中文摘要：

通过遥感影像解译和详细的野外考察,发现龙蟠—乔后断裂带剑川段晚第四纪以来长期活动,横跨断裂的水系左旋断错量可分为40 m、140 m、550 m、1040m四个等级.经详细考察后选择后菁拉分盆地开挖探槽.探槽揭示了两次M＞6.5古地震事件：一次发生在10010±40aB.P.之前;另一次发生在6130土40a B.P.和6320±40a B.P.之间.结合前人研究,分析得出剑川盆地全新世以来发生了3次M＞6.5的地震,发生时间分别为1751年、6230±130a B.P.和10737±468a B.P.,其重复间隔约为5300 a.由于1751年剑川63/4级地震相对于前两次地震释放的能量偏小,而且其离逝时间较前一次要明显长一些,故本段的地震危险性仍值得关注.

英文摘要：

Based on remote sensing interpretation, we found that the Jianchuan section of Longpan-Qiaohou fault zone has been active since late quaternary. The sinistral displace- ments of the rivers across the fault were divided into four grades of 40 m, 140 m, 550 m and 1040 m. Trench study showed that two magnitude〉6.5 paleo-seismic events were ex- posed, one of which happened before 10010±40 a B. P. , the other happened between 6130 ±30 a B.P. and 6130±30 a B. P.. Combined with previous research results, we conclu- ded that three magnitudeS6.5 earthquakes had happened in the Jianchuan basin since Hol- ocene, which happened respectively at 1751, 6230±130 a B.P. and 10737±468 a B.P. , the recurrence interval was about 5300 a. As the energy release of 1751 Jianchuan 6 earthquake is smaller than the first two and elapsed time is much longer, the seismic hazard of Jianchuan section is worthy of attention.