Search

Land subsidence is a natural hazard characterized by gradual movement, resulting in financial losses and, occasionally, loss of life. This research employs interferometric radar techniques to study morphological changes in the Kahrez Plain aquifer. The extent of land subsidence in the Kahrez Plain aquifer is investigated using Sentinel-1 satellite imagery from 2014 to 2023. This aquifer is situated in the western subsidence of Lake Urmia and is predominantly composed of limestone lithology. The geological structure in the area comprises inclined layers and the effects of fault activity. Microscopic examinations of rocks from the region reveal dual fractures, displacement, collision, and simultaneous rotational phenomena, indicating the role of tectonics in shaping the existing structures in the area. According to the interferometric analysis results, no land subsidence has been observed in the Kahrez Plain aquifer during the study period, and the uplift ranges from 0.34 to 1.51 meters. Regional deformation, resulting from changes in landforms such as earthquakes or tectonic activities, could be a significant factor contributing to the notable uplift. [ABSTRACT FROM AUTHOR]

In the future, the risk of land subsidence due to water resources shortage crisis and improper water resources management will become more and more dangerous. It is necessary to assess and identify areas susceptible to subsidence risk and take necessary actions to reduce risks related to land subsidence. In this study, first, the risk of land subsidence was identified and evaluated using a radar interferometry method called LiCSBAS. Then, the spatial relationship between the occurrence of land subsidence hazard and effective factors such as ground elevation, slope, slope aspect, lithology, land use, groundwater decline, distance from rivers, distance from faults, topographic moisture index, and arc curvature was investigated using the random forest (RF) model. In the end, the land subsidence hazard sensitivity map was prepared after calibrating the random forest algorithm. The analysis of LiCSBAS interferometric time series data from 2015 to 2022 showed that the center of the Marvdasht-Kharameh plain and adjacent agricultural areas are continuously subsiding and the mean deformation rate map showed a subsidence rate of 11.6 centimeters per year. The results of determining the spatial relationship between subsidence occurrence and effective factors confirmed the positive impact of distance from rivers, urban and agricultural land uses, depth of bedrock (aquifer thickness), groundwater decline, and alluvial and fine-grained formations on this phenomenon. Also, the results of subsidence modeling using the random forest algorithm showed that factors such as bedrock depth, groundwater decline, land use, and geology have the greatest impact on the potential for subsidence occurrence in the study area. Also, based on the results, about 3 to 4 percent of the areas are in the very high and extremely high-risk classes of land subsidence, especially in the center and suburbs of Mervdasht. Therefore, water resources management and control and developing a systematic program to reduce subsidence risk and aquifer recharge conservation in Merudasht-Kharameh Plain is essential. [ABSTRACT FROM AUTHOR]

Due to the unique geographical and geological situation of Iran, the earthquake phenomenon imposes numerous human and financial losses on our country every year. There are solutions to reduce these losses such as identifying areas prone to earthquakes and providing practical solutions. In this regard, the present study aims to investigate the effect of changes in the subsidence rate on the trend of seismicity in plains of Tehran from 2014 to 2021. To determine the subsidence rate of the region, sentinel-1 sensor satellite data with SNAP 5.0 software was used to perform radar interferometry, and the data of 64 piezometer wells in the region from 2014 to 2021 were used to zone the groundwater level. Also, Kijko software was used to correct the seismic catalog. The results showed that there is subsidence in the Shahriar plain at a rate of 54.5 cm per year and in the Varamin plain at a rate of 65 cm per year. Accordingly, 600 thousand cubic meters change in the aquifer volume of the studied area per year leads to the minimum changes of the regional stress to the extent of 5 bar to 17 bar (equivalent to 500 to 1700 kilopascals). Also, the seismicity pattern of the region shows an increasing trend in the probability of future earthquakes on one side, and a shortening of the seismic return period in the studied area on the other side. Finally, the high consistency of the data trend in the distribution charts demonstrates the agreement of the subsidence trend and, subsequently, its effect on the seismicity trend of the studied area, which in turn indicates the effect of subsidence on the seismicity trend in the studied areas. [ABSTRACT FROM AUTHOR]

