"Yellowstone National Park is pristine wilderness, full of scenic landscape and iconic hot-pools and geysers that attract tens of thousands of visitors every year.

But it’s what lies beneath that has scientists scurrying.

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 that measures some 55 miles by 20 miles and runs between 3 and 9 miles below the earth.


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