Seismic Calibration of Group 1 IMS Stations in Eastern Asia for Improved IDC Event Location

摘要

The determination of accurate seismic locations for detected events is one of the most important functions of nuclear test monitoring because location plays such a key role in nuclear test monitoring. In order to establish a robust nuclear test monitoring capability, it is necessary to calibrate the IMS seismic stations used in monitoring, to account for systematic deviations from the nominal travel time curves. This report presents a summary of the research which has been accomplished during the three year program directed at the seismic calibration of the 30 Group 1 IMS stations of Eastern Asia. A Consortium of institutions, led by SAIC (formerly Maxwell Technologies, Inc.) was assembled to address this calibration effort. This consortium included the Massachusetts Institute of Technology's Earth Resources Laboratory, Weston Geophysical Corporation and the Russian Institute for Dynamics of the Geospheres. The consortium approach used a three dimensional velocity model to estimate SSSC at each station, supplemented with empirical corrections to take rigorous account of all the calibration data available for source regions surrounding each station. P-wave and S-wave SSSCs now have been determined and delivered to DTRA for all 30 Group 1 stations for surface focus and ten additional source depths.