Joint InSAR and discrete element numerical simulation method for landslide identification and monitoring: A case study of the Gongjue landslide, Jinshajiang River, China

Abstract Landslide disasters—prone to river blocking—are widely distributed in the mountainous areas of southwest China and are characterized by high-elevation long-runout movement with great destructive power. Identification and monitoring of high-elevation long-runout landslides and the prediction of unstable landslide movements are of great significance for regional disaster mitigation and prevention. In this study, we used interferometric synthetic aperture radar (InSAR) to identify and monitor potential landslides in Gongjue County, China and selected the Sela landslide as a model to analyze current and unstable landslide movements. The monitoring results show that Gongjue County, in the area of the Jinsha River, contains four typical landslides with slope deformation rates exceeding − 17 cm/yr. The maximum slope deformation rate reaches − 46 cm/yr. The decomposition results of the time-series deformation characteristics of the landslide feature points show that the landslide periodic term deformation has a certain correlation with rainfall. Based on the discrete element model MatDEM and InSAR monitoring results, the simulation of the movement of the Sela landslide under natural gravity and sliding instability shows that the Sela landslide is still in a stable stage under natural gravity conditions, whereas under conditions of instability, most of the landslide bodies will slide rapidly into the Jinsha River, and there is a greater risk of river blockage. The results of this study provide an important reference for carrying out remote monitoring and risk prediction for high-elevation long-runout landslides.