San Fernando Valley Simulation
The top left figure
(based on a model developed by Magistrale,
McLaughlin, and Day at SDSU)
depicts the variations in shear wave
velocity near the free surface in the San Fernando Basin. The
bottom left figure
shows an unstructured mesh constructed so that it employs smaller elements
in softer soils, where seismic wavelengths are small.
The mesh is partitioned for 64 processors. The
figure on the right
displays the maximum surface ground motion (divided by the
free field motion on rock) experienced during a simulated seismic event.
The simulation results indicate that the magnitude of the shaking in
the basin is up to nine times larger than that of the rock, suggesting
substantially greater damage in these regions.
The ground motion was computed on the Cray T3D at the
Pittsburgh Supercomputing Center
using a mesh of 14 million tetrahedra and 2.5 million nodes.