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Behind the News is a fun, accessible way for upper primary and secondary students to learn about what’s happening in the world around them.

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NATASHA THIELE, REPORTER: This is what a tsunami can look like. Huge waves that sweep across the ocean and onto land, destroying buildings and lives. The waves are so strong; they can travel faster than a jet plane!

Tsunamis are caused by sudden movement on the ocean floor, either from earthquakes, volcanoes or underwater landslides. In this case, the tsunami was triggered by a quake.

About 90 percent of all quakes happen around a place called the 'ring of fire', a circle around the Pacific Ocean. It's home to about three-quarters of the world's volcanoes and some of the biggest eruptions.

You see, the earth's made up of what are called 'tectonic plates'. They're a bit like this jigsaw puzzle of the world, floating in this pool. The plates are constantly moving, something like a few centimetres a year! Usually we don't feel a thing, but if the plates crash into each other quickly or rub against each other, they can create an earthquake.

But not just any earthquake can cause a tsunami, first it has to happen under the ocean. Imagine these bricks are like two plates on the ocean floor. If one of them suddenly does this, it'll push water high up into the air. And when that happens, the water surges towards the coast, gaining size and more speed as the water becomes shallow.

In this tsunami, waves got up to three metres high. A huge tsunami happened near Sumatra back in 2004. It damaged lots of countries near the 'Ring of Fire'. It killed more than 225,000 people in 14 countries. Following the tragedy, governments promised early warning systems would be improved.

Special sensors and equipment are in place to let people know when and where a tsunami is likely to hit. The Pacific Tsunami Warning Centre tracks earthquakes, using things like seismographs, and sends out warnings. Beaches and nearby areas are evacuated and everyone is moved to higher ground for their safety.

Even with warning systems in place, it's sometimes impossible for people to reach safety, because they live too close to where it's happened. Unfortunately in this case, there were sensors to detect a tsunami, but they'd been vandalised or stolen.

Some countries are concerned warnings aren't going out early enough. There have been times when warnings have been issued and nothing serious has happened. Scientists say they're working to improve the system, but they can't take any chances.

They say it's better to evacuate everyone, even if it's sometimes a false alarm, because if a bad tsunami did hit the consequences would be terrible.

Although experts say Australia's at a very low risk of being hit by a massive quake or a tsunami, it's still good to know the warning systems are there to alert us if something happens.

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We've yet again been reminded of the devastating force of a tsunami. Last week the Indonesian island of Sumatra was hit after a massive earthquake triggered a wave that killed hundreds of people. And some are still missing. So how do tsunamis happen and what systems are in place to help save lives.

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With so many big storms about, we find out more about cyclones and how they work.

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Justina Ward, BTN Reporter: In Australia, we tend to see a lot of these, bushfires. Yeah, we're one of the most fire prone countries in the world seeing around 45 to 60-thousand bushfires every year. But have you ever wondered how or why bushfires start in the first place? Let's find out. Perhaps a good place to start is to understand what fire is. To exist, this wavy, hot, thing actually relies on three ingredients. Heat, oxygen and fuel. What's fuel? Well, it's basically anything that burns. And when these three things combine it causes a special type of chemical reaction called combustion. This reaction usually releases heat and light, which is the flame thing. And because heat is both an ingredient and a product, fire is a self-sustaining chain reaction that continues until it runs out of fuel or oxygen! So basically, a fire needs a spark. But how does that happen somewhere like here?

Sandy Whight, AFAC Executive Director National Capability, AFAC: There's many factors for how bushfires start. It can be deliberate arson, a lot of it's carelessness. The other big cause of bushfires in Australia is dry lightning strikes. Honestly I would say, the majority of fires are because of humans.

And because our continent is so hot and dry and prone to drought, meaning there's not a lot of moisture in the environment, it makes it a lot easier for fuel to ignite and burn.

Mika Peace, Senior Fire Weather Researcher, BOM: We have a lot of bushfires in Australia, because the landscapes evolved with fire, we tend to have relatively wet winters and then during the summer months as things dry out you've got vegetation that becomes flammable and ready to burn.

So how does a bushfire spread? Well, a lot of it has to do with the vegetation, the weather and the shape of the land.

Hey Robbie, how are you going?

But to understand this better, I caught up with Robbie who's a rural firefighting training officer.

So um, what do we have here?

Robin Geytenbeek, Team Leader Rural Firefighting Training, CFS: Okay, so this is a um, burn table. We use it to teach our students a bit about fire behaviour. So, say a lightning strike, there's no wind here in this situation, so the fire's just going to burn out in a sort of circular pattern. Now the other thing that can affect fire, the two main things, is the wind or slope. So, what I can do here is light another fire on a 20 degree slope and we see, this is where we lit the fire, and we see how we've actually got 3 or 4 times more distance than this side than the backing or the flank fires.

So, can you explain why fire travels faster up a slope?

Robin: Yeah, certainly that's a good question. When you have a fire being up slope, the heat coming off the fire actually pushes through the fuel in front of the fire and therefore that accelerates the fire of that direction.

The shape of a fire and how many there, are can also influence how a fire might behave.

The flames are pretty high!

Robin: Absolutely, so that's where we're saying, because it's a line of fire for one thing and the slope, means the fire behaviour, the intensity is going to be quite large, so you can see the lengthening through there, that's all the preheating happening that we talked about before, and so that accelerates the fire up.

Why do the flames react that way in leaning into each other?

Robin: It's called junction zoning, basically what happens is that the convection pulls together, so instead of two separate convection columns, we have them both join together so that it doubles the, the intensity. And there goes our fire.

I'm glad it's only that size.

Robin: Yeah.

Yeah, luckily this fire was in a controlled environment. But if a fire was somewhere like here and we added a bit of wind, well it would be a different story. You see, strong winds are another big reason to how bushfires spread because by providing more oxygen, it increases the intensity, and a change of wind direction can make the fire a lot bigger really quickly.

Fire fighter: Yeah spot fires galore down here. We're talking about 60 to 70 flame heights, 60, 70 flame height.

In some cases, bushfires can get so big and generate so much power, they can even create their own weather.

Mika: In what the fire is doing is it's producing enough energy in an unstable atmosphere, that the fire's convection column or the smoke plume grows vertically. And then, the fire can actually generate a fire thunderstorm cloud over the top of it. And in the extreme events, of course, we can see these fire generated thunderstorms or Pyrocumulonimbus clouds can actually ignite new fires downwind.

Another fire spreader are embers, which are burning materials like leaves, twigs and bark, and can start spot fires kilometres away. Not to mention the radiant heat that comes from a bushfire. It can be so intense, that the fuel around it can self-ignite.

Sandy: If they're particularly dry and fine fuels, they will start to burn themselves. So that is one of the ways the fire accelerates, it's also what makes it so dangerous for us and for animals.

So, with all this in mind, how do we manage or prevent bushfires? Well, one way is to quite literally fight fire with fire. We see this with prescribed burns, which involves strategically setting planned fires to reduce the amount of fuel in the landscape, something that's been practiced in Australia for tens of thousands of years.

Oliver Costello, Cultural Fire Practitioner: Cultural burning was the First Nations Aboriginal people, Indigenous people's way of burning the country. We call it cultural because it's a part of the culture of the land and the people's relationship. Culturally we try and keep the fire intensity quite low, because we want to protect the canopy and if we do our burning early in the cooler times when the lightning strike, the fire won't be so bad because we've done all that good fire, or that cultural fire around the landscape.

You see, unlike hot fire, which can kill plants and cause thick, hazardous regrowth, cool fire gently removes fine fuels at lower temperatures, propagates fire-dependent plant species, and allows animals to safely move away from the heat.

