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The lakes, forests, mists and snow of the Kola Peninsula, deep in the Arctic Circle, can make this corner of Russia seem like a scene from a fairy tale. Yet amidst the natural beauty stand the ruins of an abandoned Soviet scientific research station. In the middle of the crumbling building is a heavy, rusty metal cap embedded in the concrete floor, secured by a ring of thick and equally rusty metal bolts.

According to some, this is the entrance to hell.

This is the Kola Superdeep Borehole, the deepest manmade hole on Earth and deepest artificial point on Earth. The 40,230ft-deep (12.2km) construction is so deep that locals swear you can hear the screams of souls tortured in hell. It took the Soviets almost 20 years to drill this far, but the drill bit was still only about one-third of the way through the crust to the Earth's mantle when the project came grinding to a halt in the chaos of post-Soviet Russia.

The Soviets' superdeep borehole isn't alone. During the Cold War, there was a race by the superpowers to drill as deep as possible into the Earth's crust - and even to reach the mantle of the planet itself.

Now the Japanese want to have a go.
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"It was in the time of the Iron Curtain when the drilling was started," says Uli Harms of the International Continental Scientific Drilling Program, who as a young scientist worked on the German rival to the Kola borehole. "And there was certainly competition between us. One of the main motivations was that the Russians were simply not really open with their data.

"When the Russians started to drill they claimed they had found free water - and that was simply not believed by most scientists. There used to be common understanding among Western scientists that the crust was so dense 5km down that water could not permeate through it."

"The ultimate goal of the [new] project is to get actual living samples of the mantle as it exists right now," says Sean Toczko, programme manager for the Japan Agency for Marine-Earth Science. "In places like Oman you can find mantle close to the surface, but that's mantle as it was millions of years ago.

"It's the difference between having a live dinosaur and a fossilised dinosaur bone."

If the Earth is like an onion, then the crust is like the thin skin of the planet. It is only 25 (40km) miles thick. Beyond this, is the 1,800-mile deep mantle and beyond that, right at the center of the Earth, is the core.

Like the space race, the race to the explore this unknown "deep frontier" was a demonstration of engineering prowess, cutting-edge technology and the "right stuff". The scientists were going where no human had gone before. The rock samples these super-deep boreholes could supply were potentially as important for science as anything Nasa brought back from the moon. The only difference was that this time the Americans didn't win the race. In fact, no-one really did. ( Read about how a switch saved the race to the Moon from disaster.)

The US had fired up the first drill in the race to explore the deep frontier. In the late 1950s, the wonderfully named American Miscellaneous Society came up with the first serious plan to drill down to the mantle. The society-turned-drinking-club was an informal group made up of the leading lights of the US scientific community. Their crack at drilling through the Earth's crust to the mantle was called Project Mohole, named after the Mohorovičić discontinuity, which separates the crust from the mantle.

Rather than drill a very, very deep hole, the US expedition - observed by novelist John Steinbeck - decided to take a short cut through the Pacific Ocean floor off Guadalupe, Mexico.

The advantage of drilling through the ocean floor is that the Earth's crust is thinner there; the disadvantage is that the thinnest areas of crust is usually where the ocean is at its deepest.

The Soviets started to drill in the Arctic Circle in 1970. And finally, in 1990, the German Continental Deep Drilling Program (KTB) began in Bavaria - and eventually drilled down to 5.6 miles (9km).

As with the mission to the Moon, the problem was that the technologies needed for the success of these expeditions had to be invented from scratch.

When in 1961 Project Mohole began to drill into the seabed, deep-sea drilling for oil and gas was still far off. No one had yet invented now essential technologies such as dynamic positioning, which allows a drill ship to stay in its position over the well. Instead, the engineers had to improvise. They installed a system of propellers along the sides of their drill ship to keep it steady over the hole.

One of the biggest challenges the German engineers faced was the need to drill a hole that is as vertical as possible. The solution they came up with is now a standard technology in the oil and gas fields of the world.

"What was clear for the experience of the Russians was that you have to drill as vertical as possible because otherwise you increase torque on the drills and kinks in the hole," says Uli Harms. "The solution was to develop vertical drilling systems. These are now an industry standard, but they were originally developed for KTB - and they worked until 7.5kms (4.7 miles). Then for the last 1.5-2km (.9 to 1.25 miles) the hole was off the vertical line for almost 200m.

