昭通——鲁甸断裂带晚第四纪活动性研究

昭通—鲁甸断裂带是青藏高原东南缘大凉山次级活动块体南部边界的重要组成部分，也是滇东北地区重要的地震构造.为进一步了解断裂活动程度和晚第四纪活动性，开展野外地质地貌调查、探槽工程及样品采集与年代学测试等研究.结果表明：(1)根据野外地质地貌调查结果，昭通—鲁甸断裂带北东向3支次级断裂在晚更新世以来活动强烈，运动性质以逆冲兼具右旋走滑为主.(2)昭通—鲁甸断裂上，新棚子村开挖的探槽揭示出断层错断了晚更新世地层（32 510±30）a BP]；根据黏土层明显的砾石定向排列及砂石层扰动现象，推测断层可能错断全新世地层（10 880±30）a BP].研究成果对滇东北及川滇交界地区地震趋势及地震危险性预测具有重要意义.

Research on Late Quaternary activity of Zhaotong-Ludian fault zone

Zhaotong-Ludian fault zone is an important part of the southern boundary of Daliangshan secondary active block on the southeast margin of Qinghai-Tibet Plateau, and it is also an important seismic structure in Northeast Yunnan. In order to further understand the degrees of fault activities and late Quaternary activities, field geological and geomorphological investigations, trenching engineering, sample collections and chronologic tests were carried out. The results were as follows: ① According to the field geological and geomorphological survey results, three secondary faults in the northeast of Zhaotong-Ludian fault zone had been strongly active since the late Pleistocene, and their movement characteristics were mainly thrust and dextral strike-slip; ② The exploratory trench excavated in Xinpengzi Village of Zhaotong-Ludian fault revealed that the fault dislocated the Late Pleistocene strata (32510±30) a BP]. According to the obvious directional gravel arrangements in clay layers and the disturbance of sandstone layers, it was speculated that the fault may have dislocated the Holocene strata (10880±30)] a BP]. To sum up, the research results are of great significance for the prediction of earthquake trend and earthquake risk in Northeast Yunnan and Sichuan-Yunnan border areas.