mojtaba yamani

In this study, the Permanent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) technique was applied to Sentinel-1 imagery acquired in 2022 in order to assess the impacts of land subsidence on urban structures in the southwestern part of Tehran. For this purpose, the GMTSAR and StaMPS software environments were employed. In addition, using groundwater level measurements from observation wells within the study area, the standardized cumulative groundwater level variations were calculated. The interferometric processing results indicate displacement rates ranging from +3 to −95 mm per year along the satellite line of sight across the southwestern of Tehran. The maximum subsidence is associated with the southern part of district 18 and the western part of district 19, with an annual rate of approximately −70 mm. The vertical displacement and lowering of bridge decks caused by subsidence were estimated to range between 2.3 and 4.5 cm per year. Field inspections of the studied bridges reveal that at bridge No. 3 (the intersection of Kazemi expressway and Shokoofeh boulevard), the manifestations of ground subsidence are clearly evident. The results of the correlation analysis between groundwater level fluctuations and the elevation changes recorded by bridge selected permanent scatterers demonstrate a strong relationship between the two variables. This high correlation indicates that, in addition to the downward motion associated with regional subsidence, hydrological saturation of the soil contributes to localized elevation changes affecting both the ground surface and human-made structures.

Groundwater is the main source of water and one of the most important sources of fresh water on Earth. The quantity and quality of groundwater are deteriorating due to increasing urbanization and its side effects (Amanpour et al., 2021). Recently, with rapid population growth, urbanization and industrialization, groundwater resources have been at risk and have created a serious environmental problem (Afsaw et al., 1, 2020). Therefore, human activities in some cases damage the balances of capacity in nature. One of the most important water resources vulnerable to pollution is aquifers. These resources are exposed to pollution in various ways, which makes detecting and controlling pollution in them more difficult and costly than surface waters. Also, due to the persistence of pollution in these resources, the best way to prevent their pollution is to identify polluting sources and vulnerable areas, prepare vulnerability zoning maps, and adopt appropriate management policies (Aghdam et al., 2017). Identification and preparing zoning maps of vulnerable areas of the aquifer is an appropriate management tool to prevent pollution of underground water resources. Considering the importance of Khovayes Plain in agriculture water supply, drinking and industrial conditions, the drastic model is used to assess the aquifer vulnerability. In the drastic model, some significant indices in the assessment of underground water aquifer vulnerability including water table depth, water supply network, aquifer type, soil type, topographic dip, components of  the unsaturated zone , and hydraulic conductivity were used and prepared as seven layers in ArcGIS software; after weighting, ranking and integrating the seven mentioned layers, considering the pollutions, the final map of vulnerability aquifer was prepared. After matching the Nitrate Ion on the final drastic map, it was found out that all points with a high amount of Nitrate, are located in a highly polluted realm which confirms the accuracy and validity of the used model.

The vulnerability zoning of the Dasht-e Khosh aquifer, which was obtained by combining the seven raster maps of the parameters of the DRAS-1 model by considering the weight of each parameter in the Geographic Information System (GIS) environment, shows that in the Dasht-e Khosh region, the parameters of groundwater depth and unsaturated environment have the greatest effect and the parameters of land slope have the least impact in determining the level of vulnerability of the aquifer. Nitrate ion a natural pollutant in the region) was used to verify the final vulnerability map. By matching nitrate ions on the final DRAS-1 map, it was determined that all points with high nitrate ions are located in an area with high pollution force, which can confirm the accuracy and precision of the model. In terms of area, it can be said that about 17.16% of the study area is in the very low vulnerability range, 23.55% is low vulnerability, 19.21% is medium vulnerability, 28.72% is high vulnerability, and 11.36% is in the very high vulnerability range. The northern and southern parts of the plain aquifer are highly vulnerable. Therefore, controlling this area against pollution should be considered. Nitrate pollution in this area is also high, so this area requires more care and the imposition of certain restrictions. The central areas of the plain have a medium vulnerability potential, and the northwestern and southeastern areas of the plain have a lower vulnerability potential.

In this research, in the first part, effective characteristics in assessing the vulnerability of groundwater aquifers, including water table depth, recharge network, aquifer type, soil type, topographic slope, unsaturated zone constituents, and hydraulic conductivity, were used to implement the model. These were prepared as seven layers in ArcGIS software, and by weighting, ranking, and combining the above seven layers, the final map of aquifer vulnerability to pollution was prepared. Then, nitrate ion adaptation was performed on the final map of Drastic. Therefore, control of this area against pollution should be considered. Nitrate pollution in this area is also high, so this area needs more care and also the application of certain restrictions. The central areas of the plain have a medium vulnerability potential and the northwestern and southeastern areas of the plain have a lower vulnerability potential. Because the removal of pollution from groundwater resources is costly, the vulnerability zoning of the plain aquifer can be provided as a valuable tool to officials and trustees so that they can make the necessary decisions for land use and management of the plain aquifer. These decisions can include the management of agricultural fertilizers and urban wastewater to safer points and land use changes.

world and to some extent in Iran. A geosite is a landscape, a collection of roughness forms, a unique roughness, a rock outcrop, a fossiliferous zone, a specific fossil, caves, a crater created by a meteorite impact, a volcano, and even a mine . Geomorphological landforms have a high ability to attract tourism. The connection of landforms with the discussion of the expansion of civilization and ancient, historical, cultural monuments, as well as sports topics, doubles the capabilities of landforms in the field of attracting tourism (Yemani et al., 2013: 70). The purpose of the geomorphosite concept design is to identify landforms that have a special place and importance in describing and understanding the history of the earth's surface Also, they have scientific, ecological, cultural, aesthetic and economic values together and are exploited for the purpose of understanding and exploiting human tourism . Geomorphosites have scientific, cultural, ecological, economic, etc. values . The evaluation of geomorphosites is a topic that shows the motivation and interest of geographers around the world to try to focus on developing and maintaining the evaluation methods that they provided in the past. Identifying different forms of the earth, especially geosites, geomorphosites, geotopes, and other natural forms of the earth is one of the basic principles of nature tourism.

