Earthquake in Cascades not best sign for early warning system

SEATTLE – A magnitude-4.3 earthquake that rumbled under Washington’s Cascade Range early Wednesday was “not a great advertisement” for an early warning system undergoing tests, an official said.

The system noticed the quake 18 seconds late, said John Vidale, director of the Pacific Northwest Seismic Network at the University of Washington.

He noted there were not enough seismometers in the area to respond any faster or more accurately to the initial jolt before shaking arrived.

“Our current station geometry does not serve Eastern Washington well,” Vidale said in an email.

Results would have been better for a quake in the Puget Sound area, where there are more sensors, he added later in a phone call.

The quake at 1:04 a.m. Wednesday was centered about 20 miles north of Ellensburg and 10 miles northeast of Cle Elum in Central Washington. Dispatchers for the Kittitas County Sheriff’s Office said they received calls from people who felt it but did not report any damage.

The Pacific Northwest Seismic Network has been working for two years on a system that would detect an initial fast-moving jolt from a quake and alert people before stronger shaking arrives.