Early Detection of Landslides in the Upstream and Downstream Areas of the Baige Landslide, the Jinsha River Based on Optical Remote Sensing and InSAR Technologies

On October 11 and November 3, 2018, two large-scale landslides occurred in the upstream of the Jinsha River near the Baige Village, Polo Town, Jiangda County, Tibet Autonomous Region. Although the drainage was carried out by manual intervention, it still caused severe losses to the residents and transportation facilities in the downstream. Whether there are similar large-scale potential landslides in the upstream and downstream of the Jinsha River has become the social focus issue after the Baige Landslide disaster occurred. Firstly, high-resolution optical satellite images are used to interpret and qualitatively evaluate the potential landslide hazards in the upstream of the Baige Landslide within 30 km and the downstream of the Baige Landslide within 100 km. A total of 51 potential landslides are identified, of which 10 potential landslides in the downstream of the Baige Landslide within 70-100 km have the risk of blocking the river. On this basis, the ALOS PALSAR-1 and Sentinel-1A radar satellite data are collected in the key area (70-100 km downstream of the Baige Landslide) with the risk of river blockage. The quantitative detection and analysis of the potential surface deformation of landslides are carried out by using the small baseline subsets interferometric synthetic aperture radar (SBAS-InSAR). Seven potential landslides are detected to have significant deformation, of which three are at higher risk of river blockage. The research results have been submitted to the Ministry of Emergency Management, Sichuan Natural Resources Department, China Railway Second Academy Engineering Group Co. Ltd. and other departments and units, providing a reference for the prevention and control of geological hazards in the upstream and downstream of the Baige Landslide and the route selection of Sichuan-Tibet railway.