it made the public aware, it made the political decision makers aware."

The greatest uncertainty emanates from objects close to the sun, which are virtually invisible from the Earth due to the light conditions. These can only be discovered, if at all, with special telescopes that are located in Arizona, Hawaii, Chile, Spain and Sicily.

Now astronomers are also discussing the construction of a space telescope for this purpose. It could search from a different perspective. Alternatively, a telescope could be erected on the far side of the moon. It would have a much better view into the depth of the universe, with the moon shielding it from radiation and light coming from Earth.

Threat from above

And after all that...

... the chance of a large asteroid hitting Earth in the next 100 years is (said to be) quite small.

Author: F. Schmidt / J. Hartl / jbr

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Can we protect Earth from asteroids? | DW | 30.04.2019

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Time and again huge rocks pass by relatively close to Earth. In April 2018, for example, an asteroid named 2018GE3 with a diameter of 50 meters (164 feet) got dangerously close to us. It came from the dark depth of space and astronomers discovered it only 21 hours before the flyby.

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Australia is a land that has known fire. Our diverse plant and animal species have become accustomed to life with fire, and in fact some require it to procreate.

But in recent decades the pattern of fires - also known as the fire regime - is changing. Individual fires are increasingly hotter, more frequent, happening earlier in the season and covering larger areas with a uniform intensity. And these changes to the fire regime are occurring too fast for our native flora and fauna to adapt and survive.

Read more: Some say we've seen bushfires worse than this before. But they're ignoring a few key facts

Our fire-adapted plants are suffering

Many of Australia's iconic eucalypts are "shade intolerant" species that adapted to exist within a relatively harsh fire regime. These species thrive just after a major fire has cleared away the overstory and prepared an ash bed for their seeds to germinate.

Some of our most majestic trees, like the alpine ash, can only regenerate from seed. Those seeds germinate only on bare earth, where the leaf litter and shrubs have been burnt away.

But if fire is so frequent the trees haven't matured enough to produce seed, or so intense it destroys the seeds present in the canopy and the ground, then even these fire-adapted species can fail.

The current fires are re-burning some forests that were burnt only a decade ago. Those regenerating trees are too young to survive, but also too young to have started developing seed.

With the disappearance of these tree species, other plants will fill the gap. Acacias (wattles) are potential successors as they mature much earlier than alpine ash. Our tall, majestic forests could easily turn into shrubby bushland with more frequent fires.

from www.shutterstock.com

Even within a burnt area, there are usually some unburnt patches, which are highly valuable for many types of plants and animals. These patches include gullies and depressions, but sometimes are just lucky coincidences of the terrain and weather. The patches act as reserves of "seed trees" to provide regeneration opportunities.

Recent fires, burning in hotter and drier conditions, are tending to be severe over large areas with fewer unburnt patches. Without these patches, there are no trees in the fire zone to spread seeds for regeneration.

Eucalypt seed is small and without wings or other mechanisms to help the wind disperse it. Birds don't generally disperse these seeds either. Eucalypt seed thus only falls within 100 - 200 metres of the parent tree. It may take many decades for trees to recolonise a large burnt area.

That means wind-blown or bird-dispersed seeds from other species may fully colonise the burnt area well before the Eucalypts. Unfortunately many of these windblown seeds will be weed species, such as African Love Grass, which may then cover the bare earth and exclude successful Eucalypt regeneration while potentially making fires even hotter and more frequent.

Animals have fewer places to hide

Young animals are significantly more vulnerable to disturbances such as fire than mature individuals. So the best time to give birth is a season when fire is rare.

Spring in the southern zones of Australia has, in the past, been wetter and largely free from highly destructive fires. Both flora and fauna species thus time their reproduction for this period. But as fire seasons lengthen and begin earlier in the year, vulnerable nestlings and babies die where they shelter or starve as the fires burn the fruits and seeds they eat.

Australian fauna have developed behaviours that help them survive fire, including moving towards gullies and depressions, climbing higher, or occupying hollows and burrows (even if not their own) when they sense fire.

from www.shutterstock.com

But even these behaviours will fail if those refuges are uncharacteristically burning under hotter and drier conditions. Rainforest, marshes and the banks of watercourses were once safe refuges against fire, but we have seen these all burn in recent fires.

Read more: Animal response to a bushfire is astounding. These are the tricks they use to survive

What can be done?

All aspects of fire regimes in Australia are clearly changing as a result of our heating and drying climate. But humans can have a deliberate effect, and have done so in the past.

Indigenous burning created a patchwork of burnt areas and impacted on the magnitude and frequency of fires over the landscape. These regular burns kept the understory under control, while the moderate intensity and patchiness allowed larger trees to survive.

Read more: There's no evidence 'greenies' block bushfire hazard reduction but here's a controlled burn idea worth trying

There have been repeated calls of late to reintroduce Indigenous burning practices in Australia. But this would be difficult over vast areas. It requires knowledgeable individuals to regularly walk through each forest to understand the forest dynamics at a very fine scale.

More importantly, our landscapes are now filled with dry fuel, and shrubs that act as "ladders" - quickly sending any fire into tree canopies to cause very destructive crown fires. Given these high fuel conditions along with their potentially dangerous distribution, there may be relatively few safe areas to reintroduce Indigenous burning.

The changed fire conditions still require active management of forests, with trained professionals on the ground. Refuges could be developed throughout forests to provide places where animals can shelter and from which trees can recolonise. Such refuges could be reintroduced by reducing forest biomass (or fuel) using small fires where feasible or by mechanical means.

David Mariuz/AAP

Biomass collected by machines could be used to produce biochar or other useful products. Biochar could even be used to improve the soil damaged by the fires and excess ash.

Midstory species could be cut down to prevent the development of fire ladders to tree crowns. Even the overstory could be thinned to minimise the potential for crown fires. Seed could also be collected from thinned trees to provide an off-site bank as ecological insurance.

Such active management will not be cheap. But using machinery rather than fire could control biomass quantity and distribution in a much more precise way: leaving some biomass on the ground as habitat for insects and reptiles, and removing other patches to create safer refuges from the fires that will continue to come.

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Many of our plants and animals have adapted to fires, but now the fires are changing

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Australia is a land that has known fire. Our diverse plant and animal species have become accustomed to life with fire, and in fact some require it to procreate. But in recent decades the pattern of fires - also known as the fire regime - is changing.

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Have you ever wondered how our native wildlife manage to stay alive when an inferno is ripping through their homes, and afterwards when there is little to eat and nowhere to hide? The answer is adaptation and old-fashioned ingenuity.

Australia's bushfire season is far from over, and the cost to wildlife has been epic. A sobering estimate has put the number of animals killed across eastern Australia at 480 million - and that's a conservative figure.

But let's look at some uplifting facts: how animals survive, and what challenges they overcome in the days and weeks after a fire.

Sensing fire

In 2018, a staff member at Audubon Zoo in the United States accidentally burned pastry, and noticed something peculiar. In nearby enclosures ten sleepy lizards, or Tiliqua rugosa, began pacing and rapidly flicking their tongues. But sleepy lizards in rooms unaffected by smoke remained burrowed and calm.

