| چکیده انگلیسی مقاله |
In recent decades, land subsidence has emerged as a geomorphological hazard and one of the environmental crises, causing irreparable damage to Iran's plains annually, with the most significant current cause being the water crisis. The Eshtehard plain, as one of the industrial and agricultural hubs of Alborz Province, is of great importance and has been declared a critical prohibited zone by the Ministry of Energy due to the sharp decline in groundwater levels. Therefore, assessing the rate of subsidence and addressing the causes and influencing factors for its risk management is of great importance.
In this study, the Differential Radar Interferometry (D-InSAR) technique was used to examine the subsidence of the Eshtehard plain, utilizing data from the Sentinel-1A satellite over the time period of 2017–2023. During this period, the region's subsidence ranged between -2.08 cm and -2.93 cm, with the highest subsidence occurring between 2019 and 2020, approximately -2.93 cm, and the lowest between 2022 and 2023, about -2.08 cm. The rate of subsidence increases from east to west and in the southern expanse. In fact, the maximum subsidence in all study periods is concentrated in the Eshtehard aquifer area, which contains a large portion of farms and villages, the city of Eshtehard, industrial towns (Kosar, Omid, and Eshtehard), agricultural lands, and the highest concentration of underground resources (wells). The results of hydrographs and interpolation using data from piezometric wells also show a drop in groundwater levels and an increase in depth in this area. At the same time, the results of examining the correlation between land subsidence and groundwater depth changes were significant at the 95% level, indicating that as groundwater depth increases, subsidence in the region also increases. Based on subsidence change profiles, the subsidence pattern in the study area is complex. These temporal and spatial variations indicate various influences, including human activities (such as the intensity and type of activity or excessive extraction of water from underground resources), environmental factors, geological characteristics (sediment composition, aquifer thickness, bedrock position, etc.), the rate of aquifer recharge and discharge, and so on.
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