The offshore 7.0-magnitude earthquake that triggered a tsunami warning for near-shore communities in California and Oregon late Thursday morning is indicated by orange circles and was among a series of 48 seismic events, according to the U.S. Geological Survey. Image by the U.S. Geological Survey
Dec. 5 (UPI) — A tsunami warning has been lifted after a 7.0-magnitude earthquake hit offshore Cape Mendocino in Northern California Thursday, the U.S. Geological Survey said.
The offshore earthquake occurred at 10:44 a.m. PST and was centered about 62 miles southwest of Ferndale, Calif., the USGS said.
The offshore earthquake triggered a tsunami warning that affected about 5.3 million people in California and Oregon but was ended shortly before noon by the National Tsunami Warning Center.
California Gov. Gavin Newsom declared a state of emergency and told news media he was “concerned about damage” in the northern region of the state.
“It’s another reminder of the state that we live in and the state of mind that we need to bring to our day-to-day reality here in the state of California in terms of being ready for earthquakes,” Newsom said.
Damage assessments are underway, but no damage has been reported in the early afternoon hours.
The quake was felt in the Bay Area, and residents there were advised to move away from the coast after the tsunami warning.
Residents in San Francisco reported feeling a rolling motion for several seconds, followed by smaller aftershocks.
People were evacuated from the San Francisco Zoo and animals there were moved to higher ground.
The BART transit system in the Bay Area was delayed in all directions as commuters were told to seek other transportation means.
Initially, the offshore earthquake raised fears about the potential for deadly currents and wave action.
In its initial alert, the National Weather Service in Santa Cruz warned, “A series of powerful waves and strong currents may impact coasts near you. You are in danger. Get away from coastal waters. Move to high ground or inland now. Keep away from the coast until local officials say it is safe to return.”
It was centered near the Mendocino Fracture Zone in the vicinity of the Mendocino triple junction, where the Pacific, North America and Juan de Fuca/Gorda plats meet.
The USGS said a rupture occurred due to a strike-slip faulting on or near the Mendocino Fracture Zone and this triggered the earthquake and related seismic events.
Earthquakes commonly occur in the region as the Pacific plate and the Juan de Fuca/Gorda plate cause north-south compression, according to the USGS.
A 6.4-magnitude earthquake on Dec. 20, 2022, and a 6.2-magnitude earthquake on Dec. 20, 2021, occurred in the same area.