It was obvious the lizards sensed the smoke from the burnt pastry, probably through olfaction, or sense of smell (which is enhanced by tongue flicking). So the lizards were responding as they would to a bushfire.

In Australia, experiments have shown smoke also awakens Gould's long-eared bats and fat-tailed dunnarts, enabling their escape from fire.

Read more: Bushfires have reshaped life on Earth before. They could do it again

Animals also recognise the distinct sounds of fire. Reed frogs flee towards cover and eastern-red bats wake from torpor when played the crackling sounds of fire.

Other species detect fire for different reasons. Fire beetles from the genus Melanophila depend on fire for reproduction, as their larvae develop in the wood of burned trees. They can detect fire chemicals at very low concentrations, as well as infrared radiation from fires.

The beetles can detect very distant fires; one study suggests individuals of some species identify a fire from 130km away.

Stay or go?

Once an animal becomes aware of an approaching fire, it's decision time: stay or go?

It's common to see large animals fleeing a fire, such as the kangaroos filmed hopping from a fire front in Monaro in New South Wales a few days ago. Kangaroos and wallabies make haste to dams and creek lines, sometimes even doubling back through a fire front to find safety in areas already burned.

Other animals prefer to stay put, seeking refuge in burrows or under rocks. Smaller animals will happily crash a wombat burrow if it means surviving a fire. Burrows buffer animals from the heat of fires, depending on their depth and nearby fuel loads.

From here, animals can repopulate the charred landscape as it recovers. For example, evidence suggests populations of the agile antechinus (a small carnivorous marsupial) and the bush rat recovered primarily from within the footprint of Victoria's Black Saturday fires.

Avoiding fire is only half the battle

The hours, days, and weeks after fire bring a new set of challenges. Food resources will often be scarce, and in the barren landscape some animals, such as lizards and smaller mammals, are more visible to hungry predators.

Birds of prey arrive quickly at fires. Several species in northern Australia have been observed intentionally spreading fires by transporting burning sticks in their talons or beaks.

Read more: Making sense of Australia's bushfire crisis means asking hard questions - and listening to the answers

One US study published in 2017 recorded a seven-fold increase in raptor activity during fire. They begin hunting as the fires burn, and hang around for weeks or months to capitalise on vulnerable prey.

In Australia, introduced predators can also be drawn to fires. Feral cats have been observed travelling up to 12.5km from their home ranges towards recently burned savanna ecosystems, potentially drawn by distant smoke plumes promising new prey.

A 2016 study found a native rodent was 21 times more likely to die in areas exposed to intense fire compared to unburned areas, mostly due to predation by feral cats. Red foxes have an affinity for burned areas too.

So should a little critter hunker down, or begin the hazardous search for a new home?

Staying put

Perhaps because of the risks of moving through an exposed landscape, several Australian mammals have learnt to minimise movement following fire. This might allow some mammal populations to recover from within a fire footprint.

Native mammals have been found hiding in beds of ash after fires.

Read more: Koalas are the face of Australian tourism. What now after the fires?

Short-beaked echidnas seek refuge and, when finding it, lower their body temperature and limit activity, so reducing the amount of food they need for energy. Despite their spiny defences, echidnas have been found more often in the stomachs of foxes following fire, so staying put in a little refuge is a good move.

Small marsupials such as brown and yellow-footed antechinus also use torpor to suppress their energy use and therefore the need to seek food.

Running the gauntlet

Not all wildlife have adapted to stay put after a fire, and moving in search of a safe haven might be the best option.

Animals might take short, information-gathering missions from their refuges into the fireground before embarking on a risky trek. They may, for example, spot a large, unburned tree that would make good habitat, and so move towards it. Without such cues to orient their movement, animals spend more time travelling, wasting precious energy reserves and increasing the risk of becoming predator food.

Survival is not assured

Australia's animals have a long, impressive history of co-existing with fire. However, a recent study I led with 27 colleagues considered how relatively recent threats make things much harder for animals in fire-prone landscapes.

Some native species are not accustomed to dealing with red foxes and feral cats, and so might overlook cues that indicate their presence, and make the bad decision to move through a burned landscape when they should stay put.

Read more: Listen to your people Scott Morrison: the bushfires demand a climate policy reboot

When fires burn habitat in agricultural or urban landscapes, animals might encounter not just predators but vehicles, livestock and harmful chemicals.

And as this bushfire season has made brutally clear, climate change is increasing the scale and intensity of bushfires. This reduces the number of small refuges such as fallen logs, increases the distance animals must cover to find new habitat and leaves fewer cues to direct them to safer places.

We still have a lot to learn about how Australia's wildlife detect and respond to fire. Filling in the knowledge gaps might lead to new ways of helping wildlife adapt to our rapidly changing world.

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Animal response to a bushfire is astounding. These are the tricks they use to survive

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Have you ever wondered how our native wildlife manage to stay alive when an inferno is ripping through their homes, and afterwards when there is little to eat and nowhere to hide? The answer is adaptation and old-fashioned ingenuity. Australia's bushfire season is far from over, and the cost to wildlife has been epic.

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What Happens to Lava After Erupting From a Volcano?

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What Happens to Lava After Erupting From a Volcano?

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What Happens to Lava After Erupting From a Volcano? 

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Positive and Negative Effects of Volcanoes

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Positive and Negative Effects of Volcanoes

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The positive and negative consequences of volcanoes - Volcanoes - OCR - GCSE Geography Revision - OCR - BBC Bitesize

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Learn about and revise different types of volcanoes and their characteristics and effects with GCSE Bitesize Geography (OCR).

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The Asteroid-impact Theory

The primary cause of the Cretaceous mass extinction was a mystery for decades, until geologists discovered a thin layer of rock that marks the boundary between the Cretaceous period and following Tertiary period; this layer of sediments is termed the K-T boundary, and gave rise to the asteroid-impact theory of the Cretaceous extinction.

The asteroid-impact theory was first proposed in detail in 1978, by a team led by American geologist Walter Alvarez (1940-) and physicist Luis Alvarez (1911-). The Alvarez team analyzed sediment collected in the 1970s from the K-T layer near the town of Gubbio, Italy. The samples showed a high concentration of the element iridium, a substance rare on but relatively abundant in meteorites. Other samples of K-T boundary from around the world were also analyzed; excess iridium was found in these samples as well. Using the average thickness of the sediment as a guide, they calculated that a meteorite about 6 mi (10 km) in diameter would be required to spread that much iridium over the whole Earth.

If a meteorite that size had hit Earth, the dust lofted into the air would have produced an enormous cloud of dust that would have encircled the world and blocked out the sunlight for months, possibly years. This climactic change would have severely depressed photosynthesis, resulting in the death of many plants, subsequent deaths of herbivores, and finally the death of their predators as well. (This chain of events would have occurred so rapidly that there would have been no chance for evolutionary adaptation to the new environment, which requires thousands of years at minimum.) A major problem with the theory, however, was that a 6-mi (10-km) meteorite would leave a very large crater, 93-124 mi (150-200 km) in diameter-and while Earth has many impact craters on its surface, few are even close to this size, and none of the right age was known.

