Tsunami Warning Rattles West Coast

An earthquake with a preliminary magnitude of 7.0 struck Tuesday off the coast of Northern California shortly before 8 p.m., prompting authorities to issue rolling tsunami warnings for coastal areas from Alaska to the Mexican border.

There were no immediate reports of significant damage or injuries in communities closest to the epicenter, including Crescent City, the site of a 1964 tsunami that killed 11 people and washed away 29 city blocks.

Crescent City leaders immediately sounded warning sirens Tuesday night, signaling the 4,000 or so people in low-lying areas to evacuate according to the city’s tsunami emergency plan.

Throughout coastal California, emergency workers descended on beaches to warn of possible danger, and confusion lingered after officials called off the warning about 9 p.m.

In San Diego, firefighters in beach areas and night-shift lifeguards urged people on beaches and boardwalks to move inland “as a precaution,” but no mandatory evacuations were ordered.

In Huntington Beach, authorities struggled with more than 200 calls from the public as well as conflicting reports over a Police Department teletype machine saying there was a tsunami warning and then there was not.

“It just started raining phone calls,” said Huntington Beach Police Watch Cmdr. Sgt. Craig Bryant. “They wanted to know what to do, where to go, what to do with the dog.... It was very hectic.”

In Seal Beach, police officials said they planned to do a “reverse 911,” automatically calling citizens to update them on the warning. If necessary, the calls could have warned people near the beach to seek higher ground, said Sgt. Joe Miller.

The quake struck in a seismically active area under the Pacific Ocean known as the Juan de Fuca plate.

Caltech seismologist Kate Hutton said the tsunami warning came from the West Coast and Alaska Tsunami Warning Network in Palmer, Alaska, and was issued as a precaution.

“I’m not sure about their thinking, but probably the reason they issued it is because it’s so close to shore,” she said. “There was no time. They didn’t take any chances.”

Within a few hours of the earthquake, she said, scientists studying preliminary data believed the quake -- despite its size -- had created little tsunami danger. That’s because the earth had moved in what is known as a quake “strike slip,” meaning fault surfaces had moved horizontally past each other, leaving behind no change in the level of the ocean floor.

In an average year, the world experiences about 10 magnitude 7.0 temblors, Hutton said.

Tuesday’s quake interested seismologists studying so-called trigger earthquakes because it came after several significant quakes struck in recent days. On Sunday, a 5.2 magnitude quake hit 20 miles south of Palm Springs in Anza. On Monday night, a 7.8 magnitude quake hit Chile, killing at least 11 people. On Tuesday morning, a magnitude 6.8 quake struck the Aleutian Islands, both preceded and followed by smaller quakes.

“One of the things that is very exciting in seismology now is trigger earthquakes,” Hutton said. “The seismic waves shake loose earthquakes in neighboring areas, or not-so-neighboring areas.”

Hutton said, however, that given its relatively small size, it was unlikely the Anza quake was a true trigger.

Officials from the tsunami warning center could not be reached for comment. But Hutton said she believed this was the first large-scale tsunami warning in California in almost two decades. In 1986, a tsunami warning was issued after a 7.7 magnitude quake struck Adak, Alaska.

While Tuesday’s tsunami warning was issued for the West Coast, it was communities in Humboldt and Del Norte counties on the far north edge of California where officials were most concerned because of their proximity to the epicenter.

The potential danger may have seemed most acute in Crescent City, a coastal town of 7,500 residents about 20 miles from the Oregon border. Memories of the 1964 tsunami have never faded, and motels there still post fliers telling visitors how to survive the hazard. That deadly wave had traveled more than 500 mph from its origin off the coast of Valdez, Alaska, created by a massive 9.2 magnitude temblor, even stronger than last year’s Indian Ocean tsunami. Before striking the town, the wave had killed more than 100 people in Alaska, four people on the Oregon coast and caused millions of dollars in damage.

In the aftermath of the Dec. 26 Indian Ocean tsunami -- a wave that killed more than 175,000 and left more than 100,000 missing -- Crescent City was the only town in California declared “tsunami ready” by the federal government.

On Tuesday night, its residents described tense moments before local authorities said the danger of a giant wave striking had passed.

“We’re leaving now; the tsunami is coming,” said Arturo Marquez, who works in the kitchen at Northwoods Restaurant in Crescent City.

He said there was no damage to the restaurant. Then police came telling everyone to leave. Marquez said he and others planned to get as far from the coast as possible.

Nearby, David McKee and his wife, Alison, of Madison, Wis., were eating dinner at the Beachcomber restaurant.

“We felt our booth rocking. We thought someone was rocking it,” David McKee said. They had almost finished when “one of the owners ran in and said there was a tidal wave warning.”

Not sure what to do, the couple went next door to the Crescent Beach Motel, packed and drove up Highway 101. Everyone was allowed to return after spotters positioned on cliffs above the ocean saw no signs of rising water. The McKees -- who had heard the all-clear on their car radio -- came back and paid for dinner.

“We are going to stay. If someone pounds on our door, we’ll get up and go,” he said, adding that his wife planned to sleep in her clothes, just in case.

In the town of Trinidad, residents took the warnings seriously.

About 30 customers were at the Seascape Restaurant on the Trinidad Pier when word of possible danger came shortly before 8:30 p.m. Manager Ruth Ruth told customers they could finish their meals but should eat quickly. Within minutes, everyone had followed the evacuation plan.

“We did not charge anybody anything at that point,” Ruth said, noting that it was the first evacuation in her 17 years at the restaurant.

One couple, though, vowed to return for their chowder.

“We gave them fresh chowder, of course,” Ruth said.

Times staff writers John M. Glionna, Jean Guccione, David Haldane, Peter Y. Hong, Monte Morin, Tony Perry, Valerie Reitman, Joel Rubin and Kenneth R. Weiss contributed to this report.