The desert and desert areas of Semnan province have the ability to be turned into geoparks due to their geomorphological heritage, but due to the spread and size of the region in the north and south of the province, research on geotourism and geoparks has been done on a case-by-case basis, and the officials at the province level cannot plan to attract tourists. have, and for this purpose, with careful identification and study, it is possible to provide the ground for geopark registration. The possession of land and natural resources, which is a suitable platform for the development of geo-tourism and eco-tourism in Semnan province, reveals the necessity of paying attention to the mentioned types of tourism and the importance of attracting tourists and exploiting its many benefits for the country and the province in this regard. By accurately identifying the geotourism capacities of Semnan Province, introducing suitable types of this tourism model in accordance with the region,

The current research has been applied with a descriptive and analytical approach to introduce and evaluate the geotourism capabilities of the region. In this research, in order to collect the data used, theoretical studies were first conducted with the aim of clarifying the framework of the subject, and in field studies (asking the people of Fan in the region) has been used to identify geosites, and KoboCollect software was used for field visits and registration of geosites and their specifications. Using this software, 90 geosites were identified and a separate birth certificate was prepared and completed for each of the geosites. After examining the birth certificate of geosites by expert experts and professors, 30 potential geosite points (Figure 2) were selected according to the criteria introduced as representatives of geosites, and based on the indicators in the models of Reynard (2013) and Brillha (2016), their valuation and geotourism position was determined.

Reynard's model and Braille's model describe the relationship between geomorphology and tourism by stating that geomorphology may be the primary or primary source of tourism or as a secondary source, as long as tourism infrastructure, tools (such as educational manuals) or services are used effectively for the primary purpose. will be examined. Final evaluation and comparison of Reynard and Braille modelsIn general, the oil well geosite is the most valuable geosite in both Reynard and Brill models; With its unique conditions, this geosite has received the highest possible points in both models. Geosite-73 is the second most valuable geosite among the studied geosites with 970 points in the Braille model and 3.93 points in the Reynard model. On the other hand, geosite 37 ranked 29th in the Braille model with 625 points and 30th in the Reynard model with 1.4 points, and it has the lowest overall value among the surveyed geosites. The first method, which was used by Brills (Zafiropoulos and Dernia, 2022), is considered a general-purpose method designed to evaluate any type of geosite considering a wide range of criteria. The inclusion of 12 criteria to evaluate the heritage value of the studied geosites leads to more objective results. On the other hand, Reynard's method includes public views, which in the present study clearly shows the lack of geo-environmental awareness and knowledge. These two methods provide different perspectives on the geoenvironmental value of a given geosite. The first method further deals with the geosite heritage of geological and tourism important places in a broader and deeper way. The second method, while it does not consider many parameters, also includes the opinion of visitors and the general public and education. The braille model is a model for measuring the capabilities of geosites in the scientific, educational, tourism and destruction risk sectors. Each of these sections have their own minimum and maximum points and coefficients, which should be taken into account in scoring. In the evaluation of the Braille model, geosites 68 and 73 both scored 970 points, and the geosite 33 scored the lowest.

In the current research, the existing geomorphological capabilities were evaluated and ranked from the geotourism point of view. In the meantime, the oil well geosite received the highest score in two methods and was ranked first, and this same geosite is ranked at the bottom with a score of 195 from the point of view of destruction risk. In general, it can be said that the reasons why the oil well got the most points in both methods is the scientific value in both methods, although other cases also have good points, but the important point is the lack of protection of all geosites in the study area.

This study aimed to identify the sources of aeolian sands in the Boralan Plain through an integrated approach combining wind analysis and sedimentological studies. Wind data spanning 20 years (2000–2020) from the Maku synoptic station, Iran, were analyzed. WRPLOT View 8 and a custom sand rose graphing tool were used to generate wind, storm, and sand transport roses, and to calculate wind indices, including drift potential (DP), resultant drift potential (RDP), resultant drift direction (RDD), and unidirectional index (UDI). To identify the origin of aeolian sediments, surface sand samples were collected from dunes, and grain-size and morphoscopic analyses were conducted, with distribution curves generated using GRADISTAT. Wind rose analysis showed that southeast (SE) and east (E) winds were most frequent, while storm rose analysis identified predominant erosive winds from the northwest (NW) and west (W). Sand transport potential was highest toward the east, with bidirectional winds (E-W) in autumn and winter significantly influencing aeolian sediment transport. Grain-size analysis revealed mean particle sizes ranging from 125 to 250 microns, with sorting ranging from well-sorted to poorly sorted, and distributions predominantly symmetrical. Sedimentological analyses identified the main sources of mobile sands in the Boralan Plain as alluvial deposits from the Qareh Su and Aras rivers, weathered basaltic flows, marginal alluvial fans, and eroded surfaces due to reduced vegetation from land-use changes. Overall, the aeolian sands originate from a combination of fluvial and aeolian processes driven by local geological and climatic conditions.

