Séance Séminaire

Séminaire ACSIOM

Numerical modelling of seismic waves by high-order discontinuous methods

In this talk we present and analyse high-order discontinuous Galerkin (DG) methods for the numerical modelling of the ground motion induced by large earthquakes. DG methods allow for local adaptivity on discretization parameters, thus improving the quality of the solution without affecting the computational costs. This approach is particularly well suited for the simulation of complex wave phenomena, such as the seismic response of sedimentary basins or soil-structure interaction problems, where flexibility and accuracy are crucial in order to simulate correctly the wave-front field while keeping affordable the computational effort. The theoretical properties of the semidiscrete formulation are discussed, including stability and error estimates. A discussion on the dissipation, dispersion and stability properties of the fully-discrete formulation obtained through an explicit time marching scheme is also presented. Some validation benchmarks are shown to verify the practical performance of the proposed scheme. We also present simulations of real large-scale seismic events in three-dimensional complex media that include both far-field to near-field as well as soil-structure interaction effects. The numerical results have been obtained with the high performance, open-source code SPEED (https://speed.mox.polimi.it) jointly developed at Politecnico di Milano by The Laboratory for Modeling and Scientific Computing of the Department of Mathematics and the Department of Civil and Environmental Engineering.