Showing 3 results for Eftekhari
Sayyd Morovat Eftekhari,
Volume 24, Issue 74 (9-2024)
Abstract
One of the consequences of the earthquake can be changes in the elevation levels of the unevenness in the area of occurrence. These changes at the level of the region will not be the same and the amount will be different under the influence of several factors such as: earthquake intensity, landforms, geo-material, and structure geological... The purpose of this research is to measure the geomorphometric changes caused by the earthquake of 17th February 2021 at the level of Dana County using the radar technique differential SAR Interferometry. To achieve this goal, taking into account the appropriate coverage and measurement accuracy of the Sentinel 1 radar satellite images from two image scenes related to the earthquake area for the dates before (2021.02.08) and after the earthquake (2021.02.20) from the organization's website. European Space Agency (ESA) was received, after performing the process and data analysis Differential Synthetic Aperture Radar Interferometry (D-InSAR), it was found that after the earthquake dated 2021,02,17, a part of the studied area was affected by positive elevation changes with a rise of 0.11 cm and Negative changes of -0.6 cm subsidence have been encountered. These positive changes (uplift) are more noticeable near the epicenter of the earthquake in the east of Dena, and the negative changes (subsidence) are quite evident with the Syncline Valley on which Khorasan Rivers is located. And in dealing with the faults, changing the geological structure, geo-material of the region, it has a special irregularity.
Mrs Negar Mirzaii, Dr Ali Ahmadabadi, Dr Seyed Morovat Eftekhari, Mrs Elaheh Lofti,
Volume 24, Issue 75 (12-2024)
Abstract
Rivers are always vital arteries of the earth and naturally, they have a gradual and continuous development process which has undergone fundamental changes after the expansion of human settlements and urban development and they have lost some of their natural functions. Wardvard River is no exception to this. This river flows in the west of Tehran province and has been heavily affected by urban development which has undergone continuous changes in its flow path due to human interference and considering that this river flows in the access route of western cities of Tehran province, its natural and gradual evolution has been disrupted that this transformation, it has removed the river from its natural condition. In this research, the factors affecting the geomorphological quality of Wardvard River have been identified and using MQI index, it had evaluated the quality of river morphology. In this method, Wardvard River is divided into 9 study periods and the three main components of the quality of geomorphological performance, artificial structures and channel adjustment have been evaluated in the form of 28 indicators. Results show due to the urban development of Tehran and many artificial changes in the Wardvard river channel, intervals 1, 3, 4, 6, 7 have earned a score of 0.2 due to human interference and canalization of the river and it is very poorly placed on the floor.Intervals 2 and 5 have earned 0.3 points and it is placed in the weak class and intervals 8 and 9 have scored 0.6 due to the low human interference and the natural course of the river and it is placed in the middle class in terms of morphological quality.
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.