Urban environmental pollution in coastal areas significantly impacts water and soil quality, biodiversity, public health, and tourism activities. This study aims to identify and map pollution risk zones along the coasts of Anzali, Rezvanshahr, and Astara using a hybrid approach combining the Analytical Hierarchy Process (AHP) and the Random Forest (RF) machine learning algorithm. Fourteen critical criteria—including urban wastewater, population, human activity, coastal degradation, natural attractions, and tourism infrastructure—were selected from an initial set of 24 indicators through comparative analysis. Using expert judgment, the relative weights of each factor were calculated in Expert Choice software, and GIS-based spatial layers were generated in ArcGIS Pro. The pollution risk map was created by integrating the weighted layers. The RF model was trained using 70% of the high-risk zones as training data and 30% for testing. Model validation using ROC–AUC analysis showed excellent accuracy for the RF model (AUC = 0.97). The results revealed that Anzali County had the highest proportion of very high-risk zones, while Rezvanshahr and Astara also exhibited significant high-risk areas. The findings highlight the combined impact of human and natural drivers on coastal pollution and offer valuable insights for environmental management, spatial planning, and policy interventions to mitigate future risks.

Land Subsidence, as the downward movement of the land surface, plays an important role in shaping geomorphological features in different landscapes. Subsidence significantly affects the formation of river geomorphology by changing sediment distribution patterns, channel morphology, and basin evolution. Studies have shown that subsidence can lead to channel deviation, creating head-changing deviations, and increasing river gradients. In addition, subsidence affects sediment distribution, shoreline patterns, and channel mobility. The Tehran Plain aquifer has been subsiding over the past three decades, and the magnitude of this subsidence does not show a uniform distribution. Previous studies have attributed excessive groundwater extraction to the subsidence phenomenon in recent years. It seems that geomorphological diversity with different sedimentary characteristics can play a different role in the speed of expansion and secondary consequences of subsidence in this area. In order to directly observe the geomorphological effects of subsidence in the Tehran Plain, a field visit was conducted to about 20 points in areas affected by significant subsidence.

This area is part of the Tehran-Karaj aquifer and includes the cities of Islam Shahr, Shahriar, Qods and Baharestan, Tehran city and parts of the cities of Malard, Fardis, Robat Karim and Rey. The northern border of this area is limited to the slopes of the Alborz mountain range and includes the Tehran and Karaj alluvial fans and alluvial plain. In this study, Sentinel 1 satellite radar images in VV polarization were used in the period of 2022 with a time interval of 12 days. The number of selected images is 27 pieces. The small baseline radar interferometry technique (SBAS) and GMTSAR software were used to study Land subsidence. In order to directly observe the geomorphological effects of subsidence in the plain of Tehran, a field visit was conducted for about 20 points of areas affected by high subsidence.

The final results show a displacement rate of -163.338 mm to +38.3 mm per year along the satellite line of sight. According to the obtained displacement map, most of the subsidence of the Tehran Plain is seen in the central and western parts of the plain, with its maximum in the center and east of Shahriar County and northwest of Eslam Shahr County. The margin of the subsidence zone also extends to the southwestern part of Tehran City, showing a rate of up to 25 mm per year. The graph of the standardized cumulative groundwater level confirms periods of severe groundwater decline for all wells, although in some wells the water level continues to decline, while in others it has increased after a while, which may be due to groundwater consumption management or other possible changes such as sewage leakage into the aquifer. Photographs taken from the Karaj Riverside areas between the cities of Shahriar and Islamshahr, which are located in an area with high subsidence (between 80 and 150 mm per year), show the creation and expansion of gullies and the separation of the riverbed wall in the form of cracks in the wall and on its surface due to subsidence.

 A large part of the area affected by subsidence is located in Shahriar County, but due to the expansion of construction and agricultural lands, it is not possible to study its geomorphological changes in this area, and we can only focus on the effects of subsidence on human structures and ground cracks. The graph of the standardized cumulative value of the groundwater level confirms the periods of severe groundwater decline for all wells. Considering the dispersion of the selected well locations and the spatial and sedimentary differences, a different behavior of groundwater level changes compared to subsidence is evident and it can be concluded that the decrease in groundwater level is not the only reason for the dispersion of subsidence in the Tehran plain aquifer and that other different contributing factors such as sedimentary structure and soil type and human impacts such as possible sewage leakage are involved. Field visits to the maximum subsidence areas show geomorphological changes caused by subsidence in the form of cracks in the ground and river walls, as well as the creation of gullies in the walls of old river embankments.

A series of large-scale and long-term environmental processes, including seismic events, construction activities, land use changes and groundwater extraction, along with climate changes in low-lying coastal areas can lead to deformation, land surface and topographic instabilities. Coastal deltas are part of the landforms and landscapes that, due to the proximity of both land and water environments, leave visible effects against tectonic activities, which are related to things such as changing the pattern and place of formation of deltas due to the change in the course of coastal rivers, the formation of unbalanced coastal terraces in parts of The coast and the emergence of cut beaches in the form of sea loads can be mentioned. In this research, we investigated the geomorphic changes of the coastal plain of Chalus due to eustatic and geostatic activities and their effects on the changes of the plain and coastline in the Chalus region, the results obtained from radar processing, geodynamic data, changes in the level of underground water, geostatic activities, The eustatic changes of the Caspian Sea and the changes in land use show that the Chalus plain has risen under the influence of geostatic activity in the past two decades, and on the other hand, the Chalus coastline has moved towards the sea as a result of the changes in land use and the increase in river sediment load and the decrease in the level of the Caspian Sea. It has been significant that its result is significant in terms of environmental and economic damages. 

