A strong, 6.5-magnitude earthquake hit off the coast of northern California on Saturday, the U.S. Geological Survey said.
There were no immediate reports of damage from the offshore quake, which was 22 miles (35 km) west-northwest of Ferndale, California, at a depth of 10.2 miles (16 km), the USGS said.
The West Coast and Alaska Tsunami Warning Center said there was no tsunami watch or warning in effect, Reuters reported.
Ferndale, a town of about 1,400 people, is 265 miles (426 km) north of San Francisco and 12 miles (19 km) south of Eureka, California.
On Friday, Silicon Valley in northern California, home to a number of large technology companies, was shaken by a light 3.8 magnitude earthquake, following a a 4.1 magnitude quake in the same region on Thursday.