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

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.