[Valin]

America's Explosive Park
By Larry O'Hanlon
http://dsc.discovery.com/convergence/supervolcano/under/under.html

Yellowstone National Park sits atop a subterranean chamber of molten rock and gasses so vast that the region, known for its geysers and grizzlies, is arguably one of the largest active volcanoes in the world.

Granted, it's not your typical volcano, either in scale (it's huge), appearance (it's a vast depression, not a single mountain) or frequency of eruption (at least hundreds of thousands of years apart).

But it is active, and the evidence is everywhere.

A relatively close-to-the-surface magma chamber — as close as 5 miles underground in some spots — fuels thousands of spewing geysers, hissing steam vents, gurgling mud pots and steaming hot springs that help make Yellowstone such an otherworldly and popular tourist attraction, with 3 million summer visitors.

Molten rock and gas in a chamber near the Earth's surface is similarly present below "traditional" cone-shaped active volcanoes, like Mount St. Helens in Washington state.

But there are differences. Huge differences.

The crater atop Mount St. Helens is about 2 square miles. The Yellowstone "caldera" — a depression in the Earth equivalent to a crater top — is some 1,500 square miles.

(snip)

[Cheburashka]

Yeah, Yeah, trust the government to screw everything up.

"No, no! It's not a supervolcano, it's a National Park!"

Instead they should have declared it surplus equipment, sold it to the Chinese, who would transport it to China.

Then it's their problem.

[Old Professer]

On the other hand, if a hugely fat woman with a bottom surface of two square feet sits on the cabin floor of a 747 the aisle is blocked, if she then is helped to her feet and made to stand on a .02 square inch, 3 inch spike high-heel shoe she'll fall about 30,000 feet right through the bottom of the plane.

[diamond6]

Yes, Yellowstone is very dangerous and worrisome.