Beneath Yellowstone, a volcano that could wipe out U.S.
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We’ve long known that Yellowstone is merely the skin on top of a supervolcano – a giant pool of magma sitting just under the Earth’s surface.

Exactly how giant has been the subject of much speculation.

Until now.

A team from the University of Utah have told the American Geophysical Union Fall Meeting in San Francisco that Yellowstone’s magama chamber is 2.5 times larger than previously thought.

It is an underground cavern measuring some 55 miles by 20 miles and containing between 125 and 185 billion cubic miles of molten rock.

If it blows it will wipe out America – and have enormous impacts on the rest of the world.