Introduction and Objective One of the important natural hazards is land subsidence. This phenomenon has also been observed in Iran due to the indiscriminate extraction of underground water resources, and unfortunately, more areas are exposed to it. The DPSIR tool or Driving Force, Pressure, State, Impact, Response framework is a tool that describes environmental problems through cause and effect relationships between human activities and the environment. This framework provides a background to combine different types of indicators and considers not only the environmental effects but also the economic and social effects resulting from changes in the status of ecosystems. The purpose of this research is to present the cause and effect relationships for the most important issues and problems of the risk of land subsidence in one of the important and critical plains of Fars province (Seydan-Farooq) and the most appropriate management responses using the DPSIR tool. and provide non-management to improve the current situation.Materials and Methods First, the problems of Seydan-Farooq Plain were determined based on library studies, asking experts and referring to the region, and based on this, possible strategies were determined. Then, the DPSIR tool was used to identify the cause and effect relationship analysis between the factors that determine the characteristics affecting land subsidence in the plain, and the DPSIR table was prepared for the risk of land subsidence in this plain. In order to prioritize and determine the importance of the problems, pressures and management strategies of the plain, a Likert scale questionnaire was used as a measurement tool and 40 experts were surveyed. Friedman's test was used to rank the items and Cronbach's alpha method was used to check the reliability of the questionnaire using SPSS version 22 software. Then Friedman's test was used for two-way analysis of variance by ranking and also comparing the average ranking of different groups using SPSS software.Results and Discussion The ranking of the items of the driving force component in Seydan-Farooq plain of Fars province showed that the range of the average values of the ratings varies from 1.86 to 4.45. The ranking of the items shows a significant difference in the items of the driving force component, so that the item "Population" with an average rating of 4.45 and also the item "Development of Industries" with an average rating of 1/86, it has been ranked first and fifth respectively. Therefore, in the "driving force" component, according to the factors: population, agricultural development, garden development, climate change and industrial development, the highest priority in intensifying the risk of land subsidence in this plain. assigned Regarding the ranking of the pressure component items, the range of the difference in the average values of the ratings in the pressure component varies from 1.25 to 5.40. The ranking of the items showed a significant difference in the items of the pressure component, so that the item "withdrawal from the underground water table in the agricultural sector" with an average rating of 5.40 and also the item "withdrawal from "Underground water table in the domestic sector" with an average rating of 1.25 has been ranked first and sixth respectively. Therefore, in the "pressure" component, according to the factors: withdrawal from the underground water table in the agricultural sector, failure to comply with the environmental rights of the aquifer, decrease in rainfall, withdrawal from the underground water table in the garden sector, From the underground water table in the industrial sector and the withdrawal from the underground water table in the domestic sector, they have assigned the highest priority in intensifying the risk of land subsidence in this plain. The average values of the ranks in the response component vary from 2.35 to 5.75. The ranking in the items of the response component also shows a significant difference, so that the item "increasing irrigation efficiency" with an average rating of 5.75 and also the item "nutrition" Point of water in the plain" with an average rating of 2.35 has taken the first and sixth place, respectively. Therefore, in the "response" component, in the order of the factors: increasing irrigation efficiency, changing the cultivation pattern, controlling the harvesting of authorized wells, aquifer operations, blocking unauthorized wells, cultural measures and spot nutrition. Water in the plain has the highest priority in reducing the risk of land subsidence in this plain.Conclusion and Suggestions Five driving forces (D) have caused six pressures (P) on the water resources of this plain, the most important of which are "withdrawal from the underground water table in the agricultural sector" and "not respecting the environmental rights of the aquifer". are The pressures, in turn, have created a disordered (S) situation (dropping of the water table) in this plain. This situation has two adverse effects (I) "land destruction" and "aquifer destruction". In order to improve the situation, seven management responses (R) were presented, the most important of which are "increasing irrigation efficiency" and "changing the cultivation pattern". In the current situation, it is not possible to stop the pressures; However, their adjustment and modification should be specially considered by planners and managers. It is worth mentioning that if these cases are not corrected, there will still be pressures (P) and will lead to more critical conditions than the existing situation (S) and finally, its effect (I), destruction of lands, aquifers. and the destruction of water and soil resources of this plain will be more. Due to the fact that the executive structure of the country's natural resources management is more in line with the components of pressure (P) and situation (S); It is suggested to develop suitable, practical and operational answers (R). It is also necessary to pay serious attention to the preventive approach in reducing the risk of land subsidence; Because, unfortunately, this matter has not been paid attention to in the country. Therefore, it is suggested to consider and implement a preventive approach that both understands the driving forces (D) and prevents the implementation of policies that cause pressure.

Land subsidence is defined as equal to the vertical displacement of the ground over a specified time. Declining water table elevation is one of the main causes of subsidence that can cause irreparable damage to surface and subsurface structures, especially in urban areas. In this research, the magnitude of subsidence due to water withdrawal from the pumping well has been estimated, and the factors affecting it have been determined. For this purpose, by collecting data from two water wells located in Kashan city, the subsidence analysis was performed based on the finite element numerical method using PLAXIS2D software. The results show that the water pumping during one year causes a decrease in the water table elevation and, as a result, the land subsidence by a few centimeters, but under a constant flow rate of water withdrawal from the well, the magnitude of subsidence in the studied wells is heterogeneous. Also, increasing the water withdrawal flow rate from wells up to 700 m3/day and the depth of wells up to 500 meters has increased subsidence, but after that, the amount of subsidence remains constant. Therefore, it can be concluded that the flow rate and depth of water withdrawal from the well are effective on the land subsidence and must be managed.

