High-temporal-resolution slope-aspect deformation extraction and evolution analysis of the Xiongba landslide group...

The Xiongba landslide group, characterized by continuous movement and distinct signs of reactivation, necessitates continuous monitoring to mitigate potential hazards. While Interferometric Synthetic Aperture Radar (InSAR) offers wide-area coverage and high precision, its limitation to line-of-sight (LOS) measurements and constrained temporal resolution hinders the accurate characterization of true kinematic directions and dynamic evolutionary patterns. To address these constraints, this study proposes a method that first projects LOS deformations onto the slope-aspect direction to reveal actual displacement vectors. Subsequently, an Unscented Kalman Filter (UKF) is employed to fuse ascending and descending Sentinel-1A time-series slope-aspect deformations, thereby enhancing temporal resolution and capturing the landslide's dynamic evolution. Monitoring results based on Sentinel-1A data from January 2018 to June 2024 indicate that the Xiongba, Sela, Maiba, and Gongba landslides remain in a state of continuous activity. Notably, the Xiongba landslide exhibits maximum LOS deformation rates of 94.78 mm/yr (ascending) and 82.57 mm/yr (descending). Quantitative validation demonstrates that the UKF method significantly improves monitoring accuracy, reducing the Root Mean Square Error (RMSE) by 32.1% compared to the traditional Kalman filter, while shortening the average observation interval to 7.18 days. The evolutionary analysis reveals that the deformation is primarily driven by gravitational forces and river erosion traction, and triggered by seasonal rainfall events.