【摘要】 2008年5月12日龙门山发生了8.0级特大地震,仅仅时隔5年,在2013年4月20日,龙门山构造带南段又发生了M7.O级地震,说明该区域构造运动频繁发生,也因此成为地质地貌学家研究构造一地貌一水系的理想场所。构造活动对河流的发育、形态（纵剖面形态、平面形态、三维地貌）等有重要影响。基于DEM数据,本文提取了龙门山中段山前地区的湔江（R₁）、金河（R₂）、绵远河（R₃）、干河子（R₄）和安昌河（R₅）5条河流及其次流域,分别计算了5条河流的Hack剖面、河长坡降指标（sL参数）以及标准化坡降指标（SL/K）等构造地貌参数,并计算了这5条河流及其次流域的面积一高程积分值,对该地区的构造活动、地貌演化特征进行分析。研究表明:1)龙门山中段山前地区5条河流的Hack剖面皆呈上凸形态,表明龙门山中段山前地区处于构造抬升状态;2)该地区的sL参数主要反映的断裂构造活动信息,sL参数在映秀-北川断裂峰值最为明显,说明该地区该断裂的活动性最强;3)龙门山中段的5条河流面积一高程积分线接近凹形,该地区地貌演化整体上处于"壮年期"向"老年期"过渡阶段;4)龙门山中段山前地区构造活动性在空间上有差异性,该地区的中南段活动性较强,北段地区活动性较弱。更多还原

【Abstract】 The Mt.Longmenshan is located at the eastern margin of the Qinghai-Tibetan Plateau.It is not the one which has the greatest transmutation of steepness among those around the Qinghai-Tibetan Plateau,but also one of the areas where the strongest climate and tectonic activities have been happened.In recent years,the apparent seismic activity around the Mt.Longmenshan has included the Wenehuan Earthquake（magnitude 8.0）and the Lushan Earthquake（magnitude 7.0）,occurring in 2008 and 2013,respectively.Thus,this area has been one of the best places to study the relationships about tectonic-geomorphy-water system.Tectonic activity has important influence on stream development and shape（including shape of longitudinal profile,plane configuration,three dimension landforms）.The paper has extracted the drainage basins of 5 rivers,which they are Qianjiang River（R₁）,Jinhe River（R₂）,Mianyuanhe River（R₃）,Ganhezi River（R₄）and Anchanghe River（R₅）in the middle segment of Mt.Longmenshan,and their sub-drainage basins by using GIS technology.Hack Profile,SL Index（SL）and Gradient Index（SL/K）are examined for concavity studies of each profile and withdraw hypsometric integral from5 drainage basins and their sub-drainage basins.By the analysis of above parameters,we state that Convex Hack profile of 5 rivers shows that piedmont drainage basins of the middle Mt.Longmenshan is in the stage of tectonic uplifting in the Cenozoic.The river segments with abnormally high SL values,which mainly represented faults activity of study area.The obviously high SL values appear in Yingxiu-Beichuan fault,which shows the strongest activity of the fault zone.It is transitional stage in "manhood" and "old age",because of hypsometric curves of 5rivers from S-shaped to concave development in the piedmont of middle Mt.Longmenshan.However,the tectonic processes are distinguished in the study area,which tectonic activities are declining from the middle-south to northwest segment along the piedmont of middle Mr.Longmenshan.更多还原