SAN FRANCISCO – A magnitude 7.0 earthquake struck Northern California in Humboldt County, according to the USGS.

The epicenter is offshore near Petrolia in Humboldt County, the USGS said.

Additionally, a tsunami warning that had been issued for coastal areas in California and Oregon, including San Francisco, was lifted just before noon local time.

“The tsunami warning has been lifted for coastal areas of California and Oregon,” the National Tsunami Warning Center wrote on X. “There is currently no tsunami threat for this area.”

At least 5.3 million people in California were affected by the tsunami warning, the US Geological Survey said in a yellow warning that predicted localized but minimal damage.

According to the USGS, Thursday’s earthquake was “primarily a strike-slip earthquake,” which is less likely to trigger a tsunami because the Earth’s tectonic plates moved more horizontally than vertically.

The warning was in effect from Davenport, California, to Douglas/Lane Line Oregon, the National Tsunami Warning Center said.

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The earthquake was initially reported as a magnitude 6.6 quake, but was then upgraded by the USGS.

According to the National Tsunami Warning Center, it was reported at 10:44 a.m. local time.

According to the USGS, additional earthquakes have been reported in the region, including a magnitude 5.0 earthquake near Ferndale and a magnitude 4.2 earthquake near Petrolia.

Shake warnings in the USGS Earthquake Early Warning System were transmitted as far north as Lincoln City, Oregon, and as far south as Salinas, California, the agency said.

“The system activated and ran as planned. “I’m still trying to figure out how many warnings people received,” the USGS said.

There were no immediate reports of damage.

The earthquake was felt as far south as San Francisco, where residents felt a rolling motion for several seconds. As of 12:36 p.m. Thursday, at least 35 aftershocks had been recorded by the USGS in Northern California

The strongest aftershock was recorded at 5.0.

The San Francisco Zoo said guests have been evacuated and animals and staff are moving to higher ground after a tsunami warning was issued due to the Humboldt County quake.

The Bay Area’s BART transportation system is experiencing significant delays due to the quake. There is no train service through the underwater Transbay Tube.

California Gov. Gavin Newsom said the state’s emergency services officials were “actively responding to the earthquakes this morning in Northern California.”

“Californians should follow the guidance of local emergency responders,” he said on social media.

As for aftershocks, there is currently a 5% chance of a magnitude 6 or larger earthquake occurring in the next week and a 34% chance of a magnitude 5 quake occurring during that period, according to the USGS.

The USGS estimates that more than 1.3 million people lived close enough to the quake that they could have felt it.

Phones in the Santa Cruz area buzzed with a tsunami warning from the National Weather Service that said: “A series of strong waves and strong currents could impact shores near you. You are in danger. Stay away from coastal waters. Get to high ground” or stay inland away from the coast now until local authorities say it is safe to return.

As for aftershocks, there is currently a 5% chance of a magnitude 6 or larger earthquake occurring in the next week and a 34% chance of a magnitude 5 quake occurring during that period, according to the USGS.

USGS officials advised people to prepare for aftershocks in the coming days and weeks.

This is breaking news. Check back for updates.

ABC News and the Associated Press contributed to this report.