芦山盆地水系与层状地貌面的构造响应及其指示意义  

TECTONIC RESPONSE OF THE RIVER AND LAYERED LANDFORM SURFACE IN THE LUSHAN BASIN AND ITS IMPLICATION

作　　者：王林[1] 李文巧[1] 苏鹏[2] 梁朋 

机构地区：[1]中国地震局地震预测研究所地震预测重点实验室,北京100036 [2]中国地震局地质研究所,北京100029 [3]中国科学院地理科学与资源研究所,北京100101

出　　处：《第四纪研究》2018年第1期165-182,共18页Quaternary Sciences

基　　金：中国地震局地震预测研究所基本科研业务费专项项目（批准号：2017IES010105、2013IES010101和2014IES010104）资助

摘　　要：基于芦山盆地之内的天全河（R1）、老场河（R2）、灵关河（R3）、西川河（R4）、沫河（R5）这5条横穿芦山地震震区河流的水系及相关层状地貌面的构造响应，反演了芦山盆地山前逆冲断层的构造运动。基于Google Earth影像、国产高分卫星数据（GF2）以及SRTM．30m的DEM地形数据，首先对水系及层状地貌面进行了遥感解译和野外考察验证，然后基于GIS平台的构建多重缓冲区、生成离散化点集以及空间投影等主要技术方法最终生成了能够反映出水系河床、层状地貌面顺河同步地形变化的综合剖面，并利用野外差分GPS实测验证了剖面图结果的准确性。综合剖面揭示出芦山盆地内的河流两侧普遍发育了5级层状地貌面，而且水系河床上主要发育着两类构造成因的裂点，第一类裂点主要沿着芦山向斜西北翼边缘的走向分布，是由于向斜西北翼相对于向斜核部的整体抬升而形成的，而第二类裂点主要在芦山向斜内部分布，是由于芦山向斜内次级活动褶皱的逆冲运动而形成的。芦山盆地内的构造裂点对层状地貌面的空间分布具有“割裂”效应，不同宽谷洼地之内的层状地貌面往往以构造裂点为界各自独立地分布。随着双石一大川断裂对芦山向斜推挤作用的增强，芦山向斜从西南部的复式向斜转变为东北部的单式向斜并直至最终尖灭，并有可能形成了一条盲逆断层，而芦山地震的发震构造应该与之密切相关。The seismogenic tectonic of the Lushan erathquake is still uncertain until now. The front of the enveloping line of the Lushan earthquake aftershocks has broken away from the main range-front fault and extended into the Lushan basin, and therefore the seismogenic fault of the Lushan earthquake may belong to the piedmont thrust fault system, but it need more evidence to prove this viewpoint further. There are 5 rivers in the Lushan basin which flow across the Lushan basin and the Lushan earthquake zone, namely the Tianquan River（ R1 ）, the Laochang River（R2）, the Lingguan River（R3）, the Xichuan River（R4）and the Mohe River（RS）. In this paper, based on the tectonic response of the drainage and layered landform surface on these rivers, we make an inversion study of the tectonic movement of the piedmont thrust fault in the Lushan basin, and try to find out the active tectonic or fault corresponding to the distribution of the Lushan earthquake aftershocks, so we can explore the seismogenic tectonic of the Lushan earthquake. Based on Google Earth online image and domestic high resolution satellite image （GF2） , firstly, we make a detailed and accurate interpretation of the 5 levels of layered landform surfaces along both sides of each river by means of remote sensing interpretation and field geological investigation, namely the first level of alluvial terrace （T1）, the second level of alluvial terrace （ T2）, the third level of proluvial terrace （ $3 ）, the fourth level of fluvioglacial terrace （$4）and the fifth level of fluvioglacial terrace （$5）. Then, based on SRTM-30 m DEM data and the powerful function of the GIS platform, we establish the multiple buffer zones, generate the discrete point sets, make the spatial projection and finally obtain an integrated topographic profile, and this kind of integrated topographic profile can reflect the synchronous topographic variation along the river flow direction of the river bed and every level of the layered landform surface at the

关 键 词：芦山向斜 水系 层状地貌面 裂点 构造响应 山前断裂 活动褶皱 发震构造 

分 类 号：P542[天文地球—构造地质学] P931.1[天文地球—地质学]