Influence of geometrical characteristics of tsunami source on normal modes of alongshore oscillation

Abstract

This study investigates the relationship between the tsunami source geometry and its local amplifications due to resonance. Linear long wave equations were first applied for computations of the 2011 Tohoku earthquake tsunami and the Nankai earthquake tsunami, respectively, and focusing sites were selected where dominant amplification was observed at a certain frequency. The model was also applied for computations of tsunami generated from the unit sources at various locations. Power spectra and phase of the computed surface water fluctuations at the focusing sites were plotted at locations of unit source. Influence of the tsunami source geometry was finally discussed based on the obtained spatial distributions of power spectra and phase.