Phase-Matched Filter: Application To The Identification Of Surface Waves

Identification of nuclear test evoking seismic events from multitudinous inartificial seismic events comprises the dominating part of implement of Comprehensive Test Ban Treaty(CTBT). The method of detection ability enhancement of surface wave signals for weak events is studied. Moreover, this method is applied to a set of events at regional stations. The thesis is comprised of three main parts, (1) On the base of the multiple filter analysis method (MFT) put forword by Dziewonski et al, the reliability of the method is verified. Using the MFT, the dispersion curves of Semipalatinsk,Nevada,Lop Nor are obtained as well as the characters of these curves are analyzed. (2) According to the given path dispersion curve, the design and confirmation of Phase-matched filter are realized theoretically. Meanwhile, the detection of surface wave signals for weak events and the validity test of the method are carried out. (3)Through mb : Ms, the discriminating performance of this method is compared with USGS(United States Geological Survey) results, which proves that using this method, discriminating large part of events and lower the threshold value of surface wave detector are feasible.