The phenomenon of land subsidence is one of the most important environmental hazards that have affected many plains of the country today. Jiroft Plain located in Kerman Province is also one of the areas where subsidence effects are evident. In this research, besides analyzing the spatial subsidence of Jiroft Plain and determining the extent and trend of its spread over a period of time, the effective factors in this phenomenon were investigated. For this purpose, the Sentinel-1 radar images related to the years of 2014-2022 were used. The Coherence Pixel Technique (CPT) was utilized to map the affected areas and determine the subsidence rate. The results of this method showed that the subsidence rate in Jiroft Plain had increased from 11 cm in 2014 to 13 cm in 2022. In addition, its area had increased during this period and the expansion trend had moved towards the northern areas of the plain. To analyze the causative factors of this phenomenon, in addition to studying the changes in the groundwater level of the plain and its relationship with subsidence, the roles of faults and soil thickness in creating or intensifying this phenomenon were investigated. The results showed that in addition to the uncontrolled abstraction from the aquifer, the subsidence of Jiroft Plain was affected by Sabzevaran Fault, while subsidence intensity was higher in the areas with higher soil thickness. [ABSTRACT FROM AUTHOR]

One of the dangers in many areas in recent years is subsidence. Landslides are less harmful than other hazards and its adverse consequences will directly affect human, industrial, agricultural, and civil development. The importance of paying attention to this issue is that the most harmful side effects are irreparable. Scientometric research have provided a comprehensive understanding of global research on the subject. Data were obtained from the Scopus Scientific Database (1965-2022). Most of the scientific research on land subsidence has been on the United States and China. The most important aggravating factors for the occurrence of hazards include the exploitation of groundwater and mineral extraction, which has been emphasized in most studies. On the other hand, the use of scientific technologies over the past years has become more widespread in landslide research. Now it is used more to predict the risk. Most research on the risk of land subsidence has focused on the use of methods and models, but its impacts on different aspects of human life have not been considered. The results of this research can help reduce and manage the negative consequences of land subsidence. [ABSTRACT FROM AUTHOR]

The occurrence of land subsidence phenomenon and its potential hazards in the plains of Iran due to the water crisis and drought period has grown significantly in recent years. In this study, the zoning of land subsidence hazard in the Hashtgerd plain was discussed and 19 criteria were selected as factors that influence the subsidence. The mentioned layers were prepared in GIS, weighted based on the best-worst method (BWM) and integrated using the Weighted Overlay Index (WOI). The results of BWM method showed that groundwater abstraction (0.219), the type of geological formation (0.157), the decrease of groundwater level (0.079), and groundwater depth (0.078) are important factors on the potential of subsidence hazard in the study area. Moreover, in order to evaluate the results of this model, the ROC curve was used, which has an accuracy of 90%. The results showed that land subsidence hazard of 10.66% of the study area was in very low category, 38.51% in low category, 31.49% in medium category, 11.66% in high category and 7.69% is in the very high category. According to the results, there are areas with a high probability of subsidence in the central part of Hashtgerd Plain, which requires continuous evaluation, controling, and monitoring of the criteria that affect the situation. [ABSTRACT FROM AUTHOR]

Global climate changes and population growth have increased the need to exploit underground water resources. The phenomenon of land subsidence as a result of groundwater extraction and water depletion is one of the environmental hazards that threatens societies all over the world. In this research, for the first time, Sentinel-1 radar satellite images were used by the SNAP2StaMPS to automate the process of processing and analyzing the subsidence in Marand Plain. In recent years, the uneven development of agricultural lands and the excessive extraction of underground water in the Marand plain in East Azerbaijan province have caused landslides on the surface of this plain. In this study, an automatic interferometric processing algorithm between SNAP and StaMPS was used to determine the displacement rate in the direction of the satellite line of sight. The results of the PSI interferometry technique were performed on 133 images of the Sentinel-1 satellite in the descending orbit of the Sentinel-1 satellite. Based on the obtained results, the annual land displacement rate for Marand plain in 2016, 2017, 2018, 2019, and 2020 was -13.7, -12, -2.15, -12.3 and -13.1 cm respectively. In order to validate the results, the amount of subsidence resulting from the interferometric processing was compared with the amount of groundwater level drop in the study area, using the unit hydrograph analysis method. The results showed that the amount of water level drop and the results of hydrograph analysis of observation wells in the region are consistent with the results of time series maps obtained from interferometry. Therefore, the automatic method presented in this study can be used for monitoring land subsidence. [ABSTRACT FROM AUTHOR]