"We tried to utilise some of the Russian techniques in the early 90s or late 80s when Russia became more open and willing to cooperate with the West," he adds. "Unfortunately, it was not possible to get the equipment in time."

However, all of these expeditions ended in a degree of frustration. There were false start and blockages. Then there were the high temperatures their machinery encountered that deep underground, the cost and the politics - all of which put paid to the dreams of the scientists to drill deeper, and break the record for the deepest hole.

Two years before Neil Armstrong walked on the moon, US Congress cancelled the funding for Project Mohole when costs began to spiral out of control. The few metres of basalt that they were able to bring up worked out at a cost of roughly $40m (£31m) in today's money.

Then it was the turn of the Kola Superdeep Borehole. Drilling was stopped in 1992, when the temperature reached 180C (356F). This was twice what was expected at that depth and drilling deeper was no longer possible. Following the collapse of the Soviet Union there was no money to fund such projects - and three years later the whole facility was closed down. Now the desolate site is a destination for adventurous tourists.

The German borehole has been spared the fate of the others. The huge drill rig is still there - and a tourist attraction today - but today the crane just lowers instruments for measurement. The site has become in effect an observatory of the planet - or even an art gallery.

When Dutch artist Lotte Geevan lowered her microphone protected by a thermal shield down the German borehole, it picked up a deep rumbling sound that scientists couldn't explain, a rumbling that made her "feel very small; it was the first time in my life this big ball we live on came to life, and it sounds haunting," she says. "Some people thought it did sound like hell. Others thought they could hear the planet breathe."

"The plan was there to drill deeper than the Soviets," says Harms, "but we hadn't even reached our allowed phase of 10km (6.25 miles) in the time we had. Then where we were drilling was just much hotter than where the Russians were. It was pretty clear that it was going to be much more difficult for us to go any deeper.

"By then it was also the early 90s in Germany and there was no good argument to raise additional funding to go any deeper because the German unification was costing such a lot of money."

It is hard not to shake off the feeling that the race to the Earth's mantle is an updated version of the famous novel Journey to the Centre of the Earth. While the scientists don't expect to find a hidden cavern full of dinosaurs, they do describe their projects as "expeditions".

"We thought of it as an expedition because it really took some time in terms of preparation and execution," says Harms, "and because you're really going into no-man's land, where no-one has been before, and that is really unusual today.

"You always find down there something that really surprises you, and especially if you go down into an area that is very deep in the crust.

"And if we talk about KTB or the Kola Superdeep, then the theories that were behind the goals of the project were 30-40 years old by the time drilling started."

"The thing about these missions is that they are like planetary exploration," says Damon Teagle, professor of geochemistry in the School of Ocean and Earth Science, National Oceanography Centre Southampton at the University of Southampton, who has been heavily involved in the new Japanese-led project. "They are pure science undertakings and you never know quite know what you are going to find.

"At Hole 1256 [a hole drilled by the Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP)], we were the first get to see intact ocean crust. No one had got to it before. It was really exciting. There are always surprises."

Today, "M2M-MoHole to Mantle" is one of the most important projects of the International Ocean Discovery Program (IODP). As with the original Project Mohole, the scientists are planning to drill through the seabed where the crust is only about 6km (3.75 miles) deep. The goal of the $1bn (£775m) ultradeep drilling project is to recover the in-situ mantle rocks for the first time in the human history.

"To do this would be an amazing undertaking and require a huge commitment from Japan," says Teagle, who is involved in the project.

Despite the importance of the project, the huge drilling ship the Chikyū was built almost 20 years ago with this project in mind. The Chikyū uses a GPS system and six adjustable computer-controlled jets that can alter the position of the huge ship by as little as 50cm (20in).

"The idea is that this ship would pick up the torch and continue the work started by the original Mohole project 50 years ago," says Sean Toczko, programme manager for the Japan Agency for Marine-Earth Science. "Superdeep boreholes have made a lot of progress in telling us about the thick continental crust. What we are trying to do is find out more about the Crust-Mantle boundary.

