Eureka Earthquake 1/9/2010

January 9, 2010 Mw6.5 Gorda Plate Earthquake offshore of Northern California

Summary Report January 13, 2010 compiled from the USGS, Berkeley Seismological Laboratory, Times Standard,

Humboldt State University, and the Redwood Coast Tsunami Work Group

The Earthquake

The earthquake occurred at 4:27 PM PST January 9, 2010 (00:27 UTC 1/10/10). It was centered at a

depth of about 29 km (19 miles) beneath the earth’s surface, but the depth accuracy is relatively poor for

offshore earthquakes and located offshore, 21 miles NW of Cape Mendocino, 23 miles WNW of

Ferndale and 29 miles WSW of Eureka. The preliminary information issued by the West Coast Alaska

Tsunami Warning Center four minutes after the earthquake gave a magnitude of 6.4, which was changed

to 6.5 after review by seismologists at the USGS. Analysis of the earthquake indicates that slip occurred

on an unnamed, near-vertical, left-lateral fault oriented about N47E within the Gorda plate.

... the UC Berkeley Seismological Laboratory estimated a fault lengthof about 25 km (16 miles) and rupture proceeded unilaterally to the southwest. The peak estimated slip (offset) between the two sides of the fault as2.4meters (8 Feet)

http://www.eqclearinghouse.org/20100110-eureka/wp-content/uploads/2010/01/summary_report_1_13.pdf

Google Earth image of the January 9 mainshock (arrow) and aftershocks as of 1/13. Dashed lineshows the location of the probable fault source and black arrows show the direction of slip.

Seismograph traces for Eureka 6.5 magnitude earthquake

http://www.flyingsnail.com/201001.html