On Bainbridge Island, we’re recently become aware of our community’s risk for tsunami danger. In July, the Washington State Geological Survey issued the results of a series of simulations that show that a 7.5 earthquake on the Seattle Fault will likely generate tsunamis as high as 32 feet on the Bainbridge coastline within 2 to 3 minutes.
The potential for large, devastating tsunamis is even greater along the state’s western coastline, which parallels the Cascadia Subbduction Zone. Many of the coastal towns don’t have easy access to elevated ground. For this reason, coastal communities have for years been discussing the possibility of constructing elevated platforms strong enough to withstand earthquakes and ensuing tsunamis. The Shoalwater Bay Tribe just completed in August its construction of the first ever such free-standing platform in the United States.
The platform, located near the town of Tokeland, is built to accommodate 400 people and is intended to serve the evacuation needs of the entire Shoalwater Tribe and of residents of Tokeland.
Additional platforms are planned for Ocean Shores and Westport. An elevated structure that is part of an elementary school in Westport was completed in 2016. The Institute for Hazards Mitigation Planning and Research at the University of Washington analyzed coastal evacuation needs in 2021, concluding that 50 such structures should be built along the coastline.
If you feel an earthquake when at sea level, get to higher ground immediately.
Featured image of Tokeland platform by Tom Banse for The Washington Military Department.