2014年10月7日21时49分,云南省普洱市景谷傣族彝族自治县发生M_W6.2级地震.为了更好的认识本次地震的发震构造和震源运动学特征,我们利用IRIS上下载的远震P波数据和格点搜索的方法反演得到本次地震震源机制.为了对反演结果进行进一步验证,本文选用了当地台站提供的近震数据,利用双差定位的方法进行了重定位研究,地震重定位的结果和震源机制的反演结果有较好的一致性.反演结果得到节面1走向为240°,倾角87°,滑动角12°;节面2走向149°,倾角78°,滑动角177°.再结合双差定位后地震群的分布,最终确定节面2为本次地震的发震断层.对比之前云南地区断层分布推断本次地震的发震断层为新的隐伏断层.
An M_W6.2 earthquake occurred in Yunnan Pu’er Jinggu Dai and Yi Autonomous County at 21: 49 on October 7,2014. For a better understanding of the source mechanism and the character of the source kinematics,we used teleseismic P-wave data downloaded from IRIS and utilized the grid search method to invert the source mechanism. The near-field seismic data provided by local stations are employed to relocate the location of the event by the doubledifference method,which compares well with the results of the focal mechanism inversion. The inversion result shows that the strike of one nodal plane is 240 °,the dip angle 87 °,and the rake 12 °,and that for another nodal plane the strike is 149 °,the dip 78 °,the rake 177 °. With the combination of the inversion result and the distribution of earthquake swarm determined by relocation, we ultimately concluded that the seismogenic fault plane is the second nodal plane. According to the fault distribution of the area,the seismogenic fault of this earthquake may suggest a new concealed fault.