Mika Peace, Senior Fire Weather Researcher, Bureau of Meteorology: So there's a lot of work that's happening across Australia at the moment in Indigenous fire regimes and trying to say how can we actually put good fire low intensity fire back into the landscape and make sure that we're nurturing the landscape instead of letting the fuel loads accumulate.

There are a lot of things we can do too, like keeping fuel loads low around the house, avoid doing activities that could cause an unwanted fire, paying attention to weather conditions, and if you're in a bushfire prone area, having a bushfire survival plan so you know exactly what to do if you need to get to a safe place.

Sandy: This is a this is part of how we live and where we live. We learn about the science so that we can look after things properly, so that we can make good decisions so that we can provide appropriate warnings and advice to communities for how to keep themselves safe to make predictions, and that's why it's important we understand the science of bushfires.

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what is fire? what is a bushfire? indigenous land management

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The Science of Bushfires - Behind The News

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Bushfires happen a lot in Australia, but have you ever wondered why?

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Japanese Earthquake Technology "Base Isolation"

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Japanese Earthquake Technology "Base Isolation"

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The invention of seismometers & Seismographs 

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The invention of seismometers & Seismographs 

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Tsunami Warning System Stimulus Video | AU

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Inquisitive has everything you need to teach Science, History and Geography Years F - 6 and now adding English units F - 6 and Maths units F - 2.

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Tilly Smith's Story of Surviving a Tsunami

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Tilly Smith's Story of Surviving a Tsunami

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The Story of Tilly Smith Stimulus Video | AU

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Inquisitive has everything you need to teach Science, History and Geography Years F - 6 and now adding English units F - 6 and Maths units F - 2.

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Erta Ale in eastern Ethiopia. mbrand85

Ethiopia tends to conjure images of sprawling dusty deserts, bustling streets in Addis Ababa or the precipitous cliffs of the Simien Mountains - possibly with a distance runner bounding along in the background. Yet the country is also one of the most volcanically active on Earth, thanks to Africa's Great Rift Valley, which runs right through its heart.

Rifting is the geological process that rips tectonic plates apart, roughly at the speed your fingernails grow. In Ethiopia this has enabled magma to force its way to the surface, and there are over 60 known volcanoes. Many have undergone colossal eruptions in the past, leaving behind immense craters that pepper the rift floor. Some volcanoes are still active today. Visit them and you find bubbling mud ponds, hot springs and scores of steaming vents.

This steam has been used by locals for washing and bathing, but underlying this is a much bigger opportunity. The surface activity suggests extremely hot fluids deep below, perhaps up to 300°C-400°C. Drill down and it should be possible access this high temperature steam, which could drive large turbines and produce huge amounts of power. This matters greatly in a country where 77% of the population has no access to electricity, one of the lowest levels in Africa.

Geothermal power has recently become a serious proposition thanks to geophysical surveys suggesting that some volcanoes could yield a gigawatt of power. That's the equivalent of several million solar panels or 500 wind turbines from each. The total untapped resource is estimated to be in the region of 10GW.

Converting this energy into power would build on the geothermal pilot project that began some 20 years ago at Aluto volcano in the lakes region 200km south of Addis Ababa. Its infrastructure is currently being upgraded to increase production tenfold, from 7MW to 70MW. In sum, geothermal looks like a fantastic low-carbon renewable solution for Ethiopia that could form the backbone of the power sector and help lift people out of poverty.

Scratching the surface

The major problem is that, unlike more developed geothermal economies like Iceland, very little is known about Ethiopia's volcanoes. In almost all cases, we don't even know when the last eruption took place - a vital question since erupting volcanoes and large-scale power generation will not make happy bedfellows.

In recent years, the UK's Natural Environment Research Council (NERC) has been funding RiftVolc, a consortium of British and Ethiopian universities and geological surveys, to address some of these issues. This has focused on understanding the hazards and developing methods for exploring and monitoring the volcanoes so that they can be exploited safely and sustainably.

Teams of scientists have been out in the field for the past three years deploying monitoring equipment and making observations. Yet some of the most important breakthroughs have come through an entirely different route - through researchers analysing satellite images at their desks.

This has produced exciting findings at Aluto. Using a satellite radar technique, we discovered that the volcano's surface is inflating and deflating. The best analogy is breathing - we found sharp "inhalations" inflating the surface over a few months, followed by gradual "exhalations" which cause slow subsidence over many years. We're not exactly sure what is causing these ups and downs, but it is good evidence that magma, geothermal waters or gases are moving around in the depths some five km below the surface.

Taking the temperature

In our most recent paper, we used satellite thermal images to probe the emissions of Aluto's steam vents in more detail. We found that the locations where gases were escaping often coincided with known fault lines and fractures on the volcano.

When we monitored the temperature of these vents over several years, we were surprised to find that most were quite stable. Only a few vents on the eastern margin showed measurable temperature changes. And crucially, this was not happening in synchronicity with Aluto's ups and downs - we might have expected that surface temperatures would increase following a period of inflation, as hot fluids rise up from the belly of the volcano.

It was only when we delved into the rainfall records that we came up with an explanation: the vents that show variations appear to be changing as a delayed response to rainfall on the higher ground of the rift margin. Our conclusion was that the vents nearer the centre of the volcano were not perturbed by rainfall and thus represent a better sample of the hottest waters in the geothermal reservoir. This obviously makes a difference when it comes to planning where to drill wells and build power stations on the volcano, but there's a much wider significance.

This is one of the first times anyone has monitored a geothermal resource from space, and it demonstrates what can be achieved. Since the satellite data is freely available, it represents an inexpensive and risk-free way of assessing geothermal potential.

With similar volcanoes scattered across countries like Kenya, Tanzania and Uganda, the technique could allow us to discover and monitor new untapped geothermal resources in the Rift Valley as well as around the world. When you zoom back and look at the big picture, it is amazing what starts to come into view.

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How to turn a volcano into a power station - with a little help from satellites

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Ethiopia tends to conjure images of sprawling dusty deserts, bustling streets in Addis Ababa or the precipitous cliffs of the Simien Mountains - possibly with a distance runner bounding along in the background. Yet the country is also one of the most volcanically active on Earth, thanks to Africa's Great Rift Valley, which runs right through its heart.

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Does geothermal energy only work in areas of volcanic activity?

If you were to take a sample of the population in most major countries and asked them to visually describe a geothermal energy plant, they might paint you a picture similar to the large steaming power plants near active volcanoes. Or they'd point you to pictures of geothermal activity in Iceland or New Zealand. However, geothermal energy can be found in many parts of the world, not associated with volcanic activity.

The term geothermal energy refers to any heat derived from the ground, whether that's a few metres (shallow geothermal) or a few hundred kilometres (deep geothermal) below the surface. Let's understand a little more about each of these concepts.
Shallow geothermal energy
Shallow geothermal energy, or low-grade ground-source energy, comes from heat absorbed from the sun by the earth. Developing shallow geothermal energy normally requires a heat pump to help increase temperatures to levels we can use to heat buildings. One example of shallow geothermal energy in the UK is the reuse of the country's historical mine sites (that have long since been disused). Mines used to require constant draining of wastewater to avoid contamination of rivers and potable aquifers. This 'waste' water is warm and having absorbed heat from the surrounding rocks, is now ready for repurposing to warm buildings. It's estimated that ¼ of the UK's population lives above abandoned mines. These mines have the potential to generate 2.2 million GWh of heat which could keep approximately 18 million people warm and cosy with no associated greenhouse emissions.
Deep geothermal energy
Deep geothermal energy is defined by the UK government as sourced from more than 500m depth. The heat is generated partly from primordial heat left over from when the Earth was formed, and partly from heat generated from the normal decay of naturally occurring radioactive minerals. There are many forms of deep geothermal energy, some that produce water that is hot enough for heating and others that produce steam, which can be used to generate electricity and heat.

