California Tsunami Would Have Costly Aftermath

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The fearsome aftermath of a tsunami striking California might cost at least $3.4 billion to repair, but neither of the state's nuclear power plants would be damaged, suggests a new analysis that could help officials and the public prepare for a tsunami and reduce risks before any such disasters happen.

The Washington state coastline is the most tsunami-prone area in the United States.
DCI

Ever since the 2004 Indian Ocean earthquake and tsunami claimed about 250,000 lives, scientists have investigated the risks a tsunami crashing against the United Statesmight have. The fact the 2011 Tohoku-Oki earthquake and tsunami in Japan killed another 20,000 or so people and triggered a nuclear disaster further underscored the importance of such research, especially since the deadly wave also swept through California, albeit at a lesser strength, and caused $50 million to $100 million of damage.

A map of the California coast in the City of Long Beach showing areas predicted to be inundated (in red) by the SAFRR Tsunami scenario. These include the Long Beach Convention Center and many retail businesses.
SAFRR Tsunami Scenario

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Giant earthquakes can occur off the Alaskan coast, where the tectonic plate underlying the Pacific Ocean is diving underneath the continental plate underneath North America — in fact, the second-largest recorded earthquake in history was a magnitude-9.2 at this zone in 1964. The result could be a tsunami reaching down to California.

Six independent teams of scientists modeled a tsunami created by a magnitude-9.1 earthquake offshore the Alaskan peninsula as if it happened at nearly noon Pacific Time on Thursday, March 27, 2014, the 50th anniversary of the 1964 Alaska quake and tsunami. The federal and state researchers wanted to see the likely dangers such a tsunami would pose for California. [Waves of Destruction: History's Biggest Tsunamis]

"We created a scenario of what a plausible bad tsunami would be for California," researcher Lucy Jones, U.S. Geological Survey Science Advisor for Risk Reduction, told LiveScience.

NEWS: Calculating California’s Tsunami Risk

Tsunami hazard

According to the model, it would take nearly six hours for the tsunami to crash into San Diego. After accounting for the amount of time needed to confirm the magnitude of any earthquake in Alaska, see whether it generated a tsunami, and calculate when it might hit, Southern California might have 3.5 hours of warning that a tsunami was on the way, while Northern California might only get two hours of warning, Jones said.

"The good news is that three-quarters of California's coastline is cliffs, and thus immune to the harsher and more devastating impacts tsunamis could pose," Jones said in a statement. "The bad news is that the one-quarter at risk is some of the most economically valuable property in California."

The bent shape of the California coast would lead the height of the tsunami approaching from the north to be significantly reduced in Southern California. As such, the tsunami hazard from this scenario is generally less in Southern California than elsewhere along the state's coast, although some areas of Southern California may be more vulnerable because they are low in elevation or have more people and maritime assets concentrated on the coast.