Somayeh Taheri; Hasan Ahmadi; Jamal Ghodousi; ُSadat Feiznia; Shahram Khalighi Sigaroudi; Mohamad Hossein Ramesht
Abstract
subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight ...
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subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight of Evidence (WoE) model. To achieve this, we created maps of factors influencing subsidence, such as slope, alluvial thickness, groundwater fluctuations, aquifer layering, particle size, and permeability. These maps were then compared with recorded subsidence data to determine the weight of each factor's influence. By integrating the effects of these factors, a Subsidence Index (SI) map was generated and categorized using the Success Rate Curve (SRC), identifying five sensitivity zones from very sensitive to very low sensitivity. The effectiveness of the WoE model was evaluated, revealing that the subsidence sensitivity prediction map covers 93.64% of actual occurrences. Results indicated that aquifer layering positively influences subsidence development, with the highest impact arising from alluvial deposits with good permeability and fine particles. This factor, with a weight of 3.72, demonstrates significant influence among all evaluated parameters. In terms of thickness, the most significant subsidence occurred in alluvial deposits exceeding 200 meters. Areas experiencing groundwater level declines of over half a meter annually markedly contributed to subsidence. Additionally, slopes of less than two degrees were identified as the most susceptible to subsidence. Thus, while many areas in Karaj are relatively safe, the threat is notably higher in the southern and southwestern parts, requiring special attention in urban management.
