维西-乔后断裂晚第四纪活动、滑动速率及其在川滇块体西边界构造演化中的作用

项目名称： 维西-乔后断裂晚第四纪活动、滑动速率及其在川滇块体西边界构造演化中的作用

项目编号： No.41472204

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 常祖峰

作者单位： 云南省地震局

项目金额： 103万元

中文摘要： 川滇块体为青藏高原东缘长期强烈活动的块体，边界断裂带上历史地震活动频繁。汶川8级大地震的发生，更加警示人们重点关注块体边界断裂活动性和地震危险性的研究。维西-乔后断裂位于川滇块体西部边缘，南与红河断裂相连，北与金沙江断裂相接，是连接南、北两条活动断裂(红河和金沙江断裂)的桥梁。本项目拟在已开展的预研究基础上，结合高分辨率遥感影像和航空遥感图像解译，借助精细的地貌测量、槽探、年代样品测试等方面的工作，研究断裂的最新活动时代、滑动速率、活动特征及其古地震复发间隔等，评价未来强震的危险性；研究分析断裂构造地貌特征及演化历史、断裂活动的起始时代；分析晚新生代以来构造形迹特征和区域构造应力场演变；探讨其与红河断裂和金沙江断裂的关系，断裂在川滇块体西边界构造演化中的作用和影响。研究成果对合理评估川滇块体西边界断裂的强震危险性，对探讨青藏高原东南缘现今动力学环境、块体边界构造变形具有重要理论和实际意义。

中文关键词： 维西-乔后断裂；晚第四纪；滑动速率；古地震

英文摘要： Various models are proposed to describe the tectonic evolution and uplift of the Tibetan plateau. Sichuan-Yunnan block lies to southeastern boundary of the eastern Himalayan syntaxis (EHS), and is strongly active for a long term, with intense earthquake having occurred frequently along the boundary faults of the block historically. That the Wenchuan Magnitude 8.0 earthquake occurs warn people to focus on the block boundary study on faults activity and seismic risk to a higher degree. The Weixi-Qiaohou fault is located at the western margin of Sichuan-Yunnan block, connecting to the Red riverI fault in the south and to the Jinsha river fault in the north, respectively, is the bridge between the north and the south active faults. On the basis of pre-research, combining the interpretation on the Satellite images figures and aerial photographs, this project aims at the study on the latest active time, the slip rates, the activity features, Paleo-earthquake recurrence interval, etc., and appraising the future seismic risk of large earthquake, by approach of precise topographic measuring by equipments, such as Trimble 5800 GPS, Geological mapping with a large scale, such as 1:5,000～10,000, field investigating, trench excavating and chronology testing. Study on the tectonic topographic characteristics and evolution history, the active inception, the relationship of tectonic deformation style and the regional tectonic stress field evolution characteristics since late Cenozoic will be conducted as well. The purpose of the study is to acquire a complete and reliable understanding of active features of the Weixi-Qiaohou fault in late Cenozoic, to explore the relationship of the fault with the Red river fault and with the Jinsha river fault ,and to assess the role and influence of the fault in the tectonic evolution of the western boundary of Sichuan-Yunnan block. The research result has both theoretical and practical meanings on assessing reasonably the strong earthquakes risk along the western boundary faults of Sichuan and Yunnan block, on discussing the present dynamic circumstances around the southeastern Tibetan plateau and the boundary tectonic deformation style patterns.

英文关键词： Weixi-Qiaohou fault;Late Quaternary;Slip rate;Paleo-earthquake