In this research, to analyze the karst geomorphology of Dimeh and Pirghar karst masses in Chaharmahal and Bakhtiari province located in the Zagros highlands, karst dolin were first modeled with the closed contour line method (CCLS) in karst masses. Then the modeling of karstification zones has been done using two approaches, fuzzy logic and multivariate linear regression. The validation results of the calculated figures related to the area under the receiver operating characteristic (ROC) showed that the fuzzy logic model based on the area under the curve (AUC) of both karst massifs has a higher degree of efficiency compared to the multivariate linear regression model. 

 

The natural environment has played a fundamental role in the decision-making of past humans to choose a place to live. Factors such as access to water resources, soil fertility, land slope, altitude above sea level, proximity to food sources, and accessibility to communication routes are among the most important variables that have been effective in locating human settlements. Examining these factors using spatial models not only helps to reconstruct settlement patterns in the past, but is also useful in designing predictive maps of ancient sites. In recent years, the use of statistical methods and machine learning to model the archaeological potential of different areas has become increasingly popular. By analyzing environmental data and recorded data from known ancient sites, these models are able to predict areas where the likelihood of ancient settlements is high. In addition to saving time and cost of field excavations, these methods allow archaeologists to focus on areas with higher priority. Different areas have different potentials for establishing settlements, depending on their natural conditions and historical background. Among the areas with a long historical background and a density of ancient sites is the city of Kahak in Qom province. Accordingly, the aim of this research is to identify areas susceptible to establishing ancient settlements in Kahak city using environmental parameters and spatial analyses.

In this research, the 30-meter SRTM digital elevation model, 1:100,000 geological map, and the layer of ancient sites identified in the region were used as the most important research data. The most important research tools were ArcGIS, TerrSet, and SuperDecisions. Also, the WLC-ANP integrated model was used in this research to identify areas susceptible to the establishment of ancient settlements. This research was conducted in several stages, in the first stage, the distribution of ancient sites was analyzed in relation to various environmental factors. In the second stage, based on the results obtained from the previous stages and using the WLC-ANP integrated model, the final map of areas susceptible to the establishment of ancient settlements in Kahak County was prepared. In the third stage, in order to verify the results obtained, the distribution status of the sites in the final classified map was evaluated.

The results of the assessment of the distribution of identified sites in the subunits related to the parameters used have shown that 81 and 46 percent of the identified sites are located in the classes less than one kilometer from the river and spring, respectively, and with increasing distance from the river and spring, the density of sites has decreased. In terms of the slope parameter, 60 percent of the identified sites are located in the slope class less than 10 percent, and with increasing slope, the density of sites has decreased. In terms of the height parameter, 38 percent of the identified sites are located in the altitude class of 900 to 1300 meters, and in a general trend, the density of sites has decreased with increasing height. In terms of the lithology parameter, the highest density of identified sites with 27 percent was related to alluvial material units. Also, in terms of the geomorphology unit parameter, 70 percent of the identified sites were related to the alluvial fan unit. According to the results, it can be said that areas near rivers, areas near springs, low-slope and low-altitude areas, northern slope directions, alluvial lithology, and alluvial fan units had the highest density of ancient sites.

According to the assessments conducted regarding the potential for establishing ancient settlements in the city of Kahak, the results show that about 403 square kilometers of the city (equivalent to 48.6 percent) had a great potential for establishing human settlements in ancient times due to its proximity to water resources such as rivers and springs, as well as suitable natural conditions such as altitude and low slope. In contrast, 125 square kilometers of the area (equivalent to 15.1 percent) had little potential for such settlements due to its distance from water resources and unsuitable topographic conditions. In order to assess the accuracy of the results of this analysis, the spatial distribution of the identified ancient sites was compared with the potential classes. Accordingly, it was determined that 30 sites (equivalent to 81.1 percent of the total sites) were in the very high potential range and 5 sites (equivalent to 13.5 percent) were in the high potential class. While none of the identified sites fall into the low or very low potential categories. Considering the above, it can be concluded that the analysis method used in this study has high validity and accuracy and can be used as an effective scientific tool to identify and predict areas susceptible to ancient settlements in the Kahak region. These results can pave the way for future archaeological studies and better management of the region's cultural heritage.

Land subsidence is a global geological hazard resulting from human activities and natural factors, requiring thorough investigation in many countries, including Iran, the United States, the United Kingdom, Australia, China, Egypt, France, Germany, India, Italy, Japan, Mexico, Poland, Saudi Arabia, Sweden, and the Netherlands. Iran is one of the most hazardous regions globally, experiencing numerous hazards each year. One of the risks that occurs due to climate change and population growth in plains is land subsidence. Reports indicate that 50% of Iran's plains (300 plains) are at risk of subsidence, causing significant problems for agricultural, residential, and transportation areas. While the consequences of land subsidence may not be as apparent as earthquakes or floods, its long-term and heightened impacts are more significant.In recent years, attention has been given to land subsidence in Iran, with numerous studies published on this topic. A preliminary review of the conducted research reveals their dispersion and lack of consistency. The importance of land subsidence and the abundance of scattered studies in this field prompted the authors to provide a systematic review of these studies. The systematic review approach aims to organize and integrate research findings from various studies in a specific domain to present new insights. Therefore, the main objective of this study is to comprehensively analyze the status of land subsidence in Iran using a systematic review approach. The systematic review approach is a research method that explores and extensively analyzes available resources in the studied field, providing reliable results.

