A strong earthquake has hit off the coast of northern California early Friday.
The U.S. Geological Survey says the quake had a magnitude of 6.4 on the Richter scale and occurred in the Pacific Ocean about 482-kilometers northwest of San Francisco. There are no immediate reports of injuries or damage.
On Thursday a 5.3 magnitude earthquake struck southern California. And earlier this week, a 7.2 magnitude quake off the coast of northern California triggered a brief tsunami warning.