Because 65 million years had passed since the hypothetical impact, scientists shifted the search underground. A crater that old would almost certainly have been filled in by now. In 1992, an impact crater was discovered under the surface near the village of Chicxulub (pronounced CHIX-uh-loob) on Mexico's Yucatan Peninsula. When core samples raised by drilling were analyzed, they showed the crater to be about 112 mi (80 km) in diameter and 65 million years old-the smoking gun that validated the Alvarez asteroid-impact theory.

The asteroid impact theory is now widely accepted as the most probable explanation of the K-T iridium anomaly, but many geologists still debate whether the impact of this large meteorite was the sole cause of the mass extinction of the dinosaurs and other life forms at that time, as the fossil record seems to show an above-average rate of extinctions in the time leading up to the K-T boundary. A number of gradual causes can accelerate extinction: falling ocean levels, for example, expose continental shelves, shrinking shallow marine environments and causing drier continental interiors, both changes that encourage extinction. Further, very large volcanic eruptions may stress the global environment. The asteroid that caused the Chicxulub crater may have coincidentally amplified or punctuated an independent extinction process that had already begun. There is no reason why many different causes cannot have acted, independently or in concert, to produce extinction events.

The asteroid-impact theory has been applied to many mass extinctions since the discovery of Chicxulub. Most of the five major mass extinctions of the last 540 million years, and several of the smaller ones, have been shown to coincide in time with large impact craters or iridium spikes (layers of heightened iridium concentration) in the geological column.

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The Asteroid-impact Theory The primary cause of the Cretaceous mass extinction was a mystery for decades, until geologists discovered a thin layer of rock that marks the boundary between the Cretaceous period and following Tertiary period; this layer of sediments is termed the K-T boundary, and gave rise to the asteroid-impact theory of the Cretaceous extinction.

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Find out here! Learn the difference between weather and climate, and about the relationship between drought and the earth's water cycle.

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National Geographic Websites

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Fertile soils frequently blanket their slopes thanks to the slow breakdown of ancient volcanic rocks, which releases a host of nutrients vital for healthy crops and vineyards that produce flavorful grapes. Volcanoes also have deep roots in the history of civilizations, leading to their starring role in the spirituality and mythos of many cultures. And they spark the imagination, drawing numerous visitors to their flanks who feed a profitable industry in tourism. ( See dramatic photos of volcanoes around the world.)

Yet their fiery fits can be as dangerous as they are mesmerizing, sending rivers of molten rock and avalanches of searing ash and gas barreling down their sloping sides. So if you live near one of these mighty features-or plan to visit one on your next trip-here's some hazards to be aware of and steps you can take to stay safe during an eruption.

What are some eruption hazards?

Volcanoes pose an ever-shifting array of dangers, and each volcano is different. Some explode with fearsome force, like the 1980 eruption of Mount St. Helens. Other volcanoes send streams of lava flowing down their flanks, like what happened during Kilauea's 2018 eruption. And these dangers can spark many other issues including fires and flows of debris. The following are some of the many hazards volcanoes can pose:

Lava flows: These rivers of molten rock are extremely hot. While their exact temperature depends on their chemistry, lava flows can exceed a searing 2,000 degrees Fahrenheit-hot enough to melt copper. The temperature and chemistry also play into the lava's viscosity, which controls how fast it flows. While some can be readily out-walked, others rush surprisingly quickly. When Kilauea erupted in 2018, it was oozing lava near the vent at a rate of 15 miles per hour, faster than the vast majority of people can run.

Volcanic projectiles: These bits of searing hot rock are flung from active vents or volcanic craters. If they're larger than 2.5 inches across, they're dubbed lava bombs. While claims of refrigerator-sized lava bombs during Kilauea's 2018 eruption were overblown, these blazing blocks can be up to several yards across. And at sizzling hot temperatures, even small volcanic projectiles can be dangerous, setting fires, breaking bones, and melting human flesh.

Pyroclastic flows: Blistering-hot avalanches of gasses, rocks, and volcanic ash can barrel down a volcano's slopes, burying structures, sparking fires, and destroying everything in their path. They are extremely speedy, with some rushing as fast as 450 miles per hour. Pyroclastic flows can even travel uphill or cross water. Volcanoes that produce such flows are extremely dangerous. For example, pyroclastic flows abounded during the infamous eruption of Mount Vesuvious in 79 A.D. that devastated the city of Pompeii, Italy. ( Read about how Vesuvious may have killed its victims.)

Lahars or debris flows: This term describes a hot or cold slurry of water and rock fragments that rushes down a volcano's slopes like "rivers of concrete," according to the USGS. These often follow valleys or river channels and can move startlingly fast. While a lahar may start small, it can grow as it travels, carrying along any debris it encounters.

Toxic gases: Volcanoes also release toxic gasses, such as carbon dioxide, carbon monoxide, sulfur dioxide, and hydrogen chloride. Some of these, like sulfur dioxide, are extremely corrosive and can irritate the skin, eyes, and respiratory systems of hapless onlookers. In rare cases, the gasses can be deadly: A surge of carbon dioxide poured out of Africa's volcanic Lake Nyos in 1986, sweeping a nearby village and suffocating hundreds of people and cattle.

Volcanic ash: Unlike the fluffy bits that linger after a camp fire, volcanic ash is made up of tiny fragments of rock and shards of glass. It's damaging to lungs and can form a hefty blanket over nearby towns-even collapsing roofs of some structures. Ash can also shoot miles high into the sky and rain down for many miles around, posing a hazard for people quite far from an active volcano. ( Learn about how lightning can help signal the start of potentially dangerous eruptions of farflung volcanoes.)

What to do before an eruption?

Another vital preparation step is assembling an emergency kit that includes supplies like food, water, respiratory protection, eye protection, and a battery-powered radio. When preparing your kit, consider each member of your family and their needs- and don't forget your pets. The Department of Homeland Security has a detailed guide about putting together a kit for many different contingencies.

Even if you are just visiting a volcano for a day, make sure you are traveling with appropriate footwear, first aid supplies, and plenty of water.

What to do during an eruption?

If an evacuation seems on the horizon, the Centers for Disease Control recommends gathering additional supplies to keep in your vehicle, which should include flares, maps, basic tools, sleeping bags, and a fire extinguisher. When packing personal items, take only the essentials. And don't forget including at least a week's supply of any required prescription medications. If you don't own a vehicle, contact neighbors or others nearby who might be able to provide a ride in case you and your family need to leave.

What to do after an eruption?

Heed authorities' instructions for when it's safe to go back outside or return to your home. Alert family and friends of your status via text message or using the Red Cross' Safe and Well website. Avoid making phone calls unless it is an emergency as telecommunications are commonly very busy during and after disasters.

