Abstract:We use the shear-wave splitting (SAM) method to calculate the fast shear-waves polarization direction and slow shear-waves time delay of 8 stations in southern Liaoning, based on near-field small seismic waveform data of seismic network from 2008-01 to 2018-12 in Liaoning Region. We mainly analyze the shear-wave splitting parameters of Yingkou (YKO) station and Gaixian (GAX) station. The results show that: 1) The dominant polarization directions of the fast shear-waves at the 8 stations are mainly NE-NEE and NW. Among them, the fast wave polarization directions of 5 stations are NE and NEE, which are basically consistent with the regional geological structure and the direction of the maximum principal stress field in northern North China. 2) The detailed analysis of the shear-wave splitting results of YKO and GAX stations show that the dominant polarization directions of the shear-waves of YKO station have basically been consistent since 2012, indicating that the tectonic stress field near YKO station is relatively stable or in the process of uniform stress loading; the evolution of shear-wave splitting parameters of GAX station over time is more complicated, and its fast-wave polarization direction has changed significantly before and after the small earthquake intensification in 2013. The time delay is larger than other stations, which may reflect that the crustal anisotropy below GAX station is stronger than other regions. That can provide a theoretical basis for further understanding of regional stress field characteristics and tectonic environment.
XIA Caiyun,ZHANG Zhengshuai,LIU Geng et al. Characteristics of Shear-Wave Splitting in the Crust in Southern Liaoning Region[J]. jgg, 2021, 41(2): 180-185.