北京平原区夏垫活动断裂滑动速率及古地震复发间隔

The Slipping Rates and Ancient Earthquake Recurrence Interval at Xiadian Fault,Beijing Plain

搜集了有关夏垫断裂钻孔测年数据,采用最小二乘法对数据进行拟合分析,拟合结果显示夏垫断裂滑动速率在地段和时段上均存在差异,且在时段上的差异更加明显。前20 ka以来滑动速率相对较小(0.13~0.30 mm/a);前26 ka^20 ka,滑动速率较大(1.38~2.56mm/a),约为前20 ka以来滑动速率的9~11倍。利用潘各庄探槽、东柳河屯探槽、齐心庄探槽、大胡庄探槽、地震联合钻孔剖面及钻孔资料判定除1679年三河-平谷8级地震外,前20 ka以来夏垫断裂还存在6次古地震事件,古地震平均复发间隔约为3 000 a。

In this study some drilling dating data of Xiadian fault are collected. Using the least squares analysis to fit the data, the results show that the Xiadian fault slip rate is different in location and time. Slipping rate difference in time is more apparent. Since 20 ka the slipping rate is relatively slow and is about （0. 13 ～ 0. 30） mm/a; （26 ～～ 20） ka slipping rate is quicker and is about （ 1.38 - 2.56） mm/a, about 9 - 11 time as the slipping rate since 20 ka. The frequency and time of the ancient earthquake events are analyzed by making use of Pangezhuang trench, Dongliuhetun trench, Qixinzhuang trench, Dahuzhuang trench, seismic drill logs and drilling data. The results revealed that Xiadian fault had another 6 ancient earthquakes besides the M8 earthquake happened in Sanhe-Pinggu of 1679 since 20 ka. The average recurrence interval of ancient earthquakes in Xiadian fault is speculated as 3000a according to these ancient earthquake events recurrence intervals.