Instability mechanism and disaster mitigation measures of long-distance landslide at high location in Jinsha River junction zone: case study of Sela landslide in Jinsha River, Tibet

The Jinsha River junction zone is the active fault one dominated by strong compression. It belongs to the topography of high mountains and valleys, the rockmass structure is complex, and the weak rock strata develop, and the high-location geo-hazards occur frequently. Taking Sela landslide in the Jinsha River as an example, the methods of multi-phase remote sensing data, field investigation and surveying, multi-phase InSAR dynamic observation, geophysical exploration and surface displacement monitoring are used to analyze the basic characteristics, deformation process, development trend and formation mechanism of Sela landslide. Considering the hydropower development and special geological conditions of the Jinsha River, the early identification and disaster risk management of high-position landslides are discussed. The results are as follows: Sela landslide is a typical one with the height difference of 693 m and the volume of about 6520×10⁴ m³. Based on its deformation characteristics, the landslide is divided into three deformation areas. Under the influences of geological structure, stratigraphic lithology, rainfall and river erosion, the instability mode of the landslide is a multistage progressive failure, which is likely to occur in the front of the landslide in the future. The advanced technology such as the integration of space and earth can identify the deformation area and deformation quantity of the high-position landslide in time, and provide scientific basis for the disaster prevention and mitigation of basin disaster chain.