The UK has been using deep geothermal energy since the times of the Roman occupation, in areas such as Bath in Somerset where the water naturally flows to the surface at approximately 45oC. More recently (since 1986) heat and with the addition of biomass heating, electric power has also been produced in Southampton. This has helped to save 10,000 metric tonnes of CO2 emissions from the port and surrounding municipal buildings every year.

More excitingly, in 2020 steam was produced directly from deep well bores at the United Downs Industrial Estate, near Redruth in Cornwall. A power plant is currently being constructed that will generate 65 MW of electrical power, with hot water being used to supply heat to a rum distillery and the local community.

Geothermal energy is being explored across the UK and in many other parts of the world. As our understanding of the related/required geology and new technologies to extract heat evolve, the prospects for geothermal are definitely increasing.

If the upfront cost of geothermal energy is high, does that make it unfeasible?

To answer this question, let's begin by defining the risks clearly. In a geothermal energy project, before any plans for drilling wells or constructing pipelines are made and before a plant is built, analysis is first carried out to understand the potential of heat generated from specific locations. In other words, the theoretical heat potential and the flow rate that exists deep underground needs to be proven. In many cases, this will require a well, which is an expensive upfront cost.

Early risks will naturally be closely followed by early costs. For example, the US Department of Energy (UoE) estimates that the initial cost for the field and power plant could be around $2500 per kW installed. While that is not something to scoff at, it's important to remember that the return on that investment could be much faster than you might expect.

So where would the cost savings be? Carbon taxes would be the first and most obvious example associated with a new geothermal energy plant. Exploration costs could also be reduced by increasing the publicly available geological data, (although this often requires mandatory regulatory compliance). Access to old mine records or previously drilled wells would help to further reduce assessment costs, streamline the permitting process and regulatory compliance. With robust cost modelling, a geothermal project can be planned in such a way as to reduce upfront spend, mitigate and, in some cases minimise the risk of well exploration. Subsidies from governments, incentives that include risk insurance, shared costs of drilling between public and private sectors are just some of the other ways to mitigate initial capital risk.

Reusing existing infrastructure can further decrease both risks and costs. By repurposing existing heat, such as re-using disused mine waters (already produced to mitigate against potential water resource pollution) can be an effective way to heat spaces. A great example of this is the Seaham Garden Village in County Durham, UK.

The other return on investment is, of course, the benefits in supply. To put some numbers in perspective, typical coal power plants have average availability of 75% (i.e. producing energy more than 75% of the time) or thereabouts. In comparison, geothermal plants are closer to 90% and are available 24 hours a day, 365 days a year!

Are investors really interested in geothermal energy projects today?

If you were to turn the clock back even 20 years ago, investors might have been sceptical about setting aside capital and resources into geothermal projects. Geothermal energy at the time was seen as a niche, geographically limited energy source that could not be scaled easily and therefore only likely to produce low returns on investment.

However, public awareness of climate change and the requirement for a continuous renewable energy source, (especially for areas that are hard to decarbonise such as space heating for domestic housing), has created greater market awareness and reignited an interest in geothermal investment.

The scalability and profitability of geothermal projects is now being reassessed with the advance of hydrocarbon industry technology. Horizontal drilling or HPHT (High Pressure and High Temperature technology) is one such example, as it can be used to drill deeper, and access hotter geothermal fluids. This would make previously ignored locations, geothermally accessible and worthy of investment. Also, our geological understanding in several areas has increased, ironically brought on by the shale boom, a facet of the hydrocarbon industry that has been historically controversial. It may still hold some of the answers to support de-risking geothermal project investment.

There are other new technologies also being constantly developed, many of which are in advanced feasibility test stages, leading to increased investment from large multinational companies. Technologies such as:

Closed loop systems which allow the circulation of fluids with a higher heat absorption capacity rather than water, enabling the use of geothermal energy in areas previously considered as unfavourable.

Repurposing of heat as a valuable resource, something that has previously been seen as a waste product. This is particularly interesting when combined with heat pump technology which allows low temperature extracted fluids to be increased to temperatures that can comfortably heat homes and offices.

A great example of this and the potential scalability within the UK, is the repurposing of disused mine discharge waters as described earlier.
The takeaway message here is one of technology advances, new thinking and scalability, all factors that tick a lot of ESG requirements, leading to a more buoyant investor potential. The numbers speak for themselves. In 2020, global geothermal investments increased six-fold from the year before, exceeding $675 million.

How could one negotiate the regulatory nightmare of geothermal energy exploration?

Exploitation of our natural resources is generally heavily regulated, and rightly so. To protect people and environment these regulations must be strictly enforced. Many regulations and permits differ from country to country, and in many cases, between regions in a single country. This can make the process complex leading to confusion, slowing down project delivery and in some cases cancelling a project all together.

What is needed here is clearly a process built on deep expertise, that makes the complexities of individual regulatory requirements easier to manage. With a 40-year history of successful projects completed within the energy sector, across both the oil and gas industry as well as renewables, we are best-placed to have these regulatory conversations with the right stakeholders. Our commercial and technical expertise can be brought to the fore against a geothermal project's unique permitting and regulatory compliance objectives. We understand subsurface geology and the field development planning that would go into a geothermal energy lifecycle and how to negotiate with challenging stakeholders.

Could geothermal power plants take up a lot of area?

Geothermal energy has the smallest land footprint of any comparable energy source in the world based on land use per gigawatt hours, making it perfect for urban areas, where instant constant dispatchable heat or power is required. As with everything else, size is relative to their heat and electricity supply requirements.

Consider the following scenario, as described by the US Department of Energy (DoE). Let's assume you want to produce a single gigawatt hour (GWh) or one million kilowatts of energy for a single hour. A typical geothermal power plant would use the equivalent of 1,046 sq. km (404 sq.m) of land.
To produce the same GWh, wind energy would need 3,458 sq. km (3237 sq. m). A solar photovoltaic plant requires 8,384 sq. km (sq. m) while coal plants would use about 9,433 sq. km (3,642 sq. m).

What about the risk of earthquakes? Do they outweigh the benefits of geothermal energy?

One of the historic and oft-repeated challenges of geothermal energy is that it could trigger seismic events such as earthquakes. However, recent research by Caltech suggests that geothermal energy development could reduce stress and aftershocks and prevent earthquakes of a larger magnitude in the same area in the future.

Caltech's research is based upon the 7.1 magnitude earthquake that struck Ridgecrest, California, on 5 July 2019. The Coso geothermal field was located within 10km of the epicentre, yet, seismologists and researchers from Caltech noted that of the thousands of aftershocks recorded across the region, none were seen in the geothermal field. They concluded that the regional operations related to geothermal energy production over the last 30 years could have relieved the stress and lowered the risk of a more powerful earthquake.

Using a technique called synthetic aperture radar (SAR) interferometry, seismologists learnt that the Coso field had sunk by tens of centimetres since this technique was first deployed. This contraction could have relieved tensions underground. In other words, the smaller magnitude (approximately four on the Richter scale) tremors that could have been recorded by fluid injections may have prevented the region from experiencing larger aftershocks.

There is always some risk of earthquakes with the start of any geothermal activity and most modern developments employ a system of seismic monitoring to assess risk. However, the Caltech study is insightful. If we learn to suppress seismicity in a region over time, the risks of geothermal exploration warrant a second check. Further research in this area is both required and welcomed.

These are important questions and it's equally important that we tackle them head-on and carefully. Today, geothermal exploration is poised for a seismic shift both in how it's perceived as well as how it is project managed. The time for us to be taking it more seriously is well overdue, but there's no time like the present to begin to have the right conversations with the right stakeholders, and we would certainly be able to facilitate them.

