喜马拉雅山脉地震带主要地质灾害与地形地貌关系——以西藏日喀则地区为例

喜马拉雅山脉是欧亚板块和印度洋板块挤压碰撞形成的巨大山脉，历史上曾多次发生7级以上地震，引发大量次生地质灾害。收集以往资料，结合野外调查和遥感解译，利用喜马拉雅山脉地震带（日喀则段）地貌图和GIS的数据管理与空间分析功能，对日喀则地区主要地质灾害进行分析，绘制地质灾害分布图和密度等值线图。结果表明：①研究区主要地质灾害集中分布，共5个集中区；②主要地质灾害发育于侵蚀剥蚀大起伏高山和冰缘作用的大起伏极高山地貌，河谷平原及冰碛丘陵次之，其他地貌特征发育灾害较少；③滑坡、崩塌灾害易发于海拔3500 m以下阳坡（90°~270°），在南东向敏感性最强，滑坡、崩塌分别易发于斜坡坡度15°~45°和35°~90°；④泥石流灾害多发生于流域面积小于5 km2，相对高差大于100 m的沟谷中，纵坡大于212.56‰的"V"形谷中尤为发育。

The relationship between main geological hazard and topography in the Himalayan seismic belt: A case study in the Xigaze area,Tibet

The Himalayas is a huge mountain formed by the collision between the Eurasian plate and the Indian Ocean plate.In the history, there were many earthquakes with magnitude of 7 or more, which caused a large number of secondary geological disasters, and formed complex and diverse landform.Based on the previous data, field surveys and remote sensing interpretation, combined with the geomorphological map of the Himalayas seismic belt (Xigaze section), the powerful data management and spatial analysis capabilities of GIS were used to analyze major geological hazards in the Xigaze area and make maps of geological hazards and density contour.The results show that the main geological disasters are concentratedly distributed in five areas.The main geological disasters occur in strongly denudated and undulating mountains and periglacial extremely undulating mountain landforms, followed by valley plain and moraine hills.Other geomorphic features have less developmental hazards.Landslides and collapses are prone to occur on sunny slopes below 3500 m (90°~270°), and are most sensitive on the southeast-trending slope.Landslides and collapses are prone to occur at slopes of 15°~45° and 35°~90° respectively.Debris flow disasters occur most often in valleys with basin area less than 5 km2, relative elevation difference greater than 100 m, and the longitudinal slope greater than 212.56‰.They are especially developed in V-shaped valleys.