Relation between the period of leading tsunami wave and source parameters

Abstract

Tsunami waves can be significantly amplified by coastal topography, and it is known that the amplification is greatly associated with the period of tsunami wave. This study focuses on the period of leading tsunami wave and aims to find out its relationship with the source parameters. Statistics on the water level records of historical tsunami events show that the leading wave in most events is risky and its period has significant correlation with some source parameters. To clarify the relationship between the leading wave period and the source parameters, an analysis based on the numerical simulation of idealized tsunami scenarios has been conducted. The results suggest that the leading wave period shows strong anisotropy associated with the feature of seismic source. The period in the major direction is mainly affected by the magnitude and focal depth. In addition, water depth near the source also shows a great influence to the period in the idealized cases, but the influence is concealed by the complex topography in the real situation. Based on the idealized analysis, a formula for estimating the period of tsunami leading wave is proposed and applied to historical events. Reasonable predictions are obtained for tsunamis originated from deep water.