A 6.5 magnitude earthquake struck off the coast of Northern California today, shaking buildings south of the Oregon border and knocking out power in several coastal communities.
The US Geological Survey said the quake hit at about 4.27pm (12.27am Irish time), about 27 miles from Eureka, a city of about 26,000. No injuries were reported.
Pacific Gas & Electric said power cuts were widespread across most of Humboldt County, affecting about 25,000 customers.
Several traffic lights had collapsed and many residents had reported water, gas and sewer leaks, Humboldt County Office of Emergency Services spokeswoman Jo Wattle said.
"People have chimneys down and we're hearing about minor property damage and lots of glassware broken," she said.
"It was shaking pretty good, then it had a big jolt to it at the end."
Police in Ferndale, the community closest to the quake's epicentre, said the jolt caused plasterwork to fall off City Hall and broke shop windows, strewing the historic central streets with glass.
"I thought a tyre had blown off my truck because it was so hard to keep control of the vehicle," Officer Lindsey Frank said. "Power lines were swaying and I could see people in the fields trying to keep their balance."
Televisions tumbled and objects were knocked off walls in Arcata, a small town home to Humboldt State University, one resident said.
"The whole town is kind of freaked out right now," said Judd Starks, the kitchen manager at a bar and restaurant known as The Alibi. "All the power is out, people are out walking around."
The quake was felt as far south as Capitola in central California, and as far north as central Oregon, USGS geophysicist Richard Buckmaster said.
Arcata and Eureka are about 270 miles north of San Francisco in a coastal area known for periodic earthquakes.
In 1964, a tsunami washed away 11 people in Crescent City, 90 miles to the north of Eureka. It is the only tsunami to take lives in the continental United States.
The National Oceanic and Atmospheric Administration said there was no threat of the quake generating a tsunami.
According to the USGS, the quake hit at a depth of nearly 10 miles. Five aftershocks followed in the 90 minutes after the quake, the biggest registering at a magnitude of 3.8. The San Francisco Bay area was struck by two light earthquakes on Thursday and Friday.
There was a small chance - 5 to 10 % - of another magnitude-6.5 temblor or larger hitting the area over the next week, but the odds would dramatically decrease as time passed, the USGS said.
There was also a 78% chance of a strong and potentially damaging aftershock magnitude-5 or larger over the same period.
The earthquake probabilities are based on statistical observations of past earthquakes in California and are not predictions, the USGS said.