Study examines doomsday tsunami scenario in Malibu

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This map produced by the USGS shows a potential flooding zone in Malibu’s Civic Center if a 9.1-magnitude earthquake were to strike off of Alaska and cause a tsunami along the California coast. 

A major tsunami hitting the California coast would inundate large portions of the Southland and wipe out homes along Malibu’s coast, a recent study from the United States Geological Survey (USGS) found. 

The study attempted to predict the hypothetical repercussions of a tsunami if a 9.1-magnitude earthquake were to strike offshore from Alaska’s peninsula, sending massive waves along the west coast as far as San Diego. It found that state and local governments are underprepared for a major tsunami disaster. 

“Stretches where houses are very, very close to the beachfront would be inundated,” said Charles Real, a supervising engineering geologist for California Geological Survey who worked on the study. 

The science behind the study was simulated after the 2011 tsunami that struck Tohoku, Japan after a 9.0 offshore quake. 

A map of the potentially affected areas shows tsunami flooding could inundate Malibu beaches and homes along Pacific Coast Highway, including Broad Beach, Malibu Road, the Malibu Colony, the Adamson House, Malibu Pier and structures along the mouth of the Malibu Creek and Surfrider Beach where the Malibu Lagoon is located. The hypothetical scenario does not envision flooding jumping north of Pacific Coast Highway, except in the Malibu Lagoon, Zuma Lagoon and Trancas Market Center area. 

While the subject matter grabs attention, Brad Davis, the City of Malibu emergency services coordinator, downplayed the report’s scenario in Malibu specifically. 

“[In Malibu], because of the geography of the area and the undersea topography, we have been assured that our risk of tsunami is not as high risk as it is in other places,” Davis said. “…We really don’t feel that that is a severe threat here.” 

Most of the study concerns the effect on the entire coastline of California. Researchers estimate a tsunami of the 9.1-magnitude could cause up to $3.4 billion in collective damage to California’s coastal properties, ports and marinas. 

By virtue of its location on the coast, Real said Malibu would always be vulnerable to a tsunami. 

“You cannot economically protect a home from that kind of damage when you’re on a coast like Malibu,” he said. 

Real recommended residents pack 3-4 days worth of supplies for possible evacuations. 

“Be prepared to possibly be out of your home for a while,” he said.

Otherwise, local governments and safety agencies should be the ones the public turns to in times of disaster. 

“In most cases, looking at the potential for life safety, it really falls in the domain of the emergency response agencies,” Real said. “If you’re in homes that were built years ago, then you really have to rely on a good emergency response to help.” 

Public outreach has lagged in the area of tsunami preparedness, the USGS found, and recommended local agencies improve education efforts in coastal communities. 

“There is an overarching challenge to reach the general public…and to adequately train and prepare the multiple levels and types of governments to mitigate tsunami hazards and manage the impacts and consequences of this scenario and other potential tsunamis that threaten California,” the report stated. 

In the off chance a tsunami does affect this town of 13,000, Davis said beachfront owners should educate themselves. 

“If we did have a serious earthquake and you live close to sea and you see water pulling away [from shore], then you should be prepared to evacuate,” he said. “Just like if you live in an area with high wildfire danger, you need to know what the danger signs are.” 

To read the report, visit pubs.usgs.gov/of/2013/1170/a/. A map of potential tsunami flood zones in Malibu can be viewed at quake.ca.gov/gmaps/tsunami/safrr.htm.