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جستجوی مقالات مرتبط با کلیدواژه "تداخل سنجی راداری" در نشریات گروه "جغرافیا"

تکرار جستجوی کلیدواژه «تداخل سنجی راداری» در نشریات گروه «علوم انسانی»
  • محمد فتح الله زاده*، مجتبی یمانی، ابوالقاسم گورابی، مهران مقصودی، مهرنوش قدیمی

    مورفوتکتونیک، دانش کاربرد اصول ژئومورفیک در حل مسائل تکتونیکی است. رقابت مداوم بین فرآیندهای تکتونیکی که تمایل به ایجاد توپوگرافی دارند و فرآیندهای سطحی که تمایل به فرسایش و متلاشی کردن آنها دارند، اساس علم مورفوتکتونیک است. جلگه های ساحلی به دلیل عملکرد همزمان فعالیت های تکتونیکی بر دو محیط خشکی_آبی، دارای لندفرم ها و چشم اندازهای نوزمین ساختی قابل تمایزی هستند. مناطق ساحلی شمال ایران به دلیل تراکم بالای جمعیت و قابلیت رشد و توسعه اقتصادی و کشاورزی، از اهمیت بسیاری برخوردار است. یکی از روش های شناسایی و اندازه گیری تغییرات زمین استفاده از دورسنجی راداری است. اصول این تکنیک برای اولین بار توسط گراهام در سال 1974 بیان شد. در این پژوهش نوار ساحل شرقی دریای خزر از گمیشان تا جویبار از نظر فعالیت های تکتونیکی با استفاده از تکنیک های دورسنجی راداری در بازه زمانی 2014 تا 2021 مورد پایش قرار گرفت. اگرچه بازه زمانی انتخابی در مقیاس زمانی زمین شناسی کوچک محسوب می شود، اما شدت عملکرد فرایندهای تکتونیک در منطقه امکان تمایز مناطق فعال ساحلی را مشخص می کند. نتایج بدست آمده از تداخل سنجی راداری بیانگر آن است که بخش شرقی ساحل خزر بیشتر تحت تاثیر بالاآمدگی بوده و این روند تا خلیج گرگان ادامه دارد بطوری که محدوده شهر گرگان نرخ بالا آمدگی 20 تا 40 میلی متر در سال را تجربه کرده است. روند تغییرشکل به سمت ناحیه ساحلی معکوس شده و فرونشستی معادل 10 تا 52 میلی متر در سال را داشته است. با نزدیک شدن به کرانه خزر این نرخ کمتر شده و به 10 میلی متر در سال می رسد. با توجه به اینکه در نوار ساحلی خزر آب های سطحی فراوان بوده و بهره برداری از آب زیرزمینی در این مناطق بسیار اندک است، از این رو  با اطمینان بالایی می توان عامل رخداد بالاآمدگی و فروافتادگی (گمیشان) در این مناطق را به سازوکار تکتونیک و فعالیت گسل های فعال منطقه نسبت داد.

    کلید واژگان: مورفوتکتونیک, ساحل, جلگه خزر, تداخل سنجی راداری, ژئودینامیک
    Mohamad Fathollahzadeh *, Mojtaba Yamani, Abolghasem Goorabi, Mehran Maghsoudi, Mernoosh Ghadimi
    Introduction

    The landforms created by tectonic processes are studied by morphotectonics, in other words, morphotectonics is the science of applying geomorphic principles in solving tectonic problems. Quantitative landscape measurements are usually based on the calculation of geomorphic indices, using topographic maps, satellite images aerial photographs, and field visits. Coastal deltas are part of landforms and landscapes that, due to the proximity of two environments, land, and water, leave visible effects against tectonic activities, such as changing the pattern and location of deltas due to the change in the course of coastal rivers, the formation of unbalanced coastal terraces in parts of the coast, and the emergence of cut beaches in the form of seawalls.One of the methods of identifying and measuring land changes is using radar remote sensing. The principles of this technique were first described by Graham in 1974 (Pacheco et al., 2006). Interferometry using radar images with an artificial window or SAR is a precise method based on the use of at least two radar images of the same area, which measures the height displacement changes in wide areas and during different time intervals with a significant accuracy of millimeters (Dong et al., 2018).The coastal areas of northern Iran are of great importance due to the high population density and the ability to grow and develop economically and agriculturally, so monitoring geomorphic changes in the direction of sustainable development of these areas is particularly important.In this research, the eastern coast of the Caspian Sea from Gomishan to Joibar is investigated in terms of subsidence and uplift using radar remote sensing techniques to determine the active tectonic zones of the coast in terms of temporal and spatial changes.

    Materials and Methods

    The Eastern Caspian Plain is the border between the Caspian Sea and West Gorgan and includes the cities of Gomishan, Bandare Turkman, Bandare Gaz, Gulugah, Khazarabad, and Joybar. The absolute height of the Caspian Plain along the coastline is determined according to the sea level, based on the hydrographic data of the Baku station, since 1850, the Caspian sea level has varied between -25.4 and -29.4 (Abdolhi Kakrodi, 2012).The history of seismic activity in North Alborz shows that cities like Rasht, Lahijan, Amol, and Gorgan, have been destroyed many times due to destructive earthquakes (Aqhanbati, 2013). The Alborz fault is an active fault that is stretched in a clockwise direction in the southern Caspian basin.In this research, according to the desired goals and radar remote sensing techniques, a series of Sentinel-1 radar images with a suitable time and space difference (maximum 30 days and maximum 150 meters respectively) including 61 images in time from 2014 to 2021 were prepared and processed.

    Results

    The results obtained from the SBAS model indicate that the eastern part of the Caspian coast is more affected by the uplift and this trend continues up to Gorgan Bay. The Gorgan city has an uplift between 20 and 40 mm/year, which is reversed towards the coastal area, and subsidence of 10 to 52 mm/year occurs, which decreases as it approaches the coast and reaches 10 mm /year.

    Discussion and Conclusion

    According to the results obtained from radar interferometry, the eastern coast of the Caspian Sea is more affected by uplifting. The Gorgan city has an uplift between 20 and 40 mm/year, which is reversed towards the coastal area, and subsidence of 10 to 52 mm/year occurs, which decreases as it approaches the coast and reaches 10 mm/year.To verify the results obtained, the data of the Gorgan geodynamic station was used, which shows subsidence of about 90 to 100 mm in a 6-year period, which is consistent with the values obtained from radar interferometry Based on comments Shahpasandzadeh (2013) and the reports of Nazari et al (2021), active tectonics caused by the Caspian fault that indicates the horizontal geodynamic displacement diagram of Gorgan, the small area towards the north and east during this time, which is observed in the form of numerous branches with a thrust (reverse) mechanism and a right-slip component with a slope to the south in Golestan province.Considering that the main feature of the coast of the Caspian Sea is the Surface rivers and the use of groundwater is very little and also the extraction of gas, oil, and mining resources, which is another factor in the occurrence of land subsidence, does not exist in this area, and there isn’t also huge and heavy structure in the study area that affects the subsidence of the surface; so displacement in the study area is the result of active tectonics.

    Keywords: Morphotectonics, Coast, Caspian Plain, Radar Interferometry, Geodynamics
  • مجید رحیم زادگان*، مهدی محبی

    عمق برف یکی از پارامترهای ورودی مهم در بسیاری از مدل های کشاورزی، هیدرولوژی و اقلیمی است. با این حال عدم قطعیت هایی در برآورد عمق برف با استفاده از ابزار سنجش از دور نوری به دلیل محدودیت های موجود در شیوه تصویربرداری وجود دارد. از این رو هدف این پژوهش استفاده از ابزار سنجش از دور مایکروویو فعال در برآورد عمق برف در مناطق کوهستانی است. بدین منظور از روش تداخل سنجی راداری تصاویر مایکروویو فعال و اندرکنش سیگنال مایکروویو با توده برف استفاده شد. داده های به کار رفته، شامل تصاویر سنتینل 1 از رشته کوه های زاگرس در کشور ایران در تاریخ فوریه 2017، مارس 2019 و 2020 بود. همچنین، به منظور اعتبارسنجی الگوریتم پیشنهادی از اندازه گیری میدانی عمق برف استفاده شد. به منظور برآورد بهتر عمق برف، نتایج در دو کانال VV و VH با استفاده از ضریب وزنی بدست آمده از زاویه تابش محلی ترکیب شدند. مقایسه نتایج روش پیشنهادی با برداشت های میدانی نشان دهنده همبستگی 86/0 بود. همچنین مقادیر RMSE و P-Value به ترتیب 37/14 سانتیمتر و 009/0 بدست آمد. با توجه به پارامترهای آماری بدست آمده از اعتبار سنجی روش پیشنهادی، کارایی آن در برآورد عمق برف مناسب بود.

    کلید واژگان: عمق برف, تداخل سنجی راداری, سنتینل 1, زاویه تابش محلی
    Majid Rahimzadegan*, Mehdi Mohebbi

    Snow depth plays a critical role as a key input parameter in various agricultural, hydrological, and climatological models. Nevertheless, the process of estimating snow depth through optical remote sensing tools is subject to uncertainties stemming from constraints within the imaging technique. Consequently, the primary objective of this study is to employ active microwave remote sensing technology for the purpose of snow depth estimation in regions characterized by mountainous terrain. The radar interferometric technique employing active microwave imagery was utilized for the specific objective of examining the microwave signal's interaction with snow accumulation. Utilizing Sentinel 1 satellite images of the Zagros mountains in Iran during the months of February 2017, March 2019, and 2020, relevant data was acquired. Furthermore, field measurements of snow depth were conducted to validate the proposed algorithm. In order to enhance the accuracy of snow depth estimations, the data from both VV and VH channels was integrated by applying a weighting factor determined based on the local radiation angle. The comparison between the outcomes of the suggested approach and the field data revealed a correlation coefficient of 0.86. Furthermore, the calculated values for RMSE and P-Value were 14.37 cm and 0.009, correspondingly. Based on the statistical metrics derived from the validation process of the proposed technique, it demonstrated a satisfactory performance in the estimation of snow depth.

    Keywords: Snow Depth, Radar Interferometry, Sentinel 1, Local Incidence Angle
  • معصومه رجبی، شهرام روستایی، سارا مطاعی*

    بررسی و پایش میدان جابه جایی ناشی از تغییر شکل های سطح زمین از مطالعات مهم و کاربردی در مباحث مختلف ازجمله زمین شناسی، ژئومورفولوژی، ژئوفیزیکی است که در پیشگیری و رفتارشناسی سوانح طبیعی از قبیل زلزله، فرونشست و زمین-لغزش نقش به سزایی دارد. در این میان فرونشست زمین یکی از پدیده های مخرب ژئومورفولوژیکی است که می تواند خسارت-های جبران ناپذیر مالی و جانی به دنبال داشته باشد و به بسیاری از زیرساخت ها و سازه ها آسیب برساند. به همین سبب با توجه به پیامدهای مخرب این پدیده، مطالعه و بررسی و حتی ارائه مدلی برای تخمین و پیش بینی نرخ فرونشست های آینده برای مناطق مستعد فرونشست ضروری به نظر می رسد. بدین منظور روش های مختلفی برای پایش فرونشست وجود دارد که از میان آن ها تکنیک تداخل سنجی، یکی از تکنیک های مهم و قابل توجه تبدیل شده است. در این پژوهش کوشش بر این است که سری زمانی فرونشست زمین را در دشت کرمانشاه در بازه زمانی 2016 (ژوئن) تا 2021 (ژانویه) با استفاده از36 تصویر ماهواره ای Sentinel-1 و 88 اینترفروگرام حاصل از آن ،با به کارگیری تکنیک تداخل سنجی راداری تحت رویکرد طول خط مبنای کوتاه (SBAS) برآورد شود. نتایج حاصل از تحلیل سری زمانی خط مبنای کوتاه نشان دهنده ی بیشینه10سانتی متر در بخش غربی دشت کرمانشاه می باشد. بررسی ارتباط بین افت سطح آب های زمینی و میزان بیشینه فرونشست در سطح دشت خطی نبودن این رابطه را نشان می دهد. که با بررسی جنس زمین در محدوده مطالعاتی به تاثیر همزمان ضخامت رسوبات ریزدانه و افت سطح آب زیر زمینی در منطقه بیشینه پی برده شد.

