subsidence

In arid and semi-arid regions, groundwater is more important for humans and ecosystems than surface water. Land subsidence is caused by the pumping and uncontrolled use of groundwater in an area. When the extracted quantities are not replenished by rainfall, it leads to damages such as road failures, destruction of residential areas, railways, as well as water and gas pipelines. The Yazd-Ardakan plain is one of the main plains in Yazd province, hosting 75% of the province's population density and most industrial centers. Additionally, this plain has been subjected to a ban by the Ministry of Energy due to a sharp decline in groundwater levels. This study aimed to quantify and compare the extent of subsidence using four Synthetic Aperture Radar (SAR) images of the C-band from the Sentinel-1 satellite and the radar differential interferometry method from 2017 to 2021. The maximum subsidence recorded in 2017 was 13 cm, while in 2020 and 2021, it decreased to 9 cm, primarily concentrated in the Shamsi region between Meybod and Ardakan. Furthermore, to validate the satellite-derived results, they were compared with those obtained through accurate leveling methods conducted by the Iran National Cartographic Center. The study revealed that Sentinel images exhibit a strong capability to estimate the extent of subsidence. Considering the examination of groundwater consumption and depletion statistics in recent years, potential reasons for the reduction in subsidence in the study area could be attributed to management measures such as water transfer to this basin, alterations in agricultural practices, and a decrease in groundwater depletion compared to previous years in this region.

Land subsidence is one of the environmental hazards that humanity has faced in recent decades due to excessive extraction of groundwater resources in alluvial areas. This phenomenon, like other hazards (earthquakes, droughts, floods, storms, landslides, etc.), is considered an obstacle to socio-economic and civil development. The Neyshabur Plain is one of the most important plains in Khorasan Razavi Province in terms of agriculture and population density, which is located in the northeast of Iran with an arid and semi-arid climate. In this study, Sentinel 1A satellite images were used in a 5-year period (2017 to 2022) to monitor the rate of subsidence within the city of Neyshabur. The main objective of the present study is to investigate the effects of land subsidence awareness on responsible tourism within the city of Neyshabur. The results of radar interferometry studies showed that 18 cm of subsidence occurred in the study area during a 5-year period. Data from piezometric wells in the area were used to determine the cause of land subsidence, and their changes were examined during the period 1370-1398. The registered subsidence rates for each period were 4 cm for 2017-2018 (1395-1396), about 6 cm for the period 2018-2019 (1396-1397), 5 cm for the period 2019-2020 (1397-1398), 2 cm for the period 2020-2021 (1398-1399), and 1 cm for the period 2021-2022 (1399-1400). The results of the study showed that there is a close relationship between the decline in groundwater levels and areas with land subsidence in the city of Neyshabur, which has affected responsible tourism. Especially in the northern part of the city, which has the highest groundwater level decline of 36.78 meters and is also in a high subsidence risk zone. According to the analysis of the results obtained in SPSS and Smart Pls software, all factor loading scores were higher than 0.5, Cronbach's alpha for both main values ​​was confirmed and more than 0.7, and the AVE coefficients were also obtained more than 0.5, and validity and reliability were confirmed. Finally, the effect of awareness of subsidence on responsible tourism was confirmed, indicating that awareness of Neyshabur subsidence, as an environmental challenge, has affected tourists' tourism decisions.

