S Wave Velocity Structure Of The Crust Of The North China Basin And Its Adjacent Area Obtained With Linear Inversion Of The Receiver Function

North China basin is an important tectonic unit in the east of China, which has a large amount of oil and gas resources, as well as the political and cultural center of China. Therefore, North China Basin and the edge has been much attention of Geology and earth physicist. The obtainment of the S-wave velocity structure of the crust in the region is important for the study of crustal deformation, the deep reform, earthquake focal mechanism and seismogenesis.We collected the teleseismic earthquakes recorded of 72 permanent seismic stations in North China. We obtain and analyze the S wave velocity structure beneath the stations by receiver function inversion. In the processing of the receiver functions, we proposed the method of phase filtering based on S transform.Through the research of this paper, the results show that:(1) The soft threshold filter based on S transform suppresses the frequency mixing interference and highlights the weak reflection signal, which benefit the track of signal wave group and the recognition of thin-layer. The method increases stratigraphic resolution of Moho discontinuity especially, which provides the basis for the rest processing and interpretation of deep seismic reflection profiling.(2) With full consideration to the difference of instantaneous phases between effective signals and noise signals, the phase filtering in time-frequency domain can realize apparent performance. It can effectively suppress mixing frequency interference noise, and improve SNR. Even in the situation with fewer data, the effective weak energy signals can still be detected. However, too big energy difference between effective signals and noise may lead to limited filtering effect.(3) the depth of Moho in the capital circle area is about 33km, the depth is shallow, which may be related to the reduction of the lithosphere thinning caused by the delamination of the lower crust. Beneath the stations within the depth range of depth 4-10km generally exists high velocity layer 2-5km thick, immediately beneath high velocity layer and appear the 2-6km thick relatively low velocity layer, which may reaction complex coupled relation between North China rift basin、Taihang uplift and Yanshan uplift.(4) beneath the transition zone of Taihang Mountain uplift to the North China Basin, the crust structure is more complex, the depth variation range of the Moho surface is large, and the trend is obvious from the west to the East. There is low velocity layer in the crust of Taihang Mountain uplift. There is no obvious high and low velocity layer in the crust near the North China Basin,.(5) the Mohodepth of Luxi uplift area is 31km-34km, relatively shallow. The mantle material upwelling, which caused the partial melting of the crust, so that there was a significant low velocity anomaly in the part of the region.