(NewsNation) — An earthquake felt across Northern California Thursday morning initially appeared to cause minor damage across the affected areas.
The quake struck late morning with a preliminary magnitude of 6.6, according to the United States Geological Survey (USGS). However, the USGS later revised that magnitude to 7.0 and then to 7.3.
At least 5.3 million people in California were under a tsunami warning after the earthquake, the USGS said in a yellow alert, which predicted localized but minimal damage.
The quake struck in the Pacific Ocean about 5 1/2 miles west of Ferndale, a small city in coastal Humboldt County, and was followed by smaller aftershocks that were felt as far south as San Francisco, where residents felt a rolling motion for several seconds.
Minor damage has been reported as of Thursday afternoon.
Local news outlets and reporters posted videos on social media showing products knocked off shelves and scattered on the floors of grocery stores.
The door of a local Ferndale hotel appeared to have torn off, and several bottles were shattered over the hotel’s bar floor. The hotel owners did not immediately return a phone call from NewsNation.
More than 1.3 million people lived close enough to the quake that they could have felt it, the USGS estimated. The agency is forecasting aftershocks registering 3.0 or greater could occur throughout the upcoming week.
California Gov. Gavin Newsom activated the State Operations Center shortly after the hit to coordinate information and response efforts with state and local first responders.
The San Francisco Bay Area Rapid Transit District, known as BART, had stopped traffic in all directions through the underwater tunnel between San Francisco and Oakland.
The San Francisco Zoo announced it was closing due to a national weather emergency and tsunami warning. Guests were evacuated and animals secured as staff moved to higher ground.
The earthquake was the largest to hit Northern California since the 1992 Cape Mendocino earthquake, and it also had an epicenter in Humboldt County.
The Associated Press contributed to this story.
