SAN FRANCISCO — Northern California was rattled by a magnitude 7 earthquake off the coast of Humboldt County Thursday, prompting a tsunami warning for a wide swath of the region.
The earthquake occurred at 10:44 a.m. with an epicenter under the Pacific Ocean, about 70 miles southwest of Eureka and 110 miles northwest of Mendocino. Shaking on land was quite strong in the Eureka area, said Elizabeth Cochran, seismologist with U.S. Geological Survey said.
The earthquake was widely felt across California’s North Coast. State Sen. Mike McGuire said in a social media post that there was a mandatory evacuation order in Crescent City due to the tsunami threat.
“All residents should head to higher ground immediately,” McGuire wrote.
The tsunami warning extends from Oregon to just north of Santa Cruz.
“Tsunami warnings mean that a tsunami with significant inundation is expected or occurring. Warnings indicate that widespread dangerous coastal flooding accompanied by powerful currents are possible and may continue for several hours after the initial wave arrival,” officials said in a bulletin.
A second smaller 5.8 magnitude quake also hit around Cobb, Calif. There were no immediate reports of damage.
According to preliminary shaking data from the U.S. Geological Survey, “very strong” shaking may have been felt in the towns of Petrolia and Ferndale. “Very strong” shaking, as defined by the Modified Mercalli Intensity Scale, can cause chimneys to break and cause considerable damage in poorly built or badly designed structures.
The U.S. Geological Survey said strong shaking may have been felt in Eureka. Generally speaking, “strong” shaking can cause heavy furniture to move and cause plaster to fall.
In the past 10 days, there have been two earthquakes of magnitude 3.0 or greater centered nearby.
An average of five earthquakes with magnitudes between 7.0 and 8.0 occur per year in California and Nevada, according to a recent three year data sample.
The earthquake occurred at a depth of 6.2 miles. Did you feel this earthquake? Consider reporting what you felt to the USGS.
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