One of the most important issues that has been considered by many researchers in recent years is the study of the phenomenon of land subsidence. The purpose of studying subsidence is to examine the risks and consequences that can result from it over many years. In their research, most researchers considered the occurrence of earthquakes and excessive abstraction of groundwater aquifers due to the drilling of a large number of illegal wells as the most important causes of subsidence. The aim of this study was to obtain a statistical relationship between groundwater level changes and the rate of vertical movement of the earth's surface using linear regression and grade 3 models and using InSAR radar interferometry technique in Varamin plain between 2014 and 2019. Most of the surface of Varamin plain is covered by agricultural lands and therefore it can be said that the uncontrolled abstraction of groundwater is considered as the main cause of vertical movements of the earth. In order to analyze the subsidence that occurred in this plain, Snap software was used and by applying the desired filters to eliminate the noise in the initial images, surface displacement maps were obtained in Varamin plain. The images used for the surface of the earth from 2014 to 2019 were obtained by Sentinel-1 satellite SAR sensor as ascending, and finally, by comparing the obtained statistical models from the fluctuation of the aquifer and the ground, it was found that the linear regression model has a better predictive power than the 3rd degree regression model.

Land subsidence is a vertical movement downwards of the Earth's surface. It is difficult to identify or measure because of rapidly depleting ground water. This hazard, as a hydrogeomorphology phenomenon, is revealed in many areas of the country because of the uncontrolled depletion of the groundwater. There are a number of methods for identifying and determining the rate and range of subsidence. Radar interferometry (D-INSAR) technique is known as a robust technique for land subsidence measurement. This method has superior features in terms of cost, accuracy, scale of the study area and time, in comparison with other detection methods, and can provide a precise estimation of the phenomenon. In this study, the Abarkouh plain was studied from January 2016 until February 2018. Sentinel 1 sensor images using radar interferometry technique were used to estimate subsidence. To identify the impact of groundwater extraction in land subsidence, groundwater fluctuations data from 44 piezometric wells, and also land subsidence data were analyzed using regression models. Results showed that the highest rate of groundwater depletion occurred in the town of Mehrdasht and around the agricultural fields, which led to the maximum rate of subsidence up to 12 cm/year. Ccorrelations coefficient between aquifer fluctuations and land subsidence rate is 0.79 that indicated significant relation between these parameters.

Land subsidence, as one of the most dangerous environmental phenomena, can occur for a number of reasons, including the over-extraction of the aquifer and the decline of groundwater level. Subsidence begins with vertical displacements and often causes trough, sinkhole, or deep cracks in the ground surface. The occurrence of this phenomenon in most cases causes damages that are often irreversible and costly. Therefore, for the sustainable development of the region, it is very important to accurately predict the occurrence of subsidence and controll it prior to its occurance. In recent decades, the drought and excessive extraction of groundwater resources, and as a result, the water-level decline, especially in dry and low rainfall regions, has been the main cause of this phenomenon in the plains of Iran. The aim of this study was to calculate the amount of subsidence due to the water table decline in Kashan plain. For this purpose, by collecting the required data, the groundwater has been modeled using GMS software, and based on that, the amount of subsidence during the last years has been determined. The results of this study showed that the land subsidence in the study area is increasing both in terms of quantity (from a few millimeters to several centimeters) and in terms of extent. The maximum subsidence was obtained as 5.95 cm. Therefore, it is very necessary that in addition to planned management and exact control on the exploitation of groundwater of region, academic studies, and quick actions be applied to provide the drinking and agriculture water required by other methods such as the water transfer from other areas.

Drought or instability of agricultural water resources has effects in various economic, social, political, environmental, etc. dimensions, especially in rural settlements. In this research, the relationship between the instability of water resources in the agricultural sector and rural development in the form of environmental, economic and social dimensions in the rural settlements of Rafsanjan plain has been investigated. The research method is descriptive-analytical and based on a quantitative method. Based on Cochran's formula, the number of questionnaires from 53263 rural households or small towns with the rural economies is estimated to be 380, and during the research and based on the limitations and removal of incorrect questionnaires, the number of samples reached 313. Questionnaires have been distributed in 16 rural districts. Then, the average of economic, social and environmental indicators, migration and quantity and quality of water were analyzed in SPSS software and the results were analyzed to measure significance in independent one-sample, binomial or binomial and Kolmogorov-Smirnov tests. The results of the research show that the investigated environmental indicators with an average of 3.99, economic indicators with an average of 3.88 and social indicators with an average of 4.004 on the five-point Likert scale are affected by drought. Based on this, after the occurrence of water scarcity or drought, the natural and human environment is affected and the rural development in the environmental, social and economic dimensions in the Rafsanjan Plain is disrupted and issues such as the reduction of the area under agricultural cultivation, income reduction, and land subsidence have led to poverty, unemployment, immigration and environmental consequences. [ABSTRACT FROM AUTHOR]