When it is safe to return home, check the structure and utilities for damage. The Red Cross has helpful guides that detail what to look for when returning after disaster. Also, document any damage in photos for insurance purposes.

Such powerful displays of Earth's fearsome force can be frightening, but with some preparation and close following of official instructions, you can reduce the risk of being blindsided by a blast.

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Fertile soils frequently blanket their slopes thanks to the slow breakdown of ancient volcanic rocks, which releases a host of nutrients vital for healthy crops and vineyards that produce flavorful grapes. Volcanoes also have deep roots in the history of civilizations, leading to their starring role in the spirituality and mythos of many cultures.

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The Effects of Cyclones on the Environment

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The Effects of Cyclones on the Environment

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The Effects of Cyclones on the Environment

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Breezy with a sturdy core - that's the trick to houses that can withstand cyclone-force winds.

By Natsumi Penberthy * Reading Time: 2 Minutes

HOUSES IN AUSTRALIA'S tropics have to be built to withstand winds of up to 310km/h. The key to protecting against the great sucking force or 'uplift pressures' created by cyclones, says Dr David Henderson of the Cyclone Testing Station at James Cook University, Queensland, is to ensure all the elements of the house are securely fixed together and down to the foundations.

The results speak for themselves: in the worst-hit areas of Queensland, 2011's Cyclone Yasi ripped off 20 per cent of roofs fitted in the 1980s, before cyclone-resistant building measures were implemented. Only 3 per cent of roofs installed afterwards were lost.

Building in wind resistance

1. DOORS are secured with barrel bolts. If a door facing into the wind fails, the positive pressure pushing on the outside suddenly enters the house, doubling the load on the roof, with potentially catastrophic consequences. Roller doors designed for cyclonic regions are recommended.

2. ROOFS are angled on all four sides. These fared better during Cyclone Yasi than gabled roofs angled on only two sides.

3. GUTTERING is firmly secured to the house. Water tanks, fences and sheds need strong foundations, as all can become missiles hurled at the house.

4. WINDOWS have mesh screens, bolted shutters and shatterproof glass.Opening windows on the downwind side to relieve pressure is dangerous, because wind can suddenly change direction.

5. FOOTINGS secure a house to the ground. They should be set to the recommended weight and depth.

6. A SHELTER ROOM with both reinforced concrete walls and ceiling, and stocked with supplies, provides a safe haven.

7. WATERPROOF SEALS and water-resilient walls stop rain being sucked in by pressure differences.

8. VENTS installed in the roof or eaves may reduce wind pressure created if a door or wall facing into the wind fails.

9. TREES and overhanging branches should be trimmed back well away from the house.

All clamped down

ROOF CLADDING gets sucked upward, so each tile or sheet of metal must be fastened to roof battens with screws or clips. Nails get ripped straight out.

REINFORCED STUD WALLS are the frame to which all cladding is attached. Large buildings have concrete blocks with reinforcing rods. Brick and mortar isn't strong enough to stand the uplift. pressure.

ROOF BATTENS should be firmly secured to the roof trusses with screws, and the trusses should be attached to the walls by straps or bolts.
This was article was originally published in AG#111. Source.

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How to cyclone-proof your house - Australian Geographic

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Breezy with a sturdy core - that's the trick to houses that can withstand cyclone-force winds. By Natsumi Penberthy * Reading Time: 2 Minutes HOUSES IN AUSTRALIA'S tropics have to be built to withstand winds of up to 310km/h.

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The effects of a tsunami on a coastline can range from unnoticeable to devastating. The effects of a tsunami depend on the characteristics of the seismic event that generated the tsunami, the distance from its point of origin, its size ( magnitude) and, at last, the configuration of the bathymetry (that is the depth of water in oceans) along the coast that the tsunami is approaching.

Small tsunamis, non-destructive and undetectable without specialized equipment, happen almost every day as a result of minor earthquakes and other events. They are very often too far away from land or they are too small to have any effect when they hit the shore. When a small tsunami comes to the shoreline it is often seen as a strong and fast-moving tide.

Tsunamis have long periods and can overcome obstacles such as gulfs, bays and islands. These tsunamis make landfall usually in the form of suddenly decreasing and then rapidly increasing water levels (not unlike a tidal bore) a combination of several large waves or bore-type waves. Generally tsunamis arrive, not as giant breaking waves, but as a forceful rapid increase in water levels that results in violent flooding.

However, when tsunami waves become extremely large in height, they savagely attack coastlines, causing devastating property damage and loss of life. A small wave only 30 centimetres high in the deep ocean may grow into a monster wave 30m high as it sweeps over the shore. The effects can be further amplified where a bay, harbour, or lagoon funnels the waves as they move inland. Large tsunamis have been known to rise to over 100 feet!

The amount of energy and water contained in a huge tsunami can cause extreme destruction when it strikes land.

The initial wave of a huge tsunami is extremely tall; however, most damage is not sustained by this wave. Most of the damage is caused by the huge mass of water behind the initial wave front, as the height of the sea keeps rising fast and floods powerfully into the coastal area. It is the power behind the waves, the endless rushing water that causes devastation and loss of life. When the giant breaking waves of a tsunami batter the shoreline, they can destroy everything in their path.

Destruction is caused by two mechanisms: the smashing force of a wall of water traveling at high speed, and the destructive power of a large volume of water draining off the land and carrying all with it, even if the wave did not look large.

Objects and buildings are destroyed by the sheer weight of the water, often reduced to skeletal foundations and exposed bedrock. Large objects such as ships and boulders can be carried several miles inland before the tsunami subsides.

Tsunami waves destroy boats, buildings, bridges, cars, trees, telephone lines, power lines - and just about anything else in their way. Once the tsunami waves have knocked down infrastructure on the shore they may continue to travel for several miles inland, sweeping away more trees, buildings, cars and other man made equipment. Small islands hit by a tsunami are left unrecognizable.

Especially along a high seismic area, known as the Ring of Fire, tsunamis may have dramatic consequences as they hit less developed countries.

The buildings infrastructure in these poorer nations are not well built and cannot withstand the impact of the tsunami. Whole areas and towns are a picture of destruction as the tsunami leaves at trail devastation and misery behind it.

One of the biggest and worst effects of a tsunami is the cost to human life because unfortunately escaping a tsunami is nearly impossible. Hundreds and thousands of people are killed by tsunamis. Since 1850 alone, tsunamis have been responsible for the loss of more than 430,000 lives. There is very little warning before a tsunamis hits land. As the water rushes toward land, it leaves very little time to map an escape plan.

People living in coastal regions, towns and villages have no time to escape. The violent force of the tsunami results in instant death, most commonly by drowning. Buildings collapsing, electrocution, and explosions from gas, damaged tanks and floating debris are another cause of death. The tsunami of December 2004 that struck South East Asia and East Africa killed over 31,000 people in Sri Lanka only, leaving 23,000 injured.

Tsunami waves and the receding water are very destructive to structures in the run-up zone. The areas close to the coast are flooded with sea water, damaging the infrastructure such as sewage and fresh water supplies for drinking.

