Abstract: Using digital waveform data of 52 regional fixed broad band stations in the Sichuan Digital Seismic Network and two profiles of 52 temporary broad band seismic stations, we applied the receiver function inversion and the common conversion point (CCP) stacking method to study crustal structure in Sichuan area. The result shows that there is obvious difference in the depth of Moho between Tibetan Plateau in west Sichuan and the Sichuan basin, the crust in the western plateau of Sichuan is about 52~68 km thick, and the crust in Sichuan—Yunnan block is about 50~60 km thick, the discontinuous low velocity layer is found at the middle crust. The crust thickness of the Sichuan basin is about 38~45 km, and there is no low velocity layer in the crust. The Moho depth is from more 60 km in the west Sichuan to about 40 km in the Sichuan basin. In the boundary zone located in the Longmenshan fault, there is a decline belt of the depth about 30 km, which shows that the Moho discontinuity is complex due to be affected by the Longmenshan fault, and the interface of the upper crust in the plateau is deeper than that in the basin. The upper middle crust has a discontinuous lowvelocity layer in the plateau. There is a brittle nappe moving south east in the bottom of Songpan—Ganzi upper crust, and brittle materials flow to the south and south east in the bottom of Qiangtang—Litang upper crust.

Key words: Receiver function method, Crustal structure, Sichuan Area