Landslides detection and risk analysis of typical landslide along the Mekong river (Chamdo section) in the eastern Tibetan Plateau.

Abstract

Abstract: The Mekong River is one of the major international rivers in the Hengduan mountainous region of the eastern Tibetan Plateau. Because of the canyon geomorphology, weak lithology, and strong human engineering activities, a large number of landslides have developed along the Mekong River (Chamdo section). The area also contains human settlements such as the urban area of Chamdo city and the county town of Chaya, as well as human engineering facilities such as G214 and the Sichuan-Tibet Railway under construction, so the detection and risk analysis of landslides are of great practical significance. Based on the field investigation, combined with optical images and InSAR deformation interpretation, 75 landslides along the main stream of the Mekong River were detected, and the spatial distribution characteristics and main influencing factors of these landslides were further summarized. Chaya landslide complex is one of the typical landslides in the Mekong River, and Chaya County is its direct threat. Through the optical remote sensing images and InSAR deformation interpretation, combined with the UAV field investigation, it was found that SBAS-InSAR revealed that the areas of landslide clusters with deformation rates greater than 20 mm/y have been undergoing different degrees of collapse and slippage in recent years, and the secondary destabilization of the accumulation body in the areas with deformation rates up to 68 mm/y has almost caused the danger of blocking the river; The comparative analysis of rainfall and deformation rate during the period of 2018~2020 concluded that the deformation increment of the landslide cluster is strongly correlated with rainfall, but with a certain degree of hysteresis. Rainfall, river erosion and human engineering activities are the drivers of sustained deformation damage. Finally, the numerical simulation analysis of the disaster risk of the potential landslide areas was carried out by Massflow software, and the results showed that once the destabilized landslide occurs in some areas, there will be the risk of destroying the houses and blocking the river.