Numerical simulation of seismic wave propagation produced by earthquake by using a particle method
Article first published online: 9 OCT 2012
© 2012 The Authors Geophysical Journal International © 2012 RAS
Geophysical Journal International
Volume 191, Issue 3, pages 1305–1316, December 2012
How to Cite
Takekawa, J., Madariaga, R., Mikada, H. and Goto, T.-n. (2012), Numerical simulation of seismic wave propagation produced by earthquake by using a particle method. Geophysical Journal International, 191: 1305–1316. doi: 10.1111/j.1365-246X.2012.05676.x
- Issue published online: 12 NOV 2012
- Article first published online: 9 OCT 2012
- Accepted 2012 September 11. Received 2012 August 31; in original form 2011 November 10
- Numerical solutions;
- Numerical approximations and analysis;
- Earthquake ground motions;
- Computational seismology
We propose a forward wavefield simulation based on a particle continuum model to simulate seismic waves travelling through a complex subsurface structure with arbitrary topography. The inclusion of arbitrary topography in the numerical simulation is a key issue not only for scientific interests but also for disaster prediction and mitigation purposes. In this study, a Hamiltonian particle method (HPM) is employed. It is easy to introduce traction-free boundary conditions in HPM and to refine the particle density in space. Any model with complex geometry and velocity structure can be simulated by HPM because the connectivity between particles is easily calculated based on their relative positions and the free surfaces are automatically introduced. In addition, the spatial resolution of the simulation could be refined in a simple manner even in a relatively complex velocity structure with arbitrary surface topography. For these reasons, the present method possesses great potential for the simulation of strong ground motions.
In this paper, we first investigate the dispersion property of HPM through a plane wave analysis. Next, we simulate surface wave propagation in an elastic half space, and compare the numerical results with analytical solutions. HPM is more dispersive than FDM, however, our local refinement technique shows accuracy improvements in a simple and effective manner. Next, we introduce an earthquake double-couple source in HPM and compare a simulated seismic waveform obtained with HPM with that computed with FDM to demonstrate the performance of the method. Furthermore, we simulate the surface wave propagation in a model with a surface of arbitrary topographical shape and compare with results computed with FEM. In each simulation, HPM shows good agreement with the reference solutions. Finally, we discuss the calculation costs of HPM including its accuracy.