The bulk of the crustal shortening across the Himalayas is accommodated across the Main Frontal Thrust (MFT), forming the topographic ridges of the Siwalik Hills. Here, we quantify topographic metrics to document the geomorphic response to progressive shortening. We use the integral method of channel profile analysis to assess the topographic response to the development of thrust anticline ridges in the eastern and western Churia, Dundwa, and Mohand Ranges. River channel steepness (k_sn), the distribution of knickpoints, and channel concavity (θ) in the Siwalik Hills indicate geomorphic evolution during ongoing shortening across the deformation front. Mean channel steepness indices increase with increasing shortening over the Quaternary amongst the eastern Churia (~3.8 km shortening), Mohand (~6.9 km shortening), and Dundwa Ranges (~9 km shortening). Higher channel steepness at the western tip of the Churia Range (~0.4 km shortening) than in the eastern Churia and Mohand Ranges may indicate that the topography is still responding to the initial stages of shortening and relative uplift. Balanced cross sections reveal that there is spatial variability in the growth of these ranges, and as shortening increases, the drainage divide migrates southward (away from the mountains) relative to the flat-ramp transition of the underlying thrust; this results in steepening of the southward-draining catchments (basinward facing), and elongation of the northward flowing catchments. Basinward facing channels also have more prominent knickpoints and greater channel concavities caused by ongoing shortening between their fluvial base level and the drainage divide; this contrasts with the mountain facing channels where there is net growth of the distance between the drainage divide and the base level. Despite the asymmetry of erosional processes, the southward displacement of the drainage divide over the underlying thrust ramp drives topographic advection into the foreland succession which eventually leads to the propagation of new thrust-cored ridges.

整个喜马拉雅山脉的地壳缩短部分被容纳在主前冲断层（MFT）中，形成了Siwalik Hills的地形脊。在这里，我们量化地形指标以记录对渐进缩短的地貌响应。我们使用通道剖面分析的积分方法来评估东部和西部Churia，Dundwa和Mohand山脉对逆冲背斜脊发育的地形响应。河道陡度（k _sn），拐点分布和河道凹度（θSiwalik Hills中的）表示整个变形前沿持续缩短期间的地貌演化。在东部Churia（缩短了约3.8 km），Mohand（缩短了约6.9 km）和Dundwa Ranges（缩短了约9 km）之间，第四纪平均河道陡度指数随着缩短的增加而增加。Churia山脉西端（缩短约0.4 km）比东部的Churia和Mohand山脉具有更高的河道陡度，这可能表明地形仍在响应缩短和相对隆起的初始阶段。平衡的横截面表明，这些范围的增长存在空间差异，并且随着缩短的增加，排水沟相对于下伏逆冲的平坦坡道过渡向南（远离山脉）迁移。这导致向南排水的流域（朝北的面）陡峭，向北流动的流域拉长。面向盆地的河道还由于其河流基面高度和排水沟之间的持续缩短而引起了更大的拐点和更大的河道凹度。这与面向山的渠道形成对比，在这些渠道中，排水沟和基准面之间的距离净增长。尽管侵蚀过程是不对称的，但排水流向南的位移在下伏的逆冲坡道上驱使地形对流进入前陆演替，最终导致新的逆冲芯隆起的传播。面向盆地的河道还由于其河流基面高度和排水沟之间的持续缩短而引起了更大的拐点和更大的河道凹度。这与面向山的渠道形成对比，在这些渠道中，排水沟和基准面之间的距离净增长。尽管侵蚀过程是不对称的，但排水流向南的位移在下伏的逆冲坡道上驱使地形对流进入前陆演替，最终导致新的逆冲芯隆起的传播。面向盆地的河道还由于其河流基面高度和排水沟之间的持续缩短而引起了更大的拐点和更大的河道凹度。这与面向山的渠道形成对比，在这些渠道中，排水沟和基准面之间的距离净增长。尽管侵蚀过程是不对称的，但排水流向南的位移在下伏的逆冲坡道上驱使地形对流进入前陆演替，最终导致新的逆冲芯隆起的传播。