    کلید واژگان: فرونشست زمین, تداخل سنجی راداری, خط مبنای کوتاه, دشت کرمانشاه
    Masomeh Rajabi, Shahram Roostaei, Sara Mataee *
    Introduction

    Investigation and monitoring of displacement field due to deformations of the earth's surface is one of the most important and applied studies in various topics such as geology, geomorphology, geophysical. Land subsidence is one of the destructive geological phenomena that can cause irreparable financial and life losses. In fact, subsidence is a morphological phenomenon that in the logical state of this phenomenon includes collapse or downward sitting of the earth's surface, which can also have a small horizontal displacement vector (Solari et al., 2018). This phenomenon has been charted as a serious crisis in most plains of the country in recent years. Therefore, identifying and reducing the consequences of subsidence phenomenon requires a monitoring system. Several methods have been proposed to accurately evaluate and measure this phenomenon, which radar interferometry technique was introduced as one of the methods of radar image processing in active remote sensing, a useful tool in monitoring the placements of the earth's surface (Sadeghi et al., 2012).So that over the past several years, the use of radar interferometry technique to evaluate and monitor land subsidence has increased and its time series algorithms such as PSI and SBAS have provided the possibility of measuring ground displacements (Abu pit et al., 2010). Therefore, in this study, we tried to estimate the time series of kermanshah plain subsidence during 2016-2021 using Sentinel 1 satellite imagery and using radar interferometry technique under small baseline length approach.

    Methodology

    Radar interferometry with artificial valve is a remote sensing technique. In which two or more radar images are used to produce digital elevation models or to map the displacement of the earth's surface. In this technique, the phase difference between two different waves is measured and this phase difference is attributed to the change in distance between the sensor and the ground target or the displacement of the earth's surface. Ideally, each interferogram should have only a phase difference caused by the displacement of the earth. For this reason, other components must be removed or deducted so that the remaining phase can be obtained only from displacement. In the above article, using radar data and using radar interferometry technique and small baseline time series analysis, the time series of land subsidence phenomenon in Kermanshah plain is monitored and measured. In this method, only visual couples are used that the vertical component of the baseline is less than the critical value of the baseline. Also, their time baseline is minimized at the same time. In this way, only interferences are formed that have good quality. Then, the results of this method, which is the average annual subsidence map in the desired period, are investigated to explain the relationship between the cause of subsidence occurring on the plain surface with changes in groundwater level and the thickness of fine sediments.

    Results and Discussion

    In order to investigate the behavior pattern of the earth surface in the long term, we used time series analysis using small baseline method. To do this, among multiple images and interferograms, 36 radar images were selected from sentinel 1 sensor at the time interval of 2016 (June) to 2021 (January) and selected by the lowest baseline of 88 interferograms that had a suitable spatial and temporal baseline and were dispersed in the interferometry process. After obtaining the interferogram images, the noises in the mapping interference must be removed so that the residual noise is only due to the displacements of the earth's surface, resulting in the average map of the earth's surface displacements in the desired timeframe. Evaluation of the obtained map indicates maximum subsidence of -100 mm/year in the western parts of the plain. Then, by preparing a map of water level drop in the plain, the relationship between these two variables was investigated, which did not show a significant correlation between them, so by examining another effective factor in the plain surface, we realized that in addition to the drop in the water level, the thickness of fine sediments should also be considered because by summing these two factors together, the surface subsidence. The earth intensifies. This is well known in the western parts of the plain

    Conclusion

    The maximum subsidence calculated between 2016 and 2021 is 10 cm, which covers an area of about 1.67% of the total area. Then, in order to explain the cause of subsidence occurring in the region, we investigated the relationship between groundwater level drop and subsidence in the region. By evaluating 54 piezometer wells in the plain, it has been observed that the maximum subsidence range is not in accordance with the maximum drop in water level. Therefore, we were looking for another effective factor in the plain surface that by studying the thickness of fine sediments (clay and silt) in the maximum subsidence range, we saw a high thickness of fine sediments which has experienced a moderate drop from the water surface about 5 meters per year. Therefore, it is not always possible to see the linear relationship between water level drop and land subsidence.investigation of steady state index showthebarchan dunes, with annual displacement rate more than 12 meters,have the maximum number and highest rates of displacement, and have the lowest steady state. Thus this group is demanding the more attention and planning requirements for stabilization of quicksand and environmental management of mobile barchan dunes.

    Keywords: Land Subsidence, Radar Interferometry, Short Baseline, Kermanshah Plain
  • مصطفی مهدوی فرد، ایوب محمدی، محمدحسین رضایی مقدم*، صدرا کریم زاده

    بررسی مورفومتری یک حوضه آبخیز نقش بسیار مهمی در ساختار زمین دارد. روش های سنجش از دور ابزار مناسبی برای بررسی و استخراج شبکه آبراهه به شمار می آیند. یکی از روش های رایج برای استخراج شبکه آبراهه و بررسی مورفومتری حوضه آبخیز بهره گیری از مدل های رقومی ارتفاعی با قدرت تفکیک مکانی زیاد است. هدف از این پژوهش، استخراج شبکه آبراهه با استفاده از مدل های رقومی با قدرت تفکیک مکانی زیاد مانند آلوس و سنتینل -1 و مدل های رقومی با قدرت تفکیک مکانی متوسط مانند اس آر تی ام و تان دم ایکس است. به منظور تهیه مدل رقومی ارتفاعی سنتینل -1 از روش تداخل سنجی راداری استفاده شد. درنهایت، برای اعتبارسنجی دقت این مدل رقومی ارتفاعی از آلوس استفاده شد. نتایج نشان دهنده آن است که مدل رقومی ارتفاعی تهیه شده از سنتینل -1 با داده مرجع در این پژوهش (آلوس) دارای همبستگی حدود 99/0 که نشان دهنده قابلیت زیاد این مدل رقومی ارتفاعی در استخراج شبکه آبراهه است. نتایج استخراج آبراهه حاکی از آن است که دو مدل رقومی ارتفاعی با قدرت تفکیک مکانی زیاد سنتینل -1 و آلوس هرکدام تعداد 9 شبکه آبراهه را استخراج کردند؛ در حالی که مدل های رقومی با قدرت تفکیک مکانی متوسط اس آر تی ام و تان دم ایکس به ترتیب توانستند فقط 7 و 6 شبکه آبراهه را استخراج کنند. بررسی ها در این پژوهش نشان دهنده آن است که برای بهبود کیفیت مدل رقومی ارتفاعی سنتینل -1 باید پارامترهای خط مبنا و همچنین اختلاف زمانی بین دو تصویر قدیم و جدید در تداخل سنجی راداری بسیار موردتوجه پژوهشگران قرار گیرد.

    کلید واژگان: DEM, تصاویر راداری, تداخل سنجی راداری, آبخیزداری, سنجش از دور
    Mostafa Mahdavifard, Ayoub Mohammadi, Mohammadhossein Rezaei Moghaddam *, Sadra Karimzadeh

    Morphometric study of a watershed plays a very important role in land structure. Remote sensing methods provide a good tool for studying and extracting stream networks. One of the common methods for extracting waterway networks and conducting a morphometric study of watersheds is the use of Digital Elevation Models (DEMs) with a high spatial resolution. The purpose of this study was to extract stream networks by using the DEMs of high spatial resolution, such as ALOS-1 and Sentinel-1, and those of medium spatial resolution like SRTM and TanDemX. To produce the DEM by using Sentinel-1 images, the InSAR method was applied. Finally, to validate the accuracy of this DEM for checking Sentinel-1 ability to extract stream networks, the ALOS-1 DEM with the spatial resolution of 12.5 m was used. The results revealed that the produced DEMs by using Sentinel-1 images had a high correlation of about 0.99 with the reference data of ALOS-1, thus showing the high capability of the DEM for extracting stream networks. The results of extracting the waterway networks demonstrated that each of the two DEMs of Sentinel-1 and ALOS-1 with high spatial resolutions could extract 9 waterway networks, while the digital models of SRTM and TanDemX with medium resolutions could only extract 7 and 6 stream networks, respectively. The studies indicated that the baseline parameters, as well as the time difference between the two Master and Slave images in InSAR, had to be highly considered by researchers to improve the quality of the Sentinel-1 DEM.

    Keywords: Digital Elvation Model (DEM), Sentinel-1 Image, Insar, Stream Extraction, Remote Sensing, Taftan
  • داود مختاری*، محمدحسین رضایی مقدم، دیانا درتاج

    فرایندهای تکتونیکی نقش مهمی در شکل گیری و تغییر لندفرم ها دارند، بنابراین توجه به این فرایندها در برنامه-ریزی های مختلف حائز اهمیت است. بعضی از مناطق از جمله زون زاگرس دارای وضعیت تکتونیکی فعالی هستند به همین دلیل توجه به فعالیت های تکتونیکی در این منطقه ضروری است. با توجه به اهمیت موضوع، در این پژوهش به ارزیابی وضعیت تکتونیکی زاگرس استان فارس از محدوده اوز تا کرموستج پرداخته شده است. در این تحقیق از تصاویر راداری سنتینل 1، مدل رقومی ارتفاعی 5/12 متر SRTM و تصاویر ماهواره ای به عنوان مهم ترین داده های تحقیق استفاده شده است. مهم ترین ابزارهای مورد استفاده در تحقیق، ArcGIS، GMT و SPSS بوده است. همچنین در این تحقیق از 10 شاخص ژئومورفیک و مدل سری زمانی SBAS استفاده شده است. این تحقیق با توجه به اهداف مورد نظر در دو مرحله انجام شده است که در مرحله اول به ارزیابی وضعیت تکتونیکی منطقه با استفاده از 10 شاخص ژئومورفیک و در مرحله دوم نیز با استفاده از روش سری زمانی SBAS، وضعیت تکتونیکی منطقه ارزیابی شده است. نتایج بررسی وضعیت تکتونیکی زیرحوضه ها منطقه از نظر شاخص IAT نشان داده است که زیرحوضه 4 با میانگین ضریب 5/1 دارای کم ترین میانگین است و از نظر شاخص های مورد استفاده، دارای وضعیت تکتونیکی فعال تری نسبت به سایر زیرحوضه ها است و در مجموع نیز زیرحوضه های منطقه از نظر اکثر شاخص ها دارای وضعیت فعالی هستند. همچنین نتایج حاصله از روش تداخل سنجی راداری نشان داده است که محدوده مطالعاتی در طی سال های 2020 تا 2022 دارای 127 میلی متر بالاآمدگی و 109 میلی متر فرونشست بوده است که میزان بالاآمدگی رخ داده را می توان به عوامل تکتونیکی نسبت داد و بنابراین می توان گفت که صحت شاخص های ژئومورفیک مورد تایید است چراکه بر اساس تصاویر راداری نیز منطقه مورد مطالعه از نظر تکتونیکی دارای وضعیت فعالی است..

    کلید واژگان: تکتونیک, شاخص های ژئومورفیک, تداخل سنجی راداری, محدوده اوز تا کرموستج
    Davoud Mokhtari *, Mohammadhosein Rezayi Moghadam, Diana Dortaj
    Introduction

    Geological processes (tectonics) are formed by forces that originate from the earth's crust and change the shape of the earth's crust. These processes create external forms and landforms such as continents, mountains and oceans, and the set of these processes is called tectonic cycle, so tectonics refers to processes, buildings and landforms. Related are to changes in the shape of the earth. In order to check the tectonic status of a region or basin, there are various methods. In the meantime, geomorphic indicators are a useful and reliable tool in evaluating tectonic activities because they can be used to identify areas that have experienced fast or even slow tectonic activities in the past. Are easily identified. The amount of new land construction activities is different in different regions of the Iranian plateau, among which, Zagros is active in terms of new land construction activities and is associated with many movements. The studies of geostructural processes will be useful for the better management of geomorphological hazards, which are important for many human activities such as the design and construction of cities, power plants, airports, military and security facilities, dams and industrial centers. Also, identifying the features of the environment, the geomorphological forms of a region and being aware of them help us to better understand the environmental capabilities and by providing this information to the authorities, they can use them in the implementation of regional planning. And local, civil planning, land use plans and in general sustainable management of the environment suitable for that area. Considering the importance of the topic, in this research, the tectonic situation of Zagros in Fars province from evaz to Karmostaj has been evaluated.

    Methodology

    In this research, the Sentinel 1 radar images, SRTM 12.5 meter high digital model and satellite images are used as the most important research data. The most important tools used in the research were ArcGIS (to prepare the desired maps), GMT (to run the SBAS time series model) and SPSS (to perform the calculations related to the indicators). Also, 10 geomorphic indices and SBAS time series model were used in this research. This research has been done in two stages according to the desired goals. In the first stage, the tectonic status of the region has been evaluated using 10 geomorphic indicators. In the second stage, using Sentinel 1 radar images and the radar interferometry method and SBAS time series, the amount of vertical displacement in the study area has been evaluated. In order to implement the SBAS time series model, first, 21 Sentinel 1 radar images related to a 2-year period (2020 to 2022) have been prepared.

