安徽地区地震活动趋势分析

安徽地区地震活动周期表将公元２８８ 年以来Ｍ≥４ ．０ 地震活动划分为与华北二至七周期相对应的六个地震周期，每周期分为与华北相似的初震段、前震段、主震段和余震段四个地震段。安徽地震周期超前于华北地震周期，每周期４ 级以上地震从皖渐交界一带的皖东南地区开始活动，各阶段最大地震震中由南向北迁移。第七周期４ 级以上地震活动至１９７９ 年固镇５ 级地震已结束，未来将进入第八周期初震段。近几年皖东南地区的广德县或旌德县可能发生４－３ 级左右地震。

TENDENCY ANALYSIS OF SEISMIC ACTIVITY IN ANHUI AREA

There are six periods of M S≥4.0 earthquakes since A.D. 288 in the seismicity period table of Anhui area, corresponding to 2～7 periods of north China seismicity. The period has four stage of primal shock, foreshock, mainshock and aftershock as north China. The Anhui seismicity period precedes north China one. The seismicity of M S≥4.0 earthquakes of every period begins in the eastsouth area of Anhui conjugated with Zhejiang, and the epicenters of maximum earthquakes immigrate from south to north. Seventh seismicity period had ended, and eighth period began until Guzheng earthquake of M S 5.0 occurred. An earthquake of M S 4.3 will can occur in the Guangde or Shengde county of eastsouth Anhui area in several years of furture.