"The main sticking point is that there are three main candidate sites. One of those is off Costa Rica, one off Baha, and one off Hawaii."

Each of the sites involves a compromise between the depth of the ocean, distance from the drilling site and the need for a base on the shore that can support a billion-dollar, 24-hours-a-day operation at sea. "The infrastructure can be built up, but that takes time and money," adds Toczko.

"In the end, it really is a cost issue," says Harms. "These expeditions are extremely expensive - and therefore they are difficult to repeat. They can cost hundreds of millions of euros - and only a small percentage will actually be for the earth sciences, the rest will be for technological development, and of course, operations.

"We need inspiring politicians to talk up the value of these expeditions."

--

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The lakes, forests, mists and snow of the Kola Peninsula, deep in the Arctic Circle, can make this corner of Russia seem like a scene from a fairy tale. Yet amidst the natural beauty stand the ruins of an abandoned Soviet scientific research station.

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Which country's food is produced the most sustainable?

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Which country's food is produced the most sustainable?

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by twistedsifter

The skies have always been a constant source of fascination for humans. One common mass that everyone on the planet has seen in one form or another are clouds. They can come in all sizes, shapes, and colours; and their distinct formations have been studied by meteorologists for centuries. Below you will find a collection of 15 fascinating and incredible cloud formations. Enjoy!

Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization. The name translates approximately as roughened or agitated waves

The clouds are most closely related to undulatus clouds.[3] Although they appear dark and storm-like, they tend to dissipate without a storm forming. The ominous-looking clouds have been particularly common in the Plains states of the United States, often during the morning or midday hours following convective thunderstorm activity. [Source: Wikipedia]

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Roll Cloud, Las Olas Beach, Uruguay | Photograph by Daniela Mirner Eberl The skies have always been a constant source of fascination for humans. One common mass that everyone on the p...

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This incredible occurrence can be occasionally seen in the night sky over Britain.

The northern lights (also known as aurora borealis) appear as large areas of colour including pale green, pink, shades of red, yellow, blue and violet in the direction due north. During a weak aurora, the colours are very faint and spread out whereas an intense aurora features greater numbers of and brighter colours which can be seen higher in the sky with a distinct arc. The northern lights are best seen in darkness, away from any light pollution. The lights generally extend from 50 miles to as high as 400 miles above the Earth's surface.

What causes the northern lights?

The northern lights occur as a consequence of solar activity and result from collisions of charged particles in the solar wind colliding with molecules in the Earth's upper atmosphere.

Solar winds are charged particles that stream away from the Sun at speeds of around 1 million miles per hour. When the magnetic polarity of the solar wind is opposite to the Earth's magnetic field, the two magnetic fields combine allowing these energetic particles to flow into the Earth's magnetic north and south poles. Auroras usually occur in a band called the annulus (a ring about 1,865 miles across) centred on the magnetic pole. The arrival of a Coronal Mass Ejections (CME) from the Sun can cause the annulus to expand, bringing the aurora to lower latitudes. It is under these circumstances that the lights can be seen in the UK.

Depending on which gas molecules are hit and where they are in the atmosphere, different amounts of energy are released as different wavelengths of light. Oxygen gives off green light when it is hit 60 miles above the Earth, whilst at 100-200 miles rare, all-red auroras are produced. Nitrogen causes the sky to glow blue yet when higher in the atmosphere the glow has a purple hue.

Which weather conditions are best to view the northern lights?

The best conditions to view the lights are when the sky is dark and clear of any clouds. Cloud cover ultimately blocks the view of the light. Ideally, the lights will be best viewed away from any light pollution, in remote areas, facing the northern horizon - north facing coasts produce some of the best viewing locations. The northern lights are most active during t he Equinox and Solstice in March/April and September/October.

Where can you see the northern lights in the UK?

Predominantly the northern lights are best witnessed in Scotland, North England, North Wales and Northern Ireland. However under severe space weather conditions, the lights can be seen throughout the UK.

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This incredible occurrence can be occasionally seen in the night sky over Britain. The northern lights (also known as aurora borealis) appear as large areas of colour including pale green, pink, shades of red, yellow, blue and violet in the direction due north.

