جستجوی مقالات مرتبط با کلیدواژه « sbas » در نشریات گروه « جغرافیا »

Today, the phenomenon of subsidence has affected many regions of the world, including densely populated cities in arid and semi-arid regions, and has caused a lot of damage. The phenomenon of subsidence is imperceptible and gradual, and in the long term it causes a lot of damage to agricultural lands as well as urban areas. Considering the many negative effects that the subsidence phenomenon has on human activities and man-made phenomena including buildings and facilities, not paying attention to it can be associated with many human and financial losses. Based on this, it will be very important to monitor the amount of land subsidence in order to reduce the negative effects and also to control its development process, and it is necessary to regularly estimate the subsidence process of the areas. Due to the fact that the phenomenon of subsidence occurs imperceptibly and its monitoring requires high precision, therefore, new methods should be used to monitor this risk. One of the methods that has received a lot of attention in recent years is the radar interferometry method, which has high accuracy and speed in processing information and monitoring changes in the earth's surface. Accordingly, in this research, this method is used. It will be used to evaluate the subsidence of Asadabad Plain. According to the mentioned cases, in this research, using radar images and radar interferometry method, the state of subsidence and its trend in Asadabad Plain and the analysis of the geomorphological factors affecting its occurrence have been evaluated.

Subsidence is the collapse or subsidence of the earth's surface, which occurs for different reasons on a large scale. Usually, this term refers to the downward vertical movement of the earth's surface, which can be accompanied by a small horizontal vector. In many cases, subsidence takes place imperceptibly and gradually, and it is one of the risks whose effects are visible in the long term. One of the most important effects of subsidence is a sinkhole, which can cause many human and financial losses. Usually, areas that face the risk of subsidence will also face the risk of sinkholes in the long term, so it is necessary to control the increasing process of subsidence. The geographical location of Iran has caused many parts of it to be at risk of subsidence. The Qorveh plain in the east of Kurdistan province is one of the plains that has faced the crisis of subsidence due to its hydroclimatic and geomorphological conditions. In terms of geomorphology, Qorveh plain has few limiting obstacles and this problem has provided the basis for the development of human activities including agricultural activities in this plain. Due to the fact that the average rainfall of Qorve plain is about 300 mm and this plain is facing a shortage of surface water resources, therefore a large part of the water resources needed by the agricultural lands of this plain is supplied through underground water sources and this problem causes There has been a sharp drop in the underground water resources of this plain in recent years. Due to the sharp drop in underground water resources and the risk of subsidence, it can be expected that if the current trend continues, the Qorve plain will also face the crisis of sinkholes. Due to the importance of the issue, in this research, using radar images, areas prone to sinkholes have been identified in this plain.

In this research, Sentinel 1 radar images, Landsat 8 satellite image, information related to piezometric wells in the area and SRTM 30 meters high digital model have been used as the most important research data. The most important tools used in the research are ArcGIS (in order to prepare the desired maps and final outputs), GMT (in order to implement the radar interferometry process), and ENVI (in order to prepare the land use map of the region). And Expert Choice (in order to give weight to the presented solutions). Also, in this research, SBAS time series models (to prepare the final subsidence map of the region), maximum likelihood (to prepare the land use map of the region) and AHP (to weight the proposed solutions) have been used. According to the objectives, this research has been done in 3 stages. In the first step, 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 the second stage, on the basis of the prepared map, library studies, as well as experts' opinions, the areas prone to sinkholes have been identified in Qorve Plain. After identifying the areas prone to sinkholes, the distribution of population points exposed to them has been evaluated. In the third stage, the effective factors in the subsidence of the region have been analyzed and effective solutions have been provided to control it.

Examining the state of subsidence occurred in the Qorve plain has shown that this plain has subsided a maximum of 379 mm during a period of 4 years. Therefore, it can be said that the Qorve plain has faced the maximum annual subsidence of about 10 cm. Due to the fact that one of the important effects of subsidence is the creation of sinkholes, in this research, the areas exposed to this hazard have been identified. In order to identify areas prone to sinkholes, areas that have subsidence of more than 200 mm during a period of 4 years (areas that have subsidence of more than 5 cm per year) as areas in They have been identified as prone to sinkholes. It should be noted that the selection of 200 mm was based on the subsidence of the region, the topography of the region, and library studies. According to the results, the areas adjacent to Dezaj city and the areas adjacent to Vinsar, Shekohabad and Ganji villages have a high potential in terms of sinkhole occurrence.