    Results and Discussion

    In this research, in order to investigate the tectonic status of the studied area, geomorphic indicators and also radar interferometry method have been used. The results of investigating the tectonic status of sub-basins in the region in terms of IAT index have shown that sub-basin 4 has the lowest average with an average coefficient of 1.5, and overall, in terms of the indicators used, it has a more active tectonic status than other sub-basins. After this sub-basin, sub-basins 6 and 9 have a more active tectonic situation with coefficients of 1.6 and 1.7, respectively. Also, sub-basins 10, 2 and 3 have the highest average with coefficients of 2.2, 1.2 and 1.2, respectively, and in terms of the indicators used, they are tectonically less active than other sub-basins. They have Also, the results of the radar interferometry method have shown that the study area during the studied time period (from 12/01/2020 to 01/01/2022) had 127 mm of elevation and 109 mm of subsidence. . Examining the spatial situation of the vertical movement that has occurred indicates that a large part of the southern anticlines of Lar and Gerash cities has faced subsidence and a large part of the plains of this region has faced uplift. According to these changes, it can be said that the tectonic factor played the main role in the displacement that occurred in the region.

    Conclusion

    The results of this research have shown that the studied area is tectonically active. Also, in this research, the relationship between the amount of vertical movement of the region and geomorphic indicators has been investigated. First of all, it should be said that the correctness of the geomorphic indicators is confirmed, because based on the radar images, the studied area is tectonically active. But the remarkable thing about the results obtained from the radar images is the type of displacement that occurred and the effect on the geomorphic indicators. In fact, as it was said, the plains of the region are elevated and this problem has caused the difference in the height of the basin to decrease. Based on this, the type of vertical displacement of the region has caused some indices such as Hi, Bs, SI, S and Gi to show the tectonic activity of the region less than it is. In total, the results obtained up to this stage have shown that some geomorphic indicators show the tectonic status of the region less than the actual value.

    Keywords: Tectonics, Geomorphic Indicators, Radar Interferometry
  • سمیه عمادالدین*، مسعود محمد قاسمی، دانیال قریشی
    مقدمه

      فرونشست زمین یک پدیده زمین شناسی زیست محیطی است که باعث آسیب رسانی به نقاط جمعیتی و سکونتگاه های انسانی و خسارت های زیست محیطی، اجتماعی و اقتصادی  می شود.تکنیک تداخل سنجی راداری یک ابزار قوی  در برآورد فرونشست با دقتی در محدوده میلی متر با استفاده از مشاهدات فاز را دارا هستند.

    هدف

    یکی از مناطقی که با مخاطره فرونشست مواجه است، دشت فسا در استان فارس است که با توجه به اهمیت موضوع در این تحقیق به بررسی میزان فرونشست، مطالعه سطح آب زیرزمینی و بررسی کشت آبی و دیم منطقه مورد مطالعه پرداخته شد.

    روش شناسی:

     به منظور محاسبه فرونشست از تصاویر سنتینل رادار با فرمت (SLC) تک منظر با پوراریزاسیون (VV) جهت  محاسبه میران نرخ جابجایی استفاده می شوند. روش تداخل سنجی راداری روشی برای ترکیب تصاویر SAR گرفته شده از سنجنده های راداری ماهواره  Sentinel 1A سال های 2016 تا 2020 و همچنین اطلاعات چاه های پیزومتری موجود در منطقه اخذ و تغییرات آن ها در طول دوره 1399-1372  در نرم افزار GIS با استفاده از مدل درون یابی IDW نقشه سطح آب زیرزمینی تهیه و مورد استفاده قرار گرفته است. 

    قلمرو جغرافیایی پژوهش:

     دشت فسا یکی از وسیع ترین و مهم ترین دشت های استان فارس است که چه از نظر جمعیت انسانی ساکن و همچنین سطح زیر کشت دارای اهمیت می باشد.

    یافته ها و بحث: 

    سطح آب زیرزمینی در محدوده های دارای فرونشست زمین با افت همراه بوده است. به خصوص در روستاهای دستجه، صحرآورد و قاضی کوچک که بیشترین میزان افت سطح آب زیرزمینی را دارا می باشد و در پهنه خطر فرونشست زیاد هم قرار دارند. زمین های منطقه بیشتر شامل باغات و کشت آبی است. و با توجه به امضا طیف بدست آمده از پوشش های گیاهی منطقه مورد مطالعه نوع کشت زمین ها بر اساس دیم کاری یا کشت آبی، شناسایی شد.

    نتیجه گیری

    طبق نتیجه بدست آمده یکی از دلایل اصلی فرونشست زمین در منطقه مورد مطالعه، برداشت بی رویه از منابع آب زیرزمینی است و در نهایت با استفاده از نقشه پهنه بندی خطر فرونشست مشخص شد که به طور کلی 11401 نفر در محدوده خطر فرونشست زندگی می کنند. ضروری است سازمان ها و نهادهای متولی با اتخاذ سیاست ها و برنامه ریزی های مناسب، پیش از وقوع بحران درصدد کاهش هر گونه آسیب به سکونتگاه های انسانی، جمعیت و زیرساخت های موجود در این مناطق باشند.

    کلید واژگان: تداخل سنجی راداری, فرونشست, سنتینل1, سنتینل2, دشت فسا
    Somayeh Emadodin *, Masoud Mohammadghasemi, Danyal Ghoreishi

     Interferometric Synthetic Aperture Radar (InSAR) is a powerful instrument in estimating subsidence with millimeter accuracy. This article uses Sentinel 1A satellite data from 2016 to 2020 to monitor subsidence in Fasa plain. The results of radar interference studies showed that 24 cm subsidence occurred in the study area during the statistical period. In order to find the cause of subsidence, information of piezo metric wells in the area was collected and their changes during the period 1372-1399 were studied. According to the results, the groundwater level in areas with land subsidence has been associated with a decline. Especially in the villages of Dastjeh, Sahravard and Ghazi Kouchak, which have the highest rate of groundwater level drop and are in the zone of high subsidence risk. The lands of the region mostly include gardens and irrigated cultivation. In this regard, it can be said that one of the main reasons for land subsidence in the study area is the uncontrolled abstraction of groundwater resources

    Keywords: Interferometry, subsidence, Sentinel-1, Sentinel-2, Fasa Plain
  • صابر قاطع، توحید ملک زاده*، الهامه پورقاسمی

    یکی از انواع ناپایداری دامنه ای که هر ساله خسارات مالی و جانی فراوانی را بر زندگی انسان ها وارد می نماید، مخاطره زمین لغزش است که پیامدهای اجتماعی، اقتصادی و زیست محیطی را به دنبال دارد. حوضه بالهارود شهرستان گرمی به علت کوهستانی بودن و وجود شیب های تند یکی از مناطق مستعد وقوع زمین لغزش است. بررسی عوامل موثر در وقوع زمینلغزش و شناخت نواحی مستعد آن گامی مهم در مدیریت منابع طبیعی و رسیدن به توسعه پایدار به شمار می رود. تکنیک تداخل سنجی راداری به عنوان روش کارامد در اندازه گیری جابه جایی سطح زمین می باشد. این فناوری در بررسی مخاطرات طبیعی زمین از جمله حرکات توده ای دامنه ها، فرونشست، زلزله و فعالیت های آتشفشانی بسیار متداول شده است. در این پژوهش، به منظور شناسایی و اندازه گیری زمین لغزش از تصاویر راداری سنتیل 1 سال های 2020 و 2022 استفاده شده است. به منظور پردازش اطلاعات نیز از نرم افزار SARSCAPE استفاده شده است که بالاترین بیشترین جابجایی زمین لغزش در خلاف جهت دید ، 154/0- سانتیمتر برآورد گردید که در راستای خطوط گسلی و در مرکز منطقه مورد مطالعه مشاهده شده است. همچنین نتایج این پژوهش نشان داد که تصاویر راداری از پتانسیل خوبی برای آشکارسازی ناپایداری دامنه ها و محاسبه جابه جایی آن ها برخوردار می باشد.

    کلید واژگان: زمین لغزش, تداخل سنجی راداری, سنتینل 1, حوضه بالهارود
    saber ghateh, Tohid Malekzadeh*, elhameh pourghasemi

    One of the types of domain instability that causes financial and human losses every year is the risk of landslides, which has social, economic and environmental consequences. The basin of Balharud Shahrestan is one of the areas prone to landslides due to its mountainous nature and steep slopes. Investigating the effective factors in the occurrence of landslides and identifying the prone areas is an important step in managing natural resources and achieving sustainable development. Radar interferometric technique is an effective method in measuring ground surface displacement. This technology has become very common in the investigation of natural hazards of the earth, such as mass movements of slopes, subsidence, earthquakes and volcanic activities. In this research, in order to identify and measure landslides, Sentil 1 radar images of 2020 and 2022 have been used. In order to process information, SARSCAPE software has been used, and the maximum landslide displacement in the opposite direction was estimated to be 0.154 cm, which was observed along the fault lines and in the center of the study area. Also, the results of this research showed that radar images have a good potential for revealing the instability of domains and calculating their displacement.

    Keywords: Landslide, radar interferometry, Sentinel 1, Balharud basin
  • سمیه عمادالدین*، زهرا نظری گزیک

    در دهه اخیر فرونشست به عنوان یک مخاطره ژیومورفیک در بخش وسیعی از دشت های ایران ازجمله دشت مشهد به عنوان یکی از دشت های مهم در حال وقوع است؛ بنابراین بررسی میزان نرخ فرونشست و پرداختن به علل و عوامل تاثیرگذار درجهت مدیریت خطر، دارای اهمیت زیادی است. در این مقاله برای پایش فرونشست اتفاق افتاده در دشت مشهد، از تکنیک تداخل سنجی راداری با دقت میلی متری و از داده های ماهواره Sentinel 1A  سال های 2017 تا 2021 استفاده شده است.  نتیجه مطالعات حاصل از تداخل سنجی راداری نشان داد، در  طول دوره آماری در منطقه مورد مطالعه 64 سانتی متر فرونشست اتفاق افتاده است. درادامه درجهت یافتن علت فرونشست ، اطلاعات چاه های پیزومتری موجود در منطقه اخذ و تغییرات آن ها در طول دوره 1398-1370  بررسی شد. سطح آب چاه ها در بازه زمانی مورد مطالعه به بیشترین حد کاهش خود رسیده است. بیشترین میزان افت سطح آب زیرزمینی در مناطق مرکزی و جنوب شرقی محدوده مورد مطالعه رخ داده است که متاثر از کاهش بارندگی ، خشکسالی و زمین های برنج و باغی زیاد در منطقه و فشار بیش از حد به منابع آب های زیرزمینی در این سال ها است. به طورکلی بیشترین نرخ فرونشست در مناطق با افت شدید سطح آب زیرزمینی، بافت خاک ریزدانه و ضخامت آبرفت زیاد اتفاق افتاده است.

    کلید واژگان: فرونشست, دشت مشهد, تداخل سنجی راداری, تصاویر راداری سنتینل 1, آب زیرزمینی
    Somayeh Emadodin *, Zahra Nazari Gazik

    In the last decade, subsidence is occurring as a geomorphic hazard in a large part of Iran's plains, including Mashhad plain as one of the important plains. Investigating the subsidence rate and dealing with the causes and influencing factors for risk management is very important. Radar interferometry technique is a powerful tool in estimating subsidence with millimeter accuracy using phase observations. In this paper, 2017-2021 Sentinel 1A satellite data used in order to monitor the subsidence that occurred in Mashhad plain. The results of radar interferometry studies showed that 64 cm of subsidence occurred in the study area during the statistical period.The information of piezometric wells in the collection area and their changes during the period 1991-2019 were examined in order to find the cause of subsidence. The water level of the wells has reached its maximum decrease in the studied period. The highest drop in the groundwater level has occurred in the central and southeastern regions of the studied area. The lands of the region mostly include gardens and irrigated cultivation. In general, the highest rate of subsidence has been created in areas with a sharp drop in the groundwater level, fine-grained soil texture, and high alluvial thickness.

    Keywords: Subsidence, Mashhad plain, Radar Interferometry, Sentinel -1, Groundwater
  • رحمان ملکی، حسن خاوریان نهزک*، صیاد اصغری سراسکانرود

    فرونشست زمین یکی از بحران های بوم شناختی می باشد که به ویژه باعث خسارت به تاسیسات انسانی از قبیل شبکه های ارتباطی و ساختمان ها می شود. عوامل متعددی بر روی فرونشست زمین تاثیر دارند که  زلزله می تواند یکی از آن عوامل باشد.  تحقیق حاضر، اثر زلزله ماه نوامبر سال 2017  منطقه غرب کرمانشاه ،بخصوص در شهرستان سر پل ذهاب و شهرستان ثلاث باباجی، را بر روی فرونشست بررسی می کند. بدین منظور، جهت بررسی فرونشست منطقه از روش تداخل سنجی تفاضلی راداری و داده های ماهواره سنتینل یک استفاده شده است. پردازش زوج تصویر راداری در منطقه مطالعاتی در بازه زمانی 11/11/2017 تا 30/11/2017 نشان داد که مقدار جابه-جایی عمودی در مناطق مورد مطالعه بین 41.7 تا 43- سانتی متر می باشد. مطابق نتایج بدست آمده، متوسط جابجایی فرونشست در خلاف جهت دید، 16.3- و 33.1-  سانتی متر می باشد که در راستای خطوط گسلی مشاهده شده است. همچنین متوسط نرخ جابجایی بالاآمدگی در منطقه مورد مطالعه 17.5 و 34.5 سانتی متر در سال و در راستای دید ماهواره به دست آمده است. ارزیابی نقشه جابجایی منطقه بیانگر این است که بیشترین مقدار فرونشست در قسمت های شرق، جنوب و غرب شهرستان ثلاث باباجی و قسمت های جنوب و غرب شهرستان سرپل ذهاب بوده است.