The aim of the present study is to provide a comprehensive analysis of the status of land subsidence in Iran. To achieve this objective, a systematic review was conducted to assess the state of land subsidence in Iran. Systematic review is an essential tool for presenting evidence in a rigorous and reliable manner, making it suitable for gaining a comprehensive understanding of land subsidence. The literature for this study was selected based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework. PRISMA is a validated method for guiding systematic reviews of academic literature.

The rate of land subsidence varies in different provinces and time periods. For example, in Azarshahr, it is 2.1 centimeters per year, in Marand plain, it is 2 centimeters per year, in Salmas plain, it is 11 centimeters in 2019, in Ardabil plain, it is 4.4 centimeters per year, in Meshkin Shahr plain, it is 9.35 centimeters per year, in Khorramdarreh, it is 4 centimeters per year, in Abhar, it is 4.3 centimeters per year, in Qorveh plain, the average is 11 centimeters per year, and in Mahidasht, it is 3 centimeters per year.The systematic review of research findings indicates that the subsidence rate in Tehran ranges from 3 to 43 centimeters. Additionally, subsidence rates of 11 to 27 centimeters have been reported in Shahriar and 20 centimeters in Varamin. In Ghorveh, the subsidence rate is 6.28 centimeters per year, in Dindarlu, it is 30 centimeters per year, in Marvdasht, it is 5.2 centimeters per year, in Noorabad, it is 4 centimeters per year, in Jiroft, it is 12 centimeters per year, in Kerman, it is 6 centimeters, and in Minab, it is 13 centimeters per year. In Mahyar plain, the subsidence rate ranges from a minimum of 4.6 to a maximum of 2.8 centimeters per year, in Najafabad, it is 7.7 centimeters per year, in Abarkuh, the range is from 5.5 to 12 centimeters per year, and in Dezful, it is 9.5 centimeters peryear. In Jooyin plain, the subsidence rate is 4.6 centimeters per year, in Sabzevar, it is 2 centimeters per year, in Mashhad, the range is from 14 to 23 centimeters per year, in Neyshabur, it is 10 centimeters per year, in Gorgan, it is approximately 5 centimeters per year, in Semnan, it ranges from 10 to 13 centimeters per year, and in Eyvanki, it is 11 centimeters per year. In Hashtgerd plain, the subsidence rate is 7.4 centimeters per year, in Qazvin, it is 3 centimeters per year, in Qom, it is 3 centimeters per year, in Aliabad, it is 16 centimeters per year, and in Shazand, it is 6 centimeters per year.

Rivers are dynamic geomorphological systems that continuously change due to various influencing parameters. Morphological changes in the river channel primarily involve adjustments in channel width, depth, slope, and river planform. The extent of lateral migration of the river channel depends on factors such as bank resistance to erosion, the duration and magnitude of flow, the curvature radius of the channel, and the flow capacity to transport sediments. Quantifying geomorphological changes in rivers with an emphasis on flood hydraulics requires detailed analysis and complex modeling of the dynamic interactions between water flow, sediment deposition, and riverbed alterations. Flood severity, characterized by high discharge, significant flow depth, and extreme flow velocities, can have substantial impacts on riverbed structures, including changes in depth, width, channel meanders, as well as sediment transport and deposition. The Sefidroud River is one of the largest rivers in Iran, directly and indirectly affecting the lives of a significant population. Throughout history, there has been a strong inclination to settle near this river, with numerous urban and rural settlements located along its course. The occurrence of frequent floods in the past and the river's tendency to alter its channel, especially in the lowland regions, make the delineation of floodplains and prediction of future river behavior essential aspects of this research. Therefore, identifying and quantifying the geomorphological changes of the Sefidroud River and investigating the relationship between these changes and flood severity during mid-term return periods are key objectives of this study.

 Results  :

In the present study, four indices were calculated and used to quantify the river's morphological changes: channel braiding index (B), channel sinuosity index (P), lateral migration rate, and channel stability. The study reaches showed minimal variation in terms of the braiding index, with the Yasaval reach having the highest value, which is 0.07 higher than the Astaneh reach, which had the lowest value. The lower braiding indices of the Gilvan and Astaneh reaches, compared to Yasaval, can be attributed to the higher severity of human activities in the riverbed and the presence of the Sefidroud Dam upstream of the Astaneh branch. Regarding the channel sinuosity index (P), there is an inverse relationship between flow severity and shear stress with the sinuosity index. Reaches with lower flow severity and reduced shear stress tend to have higher sinuosity. Concerning the lateral migration rate, the results showed that this index is strongly influenced by the morphology and topography of the riverbanks. In the Yasaval and Gilvan reaches, which flow through mountainous regions, the lateral migration rate is lower (1.3 and 1.93, respectively) due to the rougher and more restrictive topography. The equations related to channel stability and migration rate indicate an inverse relationship: as the channel's migration increases, its stability decreases, and vice versa. Flood severity, which is the product of flow velocity and depth, can lead to significant changes in the river channel, meanders, and sediment distribution. The results indicate that, contrary to expectations, in areas with higher flood severity during a 25-year return period, river channel changes are less pronounced. This phenomenon is related to factors such as channel depth and longitudinal slope. Deeper channels, where flood severity is greater, exhibit higher stability and therefore experience fewer changes. In contrast, wider and shallower sections of the river, with slower flow, tend to undergo more substantial alterations.