The location of Qorve plain has made this plain one of the critical plains in the west of the country. Due to its hydroclimatic situation, Qorveh plain is facing a shortage of surface water resources, and this problem has caused excessive use of underground water resources in this plain. Excessive use of underground water resources in the Qorve plain has caused this plain to face a severe drop in underground water resources, so that the annual average drop of underground water in many parts of this plain has been more than 1 meter. The severe drop in underground water resources has caused the Qorve Plain to face 379 mm of subsidence during the years 2018 to 2022, so the Qorve Plain is facing a subsidence crisis. Due to the fact that one of the important effects of subsidence is the creation of sinkholes, in this research, the areas exposed to this risk (areas with subsidence of more than 5 cm per year) have been identified. Based on the results, the areas adjacent to Dezaj city, the areas adjacent to Vinsar village, the areas adjacent to Shekohabad village and also the areas adjacent to Ganji village have a high potential in terms of sinkhole occurrence. Considering that sinkholes are associated with many human and financial losses, in this research, in order to control the subsidence and prevent the occurrence of sinkholes in Qorve plain, various solutions have been presented, and then, using the AHP model, the most important solutions have been selected. Is. Based on the results, planning based on the environmental capabilities of the Qorve plain with a weight of 0.288 has been selected as the most important solution, followed by the solutions of improving irrigation methods and preventing the cultivation of short-term crops, respectively, with a weight of 0.217 And 0.172 have been selected as the most important solutions.

The tectonic positioning of Iran has led to significant seismic activity in the region, particularly in the Alborz Unit. This study focused on investigating the morphotectonic status of Lavasan Sub-basins located on the southern slopes of the Alborz. To achieve this, a digital elevation model with 30-meter resolution, a 1:50,000 topographic map, a 1:100,000 geological map, and Sentinel-1 radar images were utilized as research data. The analysis employed GMT, ArcGIS, and SPSS software, along with specific indicators to assess the tectonic condition of the region. The research was conducted in two stages. Firstly, the tectonic conditions of the sub-basins were evaluated using morphotectonic indicators and secondly, the vertical displacement of the region was assessed using radar images and the SBAS time-series method. The results of the study indicated that Lavasan Sub-basins exhibited high tectonic activities with Barg and Kond basins averaging a score of 1.88 and Lavasan and Afjeh basins averaging a score of 2. Consequently, the latter basins demonstrated a more active tectonic status based on the IAT index. Additionally, the results obtained from the SBAS time-series method over a 3-year period (from 01/06/2016 to 12/21/2018) revealed a 79-mm elevation and a 14-mm depression, which could be attributed to tectonic activity, thus corroborating the accuracy of the results obtained from morphotectonic indicators.

The subsidence is one of the hazards that has posed a significant threat to many plains in the country in recent years. Asadabad Plain in Hamedan province is among those plains with a high potential for subsidence due to its hydro climatic conditions and geomorphology. Because of the importance of this issue, in this research the subsidence status of Asadabad Plain has been assessed and unlike many previous researches, the role of human factors in its occurrence has been analyzed. To do so, Sentinel-1 radar images, Landsat 5 and  8 satellite images, statistical information related to piezo metric wells in the region, and digital elevation layers were used as the primary data sources. Using the SBAS time series method, a subsidence map of the area from 2015 to 2022 was generated, followed by an analysis of the impact of groundwater depletion and land-use changes on subsidence. The results indicate subsidence ranging from 132 to 704 millimeters in Asadabad Plain during 2015 to 2022, with the highest subsidence occurring in the central regions of the plain. Considering the significant correlation (a correlation coefficient of 0.709) between subsidence and groundwater level decline, it can be concluded that one of the main causes of subsidence in Asadabad Plain is the depletion of groundwater resources. The assessment of land-use changes also reveals an increasing trend in agricultural land and human-built areas, corresponding to increased exploitation of groundwater resources and intensified land surface pressure, leading to exacerbated subsidence. Given the persistence of subsidence in this plain, remote sensing monitoring and the establishment of fixed GPS measurement stations facilitate monitoring the rate and extent of subsidence.

