Analysis of Teleseismic P Wave Amplitude and Coda Variations for Underground Explosions

摘要

This report presents the results of four investigations which have as their common goal, the development and application of techniques for determining near-source contributions to the observed variations in short-period P wave amplitudes, travel times, waveforms and coda for underground explosions. A waveform modeling analysis of long-period teleseismic SH and SV waves from two large underground explosions at the Southern Novaya Zemlya test site indicates that the appropriate equivalent double couple orientation for the tectonic release is vertical strike slip. complete waveform modeling of the SV signals using the method of Baag and Langston allows us to distinguish between the strike slip and 45 deg. dipping thrust geometries. The resulting mechanism and associated F-factors indicate that teleseismic P waves from these events are probably not strongly affected by tectonic release radiation, consistent with the previous coda and P wave amplitude analysis we conducted under our previous contract. (rh)