Landslide hazard zoning using GIS-based methods and radar data (Case study: Fereydoon Shahr)

Using different methods in landslide risk zoning and achieving the best results can lead to planning and managing potential hazards. The main objective of this study is to assess and determine the potential risk of landslide in Fereydoon Shahr city, west of Isfahan province, to provide a general framework for analyzing the probable landslide hazard in the study area. In this study, the accuracy of statistical and expert analysis (GIS-based) methods was analyzed using the Sentinel-1 radar interferometry method. This analysis leads to the presentation of the landslide hazard zoning map, susceptible areas, and determination of the factors affecting the landslide occurrence. Initially, for risk assessment and zonation, the causative factors including slope, elevation, gradient direction, curvature, distance to fault, distance to waterway, lithology, and vegetation were studied. And statistical correlation was created between each of the causative factors and past landslides in the GIS environment to assess the relative share of classes related to each factor. In the expert analysis method, the study area was analyzed based on expert opinion based on studies conducted on 70 landslides. The results, in addition to the Fereydoon Shahr sensitive and hazardous area map, showed about 67% overlap of very-high and high-risk areas in the risk zoning maps with pixels from the surface displacement map obtained from Sentinel radar images with the highest displacement. Which can indicate the possibility of landslides or landslide risk in these areas. Therefore, the use of radar images and the study of changes in land displacement can be a useful tool in monitoring and accuracy of the landslide risk zoning methods for planning in sensitive areas.