Tele‐Seismic PS‐Wave Splitting from the Basement in the Capital Area of China

Abstract An important advantage of tele‐seismic PS‐waves is carrying the anisotropy information of media beneath seismic stations. This paper uses the analysis method of three‐component PS‐wave splitting to analyze the basement PS‐waves based on the high‐precision tele‐seismic data of Capital Area Seismic Network (CASN) from 2002 to 2003. The purpose is to acquire the PS‐wave splitting parameters beneath the seismic stations, including polarization of fast PS‐waves and the time delays of fast and slow PS‐waves, and to reveal the shallow crust anisotropy beneath the seismic stations. The results show that this method preserves the original information of the wave field, which allows us to analyze the features of PS‐wave splitting. The tele‐seismic PS‐waves from the basement recorded by short period stations have the advantage of less noise and higher SNR, and have splitting phenomena commonly. Besides we find the time delay of fast and slow PS‐waves is beyond our expectation, which has average values of time delay 0.1∼0.2 s. This research can be compared with shear‐wave splitting, which would help recognize anisotropy and stress state of crust and study tectonics and seismic activity.