On the modelling of tsunami generation and tsunami inundation

TL;DR

This paper reviews tsunami generation mechanisms, introduces a simple seabed displacement model during earthquakes, and discusses tsunami inundation features including resonance effects and vortex formation.

Contribution

It presents a computationally inexpensive seabed displacement model based on finite fault solutions and explores tsunami features like wave resonance and vortex formation.

Findings

The seabed displacement model effectively simulates earthquake-induced tsunamis.

Resonance effects can amplify tsunami waves, making subsequent waves more destructive.

Macro-scale vortices in tsunamis can be modeled with nonlinear shallow water equations.

Abstract

While the propagation of tsunamis is well understood and well simulated by numerical models, there are still a number of unanswered questions related to the generation of tsunamis or the subsequent inundation. We review some of the basic generation mechanisms as well as their simulation. In particular, we present a simple and computationally inexpensive model that describes the seabed displacement during an underwater earthquake. This model is based on the finite fault solution for the slip distribution under some assumptions on the kinematics of the rupturing process. We also consider an unusual source for tsunami generation: the sinking of a cruise ship. Then we review some aspects of tsunami run-up. In particular, we explain why the first wave of a tsunami is sometimes less devastating than the subsequent waves. A resonance effect can boost the waves that come later. We also look at a particular feature of the 11 March 2011 tsunami in Japan - the formation of macro-scale vortices - and show that these macro-scale vortices can be captured by the nonlinear shallow water equations.