THE TAU METHOD INVERSION AND THE CRUST STRUCTURE RESEARCH
HUANG YI-PING TENG JI-WEN(Institute of Geophysics, Academia Sinica)
In order to obtain the structure and the velocity distribution in the crust and upper mantle, the tau method which is widely used in explosion seimology is studied in this paper. Based on Bessonova.'s method (1974), some improvements for minimizing the uncertainty of solution and simplifying the inversion procedure are presented.1. The inversions of the upper and lower boundaries of τ(p) are carried out and after that the previous results are summed up.2. The effect of low velocity layers can be subtracted from the initial model in the tau method.The application of above approaches has led to fairly satisfactory results.Bessonova's method is applied to deep seismic sounding data of the Bast China. The results indicate that the crustal thickness in this region is about 31 km; there exists a low-velocity layer of 6 km thick (Vp=6 km/sec) at the depth of 18 km.