عنوان مقاله [English]
Heyran Ardabil road is one of the areas with potential for range movements due to various geological characteristics such as tectonics, lithology, seismicity and climatic conditions. For this purpose, radar images of the European Space Agency's Sentinel 1 satellite have been used to identify and estimate the speed and amount of movements of unstable slopes overlooking the Heyran-Ardabil communication routes over a six-year period from 2015 to 2021. In order to process the information, it has been used using interference technique and SARSCAPE software. Landsat 8 image was used to prepare the land use map of the study area using the object-oriented classification method in eCognition Developer64 software. Was extracted. The results obtained in this study showed that radar satellite images and interferometry techniques are very suitable for detecting slope instability and calculating the amount of displacements due to their extensive coverage, high accuracy and abundance of data. The maximum amount of material movement is in the range of 30 cm in the study area. Which indicates that the area is active in terms of amplitude movements. Land use maps using Landsat 8 image were used using object-oriented classification in the study area. Co-institutionalization of landslide maps with land use layers also confirms the maximum occurrence of landslide area related to forest areas and residential area shows the highest amount of landslide. The reason for this is the climatic conditions and the potential for rainfall in all seasons of the year, the infiltration and direction of rainwater to the lower classes.
Continuous monitoring of land surface changes and identification of areas prone to slip movements, especially in the area of human settlements and communication infrastructure such as roads and railways, is one of the most effective factors in reducing casualties and natural hazards such as landslides and slopes. So far, several techniques have been proposed such as using the Global Positioning System, geodesy and tachometry, mapping cameras, laser scanning and lidar to monitor surface changes. However, due to the high cost of implementation, time consuming and limited coverage of the use of these methods, in the limited, the use of these methods in a wide range is not cost effective. But in addition to these methods, the radar interference technique with the ability to work in all weather conditions and the duration of day and night and with the ability to cover the ground and high spatial and temporal resolution, today is one of the most accurate (in millimeters) and least expensive Remote sensing techniques for detecting and monitoring surface changes, slow and unstable movements of amplitude around the world.
Heyran Pass is located on the Ardabil-Stara communication route. This pass is located in the northeast of Ardabil and west of the border city of Astara. Tectonically, the region has obvious faults such as Astara fault. Different formations can be identified in the route of Heyran pass from Namin to Astara. From near Namin to the village of Hiran, the main rock is the Eocene pyroxene andesitic volcanic section. In a part of this route, conglomerate sediments with loose cement with volcanic fragments have been placed on andesitic volcanic sections as igneous discontinuities. From Hiran village to 15 km from Astara, tuff sandstones with a layer of Paleocene andesitic lava and Quaternary sediments are located, respectively.
Optical satellite imagery, including Landsat satellite imagery for 2021. In the image processing phase, the 2015 and 2021 Sentinel 1 time series were used in the C-bar. Using image processing with SARSCAPE 5.2 plugin in ENVI 5.3 software platform and using radar interferometry method, landslide affected areas in each area were determined. In the next step, using the survey operation, landslide effects in the area were identified. In order to explain the causes of landslides in the study area, land use data as well as information about observation wells were compared and statistically analyzed with results in the area.
The results in accordance with the land use map and the landslide map showed that the highest landslides are in the residential area with 30 cm and the forest with 30 cm. The amount of lift in all three uses indicates the amount of 2 to 30 cm of landslide. Sudden landslides and the destruction of vulnerable structures are possible landslide accidents that cause casualties in urban areas. In some cases, these accidents can cause severe and irreparable damage due to high population density or widening of the radius of collapsed lands. However, by institutionalizing the forms, it can be concluded that the highest rate of landslides in residential and densely populated areas as well as forests has the highest rate of landslides.
Discussion & Conclusions
The results of this study showed that radar images have a good potential for detecting slope instability and calculating their displacement. The maximum amount of material movement is 30 cm in the study area. Which indicates that the area is active in terms of amplitude movements. Land use maps using Landsat 8 image were used using object-oriented classification in the study area. The results of matching the land use map and landslide map in Table 3 showed that the highest landslide rates The highest landslide rates are in residential area uses with a value of 30, forest with a value of 30 and rangeland with a value of 24 cm, respectively. . It shows the minimum value for agricultural use with 21 cm and barren with 20 cm. The sudden collapse of the earth and the destruction and collapse of vulnerable structures are possible accidents caused by landslides that face human casualties in urban areas. In some cases, these accidents can cause heavy and irreparable losses due to high population density or the expansion of the radius of the collapsed lands. However, by institutionalizing the shapes, it can be concluded that the highest landslide rate occurred in residential and densely populated areas, and also in forest use, it has the highest landslide rate.
Key Words: Landslide , Radar Interference, Sentinel 1 Images, Object Oriented Classification,