9418248 Davis This research is to study the core-mantle boundary by means of seismic array analysis. The new methods to be used include the directional determination ability of arrays and signal processing techniques developed in the RADAR community. Data from several seismic arrays throughout the world will be used to explore the topography and reflective properties of the core-mantle boundary, which is a key feature in the development of competing mantle convection models. The results of this study will be compared with earlier tomographic work based upon travel-time analysis alone. *** ??