Preliminary study of seismic anisotropy in Qianguo area, Jilin province

A series of earthquakes happened in November 2013 in Qianguo area, Jilin Province. Using the seismic data recorded by 6 temporary stations from November 1 to 24, with the method of shear-wave splitting, this paper preliminarily determines the polarization directions of fast shear-wave and the time-delays of slow shear-wave, and discusses the distribution of stress in the crust. The polarization direction of fast shear-wave is mainly NW and NE. On the whole, the consistency of NW direction is better, but the results in NE direction are somehow scattered, which suggests the complexity of the stress in the study area. The anisotropic direction of NW which is in agreement with the spatial expanding direction of earthquakes, is vertical to the strike of seismogenic fault. The NW direction of fast shear-wave is the same as the direction of surface velocity field. The polarization direction of fast shear-wave is consistent with the thrust and strike-slip focal mechanism solution. The time-delay of slow shear-wave is in the range of 0.85 similar to 6.93 ms/km. The characteristic changes before and after the M(s)5. 3, 5. 8 earthquake reflect the accumulation of the crustal stress and decrease after the earthquake happening.