Inversion of single-station teleseismic P-wave polarization data for the velocity structure sf Beijing area

Broadband three-component seismic data recorded by Beijing station (BJI) of CDSN were used to calculate P-wave polarization of teleseismic events. The se polarization data were then used in the inversion for the underground st ructure around the Beijing station, especially for the details of velocity discontinuities. The result shows that a conspicuous low velocity zone exis ts in the crust on the west of the station, which is in good agreement with previous studies. It proves the theory that polarization data could be app lied to inversion for velocity structures, especially for boundaries with l arge velocity gradient. It also demonstrates the feasibility of velocity st ructure inversion with polarization data from high-quality broadband data r ecorded by a single station. Therefore, travel-times and polarization data can be jointly used to study velocity structure. Polarization data are more suitable for delineating the boundary of velocity anomalies. Moreover, if the polarization method is combined with receiver function method to fully exploit their complementarity. it is possible to obtain the lateral velocit y variation around the station as well as the detailed vertical variation b elow the station.