Journal of Sustainable Urban & Regional Development Studies (JSURDS)

Abstract Background and Objective: Landslides are among the most common natural hazards, causing extensive economic, environmental, and human losses. This study aims to assess and map landslide susceptibility in the Siah Rud watershed located in Gilan Province, using a hybrid approach that integrates the Analytic Network Process (ANP) model with Geographic Information Systems (GIS).
Methodology: This applied, descriptive-analytical research utilizes the ANP model within the GIS environment to delineate landslide hazard zones in the Siah Rud watershed. Ten influential factors were selected for the analysis: land use, elevation, slope, slope aspect, vegetation cover, precipitation, geological formations, and distances from roads, rivers, and faults. The relevant thematic layers were derived using various data sources, including DEMs, Landsat 8 and Sentinel-2 satellite imagery, geological maps, and precipitation maps. Analytical tools in ArcGIS were employed to extract certain layers, such as distance from rivers and roads. The ANP model, which surpasses AHP in modeling interdependencies between criteria, was used for weighting and final analysis.
Results and Findings: According to the ANP weighting results, the variables with the highest influence on landslide occurrence were slope (0.27), geological formations (0.24), and precipitation (0.16). Spatial analysis further revealed that areas with steep slopes, weak volcanic and sedimentary formations, high rainfall, and proximity to faults and rivers had greater instability potential. In contrast, regions with dense vegetation, forest land use, and significant distances from roads and faults showed higher stability. The final GIS-based hazard zonation map classified the area into five risk levels, with 36% of the watershed falling into high and very high hazard zones. These high-risk areas were primarily concentrated in the upstream parts of the watershed, where the combination of steep topography, high rainfall, sparse vegetation, and unstable geological conditions contributes to widespread landslide susceptibility.

Abstract Landslide is always a serious threat to human settlements. In the Face of such accidents, little can be done at the moment of occurrence. Before that, its effects can be foiled with planning and for reduction of possible casualties and damages. The aim of the present study is to take a systematic look at natural hazards, including Landslide in order to draw up a scientific and accurate plan outlining for preparation and planning based on the use of spatial information systems and multi-criteria decision-making models in line with the zoning risk landslides and determining the direction of residential development is predictable. The present study extracted 15 effective criteria in landslide risk. Then using of the results of the evaluation of two models of (DEMATEL, FUZZY hierarchical analysis process) showed that the DEMATEL model is in accordance with the principles and laws of mathematical and has more certainty. While the process of FUZZY hierarchical analysis was only consistent with the knowledge and expertise rating. In the risk zone whit the DEMATEL model low risk, zones %37/1 (190/39 km²) it has the largest area of 513/12 square kilometers, have most area of surface. Also, high risk zone with %2/32 (11/89 km²), high and medium risk zones each with %34/33(176/13 km²) and low risk by 134/71(%26/25 km²) were next in the ranking. Zoning and risk with FUZZY hierarchical analysis, risk zone of very small allotment, %36/53(187/43 km²) and low risk zone of %17/73(90/96 km²) and medium risk zone %17/79(91/27 km²), and high risk zone of %16/84(86/41 km²), as well as very high risk zone%11/2(57/6 km²) were ranked.