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Unless you are a professional geologist or engineer, it's unlikely that you give much thought to the science of geology and how it affects your day-to-day activities. However, the study of the Earth's composition, processes, and mineral makeup is integral to many of the daily activities, products and tools that we take for granted.

Let's take a look at the role geology plays in our everyday lives .

Many different types of energy are impacted by Geology. Fossil fuels have been created over the course of hundreds and thousands or even millions of years as the product of geological forces. Decomposing organic matter trapped beneath sediment and rock is transformed into carbon-rich oil and gas over many millennia.

We then use this fuel to heat our homes, power our vehicles, and much more. The conveniences and amenities of modern life would be impossible without fossil fuels, and without geologists to help discover and extract these sources of energy.

Geologists also play an important role in the advancement of alternative energies by studying and searching for minerals to be used in batteries and solar panels, finding and harnessing geothermal, tidal and hydroelectric power, and more.

Everything you consume originates from the soil. Even meat products derived from animals such as cows, pigs, chicken and fish have to be fed from plants and other organisms that are in turn fed by minerals that come from the Earth.

Therefore, the geological studies of soil erosion and soil health, plus identifying, predicting and accessing sources of water for irrigation are all integral to our ability to feed ourselves now and into the future. Geologists also help find sources of minerals that are used to fertilize our agricultural products and increase outputs.

Nothing is more imperative to our ability to survive than the availability of drinkable water. Our water comes from lakes, rivers and underground aquifers that can easily become contaminated if not monitored and protected. Geologists perform essential work mapping out the configuration of bodies of water both above and underground and identifying potential sources of pollution and contamination that would affect our ability to drink it, swim in it and bathe with it.

Our ability to survive natural disasters such as earthquakes, landslides, floods and volcanic eruptions is enormously influenced by our ability to predict their occurrence as much as possible, as well as plan and engineer structures to mitigate their impact.

Geologists play an integral role in studying seismic activity, weather patterns and tectonic movements to assist in preparing for potential adverse events. They also assist in engineering structures to withstand flooding, earthquakes and more.

Any time you drive anywhere, you can also thank a geologist for ensuring that the bridges and roads have been safely designed with the stability of the underlying sediments and rock in mind. The next time you are in a skyscraper, you can also marvel at the geologic engineering that ensured such a structure had a properly stable foundation to support itself.

Public domain image courtesy of the .

I'll bet you didn't think dental health had any relation to geology. But the main ingredient in toothpaste (and water) that keeps your tooth enamel healthy and strong - fluoride - is a mineral found in rock. Who do you think searches for and finds that mineral? You guessed it - geologists.

Minerals are also added to some foods and of course vitamins, which many people take to boost their health. These are all substances that geologists may be charged with finding.

These days, precious minerals like gold, silver and platinum are used for so much more than jewelry and coins. Our modern world has an insatiable appetite for cell phones, tablets, laptops, cameras, music players and other electronics. All these tools require a variety of metals and minerals like lithium, copper, silicon, zinc, aluminum and many more to perform the amazing functions we take for granted.

These applications are really just the tip of the iceberg. The study of geology truly touches our lives every single day whether we are aware of it or not. So be sure to thank a geologist today!

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Unless you are a professional geologist or engineer, it's unlikely that you give much thought to the science of geology and how it affects your day-to-day activities. However, the study of the Earth's composition, processes, and mineral makeup is integral to many of the daily activities, products and tools that we take for granted.

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Ecosystems are declining rapidly because of human actions. But there is still time to save them

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Ecosystems are declining rapidly because of human actions. But there is still time to save them

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Humans are causing life on Earth to vanish

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We are gambling with the only world we have, say researchers.

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Hunter-gatherer societies and early farming were transforming Earth thousands of years ago, long before greenhouse gas emissions and other effects often attributed to the middle of the 20th century.

Earlier this year, scientists suggested that the Anthropoecene, a geologic epoch defined by ways humans have altered Earth, began in 1950.

But the very definition of human activity and its effects is subject to debate by scientists. Some have even suggested the Industrial Revolution as the beginning of significant human impact on the environment and planet.

