If a monster earthquake struck off Alaska's coast, tsunami waves would rush toward California, swamping the nation's largest port complex and causing major economic damage, according to a hypothetical scenario released Wednesday by the U.S. Geological Survey and others to help emergency planners prepare.
“There is strong reason to believe that California faces a tsunami threat that could realistically cause billions of dollars in losses and, although we have not discussed it here, substantial loss of life,” according to the Science Application for Risk Reduction (SAFRR) Tsunami Scenario.
Tsunamis are a rare but real threat in California.
After the 2011 Japan disaster, tsunami waves surged across the Pacific and damaged the Northern California commercial fishing village of Crescent City.
The bulk of the California damage from the 8.9-magnitude Japanese quake – estimated at $50 million – was reported in Crescent City and Santa Cruz.
Scientists say a closer offshore quake would create more havoc, flooding the ports of Los Angeles and Long Beach, forcing coastal communities to evacuate and destroying boats and small craft.
The report considers a "hypothetical but realistic " magnitude-9.1 quake offshore of the Alaskan Peninsula -- some 3,100 miles away.
The first wave could arrive at the ports within 3 ½ hours of a tsunami warning, according to the report. Experts said fuel stored in ports and marinas likely would ignite fires.
Because of California’s shape and geography (more than half the coastline is cliff), the tsunami hazard in this scenario would be generally less in Southern California than elsewhere along the coast.
However, low-lying portions of southern Los Angeles and northern Orange Counties are among the cities in the inundation area.
In the worst case scenario, some 169,000 residents and employees would be in those at-risk zones and ordered to evacuate.
More than 260,000 tourists would be expected on California’s beaches and in parks on the day of the scenario, the report finds. That figure swells to more than 1 million tourists in the summer months.
The tsunami scenario is similar to a quake exercise released several years ago designed to prepare for a big one on the San Andreas Fault.
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