Roghayeh Delaram, Samad Fotohi, Mohsen Hamidianpoor, Morteza Salari,
Volume 24, Issue 72 (3-2024)
Abstract
The subsidence phenomenon is considered one of the most frequent hazards occurring worldwide and imposing irreparable damages every year. This phenomenon affects the ground’s surface and its layers and causes the ground deformation. It can be referred to as a morphological phenomenon that is associated with the gradual sinking of the ground and the vertical movement of materials. Among the various methods used to study the land subsidence pattern, the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique has provided more accurate results. Therefore, this technique was used to investigate the subsidence rate in Mashhad plain from 2003 to 2010 and the Envisat ASAR (C-band) and Sentinel-1 ASAR (C-band) satellite images were employed during the year 2019. The results show that the highest subsidence rate of about 44 cm occurred in Qasem Abad and Kalateh-ye Barfi lands from 2008 to 2010. A subsidence rate of about 37 cm was also observed in the same area from 2007 to 2009. The interpolation results using piezometer well statistics show a decrease in groundwater levels in this area and confirm the accuracy of the results.
Mohammadreza Goodarzi, Maryam Sabaghzadeh, Amirreza Rajabpour Niknam,
Volume 25, Issue 76 (3-2025)
Abstract
In arid and semi-arid regions, groundwater is more important for humans and ecosystems than surface water. Land subsidence is caused by the pumping and uncontrolled use of groundwater in an area. When the extracted quantities are not replenished by rainfall, it leads to damages such as road failures, destruction of residential areas, railways, as well as water and gas pipelines. The Yazd-Ardakan plain is one of the main plains in Yazd province, hosting 75% of the province's population density and most industrial centers. Additionally, this plain has been subjected to a ban by the Ministry of Energy due to a sharp decline in groundwater levels. This study aimed to quantify and compare the extent of subsidence using four Synthetic Aperture Radar (SAR) images of the C-band from the Sentinel-1 satellite and the radar differential interferometry method from 2017 to 2021. The maximum subsidence recorded in 2017 was 13 cm, while in 2020 and 2021, it decreased to 9 cm, primarily concentrated in the Shamsi region between Meybod and Ardakan. Furthermore, to validate the satellite-derived results, they were compared with those obtained through accurate leveling methods conducted by the Iran National Cartographic Center. The study revealed that Sentinel images exhibit a strong capability to estimate the extent of subsidence. Considering the examination of groundwater consumption and depletion statistics in recent years, potential reasons for the reduction in subsidence in the study area could be attributed to management measures such as water transfer to this basin, alterations in agricultural practices, and a decrease in groundwater depletion compared to previous years in this region.
Miss Rana Norouzi, Mr Sayyd Morovat Eftekhari, Mr Ali Ahmadabadi, Miss Khadijeh Alinoori,
Volume 25, Issue 78 (9-2025)
Abstract
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.
