【摘要】 利用HHT方法,对汾渭地震带1965 2011年度最大地震时间序列进行逐级分解,得到4个本征模态函数(IMF)项和一个趋势项。分析各IMF分量不同周期成分,结果显示,汾渭地震带地震活动存在比较稳定的周期,具有一定的时变性。1965年以来,在IMF1—IMF4的时间尺度上汾渭地震带M_S≥4.0地震有5个活跃期,M≥4.0地震存在3年和7年左右的活动周期,还存在16年、23年、44年左右的弱活动期。更多还原

【Abstract】 With the HHT method,the annual maximum seismic time series in Fenwei seismic zone from 1965 to 2011 are gradully decomposited,and four intrinsic mode functions(IMF) items and a trend item are obtained.The different cycles ingredients of each IMF component are analyzed.The results show that the seismic activity of Fenwei zone has stable cycle,but also has a certain time-varying.Since 1965,there are five active cycles with M_S≥4.0 earthquakes in Fenwei seismic zone in the time scale IMF1-IMF4.There are also exist activity cyclye of about three years and seven years with M≥4.0 earthquakes.There exist also 16 years,23years,44 years or so weak activity period.更多还原