RMS Lg Studies of Underground Nuclear Explosions in the U.S.S.R. and the U.S.

Abstract : This final report is in six sections. Section one describes a new method for interpreting radiation patterns of surface waves from underground nuclear explosions at the Balapan Test Site, East Kazakhstan. We add information from body waves and RMS Lg, to conclude that strike directions of inferred faulting lie in the range 90 deg to 120 deg. This section has an Appendix. Section two describes a successful method, based on high-frequency P/Lg spectral ratios, of discriminating between small earthquakes and industrial explosions in the eastern U.S. Section three gives location estimates, derived from SPOT photographs, of 83 nuclear explosions at the Balapan Test Site. Section four describes the seismicity at the Nevada Test Site that is apparently induced by nuclear explosions. This study has relevance in the context of on-site inspections that might be associated with monitoring a comprehensive test ban. Section five describes analog data from China, used to obtain Lg magnitudes for two Soviet nuclear explosions, for which Lg data had not previously been available. Section six describes digital data from Borovoye station in Kazakhstan. RMS Lg for 12 Soviet nuclear explosions show scatter of only a 0.024 magnitude units against NORSAR mb(Lg). Regional seismic-waves, Yield estimation, Discrimination of earthquakes and explosions.