BELLINGHAM — The Pacific Northwest Seismic Network is monitoring an “out of the ordinary” series of nearly 3,000 small seismic events over the past week that have rattled just northwest of Whatcom County under Vancouver Island.
“If you’ve checked the Tremor Map in the last couple days, you may have noticed an uptick in activity,” the network tweeted Tuesday morning. “Tremors in between ETS (episodic tremor and slip) events are normal, but starting on about Jan. 26th, tremor under Vancouver Island started getting stronger and longer over the next few days.”
Episodic tremor and slip is observed in subduction zones when non-earthquake rumbling, or tremor, and slow slip occur along the zone where one tectonic plate is pushed beneath another. It usually occurs beneath a locked zone of the fault that can generate great quakes, according to the Incorporated Research Institutions of Seismology. Tremor can release enough energy to equal a 7-magnitude quake, though its rumblings are rarely felt.
As of early Tuesday afternoon, the network’s tremor map shows 2,909 epicenters, most under southern and central portions of the island in British Columbia, but a handful were even recorded in the San Juan Islands on the U.S. side of the Haro Straight.