    کلید واژگان: زلزله غرب کرمانشاه, فرونشست, تداخل سنجی راداری
    Rahman Maleki, Hassan Khavarian Nehzak *, Sayyad Asghari

    Land subsidence is one of the ecological crises that especially cause damage to human facilities such as communication networks and buildings. Many factors affect the subsidence of the earth, and earthquakes can be one of those factors. The current research examines the effect of the November 2017 earthquake in the western region of Kermanshah on subsidence. For this purpose, the differential radar interferometric method and Sentinel 1 satellite data have been used to investigate the subsidence of the region. Pair processing of radar images in the study area between 11/11/2017 and 11/30/2017 showed that the amount of vertical displacement in the study areas is between -41.72 and -42.99 cm. According to the obtained results, the average displacement of subsidence in the opposite direction of view is -304.16 and -33.1265 cm, which was observed along the fault lines. Also, the average uplift movement rate in the studied area is 17.53 and 34.53 cm per year in line with the satellite view. The evaluation of the displacement map of the region shows that the greatest amount of subsidence was in the eastern, southern, and western parts of Salas Babaji City and the southern and western parts of Sarpol-Zahab city.

    Keywords: West Kermanshah Earthquake, Subsidence, Radar Interferometry
  • فرید امیری، محمد مومنی، سهراب میراثی*

    مخاطره فرونشست می تواند عاملی در ایجاد تشدید آسیب پذیری کانون فعالیت های انسانی واقع در بسترهایی با زیرساخت مخاطره آمیز طبیعی همچون زلزله باشد. در این مقاله، برای سنجش خطرپذیری فرونشست دشت لردگان و سکونتگاه های شهری از داده های ماهواره ای و به کمک تکنیک تداخل سنجی راداری استفاده شده است. بدین منظور میزان فرونشست در یک دوره زمانی 6 ساله (از 2017 تا 2023) با استفاده از داده های سنتیننل A1 در محیط نرم افزار SNAP ارزیابی شده است. نتایج مشاهدات صحرایی و ارزیابی های انجام شده حاکی از آن است که رخداد فرونشست و به تناسب افت سطح آب در اثر استخراج بیش از حد آب های زیرزمینی بوه است. داده های به دست آمده از چاه های پیزومتری شهرستان لردگان و چشمه برم نشان از افت شدید سطح آب زیرزمینی از سال 86 به بعد می باشد این میزان افت آب در بعضی مناطق تا 15 متر مشاهده شده است. نتایج حاصله از داده های راداری نشان داد در طی یک دوره 6 ساله شهرستان لردگان میزان نشستی در حدود 14 تا 18 سانتی متر را تجربه نموده است این مقادیر نشست به تناسب سالانه حدود 3 سانتی متر می باشد که در حد هشدار و فراتر از حالت نرمال است. با توجه به نرخ قابل توجه مخاطره فرونشست و آسیب هایی که این پدیده ممکن است ایجاد نماید، مدیریت صحیح برداشت آب زیرزمینی امری ضروری به نظر می رسد. فاجعه بارترین وضعیت محتمل برای این منطقه، هم زمانی سانحه نشست زمین با زمین لرزه است.

    کلید واژگان: فرونشست, لردگان, تداخل سنجی راداری, افت آب
    Farid Amiri, Mohammad Momeni, Sohrab Mirassi *
    Introduction

    The risk of subsidence can be an important factor in increasing the vulnerability of the center of human activities located in areas with natural hazardous infrastructure such as earthquakes. In recent years, this phenomenon has caused a lot of damage to the plains and cities of Iran, especially to residential buildings, plains and agricultural lands located in Chaharmahal and Bakhtiari provinces. Therefore, monitoring the amount of subsidence and dealing with its influential causes in order to control and manage its vulnerability is of particular importance. So far, various methods have been used such as using GPS, precision instrument alignment and radar interferometric method to measure land subsidence. In the meantime, the radar interferometric method is an up-to-date and effective technique for measuring changes in the earth's surface worldwide. In this article, satellite data and radar interferometric technique have been used to measure the subsidence risk of Lordegan plain and urban settlements. For this purpose, the amount of subsidence in a period of 6 years (from 2017 to 2023) has been evaluated using Sentinel A1 data using SNAP software. The results of field observations indicate that the occurrence of subsidence and proportionally the drop of groundwater level is due to excessive extraction of underground water. The data obtained from the piezometric wells of Lordegan city and Barm spring indicate a sharp drop in the underground water level since 2008. The amount of groundwater dropping has been observed in some areas up to 15 meters. The results obtained from the radar data showed that during a 6-year period, Lordegan city has experienced an amount of subsidence of about 14 to 18 cm. These subsidence amounts are about 3 cm per year, which is at the warning level and beyond the normal state. So, accurate management of the withdrawal of underground water seems essential by considering the significant rate of subsidence and its risk.

    Methodology

    Radar images obtained from virtual aperture radars (SAR) with the ability to measure the length of the vector from the sensor to the ground surface, are widely used in measurements related to the preparation of digital elevation maps. The technique used in this method is known as radar interferometric technique (InSAR). In radar interferometry, the phase obtained from two images taken from a certain area is interfered to produce an interferometer. In fact, the interferogram is the different product of two radar images. In the interferometry method, the mixed radar images that have the return phase values from the complex to the sensor are combined with each other and an image called the interferometer is produced. Hence, interference is obtained from the phase difference of two images taken at two different times, which are geometrically precisely matched. By using the phase difference information available in the interferometer, which indicates the distance difference between the sensor and the object, it is possible to prepare the deformation variable of the earth's surface or earth's topography. In this research, C-band radar images of the European Space Agency's Sentinel-1A satellite were used in the period of 02/05/2017 to 01/29/2023 at the level of a SLC and in IW mode with high resolution with VV polarization. In addition, in the data processing stage, sub-band IW1 and segment 2 to 3 images were used.

    Results and Discussion

    The radar interferometry method measures changes in the earth's surface along the line of sight of the satellite. Due to the fact that the major changes in the land surface in subsidence are in the form of height changes, the displacements extracted by the radar interferometric method can be converted into height changes by ignoring the horizontal changes in the ground surface and depicting them in the vertical direction. Each interferogram individually only contains surface changes in one time interval. By using a number of interferograms along with time series analysis, surface changes can be examined over time. Analysis of time series using radar interferometric method is a suitable method for estimating the rate of land surface changes in high spatial resolution. By having two images with different time intervals from satellite images, the rate of subsidence and vulnerability of an area can be calculated at any point and date with the radar interferometric method. It is worth mentioning that the radar interferometry technique is one of the most up-to-date and accurate tools for calculating the rate of land surface changes in the world and is being used all over the world.

    Conclusion

    In this article, using the radar interferometric technique, the state of the subsidence phenomenon in Lordegan city and the damages caused around the Barm spring in Lordegan city have been discussed. In summary, the most important results obtained are:• The results obtained from the rainfall data and different hydrographs of the plain showed that, the amount of rainfall and the level of underground water have significantly decreased since 1986, for example, the level of underground water has decreased from a depth of about 15 meters from the ground surface to a depth of about 33 meters. The results of the radar interferometry technique to depict the range of subsidence, showed that the total maximum amount of subsidence between the years 2017 and 2023 was about 18 centimeters, which is about 3 centimeters of annual subsidence. based on the evidence and investigations carried out on the Barm spring in Lordegan city, it was determined that the volume of water spring has significantly decreased. It should be noted that the construction of heavy structures and other constructions near the spring has also affected the water flow and the reduction of the flow of this spring. In recent years, numerous damages have appeared in the city and around the Barm spring, for example, the appearance of numerous and annual cracks on the streets and the path of the old aqueducts, cracks and damage to the stone walls around the spring, damage to buildings.

    Keywords: subsidence, Lordegan, Radar interferometry, water level drop
  • موسی عابدینی*، لیلا آقایاری، الناز پیروزی

    یکی از مخاطرات پیش روی بسیاری از مناطق کشور ایران، مخاطره فرونشست می باشد و با توجه به اهمیت موضوع، پایش نرخ فرونشست و پرداختن به عوامل تاثیر گذار جهت مدیریت این خطر، دارای اهمیت است. شهرستان نمین نیز، در سال های اخیر یکی از مناطق مستعد جهت مخاطره فرونشست می باشد. لذا؛ هدف از این پژوهش، ارزیابی فرونشست در این شهرستان، با استفاده از تکنیک تداخل سنجی راداری و تصاویر سنتینل 1 (در بازه زمانی 2016 و 2021) و سپس پهنه بندی مناطق مستعد فرونشست با بهره گیری از الگوریتم چند معیاره آراس، می باشد. نتایج مطالعه، در بازه زمانی مورد بررسی، 37/0 میلی متر فرونشست را در شهرستان نمین نشان داد و بیشترین مقدار فرونشست در بخش مرکزی و شمال غرب و شمال شرق شهرستان، متمرکز است. با توجه به نتایج حاصل از پهنه بندی خطر فرونشست؛ معیار های افت سطح آب و کاربری اراضی به ترتیب با ضریب وزنی 186/0 و 168/0، مهم-ترین عوامل دخیل در ایجاد خطر فرونشست محدوده مطالعاتی می باشند و به ترتیب 01/168 و 31/222 کیلومتر مربع از محدوده دارای احتمال خطر بسیار زیاد و زیاد می باشد که پتانسیل نسبتا بالای این شهرستان از لحاظ فرونشست را نشان می دهد. به نظر می رسد، نتایج مطالعه حاضر، می تواند به مدیران سازمانی و برنامه ریزان منابع اراضی و خاک در زمینه حفاظت و مدیریت منابع آبی و جلوگیری از تخریب سرزمین کمک شایانی نماید

    کلید واژگان: : پهنه بندی, تداخل سنجی راداری, تصاویر سنتینل 1, فرونشست
    Mousa Abedini *, Leila Aghayary, Elnaz Piroozi

    As a morphological phenomenon, land subsidence is a type of change in the shape of the earth's surface, which is associated with a vertical deformation or downward movement of the earth's surface, as well as the gradual settlement or removal of surface materials. The phenomenon of subsidence is due to various causes, including natural factors such as earthquake, volcanoes, fault activities, subsidence due to rising sea levels, dissolution in rocks or following human activities, including; Indiscriminate removal of fluids from the ground, such as; Water, oil and gas occur. The environmental consequences of the subsidence phenomenon are irreversible, costly, and destructive, and include creating a gap on the surface of the earth, damaging human structures, etc. Foundations, streets, bridges, roads and power and sewage transmission lines, destruction of irrigation systems and fertile agricultural soils and damage to wells. According to the statistics announced in Iran, the adverse effects caused by subsidence are not low and are rapidly developing and spreading in different plains across the country, and the lack of timely management and control of its factors can cause loss of life. And leave an irreparable loss.

    Methodology

    In this research, the images of Sentinel 1, which captures images in the C-band range of microwaves, have been used. Then the necessary processing was done through the SARSCAPE 5.2 plugin in ENVI 5.3 software and the technique used in this research to determine the amount of subsidence is the differential interferometric method with the combined opening of two frequent or non-frequent passes. In radar interferometry, the phase difference of two images from a specific time zone and baseline is determined. To zone the risk of subsidence, in the stage of data collection, the influencing components must first be specified and the required data and information must be collected and classified based on them. For this purpose, in this study, first, the effective factors (including slope, lithology, land use, precipitation, distance from the city and village, distance from the river, distance from the fault, and drop in the underground water level), according to the natural and human conditions of the region was identified. In the next step, information layers related to each of the factors were prepared in the geographic information system environment. In the next step, the weighting of the investigated factors was done according to the Critic method, and the final analysis was done using the Aras method.