Land subsidence refers to the gradual or sudden lowering of the earth's surface as a result of various factors such as tectonic activities, mining, oil and gas fields, and illegal extraction of underground water. In Alborz province, the growing trend of population and migration in recent years has added to the increase in demand and the amount of water withdrawal from the underground water table, so it is subject to subsidence due to the sharp drop in the level of underground water. In this research, subsidence was first evaluated using the radar interferometric technique, and then, prone areas were zoned with a multi-criteria algorithm in the time frame of 2016 and 2023. The results of information extraction with interferometric technique showed that the average amount of subsidence in the urban boundaries of Saujblag, Karaj, Nazarabad, Chaharbagh and Fardis is between 15 and 320 mm. According to observations, the highest amount of subsidence is in the eastern part and then in the southern and southwestern parts. According to the estimated results of subsidence risk zoning; The parameters of water level drop, land use, slope and geology, respectively, with weight coefficients of 0.16127, 0.141875, 0.130145 and 0.128474, are the most important factors in creating the risk of subsidence in the study area, which are 31 and 23%, respectively. From the range, it has a very high and high probability of danger. Finally, it can be said that the most important factor in subsidence in the studied area is excessive use of underground water and the drop in water level. In some urban areas, such as Hew and Goch Hesar, Malekabad-Mehrshahr-Mehrvila-Kamalshahr, and Mohammadshahr, the highest risk of subsidence can be seen.

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.

 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

Subsidence is an environmental phenomenon caused by the gradual subsidence or sudden subsidence of the earthchr('39')s surface. The phenomenon of subsidence in residential, industrial and agricultural areas can cause catastrophic damage. In most parts of Iran, there is a high correlation between land subsidence and the decrease of groundwater level and consequently the density of soil layers. In this study, using two time series of radar images with artificial apertures from Sentinel sensors belonging to 2014 and 2019, the amount of subsidence in Damaneh plain (Frieden city) was calculated. Wells were studied in the period 2014 to 2019, the results of the study of the correlation between land subsidence with changes in groundwater level at the level of 95% was significant. In the continuation of the research, using the logistic regression model, the subsidence trend in the study area was predicted and a subsidence probability map was prepared and created as a dependent variable for the logistic regression model. The independent variables used included altitude, slope, slope direction, geology, distance from the road, distance from the river, land use, distance from the village, groundwater level, piezometric wells. The output of the model is subsidence risk zoning map which was created in five classes. The accuracy and validation of the logistic regression model was evaluated using the system performance characteristic curve and the accuracy (0.89) was obtained. The good accuracy of the logistic regression model in producing the probability map Subsidence is in the study area. In the output of the model, it was found that the area of ​​1980 hectares, equivalent to 7.9%, has a very severe subsidence that has put the situation in a dangerous situation and the need for control and management to reduce this destructive effect.

Land subsidence is one of the environmental hazards that threatens most countries today, including the majority of Iran's plains (Ranjabr and Jafari, 2010). Damages caused by subsidence can be direct or indirect. Infrastructural effects are direct and indirect effects of subsidence, but economic, social and environmental effects are indirect effects of subsidence (Bucx, et al., 2015). The environmental effects of subsidence are related to other effects of subsidence, including the infrastructural, economic and social effects of subsidence. The southwest plain of Tehran is considered one of the most important plains of Iran due to its large areas of residential, agricultural and industrial lands from various aspects, especially economic, political and social. The subsidence of the Tehran plain was first noticed by the measurements of the country's mapping organization in the 1370s. Since 2004, the responsibility of investigating this phenomenon in the plains of Tehran was entrusted to the Organization of Geology and Mineral Explorations of the country. Although several researches have been done in the field of subsidence factors, amount and zoning. In the field of estimation of subsidence and changes in water level, spatial correlation of subsidence with changes in water level and estimation of vulnerability due to subsidence according to the density of population, settlements and facilities in the southwestern plain of Tehran has not been done.

In the current research, we will analyze and estimate the spatial regression of the subsidence phenomenon by InSAR technique with water level changes from 2005 to 2017, as well as the environmental effects of subsidence in the southwest plain of Tehran by using Quadratic analysis method (O’Sullivan and Unwin, 2010). The criteria map of the current research is overlapped using the ANP method (Ahmedabadi and Ghasemi, 2015) weighting and finally with the SAW method (Emaduddin et al., 2014) in the Arc GIS 10.8 software, and the vulnerability map due to land subsidence in the study area is prepared.

