Unusual Earthquake Swarm Off Oregon Coast Puzzles Scientists

ScienceDaily

(Apr. 14, 2008) — Scientists at Oregon State University’s Hatfield Marine Science Center have recorded more than 600 earthquakes in the last 10 days off the central Oregon coast in an area not typically known for a high degree of seismic activity.

This earthquake “swarm” is unique, according to OSU marine geologist Robert Dziak, because it is occurring within the middle of the Juan de Fuca plate – away from the major, regional tectonic boundaries.

“In the 17 years we’ve been monitoring the ocean through hydrophone recordings, we’ve never seen a swarm of earthquakes in an area such as this,” Dziak said. “We’re not certain what it means. But we hope to have a ship divert to the site and take some water samples that may help us learn more.” The water samples may indicate whether the process causing the earthquakes is tectonic or hydrothermal, he added. the rest