Kirchoff Coda Migration of Regional Network Data

9417493 Revenaugh This research is to study the early portion of seismic high frequency records dominated by complicated ground motions comprising the coda of the direct body wave phases. Energy within the coda derives from many sources, including: source region heterogeneity, mantle multipathing, and local site response, the latter being an important contributor to strong ground motion and, hence, to seismic hazard. Recent work has drawn attention to the role of scattering from topography and fault zone heterogeneity - often 10's of kilometers away - in producing energetic coda arrivals for large, local earthquakes. Data from a number of seismograph networks will be analyzed using a variant of Kirchoff migration. Once specific sites of high scattering potential have been identified, their contribution to seismic hazard can be further examined with short-term deployments of portable seismographs. This research is a component of the National Earthquake Hazard Reduction Program. ***