Yellowstone National Park, which covers parts of Wyoming, Idaho and Montana, lies on top of a supervolcano that could effectively wipe out the United States if it were to explode. The last time it did, 640,000 years ago, it expelled 240 cubic miles (think about that) of rocky debris into the sky.
Early Thursday morning, residents of southern
Montana feared the worst when a 5.8 magnitude earthquake shook the
region. Though its epicenter was only 230 miles from Yellowstone, the
United States Geological Survey (USGS) says the seismic activity was not
irregular, and the supervolcano is not expected to erupt anytime soon.
Related: Yellowstone supervolcano hit by hundreds of earthquakes