Variations in community evacuation potential related to average return periods in probabilistic tsunami hazard analysis

International Journal of Disaster Risk Reduction
By: , and 

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Abstract

Tsunami risk management requires strategies that can address multiple sources with different recurrence intervals, wave-arrival times, and inundation extents. Probabilistic tsunami hazard analysis (PTHA) provides a structured way to integrate multiple sources, including the uncertainties due to the natural variability and limited knowledge of sources. PTHA-based products relate to specific average return periods (ARP) and while there has been considerable attention paid to ARP choice for building codes, guidance on ARP choice to support evacuation planning and related land use is lacking. We use the State of California (USA) coastal communities as a case study to explore the use of geospatial analysis and pedestrian-evacuation modeling for comparing the societal implications of tsunamis based on evacuation areas that reflect inundation from 475-year, 975-year, and 2475-year ARPs. Results demonstrate that changes in PTHA ARP had a substantial effect on the number of tax-lot parcels in PTHA evacuation areas, but not on the primary land use of these parcels or which communities had the largest number of exposed parcels. Composite PTHA maps provided high-level insights on hazard exposure and identified dominant sources; however, disaggregated PTHA outputs that reflect single source parameters (e.g., wave-arrival time) were necessary to quantify evacuation potential from local and distant tsunamis. Framing changes in ARP assumption based on changes in the number, land-use type, and potential evacuation challenges of parcels in evacuation areas can provide valuable insight on the real-world implications of which ARP to use in land use or evacuation planning.

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    Publication type Article
    Publication Subtype Journal Article
    Title Variations in community evacuation potential related to average return periods in probabilistic tsunami hazard analysis
    Series title International Journal of Disaster Risk Reduction
    DOI 10.1016/j.ijdrr.2020.101871
    Volume 50
    Year Published 2020
    Language English
    Publisher Elsevier
    Contributing office(s) Western Geographic Science Center
    Description 101871, 14 p.
    Country United States
    State California
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