Multi-Scale Ground Deformation in Beijing Plain Revealed by a Joint 2D-FFT and MGWR Decomposition of InSAR Observation

Understanding urban surface deformation from InSAR one dimensional line-of-sight (LOS) observation is challenging due to the interplay of various natural and anthropogenic driving factors. This study proposes a novel multi-scale InSAR deformation decomposition method that integrates two-dimensional fast Fourier transform (2D-FFT) with a multi-scale geographically weighted regression model (MGWR). We apply this method to analyze urban ground deformation in the Beijing Plain, China, using Sentinel-1 data from 2016 to 2023. The results identify five significant subsidence areas with the maximum subsidence reaching -360 mm. The decomposed large-scale component (4–8 km) correlates closely with the thickness of Quaternary sediments and variations of groundwater. The medium-scale component (1–3 km) is associated with the urban construction activities, while the small-scale deformation (<0.6 km) reveals localized subsidence along subway with tunnel construction. These findings demonstrate the effectiveness of the proposed method in capturing the multi-scale deformation patterns, especially the concealed small-scale deformation, through a single orbit of InSAR observation. Therefore, it shows high potentials to improve the urban infrastructure safety such as subway engineering.