Flooding and contamination of drinking water can cause disease to spread in the tsunami hit areas. Illnesses such as malaria arise when water is stagnant and contaminated. Under these conditions it is difficult for people to stay healthy and for diseases to be treated, so infections and illnesses can spread very quickly, causing more death.

Tsunamis not only destroy human life, but have a devastating effect on insects, animals, plants, and natural resources. A tsunami changes the landscape. It uproots trees and plants and destroys animal habitats such as nesting sites for birds. Land animals are killed by drowning and sea animals are killed by pollution if dangerous chemicals are washed away into the sea, thus poisoning the marine life.

The impact of a tsunami on the environment relates not only to the landscape and animal life, but also to the man-made aspects of the environment. Solid waste and disaster debris are the most critical environmental problem faced by a tsunami-hit country.

Recycling and disposal of this waste in an environmentally sensitive manner where possible (crushing concrete, bricks, etc. to produce aggregate for rebuilding and road reconstruction) are critical.

Combined with the issue of waste is that of hazardous materials and toxic substances that can be inadvertently mixed up with ordinary debris. These include asbestos, oil fuel, and other industrial raw materials and chemicals. Rapid clean-up of affected areas can result in inappropriate disposal methods, including air burning and open dumping, leading to secondary impacts on the environment.

Contamination of soil and water is the second key environmental impact of a tsunami. Salination of water bodies such as rivers, wells, inland lakes, and groundwater aquifers can occur in most cases. This also affects the soil fertility of agricultural lands, due to salination and debris contamination, which will affect yields in the medium and long term. Sewage, septic tanks and toilets are damaged contaminating the water supply.

Last but not least, there may be radiation resulting from damage to nuclear plants, as it happened in Japan in March 2011. Since radiation exists for a long time, it has the capacity to inflict damage upon anything exposed to it. Radiation is most dangerous to animals and humans causing destruction as molecules loose their electrons. The damage caused by radiation to the DNA structure determines birth defects, cancers even death.

Massive costs hit communities and nations when a tsunami happens. Victims and survivors of the tsunami need immediate help from rescue teams.

Governments around the world may help with the cost of bringing aid to devastated areas. National institutions, the United Nations, other international organizations, community groups and NGOs , and a variety of other entities come together to provide different kinds of aid and services. There might also be appeals and donations from people who have seen pictures of the area in the media.

Reconstruction and clean up after a tsunami is a huge cost problem. Infrastructure must be replaced, unsafe buildings demolished and rubbish cleared. Loss of income in the local economy and future losses from the destruction of infrastructure will be a problem for some time to come.

The total financial cost of the tsunami could be millions or even billions of dollars of damage to coastal structures and habitats. It is difficult to put an exact figure on the monetary cost but the cost may represent an important share of a nation's GDP.

Victims of tsunami events often suffer psychological problems which can last for days, years or an entire lifetime. Survivors of the Sri Lankan tsunami of December 2004 were found to have PTSD (post traumatic stress disorder) when examined by the World Health Organization (WHO): 14% to 39% of these were children, 40% of adolescents and 20% of mothers of these adolescents were found to have PTSD 4 months after the tsunami.

These people were suffering from grief and depression as their homes, businesses and loved ones were taken from them. Many still had PTSD. Periliya Village counts 2,000 dead and 400 families became homeless. These people were found to still have psychological problems 2 years after the tsunami.

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tsunamis effects destruction death environmental impacts

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video earthquake tsunamis 2011 japan destruction

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Tsunami | Effects, large destruction of property and loss of life

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The effects of a tsunami on a coastline can range from unnoticeable to devastating. The effects of a tsunami depend on the characteristics of the seismic event that generated the tsunami, the distance from its point of origin, its size ( magnitude) and, at last, the configuration of the bathymetry (that is the depth of water in oceans) along the coast that the tsunami is approaching.

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Australian Government Website

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We operate the National Earthquake Alerts Centre to provide around the clock monitoring, analysis and alerting of significant earthquakes. This program provides alerts of earthquakes that have the potential to generate tsunami that could impact Australia's coastline.

We provide nationally consistent methodologies for estimating the frequency of tsunamis offshore, which are widely used to inform site-specific tsunami inundation hazard assessments. We also conduct onshore hazard assessments and work with governments and the emergency management sector to inform risk mitigation strategies

To help understand what could be at threat from tsunami, we provide about buildings, demographics, community infrastructure and agricultural commodities.

We also provide around the clock access to data about people, property and infrastructure potentially exposed during an event. Our information aids in providing an understanding of a tropical cyclone situation to targeted preparedness, response and recovery efforts.

Our products, tools and data provide a better understanding of hazard vulnerabilities for all sectors to plan, prepare and reduce exposure to natural hazards improving preparedness now and into the future.

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Tsunami | Community Safety | Geoscience Australia

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Our team supports Australia's ability to manage the impact of tsunami and helps inform decisions about risk.

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Australian Government Website

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What is a bushfire?

Bushfires and grassfires are common throughout Australia. Grassfires are fast moving, passing in five to ten seconds and smouldering for minutes. They have a low to medium intensity and primarily damage crops, livestock and farming infrastructure, such as fences. Bushfires are generally slower moving, but have a higher heat output. This means they pass in two to five minutes, but they can smoulder for days. Fire in the crown of the tree canopy can move rapidly.

Bushfires are an intrinsic part of Australia's environment. Natural ecosystems have evolved with fire, and the landscape, along with its biological diversity, has been shaped by both historic and recent fires. Many of Australia's native plants are fire prone and very combustible, while numerous species depend on fire to regenerate. Indigenous Australians have long used fire as a land management tool and it continues to be used to clear land for agricultural purposes and to protect properties from intense, uncontrolled fires.

Historically, bushfires have caused loss of life and significant damage to property. While naturally occurring bushfires cannot be averted, their consequences can be minimised by implementing mitigation strategies and reducing the potential impact to areas which are most vulnerable

What factors create a favourable environment for bushfires to occur?

The basic factors which determine whether a bushfire will occur include the presence of fuel, oxygen and an ignition source. The fire intensity and speed at which a bushfire spreads will depend on ambient temperature, fuel load, fuel moisture, wind speed and slope angle.

Fuel load

Fuel load describes the amount of fallen bark, leaf litter and small branches accumulating in the landscape. Generally speaking, the greater the fuel load, the hotter and more intense the fire. Fuel which is concentrated but loosely compacted will burn faster than heavily compacted or scattered fuel sources. Smaller pieces of fuel such as twigs, leaf litter and branches burn quickly, particularly when they are dry and loosely arranged and will burn quickly in the fire front. Larger fuels, such as tree trunks often burn later after the fire front has passed. The natural oil within eucalypt trees promotes the combustion of fuel.

Fuel moisture

Dry fuel will burn quickly, but damp or wet fuel may not burn at all. As a consequence, the time since rainfall and the amount of rain received is an important consideration in assessing bushfire danger. Often a measure of the drought factor, or moisture deficit, will be used as an indicator of extreme bushfire weather conditions.

