A 7.0 magnitude earthquake shook off the coast of Northern California Thursday, December 5th at 10:44 a.m., prompting phones to rattle from pushed ‘Tsunami warning” notifications.
Just before 11 a.m. on Thursday, December 5th, a 6.6 magnitude earthquake struck off California’s Redwood Coastal region, about 40 miles northwest of Ferndale, California. The earthquake was later increased to a 7.0 magnitude, officially making it the largest and strongest tremor to strike the northern coast of the state in 32 years; the 1991 Cape Mendocino earthquakes produced three separate tremors, one of which registered 7.2 M and sent small tsunami waves along the Pacific Northwest; the shocks collectively cost $75 million in damages, most of which was from bridge collapses and road damages.
The 2019 Ridgecrest earthquakes — the strongest in the series registering 7.1 M — caused significantly more damage … to the tune of at least $5.3B. 20 years prior, and left three people injured. The 1999 Hector Mine Earthquake, shook the eastern part of California with a 7.1 magnitude strength on October 16th of the quake’s namesake year. It caused minimal damage and no injuries or deaths related to the earthquake were reported because of its remote epicenter in the Mojave Desert.
Good morning Redwood Coast, CA. Did you feel the magnitude 7 earthquake about 40 miles northwest of Ferndale? See: https://t.co/S70cc4RQRF The #ShakeAlert system was activated. @Cal_OES @CAGeoSurvey @UOHazardsLab @OregonOEM pic.twitter.com/gRpZonDpaT
— USGS ShakeAlert (@USGS_ShakeAlert) December 5, 2024
Today’s earthquake was also incredibly shallow, originating 10 km — about 6 miles in Freedom Units — below the earth’s surface, making it much more dangerous. (Earthquakes and other tectonic activities that transpire closer to the earth’s surface transfer more kinetic energy upward; the lack of depth means generated energy has less vertical space to dissipate outward.)
Moments later, the state’s emergency services network issued a tsunami warning, urging those in affected areas to avoid coastlines and seek higher ground immediately — a move not too dissimilar from the 2022 Tonga tsunami event.
“Tsunami warnings mean that a tsunami with significant inundation is expected or occurring,” the California Office of Emergency Services said in the warning. “Warnings indicate that widespread dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after the initial wave arrival.” As a result of the tremor, BART has stopped trains traveling through the Transbay Tube for the time being.
Many schools, businesses, community centers, and other hubs for people located along the affected coastlines have been temporarily evacuated out of an abundance of caution; no mandatory evacuation orders are in place as of publishing; if a tsunami is observed, it’s expected to strike the San Francisco Bay Area coastline around noon.
This is a breaking story, and we’ll share more updates as they come.
Update 12:10 p.m.: All tsunami warnings in effect along the California and Oregon coastlines have been canceled.
