For generations, the possibility of another devastating earthquake has lingered in the minds of Californians, who are remarkably familiar with seismological terms and regularly prepare for the next “Big One.”

But on Thursday, they were met with something that felt a little more far-fetched: a tsunami warning along a vast stretch of the Northern California coast. It brought fear and confusion to hundreds of miles of coastline, from the San Francisco Bay Area to Oregon — and even more than a dozen miles inland, in some cases.

The tsunami warning was spawned by an earthquake in the Pacific Ocean and was canceled a little more than an hour after it was issued. But the sudden and dire warnings, which urged people to move immediately to higher ground, stirred a panic. Many headed for the hills.

Jon Ward, an architect who was renting a beachfront home on Stinson Beach, north of San Francisco, said he was initially skeptical of the tsunami warning that blared on his cellphone. But then he reconsidered, and called his wife, who was on a walk, to tell her to hurry back.

They drove into the Marin Hills toward Mount Tamalpais and planned to park at the first car turnout. One problem: turnout after turnout was packed with vehicles.

“Everybody else had the same idea,” said Mr. Ward, 66. Once they found a space, they watched as other evacuees lined up at turnouts along Highway 1 until the tsunami warning was canceled.