Constraining Moho characteristics with frequency-dependence of receiver function and its application

Based on the full-waveform theoretical seismograms of different Moho velocity models, the receiver functions of different frequencies are calculated, and the performances of different Moho morphologies on receiver functions at different frequencies are analyzed and compared. The numerical results show that when the Moho is complex, the P-S converted wave and the multiple wave will have multi-peak characteristics on the high-frequency receiver functions. Receiver functions of different frequencies based on different Moho velocity models are classified and summarized, and the Moho properties revealed by the actual observation data can be discriminated. Taking the seismic station Gaotai （GTA） in the northeastern margin of Tibe-tan Plateau as an example, this paper analyzed the effects of the receiver functions of different frequencies on the Moho morphology beneath the station. The results show that Moho beneath the station is a velocity transitional zone in which velocity varies in a dominant regular, except for the velocity varies at the azimuth along the Longshoushan fault. Furthermore, we built the Moho velocity model beneath the station by fitting the observation structure. Combining the results of geology and petrology, the causes of this Moho morphology were discussed. It is inferred that various tectonic factors and the upwelling and bottom invasion of the upper mantle thermal materials give rise to the differentiation and exchange of crust-mantle materials in this area, and then the Moho morphology mentioned above is resulted in.