About To Blow? Supervolcano Could Wipe Out Most Of America... And Scientists Fear It May Be Due To Erupt
The giant magma pool could be closer to erupting than previously thought - and a similar super-eruption almost wiped out humans 74,000 years ago
The magma pool under Yellowstone is far larger than the one under Mount Etna, pictured here spewing lava
Supervolcanoes with the power to destroy human civilisations may have much shorter fuses than was previously thought, scientists believe.
The news could be bad for the US, where a supervolcano is said to be simmering beneath Yellowstone National Park.
If it erupted, two thirds of the country could be rendered uninhabitable.
Supervolcanoes are fuelled by giant pools of magma that form deep underground.
Geologists had thought it took between 100,000 to 200,000 years for a supervolcano magma pool to build up enough pressure to erupt.
But the new study suggests that the giant magma bodies may only exist for a few thousand years, or even a few hundred, before exploding.
A magma reservoir six miles below Yellowstone has been rising at a record rate since 2004.
National treasure: The sun rises near the Black Sand Basin in Yellowstone National Park
The Wyoming park sits above a gigantic plume of hot and molten rock that begins at least 400 miles beneath Earth’s surface and rises to 30 miles underground, where it widens to about 300 miles across.
Blobs of magma occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone Caldera.
Resembling the lid of a cooking pot, the caldera formed when the last super-eruption occurred 600,000 years ago.
The supervolcano has erupted a total of three times in the last 2.1 million years. Scientists believe it could be due to erupt again.
A full scale eruption at Yellowstone would be 1,000 times more powerful than the volcanic blast that tore apart Mount St Helens in 1980.
There is evidence that a similar super-eruption in Indonesia 74,000 years ago came close to wiping out the entire human species.
The new study was based on analysis of a super-eruption that occurred in eastern California 760,000 years ago.
Several independent lines of evidence indicated that the magma pool erupted within a few thousand years, perhaps within a few hundred years, covering half the North American continent with smouldering ash.
The scientists based their estimate on quartz crystallisation rates. Previous studies have relied on the growth of zircon crystals, which is said to be a less accurate method.
The research is published in the online journal Public Library of Science ONE.
Lead scientist Dr Guilherme Gualda, from Vanderbilt University in Nashville, Tennessee, said: “Our study suggests that when these exceptionally large magma pools form they are ephemeral and cannot exist very long without erupting.
“The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.”
He said regions such as Yellowstone should be monitored regularly to provide advance warning of a catastrophic super-eruption.