中文摘要：

小江断裂带北段为白鹤滩水电站库区内规模最大的断裂构造,其几何展布特征与活动性对库区移民及其就近安置规划有明显的制约作用。通过对小江断裂北段大比例尺调查、断裂带石英形貌扫描以及现场氡气测量等综合研究,重新界定了小江断裂带北段展布,即北起宁南县华弹镇,沿金沙江左岸经永乐村,鲁吉、溜姑延伸至蒙姑以南,断裂带总体向西陡倾。石英微形貌统计分析与应力痕迹微形貌观察结果表明,断层强烈活动时间在晚更新世,同一石英颗粒表面具有代表两种滑动方式（蠕滑和黏滑）的应力痕迹组合,应力痕迹的溶蚀程度、叠加和切割关系表明,断层在晚更新世的滑动至少有3个亚期次,早期为蠕滑,中晚期为黏滑。小江断裂北段的潜在地震危险性评估表明,其可能发生强震的最大震级约在MS6.8级-MS7.1级左右,为未来仍有可能再次活动的强震地区。

英文摘要：

The northern section of Xiaojiang fault zone is the largest fracture structure in Baihetan hydropower station reservoir. Its characteristics and activities have a clear impact on migration and relocation near the reservoir.After studies of large scale investigation,fault zone quartz morphology scan and radon survey,the distribution characteristics of Xiaojiang fault zone is defined—-from north of Ningnan county,along the left bank of Jinsha River,passing Yongle,Luji,Liugu and extending to the south of Menggu. Quartz micro morphology statistical analysis and stress micro shape show that the fault activity is strong in the late Pleistocene. The facts that there are a quartz grain surface with representatives of the two sliding mode（ creep and stick slip） stress micro shape combined,the stress micro shape of corrosion degree,stacking and cutting relationship,show that the fault slipped in the late Pleistocene of at least three sub-periods,at the early stage of the creep,advanced for stick slip. The potential seismic hazard evaluation suggests that possible earthquake magnitude of northern section of Xiaojiang fault zone is MS6. 8 - MS7. 1. Therefore,there may be another strong shock in this area in the future.