Seismic Discrimination of Nuclear Explosions at the Lobnor Test Site

The structure of short-period seismic fields was studied from data on underground nuclear explo- sions at the Lobnor test site and earthquakes in western China recorded by four seismic stations in Kazakhstan. As many as 78 records of events with magnitudes m b = 3.4-6.5 obtained between 1969 and 1999 at epicentral distances of 540-2300 km were considered. Amplitude ratios of various phases of P and S waves processed by four narrow-band filters within a frequency range of 0.5-6.0 Hz were analyzed. Optimal parameters and fre- quency bands providing the most efficient discrimination between explosions and earthquakes are determined for each station.