    Results and Discussion

    After the interferometry steps, the phase difference has been converted into vertical displacement in the metric system. During the surveys conducted, the amount of subsidence between the years 2016 and 2020, during the last 5 years, shows that according to the above map, the highest amount of subsidence in the central, north-western, and north-eastern parts, amounting to 0.37 mm, it is concentrated. Investigation and analysis of land use and subsidence map and field studies confirm the maximum occurrence of subsidence in agricultural areas, and urban and rural areas, respectively. The presence of fertile plains and the flow of the Qarasu river in Namin city has provided a good opportunity for agricultural and animal husbandry activities, and the areas with agricultural land use have a high potential for subsidence due to the exploitation of underground water areas. After extracting the maps of each of the criteria and applying the relevant weights obtained by the Critic method and by implementing the different stages of the Aras technique, the maps of the subsidence risk zoning in 5 categories from very high to very low risk The risk is achieved. According to the result of using the Aras method, 168.01 square kilometers of the range area is in the very high-risk class and 222.31 square kilometers is in the high-risk class. Most of the high-risk and high-risk class in terms of the possibility of subsidence is located in the central and semi-western parts. Examining the high-risk and high-risk points introduced by the Aras algorithm shows; In terms of the criteria of land use, agricultural use, urban and industrial areas account for the largest percentage of the area of areas with very high and high risk. According to the land use map of the study area, a major part of the city's land has been allocated to agricultural use, which has caused overexploitation of the underground water table in recent years. In addition, a large part of the water needed for drinking and the industrial sector is also supplied from underground water sources, and this, in turn, is involved in the reduction of the water level and the increase in the risk of subsidence in the studied area.

    Conclusion

    The evaluation of the subsidence rate of the region shows that the highest subsidence rate was in the central, north-west, and north-east areas of the range and the results show that the trend of the groundwater level drop is consistent with the subsidence rate and in the areas where the water level drop is the highest. has existed, the amount of subsidence has also been higher. According to the results of subsidence risk zoning; The criteria of water level drop, and land use, respectively, with a weighting factor of 0.186 and 0.168, were assigned the most weight, and therefore, it can be said that the most important factor involved in increasing the amount and potential of subsidence in the study area of exploitation. It is a waste of underground water. Finally, it can be acknowledged that because land subsidence can cause irreparable financial and human losses, long-term solutions in the form of modifying water resources management methods and short-term solutions in the form of prevention From extraction of underground water tables, creating of underground dams to increase the water level, curbing surface water and implementing artificial feeding plans, confiscating unauthorized drilling equipment, preparing and installing smart meter devices, organizing drilling companies, strict control of water consumption and change The consumption pattern should be taken into consideration by relevant officials as well as residents.

    Keywords: Zoning, Radar interferometry, Sentinel images 1, subsidence
  • حمید گنجائیان، مجتبی یمانی*، ابوالقاسم گورابی، مهران مقصودی

    امروزه مخاطرات ناشی از جابجایی زمین نقش اساسی در مدیریت محیط طبیعی و جوامع انسانی دارد. تحقیق حاضر با استفاده از روش تداخل سنجی راداری به ارزیابی میزان جابجایی عمودی زمین در یکی از مهم ترین دشت های ایران (کرمانشاه) و تاثیر زلزله بزرگ 21/08/1396 ازگله پرداخته است. در این راستا از تصاویر سنتینل-1 مربوط به سه بازه زمانی 24/11/2016 تا 07/11/2017 (قبل از زلزله) و 07/11/2017 تا 19/11/2017 (قبل و بعد از زلزله) و همچنین 24/11/2016 تا 19/11/2017 (بعد از زلزله) استفاده شده اند. در این تحقیق ابتدا میزان جابجایی بازه زمانی اول با استفاده از روش سری زمانی SBAS (13 تصویر) محاسبه شده است. سپس با استفاده از 2 تصویر قبل و بعد از زلزله، میزان تغییرات ناشی از زلزله ارزیابی شده است و در نهایت با استفاده از روش سری زمانی SBAS (14 تصویر) میزان تغییرات بازه زمانی سوم محاسبه شده است. نتایج ارزیابی ها بیانگر است که محدوده مطالعاتی در بازه زمانی اول بین 107+ تا 40- میلی متر، در بازه زمانی دوم (قبل و بعد از زلزله) بین 22+ تا 46- میلی متر و در بازه زمانی سوم بین 102+ تا 33- جابجایی داشته است. با توجه به میزان بالاآمدگی قابل توجه محدوده مطالعاتی در طی دوره زمانی مورد مطالعه، پیشنهاد می گردد که در بررسی میزان جابجایی عمودی هر منطقه باید نقش عوامل تکتونیکی، از جمله زلزله ها را مورد توجه قرار دارد.

    کلید واژگان: دشت کرمانشاه, تداخل سنجی راداری, نوزمینساخت, زلزله ازگله, SBAS
    Hamid Ganjaeian, Mojtaba Yamani *, Abolghasem Goorabi, Mehran Maghsoudi
    Introduction

    The shape of the earth changes over time and these changes can be periodic or non-periodic. Land deformation may be related to tectonic processes such as earthquakes, faults, volcanoes, landslides, and anthropogenic processes such as mine activity and groundwater exploitation. Subsidence and uplift is one of the most important changes in the shape of the earth. Which is directly related to the tectonic status of the areas. Which is directly related to the tectonic status of the areas. The land of Iran as part of the active alpine-Himalayan tectonic zone has been affected by numerous tectonic activities over time, with the emergence of the Zagros-Makran and Alborz-Kope-Dagh mountains in the Iranian plateau due to the Arabian-Indian Plateau drifting from the landforms resulting from this convergence. Kermanshah plain is also active in tectonic terms due to its location in folded Zagros, therefore it has a lot of potential for the displacement of the Earth's surface. Today, the calculation of ground-level displacements using radar interference technology includes unique capabilities in terms of dimensions, cost, time and accuracy compared to other measurement techniques. Accordingly, in the present study, radar interferometry method was used to assess the amount of subsidence and uplift of Kermanshah Plain and the correlation of this displacement with the earthquake in Kermanshah on 21/08/1396.

    Materials and Methods

    Nowadays, calculation of displacements occurring on the surface using radar interferometry technology has unique capabilities in terms of size, cost, time and accuracy compared to other measurement techniques. Therefore, in the present study, using radar interferometry method and SBAS time series, the vertical displacement rate of Kermanshah plain and its relationship with 7.3 earthquake of Kermanshah Ezgele have been investigated. In this study, the displacement rate was calculated for three periods:-the first time in the history of 11.24.2016 to 11.07.2017 and includes 13 image Sentinel 1.Second period is from the date of 07/11/2017 to 11/19/2017 (before and after the earthquake). The third time frame selected to assess the impact of the earthquake on the process of changes and calculations for different purposes is from 24/11/2016 to 19/11/2017 (including 2 images).

    Discussion and results

    The results show that the Kermanshah herd earthquake has a direct role in the vertical displacement of Kermanshah plain. The result of calculating the vertical displacement in the first period indicates that the northwest and southeast areas of Kermanshah urban area have subsided and the northeast and southwest elevations have been elevated, but this trend has changed due to the earthquake of the Ezgele, So that the earthquake of the Ezgele has increased many parts of the study area, especially its southern regions, and has also subsided in the northeast areas of the study area, so the results in the third time period have been very variable, It is concluded that the Kermanshah northeast highlands, which had been uplifted during the first period, were associated with a subsidence due to the Kermanshah herd earthquake. Also the southeastern areas of Kermanshah urban area which had subsided in the first period, Due to the direct impact of the earthquake from the Ezgele, it has been experiencing an uplift in the third period. Therefore, it can be said that the earthquake of the Ezgele, while changing the vertical displacement process of Kermanshah plain, can affect the results of different calculations in this regard.

    Conclusion

    In this research, in order to investigate the factors affecting this displacement, three time intervals were used to evaluate the vertical displacement of the area. The results indicate that the range of studies ranged from +107 to -40 mm. Given that the amount of positive displacement (uplift) was higher than the negative displacement (subsidence) and also the tectonic factors, the main cause of the displacement can be attributed to the tectonic factors, however, other factors such as groundwater depletion can affect the rate of subsidence in the northwest and southeast of Kermanshah urban area. Evaluation results in the second time period indicate that the study area had a vertical displacement of between +22 to -46 mm during the 12 day period before and after the earthquake, which could be attributed to the short-term period. Directly attributed to the earthquake of the Ezgele. The third study period also had a range of displacements of +102 to +33 mm, but the important and significant point in this period was the impact of the earthquake of the herd on the extent and trend of displacement in the study area. In fact, the results show that in the first period, the northwest and southeast areas of Kermanshah metropolitan area have subsided and the northeast and southwest areas have risen, while the northeast Kermanshah highlands have subsided. The first time has been uplift, during this period has been associated with subsidence due to the Kermanshah Ezgele earthquake. Also, the south-eastern areas of Kermanshah metropolitan area which had subsided in the first period, due to the direct impact of the earthquake from the Ezgele, in the third period has been rising. Therefore, it can be said that the earthquake in Kermanshah plain, while changing the vertical displacement process, can affect the results of different calculations in this regard.

    Keywords: Kermanshah Plain, Nontectonic, Ezgeleh earthquake, SBAS
  • مهوش نداف سنگانی، سیدرضا حسین زاده*، خوزه فرانسیسکو مارتین داک، مهناز جهادی طرقی، ناصر حافظی مقدس

    معدن کاری سابقه ای طولانی دارد و در طیف گسترده‎ای از محیط‎های ژیومورفیک رخ می‎دهد. میزان تغییراتی که این فعالیت‎های معدن کاری در مورفولوژی و محیط معدنی به وجود می‎آورند گاه به اندازه‎ای است که محیط اطراف را دچار تغییرات اساسی و خسارات فراوانی می‎کند و ازاین رو این تغییرات نیازمند پایش دقیق است. از اوایل دهه 1990U تداخل سنجی راداری به صورت ابزاری مفید در مطالعه تمامی پدیده‎هایی که سبب تغییر سطح زمین می‎شوند، مطرح شده و به کار رفته است؛ بدین معنا که اگر سطح زمین بین دو تصویر راداری تغییرشکل بیابد، می‎توان نقشه جابه جایی سطحی را با وضوح و دقت میلی‎متری ایجاد کرد. این مقاله یافته‎های حاصل از اجرای روش SBAS روی سری زمانی مجموعه داده های سنتینل - 1 برای شناسایی تغییرشکل های سطحی، در معدن سنگ آهن سنگان - خواف به منزله یک معدن سطحی روباز را گزارش می‎دهد. معدن سنگ آهن سنگان از بزرگ ترین و غنی ترین ذخایر سنگ آهن در خاورمیانه و ایران است. این معدن، براثر برداشت و استخراج سنگ آهن، دچار تغییرات فراوان توپوگرافی و ژیومورفولوژی شده است که این تغییرات می‎تواند سبب تشدید فرایندها و مخاطرات ژیومورفولوژیکی شود. برای تخمین و به دست آوردن مقدار تغییرشکل سطح زمین، از 48 تصویر SAR از معدن سنگ آهن سنگان استفاده شده است. این تصاویر با استفاده از ماهواره سنتینل - 1 آژانس فضایی اروپا به دست آمد. سری زمانی (2014-2020) حاصل از تغییرشکل در محدوده معادن پلاسری تجزیه وتحلیل شد. نتایج به دست آمده میزان متوسط جابه جایی 20- تا 35- میلی متر در سال و حداکثر میزان تجمعی تغییرات 120- میلی متر را نشان می‎دهد. بررسی نیم رخ عرضی در نواحی ابتدایی مخروط‎افکنه در معادن پلاسری، طی بازه زمانی 2014-2020، شدت تغییرات توپوگرافی را به خوبی نشان می‎دهد. برای ارزیابی قابلیت اطمینان نتایج، به دلیل نبود داده (ایستگاه GPS) در محدوده معادن پلاسری، نتایج مشتق از SBAS با مقادیر اندازه گیری شده ازطریق توتال استیشن مربوط به واحد ژیومورفولوژی کوهستان منطقه معدنی در سال های 2020 -2014 به کار رفته است. نتایج نشان داد که میزان تغییرات حاصل از داده‎های راداری با استفاده از روش SBAS، در مقایسه با داده‎های نقشه برداری زمینی، الگوی تقریبا مشابهی را طی کرده است اما تفاوت هایی نیز دارد که ممکن است ناشی از ماهیت متفاوت برداشت (در نقشه برداری زمینی، تغییرات ارتفاعی برای یک نقطه اندازه گیری می‎شود اما، در تداخل سنجی، مقدار میانگین از نقاط مجاور یکدیگر به دست می‎آید) و از همه مهم تر، وجودنداشتن داده‎ های متوالی ترازیابی در سطح پلاسری ها به منظور ارزیابی دقیق تر نتایج است.

