Analysis of factors influencing simulations of the 1993 Hokkaido Nansei-Oki and 1964 Alaska Tsunamis

The purpose of this paper is to examine factors influencing numerical simulations of tsunamis, and their implications for hazard mitigation. We focus on a specific finite element hydrodynamic model, chosen for its role in the systematic development of inundation maps for regions threatened primarily by Cascadia Subduction Zone (CSZ) tsunamis. However, in part for generality and in part because of poor historical records for CSZ events, we discuss here the performance of the model in the context of better documented past events with epicenters located elsewhere: the July 12, 1993 Hokkaido Nansei-Oki and the March 28, 1964 Alaska tsunamis. Our analysis includes the influence of grid refinement, interactions between tides and tsunamis, artificial energy loss, and numerical parameterization. We show that while the ability exists to reproduce past events, limitations remain in the modeling process that should be accounted for in translating modeling results into information for tsunami mitigation and response.