A strong 6.4-magnitude earthquake struck off the coast of northern California on Tuesday, United States Geological Survey said.
The earthquake was at a depth of 16.1km, USGS said, adding that it struck 12km west-southwest of Ferndale, California.
Ferndale, a town of about 15,000 people, is 420 km north of San Francisco and 31.54km south of Eureka, California.
There was no risk of a tsunami after the quake, the U.S. tsunami warning system said.