9305172 Zeng This research continues successful theoretical developments supported under previous NSF funding on multiple seismic energy scattering. Here, the researcher will extend the numerical simulation of the multiply scattered wave in a non-uniform absorption and scattering medium, explore various factors affecting the observed seismic coda decay, study the effect of anisotropic scattering processes on the seismic scattering wave decay, incorporate a depth-dependent velocity structure, compare seismic scattering effects between realistic heterogeneous models, and apply the theoretical results to real data. The work will have important application to the estimation of the coda magnitude and site amplification, to the Q variation as a possible precursor to earthquake prediction, to the study of crustal heterogeneity and rheology structure and to the extension of the coda study to the early strong part of the earthquake shaking which progressively damages buildings. This research is a component of the National Earthquake Hazard Reduction Program. ***
