2013年左贡-芒康MS6.1地震序列震源机制变化过程研究

2013年8月12日西藏自治区昌都地区左贡县、芒康县交界发生6.1级地震，地震序列为前-主-余型，在主震发生前9h内发生了7次ML≥2.0中小地震，最大震级为ML 4.7。本文采用体波谱振幅相关系数方法，基于区域测震台网记录的数字地震波形资料研究左贡-芒康6.1级地震序列震源机制变化过程。结果显示，主震前的中小地震相关系数较高，均值为0.86，表明其震源机制相似程度较高，是具有震兆意义的小震序列；余震的相关系数较低，表明震源机制相似程度较低。

Study on Focal Mechanism Changing Characteristics of the 2013 Zogang-Markam MS6. 1 Earthquake Sequence

The M_S6. 1 earthquake was a foreshock-mainshock-aftershock type which occurred in the boundary region between Zogang and Markam counties on August 12,2013. Within 9hours before the main shock seven earthquakes of greater than M_L2. 0 occurred,with a maximum of M_L4. 7. In this paper,the earthquake focal mechanism changing process of the Zogang-Markam M_S6. 1 earthquake sequence is studied by calculating the correlation coefficient of body wave spectral amplitudes,and the result shows that the correlation coefficients of spectral amplitude of foreshocks present high value fluctuation with an average value of 0. 86,which shows that the focal mechanism of foreshocks are similar;and the correlation coefficients of spectral amplitude of aftershocks present low value,which shows that the possibility of a large earthquake is not high after a time.