HR: 1340h
AN: OS23D-1353    [Abstracts]
TI: GIS based Relative Tsunami Hazard Maps for Northern California, Humboldt and Del Norte Counties
AU: * Patton, J R
EM: jpatton@pacificwatershed.com
AF: Pacific Watershed Associates, PO Box 4433, Arcata, CA 95518 United States
AU: Dengler, L A
EM: lad1@axe.humboldt.edu
AF: Humboldt State University Geology Dept., 1 Harpst St, Arcata, CA 95521 United States
AB: Tsunami hazard maps are generated using a geographical information systems (GIS) approach to depict the relative tsunami hazard of coastal Humboldt and Del Norte Counties in northern California. Maps are composed for the Humboldt Bay, Eel River, and Crescent City regions and available online at http://www.humboldt.edu/~geodept/earthquakes/rctwg/toc.html . In contrast to previous mapping efforts that utilize a single line to represent inundation, hazard is displayed gradationally. A 2.5D surface is constructed to represent this hazard. Elevation, normally used for 2.5D surfaces, is substituted with hazard units. Criteria boundaries are used to separate regions of increasing hazard. Criteria boundaries are defined based on numerical modeling, paleoseismic studies, historical flooding, FEMA Q3 flood maps, and impacts of recent tsunamis elsewhere. Zones are constructed to further adjust the criteria with respect to a physically determined variable hazard (e.g. proximity to open ocean). A triangular irregular network (TIN) is constructed using hazard criteria boundaries as breaklines. Fabricated points are necessary to construct a hazard surface and are placed where criteria boundaries diverge or where hazard is nonlinear between criteria boundaries. Hazard is displayed as a continuous gradational color scale ranging from red (high hazard) through orange (medium), yellow (low) to gray (no hazard). The maps are GIS based to facilitate ready adaptation by planners and emergency managers. The maps are intended for educational purposes, to improve awareness of tsunami hazards and to encourage emergency planning efforts of local and regional organizations by illustrating the range of possible tsunami events.
UR: http://www.humboldt.edu/~geodept/earthquakes/rctwg/toc.html
DE: 7223 Seismic hazard assessment and prediction
DE: 4564 Tsunamis and storm surges
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting