A 7.0 magnitude earthquake shook a large area of Northern California on Thursday, knocking items of grocery store shelves, sending children scrambling under desks and prompting a brief tsunami warning for 5.3 million people along the U.S. West Coast.

The quake struck at 10:44 a.m. west of Ferndale, a small city in coastal Humboldt County, about 130 miles (209 kilometres) from the Oregon border, the U.S. Geological Survey said.

It was felt as far south as San Francisco, some 270 miles (435 kilometres) away, where residents felt a rolling motion for several seconds. It was followed by smaller aftershocks.

There were no immediate reports of major damage or injury.

The tsunami warning was in effect for roughly an hour. It was issued shortly after the temblor struck and covered nearly 500 miles (805 kilometres) of coastline, from the edge of Californias Monterey Bay north into Oregon.

It was a strong quake, our building shook, were fine but I have a mess to clean up right now, said Julie Kreitzer, owner of Golden Gait Mercantile, a store packed with food, wares and souvenirs that is a main attraction in Ferndale.

We lost a lot of stuff. Its probably worse than two years ago. I have to go, I have to try and salvage something for the holidays because its going to be a tough year, Kreitzer said before hanging up.

The region -- known for its redwood forests, scenic mountains and the three-county Emerald Triangles legendary marijuana crop -- was struck by a 6.4 magnitude quake in 2022 that left thousands of people without power and water. The northwest corner of California is the most seismically active part of the state since its where three tectonic plates meet, seismologist Lucy Jones said on the social media platform BlueSky.

Shortly after the quake, phones in Northern California buzzed with the tsunami warning from the National Weather Service that said: 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.

Numerous cities urged people to evacuate to higher ground as a precaution, including Eureka.

In Santa Cruz, authorities cleared the main beach, taping off entrances with police tape. Aerial footage showed cars bumper-to-bumper heading to higher ground Thursday morning on California highways 1 and 92 in the Half Moon Bay area south of San Francisco.

I thought my axles had fallen apart, said Valerie Starkey, a Del Norte County supervisor representing Crescent City, a town of fewer than 6,000 near the Oregon border. Thats what I was feeling ... My axles are broken now. I did not realize it was an earthquake.

Cindy Vosburg, the executive director for the Crescent City-Del Norte County Chamber of Commerce, said she heard alarms sound just before shaking began and the citys cultural center downtown started to creak.

The earthquake seemed to go on for quite a few seconds. It was a rolling earthquake, Vosburg said. Just as it would start to subside, the building would roll again.

Vosburg, a former resident of the San Francisco Bay Area and the Central Valley, said it was the strongest earthquake she felt since the 1989 Loma Prieta quake struck Northern California.

Gov. Gavin Newsom said he has signed off on a state of emergency declaration to quickly move state resources to impacted areas along the coast. State officials were concerned about damages in the northern part of the state, Newsom said.

White House Spokesperson Jeremy Edwards said President Joe Biden was briefed on the earthquake and that FEMA officials are in touch with their state and local counterparts in California and Oregon.

Crews in Eureka, the biggest city in the region, were assessing if there was any major damage from the quake, Eureka Mayor Kim Bergel said. Bergel, who works as a resource aid at a middle school, said lights were swaying and everyone got under desks.

The kids were so great and terrified. It seemed to go back and forth for quite a long time. She said. Some children asked, Can I call my mom.

The students were later sent home.

In nearby Arcata, students and faculty were urged to shelter in place at California State Polytechnic University, Humboldt. The campus in was not in the tsunami hazard zone and after inspections, all utilities and building systems are normal and operational, the university said in a statement.

Humboldt County Sheriff William Honsal said residents experienced some cracks in their homes foundations, as well as broken glass and windows, but nothing severe. There also has been no major infrastructure problems, building collapses or roadway issues, and no major injuries or deaths have been reported, he said.

Honsal said he was in his office in the 75-year-old courthouse in downtown Eureka when he felt the quake.

Were used to it. It is known as earthquake country up here, he said. It wasnt a sharp jolt. It was a slow roller, but significant.

Michael Luna, owner of a Grocery Outlet in Eureka, said that besides a few items falling off shelves, the store on Commercial Street was unscathed by the earthquake.

We didnt have any issues but a couple of deodorants fall off.... I think the way the earthquake rumbled this time, it was a good thing for our store because the last earthquake was a huge mess, he said.

They evacuated customers and closed their doors temporarily until officials lifted the tsunami warning, he said, rushing off the phone to attend to a growing line of customers at check-out.

The San Francisco Bay Area Rapid Transit District, known as BART, stopped traffic in all directions through the underwater tunnel between San Francisco and Oakland, and the San Francisco Zoos visitors were evacuated.

Dave Snider, tsunami warning coordinator for the Tsunami Warning Center in Alaska, said the computer models indicated that this was the type of earthquake that was unlikely to cause a tsunami and gauges that monitor waves then confirmed it, so forecasters cancelled the warning.

This quake was a strike-slip type of temblor that shifts more horizontally and is less prone to cause tsunamis, unlike the more vertical types, said National Weather Service tsunami program manager Corina Allen in Washington state.

The California Geological Survey says the states shores have been struck by more than 150 tsunamis since 1800, and while most were minor, some have been destructive and deadly.

On March 28, 1964, a tsunami triggered by a powerful earthquake in Alaska smashed into Crescent City hours later. Much of the business district was leveled and a dozen people were killed. More recently, a tsunami from a 2011 earthquake in Japan caused about US$100 million in damages along the California coast, much of it in Crescent City.