A particle method for seismic wave propagation on arbitrary surface of the ground

Abstract

A particle-based continuum model is presented for the simulation of seismic wave propagation. Accurate simulation of seismic ground motion for the model with arbitrary free surface of the ground is a key issue for not only scientific interest but also in practical fields to estimate seismic signals traveled through subsurface structure. In the present study, a Hamiltonian particle method (HPM) is proposed to seismological numerical modeling. HPM has some advantages comparing to traditional continuous and discontinuous methods in terms of; (i) the introduction of the traction-free boundary conditions is easier than that in finite difference methods (FDM), (ii) data structure in HPM is simpler than that in finite element methods (FEM) because of no need to consider the connectivity between nodes and elements when discretizing object of analysis, and (iii) no need to calibrate material parameters that is a cumbersome process in distinct element method (DEM) with a hexagonal arrangement. In this paper, we first calculate the seismic wave propagation in a homogeneous media and compare the results with that from FDM to demonstrate the performance of the method. Next, we simulate surface wave propagation in a model with arbitrary surface topology. These results indicate that HPM can calculate elastic and surface wave propagation with sufficient accuracy for models with a free surface of arbitrary shape.