Simulation of the hydro-acoustic and gravity waves generated by a landslide

Abstract

In this work we propose a linear model describing the propagation of acoustic waves and gravity waves in the ocean. This model can be used for describing the propagation of a tsunami and the acoustic waves generated by an underwater earthquake or a landslide. The acoustic-gravity waves are considered as first order perturbation of an equilibrium state for the ocean. The equilibrium state is as follow: there is no mean current and the pressure, temperature and density are vertically stratified. The model is obtained from a linearization around this equilibrium state of the compressible Euler equations. Unlike several other works on acoustic-gravity waves, the two types of waves are not decoupled during the linearization. The complete derivation of the model and the comparison with the other models of the literature are presented in [1]. As a first application we present the simulation of a simplified landslide. We aim at a better understanding of the acoustic wavefield generation process. The equations are discretized with the finite element method in space and a finite difference scheme in time. In-field data on the acoustic waves generated by a landslide are already available in the literature [2] and provide the relevant scales for the simulation. [1] Juliette Dubois, J., Imperiale, S., Mangeney, A., Bouchut, F., Sainte-Marie J. (2022), Acoustic and gravity waves in the ocean: a new derivation of a linear model from the compressible Euler equation, Submitted. [2] Caplan-Auerbach, J., Dziak, R. P., Bohnenstiehl, D. R., Chadwick, W. W., and Lau, T.- K. (2014), Hydroacoustic investigation of submarine landslides at West Mata volcano, Lau Basin, Geophys. Res. Lett., 41, 5927– 5934, doi:10.1002/2014GL060964.