There are typically only about nine earthquakes detected per month at Mount Rainier and swarms usually occur once or twice each year, the USGS said. Even so, swarms are generally

Hundreds of small earthquakes have been detected at Mount Rainier in Washington in an earthquake swarm, the largest number seen in more than 15 years, according to geologists. The U.S. Geological Survey says the Cascades Volcano Observatory and Pacific Northwest Seismic Network at the University of Washington started to detect the earthquakes just before 1:30 a.