Introduction Today, the phenomenon of land subsidence is one of the most important geomorphological hazards on a global scale, which causes great damage to urban and rural structures, development facilities. Most of the reports from around the world related to the phenomenon of land subsidence have been related to arid and low rainfall areas. According to the US Geological Survey, a subsidence phenomenon involves a collapse or subsidence that can have a small displacement vector. Land subsidence is a geological phenomenon that causes the earth's surface to descend slowly and horizontally. In recent decades, most joints and fissures in agricultural areas have been reported due to over-abstraction of groundwater. Recently, urban areas have also been affected by this phenomenon. These seams and cracks cause a lot of annual damage to ground-level installations such as roads and bridges, buildings, power transmission lines, oil and gas transmission pipes, water pipes and sewage systems, wells wall pipes of exploitation wells. In addition, they provide a path for surface pollutants to move to groundwater sources and contaminate groundwater by infiltrating aquifers. Among the innovations of this study, for the first time, radar interferometry technique was used to investigate the risk of subsidence of Nurabad plain aquifer subsidence. , Identification of vulnerable areas in the aquifer area. Methodology The method used in this research is applied analysis. Groundwater data including piezometer and exploitation wells were used to investigate groundwater level changes and Sentinel 1 images were used to calculate radar interferometry. Geographic weighted regression model (GWR) was used to investigate the relationship between subsidence and groundwater loss parameters. By examining the changes in groundwater level of piezometer wells in the aquifer during a period of 17 years (1380-1397) showed that an average of 15 meters of groundwater drop has occurred in the plain. This decrease in agricultural and residential areas is a priority compared to other uses. By preparing the output of radar images during 4 statistical years, the results show that in 2015 the maximum amount of leakage was 7 cm and in 2016 it increased to 8 cm. In 2017 it is equal to 9 cm and in 2018 it is equal to 10 cm. In the end, by calculating the average of these four years, the amount of subsidence at the aquifer level increases significantly, with the regions in the central and eastern parts of the aquifer having the highest subsidence at the aquifer level. Which has been developed in residential and agricultural areas of the region so that the effects and evidence of these meetings are visible in residential houses and agricultural lands according to Table (2) in the analysis section to examine the status of subsidence rates in the study area using Radar images were taken during the mentioned years and show that in 2015 it is equal to 8 square kilometers, which is compared to 2014, in 2016 it is equal to 34 square kilometers, and in 2017 and 2018 it is equal to 40 and 86 square kilometers. According to the maps, we see in these 4 consecutive years that every year b The amount of subsidence at the plain level has increased and thus subsidence at the plain level has become a kind of hazard. Results and discussion High values ​​of R2 have occurred in the central parts of the model aquifer, which shows a good estimate of the model in estimating the dependent variable and the predictive explanatory variable. Also, relatively lower values ​​are located in the southern parts of the aquifer by examining the subsidence status in the plain. By creating a relationship with the groundwater drop layer, it showed that the observed values ​​with the predicted values ​​indicate a strong relationship. The layer shows the coefficient of determination R2, which is the highest coefficient of R2 in the central part, which is about -0.79 Is 0.53 Figure (7). The distribution of the remaining space of the GWR model errors shows that the model outputs are closer to the actual values. Second, the resulting map shows the low error values ​​in the range. Occlusion The average subsidence rate is about 4 cm per year and the average 4-year average is 16 cm. The average area of ​​the aquifer where the subsidence has taken place during 4 years is about 36 square kilometers, which includes about 5% of its area. The high concentration of wells and the greatest drop in groundwater and the concentration of existing cities and villages. In these areas, due to the water needs of the residential community, including the city of Nurabad and surrounding areas, as well as the water needs of the industrial sector, including factories and agricultural activities, access to water resources is more and groundwater extraction is very high. There has been a high decline that these factors with the intervention of the arid climate of this region has caused the high talent of these areas in the discussion of subsidence and has been identified as one of the critical areas of the city in the subsidence map. The results of radar interferometry show that uncontrolled extraction from the surface of underground reserves has caused the subsidence of the central part of the aquifer and also the presence of several aqueducts at the aquifer has caused damage to residential centers. One of the areas with the highest risk of subsidence in the plain, in the eastern, central and southern parts, the rate of groundwater loss in the aquifer within 14 statistical years is about 22 meters in the same well and the results of GWR method show local R2 in the central parts of the aquifer which is about 79% maximum and shows a high correlation between subsidence and groundwater loss Residual rate in the central part which is equal to 0.007 / 0007 which is a high coefficient of significance.

