Yellowstone Sits on 'Supervolcano'

The volcanic plume that powers Yellowstone’s geysers and hot springs may be bigger than we thought, and it could someday erupt—not for the first time. The “hotspot” unleashed three major blasts long ago, covering a huge portion of the continent with ash, the BBC reports. Researchers made their discoveries by studying changes in the electrical conductivity of the area’s molten rocks and hot water, marking a shift from a 2009 study that examined seismic waves. Click through for more on the Yellowstone findings. (More Yellowstone National Park stories.)