How likely will a tsunami hit Malibu, Long Beach, or other parts of Southern California?

Written by Amy Ta, produced by Angie Perrin

Huge stretches of LA County’s coast could be at a big risk for tsunami damage, and the most vulnerable areas include Marina del Rey, Long Beach, Venice, Santa Monica, and Malibu. That’s all according to new maps released Monday by the California Geological Survey.

A tsunami is a sudden rise in sea level, which is usually triggered by a large earthquake that alters the shape of the seafloor, explains Lucy Jones, seismologist and author of “The Big Ones: How Natural Disasters Have Shaped Us (and What We Can Do About Them).” 

She assures that the likelihood of a tsunami hitting Southern California is relatively low “because our faults are mostly horizontal moving,” and the risk is higher in the Pacific Northwest, Japan and Chile.

“Malibu, the only thing at risk is really the beach because you're above 20 feet very, very quickly. Venice and Long Beach and the marina are all places where it stays close to sea level for a greater distance inland. But even so, none of the expected tsunamis make it past Lincoln Boulevard.”

She points out that a tsunami can come in from elsewhere, which is mostly what these new maps are showing, and as long as people who live in vulnerable areas evacuate when they get a warning, the loss of life is minimal. 

Jones says that for Southern California, tsunamis are much lower risk than other threats, such as fires, landslides, earthquakes, and floods. 

“We had a huge flood in 1861-62 that put most of the LA basin and most of Orange County underwater. It's more likely the water is going to come from our mountains than from the ocean on the long run.”

The big thing Jones wants to point out is that cliffs comprise 77% of California’s coastline. “That means that sea level rise doesn't matter.”

She advises that if you do feel strong shaking at the beach, leave the beach. “An earthquake could be triggering a landslide and that could cause a very local tsunami. I mean, the downside is you lose a day at the beach, and the upside could be your life.”