But a new global study has pooled together evidence to show that humans significantly altered land, contributing to Earth's transformation, as long as 10,000 years ago. Farming especially impacted the land by 3,000 years ago. The study published Thursday in the journal Science.

More than 250 archaeologists across the globe analyzed land use from 10,000 years ago to after the Industrial Revolution in 1850. Using this data, they were able to create a map as part of the ArchaeoGLOBE project. The project uses online surveys to collect information from experts in 146 locations around the world on the shift of land usage over time.

The definition of land use can include everything from hunting and gathering activities to farming and allowing animals to graze.

Foraging, also called hunting and gathering, was once a common practice around the world. By 3,000 years ago, it was fading as pastoralism, or raising livestock, spread from Southwest Asia to Eurasia and North Africa around 4,000 years ago. Farming also spread between 3,000 and 6,000 years ago. But in some parts of the world, farming and foraging happened simultaneously to complement each other.

"About 12,000 years ago, humans were mainly foraging, meaning they didn't interact with their environments as intensively as farmers generally do," said Gary Feinman, one of the study authors and MacArthur Curator of Anthropology at the Field Museum in Chicago. "And now we see that 3,000 years ago, we have people doing really invasive farming in many parts of the globe."

In order to farm the land, forests were cleared for planting. Domesticating and herding animals also required land clearing. In the case of these activities, it wasn't the pace that changed the land, but the widespread activity, the researchers said.

"We saw an accelerated trajectory of environmental impact," said Ryan Williams, study co-author and associate curator and head of anthropology at the Field Museum. "While the rate at which the environment is currently changing is much more drastic, we see the effects that human impacts had on the Earth thousands of years ago."

Understanding the ways that more ancient civilizations changed the planet also allows researchers to search for any solutions that were also created to prevent water scarcity or the negative impact of clearing forests.

"While modern rates and scales of anthropogenic global change are far greater than those of the deep past, the long-term cumulative changes wrought by early food producers are greater than many realize," said Andrea Kay, study author at of the Max Planck Institute for the Science of Human History and The University of Queensland, a lead author on the study. "Even small-scale or shifting agriculture can cause global change when considered at large scales and over long time-periods," she adds.

The crowd-sourced data allowed the researchers to assess and understand regions that haven't been studied as thoroughly in the past. The authors of the study hope that this is just the beginning of studying regions that have been closed off due to transportation issues, war, harsh environments or other factors.

"What really got me here was not so much the results, although I think that the results provide a foundation to support what many archeologists suspected," says Feinman. "But I think the most innovative aspect of this was the whole research design. To gather information from 250 scholars and to make sure that the whole world was covered, that's really something."

Changes to the climate and environment today happen at a quicker pace with more widespread effects. Research like this can lay the foundation for understanding how it happens and ways to mitigate the harmful changes.

"There's such a focus on how the present is different from the past in contemporary science. I think this study provides a check, a counter-weight to that, by showing that yes, there have been more accelerated changes in land use recently, but humans have been doing this for a long time. And the patterns start 3,000 years ago," says Feinman. "It shows that the problems we face today are very deep-rooted, and they are going to take more than simple solutions to solve. They cannot be ignored."

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Humans have been impacting Earth for thousands of years, study says | CNN

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Hunter-gatherer societies and early farming were transforming Earth thousands of years ago, long before greenhouse gas emissions and other effects often attributed to the middle of the 20th century. Earlier this year, scientists suggested that the Anthropoecene, a geologic epoch defined by ways humans have altered Earth, began in 1950.

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Full article: https://www.amnh.org/shelf-life/six-extinctions

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Six Extinctions In Six Minutes - Shelf Life #12

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Just like animals, volcanoes go through a life cycle of birth, growth, decline and finally death; they become extinct. In this installment, we will examine such a cycle of a fictitious volcanic complex and introduce another bucketful of terminology to the reader.

In the previous installment, we said that there were two main sources of volcanism, tectonic driven or hotspot driven. In order to simplify things, we will examine the life cycle of an Arc Volcano, one where the deep source of magma is the re-melting of a subducted continental slab. Some tens of millions of years ago, two continental plates collided and one, usually the "heavier" one, was subducted. A few million years ago, the edge of the slab had reached a depth of at least 50 km where it began to melt, dissolving the minerals into their constituent molecules and forming a glob of magma that began to rise through the semi-crystalline Upper Mantle or Astenosphere.