The average subsidence in 12 years is about 9.9 cm per year. Average subsidence has occurred in four main zones. Maximum and minimum subsidence have been observed in B (near the Sabashahr) and D (in east of plain) zones respectively. The results of the interpolation of the depth of the underground water in the study area indicate that the general trend of increasing the depth from the south (10 meter) to the north (more than 90 meter) of the plain. The results of spatial correlation showed that there is a significant direct relationship between the spatial layer of the average subsidence rate of Tehran Plain and the spatial data of the underground water level, and the R value is equal to 0.61. The distribution map of the underground water depth of the study area in the form of Quadrat analysis shows that in the main part of the plain, the depth of underground water is at an average level. The general trend of changes in the level of underground water is decreasing from northwest to southeast and is in 5 levels. The distribution of the networks shows that the rivers have three linear trends from north and northwest to south; their dispersion is mostly in the center of the study area. The flood rate is higher in the central plain networks. In study area, there are important arterial roads such as Tehran-Qom highway, Tehran-Saveh highway and Tehran Azadegan highway. The southern and northeastern areas of the study area are urban settlements such as Islamshahr, the 18th and 19th districts of Tehran Municipality and other residential areas such as Sabashahr. The major part of the region has fertile soil and the occurrence of subsidence can have negative effects on the fertility and texture of the soil in the study area. The results of vulnerability analysis due to subsidence show that there are 5 vulnerability classes in the study area including very low, low, medium, high and very high.

All in all most of the study areas (central, northern and western networks) are in medium, high and very high vulnerability. About 14,600 hectares of the study area are in medium vulnerability. Which is continuous from the west to the east of the study area. Most of the urban infrastructures are moderately vulnerable to subsidence. About 17,000 hectares of the southwestern plain of Tehran are very vulnerable. That more than half of the area of ​​this area is covered by settlements and urban infrastructures. Therefore, the phenomenon of subsidence causes irreparable damage to the settlements and infrastructures in the southwest plain.

The subsidence phenomenon is considered one of the most frequent hazards occurring worldwide and imposing irreparable damages every year. This phenomenon affects the ground’s surface and its layers and causes the ground deformation. It can be referred to as a morphological phenomenon that is associated with the gradual sinking of the ground and the vertical movement of materials. Among the various methods used to study the land subsidence pattern, the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique has provided more accurate results. Therefore, this technique was used to investigate the subsidence rate in Mashhad plain from 2003 to 2010 and the Envisat ASAR (C-band) and Sentinel-1 ASAR (C-band) satellite images were employed during the year 2019. The results show that the highest subsidence rate of about 44 cm occurred in Qasem Abad and Kalateh-ye Barfi lands from 2008 to 2010. A subsidence rate of about 37 cm was also observed in the same area from 2007 to 2009. The interpolation results using piezometer well statistics show a decrease in groundwater levels in this area and confirm the accuracy of the results.

The landscape of the earth's surface as a complex system is the result of the interaction of factors such as geographical, climatic, temporal processes and human activities. The physical development of cities, without observing the principles of urban planning and taking into account the potential of their natural hazards, leads to the high vulnerability of cities. One of the most important dangers in the plains and plains of our country is the dangers caused by land subsidence, which for various reasons, such as over-harvesting of underground water resources and climate changes, causes many problems for agricultural lands, roads, and transmission lines. has become power and energy; Therefore, it is very necessary to investigate the causes and to control and reduce its risks (Abedini et al., 1402). Groundwater is one of the most important sources of water needed by the agricultural, drinking and industrial sectors, especially in the dry areas of the central plateau of Iran. Therefore, investigating the process of its qualitative changes is very important in the sustainable management of water resources (Arshad Hosseini et al., 1400). . Yilaghi city of Shandiz, which is a part of Targaba Shandiz city, is 1400 meters above sea level and is located at 59 degrees and 17 minutes of latitude and 36 degrees and 23 minutes of latitude. This city is adjacent to the central part of Mashhad from the north, Targaba city from the south, Neishabur from the east and Golbahar from the west, and has an area of about 37,825 square kilometers. Since Shandiz Mashhad is known as one of the holiday areas of Khorasan and is surrounded by thick and dense vegetation of towering sycamore trees and flowing rivers and tourist attractions (Karizno Aqueduct, Shandiz Historical Tower, Shandiz Padideh, Cozy Cottage Garden, Panjan Nama, Park It is mountainous and...), has a cool and summery climate and is one of the main centers of travelers and tourists in Mashhad and all over Iran. All over the south of this city are the heights of the Binalud mountain range of Khorasan, and Shirbad peak in the Zashk region of Shandiz is also considered the highest point of this mountain range and Khorasan province.

