A tsunami advisory has been issued for the entire West Coast after a massive earthquake near Russia.
Alexandra Hootnick/Special to the Chronicle 2022
California and the entire West Coast from Washington to the Mexico border were under a tsunami advisory after an 8.8 quake rocked Russia earlier in the day. The estimated arrival time for San Francisco would be after midnight Pacific time.
A tsunami advisory is issued when a tsunami with the potential to generate strong currents or waves dangerous to those in or very near the water is imminent, expected or occurring. An advisory indicates that the tsunami may be hazardous to swimmers, boats and coastal structures. People are advised to move off the beach and out of harbors and marinas.
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The California Geological Survey has created maps showing hazard zones along the entire coast where water might inundate the shoreline during a tsunami. Below is an interactive version of the map that allows people to check if they live or work in a tsunami zone, and where to escape it.
“What we’re depicting with that line is where we anticipate the tsunami to stop and not affect you if you were at a higher elevation,” said Jeremy Lancaster, a geologist at the California Geological Survey.
The hazard zones are based on a number of possible worst-case scenarios, such as if a huge 9.3-magnitude underwater earthquake near Alaska’s Aleutian Islands caused a large tsunami, an event expected to take place only about once every 1,000 years. They also take into account the risk of a tsunami caused by earthquakes closer to home, such as in the Mendocino Fault, where Thursday’s 2024 Offshore Cape Mendocino California Earthquake took place.
When a warning is sent out and you don’t have a map available, look for tsunami hazard evacuation signs. When all else fails, go at least a mile inland from harbors, beaches, lagoons, bays and any other low-lying coastal areas, Lancaster said.
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Fortunately, tsunamis that are likely to hit the Bay Area often come with some warning time. Though timing varies, it likely would take about an hour for a tsunami to travel from the Mendocino Triple Junction to the Bay Area, said Behringer. And it would take about five hours for a tsunami caused by a huge Alaskan earthquake to reach the Bay Area.
Earthquakes closer to and even farther from the Bay Area can also cause tsunamis, such as Japan’s in 2011, which killed one person in California and caused $100 million in damage in the state. The tsunami following the 2022 underwater volcanic eruption in the Pacific Kingdom of Tonga caused damage in Santa Cruz harbor, and the 1989 Loma Prieta earthquake sparked an underwater landslide in Monterey Bay that produced a small tsunami.
Jacob Roper, a spokesperson for the California Department of Conservation, noted that the hazard maps “are not emergency response tools,” and people should look for direction to the California Office of Emergency Services.
July 29, 2025
