Hundreds of earthquakes shake Mount Rainier

Hundreds of tremors shook one of America’s most deadly volcanoes Tuesday morning.

A series of tiny earthquakes that started close to the peak caused Mount Rainier, which the U.S. Geological Survey ranks as the second most dangerous volcano in the Pacific Northwest (behind Mount St. Helens), to tremble, the federal agency said.

The U.S. Geological Survey stated that the earthquakes are not a reason for alarm at this time and do not portend an eruption. The mountain’s surface was not affected by the quakes, the biggest of which had a magnitude of 1.7.

According to the agency, Mount Rainier experiences earthquakes roughly nine times every month. Once or twice a year, swarms of earthquakes occur. The last significant occurrence was in 2009, when a ferocious swarm of over 1,000 earthquakes with a magnitude of up to 2.3 rocked the mountain for three days. Larger swarms are less common.

Swarms of earthquakes are a common feature of volcanic seismic activity, yet they can also occasionally foretell eruptions. There are often additional signs of impending eruptions. Before a 4.7-magnitude earthquake woke Mount St. Helens in 1980, the volcano was rocked by a string of minor tremors. Residents in the vicinity gradually felt the daily tremors as the volcano started to spew ash, steam, and debris.

For at least a century, if not more, Mount Rainier has not erupted. According to the US Geological Survey, there is no tangible proof of an eruption that was reported in 1894 or of eruptions that occurred earlier in the 18th and 19th centuries. Approximately 1,000 years ago was the latest eruption for which there is solid geologic evidence.

According to the U.S. Geological Survey, a vast network of seismometers, infrasound sensors, GPS units, and webcams keep an eye on the active volcano. The organization will keep an eye on seismic activity and provide more information when necessary.