In order to investigate the subsidence rate of Shandiz city and its relationship with the drop in the underground water level, first the rate of land subsidence in the period of 2016-2023 was calculated annually by radar interferometric method and then the trend of changes in the water level of piezometric wells during 29 years was investigated. took Finally, the research results were verified by field surveys. In order to process by radar interferometric method, SNAP software was selected to obtain the final results of the subsidence rate based on the phase difference between the images taken on different dates. In order to study the latest status of the groundwater level in the study area, the statistical information of piezometric wells from 1370 to 1399 was obtained from Razavi Khorasan regional water, which was then prepared in the GIS software after annual averaging using the IDW interpolation model to prepare the groundwater level map. and was evaluated.

In the investigations carried out with SLC radar images of Sentil 1 satellite in relation to the city of Shandiz, 8 images were processed two by two in the Snap software, the image of the year 2016 with 2017, 2017 with 2018, 2018 with 2019, 2019 with 2020 and 2020-2021, 2021-2022 and 2022-2023 images were checked and the amount of subsidence recorded for each period was 2 cm for 2016-2017, 6 cm for 2017-2018, 2 cm for 2018-2019, 5 cm for 2019-2020, for The 2020-2021 period was about 2 cm, 4 cm for the 2021-2022 period and about 1 cm for the 2022-2023 period. In the survey of the water level of Shandiz city from 1370 to 1399, the number of 2 main wells, Hassan Abad and Qasim Abad, which are located in the northeast and east of the city at a distance from it, were obtained with the same data, which information was obtained from the Khorasan Razavi Regional Water Organization. and was investigated. The data were averaged every 5 years and its maps were prepared using the IDW tool in the GIS environment for the study area. In the east of the region, the villages of Hesarsokh and Sarassiab were located in the area of high risk. The minimum and maximum water level drop in the 30-year period from 1370 to 1399 was calculated as 57.86 and 76.84 meters.

The results of interferometric studies showed that the amount of subsidence during 5 statistical periods in the studied area was 22 cm. The amount of subsidence recorded for each period is 2 cm for 2016-2017, 6 cm for 2017-2018, 2 cm for 2018-2019, 5 cm for 2019-2020, and 2 cm for 2020-2021. 4 cm for the 2021-2022 period and about 1 cm for the 2022-2023 period. According to the obtained results, the highest amount of subsidence has happened in the east, north and south of Shandiz from east to west. The water levels of the wells have reached their maximum decrease in the period from 1370 to 1399. The water level drop in this time period is at least 57.86 meters and the maximum is 76.84 meters, and all areas of Shandiz city have water level drops and are at risk. The subsidence has also covered most of the city areas. Shandiz city is a tourist area and all its geosites (Carizno Aqueduct, Shandiz Historical Tower, Shandiz Phenomenon, Cozy Cottage Garden, Finjan Nama, Mountain Park, etc.) are vulnerable to damage, therefore it needs special attention.

Land subsidence is a geological hazard that occurs in connection with human activities and environmental changes. This hazard has occurred in 60 countries and more than 150 cities of the world. Similar to many regions of Iran, the southern plains of the Alborz mountain range are facing rapid land subsidence in connection with excessive extraction of groundwater. Considering the average water consumption and the scattered data related to the drop in the underground water level in the country, it is not difficult to recognize that subsidence and its consequences have become a problematic phenomenon in the country. In recent years, many cracks have appeared in agricultural lands and residential buildings, streets and infrastructures of the study area; In such a way that in the agricultural sector of the region, it has caused the destruction and destruction of part of the lands, and in the residential sector, it has caused successive settlements in the buildings and caused irreparable damages.

