Testing Crustal Fault Tsunami Sources in the Salish Sea: Comparing Modeled Inundation With the Geologic Record at Discovery Bay, WA
Description:
Crustal faults across the Salish Sea are capable of producing M7+ earthquakes and hazardous tsunamis in Puget Sound and the Strait of Georgia. A better understanding of the history of Salish Sea tsunamis and their sources will improve tsunami hazard assessments in Washington State and British Columbia. The Seattle and Tacoma faults are well-studied tsunami sources, but other Salish Sea crustal faults are just starting to be evaluated for their tsunami hazard. One way to advance our understanding of crustal fault tsunami hazards is to compare modeled tsunami inundation from various sources with geologic evidence for past tsunamis. The tidal marsh at Discovery Bay, Washington, is an excellent geologic recorder of past tsunamis because of its wave-amplifying funnel-shaped morphology, an abundant sediment supply, and a terminal tidal marsh that has preserved tsunami deposits in the marsh stratigraphy. With at least 10 tsunami deposits of thicknesses between 2-10 cm thick, and at least 6 thinner layers under 1 cm thick spanning the last ~3,000 years, the deposits at Discovery Bay likely represent not only tsunamis generated by the Cascadia subduction zone, but also those generated by crustal faults, landslides, or tsunamis from other Pacific subduction zones. To better understand potential crustal fault sources of Discovery Bay tsunami deposits, we test high-resolution tsunami inundation models of the Skipjack Island, Darrington-Devils Mountain, South Whidbey Island, Seattle, and Tacoma fault zones. We also test tsunami inundation models of the 1700 C.E. Cascadia subduction zone and 1964 Great Alaskan earthquake tsunamis, both of which have probable deposits at Discovery Bay. Some of the crustal fault sources we tested appear to be more likely to cause flooding at Discovery Bay than others and may be the sources for deposits whose ages do not align with known Cascadia earthquakes.
Session: Six Decades of Tsunami Science: From the Source of the 1964 Tsunami to Modern Community Preparedness [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Christopher
Student Presenter: No
Invited Presentation:
Authors
Yong Wei Corresponding Author yong.wei@noaa.gov University of Washington |
Carrie Garrison-Laney cegl@uw.edu University of Washington |
Christopher Moore Presenting Author christopher.moore@noaa.gov National Oceanic and Atmospheric Administration |
Clint Pells clint.pells@noaa.gov University of Washington |
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Testing Crustal Fault Tsunami Sources in the Salish Sea: Comparing Modeled Inundation With the Geologic Record at Discovery Bay, WA
Category
Six Decades of Tsunami Science: From the Source of the 1964 Tsunami to Modern Community Preparedness