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.

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).

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.

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.

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.

Subsidence is a danger that threatens many plains of Iran. Qahavand plain in Hamadan province is one of the plains that is exposed to this danger due to the unfavorable hydro-climatic conditions and the type of human activities. Considering the importance of the subject, in this research, the subsidence condition of the Ghahavand plain and the factors influencing its occurrence have been investigated. According to the subject and objectives, in this research, 31 radar images of Sentinel 1 satellite, Landsat 8 satellite image and 30 meters high digital model were used as research data. The most important research tools are GMT, ENVI and ArcGIS software. This research has been done in three stages, in the first stage, the land cover map was prepared and examined. In the second stage, using the SBAS time series method, the subsidence situation of the region was evaluated and in the third stage, the effective factors in the subsidence of the region were analyzed. According to the results of this research, the Ghahavand Plain has subsided between 15 and 78 mm during a 2-year period (from 2017/01/05 to 2019/01/19). Also, the results of this research have shown that the main cause of subsidence in the region was the sharp drop in underground water resources due to the development of irrigated agricultural lands. In fact, the highest amount of subsidence in the region has corresponded to irrigated agricultural lands

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

The risk of subsidence in recent years has posed serious challenges to many cities, including cities in arid and semi-arid regions of Iran. Hamedan is one of the cities that are exposed to this risk and for this reason, this study evaluated the subsidence in the city. The data included Sentinel 1 radar images, Landsat satellite images, 30 m SRTM digital model and groundwater data. Tools also included ArcGIS, GMT, and ENVI. In the first stage, land use maps of the region for the period 1991-2020 were prepared and analyzed. In the second stage, the situation of groundwater depletion in the study area was explored, and in the third stage, using radar images and SBAS time series method, the amount of subsidence in the area over a three-year period (2017 to 2020) was calculated. The results showed that the urban area and suburbs of Hamedan annually experience one meter drop in water resources and 0.7 Square kilometers of physical development. Moreover, the subsidence rate of this area during the three-year period was between 6 to 98 mm. According to the final map, the rate in western areas of Hamadan was between 60 to 98 mm, in central areas was between 30 to 60 mm, and in a big part the city subsidence is 6 to 30 mm from its eastern regions. Considering that the highest rate of physical development of Hamedan city in recent years has been in the western suburbs of the city, it can be said that the physical development along with the decline of groundwater resources are the main factors of subsidence in this city.

Land subsidence, as one of the natural and geological hazards, can be caused by human activities such as long-term discharge of groundwater and traditional irrigation farming. In the last two decades, climate change and successive droughts, unsustainable management of water resources and overexploitation of groundwater as well as population growth have caused land subsidence in Shahriar plain in the west of Tehran province. The present study aims to monitor and estimate land subsidence using Interferometric Synthetic Aperture Radar (InSAR) approach. Moreover, it tries to investigate the relationship between groundwater level and subsidence rate. Therefore, the time series of the ENVISAT-ASAR satellite images from 2003 to 2010 were used. The Small BAseline Subset (SBAS) algorithm was applied to analyze the time series of land surface displacement and to generate the mean displacement velocity map. The findings from time series analysis of InSAR data indicate a continuous subsidence occurrence in the agricultural lands of the region. The mean velocity of deformation along the satellite line of sight (LOS) in the time period of study, shows the displacement at an average rate of -10 cm / year and a maximum rate of -27 cm / year in the Shahriar plain in the west of Tehran province. Over this time period, groundwater level decreases about 0.5 to 1.5 m in the aquifer storage at 12 observational wells located in the study area. The overall correlation between changes in groundwater level and subsidence rate was estimated circa 89.45 percent, which indicates a strong relationship between subsidence and groundwater exploitation in the region.

