【摘要】 用统计学上的χ~2检验方法对华东地区M_L≥4.0地震平静进行了统计检验,得出在较高的置信概率下可以将平静时间T≥140天作为平静异常的判别标准。总结了华东地区自1970年以来出现的平静异常,并分析了其对应中强地震的情况。研究表明,M_L≥4.0地震平静异常是华东地区中强震前的一种普遍现象。62.5%的平静异常后发生了M_S≥4.5地震;绝大多数平静异常前存在着地震活动的增强过程,多次活动增强后连续发生了平静异常且之后发生了M_S≥5.0地震。更多还原

【Abstract】 In this article, we use the examination method to give statistic and examination of M_L≥ 4.0 earthquake quiescence in East China.We get the conclusion that if the quiet time of M_L≥4.0 earthquake is more than 140 days, it can be regarded as an abnormity with high probability.We summarized the M_L≥4.0 earthquake quiescence abnormity in East China since 1970 and analyzed the subsequent mid-strong earthquakes.It can be found that there were earthquake quiescence abnormity before most mid-strong earthquakes in East China. After a quiescence abnormity, in most cases (62.5%) , an earthquake of M_S≥4.5 will occur. Before most quiescence abnormity, there is an activity abnormity.Many times after an activity abnormity, continuous quiescence abnormity occurs and then an earthquake of M_S≥5.0 happens.更多还原