In this research, data analysis was done in several stages, which are described below. In the first stage, using the information related to the water level drop of the wells in the studied basin, the amount of changes in the water level of the wells was calculated and then a map of the groundwater level drop in the studied basin was prepared. In the second step, using Sentinel 1 images for a period of 5 years (January 2017 to January 2022) and using the SBAS time series method, the amount of subsidence of the studied basin has been calculated. At this stage, the desired images with 24-day intervals have been prepared. After preparing the images, Linux operating system and SNAP software have been used to process the images. In the next step, the correlation between the amount of subsidence with the state of groundwater level drop in the region and other geomorphological parameters has been evaluated, for this purpose, the interpolation map related to the drop in the groundwater level of the region was entered into SPSS software in pixel format and then the subsidence map was also created. In the same way, it was entered into the SPSS software, and in this way, the relationship between the amount of subsidence and the groundwater loss of each pixel was evaluated together. At this stage, using the integrated model of fuzzy logic and AHP, areas prone to subsidence have been identified. To do this, first, the desired parameters including lithology, height, slope, the amount of groundwater loss, proximity to the river and topographic units have been selected. After preparing the desired information layers, the layers are scaled based on the subsidence potential. After fuzzy membership of the layers, the layers are weighted based on the opinions of experts (3 Geomorphologists) and the Analytical Hierarchy Model (AHP) and finally, the layers of information are combined using the fuzzy gamma operator and the final map of the areas prone to subsidence is prepared.

The area of Hashtgerd Plain lacks the variety of geomorphological landforms and is mainly located on the plain and old conifers. The absence of geomorphological barriers has made the residential and agricultural development in this area not to face much restrictions. Therefore, in the period of 30 years, there have been major changes in the land use of the region. The land use map of the studied area during the years 1990 to 2020 shows the increase of residential and agricultural uses. According to the results of calculating the water level drop in the studied wells, in this research, using the spline interpolation method, an annual groundwater drop map has been prepared in the study area, based on this, the middle and southern areas of the range Studies have the highest average annual groundwater level drop.
The correlation between the annual average drop of the underground water level and the amount of subsidence has been evaluated, and the results show that the correlation coefficient between them is about 7%. According to the results, it can be concluded that the Hashtgerd range has experienced subsidence between 18 and 320 mm in our five-year period.

Land subsidence will ultimately be the "death of the aquifer" and the destruction of agriculture and horticulture in the Hashtgerd Plain. With the continuation of this process, the fertile lands of Hashtgerd region will face a dark prospect and irreparable social and economic effects will affect the region. The results of radar interferometry indicate that the amount of subsidence in the study area during a 5-year period is between 18 and 32 cm. The final subsidence map shows that the highest amount of subsidence is in the southern and western areas and the lowest amount is related to the northern areas of the study area. Based on the assessment of areas prone to subsidence risk, it can be seen that the results of radar interferometry are highly reliable to a significant extent.

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.

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.

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.