    کلید واژگان: سنگ آهن سنگان, خواف, تداخل سنجی راداری, SBAS, سنتینل - 1
    Mahvash Naddaf, Seyed reza Hosseunzadeh *, Jose Martin, Mahnaz Jahadi, Naser Hafezimoghaddas

    In the early 1990s, radar interferometry was introduced and used as a useful tool in the study of all phenomena that cause land surface deformations. If the land surface deforms between two radar images, a surface displacement map can be created with millimeter resolution and accuracy. This paper reports the findings of the Sentinel1 –A data time series results using the SBAS algorithm to detect surface deformation in the Sangan iron ore mine. Sangan Iron Ore Mine is the largest open pit iron ore deposit in the Middle East. Due to mining activities, this mine has undergone many changes in terms of topography and geomorphology, which can intensify geomorphological processes. To detect and obtain the amount of land deformation, 48 SAR images of Sangan iron ore mine obtained by the European Space Agency's Sentinel 1-A satellite were used. The time series (2014-2020) obtained from the deformation in the range of placer mines were analyzed. The results show the average displacement rate of -20 to -35 mm per year and the maximum cumulative rate of deformations of -120 mm. Investigation of the cross-section in the two parts of the apex and the center of the alluvial fan in the placer mines during the period 2014-2017 shows the topographic changes well. To evaluating the reliability of the results, the results derived from SBAS have been compared due to the lack of data in the range of placer mines with the values measured by the total station related to the mountain unit in the years 2020-2014. The results showed that the rate of deformations from radar data using the SBAS algorithm compared to the leveling data has followed a similar pattern. However, there may be some error due to the different nature, ie in the leveling of elevation deformations measured for a point, but in interferometry the average rate is obtained from adjacent points.

    Keywords: Sangan-Khaf, Iron ore, Radar Interferometry, SBAS, Sentinel 1-A
  • محمد حسین متدین، مهرداد اسفندیاری، ابوالفضل معینی، علی محمدی ترکاشوند*
    در سال های اخیر، پدیده بازگشت ناپذیر فرونشست زمین، باعث بروز مخاطره جدی محیطی در دشت های مختلف ایران از جمله دشت گرگان شده است. هدف از این پژوهش بررسی و تحلیل عوامل موثر در بروز فرونشست در دشت گرگان بود. روش تحقیق شامل دو بخش شناسایی مناطق فرونشست و بررسی عوامل و پارامترهای موثر و ارزیابی میزان تاثیر هرکدام بود. در بخش شناسایی، از تکنیک تداخل سنجی راداری استفاده شد که مبنای آن مقایسه فاز گرفته شده از دو مجموعه داده رادار از یک منطقه در دو زمان مختلف و با ایجاد اینترفروگرام است که قادر به اندازه گیری تغییرات سطح زمین در دوره زمانی است و در بخش بررسی عوامل موثر، نحوه تعیین و تحلیل پارامترهای موثر همچون میزان افت سطح آب، جنس و ضخامت لایه های خاک به خصوص لایه های ریزدانه خاک موردبررسی قرارگرفت. نتایج تحلیل داده های ماهواره ای بیانگر آن است که منطقه به طور پیوسته در حال نشست است. نقشه سرعت میانگین تغییر شکل در راستای خط دید ماهواره که از تحلیل سری زمانی به دست آمد، آهنگ فرونشست را 14 میلی متر در ماه (169میلیمتر در سال) نشان داد. محدوده فرونشست شناسایی شده تقریبا روند شرقی- غربی دارد که با روند ساختارهایی نظیر خزر همخوانی دارد. نمودارهای تراز سطح آب و میزان بارندگی این محدوده در سال های 1385 تا 1389 علیرغم نوسانات فصلی، روند نزولی نشان می دهند و تحلیل پارامترهای موثر، نشان می دهد که نشست، به دلیل افت یکسان آب و یا ضخامت یکسان لایه ریزدانه در اعماق مختلف، متفاوت می باشد.
    کلید واژگان: علل فرونشست, تداخل سنجی راداری, آب های زیرزمینی, دشت گرگان
    Mohammad Hossain Motedayen, Mehrdad Esfandiari, Abolfazl Moeini, Ali Mohammadi Torkashvand *
    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
    Keywords: Subsidence Causes, Radar Interferometry, Groundwater, Gorgan plain
  • صمد فتوحی*، حسین نگارش، رقیه دلارام، مسعود سیستانی بدوئی، محمد ذبیحی نژاد

     کلوت ها و ریگ یلان مهم ترین پدیده های ژیومورفولوژیکی بیابان لوت هستند که در منطقه فعال فرسایشی هیدرو-ایولین و ایولین قرار داشته و هرساله دچار تغییرات ژیومورفولوژیکی قابل توجهی می شوند. در تحقیق حاضر با استفاده از RS و GIS اقدام به آشکارسازی سیکل فرسایش در محدوده کلوت ها، ریگ لوت و محدوده انتقال بین آن ها شده است. نتایج به دست آمده در فاصله زمانی یک ساله با استفاده از فن تداخل سنجی تفاضلی راداری بین داده های رادار ماهواره سنتینل1 نشان داد که در محدوده کلوت ها (منطقه برداشت)، بیشترین میزان حفر مربوط به نیمه شمالی این منطقه بوده که از قسمت های شمالی یعنی محدوده گسترش یاردانگ ها به میزان 4/2 سانتی متر تا قسمت های مرکزی به میزان 3/0 سانتی متر برداشت شده است. نیمه جنوبی این منطقه نیز به غیراز دالان های کلوت ها و سطوح هموار که محل انباشته شدن رسوبات است، تا 002/0 سانتی متر مورد حفر قرارگرفته است. در بیشتر قسمت های شمالی محدوده مرکزی (محدوده انتقال) فرآیند حفر رسوبات به میزان به 3/2 سانتی متر می رسد. اما در قسمت های جنوبی این محدوده، انباشته شدن رسوبات چشم گیر هست که حداکثر آن تا میزان 4 سانتی متر در جنوب شرق این محدوده قرار دارد. در محدوده ریگ لوت (منطقه نشست) نیز کاهش 4 سانتی متری ارتفاع تپه های ماسه ای در بخش های غربی و شمال غربی و همچنین افزایش 5 سانتی متری ارتفاع آن ها در قسمت های شرقی و بخصوص شمال شرقی چشم گیر بوده است. بنابراین افزایش ارتفاع هرم های ماسه ای روندی غربی- شرقی داشته که ارتفاع آن در قسمت های شرقی افزایش می یابد. بنابراین در منطقه موردمطالعه، سیکل فرسایش به صورت چرخشی در جهت عکس عقربه های ساعت به فعالیت خود ادامه می دهد.

    کلید واژگان: بیابان لوت, ریگ یلان, ژئومورفولوژی, کلوت, تداخل سنجی راداری
    Samad Fotuhi *, Hossain Negaresh, Roghayeh Delaram, Masoud Sistani Bdoui, Mohamad Zabihi Nzhad
    Introduction

    Soil erosion is a phenomenon that is carried out by the wear and tear of soil on the surface of the earth and its transfer to another place by water or wind processes. This process has caused the emergence of many geomorphological forms and landforms in the world (Shayan and Zare, 2011). The extent of the world's reservoirs is large and these areas have active dynamics due to the instability of sands and undergo many geomorphological changes in a short period of time. There are many wind landforms of compression and erosion type in Lut desert. These geomorphological and geological phenomena are one of the most important natural attractions of the Lut plain and desert, which can be said to be rare or unique in the world. Landforms such as huge sand dunes and pyramids, which are unique in their kind in the world, have a very high ability to attract different tourists, including adventure tourists, scientific tourists, educational tourists, and other tourists (Maqsoudi et al. 2004). In this research, the Dayvis erosion cycle has been investigated in the Lut desert geoforms using differential radar interferometric techniques and the collection and deposition points have been revealed.

    Methodology

    In order to reveal the harvesting, transportation and sedimentation areas of the Lut desert world heritage, the radar data of Sentinel 1 satellite and the digital model at a height of 30 meters have been used for software processing. The radar technology that has been provided thanks to the rapid development of space technology (Ferretti et al., 2007) has been done with the radar interferometric method (DInSAR). In this research, we also used Landsat 8 satellite images to prepare a map of the study area, ASTER satellite digital elevation model (DEM) with a resolution of 30 meters to prepare a hypsometric map and radar processing, vector layers of geoscience databases, and windfalls of synoptic stations located around the study area. It has wind direction and speed information; it is also prepared from the National Meteorological Organization. Information processing has also been done in SNAP and GIS software.

    Discussion and results

    In order to reveal the harvesting, transportation and sedimentation areas of the Lut desert world heritage area, the differential radar interferometry method was used between 2019 and 2020 and the radar data of the Sentinel 1 satellite, which is of C-Band type and has the penetration of radar waves with a wavelength equal to the frequency of 405 5 GHz is used. According to the outputs, the phase difference between the two data in the Kluts has a negative trend and it is quite noticeable that it shows the erosibility of the Kluts, which is caused by the winds of the region.It should be noted that due to the resistance of Lut block to the internal forces of the earth, the effect of faults in the height changes in the bedrock of Lut block and the area of the Kluts is very small and the observed changes are only due to wind erosion. After the unwrapping process, the unwrapped layer is converted into a displacement layer and then georeferenced. The final map of the vertical displacement of Lute Kluts was drawn in a general and classified manner, which shows many changes during a year. But in general, the northern parts of Klut have more erosion resistance due to high wind speed and high erosion power. The yardangs in the northwest parts of Kluts can be a proof of this statement. Therefore, most of the area of Klots is eroding every year and these sediments have been accumulated in many parts of Rig Yalan. Middle Hamada can be considered as a transition range. In order to investigate the dominant processes in the creation of geomorphological complications in Lut, synoptic data were analyzed at Shahdad, Nehbandan and Nusratabad stations, and the gulbads of the region were drawn. According to the winds of the region, the erosion trend of the Klots from the northwest to the southeast shows a significant trend in wind erosion.

    conclusion

    Since Lot is the most important natural work of the country that has been registered globally, investigating its geomorphological complications is also one of the research priorities. These surveys allow for accurate knowledge and information about the conditions and characteristics of the region. Among these, Kluts and Rig Yalan are the most important geomorphological phenomena of Lot, which were investigated in this research. Kluts and Rig Yalan are located in the hydro-eolian region and are always subject to significant geomorphological changes. According to the investigations carried out in this research, it was found that there is an erosion cycle in the area of Klut. Rig Yalan and Middle Hamada. In the area of Kluts, the highest amount of digging was observed in the northern and central parts. In the northern part of the Middle Hamada, which was referred to as the transfer zone, it shows the digging of sediments, but in the southern parts of this region, we have sediment accumulation. In different parts of Lut sand, which is known as the sedimentation area, the accumulation of sediments has been different, so that in the western and western parts, the height of the sand pyramids has decreased, but in the eastern and especially the northern parts. The east shows the increase in height and accumulation of sediments. According to the mentioned contents, the erosion cycle in this range is rotational and in the counterclockwise direction. Among the articles that have been worked in Lut and can be cited as a confirmation of this research, is the article Thermal cyclone of Lut, Yemen, in which he mentions the existence of a thermal cyclone in Lut and the air flow in this cyclone is opposite. The hands of the clock say.

    Keywords: Lut desert, radar interferometry, Rig Yalan, Geomorphology, Klut
  • معصومه رجبی، شهرام روستایی، سارا مطاعی*

    پدیده های گوناگون طبیعی، از دیرباز، در کیفیت زندگی بشر تاثیر بسزایی داشته اند. یکی از این نوع پدید ه های طبیعی پدیده تغییر شکل و جابه جایی سطح زمین، ازجمله پدیده فرونشست، است. فرونشست پدیده ای موفولوژیکی است که تحت تاثیر حرکت فرو رو زمین پدید می آید. ویژگی های برجسته تصاویر راداری و دقت قابل قبول روش تداخل سنجی راداری در بررسی فرونشست زمین ابزار نیرومندی برای محققان فراهم آورده است. به همین سبب جهت بررسی فرونشست زمین در دشت کرمانشاه از 35 تصاویر راداری سنجنده سنتینل 1 در مدار صعودی و گذر 174 در بازه زمانی 2016 (ژوین) تا 2021 (ژانویه) استفاده شد. به منظور تحلیل سری زمانی این تصاویر جهت تهیه نقشه متوسط فرونشست سالانه در سطح دشت، تکنیک تداخل سنجی راداری تحت دو رویکرد PSI و SBAS به کار گرفته شد. نتایج نشان دهنده بیشینه 100 میلی متر فرونشست زمین در روش SBAS و 10میلی متر در روش PSI در محدوده غرب و شمال غربی دشت برای یک دوره 6ساله می باشد. در نهایت محدوده بیشینه از نظر زمین شناسی و ژیو هیدرولوژی بررسی شد. نتایج بررسی ها نشان داد که کاربری محدوده بیشینه فرونشست زمین شامل اراضی زراعی آبی و دیمی بوده، با بیشترین میزان برداشت آب در بخش کشاورزی، همراه با متوسط افت تراز سطح آب  8 متر در بازه  20ساله در چاه هایی با ضخامت زیاد رسوبات ریزدانه است. به طورکلی فرونشت زمین در سطح محدوده تحت تاثیر عوامل انسانی و طبیعی است

