Abstract: The 4 paleoearthquake events that have occurred on seismogenic fault of 1679 Sanhe Pinggu M8 Earthquake since 20ka B.P. are exposed through the analysis of trenches and fault scarp profiles. The earlier two events are marked by liquefaction and the later two events are shown by direct fault offset,including the 1679 event. The 1679 event and pre 1679 event are two characteristic earthquakes of which the maximum displacement is about 1.75m and 1.41m,respectively and the intensity of two events is very close. The occurrence time of 4 events was about 20000,13000,7500 and 317a B.P.,respectively. Average interval of recurrence is (6561?691)a. It indicates the characteristics of quasi- periodic occurrence of earthquakes.

Key words: Sanhe-Pinggu earthquke, Paeoearthqake, Earthquake recurrence interval

摘要： 通过大探槽开挖和断层陡坎分析,揭示出发生于1679年8级地震的新夏垫断层自距今约2万a以来共发生了4次地震事件。前两次为砂体液化显示的事件;后两次为可见直接断错证据的事件。分析得到的1679年地震最大垂直位移为1.75m,前1679年事件为1.41m,是两次震级非常接近的特征地震。4次事件发生的时间分别为距今约20000,13000,7500和317a,平均重复间隔时间为(6561±691)a,显示了准周期重复的特征。

关键词: 三河－平谷地震, 古地震, 地震复发周期