APPLICATION OF NUMERICAL MODELING OF TSUNAMI INUNDATION USING UPSCALED URBAN ROUGHNESS PARAMETERIZATION -CASE OF 2011 TOHOKU EARTHQUAKE TSUNAMI IN ONAGAWA-

Abstract

 Numerical simulation of tsunami using ultra high-resolution topography (resolution is less than 1m) enables to consider the effect of structures on wave run-up. However, numerical simulation with medium resolution (resolution is around 100m) is still used and important for practical use due to computational cost. This study develops Drag Force Model (DFM) as upscaled urban roughness parameterization to obtain acceptable accuracy in medium resolution tsunami model based on physical modeling. Survey results by The 2011 Tohoku Earthquake Tsunami Joint Survey (TTJS) Group are used for its validation with previous models. The model differences give little difference in terms of the maximum inundated depths and inundated area. However, DFM estimates larger resistance forces corresponding to the existence of structures (in particular a group of structures in nearshore area) than other models and the momentum fluxes decrease about twice.