Seismic Shear Waves as a Discriminant between Earthquakes and Underground Nuclear Explosions
TELEDYNE GEOTECH ALEXANDRIA VA SEISMIC DATA LAB
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The theoretical amplitude ratio of shear waves to compressional waves is computed using point double-couple representations of earthquakes. These ratios are compared to earthquake data from the LRSM and VELA observatory network. The earthquake data on shear-to-compressional ratios from this network is directly compared to that from NTS underground nuclear explosions. The shear-to-compressional ratio in the teleseismic distance range is found to be significantly greater for earthquakes than explosions, especially in the short- period band. However, use of shear wave data to discriminate between earthquakes and explosions is hampered by a high detection threshold.
- Seismic Detection and Detectors