January 10, 2010 Earthquake: Off Coast Northern, California, United States

About 30 people injured and moderate damage to hundreds of homes and buildings in the Eureka-Ferndale area. Felt (VII) at Eureka, Ferndale and Samoa; (VI) at Bayside, Fortuna, Loleta and Rio Dell; (V) at Arcata, Blue Lake, Carlotta, Hydesville, Kneeland, Korbel, McKinleyville, Petrolia, Scotia, Somes Bar and Whitethorn.

Tectonic Summary

This earthquake occurred approximately 35 km WNW of Ferndale, CA in a deformation zone of the southernmost Juan de Fuca plate that is commonly referred to as the Gorda plate. The earthquake's epicenter is northwest of the Mendocino Triple Junction, which is formed by the intersection of the Mendocino fracture zone, the San Andreas fault and the Cascadia subduction zone. The Gorda plate is subducting beneath the North America plate at about 2.5-3 cm/year in the direction N50E. The Gorda plate is also subjected to intense compressive stresses by oblique-convergence of the northwestward migrating Pacific Plate as well as localized eastward spreading at the Gorda Ridge. The resulting internal deformation of the Gorda plate is manifested primarily by intraplate strike-slip events on vertical NE-oriented faults.

Preliminary analysis of the earthquake indicates that it results from slip on a near vertical, left-lateral fault oriented about N47E. Large strike-slip earthquakes like this one are common in the interior of the Gorda plate. There are no reports of this earthquake causing a tsunami. Strike-slip earthquakes are less likely to produce large tsunamis because they cause relatively little vertical ground displacement. Shaking was strongest near the coast line between Petrolia and Eureka, CA, although felt reports for this event extend from as far south and north as Capitola, CA and Eugene, OR, respectively, and as far east as Reno, NV. The maximum recorded shaking was observed in Eureka (33%g), which is sufficient to cause moderate damage.

This is the largest quake to occur in this region since the April 04, 1992 M7.2 Petrolia and the June 15, 2005 M7.2 Gorda plate earthquakes.

(above ref #1053)

A magnitude 6.5 earthquake rocked the Northern California city of Eureka on Saturday, snapping power lines, toppling chimneys, knocking down traffic signals, shattering windows and prompting the evacuation of at least one apartment building. There were no reports of major injuries, but the temblor, which struck at 4:27 p.m. about 33 miles southwest of the coastal city of 26,000, was powerful enough to send people running into the streets, some fearing a tsunami. In the south Eureka fishing village of King Salmon, the 10 seconds of shaking broke power lines and knocked out electricity throughout the isolated seaside community of about 750 people. On Saturday, 25,000 customers lost power, according to Pacific Gas & Electric Co. Water and gas lines were also disrupted. At Myrtle Avenue Pet Center on Hubbard Lane in Eureka, owner Melanie Noe spent the evening picking up shampoo bottles and shattered dog bowls. The only other casualties were the cats' nerves, she said. On the other side of town, lamps and dishes crashed down at Antiques and Goodies, causing a couple to run out of the store, while two women took cover under a table. "We've been through a lot of earthquakes, but I can't recall there ever being any this bad," said store owner Sandra Hall. To the south, floodlights fell at the Humboldt County Fairgrounds, and windows shattered in Ferndale. Farther south, in Redway, shoppers abandoned their carts in a grocery store and raced to their cars. (ref #6206)

Officials […] received 219 reports of damage. Although about 30 people were treated for cuts, bruises, scrapes and anxiety-related illnesses, only one person […] was admitted to the hospital. (ref #6245)

[…] zero deaths, 35 injuries, $43 million in damage. (ref #13955)

$43 million economic losses (ref #13727)