Near-field shear-wave splitting of 2014 Yingjiang M_S6.1 earthquake sequence

SAM (systematic analysis method of shear-wave splitting) has been applied to numerous waveform data recorded by near-field mobile seismic stations of Yingjiang M_S6.1 earthquake sequence occurred on May 30， 2014. The results showed that the polarization of fast shear-wave of the earthquake sequence was consistent with regional principal compressive stress of NS trending. The polarization of fast shear-wave has a counterclockwise deflection at the station KAC， and dispersion decrease at the station MNO due to the adjustment of stress state in seismic region after the main shock. Influenced by faults of the studied area， the polarization of fast shear-wave at the station MNO presents a more discrete state compared to that of KAC. The time-delays of slow shear-wave at the stations KAC and MNO both present the feature of sudden contraction before the main shock and increase after the event， which means release and enhancement of crustal stress before and after the earthquake， and also indicates constant occurrence of aftershocks. The oscillation of time-delay curves suggests that the occurrence of aftershocks is accompanied by continuous adjustment of crustal stress in seismic region.