The phenomenon of land subsidence can cause irreparable financial and human losses and damage many surface and subsurface structures in urban areas and their suburbs. According to the definition of the Geological Institute of the United States of America, the phenomenon of land subsidence includes the collapse or downward settlement of the earth's surface, which can have a small displacement vector, it is said to occur gradually and instantaneously on a large scale. The most important cause of the regional subsidence of the earth's surface in the sedimentary basins of arid and semi-arid regions is the condensation and compaction of sediments due to excessive extraction of groundwater sources. If watery clay layers are placed between sand layers, this phenomenon will be observed more widely and more acutely. Land subsidence usually occurs with a time delay after the long-term extraction of underground water resources. The amount of subsidence depends on the thickness and compressibility of layers, length of loading time, degree, and type of applied stress. With the decrease of the underground water level, the increase of the effective stress caused by the decrease of the pore water pressure causes subsidence. Usually, it takes time to reduce the water pressure and increase the effective tension; Therefore, following the reduction of the piezometric level, subsidence will occur with a time delay. Subsidence caused by the drop in fluid level mainly takes place in unconsolidated or semi-consolidated sediments that are located in the vicinity of sand layers. In such conditions, inelastic compaction occurs due to the increase of effective stress in the soil, the arrangement of the soil grains is disturbed and the thickness of the vertical layer decreases. In the areas where the sediments are not very thick and the underground water extraction continues indiscriminately, lines and cracks are observed on the surface of the land, especially agricultural land, and it is known as the Shaq phenomenon. The phenomenon of subsidence due to the withdrawal of underground water can have different intensities and destructive effects according to the geological situation and geotechnical characteristics of the region. In the sedimentary basins of arid and semi-arid regions, including the Mashhad Plain, the most important cause of ground subsidence is the density of underground water tables due to excessive water extraction. This situation is especially critical in the area where excessive pumping of aquifers containing sand layers is located between impermeable clay layers and causes subsidence. This phenomenon is also happening in Iran, and it is visible, especially in the eastern and central regions of the country, which suffer from drought and the water supply through underground water extraction has greatly increased. Mashhad Plain is one of the areas with a very high subsidence rate, which needs to be given more attention. Land subsidence is a dangerous global problem, and geometric methods are not suitable for extensive and serious monitoring of land deformation.

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 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 Mashhad is monitored and measured.In the present study, using radar interferometry and SBAS time series method, in the period from 2014 to 2021 in Mashhad city, by selecting 38 Sentinel-1 images with a suitable time interval, the average speed of land subsidence and uplift in the studied area was estimated.Then, to determine the main factors of this event, the studied area was investigated in terms of changes in the underground water level and tectonics.

The results of the analysis of the time series of the images showed that in Mashhad, the maximum ground displacement is between -77 and +8 mm, and the areas with subsidence are located in the northern parts of Mashhad, which is recorded between 30 and 30 mm. 77 mm subsidence per year. To determine the cause of this event, tectonic assessment and the status of underground water exploitation in this period and its relationship with land subsidence and earthquake data in the area were investigated.

The results of the research showed that the maximum subsidence rate is 77 mm in the area of Mashhad in the period of 7 years from 2014 to 2021 and is related to the north of Mashhad. It should be noted that while advancing towards the city center from the north, you should look for irreparable damage shortly. To check the accuracy of interferometry and interpret the results and investigate the possible cause of the subsidence of Mashhad city, the trend of changes in the water level in piezometric wells, this factor in the occurrence of subsidence in the region was investigated. The information on piezometric wells was obtained in the city of Mashhad, the results of which strongly showed the water level in the past years, which is based on the cause of subsidence in this area. Only in the center is the temporary rise of the underground water level due to the feeding of the urban Mashhad aquifer.Then, to investigate the tectonic participation in the subsidence event, the history of earthquakes and the fault network of the region were evaluated, which confirmed the absence of the investigated earthquakes (maximum 3.8 on the Richter scale) in the region and its surroundings, and there is no fault network within the area of the subsidence assets. did not have. There is no activity. The probability of supposition and the possibility of technology playing a role in the subsidence event is insignificant. Small cracks are mainly created near mental wells or agricultural water exploitation wells and are scattered much more.