When it encountered the lower edge of the overlying continental plate, two things happened. The first was that it began to lift the overlying plate, inducing stresses in it that made it fracture. These small and very deep earthquakes as the plate began to fracture, together with the uplift were the first signs of a new area of volcanism. As more and more magma from the glob made its way upwards, the uplift increased. There were more fractures and fissures through which the juvenile magma could begin to make its way through, towards the surface.

The second was that being in excess of 1,400°C, the juvenile magma began to melt the overlying plate, assimilating a tiny portion of its material. Finally it reached a point at about 10 km depth where the overlying rock was no longer slightly ductile but hard. Here the magma began to collect in a body that was to become the future volcano's deep magma chamber. As it collected over tens of thousands of years, about 10 million cubic metres or 0.01 cubic km of it, with every new spurt or magmatic intrusion, it pushed the overlying rock upwards and that below downwards. Thus we must always remember when we read about uplift due to magmatic intrusion that the actual size of the intrusion is always twice that of the measured uplift!

Finally, enough juvenile magma had collected for it to cause such stress to the overlying rock that it too began to crack accompanied by great swarms of earthquake, tens of thousands of them. Then at about 5 km depth, the magmatic dike extending down to the deep magma chamber, stalled. Again, magma began to collect in a body, this time much smaller. But as time went on, it began to enlarge through re-melting of the surrounding bedrock and the addition of more magma from further intrusions. Also, it began to cool towards a point where minerals started to form. The magma began to evolve. Had no more magma been intruded from the mantle, over the next tens to hundreds of thousands of years, the intruded magma of the cryptodome would have cooled, mineralised and formed a pluton. This process is referred to as Plutonic mineralisation.

As the millennia passed, the cryptodome that was destined to become the volcano's upper magma chamber enlarged and heated more and more of the surrounding bedrock, making it ductile, until the remaining, brittle crust could no longer withstand the pressures from below. It began to fail and accompanied by another huge swarm of earthquakes, the now slightly evolved, but still mainly basaltic magma made its way to the surface in just a few days or weeks. For the very first time, the volcano erupted.

Because there had been so much magma collected before the pressure and stress induced made the overlying rock yield, the initial eruption was large and lasted a long time. With repose times between subsequent eruptions being measured in tens to maybe hundreds of years, the initial eruption phase lasted several thousand years, until the pressure difference built up from the point in time where the juvenile magma first began to form and collect in the deep magma reservoir had reached an equilibrium. Because the magma was basaltic, it flowed out across the overlying land to for a vast shield covering many hundreds of square kilometres with a few hundred cubic kilometres of magma that once it had erupted is referred to as lava, which solidified as blocky, glassy dark rocks of basaltic obsidian.

In its first incarnation, our volcano was a Shield volcano. While it may have covered an area roughly 15 km in radius, some 700 square kilometres, with in excess of 200 cubic kilometres of lava, because of the "runny" nature of basalt, the average inclination was only little more than a couple of degrees and the peak rose no more than 650 metres above the surrounding landscape, what is referred to as a mountain's prominence.

It now entered a long period of dormancy, occasionally broken by additional small eruptions of no more than a few hundredths of a cubic kilometre at a time. Also, because of the magma reservoirs being depleted with each further eruption, there was some collapse of the central parts which led to an enlargement of the summit crater to a diameter of a few kilometres. This caused the shield volcano to lose height until its prominence was no more than 575 metres. Because of its size and low gradient, you could stand on it and not know which direction was up and which was down. Indeed, if not seen from a great distance, it would be hard to know it was even there once vegetation had begun to cover it.

