Tsunami Study Sounds Dire Warning for West Coast

Thursday, September 05, 2013

The ports of Los Angeles and Long Beach would lie in ruins. Oakland’s airport would be underwater. And 750,000 people would need to be quickly evacuated, including tourists and beach visitors.

That scenario accompanies a  “hypothetical but plausible tsunami” that could rise up after a 9.1 earthquake in Alaska, according to a joint study (pdf) by the U.S. Geological Survey (USGS) and California state agencies.

The report estimates that repair costs would top $3.5 billion but that the damage to the economy would nearly double that, at $6 billion. Most of the economic damage ($4.3  billion) would come from loss of the ports, which could be reduced by 80-90% if “resilience strategies” are put in place ahead of time. Considering the state’s track record on long-range disaster planning, it might be prudent to bank on the higher figure.

There would be fires at port and marina sites where petrochemicals and fuel are plentiful, exacerbated by electrical problems. Runoff from agricultural fields would spread pesticides, herbicides and fertilizers, contaminating near-shore marine environments. Because three-fourths of the coast is cliffs, much of the state would escape devastation. “The bad news is that the one-quarter at risk is some of the most economically valuable property in California,” according to Lucy Jones, who is the USGS science advisor for risk reduction and leads the project that did the study.

The researchers admit that they don’t have a lot of empirical information to build their study around. There have been few devastating tsunamis in modern times. That’s one of the reasons there isn’t much advanced planning for dealing with a tsunami disaster.

Six independent teams of researchers created computer models to analyze the effect of the earthquake and aftermath. The initial waves, at multiple locations, would be the largest at a few locations like Monterey Bay and Morro Bay. But for the most part, the biggest waves would arrive hours later. Sometimes seven hours later. That would especially be the case in Southern California. All of this would rely, to some extent, on how the earthquake coincided with high tides.    

There would be winners and losers from a disaster of that magnitude. Industries dependant on trade would suffer. Service industries related to marinas might gain. The fishing sector would suffer an interruption, but fishermen who survived might prosper from less competition. Agriculture would suffer from crop losses in low-lying areas. Rail transportation would be disrupted.   

The report, which by its very nature tends toward a doomsday view of things, also sounds this note of optimism: “Reconstruction that would be partially funded by disaster funds and insurance (financial forms of resilience) would eventually provide a stimulus to the local and State economies.”

So mark your calendars for March 27, 2014, at 11:57 a.m. PDT because that was the date used by researchers to simulate the disaster. It’s the 50th anniversary of the 1964 Alaska earthquake and tsunami.

–Ken Broder


To Learn More:

Report: Tsunami Would Swamp California's Economy (by Alicia Chang, Associated Press)

Study: Tsunami Could Slam San Diego (by Gary Robbins, U-T San Diego)

Experts Team Up on Tsunami Resilience in California (U.S. Geological Survey)

The SAFRR (Science Application for Risk Reduction) Tsunami Scenario (U.S. Geological Survey) (pdf)

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