Hundreds of earthquakes are detected at or near Mount Rainier each year, though typical swarms are smaller than what started last night.

Hundreds of earthquakes have been detected at Mount Rainier so far Tuesday morning in the largest such swarm at the active stratovolcano since 2009, according to the U.S. Geological Survey.

A swarm of small earthquakes began early Tuesday morning beneath Mount Rainier, with more than 400 minor tremors recorded as of midday, according to scientists with the U.S. Geological Survey and the University of Washington.