Land subsidence as a hydrogeomorphology event is currently occurring dangerously in many plains of the country due to uncontrolled groundwater extraction from water bearing layers, and accordingly monitoring and studying this phenomenon seems to be necessary. In this study, land subsidence rate of the Najafabad aquifer was determined through the Differential Radar Interferometry (DInSAR) processing of the ASAR and PALSAR radar data and the results were validated by comparying with the differential leveling and groundwater level drowdown data. Processing of the ASAR sensor data estimates the land subsidence in the Najafabad plain at an average annual subsidence rate of 6.7 cm and a total of 41 cm during 6 years period and processing of the PALSAR data suggests an annual rate of 7.7 cm and total subsidence of 30 cm during 4 years period. Most of the occured displacements are related to the Tiranchi, Koushk, Ghahderijan, Goldasht and Falavarjan cities. The simultaneous groundwater level data with acquisition date of the radar satellite images between 2002 and 2014 shows a drawdown ranging from 0.5 to 46.5 meters in the south and east to north of the Najafabad city consistent with the estimated land subsidence areas.The DInSAR processing of the PALSAR data has led to a more accurate results with higher spatial resolution. Results of the radar data processing can be employed for the hazard zonation directly utilized for management and planning of control and preventive measures.

The phenomenon of the subsidence of the Earth is called the downward movement of the Earth's surface, which is not easily identifiable and quantifiable due to its slow evolution. The most appropriate method is to use radar data and differential interferometry techniques. Since physical compression and pressure drop are the main causes of subsidence in the places where water is extracted, D-InSAR's integrated zoning and its simultaneous investigation with subsurface factors reflect the anomalous deformation pattern created by subsurface factors. It shows well and demonstrates that the use of D-InSAR has been helpful in subsidence navigation. For this purpose, D InSAR radar data interferometry method was applied to ENVISAT and PALSAR radar satellite data from ASAR and ALOS sensors in 2006-2008, respectively. Ambient drought moderated the effect of phase change caused by atmospheric compounds, and the lack of challenge vegetation minimized the coherence of the phase radar images and made it possible to measure changes in the C and L band radar data annually. The maximum displacement was estimated by the C band of 0.14 m and by the L band of 0.12 m. Finally, we modeled the statistical results of the groundwater of the region and the amount of subsidence estimated by the mentioned radar images by linear regression method. There is groundwater, in relation to ASAR image per meter change in groundwater level we will have 0.025 meter change in ground level elevation and PALSAR (HH) image per meter change in groundwater level, 0.021 meter change in height we will have.

Land subsidence occurs more slowly and gradually in comparison with other natural hazards, such as floods and earthquakes; therefore, it has received much less attention from human communities. However, the subsidence over time causes irreparable damage to the structure of underground aquifers, vital infrastructure such as roads, power lines, and urban structures. In this study, in order to monitor land subsidence in Chahardoli and Qorveh plains located in Hamadan and Kurdistan Provinces, the method of Permanent Scatterer (PS) was used using 59 images of Sentinel satellite in ascending passage and 58 images in descending passage. According to the average displacement of PSs in the region between Hassan Abad Emam and Ahutapeh villages of Asadabad city located in Chahardoli plain of Hamadan Province, displacement in the form of subsidence for Ahutapeh and Hassan Abad Emam villages respectively about -170 and -166 mm was happened in the time period of 2017-2018. Moreover, the research found that the subsidence in the northern part of Chahardoli plain in Hamadan Province is much more than the subsidence in the southern part of Chahardoli plain in Kurdistan Province. In order to find the cause of subsidence, the approach of examining the information of piezometric wells in the region and their changes over time was used. In this regard, it can be concluded that the land subsidence in Qorveh plain and Chahardoli plain of Hamadan and Kurdistan provinces can be attributed to the uncontrolled extraction of groundwater resources.

Over-exploitation of the groundwater resources causes many environmental hazards among which land subsidence is more important. The main aim of this study is to evaluate the effect of groundwater level drawdown on land subsidence and fissure occurrence in the Kerdi- Shirazi plain, Hormozgan Province. For this reason, the groundwater level changes and distribution of the surface and subsurface sediments in the plain were investigated. Water level data from piezometers during the last 16 years from 1999 to 2015 indicate cumulative drawdown of about 40.6 m with an average annual declining rate of about 2.2 m. The groundwater level drawdown caused considerable stress loading on the aquifer forming sediments, resulted in compaction and settlement of aquifer materials. Consequently, a large fissure with a length of about 567.6 meters appeared at the northwest part of the plain in 1394. The results of this study indicate that two main factors including groundwater level drop down and changes in the thickness of the fine-grained clay layer caused unequal subsidence, creation of the tensile stress, and consequently occurrences of the fissure. Based on these factors, hazard map of fissure occurrence due to land subsidence was prepared for the plain with three categories including the high, moderate and low hazard areas.

In this article the phenomenon of land subsidence and the resulting cracks and fissures of artificial recharge plan of Hamedan Shahid Mofateh power generation as case study has been investigated. This is an unusual phenomenon and in this research the geometrical properties of the fissures of recharge ponds are measured. The results reveal the existence of fine layers in the geology of the aquifer, which are displaced in the long run as the consequence of groundwater overdraft. Sand making of some of the water wells around study area is proof of this claim. At the site of the artificial recharge subject of this research, the difference between the quality of recharge water and the aquifer and their interaction have intensified the instability and the movement of the fine sediments. In addition, the neglect of hydraulic principles of the groundwater during the construction and operation of the recharge wells has resulted in turbulent and speed flows, intensified displacement of fine sand and ultimately the localized subsidence at the site of the plan.

