Earthquake intensity map

This map from the USGS shows the intensity of the earthquake as it was felt up and down the California and Oregon coast.

(USGS)

EUREKA, Calif. -- A very strong earthquake that struck offshore rattled the Northern California coast and was widely felt across the region, but authorities said early Monday that there were no reports of any injuries or damage.

The

and was centered 50 miles west of Eureka and about 4 miles beneath the Pacific seabed, according to the

. It was followed by about a half-dozen aftershocks, including one of magnitude 4.6.

The quake was felt widely across the region but both fire and sheriff's officials in Humboldt County said early Monday that they had no reports of any damage or injuries. Humboldt County includes most of the populated areas closest to the epicenter.

"We had some alarms go off and other than that we dodged a bullet," Humboldt County Sheriff's Lt. Steve Knight told

.

The National Tsunami Warning Center said there was no tsunami danger for the region.

"It was a big bump and then it rolled for about 30 seconds," said Diana Harralson, 64, who lives in an apartment in Rio Dell, about 55 miles southeast of the earthquake's epicenter. "It was a real good shaker."

Harralson said some knickknacks fell off the wall, but there was no damage. A California native who has experienced other earthquakes, she said she and her cat slept comfortably through the night.

Amandip Heer, a manager at a 76 Gas Station and convenience store in Eureka, described the quake as a "vibration," but said nothing fell of the shelves at the store, and there was no other damage.

More than

that they felt the quake within hours of it striking, including some across the border in Oregon.

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.

Earthquakes are very common in Eureka, a city of about 27,000 people about 270 miles northwest of San Francisco and 100 miles south of the Oregon state line. Nearby Arcata is home to about 17,000 people and Humboldt State University.

The area experienced a magnitude-7.2 earthquake in 1992 that left 95 people injured and caused millions of dollars in damage, according to the USGS. The earthquake was felt as far south as San Francisco.

It was followed by a magnitude-6.5 earthquake about 12 hours later and a magnitude-6.7 earthquake a few hours after that, both of which caused additional damage.

The area had a magnitude-5.6 earthquake in February, 2012 that did not cause serious damages or injuries.

An offshore magnitude-6.5 quake struck offshore in 2010 and caused bumps and cuts among residents and broke glass in some buildings, but it was about 25 miles closer to land than Sunday night's quake.