Three-Dimensional Simulation of Long-Period (>1.5 sec) Earthquake Ground Motion in the Valley of Mexico: basin effects

Leonardo Ramirez-Guzman, Marilyn Contreras, Jacobo Bielak, & J. Aguirre

Accepted 2007, SCEC Contribution #1068

Three-dimensional simulations of earthquake ground motion in sedimentary valleys have given a deeper understanding of wave propagation and site effects in urban regions. In this paper we present a preliminary study of the ground motion and resulting amplification in the Mexico City Basin due to strong earthquakes in the Pacific Coast of Mexico. Three variables control our model: material properties, underground topography, and seismic source. Based on the available literature, we propose an initial coarse approximation of Mexico City’s basin, using as background a regional model similar to the one proposed by Furumura and Singh (2002). The seismic excitation is the 14 September 1995 Copala earthquake (Mw=7.3). Our 3D simulation, with a maximum resolution of 0.66 Hz, reproduces qualitatively the amplifications and long durations observed during the actual earthquake. The computation is performed using HERCULES, an octree-based finite element method code (Tu et al, 2006).

Citation
Ramirez-Guzman, L., Contreras, M., Bielak, J., & Aguirre, J. (2007). Three-Dimensional Simulation of Long-Period (>1.5 sec) Earthquake Ground Motion in the Valley of Mexico: basin effects. Presentation at 4th International Conference on Earthquake Geotechnical Engineering.