 Discussion and Conclusion  :

Numerous studies have been conducted on river morphology changes across various regions worldwide, employing a wide range of methods. In this study, several of these methods were used to quantify and examine the geomorphological changes in the selected study reaches. However, a key aspect of this research is the relationship between flood severity and geomorphological changes in rivers. Most studies in this field have focused on the impact of one or several extreme flood events on river channel changes, typically employing a before-and-after comparative approach. However, this research utilizes hydraulic modeling, based on validated 1:1000 maps and hydrometric data, to comprehensively examine the overall effect of flood severity on river morphology and channel changes. The results were then compared with geomorphological change maps, providing a broader perspective on the relationship between flood dynamics and river morphology.The results indicate that the braiding index of the Yasaval stretch is higher than the other two due to lower human interference and the presence of sediment bars and multi-threaded flows. The sinuosity index in the Astaneh stretch was higher due to the floodplain morphology of the riverbanks, which also contributed to a higher lateral migration rate. In contrast, the Gilvan and Yasaval stretches, with their more confined banks, showed greater stability and lower sinuosity and lateral migration rates.The study also examined the relationship between the geomorphological indices of the river and flood severity during mid-term return periods. Contrary to expectations, in areas with higher flood severity, channel changes were less pronounced. This can be attributed to the influence of channel geometry and longitudinal slope. In deeper sections of the river, morphological changes are less likely, resulting in greater stability. Additionally, in steeper slopes, both base flow and flood flows exhibit higher velocities, leading to greater channel incision. Deeper channels are more capable of handling floods with shorter return periods, reducing the likelihood of overflow and the formation of new channels.

Geomorphological indicators are useful tools in evaluating and identifying the effects of relatively sudden or gradual tectonic activities. The behavior of the drainage network is one of the parameters that is very sensitive to tectonic activities and shows the effects of duration and intensity of these factors. Among the geomorphological evidences of active tectonics of drainage networks and their related features such as drainage pattern, drainage density, drainage anomalies, connection method (connecting angle of networks) and direction of networks play an important role in identifying active tectonics and their spatial differences. Many studies have been carried out in the fields of the effect of tectonic factors on the ratio of branches, drainage density, hypsometric integral of river networks, response of drainage networks, and characteristic of hierarchical anomaly, branching index, to investigate the tectonic impact in four drainage basins and related fields. In addition to these parameters, by using the research results of other researchers and the reconstruction of the paleoclimate, it has been tried to analyze the effects of the Quaternary changes by using the mentioned factors as modeling and conceptual techniques.

The Kurdan watershed in Alborz province is located between latitudes 35 degrees 55 minutes to 36 degrees 6 minutes north and longitudes 50 degrees 49 minutes to 51 degrees 5 minutes east, its area is 336.5 square meters. The highest elevation is 4059 meters in the northern part of the watershed and the lowest elevation is 1427 meters in the area where the river exits the mountain. Therefore, the height difference between the north and south of the basin is 2632 meters. This height difference has affected the variety of weather and temperature and other geographical features of different parts of this basin.Watershed is a small part of the sub-basin of the Shur River of Qazvin, related to the Salt Lake basin. The rains of this small watershed arecollected by the Kurdan River and directed to the outside. The main branch of this river named Duran originates from the south of Kahar Peak in the rough northeast corner of the Qazvin basin and the neighborhood of the Karaj River watershed.Analysis of these changes using field evidence and sources such as aerial photos, satellite images, topographic and geological maps, and other physical tools of this research and based on the hierarchical anomaly index (∆a), basin asymmetry index(AF),Branches (R), horizontal topography symmetry index of the basin (T), hypsometric integral (Hi) and drainage pattern of geomorphic parameters have been done. Along with these parameters, by using the research of other researchers and simulating thepast climate, it has been tried to analyze the effects of Quaternary climate changes by using the mentioned parameters as modeling and conceptual techniques.In general, in this research, to detect the active tectonics of the area, it was measured from the topographic maps and aerial photos of the area, and to communicate between the tectonic movements and the drainage network, necessary geological and geomorphic data through the interpretation of geological maps. Topography, aerial photos, satellite images and especially frequent field visits were obtained. In the next stage of this research, evidence of new tectonics in the drainage network of the region has been obtained, and neo-tectonic analysis in the Kurdan basin has been analyzed using analytical-comparative methods and the use of geomorphological techniques. First, the information layers of topographic maps 1:25000 was transferred to the GIS information system in the ArcGIS environment and using it, layers such as drainage network, slope, digital height model were extracted and the results were analyzed using the geological map and according to the values of tectonic indicators. obtained, the morphology of the river in the studied area has been evaluated and analyzed in terms of the amount of new tectonic activity.

