Near-fault earthquake ground motion prediction by a high-performance spectral element numerical code

Abstract

Near‐fault effects have been widely recognised to produce specific features of earthquake ground motion, that cannot be reliably predicted by 1D seismic wave propagation modelling, used as a standard in engineering applications. These features may have a relevant impact on the structural response, especially in the nonlinear range, that is hard to predict and to be put in a design format, due to the scarcity of significant earthquake records and of reliable numerical simulations. In this contribution a pilot study is presented for the evaluation of seismic ground‐motions in the near‐fault region, based on a high‐performance numerical code for 3D seismic wave propagation analyses, including the seismic fault, the wave propagation path and the near‐surface geological or topographical irregularity. For this purpose, the software package GeoELSE is adopted, based on the spectral element method. The set‐up of the numerical benchmark of 3D ground motion simulation in the valley of Grenoble (French Alps) is chosen to study the effect of the complex interaction between basin geometry and radiation mechanism on the variability of earthquake ground motion.