East of the Sierra Nevada, near the ski town of Mammoth Lakes, lies one of the most closely watched volcanic depressions in North America. The Long Valley Caldera is an oval basin roughly 20 miles ...

Add Yahoo as a preferred source to see more of our stories on Google. Two long-dormant "supervolcanoes" on two separate continents appear to be stirring to life. Well, maybe. In recent months, more ...

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 ...

To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over.

One year ago, Congress defunded public media. Now that we're 100% community funded, please become a sustaining member or increase your existing membership today. The U.S. Geological Survey deemed the ...