Based on the analysis of morphological parameters and branching index R, considering the branching conditions and the number of these branches, it shows the continuous presence of important tectonic activities in this basin. Also, the high figure of this index fully confirms the high tectonic activity in this basin. In terms of this index, the presence of dense branches in this region shows that it has experienced relatively high tectonic activities. Therefore, the results of this research show that: the studied area has been strongly affected by neo-tectonic activities and climate changes. Based on the obtained results, it shows the high tectonic activity of the drainage network of the Kurdan watershed based on the changes in river morphology and the youth of tectonic activities with high elevations. It can also be said that the documentation of scientific findings has confirmed the modification of morphological forms under the influence of climatic processes.

The results of the morphometric analysis and the analysis of the findings of the studies conducted in this basin show that it has experienced high tectonic activity, and considering the changes in river morphology such as the left deviations, it can be said that this basin from the perspective of tectonic activities It is active and has a young topography despite the high elevations. Also, the climatic evidence in this region confirms that this basin has experienced a sequence of cold/hot and wet/dry periods and has left evidence of glacial periods. Therefore, it can be concluded that the climatic activities in contrast with the tectonic situation of this basin have mainly gradually and at times suddenly and severely affected the basin, and adjustments have been made in the effects of these processes with the activity of climatic parameters. Therefore, the drainage network of the Kurdish basin of this basin is mainly gradually and at times suddenly and strongly affected by tectonics, and due to climatic processes, changes have been made in the forms.

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

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

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

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

Rivers are very sensitive to changes in discharge and sediment load as well as tectonic forces. Many of the changes that occur over time in the morphology of the channel can be related to the mentioned changes. Morphometric analysis is the first step understanding the basin dynamic activity. Combined variables and indicators can be effective in identifying the complications and surface landform of river channels and show their temporal and spatial changes. In addition, in addition, geomorphological indices (Morphotectonic indices) are considered to be very useful methods in evaluating and recognizing tectonic activities and can provide quantitative results and quantitative description of morphometric features in The basin scale can be used to explain the structural controls, geological history and geomorphology and processes of its drainage network. In addition, the morphometric parameters of the basin play an important role in the hydrological processes governing the basin because it largely determines their hydrological response.

Zanjanrud is the main river basin completely limited to the area of ​​Zanjan province. The river originates from the heights of Soltanieh in the east and flows to the northwest and finally in the west of Rajein village it joins Qizil-Uzen. Regard to the objectives of the research, first, using the DEM of the basin (ASTER-DEM: 30m), the extractable sub-basins was identified in the WMS software environment. In this step the number of 107 sub-basins could be separated, of which 52 sub-basins were selected based on the minimum area of approx. 20 Km2 for the evaluation and analysis of shape indices and tectonic. These sub-basins were named according to the outstanding settlement inside them. After determining the shape indices and estimating and comparing the state of neotectonic of the sub-basins, a field survey was conducted to closely examine and validate the findings.

At the first, the shape of the studied sub-basins was quantified using different indices. Then, the morphology of the sub-basins was evaluated using different shape indices and then the different indices were checked in terms of correlation in terms of the results related to tectonic activity. Finally, the neotectonic of the sub-basins has been estimated using the results of the shape indices and the data related to the faults. The results show that the Kazbar sub-basin is most elongated sub-basin, which together with 7 sub-basins with very high elongation rate are located in the western half of the Zanjanrud basin.The frequency of sub-basins with the shape index 2 to 3 is in the SE half of the basin. Out of the 8 sub-basins with shape index less than 2 in the eastern half of Zanjanrud basin, 1 sub-basin is located in the northern part and 7 sub-basins are located in the southern part of the basin, which can be seen in the SE half. The upstream sub-basin is not included in the classification due to the unusual shape that cannot be compared with other sub-basins.

The results of classification of the indices shows that the accumulation of sub-basins with high rate of elongation and as a result with high neotectonic activity is in the NW part of Zanjanrud basin and especially in the northern side of this part.Out of the 51 sub-basins, the concentration of 8 sub-basins with mean index of higher than 5 and a total of 16 sub-basins with an average shape index higher than 3.5, indicates the highest level of neotectonic mobility in this part of the basin. This finding is consistent withthe region's latest map of active faults, in which the frequency of faults (including the Sohrein fault, the Qaracherian fault and the Kenavand fault) is in the NW part of the basin.According to the study results of the shape of the sub-basins, the SW side of the Zanjanrud basin has an average level of neotectonic activity. This finding, along with the results related to the NW part, can strengthen the hypothesis that the western half of the basin is more active than its eastern half. The neotectonic mobility in SE side of the basin is moderate and is higher than NE part of the basin. As previous studies have shown, many faults are involved in the morphology of the region.

Badakhshan region, located in the northeast of Afghanistan, has a complex geology. A catalog from 2011-2021 was prepared using the data of the Middle Asia seismic catalog with updates (1909-2011) from the website of the American Geological Survey. Considering the last earthquake with a magnitude of 7.2 in 2015, the coefficients of b were calculated to the maximum value of 1.0 and the value of 7.9 on the surface and in the depth, the increase in the numerical values of a and b in the central half has been completely evident. The results indicated that the current trend is opposite to the direction of the main fault in North Badakhshan (north-south direction). The most frequent earthquakes M≥4 occurs at a depth of 150-70 km, earthquakes M≥5 at a depth of 150-300 km, and earthquakes ≥6 at a depth of 150-300 km occur in the east-west direction. This area is exactly where the Pamir Corridor plate meets the center of Badakhshan. This shows that at the end of the Pamir Corridor from east to west, ruptures are being created at depths of 0-150 km. Two east-west and east-south trends are evident. Regarding the shallow earthquakes related to the upper 50 km of the crust, the dominant mechanism is of the normal type, which indicates the stretching of the crust in this section. According to the deep mechanism of earthquakes, the direction of the tensile force is in the east-west direction. This issue further confirms the issue of continental collision and then subduction towards the south of Badakhshan. The innovation of this research is the identification of seismic trends that have rarely been researched in the studied area, and its application is identifying high-risk areas for construction.

