California Geological Survey updates tsunami hazard map for 7 counties

SACRAMENTO, Calif. — The California Geological Survey has released updated tsunami hazard maps for seven counties to help users determine if they are in areas at risk of flooding and for planning.

The revised interactive maps released Friday cover San Diego, Santa Cruz, Ventura, Marin, Sonoma, Solano and Napa counties.

The new maps reflect new data and improved computer modeling since a previous series of maps was published in 2009, as well as threats from tsunamis originating far away and locally, the Geological Survey said in a news release.

In one example of the updates, new modeling for Santa Cruz County shows that a subduction zone earthquake off the Aleutian Islands could trigger a tsunami 18-25 feet (5.5-7.6 meters) above the Santa Cruz Boardwalk, more than double the the height proposed in 2009, the agency said.

The Geological Survey said California’s coasts have been hit by more than 150 tsunamis since 1800, and while most were minor, some have been significantly destructive and deadly.

On March 28, 1964, a tsunami triggered by a powerful earthquake in Alaska struck Crescent City, California hours later. A large part of the business district was razed to the ground and a dozen people were killed.

More recently, a tsunami from a 2011 Japan earthquake caused about $100 million in damage to ports and harbors in California, and sea levels from last January’s volcanic eruption in Tonga caused about $10 million in damage to ports in Santa Cruz and Ventura counties.

The California Geological Survey is part of the state’s Department of Conservation.

Copyright © 2022 by The Associated Press. All rights reserved.

Leave a Comment