Characteristics of landslide in Koshi River Basin, Central Himalaya

摘要: Koshi River basin, which lies in the Central Himalayas with an area of 71,500 km(2), is important trans-boundary river basin shared by China, Nepal and India. Yet, landslide-prone areas are all located China Nepal, imposing alarming risks widespread damages to property loss human life both countries. Against this backdrop, research, utilizing remote sensing images topographic maps, has identified a total number 6877 landslides for past 23 years further examined their distribution, characteristics causes. Analysis shows that two-step topography Himalayan region considerable effect on distribution area. Dense falls into two regions: Lesser Himalaya (mostly small medium size east-west direction) Transition Belt large along north-south direction). Landslides decrease against elevation while southern slopes have more than its northern side. Change analysis was carried out comparing landslide data 1992, 2010 2015 basin. The rainfall-induced landslides, usually shallow occurring frequently regions lower 1000m, common south south-east due heavy precipitation region, prone slope gradient 20 degrees similar 30 degrees. Most them distributed Proterozoic stratum (Pt-3 epsilon, Pt-3 Pt2-3) Quaternary stratum. While earthquake-induced they higher elevations (2000 3000 m) steeper (40 50 degrees).