A 6.9 earthquake hit about 48 miles off the coast of Eureka in Humboldt County Sunday night, according to the U.S. Geological Survey.
Police in Eureka said the shaking lasted about 20 to 30 seconds. And so far, there are no reports of injuries nor major damage.
The quake was reported at 10:18 p.m. with a depth of 4.3 miles, according to the USGS.
A tsunami was not expected for North America's West Coast, according to the National Tsunami Warning Center. The agency did not issue a tsunami watch, warning or advisory.
At least 10 aftershocks were recorded, including a magnitude 4.6 about half an hour later.
There was a 90 percent chance that a “strong and possibly damaging” magnitude 5.0 or larger aftershock would strike in the next seven days, according to the Northern California Earthquake Data Center.