Tsunami Hazard Assessment of the Strait of Juan de Fuca

This study presents and discusses the tsunami hazard posed by an updated CSZ earthquake scenerio to the coastal communities of Port Angeles and Port Townsend, based on the results of a high resolution GeoClaw simulation with 2/3 arc second resolution (about 20.56 meters) surrounding these towns. In addition, we will also present the results of a coarse regional simulation of the Strait of Juan de Fuca. This coarse study encompasses 28 regions that span the Strait’s coast, including the communities of Anacortes, Bellingham, Friday Harbor, and Victoria, BC in addition to extended areas around Port Angeles and Port Townsend. The finest grid for these 28 regions where we collected results had 2 arc sec resolution (around 62 meters). Finally, we will discuss some inherent uncertainties in the specification of the earthquake scenario, the limitations of the GeoClaw model, and the associated uncertainites in the results.

This report documents the results of a study supported by the Washington State Emergency Management Division of the tsunami hazard along the Strait of Juan de Fuca. Results include inundation depths and times of arrival that will be useful to communities along the Strait as well as speeds, momentum, momentum flux, and minimum water depths that are useful for harbor masters and the major shipping and ferry industries that operate within the Strait of Juan de Fuca.

Washington State Emergency Management Division