Effect of Tsunami Damage on Passenger and Forestry Transportation in Pacific County, Washington

Abstract

The outer coast of Washington State is exposed to significant seismic and tsunami hazards. A Cascadia subduction zone (CSZ) event is expected to cause high earthquake intensities and tsunami inundation, resulting in considerable infrastructure loss, inundation of developed land, and degraded functioning of coastal communities. One area of particular concern is Pacific County, in southwest Washington, where more than 85% of the population is expected to experience severe shaking intensities. This paper establishes the predisaster passenger and freight transportation patterns and the predicted damaged postdisaster road network in Pacific County. The hazard used in the analysis was a CSZ magnitude 9.1 earthquake with Washington asperity and resulting tsunami. The anticipated change in trip distance and the percentage of trips that could no longer be completed were used to compare passenger travel and forestry freight travel. Because passenger and freight travel have different purposes and patterns, understanding how they are affected differently can serve as a foundation for community-based disaster recovery planning to increase community resilience in earthquakes and tsunamis.