RPS has a 40-year history of successful project delivery across the energy sector, in both oil and gas and renewables. Built on our deep commercial and technical expertise, we understand subsurface geology and field development planning and consenting/permitting required to successfully deliver a geothermal energy project.

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The challenges of geothermal energy | RPS Insights | RPS

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Let's take a deep dive and try and understand geothermal energy challenges and what's holding us back from tapping into this abundant source.

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Volcanic landscape on the Reykjanes Peninsula in Iceland.

Credit: Reykjanes Peninsula image via Shutterstock

It's not every day that scientists can study a volcano up close, but researchers investigating the feasibility of volcano-powered electricity successfully drilled into the core of one in Iceland.

Scientists studied the volcanic system at Reykjanes Peninsula in Iceland, which has been dormant for more than 700 years, according to a hazard assessment by Verkis Consulting Engineers for Invest in Inceland.

The depths of Reykjanes' geothermal field - an area with high heat flow - had never been explored, researchers with the Iceland Deep Drilling Project (IDDP) said in a statement. Beginning in August 2016, the IDDP spent 168 days drilling into the volcanic belly of Reykjanes. This well was completed on Jan. 25, reaching a record-breaking depth of nearly 3 miles (4.8 kilometers). [ The 11 Biggest Volcanic Eruptions in History]

At this depth, the hole does not enter the magma chamber but does penetrate the rock surrounding it, which the researchers measured to be about 800 degrees Fahrenheit (427 degrees Celsius).

Geothermal energy uses the heat trapped beneath the Earth's surface to generate electricity. Conventional geothermal energy utilizes steam from natural sources such as geysers, or by drawing water from the hot, high-pressue depths of the Earth. The hot vapors are then used to drive electric turbines.

In the case of volcanic geothermal energy, the heat comes from "supercritical water." The researchers explained that energy from so-called supercritical water is much higher than conventional geothermal steam. When molten rock and water meet, the extreme heat and pressure bring water to a "supercritical" state, where it is neither liquid nor gas. In this form, the water can carry more energy than normal steam, which could create up to 10 timesthe power output of other geothermal sources.

Research will continue through 2018 to explore how the volcano's thermal energy could be used, including as a form of alternative energy, according to IDDP scientists.

"If deep supercritical wells, here and elsewhere in the world, can produce more power than conventional geothermal wells, fewer wells would be needed to produce the same power output, leading to less environmental impact and improved economics," IDDP researchers said in the statement.

Geothermal energy is a major source of energy in Iceland, with about 25 percent of the country's electricity generated from tapping the Earth's heat, according to the National Energy Authority of Iceland. About 90 percent of Icelandic households are heated with geothermal energy.

In its 2016 power production report, the Geothermal Energy Association (GEA) found that only 6 to 7 percent of global geothermal power potential has been tapped. However, production is on the rise and the GEA predicts global geothermal energy production will more than double by 2030.

Original article on Live Science.

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Magma Power: Scientists Drill into Volcano to Harness its Energy

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It's not every day that scientists can study a volcano up close, but researchers investigating the feasibility of volcano-powered electricity successfully drilled into the core of one in Iceland. Scientists studied the volcanic system at Reykjanes Peninsula in Iceland, which has been dormant for more than 700 years, according to a hazard assessment by Verkis Consulting Engineers for Invest in Inceland.

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Behind the News is a fun, accessible way for upper primary and secondary students to learn about what's happening in the world around them.

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6 ways volcanoes benefit Earth, our environment

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It may come as a surprise that volcanic activity can positively impact the environment and people living in the region.

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Australian Floods - History, Timeline, Effects 

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Australian Floods - History, Timeline, Effects 

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Students use the geographical tool - Disaster Mapper - on the Australian Disaster Resilience Knowledge Hub to investigate recent floods in Australia. They identify the location and extent of each disaster and the impact of the disaster on the local community.

Students use the "Jigsaw" approach to group work to research one flood in Australia. Each expert group uses the websites provided to research their inquiry question. Students present their group's information in a graphic organiser of their choice - ladder, staircase, chain of events or flow chart.

The geographical tools integrated in this lesson include mapping, visual representation and spatial technologies.

The geographical concepts include place, space and interconnection.

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Students use the geographical tool - Disaster Mapper - on the Australian Disaster Resilience Knowledge Hub to investigate recent floods in Australia. They identify the location and extent of each

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Cyclone Tracy has been described as the most significant tropical cyclone in Australia's history and it changed how we viewed the threat of tropical cyclones to northern Australia.

Five days before Christmas 1974, satellite images showed evidence of a tropical depression in the Arafura Sea, 700 kilometres north-east of Darwin.

The following day the Tropical Cyclone Warning Centre in Darwin issued a warning that a cyclone had formed and gave it the name Tracy.

Quick facts

Tracy was reported as a category four cyclone.

It was small but intense, the radius of the galeforce winds was only 50km.

Made landfall just north of Fannie Bay at 3:30am on Christmas Day 1974 and passed directly over Darwin.

Wind gust of 217kph was recorded before anemometer at Darwin Airport failed. Maximum wind gusts have been estimated at up to 240kph.

Darwin received 250mm of rain in 12 hours.

Debris indicated a four-metre storm surge at Casuarina Beach.

Sixty-five people died - 49 in Darwin and 16 lost at sea.

At least 90 per cent of homes in Darwin were demolished or badly damaged.

Total damage bill came to around $800 million or nearly $4.5 billion in today's money.

More than 30,000 Darwin residents were evacuated after the cyclone, many never returned.

Sources include Bureau of Meteorology
At this stage Cyclone Tracy was moving south-west, but as it passed north-west of Bathurst Island on December 23 it slowed down and changed course.

It rounded Cape Fourcroy that night and began moving south-east, with Darwin directly in its path.

The first warning that Darwin was under threat came at 12:30pm on Christmas Eve when a top-priority flash cyclone warning was issued advising people that Cyclone Tracy was expected to make landfall early Christmas morning.

Despite 12 hours' warning of the cyclone's impending arrival, it fell largely on deaf ears.

Residents were complacent after a near-miss from Cyclone Selma a few weeks before and distracted by the festive season.

Indeed in the preceding decade the Bureau of Meteorology had identified 25 cyclones in Northern Territory waters but few had caused much damage.

As Kevin Murphy describes in his history of NT tropical cyclones Big Blow Up North: "The residents of [Darwin] could almost have been forgiven for thinking by now that they were invincible."

Small but intense

Severe Tropical Cyclone Tracy was a small but intense system at landfall.

The radius of the galeforce winds extended only 50 kilometres from the eye of the cyclone, making it one of the smallest tropical cyclones on record according to the US National Oceanic and Atmospheric Administration (NOAA).

Records show that prior to Tracy, at least six tropical cyclones had severely impacted Darwin.

The worst of these was in January 1897 when a "disastrous hurricane" nearly destroyed the settlement and 28 people died.

However unlike Tracy, it is thought this cyclone did not directly pass over Darwin.

And while Tracy was reported as a category four cyclone, some meteorologists today believe it may have been a category five shortly before it made landfall.

At midnight on Christmas Day wind gusts greater than 100 kilometres per hour began to be recorded.

The centre of the cyclone reached East Point at 3:15am and made landfall just north of Fannie Bay at 3:30am.

Tracy was so strong it bent a railway signal tower in half.

The city was devastated by the cyclone. At least 90 per cent of homes in Darwin were demolished or badly damaged. Forty-five vessels in the harbour were wrecked or damaged.

In addition to the 65 people who died, 145 were admitted to hospital with serious injuries.

Vegetation was damaged up to 80 kilometres away from the coast and Darwin felt eerily quiet due to the lack of insect and bird life.

Within a week after the cyclone hit more than 30,000 Darwin residents had been evacuated by air or road, more than two-thirds of the population at that time.

Cyclone Tracy remains one of Australia's greatest disasters.