Land subsidence, as a natural phenomenon, is defined as the gradual subsidence or abrupt sinking of the ground surface due to the subsurface material’s compression. One of the common causes of the land subsidence formation is the overexploitation of underground aquifers. The occurrence of land subsidence due to groundwater extraction from aquifers has been studied in several researches and documented in various regions of the world. This phenomenon is known as a global problem and leads to many environmental consequences such as damaging human structures like buildings, streets, bridges and power lines, creating holes on the earth surface, intensifying floods and flooding and reduction of aquifer capacity for water storage and ultimately it poses social and economic risks for human societies. In regions with bounded groundwater aquifers, groundwater discharge causes the reduction of pore pressure and subsequently sedimentary layers are compacted and condensed. This process leads to the downward movement of the ground surface and so-called land subsidence. Surface deformation is often measured using Interferometric Synthetic Aperture Radar (InSAR) technique. Generally, InSAR technique measures the phase difference of radar waves caused by the deformation created on the earth surface in time interval between two satellite pass.

In this study, radar interferometry techniques were used to monitor, estimate and analyze time series of land displacement in the west of Tehran province. Based on the historical archive and free accessibility, ENVISAT images were identified as the best dataset to estimate the land subsidence. Therefore, the level 2 time series data product (IMS) of ENVISAT-ASAR sensor related to frame number of 2889 from descending track of 149 were acquired. The time series selection of SAR data was determined according to the availability of well depth data. In the first step, the radar interferometry method was applied by analysing all possible differential interferograms with respect to temporal and spatial baselines to detect deformation signals (in particular, land subsidence). In the next step, by selecting a set of optimal generated interferograms regarding spatial and temporal baseline and using the SBAS algorithm, the land surface displacement time series were evaluated and the mean displacement velocity map for the region was produced.

The results of using InSAR approach indicate some subsidence event in the eastern part of Shahriar and northwest and west of Eslamshahr with mean velocity of -10 cm per year. Also, the estimated maximum subsidence rate in this region is -27 cm per year. The results of time series analysis, using the SBAS algorithm, showed that the subsidence signals before 2005 occurred at a faster rate compared to the 2005 to 2010. Groundwater level data of study area for the period of 2003 to 2010 generally represents drop in groundwater levels. Due to the slope and elevation (topographic status), the wells located in the northern part of the study area are much deeper than those in the southern part. Besides, the trend of water level decline in this area has not always been descending and sometimes the water level has increased limitedly at certain times. The results indicate that the water level decline has been more severe in the north and west than in the south and east part of region. The results of correlation analysis between changes in groundwater level and land subsidence indicate a high correlation between land subsidence signals and groundwater extraction with an average estimate of 89.45%. The lowest correlation was observed in well No. 2 with a correlation of 52.11%. The highest correlation of 99.96% was observed in well No. 7. The poor correlation between water depth in observational wells and land surface subsidence signals is related to the geological properties of the area and the type of soil which ultimately causes a time delay between groundwater exploitation and subsidence signals. The results also indicate that an average subsidence of 5 to 12 cm have been occurred per 1 meter drop in groundwater level. The results of previous studies related to InSAR processing in Shahriar plain were examined to confirm the accuracy of the obtained results. The results of the time series analysis of land displacement signals to extract the spatial-temporal pattern of the region's subsidence, despite minor differences, are very similar to the results of other studies in the same region. Minor discrepancies in the estimated subsidence rate (sometimes up to 3 cm per year) can be attributed to the type of applied algorithm and radar images, as well as the considered time period.

Having recognized land subsidence phenomenon in the current study, time series images were estimated using InSAR technique in the west of Tehran province. Then, the relationship between subsidence rate and groundwater level changes in the area was investigated. The high correlation indicated that the main cause of the subsidence in this area was the overexploitation of groundwater. Also, the conformity of the spatial patterns of subsidence signals to agricultural lands in the study area indicates the relationship between subsidence event and land use. In this study, for the first time with a deeper look, the relationship between land subsidence and water underground level changes in observational wells was evaluated separately. Due to the observation of nonlinear patterns in relation to the correlation analysis between subsidence and groundwater levels in some areas of the study area, it is suggested that the geological structures of each well be separately examined and compared with the amount of subsidence in future research.

