用地震活动多参数扫描法探测汶川地震孕育的临界信息

Variation of multiple seismicity parameters usedtoinvestigate critical behavior of the Wenchuan earthquake preparation

摘要: 采用时间扫描方法，通过能量释放率、b值、空间相关距离和广义维等多种统计参数的协同分析，研究了汶川8.0级大地震及其多次强余震之前区域地震活动性随时间的变化特征，发现大震前的地震活动表现出能量释放率增大，b值的大幅度减小，空间相关距离的下降和广义维的下降和回升等异常特征．对后续余震活动的分析，也可分辨出地震活动的临界异常特征．结果表明，多种统计参数的综合协同分析能够反映地震活动的特点，发现孕震系统激变前的临界行为．

Abstract: On the basis of analyzing multiple statistical parameters, including cumulative energy release, b-value, spatial correlation length and fractal dimension, temporal variation of regional seismic activity before the 2008 Wenchuan earthquake and its large aftershocks were studied with time scanning approach. Some abnormal variations are found, including obvious increase of cumulative energy release, decrease of spatial correlation length and fractal dimension, and appearance of low b-value. A similar characteristics is found in aftershock activity. The result of this study indicates that using multiple seismic parameter analysis we can trace back the critical state of the Wenchuan earthquake preparation.