Roughly 18 small earthquakes were recorded off the coast of Washington early Sunday, geologists reported.
The first and largest quake hit around 4:48 a.m. in the Pacific Ocean about 240 miles west of Westport, per the U.S. Geological Survey, which clocked the magnitude at 4.2 with a 10-kilometer depth.
This magnitude of earthquake is fairly common, with 500,000 happening annually, according to Michigan Tech, which notes that earthquakes between magnitudes of 2.5 and 5.4 can be felt but typically cause only minor damage when they strike inland.
Harold Tobin, seismologist and director of the Pacific Northwest Seismic Network, explained that it’s not a cause for concern.
“These types of earthquakes don’t create a tsunami hazard,” he said in a phone interview Sunday night. “They’re, first of all, just not big enough.”
“Quite an active swarm” of smaller earthquakes was recorded Sunday morning as well off Washington’s coastline, according to the Pacific Northwest Seismic Network. The second-largest quake came around 8:04 a.m. at a magnitude of 4.1.
The quakes happened over the course of a few hours, Tobin said, and the activity has “definitely tapered off some since then.”
The quakes struck along the Juan de Fuca Ridge, “NOT anywhere near the Cascadia Subduction Zone,” according to the seismic network.
“They are also not at the Axial Seamount Volcano, which has been predicted by others to be nearing an undersea eruption, though they are farther north along the same ridge,” the seismic network posted on social media. “Finally, this swarm does NOT pose a hazard to the PNW onshore region.”
The Juan de Fuca plate is spreading apart from the Pacific plate, creating new crust of the Earth, Tobin explained.
“It’s just a real sign that the tectonic plates are moving and active,” he added.