The Hamedan-Bahar plain has experienced a severe drop in groundwater levels during recent salinities, which has caused the region to be exposed to subsidence hazards. Accordingly, in this study firstly, using groundwater level information in the study area, the groundwater level in the study area was evaluated using 5 piezometers in the study area. Then, using the Sentinel 1 satellite imagery (2016/01/11 to 2017/12/19) and the SBAS time series method, the vertical displacement of the region is evaluated. Groundwater assessment results indicate that the range of studies in recent years has seen an increasing trend in groundwater levels, with water levels in some wells reaching up to 2 m / year, which has caused There has been a sharp drop in water levels in that area. Also, the results of the evaluation of the displacement rate of the area indicate that this area has been subsidence by 133/2 mm over the 2 year period. In addition, the results of correlation between annual water level decline and area subsidence indicate that there is a direct relationship between water level decline and area subsidence and the correlation coefficient of ./94 percent.

Tectonic geomorphology studies the dynamic and dynamic processes involved in shaping the present landscape. In recent years, tectonic geomorphology has been remarkably one of the major and effective tools in detecting active tectonic shapes and seismic hazard maps as well as understanding and understanding the history of the present Earth's surface measurements. Today, tectonics has proven to be an effective application in geomorphological knowledge. Quantitative measurement of landforms allows geomorphologists to investigate the role of active tectonics in landscape deformation. Tectonic geomorphology studies the landforms created by tectonic activity. Quantitative investigation of tectonically active landforms is a very useful tool in reconstructing tectonic history and understanding the evolution of landforms. To study the gradual effects of tectonics over thousands of years, one has to examine the morphological effects that have preserved them. One of the effects that responds to tectonic changes is salt diapir whose form of quantitative features can be influenced by active tectonics. The aim of this study was to identify salt diapir in Fars province and evaluate their activity using different indices. Then, using radar images and radar interferometry, the magnitude of the diapir was increased. Calculate salt and compare it with the results of tectonic indices.

This research is based on descriptive-analytical methods. The research data included 1:50000 topographic maps, 1: 100000 geological maps, 30 meters DEM SRTM , Sentinel satellite radar images, and salt diapir morphometric information through field surveys and Google imagery. Research tools include GMT software to map area displacement, ARCGIS to map, Google Inheritance to assess area status, as well as 9 indicators to evaluate salt diapir activity status. The method used in this study is to first use 9 indices Circularity (C), Elevation Index (Bh), Elongation Index (Bs), Hypsometric Integral Index (Hi) and Area Under Hypsometric Curve (y), Branch Ratio Index (BR), Average Class 1 Waterway Index (LN1), Drainage density index (Dd) and waterway frequency index (Fs) The activity status of the salt diapir is investigated and then calculated using the SBAS method of vertical displacement. After calculating different indices to evaluate the activity status of salt diapir and also preparing the vertical displacement rate map, in this step, the relationship between indices and the displacement rate map of the region is discussed.

In this study, tectonic status of salt diapir was evaluated using different indices. Since the tectonic status of each diapir was different for different indices, salt diapir were rated for each index in order to evaluate the overall diapir for all indices, In fact, scoring has been relative, and given that the diapir has been evaluated in this study, each diapir has a score of 1 to 11 in terms of tectonic status. Evaluation results show that Chalal Salt diapir with average of 7.11, Benako with 6.55 and Aliabad with 6.44 of each index have the highest score and are considered as the most active diapir Salt diapir of Pyramid with average of 5 depleted with 5.22and Nina with 5.44 points are considered as diapir with low tectonic activity. After calculating the indices, the vertical displacement rate of the region was estimated using SBAS time series method. The results indicate that the range of studies over the 2-year period has shifted from -153 to 93 mm. This indicates that the area had a maximum subsidence of 153 mm during the period studied and a maximum of 93 mm uplift.

According to the results obtained by calculating the indices, among the salt diapir, the salt pomegranate has the lowest activity and, as a result of the SBAS method, it is in the area without uplift and subsidence, Corresponds to the results of the indices. But some salt diapir, such as the Chehal Diapir, are considered to be the most active in terms of indicators, While the map shows the extent of displacement in areas without uplift and even subsidence, this indicates the impact of various factors such as groundwater loss, erosion, and etc. In view of the above, it can be said that the study area is affected by salt formations, and in some areas it has been up to 93 mm over the course of 2 years, But due to various factors such as groundwater loss in the southern part of the range, the area has been subdued, so it can be said that the vertical displacement of the area in addition to the salt formations that caused the uplift, groundwater loss and tectonic factors Caused the collapse of the region. Keywords: Salt diapir, Tectonic indices, SBAS, Larestan

