Tsunami generation by dynamic displacement of sea bed due to dip-slip faulting

TL;DR

This paper investigates the impact of dynamic sea bed displacement caused by dip-slip faulting on tsunami generation, highlighting differences from static models and explaining complex wave train shapes.

Contribution

It introduces a coupled viscoelastic and shallow water model to account for dynamic fault effects in tsunami simulations, which are often neglected.

Findings

Dynamic effects influence tsunami wave shapes

Differences observed between static and dynamic models

Dynamic modeling explains complex wave train structures

Abstract

In classical tsunami-generation techniques, one neglects the dynamic sea bed displacement resulting from fracturing of a seismic fault. The present study takes into account these dynamic effects. Earth's crust is assumed to be a Kelvin-Voigt material. The seismic source is assumed to be a dislocation in a viscoelastic medium. The fluid motion is described by the classical nonlinear shallow water equations (NSWE) with time-dependent bathymetry. The viscoelastodynamic equations are solved by a finite-element method and the NSWE by a finite-volume scheme. A comparison between static and dynamic tsunami-generation approaches is performed. The results of the numerical computations show differences between the two approaches and the dynamic effects could explain the complicated shapes of tsunami wave trains.