As Murphy wrote 10 years after the cyclone: "The impact of Cyclone Tracy has reached far beyond the limits of Darwin itself. All along the tropical coasts of northern Australia and beyond a new cyclone awareness has emerged."

That legacy continues today.

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Cyclone Tracy is considered the most significant tropical cyclone in Australia's history and changed how we view the threat to northern Australia.

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In 1974, Territorians had to pitch in together on Christmas morning after raging Cyclone Tracy flattened 70 per cent of Darwin.

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A dry landscape and a dire season: we explain the current bushfire environment

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Our bushfire expert Andrew Sullivan delves beyond the smoke haze to explain the current crisis and the tough conditions ahead.

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It's not simple to estimate the eventual economic cost of Australia's 2019-20 megafires, partly because they are still underway and partly because it's hard to know the cost to attribute to deaths and the decimation of species and habitats.

But it's easy to get an idea of its significance - and the cost will be unprecedented.

The deadliest bushfires in the past 200 years took place in 1851, then 1939, then 1983, 2009, now 2019-20. The years between them are shrinking rapidly.

Only a remote grassfire in central Australia in 1974-75 rivalled them in terms of size, although not in terms of material burnt or loss of life.

The term "megafire" is a new one, defined in the early 2000s to help describe disturbing new wildfires emerging in the United States - massive blazes, usually above 400,000 hectares, often joining up, that create more than usual destruction to life and property.

Australia's current fires dwarf the US fires that inspired the term.

They are 25 times the size of Australia's deadliest bushfires, the 2009 Black Saturday fires in Victoria that directly killed 173 people, and are so large and intense that they create their own weather in which winds throw embers 30 kilometres or more ahead of the front and pyro-cumulus clouds produce dry lightning that ignites new fires.

The Black Saturday fires burnt 430,000 hectares. The current fires have killed fewer people but have so far burnt 10.7 million hectares - an area the size of South Korea, or Scotland and Wales combined.

We can offer a preliminary calculation of the mammoth cost of the ongoing bushfires crisis.
THERE ARE EASY-TO-MEASURE COSTS ...
The government has promised to put at least $2 billion into a National Bushfire Recovery Fund, which is roughly the size of the first estimate of the cost of the fires calculated by Terry Rawnsley of SGS Economics and Planning.

He put the cost at somewhere between $1.5 and $2.5 billion, using his firm's modelling of the cost of the NSW Tathra fires in March 2018 as a base.

It's the total of the lost income from farm production, tourism and the like.

It is possible to get an idea of wider costs using the findings of the 2009 Victorian Bushfires Royal Commission.

It came up with an estimate for tangible costs of $4.3 billion, which after inflation would be about $5 billion in today's dollars.
... AND HARDER-TO-MEASURE COSTS
Tangible costs are those easily measured including the cost of replacing things such as destroyed homes, contents and vehicles.

They also include the human lives lost, which were valued at $3.7 million per life (2009 dollars) in accordance with a Commonwealth standard.

The measure didn't include the effect of injuries and shortened lives due to smoke-related stroke and cardiovascular and lung diseases, or damage to species and habitats, the loss of livestock, grain and feed, crops, orchards and national and local parks.

Also excluded were "intangibles", among them the social costs of mental health problems and unemployment and increases in suicide, substance abuse, relationship breakdowns and domestic violence.

The cost of intangibles can peak years after a disaster and continue to take tolls for decades, if not generations.

One attempt to estimate the cost of intangibles was made by Deloitte Access Economics, in work for the Australian Business Roundtable for Disaster Resilience & Safer Communities.

Deloitte put the tangible costs of the Black Saturday fires at $3.1 billion in 2015 dollars and the intangible costs at more than that again: $3.9 billion, producing a total of A$7 billion, which would be $7.6 billion in today's dollars.
BLACK SATURDAY IS A STARING POINT
This season's megafires are, so far, less costly than the 2009 Victorian fires in terms of human life, roughly on par in terms of lost homes, and less costly for other structures.

But given that considerably more land has been burnt, we can expect other costs to eclipse those of Black Saturday.

As of today, 25 times as much land has been burnt.

Scaling up the royal commission's Black Saturday figures for the size of the fire and scaling them down for the fewer deaths and other things that shouldn't be scaled up produces an estimate of tangible costs of $103 billion in today's dollars.

The Deloitte Access Economics ratio of intangible to tangible costs suggests a total for both types of costs of $230 billion.

As it happens, the tangible costs estimate is close to an estimate of $100 billion prepared using different methods by University of Queensland economist John Quiggin.

The reality won't be clear for some time.

There are several weeks of fire season remaining, and we are yet to reach the usual peak season for Victoria, which is the first week of February.

What we can safely say, with weeks left to go, is that these fires are by far Australia's costliest natural disaster.
Paul Read is a Climate Criminologist and Senior Lecturer in the Faculty of Medicine at Monash University. Richard Denniss is an Adjunct Professor at the Crawford School of Public Policy at Australian National University This article originally appeared on The Conversation and was reproduced with permission

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The bushfires crisis will cost Australia $100 billion, experts say

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It's not simple to estimate the eventual economic cost of Australia's 2019-20 megafires, partly because they are still underway and partly because it's hard to know the cost to attribute to deaths and the decimation of species and habitats. But it's easy to get an idea of its significance - and the cost will be unprecedented.

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Satellite to detect bushfires within 1 minute 

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Satellite to detect bushfires within 1 minute 

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Imagine a system that could detect any bushfire in Australia within minutes of ignition so firefighters could tackle the blaze before it spreads.

Last week saw an important development on the road to this future: a Queensland-based company, Fireball, announced the first purpose-built satellite for fire detection in Australia.

Scheduled for launch a year from now, the satellite is the first of a planned constellation of 24 that will monitor Australia from low Earth orbit.

Once the full system, including ground-based cameras and aerial drones, is up and running, Fireball says it will be able to spot any fires within one minute of ignition.

That may sound like a bold claim, but it's consistent with the goals of other organisations working on similar technology.

Within five years, experts say, we could have a national system of automated bushfire surveillance.

And we'll need it, too. With climate change, the continent is drying out and the summers growing longer and hotter, and bushfires are predicted to become more frequent and intense.

Catastrophic bushfire seasons, like the 2019-20 Black Summer, will be inevitable.

According to Marta Yebra, director of the Australian National University (ANU) Bushfire Initiative, advancements in satellites, drones and AI will drive big changes in firefighting.

"I strongly believe this will radically change the way we fight fires in Australia," she said.

At the same time, the challenges to making it happen are daunting.

A national system to detect fires in one minute one would produce vast amounts of data and require unprecedented cooperation between the patchwork of authorities and organisations.

The system would amount to automated surveillance of millions of square kilometres, accurate down to a few square metres and working non-stop all year.

How do we detect fires currently?

Though firefighting services have been trying new methods for detecting fires, most bushfires are still reported through triple-0.

There's no reliable Australian data on the average time between ignition and detection (due to the difficulty of calculating ignition time), but a 2012 CSIRO experiment found an observer in a tower took about 30 minutes.

In remote places without observers, or at night, fires can burn for hours before they're reported.

Fanned by wind, a new fire can spread at astonishing speeds. A CSIRO study estimated this at 1,500 square metres every 10 minutes.

In effect, authorities sometimes don't know about a fire until it's too late to stop it, Dr Yebra said.

"Basically, most of the fires from the 2019-20 season were ignited by lightning in remote areas. At the moment, we are missing the small fires," she said.

These small fires grow into big ones. The 2019-20 Gospers Mountain mega-fire that ended up burning half a million hectares over a period of months was traced back to a single lightning bolt.

An ANU study last year attempted to model the economic cost of not detecting fires early over the coming years, when bushfires are expected to grow more frequent and intense.

