9628682 Olsen This research involves the calculation of three-dimensional strong motion from large earthquakes applied to southern California situations. Intensive computational requirements earlier in this work have led to the development of algorithms that run on massively parallel computers. A 3-D 4th order staggered-grid finite-difference method was used to simulate wave propagation in a model of the Los Angeles basin including the 3-D structures of the Los Angeles and San Fernando basins. The results showed that even moderate earthquakes outside the basins can cause damaging motions within the basin due to basin effects. This project will further earlier work by comparing the 1992 M=7.3 Landers earthquake simulations with actual data, calculating the effect of varying rupture complexity of the earthquakes, and calculating the effects of topographic scattering. This research is a component of the National Earthquake Hazard Reduction Program. ***