Khanmirza plain is one of the plains of cold and temperate regions of Iran, with an average rainfall of 500 mm per year and sufficient nutrition in terms of surface resources, the subsidence event is currently happening in it with a rapid trend. In terms of geostructure, Khanmirza plain is located in the folded Zagros zone in the south of the Dana fault, and the presence of piezometers protruding from the soil, as well as the presence of springs, etc., are signs of crustal movement on the surface of this plain. For this purpose, with the aim of evaluating the tectonic activity of the region in creating the phenomenon of subsidence from some geomorphic indices such as basin shape index (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), reverse topography symmetry index (T), integral index Hypsometry (H) of the region's subsidence was studied tectonically. Likewise, the subsidence rate was determined using radar interferometry. Examining these indicators showed that the indicators of basin shape (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), reverse topography symmetry index (T) are active tectonics in the region. Earth construction activities have caused the plain to stretch and become asymmetric on both sides of the main river. Likewise, the results of radar interferometry in the two-year period indicate that parallel to subsidence (at a rate of 9 cm) in some parts of the plain, other parts are facing uplift (at a rate of 21 cm).Collapse and subsidence can be caused by natural geological phenomena such as earthquakes, dissolution of limestone, chalk and salt rocks, melting of ice and compaction of deposits, slow movements of the crust and the release of lava from the solid crust of the earth, or activities human activities such as mining, extracting underground fluids such as underground water, oil or gas (Galloy and Barbie, 2011: 1459). Radar interferometry has been widely used by Earth researchers since the early 1990s (Shirani et al.: 2013). This technique can be used to measure displacements resulting from many phenomena such as earthquakes, landslides and subsidence. In general, there are nearly six hundred plains in Iran, and it is likely that more than half of them are subject to subsidence (Kia Sharifi, 2010: 58).

In order to evaluate the tectonic situation of the region, from topographic maps 1:50000 and geological map 1:100000 to calculate basin shape index (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), symmetry index Inverted topography (T), hypsometric integral index (H) from (DEM) 30 meters and topographic map were used, which were processed in GIS environment. D-InSAR radar images were used in the period from 2003 to 2005, which were processed in ENVI 5.3 software. Radar interferometry technique

How to calculate the SL river gradient index: The SL index is calculated for the middle point between two flow curves. Symmetry index of transverse topography (T): this index can also specify the state of symmetry and, as a result, the active or inactive state of the region. Drainage basin asymmetry index (AF): The asymmetry index is a method to evaluate the existence of tilts caused by tectonic activities at the scale of the drainage basin. Basin Shape Ratio Index (BS): Basins that have an elongated shape are tectonically active. And the shape of basins that are tectonically inactive tends to be round. Integral Hypsometric Index: Integral Hypsometric is an index that calculates the height of the entire area in relation to the area of the entire area. The values of this index show the transformation stages of the landscape in the erosion cycle. Today, radar interferometry, as a technique that estimates the displacement of the earth's surface with high accuracy and resolution, is a common tool for investigating the change of the earth's surface due to various factors, including land subsidence. In this technique, an interferogram can be prepared using two satellite images. So that by using the interferometric tool, the phases of the return signal from the ground are subtracted from each other in two time-delayed satellite images of the same region to extract changes in the ground surface. The radar interferometry technique uses Sarscape software as one of the powerful tools in the digitization of satellite images to survey the changes in the earth's surface. In this research, 12 Envisat satellite images from the European Space Agency were prepared

 The amount of subsidence calculated from 10 paired images is 9 cm drop in a two-year period, and the amount of elevation obtained from the images was calculated as 21 cm in a two-year period. By comparing these two numbers, it can be concluded that in this basin, the uplift rate is twice as high as the subsidence rate.The obtained values show that in addition to groundwater extraction as one of the main and common causes of subsidence, considering the tectonic factor in areas such as the Khanmirza watershed with high rainfall input is one of the main reasons for its formation.

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.

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.

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.

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.

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.

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.

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.

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.

