2014年安徽金寨 ML3．9震群序列震源一致性研究

摘要

The Jinzhai ML 3.9 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 ampli-tude 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 ML 3.9.And the polarity of first motions of 115 earthquakes with ML ≥1.5 recorded by three stations close to the earth-quake 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 polari-ties of first motion recorded by stations are also consistent.All mentioned above suggests that the consistency parameters of focal mechanism of Jinzhai earth-quake sequence are in a very high degree.%首先采用 P 波、SV 波和 SH 波的极性和振幅比联合求解2014年安徽省金寨 ML 3．9震群序列的震源机制解，并在此基础上计算得到该震群序列的震源一致性参数和 P 轴方位角随时间的变化；然后基于震区附近3个台站记录到的该震群序列的地震波形，计算其体波谱振幅相关系数，同时读取震区附近3个台站记录到的该震群序列中115次 ML ≥1．5地震的极性．研究结果表明：金寨 ML 3．9震群序列的地震震源机制解绝大多数为压性走滑型，P 轴方位角较为一致；其震源一致性参数处于较低水平，体波谱振幅相关系数较高；台站所记录到的地震极性也较为一致．该结果表明金寨 ML 3．9震群序列的震源一致性程度非常高．