Abstract: Since the Zemuhefaultrejuvenated asthetransition faultbetween the Anninghefaultandthe Xi aojiang fault aboutin the Middle Pleistocene,it was dominated bystrongleftlateralslip and becameanim portantearthquakefault.Thelowestalluvialfantableland,which developed widespreadinthe Zemuhe val ley,isestimated to be 10 000 ～15 000 years BPbased on thermoluminesceneand 14Cdatingresults.Sever alfaulted streams, which cutthesurface ofthelowesttableland and should be youngerthan orasold asthe lowesttableland,areselected to belandform feature for determining the net tectonic displacement on the Zemuhefault and were surveyed. The average displacement of these streams was measured to be 86m. Therefore,the averagelateralslip rate of Zemuhefaultin the Late Pleistoceneis calculated to be 5.8 ～8.6m m/a.

Key words: Fracture Zone, Microfaulted landform, Topographicsurrey, Strike slip rate

摘要： 则木河断裂带南北分别与安宁河断裂带和小江断裂带相接,自中更新世复活以来,以左旋走滑为主,并成为一条重要的地震断层。据TL和ESR 测年分析,则木河谷地广泛存在的最低一级冲积扇为10000 ～15000 年以来形成。切割这些冲积扇的冲沟被则木河断裂带错断,其发生时间与冲积扇相当或者更新,平均位移值测量为86m.据此计算,则木河断裂带晚更新世以来的平均走滑速率为5.8 ～8.6mm/a.

关键词: 断裂带, 微断层地貌, 地形测量, 走滑速率