Wind speed

Wind acts to drive a fire by blowing the flames into fresh fuel, bringing it to ignition point and providing a continuous supply of oxygen. Wind also promotes the rapid spread of fire by spotting, which is the ignition of new fires by burning embers lofted into the air by wind. Spotting can occur up to 30km downwind from the fire front.

There is a threshold wind speed of around 12 to 15km/h which makes a significant difference in the behaviour of bushfires in the open. When wind speeds are below this threshold, fires with heavy fuel loads burn slowly. However, even a slight increase in wind speed above this threshold results in a significant increase in fire behaviour and advancement. The width of a fire front also has an influence on the rate of spread and a wind shift can immediately widen the forward edge of a fire.

Ambient temperature

The higher the temperature the more likely it is that a fire will start or continue to burn. This is because the fuel is closer to its ignition point at high temperatures and pre-heated fuel loads burn faster.

Relative humidity

Dry air promotes a greater intensity fire than moist air. Plants become more flammable at a low humidity because they release their moisture more easily.

Slope angle

Fires pre-heat their fuel source through radiation and convection. As a result, fires accelerate when travelling uphill and decelerate travelling downhill. The steepness of the slope plays an important role in the rate of fire spread. The speed of a fire front advancing will double with every 10 degree increase in slope, so that on a 20 degree slope, its speed of advance is four times greater than on flat ground.

Ignition Source

Bushfires can originate from both human activity and natural causes with lightning the predominant natural source, accounting for about half of all ignitions in Australia. Fires of human origin currently account for the remainder and are classified as accidental or deliberate. Fires lit deliberately can be the result of arson or might be designed to achieve a beneficial outcome but conditions have changed, resulting in uncontrollable spread.

Unfortunately deliberate and accidentally lit fires are more prevalent near populated areas and have a disproportionately higher risk of infrastructure impact. Arsonists place people and property at serious and unnecessary risk, particularly when igniting fires on extreme fire weather days.

Where do bushfires occur?

The Australian climate is generally hot, dry and prone to drought. At any time of the year, some parts of Australia are prone to bushfires. The widely varied fire seasons are reflected in the continent's different weather patterns. For most of southern Australia, the danger period is summer and autumn. For New South Wales and southern Queensland, the peak risk usually occurs in spring and early summer. The Northern Territory experiences most of its fires in winter and spring.

Grassland fires frequently occur after good periods of rainfall which result in abundant growth that dries out in hot weather. Bushfires tend to occur when light and heavy fuel loads in Eucalypt forests have dried out, usually following periods of low rainfall.

The potential for extreme fire weather varies greatly throughout Australia, both in frequency and severity. When potential extreme fire weather is experienced close to populated areas, significant loss is possible. In terms of the total area burnt, the largest fires are in the Northern Territory and northern areas of Western Australia and Queensland. Most loss of life and economic damage occurs around the fringes of cities where homes are commonly in close proximity to flammable vegetation.

In the years between 1967 and 2013, major Australian bushfires have resulted in over 8000 injuries and 433 fatalities, close to 50 per cent of all deaths from major Australian natural disasters in the period (excluding heatwaves). Over this same period, bushfires cost approximately A$4.7 billion (2013 Australian dollars, including deaths and injuries but excluding most indirect losses).

A fire front advances more quickly when travelling upslope and slows travelling down slope. The speed of a fire front advancing will double for every 10 degree increase in slope, so that on a 20 degree slope, its speed is four times greater than over flat ground.

References:

Ladds M, Keating A, Handmer J and Magee L (2017)How much do disasters cost? A comparison of disaster cost estimates in Australia. International J of DRR. 10.1016/j.ijdrr.2017.01.004

Ladds, MA, Magee, L, Handmer, J (2015) AUS:DIS - Database of losses from disasters in Australia 1967-2013. https://github.com/liammagee/sealand

John Handmer, Monique Ladds and Liam Magee (December 2016), Disaster losses from natural hazards in Australia, 1967-2013. (Report with AGD)

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Geoscience Australia is the national public sector geoscience organisation. Its mission is to be the trusted source of information on Australia's geology and geography to inform government, industry and community decision-making. The work of Geoscience Australia covers the Australian landmass, marine jurisdiction and territories in Antarctica.

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Australian Government Website

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We operate the National Earthquake Alerts Centre to provide around the clock monitoring, analysis and alerting of significant earthquakes to the emergency management sector. To help understand what could be at threat from earthquakes, we provide about buildings, demographics, community infrastructure and agricultural commodities.

Our nation-wide seismic hazard assessment defines the level of earthquake ground shaking across Australia that has a specified likelihood of being exceeded across a given time period.

This information is used by building standards and decision makers to develop mitigation strategies so that communities can be more resilient to earthquake events.

We also use this information to provide advice to government on seismic hazards that may impact infrastructure projects for a low-carbon economy.

We also provide around the clock about people, property and infrastructure potentially exposed. Our information aids in providing an understanding of the situation to targeted preparedness, response and recovery efforts.

Our products, tools and data provide a better understanding of hazard vulnerabilities for all sectors to plan, prepare and reduce exposure to natural hazards improving preparedness now and into the future.

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Earthquake | Community Safety | Geoscience Australia

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We operate the National Earthquake Alerts Centre to provide around the clock monitoring, analysis and alerting of significant earthquakes to the emergency management sector. To help understand what could be at threat from earthquakes, we provide about buildings, demographics, community infrastructure and agricultural commodities.

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ABC Website

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Posted November 27, 2019 12:59:05

Dust storms have become part of daily life in central-west New South Wales, as wind whips up dry soil and sends it flying.

Mark Swift has watched as it has blown onto his property and he has noted how "constant" it has become.

"It can't be good for your health," he said.

But Mr Swift, and his wife Katrina Swift, were most concerned about the environmental damage of the dust storms, as precious topsoil disappears from their farming region and beyond.

"We thought the noughties' drought was bad," he said.

"I'd have it back any day of the week at the moment compared to what we're dealing with."

Investing in drought-tolerant technologies

Since that notorious drought, their family business has made significant changes.

Mr Swift has de-stocked and invested in new research and technology to help improve soil quality.

"It's a whole range of things. It's stubble retention, managing fallows over summer where we control weeds where we're not growing crops, and it's less disturbance of our soil," he said.

"It's also what goes on in the background, like breeding programs to improve the resilience of our seed varieties."

And Mr Swift said the results spoke for themselves.

"We're growing more grain now than we were in previous droughts that we thought were pretty bad," he said.

Technology like soil probes have been helping with testing moisture levels, allowing the couple to make educated decisions on when and what to plant.

Ms Swift said the other big lesson was to keep some crop, or cover, on the ground.

"Groundcover is key in extreme conditions like this," she said.

"It stops wind erosion, water erosion, and holds the soil particles together."

The barley crop the family managed to grow this year has been poor quality.

But instead of cutting it for hay to make quick cash it has been left to shade the ground.

As a result there was no dust.

