Pipes are damaged from an earthquake, July 4, 2019, in Trona, California. (MATT HARTMAN / AP)

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.

READ MORE: Strongest earthquake in 20 years rattles Southern California

Ferndale, a town of about 15,000 people, is 261 miles (420 km) north of San Francisco and 19.6 miles (31.54km) south of Eureka, California.

There was no risk of a tsunami after the quake, the US tsunami warning system said.