Application of Method of Spectral Component Ratio of Wavelet-Packets to Discrimination between Earthquakes and Nuclear Explosions

The spectral analysis method is widely used in discrimination between nuclear explosions and earthquakes. As a stationary method, it has low resolution due to its invariable time‐frequency window, even if the Gabor transform is adopted. To improve its resolution, a wavelet transform is applied to the analysis of earthquakes and nuclear explosions, which were recorded at the Ürümqi seismic station in the Xinjiang Autonomous region. And a criterion of spectral component ratio of wavelet‐packets (SCRWP), which is used to identify the earthquakes and nuclear explosions, is proposed. Analysis of data of the India nuclear test recorded by the Yellow Knife Seismic Array in Canada has also confirmed that the SCRWP method is rather effective in discrimination between nuclear explosions and earthquakes. The result shows that the SCRWP value is generally higher than 1.0 for earthquakes, but usually less than 1.0 for nuclear explosions.