Risk Vulnerability Analysis of Residential Areas Against Land Subsidence in the Lenjan Region Using a GIS Based Approach

Land subsidence has emerged as one of the most critical environmental and urban hazards in arid and semi-arid regions of Iran, particularly within the Lanjan Plain in Isfahan Province. This study aimed to analyze the vulnerability of residential areas to land subsidence and develop a comprehensive risk map using a GIS-based multi-criteria decision-making (MCDM) approach. The methodology integrated key physical, hydrogeological, and socio-economic indicators, including groundwater drawdown, soil compressibility, land use type, slope, and proximity to groundwater extraction wells. The Analytic Hierarchy Process (AHP) was applied to assign relative weights to each criterion, revealing that groundwater decline (۰.۳۲) and soil compressibility (۰.۲۷) were the most influential factors in subsidence hazard. Vulnerability analysis incorporated population density, building quality, and accessibility to emergency services, with population density identified as the dominant vulnerability driver. By integrating hazard and vulnerability layers through a GIS-based weighted overlay, the study produced a spatial risk model that categorized residential zones into five risk levels, ranging from very low to very high. Results indicated that approximately ۲۸% of the Lanjan Plain's residential areas fall within high or very high-risk zones, primarily concentrated near intensive agricultural and industrial pumping sites. The findings are consistent with recent studies on land subsidence in central Iran and underscore the urgent need for groundwater extraction management, urban planning reforms, and continuous monitoring through remote sensing and geotechnical observations.

کلیدواژه ها:

Land Subsidence ، GIS ، Risk Mapping ، Lanjan Plain