There were no immediate reports of damage or injuries.

 

The magnitude 7 quake struck at about 7.50pm (2350 GMT) on Tuesday, southwest of the coastal community of Crescent City and 480km northwest of San Francisco, according to the US Geological Survey.

 

Witnesses felt buildings shaking along the California coast but there were no immediate reports of damage.

 

A tsunami warning was briefly sounded from the California-Mexico border north to Vancouver Island, in Canada, but was called off about an hour after the quake hit.

 

"It appears from the mechanism of the earthquake that this was a strike-slip event so the motion was horizontal, not the vertical displacement that typically leads to a tsunami," said Ved Lekic, a seismologist at the University of California Seismographic Station in Berkeley.

 

Rolling sensation

 

"It was just a rolling sensation," said Jim Andresen, a fire captain in Humboldt County who is stationed just outside Eureka. "I've felt worse in the past. It didn't seem like it was that bad, lasted probably 15 seconds."

 

"It appears from the mechanism of the earthquake that this was a strike-slip event so the motion was horizontal, not the vertical displacement that typically leads to a tsunami"

Ved Lekic, 
seismologist

Xiojin Yuan, the owner of the beachfront Hampton Inn and Suites in Crescent City, said police quickly told him to evacuate the guests at his 53-room hotel.

 

"People evacuated in a really orderly way. The police and firefighters in Crescent City did an excellent job," Yuan said.

 

He stayed alone at the hotel to make sure no one was left behind. "My car was the only one in the parking lot," he said.

 

The area hit is where the North American, Pacific Ocean and Juan de Fuca plates converge and has earthquakes of this magnitude about once a decade, said Lucy Jones, the scientist in charge of the US Geological Survey office in Pasadena.

 

Crescent City is the site of the only known tsunami to cause deaths in the continental United States.

 

Eleven people died and 29 city blocks were washed away when a tsunami spawned by a quake hit the coastal community in 1964.