【摘要】 运用小波变换方法,以不同的小波时间尺度分析了华北地区1480~2009年M≥5.0和1970~2009年M≥4.0地震的贝尼奥夫应变数据,得到了不同时间尺度的地震活跃期和平静期。分析表明:目前华北地区从1480年以来的M≥5.0地震活动刚过活跃期,处于应力积累阶段,而1970年以来M≥4.0地震存在7年左右的活动周期,目前正在进入4级以上地震的活跃期。更多还原

【Abstract】 Referring to the M≥5.0 earthquakes from 1500 to 2000 and the M≥4.0 earthquakes from 1970 to 2009 in North China,we analyze the Benioff strain using wavelet transform in various scales.Analysis shows that on a century-scale the M≥5.0 earthquake-activity period has just finished and now the stress is accumulating.And since 1970 there has existed activity cycle of about 7 years for the M≥4.0 earthquakes;now the M≥4.0 significant earthquake-activity period is beginning in North China.更多还原