Land subsidence as a hydrogeomorphology event is currently occurring dangerously in many plains of the country due to uncontrolled groundwater extraction from water bearing layers, and accordingly monitoring and studying this phenomenon seems to be necessary. In this study, land subsidence rate of the Najafabad aquifer was determined through the Differential Radar Interferometry (DInSAR) processing of the ASAR and PALSAR radar data and the results were validated by comparying with the differential leveling and groundwater level drowdown data. Processing of the ASAR sensor data estimates the land subsidence in the Najafabad plain at an average annual subsidence rate of 6.7 cm and a total of 41 cm during 6 years period and processing of the PALSAR data suggests an annual rate of 7.7 cm and total subsidence of 30 cm during 4 years period. Most of the occured displacements are related to the Tiranchi, Koushk, Ghahderijan, Goldasht and Falavarjan cities. The simultaneous groundwater level data with acquisition date of the radar satellite images between 2002 and 2014 shows a drawdown ranging from 0.5 to 46.5 meters in the south and east to north of the Najafabad city consistent with the estimated land subsidence areas.The DInSAR processing of the PALSAR data has led to a more accurate results with higher spatial resolution. Results of the radar data processing can be employed for the hazard zonation directly utilized for management and planning of control and preventive measures. [ABSTRACT FROM AUTHOR]

The Khanmirza plain is one of Iran’s fertile plains that is located in Chaharmahal Bakhtiari province. Agriculture in the area is very prosperous, but the lack of rain and over-harvesting from consumption wells has led to a reduction in groundwater levels, even causing land subsidence. Moreover, the high usage of chemical manures, especially nitrate manures, has increased the number of solutes and chemical materials in the groundwater. Thus, for this plain, making artificial ponds is important to modify the storage of the aquifer. In this study, to define the optimum locations of the artificial ponds, the effect of 12 factors was considered. The analytic hierarchy process (AHP) method was used to introduce the weight of each parameter in comparison to other factors. Afterward, the spatial priority of all factors was derived using the Geographic Information System (GIS) technique. The produced GIS layers were laid on each other and the optimum locations were obtained. Agricultural drainage was an effective index for recharge purposes. The results of the study demonstrated that groundwater level decline got the maximum weight (40%), while the land slope had the minimum weight, since the vicinity to available floodways was considered as an independent criterion. The results also showed that regions with a total area of 18 km² in north and north-west of the Khanmirza plain could be the optimum and most suitable places for artificial ponds construction. [ABSTRACT FROM AUTHOR]

The increase in the use of groundwater for agricultural and industrial development accompanied by successive droughts has greatly lowered the groundwater level. This has resulted in land subsidence. In this study, using a sample of 300 farmers, the social costs and benefits of over using of groundwater in increasing damages and repairing costs of buildings because of land subsidence in Rafsanjan city was investigated. Variance analysis and regression methods were used in this regard. The results showed that because of over drafting of ground water, increasing damages and repairing costs of buildings because of land subsidence. For elimination or reduction of ground water degradation and its effects, this paper recommended to economic evaluation in addition to the social costs and benefits. Also, the results of this study can be used as a guide for developing the city of Rafsanjan.

The increasing human need for water, on the one hand, and its scarcity, on the other, have increased the exploitation of this vital resource. Today, with more attention to groundwater resources and the vertical movement of these reservoirs to deeper layers, numerous problems are threatening life in rural habitats. The main purpose of the present study is to identify the causes of groundwater resource drawdown and its effect on the physical structure of rural areas. Crucially, it has doubled as population growth and demand increase to meet the needs of rural communities, excessive exploitation and pressure on these vital reserves. Documentary analysis and field study were used to collect the required data. The statistical population of the study included 89831 people in the rural population of Lordegan, out of which 115 were selected by purposive sampling method using the G-Power software. The data were analyzed by descriptive-analytical and causal-comparative methods on the SPSS and GIS software programs. The findings showed that increasing number of farmers, expanding irrigated areas and drilling deep wells during the period 1961-2016 are correlated with unnecessary exploitation and drop in groundwater level in the research area. The results further showed that the fragmentation of agricultural parts, granting permits for digging and breaking wells and the prevalence of aquacultural crops in interaction with population growth were the most important factors for double harvesting and reduction of groundwater levels to -22 meters in the plains. It has manifested itself in the form of the disappearance of wetlands and pastures, land subsidence of 85 cm, deep divisions in settlements and farms, changes in the appearance of plains, and, ultimately, the instability of rural settlements. [ABSTRACT FROM AUTHOR]