The land subsidence is the descending or collapse of the land under the influence of natural and human factors. The land subsidence is one of the issues that are being exacerbated by human factors, including excessive exploitation of groundwater. Subsidence can affect many constructions and facilities, causing problems for the industry, the environment, etc. This phenomenon is one of the most important environmental hazards that have been less considered than other natural phenomena due to the low human losses. The Qorveh plain is considered as one of the plains which have been introduced as a forbidden plain in the province of Kurdistan in recent years due to the over-exploitation of groundwater. Considering the amount of groundwater level drop and its direct impact on the subsidence level of the region, the present study evaluates the subsidence rate of the Qorveh plain during the period of 2017.12.19 to 2016.01.11. In this research, in order to evaluate the status of the groundwater drop, the statistical data from the Regional Water Organization of Kurdistan province has been used, and the Sentinel-1 images and the SBAS method were used (due to the unique capabilities of this method in terms of dimension, cost, time and accuracy compared to other remote sensing techniques) to estimate the subsidence rate of the region.

In this research, first, the status of the groundwater of the Qorveh plain and the drop rate of its level has been investigated. Then, the subsidence rate of the area and its relation with the groundwater drop has been investigated. Radar interferometry and SBAS were used to evaluate the subsidence of the study area. Radar interferometry method is one of the most powerful tools for monitoring the subsidence phenomenon. By comparing the phases of two radar images taken from a region at two different times, this method can determine the land surface changes at that time interval. The phase taken from a feature on the land surface is proportional to its distance to the radar sensor. Therefore, making any changes in this distance affects the measured phase. In this research, the Sentinel-1 images (2017.12.19 and 2016.01.11) have been used to perform the radar interferometry.

The hydrograph of the alluvial aquifer of the Qorveh plain has been provided for the water years of 1966-1676 to 2010-2011. During the 24 yeas, the groundwater level fluctuations in this plain are -13.29 meters, with an annual average of -0.55 meters. The least rate of dropping in the wells is in the wells located south of the Qorveh plain, and the rate increases toward the eastern and northeastern parts. In this research, the subsidence rate of the Qorveh Plain was estimated from 2017.12.19 to 2016.01.11 using the SBAS method. The final map indicates that during this period, the study area subsided between +61 and 216 cm, with the lowest subsidence occurring in the southern areas of the Qorveh plain, which corresponding to the sedimentary heights and slopes of Badr and Parishan and the rate has increased toward the east and west of the Qorveh plain.

The results of this study indicate that Qorveh Plain has witnessed a sharp drop in groundwater level over the recent years. Considering that the southern parts of the Qorveh plain corresponds to the heights and slopes of Badr and Parishan, and the rate of exploiting groundwater in these parts is lower, the rate of subsidence is less. The plain has also subsided further towards theeastern, western and northern parts and the outlet of the Shoor River, due to the growing increase of exploitation. The results indicate that the rate of subsidence is consistent with the rate of groundwater drop so that in the southern part which corresponds to the Badr and Parishan slopes, the rate was less than 10 millimeters during the period of 2017.12.19 to 2016.01.11. The results of the SBAS method indicate that the study area had subsidence of 216 mm during the 2 years and also a 61 mm uplift. Based on the final result, the highest rate of subsidence was related to the eastern and western parts of Qorveh plain and on the outskirts of the city of Dezaj and the villages of Ghasem-Abad, Shokuh-Abad, Avangan, Ganji, and others. A series of the aforementioned factors suggests that the Qorveh plain subsides about 20 centimeters per year. This is due to the over-exploitation of the groundwater. Unlike some areas where the displacement (subsidence and uplift) is due to the tectonic conditions, the results of this study have shown that in the Qorveh plain, the subsidence has a direct relationship to the drop of the groundwater. Therefore, it is necessary to monitor the use of groundwater, especially in the agricultural sector, and the rate of the exploitation should be proportional to the amount of recharge because in addition to the water shortage problems, the continuous use of the groundwater can lead to the irreversible risks of subsidence.