HR: 09:30h
AN: S51C-07    [Abstracts]
TI: Probabilistic Tsunami Hazard Assessment for California from Distant Sources
AU: Borrero, J C
EM: jborrero@usc.edu
AF: University of Southern California Tsunami Research Center, Viterbi School of Engineering, Los Angeles, CA 90089, United States
AU: * Uslu, B
EM: uslu@usc,edu
AF: University of Southern California Tsunami Research Center, Viterbi School of Engineering, Los Angeles, CA 90089, United States
AU: Okal, E A
EM: emile@earth.northwestern.edu
AF: Northwestern University, Department of Earth and Planetary Sciences, Evanston, IL 60208,
AU: Synolakis, C E
EM: costas@usc.edu
AF: University of Southern California Tsunami Research Center, Viterbi School of Engineering, Los Angeles, CA 90089, United States
AB: California has a substantial tsunami hazard from distant sources. Tsunamis are infrequent, and while there have been substantial advances in emergency preparedness, few -if any- communities have a quantitative understanding of the risk in terms of return periods or probabilities of exceedance. Other than the early work of Houston and Garcia for flood insurance studies and the pioneering 2006 FEMA report of Geist et al for Seaside Oregon, there have been few quantitative studies on probabilistic hazard assessment. To quantitatively evaluate the farfield tsunami threat, time dependent and time independent methods are used to compute probabilities of exceedance for wave heights offshore. Following NOAA's practice we use Green's function style sources which are then superposed to construct composite fault motions and then calculate the resultant evolution to the region of interest. We will provide results with probabilities of exceedance of specific heights, for ports and harbors in California. Northern California has the highest risk with shorter periods with offshore wave heights >1m every 4-10 years and >4m every 100-500 years - the range of return periods reflects different calculation methods. For reference, the wave height offshore Crescent City during the 15 November 2007 Kuril islands tsunami was ~1m. In Southern California, >1m offshore waves are expected every 22-50 years, and >1.5m waves every 100 to 150 years. Depending on the local coastal topography, these values may imply substantial inundation.
UR: http://www.usc.edu/dept/tsunamis
DE: 0560 Numerical solutions (4255)
DE: 3238 Prediction (3245, 4263)
DE: 3275 Uncertainty quantification (1873)
DE: 4564 Tsunamis and storm surges
SC: Seismology [S]
MN: 2007 Fall Meeting