Oregon Public Broadcasting

Scientists recorded more seismic activity off the Oregon Coast this weekend.  As Andrew Theen reports, the so-called earthquake swarm continues to stump the experts.

A swarm of earthquakes sounds menacing, but researchers at Oregon State University say a swarm just means a series of earthquakes occurring  in a short span of time.  But this swarm is unusual for its higher magnitude quakes.

Bob Dziak is a professor at OSU's Hatfield Marine Center.  He says over the past two weeks hundreds of earthquakes were recorded about 200 miles west of Yachats. 

Dziak said swarms usually happen near volcanoes, so scientists are confused.  But he has his theories.

Dziak: "It could be that the Juan de Fuca plate is this small plate that is essentially being crushed by the big Pacific plate and north America.  And it could be that it's some kind of stress in response to that."

Dziak said OSU plans to send a research boat to the area by the end of the week.  Scientists could then check water samples for the presence of volcanic material.