Geomorphology
farhad khodamoradi; Shahram Roostaei; Ali Zareiyan
Abstract
Landslides are influenced by internal, external (climatic), and anthropogenic factors. Salavatabad Pass, located in eastern Sanandaj along the Sanandaj–Hamedan route, is a highly vulnerable area experiencing recurrent landslides. The presence of the main road, along with uncontrolled construction, ...
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Landslides are influenced by internal, external (climatic), and anthropogenic factors. Salavatabad Pass, located in eastern Sanandaj along the Sanandaj–Hamedan route, is a highly vulnerable area experiencing recurrent landslides. The presence of the main road, along with uncontrolled construction, gardening, and road construction, has exacerbated these hazards. This study aims to identify, quantify, and classify continuous slope movements using radar interferometry and land use analysis. To assess vegetation cover, the NDVI index was derived from eight Sentinel-2 images, aiding in the selection of appropriate radar imagery. Additionally, four Sentinel-1 images from 2020 to 2023 were processed in SNAP software to analyze surface displacements. The land use map was generated using a 2023 Landsat-8 image, with supervised classification applied in ArcGIS, categorizing the area into six classes. The results indicate an annual displacement of 2.4 cm, totaling 9.5 cm over the study period. Hazard zoning revealed that 14.45% of the area falls within the high-risk category, while 29.33% is classified as moderate risk. The road network was divided into three segments, with the first (6.59 km) and second (6.6 km) segments classified as high and moderate risk, respectively. Ultimately, 18 unstable zones were identified along the road, with 16 primarily associated with rangeland and barren land use. The highest displacements were observed on slopes with northern, northwestern, southern, and western aspects..
Geomorphology
sayyad Asghari Saraskanroud; Fariba Esfandyari; Mehdi Faal Naziri; Batool Zeinali
Abstract
Land subsidence refers to the gradual or sudden lowering of the earth's surface as a result of various factors such as tectonic activities, mining, oil and gas fields, and illegal extraction of underground water. In Alborz province, the growing trend of population and migration in recent years has added ...
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Land subsidence refers to the gradual or sudden lowering of the earth's surface as a result of various factors such as tectonic activities, mining, oil and gas fields, and illegal extraction of underground water. In Alborz province, the growing trend of population and migration in recent years has added to the increase in demand and the amount of water withdrawal from the underground water table, so it is subject to subsidence due to the sharp drop in the level of underground water. In this research, subsidence was first evaluated using the radar interferometric technique, and then, prone areas were zoned with a multi-criteria algorithm in the time frame of 2016 and 2023. The results of information extraction with interferometric technique showed that the average amount of subsidence in the urban boundaries of Saujblag, Karaj, Nazarabad, Chaharbagh and Fardis is between 15 and 320 mm. According to observations, the highest amount of subsidence is in the eastern part and then in the southern and southwestern parts. According to the estimated results of subsidence risk zoning; The parameters of water level drop, land use, slope and geology, respectively, with weight coefficients of 0.16127, 0.141875, 0.130145 and 0.128474, are the most important factors in creating the risk of subsidence in the study area, which are 31 and 23%, respectively. From the range, it has a very high and high probability of danger. Finally, it can be said that the most important factor in subsidence in the studied area is excessive use of underground water and the drop in water level. In some urban areas, such as Hew and Goch Hesar, Malekabad-Mehrshahr-Mehrvila-Kamalshahr, and Mohammadshahr, the highest risk of subsidence can be seen.
Groundwater
Mohammad Hossain Motedayen; Mehrdad Esfandiari; Abolfazl Moeini; Ali Mohammadi Torkashvand
Abstract
In recent years, the irreversible phenomenon of land subsidence has led to environmental hazards in various plains of Iran including Gorgan. In general, the most important activities causing this phenomenon are inappropriate groundwater withdrawal and geological factors. The research method consists ...
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In recent years, the irreversible phenomenon of land subsidence has led to environmental hazards in various plains of Iran including Gorgan. In general, the most important activities causing this phenomenon are inappropriate groundwater withdrawal and geological factors. The research method consists of two sections: identifying subsidence areas and examining the effective factors and parameters and evaluating the impact of each. In identification section, radar interferometry technique was used to compare the phase taken from two radar sets from the same region at two different times and measurement of land surface changes over time can be achieved through interferogram, and in the effective factors analyzing section, the determination and analysis of effective parameters such as water level drop, texture and thickness of soil layers, especially fine-grained layers were investigated. The results of the satellite data analysis indicate that the region is steadily subsiding. The mean velocity map along the satellite line of sight obtained from time series analysis showed a subsidence rate of 14 mm / month (169 mm / year). The identified subsidence range is approximately eastern-western which is consistent with trends in structures such as the Caspian. Figures of water level and precipitation in this area during 2007 to 2009 show a decreasing trend despite of seasonal fluctuations, and analysis of effective parameters shows that the subsidence is due to the same drop in water level or the difference of same thickness of the fine-grained layer at different depths