It found detecting and responding to both large and small fires within 30 minutes could save over $8 billion in destroyed property and fire-fighting costs over the next 30 years.

Algorithm often quicker than triple-0

During the Black Summer, an algorithm developed by RMIT used photos from the Japanese weather satellite Himawari 8 photos to detect new fires.

The detection system turned out to be blindingly quick.

It took the system about 60 seconds to process the satellite photos and sound an alert, said Simon Jones, a professor at RMIT's Remote Sensing Research Group, who helped develop the algorithm.

However, the total detection time was longer than that, because Himawari 8 only takes one photo every 10 minutes and the data has to first travel through the Japanese meteorological service. Ultimately, there's a minimum half-hour delay built into the system.

Also, fires smaller than a few football ovals might not be detected because the resolution of the satellite photo is only about 500 metres per pixel.

Still, RMIT's algorithm was often quicker than the traditional ways of detecting fires.

A subsequent study found that 80 per cent of the system's reports of new "hot spots" arrived faster than the triple-0 or other kinds of incident reports.

As well as being quick, the system worked day and night.

"The key diagnostic is that triple-0 and [state observers] rely on someone being up there and being present," Professor Jones said.

"Whereas a satellite's Earth observation is day and night and everywhere."

Automated water gliders to the rescue

Although it may seem wildly ambitious, many experts say detecting fires within one minute anywhere in Australia is possible - and it could be done within five years to a decade.

ANU and Optus are developing a system of drone and ground-based cameras to automatically detect fires anywhere in south-eastern Australia.

They're aiming to get the detection time down to one minute by 2025.

On top of this, the proposed system would extinguish newly detected fires in five minutes.

To reach this goal, ANU have proposed a system of automated water-bombing gliders that can zero-in on their target (eg. a lightning-struck tree) and drop a payload of water. If they get to the target quickly enough, not too much water is needed to extinguish the fire.

A C-130 cargo plane flying safely high above the fires could hold 30 of these gliders, Dr Yebra said.

"They provide very rapid response and high accuracy and control over the spread of the water - day and night," she said.

Mining billionaire Andrew Forrest has also entered the fray. His Minderoo Foundation is working on an ambitious "Fire Shield" that, like ANU, would deploy automated firefighting machines to extinguish "dangerous blazes" anywhere on the continent within one hour.

Like ANU, its deadline is only a few years away, in 2025.

System already running in US

The Queensland-based company Fireball already has a system in the western states of the United States.

According to Fireball chief technology officer Tim Ball, this rapid detection time has changed the way fires were fought during the record-setting 2020 California fire season.

"In California, having this technology has changed the perspective of the fire services, because they fight fire much more aggressively," he said.

"They're not guessing at what's out there."

To detect fires from so far away, the Fireball system uses techniques developed to spot supernovae in distant galaxies.

In 1991, an astrophysicist at the University of California, Berkeley, Carl Pennypacker, witnessed a bushfire tear through his hillside neighbourhood.

He wondered if the type of satellite telescope he was using to detect bright spots a billion light years across the universe could be pointed back to Earth to detect a small fire.

The problem would be the same: filtering out background noise.

Twenty-two years later, in 2013, (after being part of Nobel Prize-winning research into the accelerating expansion of the universe), Professor Pennypacker and his team introduced the idea of using satellites and drones to snap images in the 3.9 micron band, a wavelength of light that fires emit but which is invisible to the human eye.

A computer would then spot the difference by subtracting recent photos from new ones of the same area.

Any new points of light in the 3.9 micron band would indicate a new ignition.

It worked. University of California patented the idea and Professor Pennypacker set up his own company, Fireball, that licenced the technology.

And then during the 2020 California fire season, Fireball's automated system detected 850 fires.

"Carl's idea was that we could see these tiny, tiny signals in a really noisy background at the edge of the cosmos," Dr Ball said.

"And if you're willing to make an aggressive attack on a tiny fire, it's not going to spread."

Can't rely solely on automated systems: NSW RFS

However, in contrast to Fireball's optimism, Australian fire services have expressed caution.

NSW RFS manager of predictive services, Laurence McCoy, said the service was in the "process of evaluating" using algorithms to automatically detect fires from satellite imagery, but he remained wary of too much automation.

"You can't rely on these systems solely," he said.

"You need people to interpret them."

And aside from interpretation, he said, you also need someone "on the ground" to check if there's a fire.

Of course, sending someone to check if the computer was right partly defeats the purpose of having automated detection.

Rural firefighting depends on volunteers, Mr McCoy said. Fire authorities need to be very certain they're needed before sounding the alarm.

"We want to have confidence in our monitoring," he said.

In a statement, QFES said it does not currently use satellite-based bushfire detection, "but is aware of companies developing these systems".

Fireball, meanwhile, is not waiting for the authorities to get onboard.

It's proceeding with a privatised model where the user pays for fire detection. It recently signed a deal with a Queensland plantation company.

"We are also looking into private companies, which have private firefighting forces," Fireball chief executive officer Christopher Tylor said.

Fireball estimated its full constellation of 24 satellites would be ready within five years.

As well as these, it's also looking into the possibility of launching a geostationary satellite, which would be much more expensive (Himawari 8 cost Japan about $1 billion to build and launch in 2014.)

In the meantime, it's also building a network of ground-camera-only fire surveillance. It estimated this would cost $12.30 per square kilometre, which it said worked out to an annual per capita cost of $13 in WA or 50 cents in Victoria.

"Noosa Shire has 55,000 people living there. The cost of the system, including the installation, would be under $1 per person living there per year," Mr Tylor said.

Will fire detection become privatised?

Fireball's satellite launch announcement raises the question: Will Australians living in wealthy areas one day have better fire detection than those elsewhere?

Dr Yebra said she's open to collaborating with Fireball on fire detection.

"Our hope is that at the ANU, we're able to coordinate the different initiatives," she said.

"I don't think a single company can cover the whole of Australia."

Australia doesn't have any of its own satellites for detecting bushfires. Instead, in an emergency, authorities rely on the goodwill of Japan, Korea and the European Union, who share data from their own expensive weather satellites.

What if that good will runs out in the middle of a catastrophic fire season?

This is one of the questions currently being asked at the parliamentary inquiry into Australia's space industry.

The NSW Government's submission to the inquiry notes that "the devastating 2019 bushfires demonstrated the potential advantages of Australian-managed and owned satellites".

And the Bureau of Meteorology's submission says: "Access to data from foreign-owned satellites depends on the capacity of foreign meteorological services and may not always be assured."

Dr Yebra said having Australian fire-detecting satellites was essential.

ANU plans to launch its own low Earth orbit satellite to map fuel loads and help determine bushfire risk, and is looking to raise $5 million to build the payload.

"I think the government needs to at least fund the research and development for the technology to be in a mature state," she said.

"And then it's the question of who is going to be maintaining the technology in the longer term."

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The bold plan to detect bushfires within one minute - and extinguish them before they spread

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Advancements in satellites, drones and AI are driving big changes in firefighting. Experts say a system that can detect bushfires anywhere in Australia within one minute of ignition is just around the corner.

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Inventions to stop the effects of flooding

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Inventions to stop the effects of flooding

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When it comes to flooding, there are essentially two ways to approach it: prevention or protection.

Preventing floods involves proper urban planning, proper sea-wall construction, and proper home-building practices. Even with all of the prevention that goes into modern infrastructure, there are many cases where prevention just doesn't cut it.
RELATED: GOOGLE TAKES ITS FLOOD PREDICTION TOOLS FOR INDIA TO THE NEXT LEVEL
In those cases, what we need is protection. This can involve equipment like sandbags, or building temporary flood barriers, and the likes. Let's examine seven different possible solutions to prevent and minimize the risk of flooding.

