A powerful earthquake struck 30 miles off the California coast on Thursday morninglodibet, prompting emergency tsunami alerts to buzz on more than half a million cellphones and sending cans and bottles crashing to the floors of grocery stores in the rural communities closest to the epicenter.

Yet despite the earthquake’s intensity — a magnitude of 7.0, according to the U.S. Geological Survey — the shaking caused little damage because of its remote epicenter in the Pacific Ocean, 200 miles north of San Francisco Bay. The tsunami warnings were canceled about an hour after they were issued.

Shake intensity Note: Map shows the area with a shake intensity of 3 or greater, which U.S.G.S. defines as “weak,” though the earthquake may be felt outside the areas shown. Source: U.S.G.S. By William B. Davis and John Keefe

In Petrolia, southeast of the quake’s epicenter, Margit Cook, 73, a clerk at the Petrolia General Store, said it was one of the largest earthquakes she had experienced in the 53 years she has spent in the remote Northern California community.

“It just started rolling real slow and got bigger and bigger and then hit,” she said. “And it hit real hard. I just kind of stood there and watched my refrigerator walk across my kitchen floor.”

At one point, more than than 10,000 customers had lost power in Humboldt County, according to the site poweroutage.us. More than a dozen aftershocks struck after the initial quake, all off the Northern California coast.

We are having trouble retrieving the article content.

Please enable JavaScript in your browser settings.

Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.

Thank you for your patience while we verify access.

Already a subscriber? Log in.

Want all of The Times? Subscribe.lodibet

• lodibet
• quake
• rattles
• Northern
• California