Washington state's tsunami risks only half-mapped

(Credit: KING)
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Washington state's tsunami risks are only half-mapped, and more money is needed to finish the job.

The Washington Department of Natural Resources is asking for $543,200 over the next two years to hire three additional staff members to finish mapping the state's tsunami risks. Beyond that, another $493,200 is needed each year to maintain the mapping project as new fault lines are discovered, and the state's tsunami risks keep evolving. 

There are a number of tsunami inundation maps for more populated areas along Washington's outer and north coasts. These include Bellingham and other exposed places where a tsunami generated along the Cascadia Subduction Zone near our continental shelf, or other locations around the Pacific Rim, could reach.   

But there's also believed to be a tsunami risk from the Seattle Fault, which could envelop lowlands in Seattle such as Harbor Island and SODO. Everett and other low-lying lands around Puget Sound are also considered vulnerable.  

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"We need to get full coverage for the entire state," Corina Forson, the state's chief hazard geologist, said.

She says while some areas were mapped with federal money at least a decade ago, those scenarios didn't necessarily incorporate worst-case scenarios. Those scenarios include a very large tsunami every 2,500 years. They also include tsunamis waves -- still 100 feet or so high -- from more typical earthquakes off our coast. Those can happen every 250 to 500 years. 

It so happens January 26, 1700, was our last major earthquake and tsunami -- 318 years ago, Friday. Scientists say the next one could come anytime. Nobody can say. 

Washington found itself on a tsunami watch on Tuesday after a 7.9 magnitude earthquake in the Gulf of Alaska. Because of the nature of the earthquake on a strike-slip fault, only a tiny tsunami was generated.