Then just over half a million years ago, a new glob of juvenile or primitive magma from the melting, subducted continental slab began to arrive. Again, magma began to collect in the now evolved magmas of the deep magma chamber. The old magma was remobilised and assimilated each subsequent pulse of juvenile magma from the mantle. The resulting magma mix was still basaltic in composition, but leaned towards basaltic-andesitic. This process was repeated when magma from the deep magma chamber made its way to the upper magma chamber, but because this was smaller, fractionation and mineralisation had progressed much further. Here, the resulting mix was basaltic-andesitic to andesitic. It was also rich in volcanic gasses, water, both from the original magmatic intrusions and from water contained in the bedrock that had made its way from the surface over uncounted millennia. The resulting mix was explosive.

Again accompanied by great earthquake swarms, not so great in number perhaps, but greater in size due the much higher pressures involved this time, the overlying structure yielded, opening a path to the surface a few kilometres from the original crater. The first, mainly andesitic eruption was explosive and sent a sub-Plinian column of ash 14 km into the sky. As the column collapsed, pyroclastic flows swept down the gentle slopes of the former shield volcano, destroying everything in its path and deposited a layer of ash many tens of metres thick near the vent and few centimetres thick as far away as ten kilometres.

Because the upper magma chamber was not large, the initial eruption was only a VEI 4 (Volcano Explosivity Index) and erupted a total of ash and lava of just under ½ cubic km DRE (Dense Rock Equivalent). Subsequent eruptions in this period of activity that lasted almost ten thousand years were mostly smaller and added layer upon layer, or strata upon strata, of pyroclastic deposits and lava flows, always much thicker the closer you got to the central vent. Our volcano had now become a symmetrical Stratovolcano with a base radius of about five kilometres and had a prominence of just over 2,500 metres. It was now easily visible and recognisable as a typical volcano. After what seemed the final eruption, the vent had been "plugged" by gas-poor magma that did not erupt but formed a solid plug or Lava Dome, effectively sealing off the vent.

After a short repose of several millennia, our volcano finally had its first very large eruption. With each preceding eruption having enlarged the upper magma chamber, it spanned from four to six km depth and extended laterally roughly two kilometres in every direction. It now contained no less than 13 cubic kilometres of magma while the deep magma chamber may have held as much as ten times more. Of the 13 km3, somewhere around 40% was eruptible. Over the centuries, all seemed calm and serene on the surface. Natural erosion plus a cycle of glaciation and deglaciation had reduced the prominence from 2½ km to just over two. The volcano was now covered with a slowly receding set of glaciers and our distant hominid ancestors must have thought it beautiful, the weather patterns induced - in particular the lenticular clouds - must have filled them with awe. While below, the pressure gradually increased, unnoticed...

Then one day, a critical point was reached and our volcano burst back into life over a period of a few months. First, there had been a series of small, phreatic explosions as ground water inside the volcano became superheated and exploded near the summit, sending pulverised, old rock and ash up to a kilometre or higher above the summit. Meltwater from the glaciers cascaded down the slopes carrying old deposits with it, a mixture of ash and rock turned to clays by volcanic gases, sulphur dioxide which together with water had turned into sulphuric acid which dissolved the rocks. As they reached the valleys below, these thick, muddy clays with the consistency of wet cement poured across the valleys below as lahars. Because these were only precursor explosions - the volcano clearing its throat - the lahars were modest in size, yet deadly to anything caught in their path.

Then the main eruption. Suddenly the summit could no longer resist the enormous pressures from below. It disappeared over 25 km high into the stratosphere in a huge, Plinian explosion, shattered into tiny fragments and was accompanied by vast quantities of magma. The gas contained in the magma formed microscopic bubbles. As these droplets cooled quickly, they burst into incredibly sharp shards of volcanic glass that turned into cement when inhaled, a cement made of volcanic ashes and bodily fluids that slowly choked its victims as far away as fifty kilometres or more downwind from the eruption.

The initial phase of the main eruption lasted only about an hour and a half before the eruption column began to collapse, sending huge flows of clouds that glowed at night, nuees ardentes or pyroclastic flows, miles from the erupting volcano. Then, only some 12 hours into the eruption, the volcano began to collapse into the emptying magma chamber as the weight of the mountain could no longer be supported. This caused further Vulcanian eruptions accompanied by even more devastating base surges of pyroclastic products. Any animal caught near the volcano was instantly cooked by the 7-800°C hot flows. Even ten kilometres away, temperatures of well over 300°C were enough to kill anything caught by them.

