Active Volcano Mt. Rainer Shaken By ‘Swarm’ Of 23 Earthquakes

Don’t panic – it’s only an active volcano. What’s the worst that could happen?

Some two dozen earthquakes have shaken Washington State’s Mt. Rainer over the past two weeks – but seismologists say people who live nearby shouldn’t panic.

“In the past, these swarms last a couple of days to a week or so and then die out,” said Paul Bodin, of the Pacific Northwest Seismic Network at the University of Washington.

The first of the 23 quakes struck on Sept. 11 near the volcano’s summit. The largest of the quakes registered magnitude 1.6. During the same period, Mexico experienced two of the deadliest earthquakes in decades.  

According to the Seattle Times, earthquake swarms typically don’t signify that an eruption is imminent.

“So I’m treating this as a single eyebrow raised halfway,” [Bodin] wrote. “Yeah, I see you and will be watching, but I don’t think you’re going to attack.”

Most volcanic quake swarms are caused by changes in temperature or groundwater pressure underneath the volcano that causes cracking in the rocks. The recent quakes have been shallow, suggesting that they are not connected to the deep movement of magma – which would be a much more ominous signal.

While we might be tempted to dismiss the ongoing quake swarms under normal circumstances, persistent rumblings underneath another powerful volcano located two states over in Wyoming. The Yellowstone Caldera has experienced more than 1,400 low-level quakes since mid-June, alarming scientists who say that an eruption of the yellowstone “supervolcano” could cause potentially hundreds of thousands of deaths across the US.  Those quakes followed the strongest earthquake recorded in Montana in more than three decades. Anecdotally, it would seem, seismic activity across the US appears to be on the rise.

To be sure, the ST said Rainier experienced similar upticks in the past two years, and a more sustained episode in 2009.

But totally writing off the threat seems foolish.