NOAA depiction of the epicenter of Sunday night's earthquake off the Humboldt County coast.
NOAA depiction of the epicenter of Sunday night’s earthquake off the Humboldt County coast.

11:45 a.m. Monday Update: The U.S. Geological Survey has revised its assessment of last night’s quake off the Humboldt County coast, now rating it as a magnitude-6.8 event. About 26 aftershocks have been recorded since the quake, which hit at 10:18 p.m. last night.

U.S. Geological Survey map showing location of Sunday night earthquake and aftershocks.
U.S. Geological Survey map showing location of Sunday night earthquake and aftershocks.

Original post, 12:10 a.m. Monday: The U.S. Geological Survey says a magnitude-6.9 earthquake struck at 10:18 p.m. Sunday night off the Humboldt County coast, about 250 miles northwest of San Francisco.

The Associated Press and Los Angeles Times both quote local officials as saying there were no early reports of damage or injuries. The California Office of Emergency Services reported, via Twitter, that as of 11:30 p.m. it had no reports of trouble from the coast.

The West Coast and Alaska Tsunami Warning Center said there is no danger of a tsunami from the quake.

The quake was centered about 40 miles west of Eureka, the largest town in Humboldt County, and was about 7.5 miles under the seafloor. The initial quake was followed by 10 aftershocks by midnight Sunday, the largest a magnitude-4.6 shake recorded at 10:51 p.m. The USGS “Did You Feel It?” public report page included a smattering of reports from as far away as the Bay Area, the northern Sierra Nevada and the Willamette Valley in Oregon. More than 2,000 reports came from communities around Humboldt Bay.

The offshore region is the site of the Mendocino Triple Junction, where the Gorda, Pacific and North American tectonic plates meet just north of the terminus of the San Andreas Fault.

In April 1992, a 7.2-magnitude quake, followed by 6.5 and 6.7 shocks, violently shook the coast 30 miles southwest of Eureka, causing more than 100 injuries and severe damage in several towns, including Ferndale and Petrolia.

In November 1980, a 7.2-magnitude quake centered just off the coast caused widespread damage around Eureka, including the partial collapse of a freeway overpass south of Eureka.

Author

Dan Brekke

Dan Brekke is a blogger, reporter and editor for KQED News, responsible for online breaking news coverage and specializing in topics ranging from California water issues and the Bay Area's transportation challenges. In a newsroom career that began in Chicago in 1972, Dan has worked as a city and foreign/national editor for The San Francisco Examiner, editor at Wired News, deputy editor at Wired magazine, managing editor at TechTV as well as for several web startups. Since joining KQED in 2007, Dan has reported, edited and produced both radio and online features and breaking news pieces. Dan has shared in two SPJ Norcal "Excellence in Journalism" awards at KQED: in 2012, for reporting on a KQED Science series on water and power in California; and in 2014, for KQED's comprehensive reporting on the South Napa Earthquake. In addition to his 44 years of on-the-job education, Dan is a lifelong student of history and is still pursuing an undergraduate degree. Email Dan at: dbrekke@kqed.org Twitter: twitter.com/danbrekke Facebook: www.facebook.com/danbrekke LinkedIn: www.linkedin.com/in/danbrekke

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