EVERETT – Could it happen here?
Is Snohomish County, with its western edge made up of beaches and bluffs overlooking Puget Sound, at risk of one day being inundated by a massive tsunami similar to the one that killed more than 22,500 people in Asia on Sunday?
The answer is good news and bad news, said Lee Hazlewood, homeland security manager with the Snohomish County Department of Emergency Management.
A tsunami spawned by the 1964 Alaskan earthquake caused some damage on the Washington coast. Experts believe it is unlikely that a wave kicked up by an earthquake beneath the Pacific Ocean would travel far enough into Puget Sound to cause much damage along local beaches, Hazlewood said.
People living here are at risk, however, from waves caused by earthquakes or landslides into Puget Sound.
Scientists have found evidence of soil deposited by a tsunami at Cultus Bay on the south end of Whidbey Island. Deaths linked to that type of disaster also are part of the community’s oral history.
Localized tsunamis, sometimes called seiche (pronounced sigh-shh), are an identified risk to people who live along enclosed or partially enclosed bodies of water, such as Puget Sound, Hazlewood said.
Seiche are produced when a basin containing water is shaken, causing waves to form. The process is similar, on a giant scale, to what happens when liquid sloshes over the lip of a bucket when it is given a sharp jolt. Waves also can be formed when earth slides into a basin, kicking up a wave.
Members of the Tulalip Tribes tell of a horrific slide in the 1820s or 1830s that buried a summer village on the south end of Camano Island. More than 100 people died in the slide at Camano Head, which is said to have sent a wave up over much of nearby Hat Island, drowning still more.
Some historians believe the disaster was triggered by a powerful earthquake, but that was decades before written records were kept of seismic activity in the area.
When a tsunami threatens, there is sometimes an opportunity to evacuate areas where the wave is predicted to make landfall. That isn’t the case with a seiche, which can make it particularly deadly, Hazlewood said.
“The earthquake happens here and the tidal waves occurs,” he said.
Reporter Scott North: 425-339-3431 or north@heraldnet.com.
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