A Large Old Landslide in Sichuan Province, China: Surface Displacement Monitoring and Potential Instability Assessment

Using advanced Differential Interferometric Synthetic Aperture Radar (InSAR) with small baseline subsets (SBAS) and Permanent Scatter Interferometry (PSI) techniques C-band Sentinel-1A data, this research monitored the surface displacement of a large old landslide at Xuecheng town, Lixian County, Sichuan Province, China. Based on MassMov2D model, effect dynamic process deposit thickness potentially unstable rock mass (deformation rate < ?70 mm/year) body were numerically simulated. Combined terrain data images generated by an Unmanned Aerial Vehicle (UAV), driving factors analyzed. The InSAR results show that motion in middle part is largest, range ?55 to ?80 mm/year average, whereas those upper toe area small, ?5 ?20 mm/year. Our suggests there correlation between LOS (line sight) deformation rainfall. In rainy seasons, particularly from May July, relatively high. addition, analysis SBAS can provide smoother time series, even areas vegetation steepest sectors landslide. simulation may collapse form barrier dam maximum about 16 m Zagunao river future. This study demonstrates combining temporal UAV measurements SAR allows early recognition monitoring reactivation complex mountainous areas. information provided increase understanding landslides area, which would enhance urban safety assist disaster mitigation.