2008年以来滇西地区地震序列的 谱振幅相关系数变化特征

使用云南数字地震台网记录的波形数据， 计算了滇西地区2008—2011年发生的6个M_S≥4.0地震序列的谱振幅相关系数. 结果表明， 这些地震序列无论是前震型、 主震-余震型， 还是震群型地震， 其谱振幅相关系数均较高， 分析认为可能是该区域处于高应力水平状态所造成的. 谱振幅相关系数较小的地震序列， 其震源机制一致性不高， 区域应力场强度较低， 可以作为判别后续没有更大地震的指标. 前震序列的谱振幅相关系数较高， 但谱振幅相关系数较高的不一定是前震序列. 地震序列的谱振幅相关系数较高， 仅仅表明其区域应力水平较高， 这种状态有利于该区域M_S≥5.0地震的再次发生. 

Characteristics of the correlation coefficient of spectral amplitude of earthquake sequences in western Yunnan region since 2008

Using digital seismic waves recorded by Yunnan Digital Seismic Network, we calculated the correlation coefficient of spectral amplitude of six M_S≥4.0 earthquake sequences occurred from 2008 to 2011 in western Yunnan region. The results suggest that the correlation coefficient of spectral amplitude of earthquake sequences are generally high value, no matter the sequence is foreshock, main shock-aftershock or earthquake swarm, which may be caused by high stress filed in the source region. A smaller correlation coefficient of spectral amplitude, which means less consistency of focal mechanisms and low level of stress filed, can be used as an index to predict that larger earthquakes will not follow behind. The correlation coefficient of spectral amplitude of foreshock sequence is larger; however, a larger correlation coefficient does not indicate the earthquake sequence is foreshock. A larger correlation coefficient of spectral amplitude only implies high level of the stress field, but it is beneficial to occurring M_S≥5.0 earthquake in the source region.