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

Subsidence risk, unlike many risks such as floods and earthquakes, is insignificant and in the long run causes a lot of damage such as cracking of buildings, sloping of high facilities, destruction of agricultural lands, subsidence, etc. So the areas at risk are facing a lot of challenges. Among the areas that are at risk of subsidence are the plains of arid and semi-arid regions, including the plains of Iran. In fact, the location of a large part of Iran in the arid and semi-arid region has caused these areas to face a shortage of surface water resources, and this has led to overuse of groundwater resources in recent years and the occurrence of the risk has subsided. One of the areas that is at risk of subsidence is Kaboudar Ahang-Famenin plain in Hamadan province. Due to the lack of limiting geomorphological barriers, this plain has been associated with the development of many agricultural lands and due to the lack of sufficient surface water resources, the utilization of groundwater resources in this plain has been more than allowed and this has caused a decline. Extreme groundwater resources in this area and eventually the risk of subsidence. Due to the importance of the issue, in this study, the subsidence of Kaboudar Ahang-Famenin plain has been evaluated and the effective factors in its occurrence have been analyzed.

In this study, in accordance with the subject and objectives, statistical information (information about 13 piezometric wells in the study area), library and video (radar images related to Sentinel 1 satellite, Landsat satellite images and also 30 m high digital model SRTM) has been used as research data. The tools used in the research include GMT software (to prepare subsidence mapping using radar interference and Russian SBAS time series method), Google Earth (to monitor area and identify subsidence) and ArcGIS (to prepare final maps). According to the objectives, this research has been done in three stages. In the first stage, using the digital model of 30 m altitude SRTM and Landsat satellite images, the geomorphological status and land use of the region have been studied. In the second stage, in the second stage, using information related to 13 piezometric wells, the groundwater depletion situation of the region was investigated and in the third stage, using Sentinel 1 radar images and SBAS time series method, the amount was evaluated. Subsidence of Kaboudar Ahang-Famenin plain has been studied.

The study of the altitude situation of the region shows that there is a very small difference in height between the cities of Kaboudar Ahang and Famenin and also there are no significant obstacles and landforms in this distance. Also, the study of the slope classes of the region shows that the area of Kaboudar Ahang-Famenin plain is less than 10% in the slope class and the region does not have steep and restrictive areas. According to the prepared maps, Kaboudar Ahang-Famenin plain, in terms of geomorphology, has no limiting obstacles for the development of agricultural lands as well as residential areas. In fact, the lack of restrictive barriers has led to the development of agricultural lands in this region, especially irrigated agricultural lands in recent years, and this has led to excessive pressure on groundwater resources in recent years. The results of the study of the decline in groundwater resources in the region indicate that the rate of decline in water levels during a period of 24 years has been between 14.7 (Hemehkasi well) to 78.1 (Einabad well) meters. Also, according to the calculations, most of the studied wells have faced an average of more than 2 meters of water level drop annually. Also, the results of the assessment of subsidence in the region indicate that the study area has had a subsidence of 29 to 216 mm during a period of 5 years (from 16/01/2015 to 14/01/2020).

The results of studying the natural state of Kaboudar Ahang-Famenin plain have shown that this plain has a high subsidence potential due to its geomorphological and hydro-climatic conditions. In fact, in terms of geomorphological status, this plain is without limiting obstacles for the development of agricultural lands, and this issue has led to the development of irrigated agricultural lands regardless of environmental capabilities, including the hydro-climatic situation of the region. According to the above cases, the development of agricultural lands, regardless of the capacity of water resources in the region, has led to over-harvesting of groundwater resources and as a result, a sharp drop in groundwater levels Based on the results of the evaluation of 13 wells studied, most of the studied wells, with an average annual water level drop of more than 2 meters and this issue has caused the Kaboudar Ahang-Famenin plain during The 5-year period (from 16/01/2015 to 14/01/2020) should have a subsidence of 29 to 216 mm. Also, the results of the study of the spatial distribution of subsidence have shown that the highest amount of subsidence is related to the middle areas of the region and the distance between Kaboudar Ahang and Famenin cities, and considering that in these areas there was the highest level of groundwater loss, Therefore, it can be said that the main cause of subsidence in the region has been a sharp decline in groundwater resources. The sum of the results of this study has shown that Kaboudar Ahang-Famenin plain is in danger of subsidence and this issue has led to the emergence of numerous depressions in this plain which is a serious threat to human facilities and habitat.