Yellowstone Super Volcano

Picture of a Yellowstone geyser, part of a round-up of the best science discoveries of 2011

Steam rises from Castle Geyser in Yellowstone National Park (file photo).

The Yellowstone volcano is considered to be the largest volcano in the world. It last erupted 70,000 years ago. Most people picture a mountain when they think of a volcano, Yellowstone is almost flat, completely underground. The caldera is over 50 miles wide, and has been rising several inches a year since 2004. An eruption would be very, very bad. It would make Mt. St. Helens look like a ¬†child’s pop gun going off.