The ski town of Mammoth Lakes, California, sits next to a volcanic depression that the U.S. Geological Survey rates at its highest tier of threat. Long Valley Caldera measures 16 by 32 km, which ...

One of California's riskiest volcanoes has for decades been undergoing geological changes and seismic activity, which are sometimes a precursor to an eruption, but—thankfully—no supervolcanic ...

Beneath the eastern edge of California’s Sierra Nevada sits one of the largest volcanic depressions in North America, a bowl in the landscape formed by a cataclysmic eruption hundreds of thousands of ...