Large-scale Simulation of Elastic Wave Propagation in
                  Heterogeneous Media on Parallel Computers

       Hesheng Bao, Jacobo Bielak, Omar Ghattas, Loukas F. Kallivokas,
          David R. O'Hallaron, Jonathan R. Shewchuk, and Jifeng Xu
 Department of Civil and Environmental Engineering / School of Computer Science
                         Carnegie Mellon University
                       Pittsburgh, Pennsylvania 15213

This paper reports on the development of a parallel numerical methodology for
simulating large-scale earthquake-induced ground motion in highly heterogeneous
basins. We target large sedimentary basins with contrasts in wavelengths of
over an order of magnitude. Regular grid methods prove intractable for such
problems. We overcome the problem of multiple physical scales by using
unstructured finite elements on locally-resolved Delaunay triangulations
derived from octree-based grids. The extremely large mesh sizes require special
mesh generation techniques. Despite the method's multiresolution capability,
large problem sizes necessitate the use of distributed memory parallel
supercomputers to solve the elastic wave propagation problem. We have developed
a system that helps automate the task of writing efficient portable
unstructured mesh solvers for distributed memory parallel supercomputers. The
numerical methodology and software system have been used to simulate the
seismic response of the San Fernando Valley in Southern California to an
aftershock of the 1994 Northridge Earthquake. We report on parallel performance
on the Cray T3D for several models of the basin ranging in size from 35,000 to
77 million tetrahedra. The results indicate that, despite the highly irregular
structure of the problem, excellent performance and scalability are achieved.


From Computer Methods in Applied Mechanics and Engineering 152(1-2):85-102,
22 January 1998.


BibTeX entry:

@article{bao98,
author = {Hesheng Bao and Jacobo Bielak and Omar Ghattas and Loukas F.
  Kallivokas and David R. O'Hallaron and Jonathan R. Shewchuk and Jifeng Xu},
title = {Large-scale {S}imulation of {E}lastic {W}ave {P}ropagation in
  {H}eterogeneous {M}edia on {P}arallel {C}omputers},
journal = {Computer Methods in Applied Mechanics and Engineering},
volume = 152,
number = {1--2},
pages = {85--102},
month = jan,
year = 1998
}