Tsunami safe havens explained, final report due end of December

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SEAVIEW - Where do you flee when several walls of seawater are barreling toward our nearly pancake-flat sand spit? You build artificial high ground in advance.

The University of Washington Hazards Mitigation Institute along with state, local and tribal emergency management officials shared information regarding tsunami vertical evacuation opportunities in the Long Beach Peninsula area at an open house in Seaview last Thursday.

Results from the previous Long Beach, Ocean Park and Ilwaco-Seaview meetings held in February and June were presented and more information was gathered from about 70 people at the open house. Data from walking surveys was also presented after three dozen volunteers walked 15 minutes and then reported their age and distance traveled. All this data will be used for the final project that Jeana Wiser is hoping will be ready for publication by the end of 2010.

The resulting report will illustrate where potential vertical evacuation sites can be located in the Long Beach Peninsula area. The vertical evacuation safe havens are designed to be 35 feet above sea level and used by people for up to 24 hours or until the waters recede following a tsunami.

Much of the Peninsula between Ocean Park and Ilwaco is less than 20 feet above sea level. The risk is further exacerbated by scientists' belief that the ground level of the entire coast will plunge about six feet during the course of the next cataclysm subduction-zone earthquake, something that happens roughly every 500 years on average.

There are currently 13 earthen berms suggested in the preliminary report from Vandalia to Surfside. They could accommodate over 6,200 people. Berms with multi-purpose uses in the community are the largest areas suggested to be safe havens. Towers are less expensive, but not able to hold nearly as many people.

Next steps

Ron Kasprisin is a "blue collar" architect who designs functional spaces in cities and landscapes that "perform powerful focused tasks." In January he will have a three-day charette on the Peninsula to seek input on exactly what kind of vertical evacuation structures will be proposed for our area. Kasprisin, who is also a watercolor artist, says a charette is a conference that comes away with a product. In this case the product will be specific plans for vertical evacuation structures, including uses for the community good when they are not needed as safe havens, and it will augment the UW Hazards Mitigation Institute studies.

The studies are designed to help prepare the coastal community for a "worst-case scenario" like the 9.1 magnitude Cascadia earthquake of Jan. 26, 1700. That earthquake triggered a series of tsunami waves 22 feet high that hit the Peninsula at almost 600 miles per hour. The earthquake also caused the Peninsula to drop six feet in elevation so it was beneath a total of 28 feet of water.

Determining exact locations of vertical evacuation berms or towers and how they will be funded and maintained may be years from becoming a reality.

"The UW Hazards Mitigation Institute report on tsunami safe havens is a beginning, a first step in becoming prepared," Wiser says.

If history holds true the next "big one" from the Juan de Fuca Plate fault zone could happen as early as the end of this century.

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