    کلید واژگان: تداخل سنجی راداری, دشت کرمانشاه, فرونشست زمینPSI, SBAS
    Masomeh Rajabi, Shahram Roostaei, Sara Mataee *

    Various natural phenomena have had a significant impact on the quality of human life since long ago. One of these types of natural phenomena is the deformation and displacement of the earth's surface, including subsidence. Subsidence is a morphological phenomenon that occurs under the influence of the downward movement of the earth. The salient features of radar images and the acceptable accuracy of the radar interferometric method have provided a powerful tool for researchers in investigating land subsidence. For this reason, 35 radar images of the Sentinel 1 sensor in the ascending orbit and transit 174 in the period from 2016 (June) to 2021 (January) were used to investigate the land subsidence in the Kermanshah plain. To analyze the time series of these images to prepare the average annual subsidence map in the plain, the radar interferometric technique was used under PSI and SBAS approaches. The results show the maximum land subsidence of 100 mm in the SBAS method and 10 mm in the PSI method in the west and northwest of the plain for 6 years. Finally, the maximum range was investigated in terms of geology and geo-hydrology. The results of the investigations showed that the land use of the maximum land subsidence area includes irrigated and rainfed agricultural lands, with the highest amount of water withdrawal in the agricultural sector, along with an average drop in the water level of 8 meters in 20 years in wells with a large thickness of fine-grained sediments. Is. In general, land subsidence in the area is affected by human and natural factors

    Keywords: Radar interferometry, Kermanshah plain, Land Subsidence, PSI, SBAS
  • صادق کریمی*، محسن پورخسروانی، آیدا رمضانی

    فرونشت سطح زمین از جمله مخاطرات محیطی است که در اثر عوامل مختلف ایجاد شده، و به خصوص در سال های اخیر خسارت های زیادی را به جوامع انسانی وارد نموده است. آبخوان دشت خانمیرزا نیز در سال های اخیر به صورت چشمگیر با این پدیده روبرو شده است. ایجاد درز و شکاف های وسیع در سطح دشت و خروج گاز از آنها ، مسیله بررسی فرونشست را حایز اهمیت می نماید. به همین علت پژوهش حاضر سعی دارد ضمن پایش و سنجش میزان فرونشست زمین در دشت خانمیرزا، ارتباط آن را با برداشت مازاد از منابع آب زیرزمینی ارزیابی و تحلیل نماید. بدین منظور جهت بررسی تغییرات سطح آب زیرزمینی در طی 10 سال و در دوبازه ی زمانی متفاوت از مدل زمین آمار IDW ، و برای برآورد میزان فرونشست سطح زمین از روش تداخل سنجی تفاضلی راداری و از تصاویر راداری Sentinel-1A در طی 5 سال و در سه بازه ی زمانی متفاوت استفاده شد. نتایج تحقیق حاکی از آنست که میزان جابجایی سطح زمین در بازه های زمانی مختلف، متفاوت بوده و از یک روند ثابت برخوردار نمی باشد، درحالیکه روند افت سطح آب های زیرزمینی در تمام بازه زمانی روند افزایشی داشته است. بر همین اساس طبق نتایج تحقیق ارتباط معناداری بین برداشت بی رویه از منابع آب زیرزمینی با مناطق دارای فرونشست در دشت خانمیرزا وجود ندارد.

    کلید واژگان: آب زیرزمینی, بالاآمدگی, تداخل سنجی راداری, فرونشست زمین, دشت خانمیرزا
    Sadegh Karimi *, Mohsen Pourkhosravani, Ayda Ramezani

    Land subsidence is one of the environmental hazards caused by various factors, and especially in recent years, it has caused a lot of damage to human societies. The Khanmirza plain aquifer has also faced this phenomenon in recent years. The creation of wide gaps and cracks on the surface of the plain and the release of gas from them makes the issue of subsidence important. For this reason, the present study tries to monitor and measure the amount of land subsidence in Khanmirza plain, and evaluate and analyze its relationship with the withdrawal of excess from underground water sources. For this purpose, in order to investigate the changes in the underground water level during 10 years and in two different time frames from the IDW geostatistics model and to estimate the subsidence of the land surface using the differential radar interferometric method and from the Sentinel-1A radar images during 5 years and in Three different time periods were used. The results of the research indicate that displacement of the earth's surface in different time periods is different and does not have a constant trend, while the trend of the drop of the underground water level has been increasing in the whole time period. Accordingly, according to the results of the research, there is no significant relationship between the indiscriminate extraction of underground water sources and the subsidence areas in Khanmirza plain.

    Keywords: Underground water, Uplift, Radar interferometry, Land subsidence, Khanmirza Plain
  • زهرا آزرم، حمید مهرابی*، سعید نادی
    فرونشست زمین یکی از مخاطرات طبیعی است که به صورت تدریجی اتفاق می افتد، این پدیده در اکثر مناطق ایران به وضعیت بحرانی رسیده است. عوامل تاثیرگذار بر فرونشست شامل تغییرات سطح آب زیرزمینی، جنس خاک، عمق بستر سنگی و... است. برای جلوگیری از پیشروی فرونشست باید علل رخداد آن بررسی شود تا با توجه به ویژگی های هر منطقه تصمیم گیری ها مبتنی بر واقعیت باشد. افت سطح آب زیرزمینی یکی از عوامل مهم موثر بر فرونشست است ولی به دلیل پیچیدگی ارتباط فرونشست با عوامل تاثیرگذار دیگر، نمی توان به صورت عام یک رابطه خطی مستقیم بین تغییرات سطح آب زیرزمینی و فرونشست در نظر گرفت. این تحقیق با هدف بررسی رابطه بین فرونشست و تغییرات سطح آب زیرزمینی به بررسی همبستگی بین دو پارامتر مذکور در بازه زمانی 1393 تا 1397 در منطقه اصفهان پرداخته است. در این راستا سری زمانی تداخل سنجی راداری و سری زمانی سطح آب چاه های پیزومتری در منطقه اصفهان موردبررسی و تحلیل قرار گرفت. نتایج نشان می دهد، در 12% از چاه ها، عدم همبستگی ، در 9% همبستگی ضعیف و مثبت، در 12% همبستگی متوسط و مثبت، در 48% همبستگی قوی و مثبت، در 6 % همبستگی ضعیف و منفی، در 4% همبستگی متوسط و منفی و در 9% همبستگی قوی و منفی بین میزبان فرونشست و افت سطح آب زیرزمینی وجود دارد. مقادیر همبستگی پیچیدگی ارتباط میزان فرونشست و افت سطح آب را نشان می دهد. پیچیدگی ارتباط میزان فرونشست و عوامل ایجاد آن، نشان دهنده لزوم انجام بررسی های دقیق تر و ارایه مدل های جامع تر است.
    کلید واژگان: فرونشست, تداخل سنجی راداری, تحلیل سری زمانی, سطح آب زیرزمینی, چاه های پیزومتری
    Zahra Azarm, Hamid Mehrabi *, Saied Nadi
    Land subsidence induced by soil consolidation is one of the natural hazards that occur gradually. This phenomenon has reached its critical state in most regions of Iran. Factors affecting subsidence are groundwater level depletion, land cover, soil type, elevation, slops gradient, rock bed depth, etc. The causes of subsidence should be investigated so that decisions could be based on the real characteristics of the region. Decrease in groundwater level is one of the most important factors that influences subsidence but due to the complexity of the relationship between subsidence and other factors, a direct linear relationship between groundwater level and subsidence cannot be considered. The study aimed to investigate the relationship between subsidence and groundwater changes through relationship between the two parameters in the period 2014 to 2018 in Isfahan. In this regard, the time series of radar interferometry and the time series of water levels of piezometric wells in the Isfahan were studied. The results show that in 12% of the wells, no correlation exists, in 9%, poor positive ignorable correlation, in 12%, fair positive correlation, in 48%, significant positive correlation, in 6%, poor negative ignorable correlation, in 4% fair negative correlation and in 9% there is a strong and negative significant correlation between the subsidence rate and the groundwater level. Correlation values show the complexity of the relationship between subsidence and water level depletion. Therefore, the relationship between subsidence and its causative factors requires more detailed studies and comprehensive models.
    Keywords: subsidence, Radar interferometry, Time series analysis, groundwater level, piezometric wells
  • شهناز جودکی، علیرضا تقیان*، مجتبی یمانی

    پادگانه های رودخانه ای میراثی از چینه شناسی برای درک تاثیرات متقابل تکتونیک، فرسایش و تغییرات آب و هوایی به شمار می روند. در این پژوهش، تحولات اقلیمی و نو زمین ساختی حوضه جاجرود و تاثیرات آن بر سکانس های پادگانه ای موردبررسی قرارگرفته است. نقشه های توپوگرافی، زمین شناسی، عکس های هوایی، تصاویر ماهواره ای و GPS ابزارهای اساسی پژوهش را تشکیل داده اند. ابتدا محدوده به سه بازه تقسیم شد. سپس برای بررسی تاثیرات تکتونیکی روش تداخل سنجی راداری به کار گرفته شده است. میزان جابجایی عمودی توسط روش سری زمانی SBAS تعیین و اثرات تکتونیک بر تشکیل و تحول پادگانه ها تحلیل گردید. توالی تغییرات اقلیمی و دینامیک جریان رودخانه متاثر از آن نیز بر اساس شواهد رسوب شناسی پادگانه ها بازسازی شده است. سرانجام داده ها بعد از ورود به نرم افزارهای ArcGIS، GMT مورد تحلیل قرارگرفته است. یافته ها نشان می دهند که منطقه مطالعاتی بین 103+ تا 28- میلی متر جابجایی داشته است (06/01/2016 تا 21/12/2018). مقدار بر خاستگی تحت تاثیر زمین ساخت فعال به سوی بالادست افزایش نشان می دهد. این اختلاف در مقدار بر خاستگی، در ارتفاع و توالی پادگانه ها به خوبی انعکاس یافته است. همچنین ورود جریان های یخ رفتی دیرینه در تلاقی انشعابات اصلی جاجرود و نیز وقوع لغزش های قدیمی و ایجاد دریاچه سدی در تغییرات مقطعی سطوح ارتفاعی پادگانه ها و بی نظمی آن ها تاثیرگذار بوده اند.

    کلید واژگان: پادگانه, تداخل سنجی راداری, حوضه جاجرود, کواترنری
    Shahnaz Joodaki, Alireza Taghian *, Mojtaba Yamani
    Introduction

    River terraces represent a history of river stratigraphy and provide valuable information for understanding the interactions of tectonics, erosion, and climate change. The high altitude of the Jajrood basin has resulted in extensive glacial remnants, especially the accumulation of moraines upstream of the basin. The extent of moraine depositions under the upstream basins of the Jajrood River is not evident in the structure of river terraces and they do not have a uniform elevation. Moreover, the relations of old glacial conditions in the sedimentary interference of terraces cannot be easily reconstructed and discriminated, and there is no regular order in the stratigraphic sequence and sedimentological conditions of the river terraces. The moraine deposition seemingly has had a major role in the differences in river terrace sequences from upstream to downstream of the study area, which calls for further investigation and is also addressed in this study. Many studies have delved into the analysis of the evolution of the river terraces. Other important areas of study include paleontology and sedimentology and their effects on the canal sustainability against flow dynamics. This study aimed to explore the climatic and neo-tectonic developments of the Jajrood River Basin and the role they have played in creating terrace sequences.

    Materials and methods

    This pure research investigated the role of neo-tectonic developments and climate change on the formation and evolution of terraces in the Jajrood River Basin. The research was based on analytical calculations and reports prepared through surveys as well as remote sensing methods to examine the effects of tectonics in the area. In addition, sedimentological evidence was studied to see how climate change has affected the formation and evolution of these terraces. The primary research tools were topographic and geological maps alongside aerial photographs and satellite images. Other fieldworks such as terrace morphometry using GPS measurements and sedimentological analysis helped to add insight to the findings. Then, the data was analyzed in ArcGIS. Here, the Jajrood Canyon was divided into three sections to better examine the morphogenesis of the terraces. Next, the transverse profiles and stratigraphic sections were drawn up to investigate the sedimentary strata in each section through morphometry, and then the evolution of the terraces was analyzed and reconstructed. The tectonics were studied using radar images to determine vertical displacement through the small baseline subset (SBAS) time series. Here, 27 Sentinel-1 images were used for the period from Oct. 14, 2014, to Oct. 27, 2016. which was performed using Generic Mapping Tools (GMT) in Linux OS. After preparing the interferogram maps, a map of the displacement in the study area was generated using the SBAS method (Zhao, 2013). Moreover, changes in the climate were studied using sedimentological and stratigraphic evidence.