When it was all over after less than 48 hours, the volcano had lost almost a kilometre in height. Where the summit and the 400-m wide summit crater had been, now gaped a huge summit caldera just over three km in diameter and almost 500 m deep at its lowest point. The upper magma chamber had been all but destroyed after erupting no less than 4½ cubic kilometres of magma. The area around the volcano was utterly devastated up to between 10 and 25 kilometres by pyroclastic flows and in the years immediately following, lahars caused by annual rainfall. In the following decades, there were a few minor eruptions that began to fill in the summit caldera and form a new central cone. This was not due a new influx of magma from the mantle but the result of readjustment of pressures from surface to deep magma chamber. Also, but not immediately visible, the subsidence had caused radial fractures extending several kilometres in every direction from the former summit and also a series of tangential fractures, ring fractures, about 6 km in diameter, centred on the old summit and roughly following the outline of the now collapsed upper magma chamber.

Our volcano now went into a long period of repose that lasted almost a quarter of a million years as the last dregs of the blob of magma from the subducting plate had been expended. Certainly, there were a few very minor episodes of unrest, but to all intents and purposes, the volcano appeared to be extinct. Then 230,000 years ago, a new cycle of eruptions began. Initially, magma from the deep reservoir made its way along the cracks left by the previous cycle and erupted on the flanks of the old volcano. This resulted in a series of monogenetic cones that eroded away over the subsequent millennia. But there were also two subsidiary stratovolcanic cones built a few kilometres away from the former main vent. Our Shield volcano that had turned Stratovolcano was now also the Central volcano of a volcanic complex.

With the damage from the end of the previous cycle "repaired", the fissures sealed by fresh magma, the central volcano began to fill in the summit caldera and build a new edifice upon the old one. As it steadily gained in elevation, the former subsidiary stratovolcanic cones were swallowed by the rapidly growing main edifice, becoming first side vents where there were a few very minor eruptions before they disappeared forever. This cycle lasted some 50,000 years and when it ended, our volcano had a prominence of almost 3½ kilometres and the radius of the edifice was close to ten. Then there was another long period of dormancy.

Only some 15,000 years ago, a new cycle began. Broadly, it followed the pattern of the previous cycle even if the final, cataclysmic eruption was many magnitudes greater. This time, there was a series of very large eruptions that emptied the by now much enlarged upper magma chamber to the extent that almost the entire edifice disappeared in the ensuing collapse when the roof no longer could bear the weight of the huge edifice. Where it had stood, there was now a large caldera, some 11 x 9½ km in diameter and well over 2½ km deep that slowly filled with water over the following millennia.

Wither now our volcano? Who can tell! Perhaps, it has had its final major eruption before slowly meandering towards extinction. Perhaps another cycle of activity will begin 50,000 or 250,000 years from now. Although some may think they recognise the volcano of our story as Mount Mazama, the precursor of Crater Lake, it is not so. Our volcano is completely fictitious although there are many real-world volcanoes with similar histories. Hope you have enjoyed our little tale!

/ Prunelle

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Just like animals, volcanoes go through a life cycle of birth, growth, decline and finally death; they become extinct. In this installment, we will examine such a cycle of a fictitious volcanic complex and introduce another bucketful of terminology to the reader.

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World Population:

reached 8 billion on November 15, 2022 according to the latest United Nations estimates.

is projected to reach 9 billion in 2037, and 10 billion in 2058.

has doubled in 40 years from 1959 (3 billion) to 1999 (6 billion).

is currently (2023) growing at a rate of around 0.88% per year, adding around 70 million people per year to the total.

growth rate reached its peak in the late 1960s, when it was at 2.09%.

growth rate is currently declining and is projected to continue to decline in the coming years (reaching below 0.50% by 2048, reach 0 in 2086, and decline by -0.11% in 2100) .

a tremendous change occurred with the industrial revolution: whereas it had taken all of human history up to the year 1800 for world population to reach 1 billion, the second billion was achieved in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), the fifth billion in 13 years (1987), the sixth billion in 11 years (1998), the seventh billion and eighth billion in 12 years each (2010 and 2022). During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion.

Sources for the world population counter: For more detailed information:

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