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1. 

   Comment by B.N.Dunning on 18 September 2008:

   Gordon: I loved your book (as have my friends)and I do have a question re the possibilitiy of a Tsunamin hitting the southern coast of California.

   When the tsunami hit in 2005, the so-called experts said that our coastline was not subject to a tsunami and we weren’t to worry. Is that a fact, or sugar-coated to appease us?

   barbara
2. 

   Comment by Gordon on 4 October 2008:

   Barbara: According to a report by the California Seismic Safety Commission, California is at risk from both local and distant tsunamis. In the last 150 years, over 80 tsunami events have occurred along the California coast, most of them so small they were measurable only by tidal gauge variations. However, eleven were large enough to cause damage. The two largest were the 1960 Chilean undersea earthquake that sent a major tsunami spreading throughout the Pacific Basin, causing over $1,000,000 in damage to ports and harbors from San Diego to the Oregon border. And the Great Alaska Earthquake of 1964 that sent a tsunami rolling down the coastlines of Canada, Washington, Oregon, and California. A wave 21 feet high struck Crescent City, taking 12 lives and flooding a large part of the city.
   Two-thirds of California’s tsunamis come from distant sources, mostly undersea earthquakes in other parts of the Pacific Basin. The balance are local events and usually small. The only significant local tsunami was caused by the Point Arguello earthquake in 1927. It produced a 7-foot wave that impacted areas near the epicenter.
   Although a major tsunami hitting Southern California is a distinct possibility, the odds of one happening are low. The nearest location where a major undersea earthquake might occur is the Cascadia Subduction Zone that runs along the seafloor off Oregon and Washington, 800 miles north of Southern California beaches. It has been 300 years since the last major undersea earthquake took place on the Cascadia, causing sudden seafloor deformation and spawning a tsunami comparable to the one that hit Sumatra in 2004. If that were to happen today, it is highly possible that a 15 to 20 foot tsunami would sweep down the coast and strike coastal communities from Santa Barbara to San Diego.
   There are a series of fault lines in the Santa Barbara Channel that have produced earthquakes of magnitude 6.0 and under, but none have caused measurable tsunamis. The continental shelf is not too far offshore, and undersea landslides on the edge of the shelf could produce a localized tsunami, but no such event that I am aware of has been recorded in the Southern California area.
   Southern California is not as likely to experience a damaging tsunami as those areas closer to major subduction zones, but the area is considered at risk from both distant and local tsunamis. In all probability, the Alaska and Pacific Coast Tsunami Warning Center will issue a tsunami alert in time to evacuate before a major tsunami from a distant source arrives.

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