Volcanoes in the United States that have been active since spring woke up, brushed themselves off, and then went back to sleep. Two volcanoes, one in Alaska and one in Hawaii, are experiencing active eruptions that are minimal and not very dangerous.

Volcanoes are rumbling as scientists monitor earthquakes at Washington's Mount Rainier and Alaska's Iliamna volcano.

Wednesday’s magnitude 7.3 earthquake off Alaska’s Aleutian Islands chain struck in a region that has experienced a handful of powerful quakes within the last five years

The United States and Japan concluded a weeklong disaster-response exercise that simulated a magnitude 7 earthquake, the first to bring together U.S. Forces Japan and the country’s newly formed Joint Operations Command.

This is now the largest recorded earthquake swarm at Mount Rainier since seismic monitoring at the volcano began in 1982, the Cascades Volcano Observatory said. With quakes ongoing, the swarm has already surpassed a major event in 2009 “in terms of magnitude, total events, event rate, and energy release.”

One of the most famous mountains in Washington, Mount Rainier, has been rumbling over the last day due to the amplified seismic activity.

Aftershocks from devastating earthquakes in the 1800s near the Missouri-Kentucky border and in Charleston, South Carolina, may still be occurring, a study found.

Earthquakes today in the U.S. could be left over from seismic activity in the 1800s, scientists have found. In a new study, published in the Journal of Geophysical Research: Solid Earth ...