HR: 0800h
AN: S11A-0271    [Abstracts]
TI: Multiresolution Structured and Unstructured Finite Element Method for Three-Dimensional Attenuated Earthquake Ground Motion Modeling in Basins including Topography
AU: * Ichimura, T
EM: ichimura@cv.titech.ac.jp
AF: Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro, Tokyo, 1528552, Japan
AU: Hori, M
EM: hori@eri.u-tokyo.ac.jp
AF: University of Tokyo, 1-1-1, Yayoi, Bunkyo, Tokyo, 1130032, Japan
AU: Bielak, J
EM: jbielak@andrew.cmu.edu
AF: Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 152133890, United States
AU: Shinotake, E
EM: shinotake.e.aa@m.titech.ac.jp
AF: Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro, Tokyo, 1528552, Japan
AB: We present an efficient finite element method (FEM) for large-scale attenuated earthquake ground motion simulation, which reduces modeling and computational costs by using a hybrid structured/unstructured mesh capable of treating underground and above surface topography. The meshing process starts with a uniform high- resolution background cell discretization, after which, using an octree structure, the grid is thinned to tailor the local mesh size to a prescribed fraction of the local shear wavelength. A small number of unstructured finite elements are then introduced to model the irregular free-surface topography. We have also implemented an arbitrary intrinsic attenuation model through Standard Linear Solid (SLSs) models, and verified its accuracy, with a constant Q, for a wave propagation problem in a layered system against the corresponding Greenfs function solution. Finally, we demonstrate the usefulness of the new procedure with a simulation of earthquake ground motion in a realistic 3D model of the Los Angeles basin.
DE: 7200 SEISMOLOGY
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7290 Computational seismology
SC: Seismology [S]
MN: 2007 Fall Meeting