"It also means our soil microbes and things can survive year on year, and we haven't got to re-establish a whole ecosystem underneath the ground again when the drought breaks," Ms Swift said.

No-till farming for surviving drought

Most farmers are desperate to avoid seeing their paddocks become a dustbowl, including John Gladigau, who has been farming with business partner, Robin Schaefer, on the sandy soils of Loxton in the South Australian Mallee region.

He recalled that during the 1982 drought there was "not a blade of grass" on the farm.

"There was nothing. It was just erosion. That was it," Mr Gladigau said.

Since then the business has invested hundreds of thousands of dollars in no-till farming, or growing crops without disturbing the soil.

And the picture now is very different.

"So this year, while we still have some eroded patches, we could argue that 95 per cent of our farming area is covered [and] isn't eroded - isn't blowing away," Mr Gladigau said.

While the machinery required for no-till farming has been expensive, Mr Schaefer said the long-term environmental benefits made it worthwhile.

"It enables us to be able to plant our crops dry because we know they're not going to get blasted by wind with any sand, or anything [else]," he said.

"And they're protected in amongst the stubble, and so that enables us to make use of every single drop of rain that falls.

"So as soon as the first rain comes, the plants get up and germinate and get up [and] start growing."

It is why they would like to see farmers rewarded for looking after the land.

Progressive farming finds environmental solutions

Australian Farm Institute executive director, Richard Heath, said some progressive farmers had been making the most of a "small number of grants and schemes" available, but the market needed to be expanded.

"The sorts of services that are delivered from farmland are sequestering carbon, delivering clean air and clean water," he said.

"That adds to tourism value and the value of the landscape.

"There are lots of ways those services can be monetised or valued in a way that rewards farmers for protecting them ... which is obviously of great benefit for reducing greenhouse gas emissions."

The Federal Government is in the early stages of developing a $34-million trial to give farmers money to improve biodiversity on farms.

Mr Swift said such an approach would be critical for future generations because farmers managing in this drought would struggle without significant rainfall next year.

"I don't know what we'll do," he said.

"There won't be groundcover anywhere."

Topics: government-and-politics, agricultural-crops, greenhouse-gas, federal-government, drought, australia, longreach-4730, dubbo-2830, sale-3850, ensay-3895, orbost-3888, australia, vic, nsw, bedourie-4829, windorah-4481, st-george-4487, hughenden-4821, winton-4735, boulia-4829, mount-isa-4825, barcaldine-4725, quilpie-4480, blackall-4472, cunnamulla-4490, charleville-4470, goulburn-2580, wollongong-2500, moree-2400, parkes-2870, gunnedah-2380, griffith-2680, walgett-2832, bourke-2840, wagga-wagga-2650, muswellbrook-2333, orange-2800, tamworth-2340, broken-hill-2880, peterborough-5422, pinnaroo-5304, darke-peak-5642, yunta-5440, elliston-5670, streaky-bay-5680, kimba-5641, loxton-5333, orroroo-5431, kadina-5554, whyalla-5600, marree-5733, cleve-5640, port-pirie-5540

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How grain growers are still harvesting crops in drought

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Posted November 27, 2019 12:59:05 Dust storms have become part of daily life in central-west New South Wales, as wind whips up dry soil and sends it flying. Mark Swift has watched as it has blown onto his property and he has noted how "constant" it has become.

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Blizzards: Formation, Effects and Facts | Conserve Energy Future

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A blizzard is a weather event that includes low temperatures, wind speeds greater than 56 kilometers (35 miles) per hour, and a large amount of falling or blowing snow that lowers visibility to 0.4 kilometers (0.25 mile) for a minimum of three hours.

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HOW DO TORNADOES EFFECT THE EARTH'S SURFACE? Lily and Olivi by Elizabeth Harris

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TOUCH this image to discover its story. Image tagging powered by ThingLink

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Weather Wiz Kids

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Tornadoes

What is a tornado?
A tornado is a violent rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of up to 300 mph. They can destroy large buildings, uproot trees and hurl vehicles hundreds of yards. They can also drive straw into trees. Damage paths can be in excess of one mile wide to 50 miles long. In an average year, 1000 tornadoes are reported nationwide.

How do tornadoes form?

Most tornadoes form from thunderstorms. You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. When these two air masses meet, they create instability in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.

Click Here to learn more about tornadoes from NOAA.

What are some other factors for tornadoes to form?
Several conditions are required for the development of tornadoes and the thunderstorm clouds with which most tornadoes are associated. Abundant low level moisture is necessary to contribute to the development of a thunderstorm, and a "trigger" (perhaps a cold front or other low level zone of converging winds) is needed to lift the moist air aloft. Once the air begins to rise and becomes saturated, it will continue rising to great heights to produce a thunderstorm cloud, if the atmosphere is unstable. An unstable atmosphere is one where the temperature decreases rapidly with height. Atmospheric instability can also occur when dry air overlays moist air near the earth's surface. Finally, tornadoes usually form in areas where winds at all levels of the atmosphere are not only strong, but also turn with height in a clockwise or veering direction.

What do tornadoes look like?
Tornadoes can appear as a traditional funnel shape, or in a slender rope-like form. Some have a churning, smoky look to them, and other contain "multiple vortices", which are small, individual tornadoes rotating around a common center. Even others may be nearly invisible, with only swirling dust or debris at ground levels as the only indication of the tornado's presence.

What is a funnel cloud? A funnel cloud is a rotating cone-shaped column of air extending downward from the base of a thunderstorm, but not touching the ground. When it reaches the ground it is called a tornado.

It is not fully understood about how exactly tornadoes form, grow and die. Tornado researchers are still trying to solve the tornado puzzle, but for every piece that seems to fit they often uncover new pieces that need to be studied. How do tornadoes stop?

A supercell thunderstorm is a long-lived thunderstorm whose updrafts and downdrafts are in near balance. These storms have the greatest tendency to produce tornadoes that stay on the ground for long periods of time. Supercell thunderstorms can produce violent tornadoes with winds exceeding 200 mph.
What is a supercell thunderstorm?

A mesocyclone is a rotating vortex of air within a supercell thunderstorm. Mesocyclones do not always produce tornadoes.
What is a mesocyclone?

A wall cloud is an abrupt lowering of a rain-free cumulonimbus base into a low-hanging accessory cloud. A wall cloud is usually situated in the southwest portion of the storm. A rotating wall cloud usually develops before tornadoes or funnel clouds. What is a microburst?
A microburst is a downdraft (sinking air) in a thunderstorm that is less than 2.5 miles in scale. Although microbursts are not as widely recognized as tornadoes, they can cause comparable, and in some cases, worse damage than some tornadoes produce. In fact, wind speeds as high as 150 mph are possible in extreme microburst cases.
What is a wall cloud?

A waterspout is just a weak tornado that forms over water. They are most common along the Gulf Coast. Waterspouts can sometimes move inland, becoming tornadoes causing damage and injuries.

What is a waterspout?