1. The rapid response water-gate

When flooding is imminent, you often need a barrier to protect yourself. Sandbags serve this task in many scenarios, but they may require a significant amount of preparation and set-up time, plus it's cumbersome to carry around. A device known as the water-gate can be a useful alternative. This is a rapidly deployable device made of a PVC material. It utilizes the pressure of oncoming water to stabilize itself. This essentially means that the floodwaters are used to build their own dam.
RELATED: VENICE MOSE FLOOD SYSTEM FINALLY COMES INTO OPERATION
Because the device leverages lightweight PVC and a design that leans on the water pressure to inflate it, the device itself is very compact and can be deployed by a single person in a matter of minutes to hours depending upon the size.

By surrounding a structure with the water-gate, a makeshift dam is created around the building. It's also completely reusable, so it's a great option for those living in a region at risk of flooding.

2. The Maeslant Storm Surge Barrier in the Netherlands

Netherlands' Deltaworks system is one of the most comprehensive flood protection systems in the entire world. This complex network of flood barrier infrastructure comes as a result of the country sitting almost entirely below sea level.

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7 Inventions and Ideas to Stop Flooding and Mitigate its Effects

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When it comes to flooding, there are essentially two ways to approach it: prevention or protection. Preventing floods involves proper urban planning, proper sea-wall construction, and proper home-building practices. Even with all of the prevention that goes into modern infrastructure, there are many cases where prevention just doesn't cut it.

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This article is published in collaboration with

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A new volcano alert system on New Zealand’s White Island could save lives

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In December, 21 people died when the volcano erupted with no warning. New technology could prevent that from happening again.

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Behind the News is a fun, accessible way for upper primary and secondary students to learn about what's happening in the world around them.

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Molly Wright: How every child can thrive by five

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"What if I was to tell you that a game of peek-a-boo could change the world?" asks seven-year-old Molly Wright, one of the youngest-ever TED speakers. Breaking down the research-backed ways parents and caregivers can support children's healthy brain development, Wright highlights the benefits of play on lifelong learning, behavior and well-being, sharing effective strategies to help all kids thrive by the age of five.

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What if there was no kindness in the world?

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What if there was no kindness in the world?

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A Hot Dog for Kindness | Paz Parel-Sewell | TEDxKids@ElCajon

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Stefan Al: Why isn't the Netherlands underwater?

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In January 1953, a tidal surge shook the North Sea. The titanic waves flooded the Dutch coastline, killing almost 2,000 people. 54 years later, a similar storm threatened the region. But this time, they were ready. This was thanks to a massive, interlocking system known as the Delta Works- the most sophisticated flood prevention project in the world.

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George T. Whitesides: The growing megafire crisis — and how to contain it

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Megafires, or fires that burn more than 100,000 acres, are becoming more frequent worldwide, wreaking havoc on landscapes and communities -- and fire experts say the problem is only going to get worse. George T. Whitesides is focused on fighting these devastating natural disasters through innovative technologies and intentional changes to how we build communities. He presents three emerging solutions to this blazing dilemma, calling for us to redefine our relationship with fire in order to build a more resilient and sustainable future.

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How google maps can help to assist after natural disasters

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How google maps can help to assist after natural disasters

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Lalitesh Katragadda: Making maps to fight disaster, build economies

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As of 2005, only 15 percent of the world was mapped. This slows the delivery of aid after a disaster -- and hides the economic potential of unused lands and unknown roads. In this short talk, Google's Lalitesh Katragadda demos Map Maker, a group map-making tool that people around the globe are using to map their world.

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George T. Whitesides: The growing megafire crisis — and how to contain it

# data[].attributes.attachment_link.description
Megafires, or fires that burn more than 100,000 acres, are becoming more frequent worldwide, wreaking havoc on landscapes and communities -- and fire experts say the problem is only going to get worse. George T. Whitesides is focused on fighting these devastating natural disasters through innovative technologies and intentional changes to how we build communities. He presents three emerging solutions to this blazing dilemma, calling for us to redefine our relationship with fire in order to build a more resilient and sustainable future.

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1816 The Year with no summer: Why do scientists want to block the sun 

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1816 The Year with no summer: Why do scientists want to block the sun 

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David Biello: 1816: The year with no summer

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In 1815, Mount Tambora erupted and its emissions spread across the globe, blotting out the sun for almost an entire year. This wreaked havoc on agriculture, leading to famines all across the Northern hemisphere. It was the year without summer- one of the darkest periods in human history.

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Jean-Baptiste P. Koehl: Iceland’s superpowered underground volcanoes | TED Talk

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While the weather in Iceland is often cold, wet, and windy, a nearly endless supply of heat bubbles away below the surface. In fact, almost every building in the country is heated by geothermal energy in a process with virtually no carbon emissions. So how exactly does this renewable energy work? Jean-Baptiste P. Koehl explores the two primary models for harnessing the planet’s natural heat. [Directed by Charlotte Arene, narrated by Addison Anderson, music by André Aires].

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The difficulty of predicting earthquakes

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The difficulty of predicting earthquakes

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Jean-Baptiste P. Koehl: Why are earthquakes so hard to predict?

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In 132 CE, Zhang Heng presented his latest invention: a large vase he claimed could tell them whenever an earthquake occurred for hundreds of miles. Today, we no longer rely on pots as warning systems, but earthquakes still offer challenges to those trying to track them.

