6.4-magnitude quake strikes off northern California —USGS

SAN FRANCISCO — A powerful earthquake struck off the coast of northern California early Tuesday, triggering small rockslides and cutting power to thousands, but there were no immediate reports of major damage or casualties.

The relatively shallow 6.4 magnitude quake hit 25 miles (40 kilometers) southwest of the port city of Eureka, in Humboldt county, the US Geological Survey (USGS) said.

In a preliminary assessment, the USGS said there was a low likelihood of casualties.

The National Tsunami Warning Center said a tsunami was not expected.

Power supplies appeared to have been hit, with nearly 60,000 customers without electricity in Humboldt County, according to poweroutage.us.

"Power is out across the county. Do not call 911 unless you are experiencing an immediate emergency," Humboldt County Office of Emergency Services tweeted.

Around a dozen small aftershocks were reported in the area, which is 250 miles northwest of San Francisco, USGS said.

One roadway buckled, blocking access to the town of Fernbridge, Dania Romero, a reporter for KAEF television station, tweeted.

Photos and videos posted to social media showed shattered windows, items in homes tossed from shelves and a supermarket aisle littered with spilled goods.

Debris and small rockslides were reported along a central route from Humboldt county to central California.

California is regularly shaken by tremors and seismologists say a quake capable of causing widespread destruction is almost certain to hit the state in the next 30 years.

A 6.7-magnitude earthquake in 1994 in Northridge, northwest of Los Angeles, left at least 60 people dead and caused an estimated $10 billion in damage, while a 6.9 quake in San Francisco in 1989 claimed the lives of 67 people. — Agence France-Presse