东昆仑断裂东段玛沁—玛曲段几何结构特征  

THE SEGMENTAL CHARACTERISTICS OF GEOMETRICAL STRUCTURE OF THE EAST KUNLUN ACTIVE

作　　者：李陈侠[1,2] 徐锡伟[1] 闻学泽[3] 郑荣章[1] 陈桂华[1] 

机构地区：[1]中国地震局地质研究所,国家地震活动断层研究中心,北京100029 [2]中国地震局兰州地震研究所,兰州730000 [3]四川省地震局,成都610041

出　　处：《地震地质》2009年第3期441-458,共18页Seismology and Geology

基　　金：国家科技支撑计划项目(2006BAC13B0120101);国家自然科学基金(40474037)资助

摘　　要：文中主要通过ETM,Quickbird,Worldview卫星影像解译,利用断裂带的几何、构造不连续点,对东昆仑断裂带玛沁—玛曲段进行几何分段。自西向东可分为东倾沟段、大武滩段、肯定那段、西科河段、唐地段、玛曲段、墨溪段和罗叉段,前7条断裂羽列排列,唐地段和玛曲段为右阶排列,其余为左阶排列,各阶区之间范围较小,联系紧密。最大的阶区长10km,宽1.3km。除了阶区,断裂的分段标志还有走向的弯曲与断裂的交会。东倾沟段和罗叉段的分段标志主要为断裂走向的弯曲,最大的走向弯曲为东倾沟段,为34°的右阶挤压弯曲。在莫哈汤南侧东昆仑断裂与阿万仓断裂交会,为西科河段的1个分段标志。该段广泛分布的构造地貌和古地震造成的破裂标志表明该段曾经历过多次活动。断裂带从NW向SE呈帚状散开,结合不同段上的滑动速率,发现东昆仑断裂东段滑动速率呈梯度下降与东昆仑断裂带东段帚状散开的几何特征一一对应。The paper carries out geometric segmentation of the eastern segment of East Kunlun Active Fault （Maqin-Maqu segment）based on the interpretation of ETM and QuickBird satellite images and using segmental signs of strike-slip fault, such as geometric and tectonic discontinuities in combination of geomorphic features and fault zone materials. In this study,we divide the Kunlun Active Fault（ Maqin- Maqu segment） into eight segments, geometrically, namely, Dongqinggou, Dawutan, Kendingna, Xikehe, Tangdi, Maqu, Moxi and Luocha. Faults in the former seven segments are developed en echelon, of which ,that in the Tangdi and Maqu segments are of right-stepping en echelon, and the rest are of leftstepping. The space between steps is small and well-connected. Beside the stepover,the segmentation indicators also include the bend of fault strike and the intersection of fault with others. Luocha segment is divided mainly by the strike bend. The east Kunlun Fault intersects with the Awancang Fault and Xikehe-Maqu Fault at the south side of Mohatang,which is taken as an indicator of segmentation of the Xikehe segment. The extensive landform and evidence of paleo-seismic rupture indicate that the Maqin-Maqu segment has experienced numerous movements. The fault splays out from northwest to southeast,which has good correlation with the slip rate gradients along the Eastern Kunlun Fault.

关 键 词：东昆仑断裂带 几何结构特征 分段标志 阿万仓断裂 玛沁—玛曲 

分 类 号：P315.2[天文地球—地震学]