Improving Our Understanding of Tsunami Hazards in the Salish Sea: Comparing Source Models and Geologic Records

Shallow-crustal faults across the Salish Sea of the Pacific Northwest are capable of producing M7+ earthquakes, potentially generating devastating tsunamis near populated coastlines and ports in Puget Sound and the Strait of Georgia. Submarine landslides also have the potential to generate tsunami heights of tens of meters. Geologic records of tsunami deposits at Discovery Bay, WA, and other sites in the Salish Sea, likely represent not only known tsunami sources including the Cascadia subduction zone, but also other tsunami sources, potentially including shallow crustal earthquakes and landslides. Modeling of the Seattle fault tsunami source greatly improved the knowledge of Salish Sea tsunami hazards, but the hazards posed by other nonCascadia sources of Salish Sea tsunamis are not as well studied. To improve the understanding of Salish Sea tsunami hazards, we compare the distribution of tsunami deposits against high-resolution tsunami inundation models of Salish Sea crustal earthquakes and landslides, including the Devils Mountain fault zone, the Skipjack Island fault, the South Whidbey Island fault, the Seattle fault, and the Frasier River Delta landslide. We expect these results will provide improved correlation between source models and geological records and thus a more comprehensive understanding of Salish Sea tsunami hazards, critical for vulnerable coastal communities and major ports.