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Volcanic ash is made of tiny fragments of jagged rock, minerals, and volcanic glass. Unlike the soft ash created by burning wood, volcanic ash is hard, abrasive, and does not dissolve in water. Generally, particles of volcanic ash are 2 millimeters (.08 inches) across or smaller. Coarse particles of volcanic ash look and feel like grains of sand, while very fine particles are powdery. Particles are sometimes called tephra-which actually refers to all solid material ejected by volcanoes. Ash is a product of explosive volcanic eruptions. When gases inside a volcano's magma chamber expand, they violently push molten rock (magma) up and out of the volcano. The force of these explosions shatters and propels the liquid rock into the air. In the air, magma cools and solidifies into volcanic rock and glass fragments. Eruptions can also shatter the solid rock of the magma chamber and volcanic mountain itself. These rock fragments can mix with the solidified lava fragments in the air and create an ash cloud. Wind can carry small volcanic ash particles great distances. Ash has been found thousands of kilometers away from an eruption site. The smaller the particle, the further the wind will carry it. The 2008 eruption of Chaitén in Chile produced an ash cloud that blew 1,000 kilometers (620 miles) across Patagonia to Argentina, reaching both the Atlantic and Pacific coasts. Volcanic ash deposits tend to be thicker and have larger particles closer to the eruption site. As distance from the volcano increases, the deposit tends to thin out. The 1994 double eruption of Vulcan and Tavurvur in Papua New Guinea covered the nearby city of Rabaul in a layer of ash 75 centimeters (about 2 feet) deep, while areas closer to the volcanoes were buried under 150-213 centimeters (5-7 feet) of ash. In addition to shooting volcanic ash into the atmosphere, an explosive eruption can create an avalanche of ash, volcanic gases, and rock, called a pyroclastic flow. These incredibly fast avalanches of volcanic debris can be impossible for humans to outrun. Pyroclastic flows are capable of razing buildings and uprooting trees. Volcanic Ash Impacts Plumes of volcanic ash can spread over large areas of sky, turning daylight into complete darkness and drastically reducing visibility. These enormous and menacing clouds are often accompanied by thunder and lightning. Volcanic lightning is a unique phenomenon and scientists continue to debate the way it works. Many scientists think that the sheer energy of a volcanic explosion charges its ash particles with electricity. Positively charged particles meet up with negatively charged particles, either in the cooler atmosphere or in the volcanic debris itself. Lightning bolts then occur as a means of balancing these charge distributions. Volcanic ash and gases can sometimes reach the stratosphere, the upper layer in Earth's atmosphere. This volcanic debris can reflect incoming solar radiation and absorb outgoing land radiation, leading to a cooling of the Earth's temperature. In extreme cases, these "volcanic winters" can affect weather patterns across the globe. The 1815 eruption of Mount Tambora, Indonesia, the largest eruption in recorded history, ejected an estimated 150 cubic kilometers (36 cubic miles) of debris into the air. The average global temperature cooled by as much as 3° Celsius (5.4° Fahrenheit), causing extreme weather around the world for a period of three years. As a result of Mount Tambora's volcanic ash, North America and Europe experienced the "Year Without a Summer" in 1816. This year was characterized by widespread crop failure, deadly famine, and disease. Airborne volcanic ash is especially dangerous to moving aircraft. The small, abrasive particles of rock and glass can melt inside an airplane engine and solidify on the turbine blades-causing the engine to stall. Air traffic controllers take special precautions when volcanic ash is present. The 2010 eruption of Eyjafjallajökull, Iceland, produced an ash cloud that forced the cancelation of roughly 100,000 flights and affected 7 million passengers, costing the aviation industry an estimated $2.6 billion. Volcanic ash can impact the infrastructure of entire communities and regions. Ash can enter and disrupt the functioning of machinery found in power supply, water supply, sewage treatment, and communication facilities. Heavy ash fall can also inhibit road and rail traffic and damage vehicles. When mixed with rainfall, volcanic ash turns into a heavy, cement-like sludge that is able to collapse roofs. In 1991, Mount Pinatubo erupted in the Philippines at the same time that a massive tropical storm wreaked havoc in the area. Heavy rains mixed with the ash fall, collapsing the roofs of houses, schools, businesses, and hospitals in three different provinces. Ash also poses a threat to ecosystems, including people and animals. Carbon dioxide and fluorine, gases that can be toxic to humans, can collect in volcanic ash. The resulting ash fall can lead to crop failure, animal death and deformity, and human illness. Ash's abrasive particles can scratch the surface of the skin and eyes, causing discomfort and inflammation. If inhaled, volcanic ash can cause breathing problems and damage the lungs. Inhaling large amounts of ash and volcanic gases can cause a person to suffocate. Suffocation is the most common cause of death from a volcano. Volcanic Ash Clean Up Volcanic ash is very difficult to clean up. Its tiny, dust-sized particles can enter into practically everything-from car engines, to office building air vents, to personal computers. It can severely erode anything that it contacts, often causing machinery to fail. When dry, ash can be blown by the wind, spreading into and polluting previously unaffected areas. Meanwhile, wet ash binds to surfaces like cement and removing it often means stripping away what is found underneath. Cleaning up volcanic ash is a costly and time-consuming procedure. Communities must make coordinated efforts to dispose of ash while ensuring the safety of their residents. The 1980 eruption of Mount St. Helens covered the city of Yakima, Washington, in tons of volcanic ash. Declaring a state of emergency, Yakima received donated maintenance equipment and workers, who were then dispatched throughout the city in a grid pattern. Citizens also helped with a block-by-block cleanup effort. Yakima removed 544,000 metric tons of ash and disposed of it in landfills and local fairgrounds. The city even filled in a wasteland to create a new city park. The process took seven around-the-clock days and cost the city $5.4 million, often cited as an efficient and cost-effective example of ash cleanup. Organizations such as the International Volcanic Health Hazard Network, the USGS Volcano Hazards Program, and the Cities and Volcanoes Commission create and disseminate information to the public about preparing for and cleaning up volcanic ash fall. Their guidelines are used throughout the world by city and town governments and by the citizens they serve.

Fast Fact

Andisol Andisol is a type of soil formed from volcanic ash. Andisols are generally very fertile, support extensive agricultural development, and exist mostly around the Ring of Fire.

Fast Fact

Flying High Scientists recently discovered that the eruption of Alaska's Mount Churchill roughly 1,200 years ago produced an ash fall that reached from Canada to Germany some 7000 kilometers (4350 miles) away. The discovery was especially surprising given that the volcano ejected a relatively small amount of ash of 50 cubic kilometers (12 cubic miles). As the ash spread, however, it transformed into microscopic shards called cryptotephra that had a unique compositional signature. Scientists were able to identify these distinct shards in Nova Scotia, Greenland, and across Northern Europe, suggesting that the cryptotephra was so light that it travelled easily along the high-altitude winds of the Northern Hemisphere.

Fast Fact

Pompeii Preserved One of the most famous explosive volcanic eruptions occurred in 79 CE, when Mount Vesuvius buried the Roman (now Italian) cities of Pompeii under 18 meters (60 feet) of ash. The ash buried the cities so completely that it preserved entire buildings, paintings, and artifacts. It also created very detailed molds around the bodies of people who were killed. Starting in the 18th century, archaeologists began excavating Pompeii. They discovered the hollow impressions left by bodies in the hardened ash and developed a way to inject them with plaster to create casts of the bodies. Today the excavated city and its gruesome models of dead and dying people and animals are popular tourist attractions.

Fast Fact

Smoke Signal
When Mount St. Helens, in the U.S. state of Washington, erupted in 1980, a column of ash from the volcano rose 19 kilometers (12 miles) into the air.

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Human and Environmental Impacts of Volcanic Ash

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Volcanic ash is made of tiny fragments of jagged rock, minerals, and volcanic glass. Unlike the soft ash created by burning wood, volcanic ash is hard, abrasive, and does not dissolve in water. Generally, particles of volcanic ash are 2 millimeters (.08 inches) across or smaller.

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Volcanic ash may have a bigger impact on the climate than we thought

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When volcanos erupt, these geologic monsters produce tremendous clouds of ash and dust—plumes that can blacken the sky, shut down air traffic and reach heights of roughly 25 miles above Earth’s surface.

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Earth Science, Geology, Geography

Image

Photograph by Robert S. Patton

Volcanic ash is a mixture of rock, mineral, and glass particles expelled from a volcano during a volcanic eruption. The particles are very small-less than two millimeters in diameter. They tend to be pitted and full of holes, which gives them a low density. Along with water vapor and other hot gases, volcanic ash is part of the dark ash column that rises above a volcano when it erupts.

Due to their tiny size and low density, the particles that make up volcanic ash can travel long distances, carried by winds. When an ash column is moved about by wind, it is called an ash plume. Eventually the ash in the sky falls to the ground. It may create a thick layer of dust-like material on surfaces for miles around the original eruption.

Unlike the ash produced by burning wood and other organic materials, volcanic ash can be dangerous. Its particles are very hard and usually have jagged edges. As a result, it can cause eye, nose, and lung irritation, as well as breathing problems. While in the air, ash can cause problems for jet engines, forcing airlines to cancel flights through the affected area. An ashfall that leaves a thick layer of ash may cause roofs to collapse, clog gutters, and interfere with air conditioning units. Animals in an area coated by volcanic ash may have difficulty finding food, as the plants in the region may be covered in ash. Ash can also contaminate water supplies.

Director

Tyson Brown, National Geographic Society

Author

National Geographic Society

Production Managers

Gina Borgia, National Geographic Society

Jeanna Sullivan, National Geographic Society

Program Specialists

Sarah Appleton, National Geographic Society, National Geographic Society

Margot Willis, National Geographic Society

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Volcanic ash is a mixture of rock, mineral, and glass particles expelled from a volcano during a volcanic eruption.

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Yearly, the National Earthquake Information Center locates more than 20,000 earthquakes around the globe and approximately 55 earthquakes every day; in 2021, for example, around 2,200 earthquakes with a magnitude above 5.0 occurred. This makes earthquakes one of the most regularly occurring natural hazards with a huge impact on society, with economic, social, and environmental consequences.