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World’s largest “supervolcano” is even bigger than previously thought
By The Conversation May 2, 2015
Seismologists have discovered a massive magma reservoir beneath the Yellowstone supervolcano in Wyoming, US, that suggests its volcanic system could be more than 5.6 times larger than was previously thought.
Although it was already known that Yellowstone had one magma reservoir, located about 5-16km (3-10 miles) below the surface, the new study, published in Science, has revealed another, much larger reservoir sitting directly below the first, located around 20-50km (12-30 miles) below the surface.
This reservoir is thought to have a volume of around 46,000 cubic km – compared to a volume of around 10,000 cubic km for the shallow reservoir.
To make their discovery scientists analysed the vibrations made by earthquakes that passed beneath the volcano. The technique not only sheds light on this volcano’s potentially life-threatening eruptions but it could also help us understand other volcanoes such as Calbaco, which is currently erupting in Chile.
Sleeping Beauty
Yellowstone volcano is composed of an immense volcanic crater – known as a caldera – more more than 70km (44 miles) in length, most of which lies within Yellowstone National Park. The volcano rarely erupts lava (it last did so about 70,000 years ago, but the magma lying beneath the surface gives rise to spectacular geothermal features, such as geysers and colourful hot springs.
The last large eruption at Yellowstone was 64,000 years ago, and ejected around 1,000 cubic kilometres (240 cubic miles) of volcanic material. This cataclysm created the Yellowstone caldera. To get an idea of the scale of this, the largest eruption in recorded history, Mount Tambora in 1815, erupted about a sixth of that.
Magma reservoirs are thought to occur beneath most volcanoes, and play a crucial role in the dynamics of eruptions. However, they are too deep, and conditions within them too extreme, to be measured directly so volcanologists have to infer information about them using other means, such as measuring seismic waves.
These waves travel more slowly when they pass through molten rock, and accordingly the group were able to use the velocities of the earthquake waves to infer the presence of a large, deep zone of partially molten material.
Carbon footprint explained
The magma stored in the deeper reservoir probably doesn’t cause eruptions at Yellowstone directly. Instead, it likely acts as a “feeder” for the smaller, shallower reservoir – which is the ultimate source of the volcano’s catastrophic eruptions.
Scientists had suspected the existence of a second magma reservoir at Yellowstone for some time, but this new evidence is among the strongest support of the theory to date.
The discovery of this second magma reservoir may also help to explain a mysterious feature of the Yellowstone volcano: its carbon footprint. Carbon dioxide gas is commonplace at volcanoes (it is given off by rising magma), but Yellowstone’s output, which is around 45,000 tonnes of CO2 each day, was too high to be explained by a single magma reservoir. But according to the study’s authors, the presence of the new reservoir is enough to account for the volcano’s CO2 flux.
If the high-resolution seismic imaging technique used in the study could be repeated at other volcanoes whose deep structure is poorly understood – such as Calbuco volcano in Chile – volcanologists might eventually be able to understand how such eruptions take place. The first stirrings of volcanic eruptions happen far below the surface. If researchers can emulate the findings at Yellowstone at other volcanoes, it can only tell us more about the risks they pose.
By Robin Wylie, PhD researcher in Volcanology at UCL
Nine months ago
If This Supervolcano Erupts, Two-Thirds of America Will Be Screwed
Deep in America’s northwest, there lies a supervolcano that, if erupted, has the potential to wipe out the majority of the United States.
What is a supervolcano exactly?
I think the name says it all, but officially, scientists define it as a volcano capable of an eruption thousands of times greater than any ordinary volcanic explosion.
These supervolcanoes burst when a growing pressure of molten rock, or magma, rises up from the Earth’s mantle.
When the crust can’t contain the buildup anymore — boom.
In historic times, we luckily haven’t experienced a supervolcano explosion. The most recent eruption occurred 27,000 years ago in New Zealand.
But, mankind isn’t out of the woods yet. Deep below Yellowstone National Park in Wyoming lies a supervolcano that is very much alive.
A Volcanic Winter
A massive underground chamber filled with magma sits miles below the surface in America’s oldest national park.
Though scientists are mixed as to whether the place could blow anytime soon, there is one thing they do agree on — if it did, it would push much of Earth to the verge of extinction.
It’s immediate effects would be deadly enough, with some estimates saying that 87,000 people would be killed instantly.
A 10-foot layer of ash would spread up to 1,000 miles away, leaving two-thirds of the country completely uninhabitable.
Once the plume rises high into the stratosphere, the released sulfuric gases would mix with the Earth’s water vapor, which National Geographic reports could launch the country and other parts of the globe into a “volcanic winter.”
Essentially, the United States and much of the world would be brought to its knees.
But the carnage doesn’t stop there. The spread of volcanic ash, rocks and gas would immediately cease any sort of air transportation in much of the world.
Just take into account the traffic shutdown following the 2010 Eyjafjallajökull eruption in Iceland. The relatively small explosion caused the closure of large swaths of European airspace, as well as a six-day travel ban in the impacted area.
Those who do survive would be left with a big bill too. Doug Bausch, a senior scientist at FEMA, told WND that such a scenario would cause an estimated $3 trillion in damage for North America.
Could it Happen In Your Lifetime?
The last time Yellowstone erupted — roughly 640,000 years ago — the American continent was devastated, with volcanic materials reaching as far as Louisiana over 1,500 miles away.ast decade, there has been some increased activity at the site. Since 2004, the supervolcano has been rising and just this month, roads were closed in Yellowstone after extreme heat from below was melting the asphalt on roads up above.
An explosion of “volcanic winter” magnitude, however doesn’t seem likely according the U.S. Geological Survey. They say that the chances of a large-scale eruption at Yellowstone “are exceedingly small in the next few thousand years.”
Of course, other scientists (and the conspiracy theorist inside all of us) are a bit more skeptical. See the thing is, these explosions are highly unpredictable. I think the Huffington Post said it most accurately.
“The bulging pocket of magma swishing around beneath Old Faithful might never blow its lid again. Or, it might put on a surprise fireworks show next Independence Day. Scientists just don’t know.”
I guess it just depends who you want to believe. Personally, I’d like to go on living without worrying about choking to death on toxic ash.
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