Various morphotectonic landforms have been created by the activity of the Dehshir Fault and the 2nd and 3rd degree Riddle faults in Plio-Pleistocene. The most important of these can be the structural depressions of Abarghoo and Taghestan along the faults derived from the Dehshir Fault in the west and smaller and numerous other depression such as Rashkouieh, Ernan, Chah Shir and Chah Torsh along the eastern faults of the Dehshir Fault. The purpose of this study was to investigate the western depressions of the Dehshir Fault in the south and southeast of Shirkouh Mountain in the south of Yazd city. The results showed that these depressions, like many other closed depressions in central Iran including Gavkhuni, have been formed due to the transtension of a stretched-separated basin. The study area was located in a cutting zone between the two active dextral faults of Dehshir-Baft and Rafsanjan-Ernan. The counterclockwise rotation of the fault block between the mentioned two faults has created local extensional zones and reduced the crustal thickness. This has uplifted the geothermal curves and partial melting and created local post-Pliocene local volcanism. Following this phenomenon, several dacitic domes have formed along the fault strike and intersection in the south and southeast of the Shirkouh Mountains and the folding of Miocene sediments. The activity of the faults, along with the rise of the domes, has led to the fragmentation of the previous smooth surface, and has caused the subsidence of some parts of the area and created several structural depressions. [ABSTRACT FROM AUTHOR]

The Hashtbandi Plain the Province of Hormozgan, is an arid and semiarid region. This plain is one of the major poles of agricultural products of the country. Which is dependent on the ground water resources. The aim of this study is to evaluate the quantity and quality of groundwater, identify and evaluate the consequences of indiscriminate exploitation of groundwater resources, and provide useful solutions in facing this problem Meteorological, hydrological, hydrogeological, and geographical data were collected and analyzed. Typical maps of groundwater chemical quality and iso-depth were prepared using the Surfer software. The drawdown of water level, reduction of storage volume and groundwater salinity changes were calculated in different areas of the plain. Qualitative and quantitative changes of groundwater aquifer are predicted for the next 10 years, using data from the past few years, assuming that the current trends of recharge and discharge of the aquifer is sustained. According to our calculations, the groundwater level has been consistently decreasing during the past years. The groundwater level has dropped 5.64 meters over a period of 11 years (2003–2014), with an annual average of 0.5 meter. The annual discharge of groundwater through wells is 40.09 Mm3, while the annual recharge was 38.89 Mm3, and therefore reduction of the storage volume has been 1.2 Mm3, per year. Results of this study showed that excessive exploitation of groundwater resources, followed by a series of problems such as changes in groundwater quality, increasing vulnerability to drought, land subsidence, change in the ecosystems and drying of fruit orchards. If the exploitation of groundwater resources continue at the current level in the study area, it is predicted that the groundwater levels will drop more than 8.4 meters over the next 10 years on average (until 2024). The amount of drop in groundwater level will reach more than 12 meters in the central part of plain, and this can cause social and economic and environmental crises in the region. Control of groundwater withdrawal, water pricing in agriculture, providing an optimal pattern with the soil and climatic conditions in the region, express problems and raise the level of knowledge of the beneficiaries are some of the management strategies, which have to be implemented if the water crisis is to be prevented.

One of the main reasons of regional subsidence is drawdown of groundwater level due to Overexploitation of aquifers which can lead to irrecoverable damage to soil deposits. The regional subsidence that has been inflicting Iran in recent years, have greatly damaged to agricultural sites, residential buildings, roads, power transmission lines, etc. The Damaneh City, located at west of Isfahan Province, has been affected by this phenomenon extensively. Therefore, the present study aims to investigate the level of depletion of groundwater resources and subsequently land subsidence in this region. The results indicate that drawdown of groundwater level had a direct influence on the subsidence occurrence in the studied region. Considering that the studied area is one of the most important Isfahan's agricultural regions, the primary exploitation of aquifers is related to agricultural purposes. The results showed that water table has dropped 20 m in the Damaneh city during 1977-2014. Accord-ingly, it is essential to use artificial recharge and changing cultivation pattern to revive aquifer and also prevent damage induced by land subsidence.

Groundwater overdraft is one of the main reasons of land subsidence. Differential subsidence leads to earth fissures and damages to structures, roads, railroads, pipelines, irrigation canals, and sewage networks. In order to simulate land subsidence due to groundwater overdraft, a fully coupled finite element consolidation model was developed. Formulation of finite element was based on Biot three-dimensional consolidation theory. Land subsidence studies inRafsanjanCitywere conducted by collecting and analyzing data on geology, geophysics, hydrology, soil properties, and observed land subsidence. Due to lack of sufficient experimental data about different soil profiles, land subsidence monitoring and back calculation were used in several spots to obtain the necessary data for use in other places. A computer model was finally developed to predict the subsidence of the city and its effects on the sewage network were studied.