What is hail?
Hail is created when small water droplets are caught in the updraft of a thunderstorm. These water droplets are lifted higher and higher into the sky until they freeze into ice. Once they become heavy, they will start to fall. If the smaller hailstones get caught in the updraft again, they will get more water on them and get lifted higher in the sky and get bigger. Once they get lifted again, they freeze and fall. This happens over and over again until the hailstone is too heavy and then falls to the ground.

What is the largest hailstone recorded in the United States?
According to the National Weather Service, the largest hailstone is 8 inches in diameter and weights approximately 2 pounds. It fell in Vivian, South Dakota on July 23, 2010.
A gustnado is a short-lived, relatively weak whirlwind that forms along a gust front. A gust front is the surge of very gusty winds at the leading edge of a thunderstorm's outflow of air. Gustnadoes are not tornadoes. They do not connect with any cloud-base rotation. But because gustnadoes often have a spinning dust cloud at ground level, they are sometimes wrongly reported as tornadoes. Gustnadoes can do minor damage.

What is a gustnado?
A landspout is a very weak tornado that is not associated with a wall cloud or a mesocyclone. It is the land equivalent of a waterspout.

What is a landspout?
A dust devil generally forms in the hot sun during the late morning or early afternoon hours. These are mostly harmless whirlwinds and are triggered by light desert breezes that create a swirling plume of dust with speeds rarely over 70 mph. These differ from tornadoes in that they are not associated with a thunderstorm (or any cloud) and are usually very weak.

What is a dust devil? Tornadoes can happen at any time of the year and at any time of the day. In the southern states, peak tornado season is from March through May. Peak times for tornadoes in the northern states are during the summer. A few southern states have a second peak time for tornado outbreaks in the fall. Tornadoes are most likely to occur between 3 p.m. and 9 p.m.

The geography of the central part of the United States, known as the Great Plains, is suited to bring all of the ingredients together to forms tornadoes. More than 500 tornadoes typically occur in this area every year and is why it is commonly known as "Tornado Alley". Texas, Oklahoma, Kansas, Nebraska, South Dakota, North Dakota, Iowa, Missouri, Arkansas and Louisiana all make up Tornado Alley. When are tornadoes most likely to occur?

Where are tornadoes most likely to occur?

Know the Lingo

TORNADO WATCH - Tornadoes are possible in your area. Stay tuned to the radio or television news.
TORNADO WARNING - A tornado is either on the ground or has been detected by Doppler radar. Seek shelter immediately!

Click Here to see if there are any active warnings in your area.

Know the Facts
Tornadoes can occur at any time of the year. nd winds less than 110 mph.

No terrain is safe from tornadoes.

Never open windows in severe weather situations. This allows damaging wind and debris to enter the structure.

69% of all tornadoes are labeled "weak tornadoes" meaning they have a lifetime of 1-10+ minutes a

SCALE

WIND SPEED

POSSIBLE DAMAGE

Enhanced,
Operational
Fujita Scale

29% of all tornadoes are labeled "strong tornadoes" meaning they last 20 minutes or longer and winds reach 110-205 mph.
2% of all tornadoes are labeled "violent tornadoes" and can last over an hour.

Fujita Scale of Tornado Intensity

Tornado Safety Tips
BEFORE A TORNADO: Have a disaster plan. Make sure everyone knows where to go in case a tornado threatens. Make sure you know which county or parish you live in. Prepare a kit with emergency food for your home. Have enough food and water for at least 3 days.

AFTER A TORNADO: Stay indoors until it is safe to come out. Check for injured or trapped people, without putting yourself in danger. Watch out for downed power lines. Use a flashlight to inspect your home. Tornado Activities

Lesson Plan: Here are some great lesson plans on learning about tornado safety. Note: This is a PDF file, so you need to have Adobe Acrobat Reader. DURING A TORNADO: Go to a basement. If you do not have a basement, go to an interior room without windows on the lowest floor such as a bathroom or closet. If you can, get under a sturdy piece of furniture, like a table. If you live in a mobile home get out. They offer little protection against tornadoes. Get out of automobiles. Do not try to outrun a tornado in your car, leave it immediately. If you're outside, go to a ditch or low lying area and lie flat in it. Stay away from fallen power lines and stay out of damaged areas.
Tornado Experiment: Here is a great experiment that allows the kids to make a tornado in a bottle.
IF YOU'RE AT SCHOOL DURING A TORNADO: Every school should have a disaster plan and have frequent drills. Basements offer the best protection. Schools without basements should use interior rooms and hallways on the lowest floor away from windows. Crouch down on your knees and protect your head with your arms.
Tornado Experiment: Here is a great experiment that allows the kids to make a tornado in a jar.
Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!
Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer.

Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Child project

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Do tornadoes in any way change the landscape?
- Tornadoes effect the environment by destroying buildings and trees.Tornadoes destroy our farms, which means there will be food shortages around the surrounding area. Tornadoes can cause water contamination, which poses a serious problem, as plants, animals, and humans are effected by this. Fires may occur after a tornado. It can give off carbon dioxide into our atmosphere.

Define weathering, erosion, and deposition.
-Weathering is the chemical and physical processes that change the characteristics of rocks on the Earth's surface.
-Erosion refers to the transportation of rock, soil, and mineral particles from one location to another.
-Deposition is where rock particles that are picked up and transported by one of the eroding agents will ultimately be deposited somewhere else.

Do tornadoes cause or promote weathering, erosion, and deposition?
-Yes, tornadoes cause weathering, erosion, and deposition. Large trees can be pulled out of the ground and carried away by the tornado to another location. The loss of vegetation could contribute to soil erosion.

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How Tornadoes Change The Landscape in Weathering, Erosion, and Deposition

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Do tornadoes in any way change the landscape? - Tornadoes effect the environment by destroying buildings and trees.Tornadoes destroy our farms, which means there will be food shortages around the surrounding area. Tornadoes can cause water contamination, which poses a serious problem, as plants, animals, and humans are effected by this.

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Child Project

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Tornadoes effect the environment by destroying buildings and trees. Tornadoes also kill animals, which effects the food chain and disrupts the whole environment. Tornadoes destroy our farms, which means there will be food shortages around the surrounding area. After everything is destroyed, humans have to rebuild. Tornadoes can cause water contamination, which poses a serious problem, as plants, animals and humans are effected by this. Debris can be very dangerous, as it could kill plants and animals very easily. Some trees take over 100 years to grow, so if they are destroyed, they will be hard to replace. Fires may occur after a tornado due to damaged power lines and gas leaks. Fire contributes to global warming by giving off carbon dioxide into the atmosphere. Because of man-made global warming, scientists believe that there will be an increases in tornadoes and other severe weather. What do you think?

Here is an example of how much damage a tornado can do:

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Tornadoes effect the environment by destroying buildings and trees. Tornadoes also kill animals, which effects the food chain and disrupts the whole environment. Tornadoes destroy our farms, which means there will be food shortages around the surrounding area. After everything is destroyed, humans have to rebuild.

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Good information

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What causes tsunami and how can we prepare?