    Result and discussion

    The research findings can be classified into two parts. First, neo-tectonics was investigated through remote sensing methods and the analysis of vertical displacement across the region. Then, the effects of these neo-tectonic processes on the genesis and evolution of terraces were examined. In the second part, the effect of climate change on terrace developments was explored using sedimentological and stratigraphic evidence. In the first part, the region's tectonics was analyzed using radar imagery. In doing so, the vertical displacement was measured using SBAS time series and 27 Sentinel-1 imagery during the period from Oct. 14, 2014, to Oct. 27, 2016. The specifications of the research images are presented in Table 1. The images were selected based on the research purpose and the baseline of the images relative to each other. The VV polarization was used for all images since co-polarizations exhibit a stronger backscatter. Some sensors have different polarizations, and images with different polarizations can inform interpretations to a great extent.After preparing the images, for measuring displacement using the SBAS method, first, the temporal and spatial baseline of the images was examined and image pairs were selected for interferogram generation (Table 2 and Figure 3), which was performed using GenericMapping Tools (GMT) in Linux OS. After preparing the interferogram maps, a map of the displacement in the study area was generated using the SBAS method. In the end, the role of morphotectonic relations in the morphogenesis (i.e., origin and development) of the terraces were examined.

    Conclusion

    These findings suggest that terraces in the Jajrood Canyon are highly heterogeneous in terms of sedimentological structures, stratigraphy, and altitude. For instance, the T3 to T1 terraces, respectively, were located 130, 90, and 80 m above the river. These terraces have also experienced three intermittent processes. These three river terraces were created through the combined effects of climate change, tectonic uplifts, and the formation of dam lakes. The results of SAR interferometry (InSAR) and fieldworks also confirm the effect of active tectonic uplift differences along the main canal. These differences reflect the differences in their morphogenetic processes. The altitude of the terraces at the Oushan River tributary (Section 1) is nearly 130 meters. However, this section's altitude downstream (near Hajiabad Village) is estimated at 90 m. This difference cannot be merely due to baseline discrepancies. Evidence indicates that a sedimentary interference originating in the lake due to a past landslide downstream of the study area (Hajiabad landslide) is the cause of the higher altitude of the terraces in this section. The terrace sequences were not the same in any of the three sections. To be more precise, there are three identifiable terrace levels in Section 1, two in Section 2, and one in Section 3. In addition to the differences in the tectonic baseline, three factors—namely climate change, moraine, and the formation of a landslide-dam lake downstream—were identified for the genetic diversity, sequence differences, and terrace sequences throughout the three sections. In addition to morphometric differences, there were great differences in the genesis of the terrace sediments. The river has contributed the most to the formation and structure of terraces and their genesis. Nevertheless, the interference of landslide-dam lake deposits, moraines, and alluvial deposits, consecutively or simultaneously, have affected particularly sections 1 and 2 through differences in flow dynamics. Meanwhile, greater uniformity can be seen upstream, particularly in the Garmābdar basin (Section 3), such that upstream terraces in this section are predominantly glacial.

    Keywords: Terrace, Interferometri, Jajrood basin, Quaternary
  • سیده راضیه کشاورز*، جلال بیاتی اشکفتکی، سید علی المدرسی

    لغزش ها از پدیده های بسیار پیچیده و در عین حال زیانبار به شمار می آیند که در اثر وقوع آنها مواد دامنه ای از سطوح شیبدار جابه جا می شود و زخم های به نسبت عمیقی در دامنه ها بر جای می ماند. وقوع چنین پدیده ای در نزدیکی عوارض فرهنگی مانند مناطق مسکونی، جاده ها و غیره موجب آسیب های مالی و تلفات جانی فراوان می شود. استفاده از سیستم های اطلاعات جغرافیایی در درجه اول و در پی آن، استفاده از فناوری تحلیل تصاویر ماهواره ای، در این بخش از مدیریت بسیار کمک کننده است. تداخل سنجی راداری D-InSAR با برخورداری از پوشش زمینی وسیع مکرر، پیوسته و نیز قدرت تفکیک زمانی و مکانی زیاد، از دقیق ترین و کم هزینه ترین فنون سنجش از دور است که برای نمایش جابه جایی های پدیدآمده در سطح زمین ارایه شده است. پژوهش حاضر به بررسی وجود زمین لغزش ها در محدوده پژوهشی روستای سرباز به کمک تصاویر راداری سنجنده سنتینل 1 و با استفاده از روش تداخل سنجی راداری در دوره زمانی 2017 و 2018 پرداخته است. پس از پردازش های مختلف در نرم افزار ENVI و افزونه SarScape، اندازه جابه جایی و زمین لغزش منطقه به دست آمد. با توجه به نتایج می توان گفت منطقه سرباز از نظر زمین لغزش فعال است. همچنین سه نقطه به منزله نقاط حساس معرفی شدند که مشخص شد در محدوده خطر متوسط رو به زیاد قرار دارند. نتایج نشان داد که منطقه سرباز در دوره 05/06/2017 تا 14/12/2017، دارای 069/0- جابه جایی یعنی نزدیک به 7 سانتی متر، در دوره 14/12/2017 تا 12/06/2018 دارای 035/0- جابه جایی یعنی نزدیک به 4 سانتی متر و در دوره 12/06/2018 تا 21/12/2018 دارای 064/0- جابه جایی یعنی 6 سانتی متر بوده است. در پایان نقشه نقاط حساس تهیه و ارایه شد.

    کلید واژگان: تداخل سنجی راداری, زمین لغزش, سنتینل 1, کاهش مخاطرات, منطقه سرباز
    Seyede Razieh Keshavarz *, Jalal Bayati Eshkaftaki, Seyed Ali Almodaresi
    Introduction

     Landslides are one of the most complex and at the same time harmful phenomena, as a result of which the slope material is moved from the sloping surfaces and relatively deep wounds are left on the surface of the slopes. A phenomenon near cultural features, such as residential areas, roads, etc., causes financial damage and many casualties. The use of geographic information systems in the first place, followed by the use of satellite image analysis technology, is of great help to this part of management. For this purpose, the D-InSAR radar interferometry technique, with its frequent, continuous wide ground coverage and high temporal and spatial resolution, as one of the most accurate and least expensive remote sensing techniques, to display the displacements that occur in the ground surface is provided. The present study investigated the existence of landslides in the study area of Sarbaz village by means of Sentinel 1 sensor radar images and using radar interferometric technique in the period of 2017 and 2018. After various processes that were done in ENVI software and SarScape plugin, the amount of displacement and landslide of the area was obtained, and according to the results obtained, it can be said that Sarbaz area is an area with a high level of activity in terms of landslides. Also, 3 points have been introduced as points with high sensitivity, which were found to be in the medium to high risk level. The obtained results showed that Sarbaz region had a displacement of -0.069 in the period of 06/05/2017 to 12/14/2017, in fact it had a displacement of nearly 7 cm, in the period of 12/14/2017 to 12 In 06/2018, the amount of displacement was -0.035, which means that nearly 4 centimeters of displacement occurred in the region, and between 12/06/2018 and 21/12/2018, the displacement in the region was equal to -0.064, which It shows that there has been 6 cm displacement in the studied area during this time period. At the end, a map of sensitive points was prepared and presented.Deformation of the soil surface is a dynamic process on the Earth's surface, this process occurs naturally or due to human intervention. One of the forms of this deformation is landslide [7]. The definition of landslide is the general and deep movements of the entire soil layer on the surface of the mother earth, which cause heavy damages every year, sometimes it is not possible to compensate for these damages, and we need to spend a lot of time and money. The speed of their operation and their extent often creates spectacular and sometimes catastrophic phenomena, and they may affect tens or hundreds of thousands of cubic meters of rock and soil in one place. This phenomenon works mostly in isolated sediments [10]. The effects of domain instability are mass movements on a small to large scale. Range movements may be minor and unique to the fall of a single piece of rock, or they may be very large and catastrophic. The damage caused by this type of movement is more in developed countries, but 95% of the deaths caused by it happen in developing countries. Landslides are among the most devastating natural disasters in steep areas, the damage to residential areas and economic infrastructure, as well as human casualties caused by landslides are increasing worldwide [9]. Iran, with its mainly mountainous topography, tectonic activity and high seismicity, diverse geological and climatic conditions, has the main natural conditions for creating a wide range of landslides [4]. By using morphotectonic indicators, it is possible to help planners by providing maps in predicting the places that will become unstable due to future earthquakes. By using morphometric analysis and using geomorphic indices and rank parameters of drainage networks, the active tectonics of a region can be investigated [5]. Among the presented methods, we can mention tachometry, leveling, short-range photogrammetry, observations from geodetic networks [GPS], radar interferometry, and lidar. Although the first use of radar data in investigating the instability of the earth dates back to the mid-1990s, in recent decades, due to the availability of radar data with a long time span compared to the past, and the development and expansion of new methods such as techniques Interferometry has drawn the attention of researchers to the use of these methods [4]. Among the remote sensing techniques, differential radar interferometry [DINSAR], which has the ability to work in all bad weather conditions and the length of day and night, is considered as one of the effective and efficient techniques in monitoring slow changes in the earth's surface [11]. Due to the fact that natural phenomena and hazards will cause damage in different regions, therefore, it is important and necessary to investigate these issues in different time frames and regions in the country. This research was conducted for the first time in the studied region. and the purpose of doing it is to investigate the amount of landslides in Sarbaz village in Isfahan province using radar satellite images, remote sensing techniques and radar interferometry. Therefore, this research is innovative in terms of being new and up-to-date.

    Materials and methods

     In the current research, in order to monitor and determine the amount of displacement caused by the movement of the sliding mass of Sarbaz village, the radar interferometric method and Sentinle-1, radar satellite images with C-band wavelength in the ascending orbit mode have been used. Radar interferometry or interferometry is the method of using the phase difference of signals returned from the earth's surface in two SAR images taken with a time delay or with parallax from a region to extract height or information related to changes in the earth's surface. In order to implement the DInSAR method, one should first pay attention to two principles between each pair of radar images (main image and secondary image), the first is the temporal baseline and the second is the spatial baseline. After choosing suitable interferometer pairs based on temporal and spatial baselines, in the next step of processing these images, and in order to remove the topography effect from the interferometer, the method of preparing the interferometer along with the digital height model was used. The output of this stage of the work is in the form of a differential interferogram in the form of a flattened interferogram in which the stationary phase and the topographic phase are removed from the interferogram. Since the flattened interferometer contains noise that lowers the visual quality of the fringes, the adaptive filter is used for this purpose.

    Discussion and Results

    Identifying areas prone to landslides and zoning the potential of landslides is very necessary and important in order to avoid these areas and implement prevention and control methods. In order to implement the DINSAR method in this research, the capabilities and quality of the radar images used to prepare the interferometer were checked by calculating their temporal and spatial baseline values. Table 1. The results of numerical processing of landslides and accumulation of sediments The amount of displacement in these maps is shown in the form of a numerical range between negative values and positive values in meters(Figure 2). The level of the range and slopes and positive values indicate the accumulation of sediments at the foot of the range and slopes. According to the maps of phase transformation to displacement of the landslide and the analysis of images in different time intervals, the metamorphosis of the landslide surface can also be explained well. Figure1. General map of landslides and accumulation of sediments According to the results obtained and determining the amount of landslides in the region, we have reached a positive correlation with the results of similar works, according to the results of similar works in the field of landslides that Sadeghi et al. (2022), Casagli et al. (2016), Hammand et al.(2019), Deming et al.(2020), it is concluded that by using remote sensing and radar interferometric technique, the amount of landslides in different areas can be determined with high accuracy and low cost. achieved and provided the results to relevant authorities to provide appropriate solutions.

    Conclusion

    In the new decade, the use of new technologies in the field of urban management as well as natural disaster management has had a growing trend. The use of geographic information systems in the first place, followed by the use of satellite image analysis technology, is of great help to this part of management. The present study calculated amount of landslides in Sarbaz village in Semiram city of Isfahan province by using Sentinel 1 radar satellite data and with radar interferometric technique. It is caused by landslides or, on a smaller scale, human activities. Negative numbers and sections indicate falls on slopes and other areas.  According to the obtained results, it can be said that Sarzab region is an area with a high level of landslide activity. Also, 3 points have been introduced as high sensitivity points, which were found to be in the medium to high risk level. The obtained results showed that Sarbaz region had a displacement of -0.069 in the period of 06/05/2017 to 12/14/2017, in fact it had a displacement of nearly 7 cm, in the period of 12/14/2017 to 12 In 06/2018, the amount of displacement was -0.035, which means that nearly 4 centimeters of displacement occurred in the region, and between 12/06/2018 and 21/12/2018, the displacement in the region was equal to -0.064, which It shows that there has been 6 cm displacement in the studied area during this time period.

    Keywords: Landslide, radar interferometric, Sentinel 1, Sarbaz region, Reduce Hazards
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