STUDY ON THE CORRELATION OF SPECTRAL AMPLITUDE OF SEVERAL SEISMIC CLUSTERS IN SHAANXI AND ADJACENT AREAS

Basing on four small seismic clusters occurred near Ningqang,Huozhou,Yinchuan and Gulang areas since the 2008 Wenchuan Ms8.0 earthquake,the correlation coefficient changes with time of spectral amplitude of each earthquake cluster sequence is calculated by the new method of correlation analysis of spectral amplitude,and the risk of strong earthquake in each sequence region is analyzed.The results show that the correlation coefficient of spectral amplitude of the Huozhou seismic sequence is higher than others,thus the stress level,the consistency focal mechanism of small earthquakes,and the risk of subsequent strong earthquakes near the Huozhou area is higher.The spectral amplitude correlation coefficient of other three regions is lower,indicating that the stress level of these three areas is not high,the consistency focal mechanism of small earthquakes is not high,and the risk of subsequent strong earthquakes is lower.