Yellowstone Has Bulged as Magma Pocket Swells

[National Geographic]  Yellowstone National Park's supervolcano just took a deep "breath," causing miles of ground to rise dramatically, scientists report. The simmering volcano has produced major eruptions—each a thousand times more powerful than Mount St. Helens's 1980 eruption—three times in the past 2.1 million years. Yellowstone's caldera, which covers a 25- by 37-mile (40- by 60-kilometer) swath of Wyoming, is an ancient crater formed after the last big blast, some 640,000 years ago.  More...