玉树断裂带左旋走滑活动标志及其几何学与运动学特征  

The geomorphologic and geological marks of the active left-lateral strike-slip fault and the characteristics of geometry and kinematics along the Yushu fault zone in southeastern Tibet

作　　者：李跃华[1,2,3] 吴中海[1] 叶培盛[1] 马丹[1,4] 刘艳辉[1,2] 蒋瑶[1,2] 李家存[4] 周春景[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]安徽地矿局第一水文工程地质勘查院,安徽蚌埠233000 [4]首都师范大学资源环境与旅游学院,北京100048

出　　处：《地质通报》2013年第9期1410-1422,共13页Geological Bulletin of China

基　　金：中国地质调查局项目(编号:1212011120163);中国地质科学院地质力学研究所基本科研业务费项目(2012-2013)(编号DZLXJK201113);国家自然科学基金项目(批准号:41171009)

摘　　要：玉树断裂带位于甘孜一玉树断裂带北西段，是一条总体呈NWW向展布的左旋走滑活动断裂带。沿断裂带发育错断水系与冲沟、拉分盆地、地震地表破裂与断裂破碎带等一系列反映玉树断裂带左旋走滑活动的典型地质一地貌标志。在室内遥感解译的基础上，结舍最新的野外实地调查成果，对沿玉树断裂带上反映其左旋走滑活动的地质一地貌标志进行了总结，并对断裂带的几何学与运动学特征进行了综合分析。结果表明，玉树断裂带总长约150kin，总体走向120-130°，自西向东可划分为呈左阶雁列分布的陇蒙达一结隆段、结隆一结古段和结古一查那扣段3段。沿该断裂带发育的串殊状拉分断陷盆地规模的大小反映出玉树断裂带自西向东拉张效应逐渐减弱、挤压效应逐渐增强的特点。玉树2010年7．1级地震的宏观震中处于晚第四纪活动性最为显著的中段，而仪器震中恰好处于该断裂带的不连续部位，进一步证明雁列走滑活动断裂带上的不连续部位通常是强震活动的初始破裂区域．Located in the northwestern part of Garze-Yushu fault zone, the Yushu fault zone is a NW-trending active left-lateral strike-slip fault. There are a series of indications reflecting the left-lateral strike-slip fault activities such as offset streams and gullies, pull-apart basin distributed along the fault zone. Based on the interpretation of satellite images and the detailed field survey and mea- surement work along Yushu fault zone, the authors systematically summarized the indicators of the active left-lateral strike-slip fault, the morphological characteristics and the kinematics marks. The results show that the Yushu fault zone strikes 120-130°in general, with clear segmentation in space. It can be divided into three left-stepped segments from west to east, i.e., Longlnengda-Jielong seg- ment, Jielong-Jiegu segment and Jiegu-chanakou segment. The scales of pull-apart basins on the fault zone indicate the characteristicsof the weakening of the tension effect and the gradual increasing of the pushing effect from west to east along the Yushu fault zone. The epicenter of Yushu 2010 earthquake lay in the discontinuous part of the fault zone, suggesting that the discontinuous zone of en echelon strike-slip faults is usually a high-risk area of seismic activity.

关 键 词：青藏高原 活动断裂 玉树断裂带 左旋走滑标志 同震地表破裂 

分 类 号：P542.3[天文地球—构造地质学]