Consistency parameters of focal mechanism for the M_L3.9 Jinzhai, Anhui, earthquake swarm sequence in 2014

The Jinzhai M_L3.9 earthquake swarm sequence occurred in Guanmiao town, Jinzhai county, Anhui Province in 2014, which continued in high activity frequency for a long duration. The focal depths of earthquakes in Jinzhai swarm were all shallow and the region was about 5 kilometers. Firstly, the consistency parameters of focal mechanism and the change in P-axis azimuth with time for the Jinzhai sequence have been obtained from the focal mechanism data which were solved by combining the polarity of P, SV and SH waves with their amplitude ratios. Then the correlation coefficients of spectral amplitude of the Jinzhai sequence were calculated based on the seismic waveforms recorded by three stations near the epicenter of Jinzhai M_L3.9. And the polarity of first motions of 115 earthquakes with M_L≥1.5 recorded by three stations close to the earthquake region had been read at the same time. The results show that the main type of focal mechanism of Jinzhai earthquake swarm sequence is transpressional strike-slipping， and the P-axis azimuth is more consistent for the earthquakes. The consistency parameters of focal mechanism are at a low level, while the correlation coefficient of spectral amplitude are relatively high, and the polarities of first motion recorded by stations are also consistent. All mentioned above suggests that the consistency parameters of focal mechanism of Jinzhai earthquake sequence are in a very high degree.