Analysis of Slope Dynamics and Determination of Active Landslides in Qazvin Alamut River Basin with Radar Data

Slope hazards and landslides annually inflict substantial damage in the mountainous regions of Iran, particularly within the eastern Alamut area of Qazvin province.Recent advancements in radar technology have facilitated the detection of ground surface movements, including slow slope motions and active landslides.The present study employs Sentinel 1A satellite descending data from 2018 to 2020, utilizing the Small Baseline Subset (SBaS-InSAR) methodology alongside digital elevation model (DEM) difference techniques.This approach aims to extract slope movements and Earth surface displacements, serving the critical objective of identifying new and active landslides while updating the landslide map to enhance landslide risk prediction.The results indicate that the SBaS model, which was corroborated with GPS data, field investigations, and Google Earth imagery, demonstrated a commendable level of accuracy (AUC = 0.78).The average annual movement over the study period was estimated to range from -48.6 to 40.2 mm, leading to the identification of fourteen landslide zones in the region, several of which continue to exhibit activity.Specifically, the landslide that transpired in Khobkuh on April 3, 2020, was assessed using the DEM difference model, which estimated surface changes between -1.62 and 2.75 meters.Conversely, the differential interferometry model calculated the displacement rate in this area to be between -25 and 70 mm.These methodologies offer significant advantages for estimating Earth surface displacement, subsidence, and landslides, facilitating the identification of vulnerable areas in mountainous regions and contributing to the mitigation of financial and human losses.