【摘要】 南口—孙河断裂是北京平原区唯一一条北西向的活动断裂,也是张家口—渤海地震带中最醒目的隐伏、半隐伏的第四纪活动断裂。对南口—孙河断裂北西段开展了浅层地震勘探和钻探工程,验证了该目标断裂的精确定位。笔者通过钻孔岩心及探槽剖面的对比分析,并结合磁性地层研究及¹⁴C年龄测定,对该断裂第四纪以来的活动性进行了探讨。研究表明,南口—孙河断裂具有粘滑兼蠕滑的活动特点,中更新世、晚更新世和全新世以来的垂直活动速率分别为0.12 mn/a、0.58 mm/a、0.31 mm/a。总体表现为弱-强-弱的规律。晚更新世以来至少可识别出两次古地震事件,分别为距今（9230±45）aBP^9370±40aBP和（13620±90）aBP^13960±60aBP,错断地层的最浅深度为1.2 m。同时探讨了城市隐伏活动断裂的研究思路和方法。更多还原

【Abstract】 As one of half-buried and buried faults in Quaternary in Zhangjiakou-Bohai seismic belt,Nankou-Sunhe fault is the unique NW-striking active fault in the capital circle.Based on shallow seismic method and borehole engineering,the authors precisely determined the position of the northwest section of Nankou-Sunhe fault.Contrastive analysis was made with drilling core and trench profile,combined with the study of magnetic stratigraphy and 14 C dating data.The authors explored the activity of the northwest section of Nankou-Sunhe fault since late Pleistocene.Researches show that the activity of Nankou-Sunhe fault has both stick-slip and creep-slip properties,and the vertical activity rate of the fault was 0.12 mm/a in middle Pleistocene,0.58 mm/a in late Pleistocene,and 0.31mm/a in Holocnene.The fault’s active characteristics show complete regularity,i.e.,s from weak to strong,then to weak.At least two earthquake events can be recognized since the late Pleistocene,with their ages being(9230±45)aBP-(9370±40)aBP and(13620±90)aBP-(13960±60)aBP respectively and the least active displacement fault depth being 1.2m.The authors also explored the research thinking and methods for buried active faults in cities.更多还原