Physics-based large-deformation analysis of coseismic landslides: A multiscale 3D SEM-MPM framework with application to the Hongshiyan landslide

A multiscale framework is developed based on the spectral element method (SEM) and material point method (MPM) for the large-deformation analysis of coseismic landslides. At a regional scale, SEM is used to model elastic wave propagation from a seismic source to a local site with complex topography. At a local scale, the coseismic landslide process and large deformation behavior are simulated by a nonlinear MPM model. Therefore, the proposed SEM-MPM model is able to reproduce the entire coseismic landslide process, including triggering, sliding and deposition. In this study, the coupled SEM-MPM method is used to simulate the massive Hongshiyan landslide triggered by the 2014 Ms6.5 Ludian earthquake in China. The study shows that the domain reduction method is able to reproduce the complex wave field across the SEM and MPM platforms, especially the strong topographic amplification of ground motion on the mountain ridge, which triggered the catastropic failure of the Hongshiyan landslide. The simulated volume of the sliding mass, sliding velocity, and final deposition profile are comparable with the field data and previous numerical studies, showing that the SEM-MPM method is a promising physics-based numerical tool for an integrated study of coseismic landslides.