Measurement of the three-dimensional surface deformation of the Jiaju landslide using a surface-parallel flow model.

SAR Interferometry (InSAR) is a powerful technique for mapping land surface deformation, but single one-dimensional (1D) InSAR line-of-sight (LOS) measurement limits its application in three-dimensional (3D) displacement retrieval. Traditional methods were developed for measuring large-scale deformation. In this paper, to retrieve the slow 3D deformation process in the Jiaju landslide, a surface-parallel flow model is applied, according to the existing geological data gained from this landslide. Nine ENVISAT ASAR images and 19 ALOS PALSAR images were collected to reconstruct the 3D deformation field. An iterative method for correcting the characteristic value (IMCCV) with maximum likelihood estimation (M-estimation) adaptively generates an accurate stochastic model. The 3D deformation measurements show that the northern part of the Jiaju landslide clearly had horizontal deformation with the largest deformation velocity exceeding 15 cm year⁻¹, while the southern part was relatively stable. Similarly, large vertical deformation appeared in the northern part (−2 cm year⁻¹) and little deformation occurred in the southern part (−0.5 cm year⁻¹). Compared with GPS measurements, the standard deviation is 1.4 cm year⁻¹ and 0.7 cm year⁻¹ in horizontal and vertical directions, respectively. Therefore, the Jiaju landslide exhibited movements in the horizontal direction accompanied by slight settlement in the vertical direction. [ABSTRACT FROM AUTHOR]