More than 1,000 earthquakes have now been recorded as part of an ongoing swarm at Yellowstone volcano since January.
So far, the swarm was most active between late August and mid-September. In the month of September alone, for example, the swarm, which is located around 12 miles south-south-west of Mammoth Hot Springs near Grizzly Lake, produced more than 500 earthquakes.
In the month of October, the University of Utah recorded 238 earthquakes as part of this swarm, out of a total of 344 in the entire Yellowstone region.
The Yellowstone region is one of the most seismically active areas in the United States. Since 1973, more than 50,000 earthquakes have been recorded in the region, although the vast majority are too small to be felt by humans.