Applicability of a particle method with arbitrary particle refinement for elastic wave propagation

Abstract

A particle based continuum model is presented for seismic wave propagation with an arbitrary refinement of spatial resolution. In the present study, we apply a Hamiltonian Particle Method (HPM) to the simulation of seismic ground motion. HPM has some advantages over the conventional continuum simulators in terms of; (i) the traction-free boundary conditions are automatically introduced, (ii) the data structure in HPM become simple, (iii) an arbitrary refinement of spatial resolution can be carried out easily. First, we simulated the seismic wave propagation in a homogeneous media using several numerical models. The models were partially refined in space, but the refinement level of each model was different. This numerical test was conducted to confirm whether the refinement of spatial resolution in HPM generates the artificial dispersion or not. The obtained results showed that the abrupt refinement of particles can be accepted in HPM. Next, we made the heterogeneous model with the low velocity zone modeled after the sedimentary basin structure to demonstrate the effectiveness of refinement technique in HPM. Our results showed that HPM can reproduce seismic ground motion on the free surface with the arbitrary spatial refinement. This means that the method can be an alternative to existing simulators of seismic ground motion.