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Over 4,100 earthquakes strike west of Puget Sound, but you can’t feel them

Published on September 5, 2019

Pacific Northwest Seismic Network recent events in the Puget Sound region.
Pacific Northwest Seismic Network recent events in the Puget Sound region. Image Credit: PNSN, August 28, 2019.

West of Puget Sound, the ground is trembling — but even if you live over there, you probably wouldn’t know it.

An episodic tremor and slip (ETS) event appears to be underway, according to scientists at the Pacific Northwest Seismic Network.

ETS tends to happen once every 14 months or so, when the Cascadia subduction zone gets a little stir crazy. So it starts to move … very slowly.

“These plates are basically moving half an inch over the course of a couple days, so it kind of jiggles enough that our most sensitive instruments can feel,” John Vidale, University of Washington professor of Earth and Space Sciences and director of the UW-based Pacific Northwest Seismic Network (PNSN), told SeattlePI in 2017 during a similar event. “But people can’t.”

“It has continued strongly for the past five days, first with a slight migration to the south to fill in the area north of Seattle where the earlier tremor back in mid April had progressed from the south,” Steve Malone, PNSN professor emeritus, said in an update released Aug. 24.

And yet, you can’t feel the tremors. The highest magnitude quake in the last month registered at 2.3 on Aug. 19. Over 4,100 epicenters have been recorded during the month of August on and near the Olympic Peninsula.


Continue reading at SeattlePi.

Originally written by Natalie Guevara for SeattlePi.
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