3.4 magnitude earthquake strikes Washington coast amid string of tremors
A 3.4 magnitude earthquake struck the Washington coast near Ocean Shores early Tuesday morning.
According to MyNorthwest’s Earthquake Tracker, the quake struck around 4:11 a.m. The Pacific Northwest Seismic Network reports that it occurred four miles east of Copalis Beach, near Grays Harbor, at a depth of a little more than 21 miles.
“This is quite a small earthquake, as these things go,” said Paul Bodin, manager of the Pacific Northwest Seismic Network at the University of Washington.
“It’s the kind of earthquake that is inside the Juan de Fuca Plate rocks which are being thrust underneath North America,” he said. “So it’s a deep kind of earthquake. These earthquakes, they tend not to have aftershocks … if they did happen, they’d be over with quickly, within a couple hours or days and would be fairly small.”
KIRO 7 reports that residents felt the shake as far as Aberdeen, Hoquiam, Copalis Crossing, and Pacific Beach. The Grays Harbor County Emergency Management is monitoring the situation on the coast.
While small, Bodin says that the seismic network is grateful for the shake up as it provided a few positives.
“One of the things this earthquake did … it provided a test of our earthquake early warning system that we are building,” he said. “It passed the test really good.”
About 12 seconds after the earthquake happened, the seismic network was notified about it with an accurate location.
Series of earthquake tremors through the NW
Tuesday morning’s quake off the coast comes amid recent tremors in southern Washington and Oregon. Seismologists with the Pacific Northwest Seismic Network are in the process of tracking the tremors south of Seattle.
“Tremor bursts have continued to excite and confuse all of us tremor watchers over the past month,” a blog post on the PNSN’s website said last Thursday.
PNSN’s seismologists usually see these tremor events take place in the Pacific Northwest sometime in the late summer, around July or August. That said, they do not currently believe that the tremors showing up early are a precursor to a larger earthquake.
Rather, the thinking is that this is part of a “significant slow-slip,” an event that is fairly common in the region.
A map from the PNSN tracking recent tremors in the Pacific Northwest. (PNSN)
The most recent tremors have mainly been tracked in Oregon, moving up the West Coast from Eugene. Olympia and the area directly south of the state capital mark the areas where Washington has seen its own most recent tremors.
This comes amid a period when tectonic activity in the Pacific Northwest has been scarce.
“It’s very interesting, we’ve actually been in a period for several years now when we’ve had very few earthquakes,” Bodin said. “Seismologists along the entire West Cast are talking about an ‘earthquake drought.’ The few earthquakes we’ve had over the past month are really doing nothing to end that drought. These are small earthquakes and maybe a return to a more normal rate of earthquakes.”
Bodin says that “for years” the Northwest region would experience 1-2 earthquakes a month which were felt by people on the surface. More recently, however, it’s been rare – about six each year.
“We’ll see,” he said. “Perhaps this is the start of a return to a more normal rate of earthquakes. It’s been so slow recently, in earthquakes, we’ll see how things go from this point forward.”