EUREKA, Calif. -- A powerful magnitude-6.9 earthquake struck in the Pacific Ocean offthe California coast early Monday, the United States Geological Survey reported.
The quake hit about 50 miles west of Eureka and occurred at 10:18 a.m. PDT, 4.3 miles beneath the seabed, according to the USGS.
It was followed by about a half-dozen aftershocks, including one of magnitude-4.6.
There is not believed to be any threat of a tsunami, according to the Pacific Tsunami Warning Center.
The Humboldt County Sheriff's Department, which oversees most of the populated areas near the quake, says there have been no calls about damage or injuries.
Jana Pursley, a geophysicist with the National Earthquake Information Center, said that based on the area's tectonics and past temblors, damages or casualties were unlikely.