【摘要】 采用Aki的单次散射模型计算了广东阳江地区2003年10月至2007年5月尾波Qc值,流逝时间为24~27 s、28~31 s、38~44 s的Qc值平均值分别为95、115和124。2004年9月17日阳江4.9级地震前后,流逝时间较短的两个Qc值变化较为同步,Qc值出现"低值—回弹—发震—低值"演化过程,而流逝时间38~44 s的Qc值在整个研究时段内未出现显著异常过程。研究表明,Qc值对地震序列发展的监测是有效的,前兆异常信息的获取与流逝时间的选取具有较大的相关性,对于广东阳江地区,作为前兆监测手段的Qc值,其流逝时间在24~31 s较为合适。更多还原

【Abstract】 In this paper,based on the single scatter model(Aki),Coda Q_c was calculated from May 2003 to May 2007 in Yangjiang area,Guangdong Province,using vertical digital seismic wave recorded by Yangjiang earthquake station whose epicenter distance between 7 to 30 km.The average of Q_c with 24~27 s of elapsed time windows was 95,and 28~31 s is 115,and 34~44 s is 124.The M4.9 Yangjiang earthquake occurred on September 17,2004.The temporal characteristics of Q_c between 24~27 s and 28~31 s of elapsed time windows show rough agreements from Feb.2004 to Dec.2004.Q_c would trend to decrease at first about half a year before the main shock occurred,then increased,a short time after the main shock occurred,Q_c would trend to decrease to the normal value 2~3 months after the main shock occurred.Q_c with 38~44 s of elapsed time windows didn′t appear anomalous change.Q_c is an effective mean to observe the evolvement of earthquake sequence and predict the main shock,but the key point is how to select the length of the elapsed time windows.As an observational mean for seismic precursor,the elapsed time windows of Q_c should be about 24~31 s for Yangjiang areas.更多还原