Enhanced Kinematic Inversion of 3‐D Displacements, Geometry, and Hydraulic Properties of a North‐South Slow‐Moving Landslide in Three Gorges Reservoir

Abstract Complete three‐dimensional (3‐D) movements of slow‐moving landslides are critical to enhancing the understanding of the landslide mechanism. Multi‐source synthetic aperture radar (SAR) observations provide an opportunity to derive 3‐D movements. However, deriving the complete 3‐D movements faces potential challenges of incoherent phases and an ill‐posed inverse problem, which may result in incomplete and inaccurate results, especially for slopes facing north/south. Here, we propose a topography‐constrained strain model, which exploits the spatial relationship of 3‐D deformations between neighboring points as well as the assumption of the surface parallel flow of landslide, to derive complete 3‐D movements. Both synthetic and real datasets over the north‐south Xinpu landslide complex are utilized, to assess if the implemented method can overcome the ill‐posed condition and retrieve the complete 3‐D movement field. With the multi‐source SAR datasets, the performance of various datasets and the potential of NISAR in deriving time series and 3‐D movements are assessed. Based on the derived complete 3‐D movements and long‐term InSAR measurements, the landslide metrics, including elementary parameters of landslide geometry, spatial‐temporal patterns of movement, thickness, and hydraulic diffusivity, are derived to reveal that (a) the thickest landslide mass concentrates in the toe of the landslide, and (b) the effects of precipitation are more significant than those of the water level fluctuation in the Xinpu landslide complex, Three Gorges Reservoir areas.