9506767 BOYD This research is to digitally scan seismic phase observations tabulated in the International Seismological Summary (ISS) and Bureau Central International Seismologique (BCIS) catalogs, use these observations to compute high quality hypocenters based on techniques developed within the last few years, make tectonic interpretations based on these relocated earthquakes, and make the digitized phase observations and the recomputed hypocenters available to interested research groups. The result will be a much more complete and accurate seismicity catalog, especially prior to 1964 when the WWSSN program was implemented, that can be used to understand deformation and seismic hazard within the U.S. and throughout the world. This research is a component of the National Earthquake Hazard Reduction Program. ***