A probabilistic tsunami hazard analysis of California

We have computed maps of probabilistic tsunami inundation hazard for California using a hybrid approach of numerical tsunami simulations and probabilistic integration of the hazard. The earthquake sources mainly include large subduction zone sources around the Pacific Rim. Our method uses a two-step process: the first step consists of the computation of probabilistic offshore waveheights, based on several thousands of scenario calculations, that include both epistemic uncertainty through the use of logic trees as well as aleatory variability, by applying a standard deviation (sigma) to the probabilistic waveheights. We then use these offshore waveheights, and the source disaggregation, to develop sets of fully non-linear tsunami simulations, including inundation, that span the range of probabilistic offshore waveheights. We present inundation maps for several return periods of engineering interest and discuss their implications and use for infrastructure applications.