Slope Movement Monitoring in Colluvium Deposit Landslide at Doi Chang, Thailand by Sentinel-1 Differential InSAR

Differential interferometric synthetic aperture radar (D-InSAR) techniques are a well-established remote sensing tool used for natural hazard detection and monitoring. The Sentinel-1 satellite mission provides extensive spatial coverage, regular temporal sampling, and accessible data availability, making it an ideal source for D-InSAR analysis. In this study, D-InSAR analysis was performed over the potential slope deformation area in the colluvium deposit at Doi Chang, Chiang Rai province, Thailand, using all Sentinel-1 images acquired between March 2016 and March 2017. The results show that the slope movement in colluvium deposits at Doi Chang was slow during the dry season, but its velocity significantly increased during the rainy season, confirming the slope movement behavior observed during site investigation data. The movement rate was sufficient to cause recurrent damage to infrastructure, such as roads and buildings, resulting in economic loss and public concerns. The D-InSAR results revealed substantial activity and displacement behavior on the spatial–temporal evolution. Furthermore, observations were validated, and their accuracy was confirmed via comparison to ground truth data from borehole inclinometers. The detected displacement time series provides an understanding of the spatial–temporal evolution of the corresponding deformation phenomena.