Controls on the regional distribution of landslide dams and implications for fluvial landform evolution in Bhutan and its surrounding area  

作　　者：ZHANG Qi-yuan HU Kai-heng LIU Shuang LIU Wei-ming 

机构地区：[1]Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(CAS),Chengdu 610041,China [2]University of Chinese Academy of Sciences,Beijing 100149,China [3]China-Pakistan Joint Research Center on Earth Sciences,Islamabad 30001,Pakist

出　　处：《Journal of Mountain Science》2023年第8期2107-2132,共26页山地科学学报（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.91747207);the National Key R&D Program of China(Grant No.2018YFC1505205);the National Natural Science Foundation of China(Grant No.41790434)。

摘　　要：The regional distribution of landslide dams can provide valuable insights into the interactions among various factors,including lithology,topography,climate,and fluvial landforms in tectonically active mountains.Himalayan rivers are frequently impacted by large-scale landslide damming,which profoundly influence fluvial geomorphology.In this study,we identified 1652 landslide dams in four major rivers of Bhutan and its surrounding area by remote sensing interpretation.Notably,approximately 71%of these landslide dams are found in regions composed of quartzite or gneiss.Fault-related tectonic activity plays a significant role in governing the distribution of these landslide dams,as approximately 83%of the mapped landslide dams are found within a 10 km radius of the nearest fault.The majority of the identified landslide dams are situated in areas with relatively modest local relief,ranging from 227 m to 327 m.These dams tend to cluster in the tributaries,and the stream power of almost 95%of them is typically below 1×10^(6) kg m^(2) s^(-3).Our data,combining the erosion rate and kernel density map of the landslide dams,reveals that regions with high erosion rates do not consistently align with the major high-density distribution of landslide dams.It is shown that the distribution of landslide dams is strongly influenced by the valley form.In comparison to U-shaped valleys,V-shaped valleys exhibit a higher density of landslide dams.Intriguingly,we also find a positive correlation between the landslide-dam distribution density and the erosion rate only in relatively arid regions with mean annual rainfall less than 500 mm.Moreover,the length of the upstream reach protected by the knickpoint associated with both lithology and landslide damming is about three times longer than that protected by the knickpoint associated only with landslide damming.

关 键 词：Bhutan Himalayas Landslide dams Erosion rate Geomorphological impacts Landscape evolution 

分 类 号：P642.22[天文地球—工程地质学] P931.1[天文地球—地质矿产勘探]