Deformation monitoring of slow-moving landslide with L- and C-band SAR interferometry

SAR interferometry (InSAR) is an effective tool for wide-area earth surface deformation detection and mapping. In this letter, Persistent Scatterers InSAR method was employed to derive the deformation histories of Huangtupo and Zhaoshuling landslides located in Badong County of the Three Gorges area. One Environmental Satellite C-band Advanced Synthetic Aperture Radar (ASAR) data stack acquired from descending orbit and two Advanced Land Observation Satellite Phased Array type L-band Synthetic Aperture Radar (PALSAR) data stacks collected from two adjacent ascending orbits were used. Different deformation trends were observed from the descending and ascending data stacks. Disagreements were found on Huangtupo and Zhaoshuling landslides between measurements of ASAR data and PALSAR data, which might be primarily attributed to different viewing geometries. Meanwhile, due to smaller decorrelation effects for longer wavelength, L-band PALSAR data can be used to detect more point-like targets than C-band ASAR data, which makes it more suitable for monitoring landslides in vegetated areas such as the Three Gorges. Preliminary temporal correlation analyses between deformation measurements and water level fluctuation as well as rainfall were performed to explore the driving mechanism for landslide motion within the Three Gorges Reservoir area.