2:05 p.m.

A series of powerful aftershocks rattled California’s North Coast on Thursday following a massive 7.0 offshore earthquake. The aftershocks, ranging in magnitude from 2.5 to 4.7, struck over a span of about two hours, keeping locals on edge.

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A review of data from the United States Geological Survey indicates the strongest aftershock, a 4.7 magnitude tremor, hit at 10:46 a.m. This was one of many aftershocks that hit throughout the day, with the majority clustered within 10-40 miles of Petrolia.

Notably, the majority of the aftershocks occurred within the first hour of the main earthquake, with at least 10 of them recorded between 10:44 and 11:44 a.m. The tremors were felt across a wide area, including nearby Ferndale.

12:55 p.m.

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SFGATE reached out to emergency services from Ferndale and Rio Dell, the two North Coast towns closest to the epicenter of Thursday’s 6.6 magnitude earthquake, to assess the impact.

Lt. Clint Michel of the Ferndale Volunteer Fire Department reported the damage in Ferndale is “very minimal.” By 12:30 p.m., firefighters had found no structural damage to the town’s buildings, though some homes experienced items being tossed about during the quake. Michel added that fire personnel encountered a lot of “scared people” in the immediate aftermath.

Rio Dell Fire Department Assistant Chief Ryan Heussler gave a similar update, saying, “We’ve got units out, and I’m pleased to report that damage is minimal. It was a rapid assessment, and everything looks pretty good. We’re happy to report that.” He noted that a few stores were closed, “because there might be a mess inside.”

12:30 p.m.

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Operations at San Francisco's Alcatraz Island were briefly suspended Thursday after the National Weather Service issued a tsunami warning for much of Northern California.

The warning, which was sent to phones and appeared on web browsers, came after a preliminary magnitude 7.0 earthquake hit some 60 miles off Ferndale in Humboldt County. The warning was canceled roughly an hour later after the weather service said the tsunami threat had passed.

According to Cornelius Geary, a spokesperson for Alcatraz City Cruises, the roughly 200 guests on the island when the alert hit were told to shelter in place until the threat had passed. As of Thursday afternoon, operations had resumed and guests were able to take a ferry back to Pier 33.

According to the United States Geological Survey, the earthquake struck at a depth of roughly 10 kilometers at 10:44 a.m. No damage or injuries were immediately reported, the USGS said.

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12:15 p.m.

Emergency officials in San Francisco used trucks and loudspeakers to warn residents to leave San Francisco’s beaches Thursday following a tsunami warning. At Ocean Beach, emergency personnel drove on both the Great Highway and the beach telling residents to head to higher ground. Justin Schorr, a rescue captain for the San Francisco Fire Department, said that anywhere within one mile of the coastline was considered at risk for a tsunami.

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The National Weather Service later issued an update at approximately noon that “THERE IS NO LONGER A TSUNAMI THREAT FROM THIS EARTHQUAKE.”

Residents had congregated at the beach throughout the tsunami warning despite officials urging them to leave. Schorr said prior to the warning being lifted that people should head to higher ground by following “the predetermined evacuation routes that are posted in communities.”

“Please stay away from the coastline, there is nothing to see at the beach,” Schorr told SFGATE.

10:57 a.m.

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A preliminary magnitude 7.0 earthquake hit some 60 miles off Ferndale in Humboldt County late Thursday morning, according to the United States Geological Survey. In the aftermath of the shaking, the National Weather Service issued a tsunami warning, urging Californians to "get away from coastal waters."

"Tsunami warnings mean that a tsunami with significant inundation is expected or occurring," the California Office of Emergency Services said "Warnings indicate that widespread dangerous coastal flooding accompanied by powerful currents are possible and may continue for several hours after the initial wave arrival."

The warning extends from Davenport, Calif., about 10 miles northwest of Santa Cruz, to the Douglas-Lane county line in Oregon, about 10 miles southwest of Florence.

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The first waves are expected to arrive at 12:10 p.m. for San Francisco Bay Area, Karleisa Rogacheski, a meteorologist for the weather service told SFGATE. In areas farther north, such as Fort Bragg, the waves could come sooner, she said. Rogacheski said the weather service is still assessing the wave heights and severity, but advised people to stay away from the water. She said the warning is different from an advisory, because a warning indicates that "impacts are expected to occur."

"Stay away from the waters. Don't go out looking for the tsunami," she said. "We don't want people to get caught off in stuff offshore."

The San Francisco Department of Emergency Management advised those near the coast to move to higher ground or inland areas until officials say it's safe to return. "A series of powerful waves and strong currents may impact coasts near you. You are in danger," the agency said in a social media post.

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Once the waves hit the area, Rogacheski said the weather service will have more updates.

The earthquake struck at a depth of about 10 kilometers at approximately 10:44 a.m. A series of aftershocks have also rattled far Northern California after the initial 7.0 magnitude quake. No damage or injuries were immediately reported, the USGS said. BART temporarily stopped all trains from using the Transbay Tube but resumed regular service shortly before noon.