Modeling the Combined Effects of Deterministic and Statistical Structure for Optimization of Regional Monitoring

The differences between earthquakes and explosions are largest in the highest recordable frequency band. In this band, scattering of elastic energy by small-scale heterogeneity (less than a wavelength) can equilibrate energy on components of motion and stabilize the behavior of the Lg wave trapped in the Earth's crust. Larger-scale deterministic structure (greater than a wavelength) can still assume major control over the efficiency or blockage of the Lg and other regional/local seismic waves. This project proposes to model the combined effects of the large- scale (deterministic) and the small scale (statistical) structure to invert for improved structural models and to evaluate the performance of yield estimators and discriminants at selected IMS monitoring stations in Eurasia. This will be accomplished by synthesizing seismograms using a radiative transport technique to predict the high frequency coda (>5 Hz) of regional seismic phases at stations having known large-scale three-dimensional structure, combined with experiments to estimate the effects of multiple-scattering from unknown small-scale structure.