Floods pose significant risks as natural disasters on a global scale. In addition to climate change, anthropogenic activities have exacerbated the damaging effects of flooding over the past decade. Findings indicate that over 91 billion hectares of land in Iran are susceptible to flooding. Extensive hydrologic records reveal a total of 467 flooding events in the country up until 2002, contributing to a loss of 630 lives between 1982 and 1992. These alarming statistics underscore the necessity of studying and analyzing floods, as well as mapping inundation areas, in order to mitigate potential damage associated with future flooding events. One particular region in western Iran that has been heavily affected by recurring floods is the Kashkan River. This river traverses numerous urban and rural areas that are prone to annual flooding. Although various methodologies exist to investigate floods and identify areas susceptible to inundation, many of these approaches require data that may not be readily accessible. Consequently, this study employs the Height Above the Nearest Drainage (HAND) model to examine the flood-prone sections along the Kashkan River. Unlike other methods, the HAND model solely relies on a Digital Elevation Model (DEM), making it a promising and accurate technique for mapping inundation areas. By utilizing the HAND model, this research aims to identify specific sections of the Kashkan River that are prone to flooding. The findings of this study will contribute to a better understanding of flood dynamics in the region, enabling the development of effective strategies to minimize potential damage.

In order to examine the areas that are prone to flooding, we employed the Height Above Nearest Drainage (HAND) model. This model was originally introduced by Rennó et al. (2008) and operates by utilizing a Digital Elevation Model (DEM) to compute the distance between a grid-cell within the topography data and the nearest cell along the stream it drains into. By considering cells with HAND values below a specific threshold as inundated, we can identify areas that are susceptible to flooding. Notably, the HAND model offers the advantage of being raster-based, eliminating the need for the construction of cross-sections, which is a requirement for alternative techniques like HEC-RAS. For our investigation, we employed the Shuttle Radar Topography Mission (SRTM) DEM, which possesses a resolution of 30 meters. To validate the findings obtained from the HAND model, we employed flood maps generated from Sentinel-1 Synthetic Aperture Radar (SAR) data from March 2019. These flood maps were created using the Sentinel Application Platform (SNAP) software and the OTSU thresholding method. This method allows us to distinguish flooded areas within the study region and validate the results obtained from the HAND model.

The findings from this study indicate that a significant portion of the study area, encompassing 54.49 square km, is classified as highly flood prone. Additionally, an area measuring 31.78 square km is categorized as flood prone. Based on the HAND maps, it is evident that more than 30 percent of the study area is susceptible to flooding with varying intensities. The outcomes further reveal that the majority of both rural and urban regions situated alongside the Kashkan River are located within highly flood prone sections. Moreover, a comparison between the flood maps derived from Synthetic Aperture Radar (SAR) and the HAND results demonstrates that the HAND model successfully identified and classified the flood area in March 2019 as highly flood prone and flood prone. By examining the cross-section along the river, it becomes apparent that the inner banks of meanders are more susceptible to flooding when compared to the outer banks. Cross-section 1 analysis revealed that the sections with a high susceptibility to flooding are situated at higher elevations when compared to the maximum flood level observed in March 2019. This implies that in the event of more sever floods in the future, a larger portion of the areas along cross-section 1 will likely to be inundated. Additionally, the analysis demonstrated that during elevated flood flows, the outer bank of the meander is more prone to flooding compared to the inner bank. Similarly, in cross-section 2, the outer bank of the meander exhibits a greater extent of highly flood-prone areas compared to the inner bank. Furthermore, cross-section 2 findings indicate that the flood flow during March 2019 did not reach the upper limit of the highly flood-prone category. In contrast to the previous cross-sections, cross-sections 3 and 4 primarily experienced flooding along the inner bank of the meanders, and the HAND model also classified them as highly flood prone. These results suggest that the distribution of inundation in the Kashkan river is predominantly influenced by the underlying topography.

The findings indicated that both rural and urban regions situated along the Kashkan river exhibit a high vulnerability to flooding, with a propensity for inundation during flooding events. The results revealed the efficacy of the HAND model in accurately identifying the flood-prone segments of the Kashkan River. Analysis of cross-sections along the river revealed that the inundation patterns in mountainous meandering rivers are predominantly influenced by the underlying topography. Overall, the HAND model represents a swift and precise approach for delineating areas at risk of flooding, thereby assisting authorities in enhancing planning strategies and implementing effective measures for mitigating damages.

The wind erosion and the resulted landforms are the dominant landscape in flat and deep plains of Iran dry areas (Yamani, 2015). The importance of wind erosion in the deserts differs due to great variances in wind power (Goudie, 2013). This type of erosion which is controlled by the erosivity power of wind and the erodibility of impacted surfaces (sharma, 2010), is dangerous for three reasons: 1, the nutritious elements of the soil are destroyed and as a result the soil loses its power for keeping a conservative vegetation layer (Thomas, 2011). The deposition of eroded sediments can bury vegetation and river channels, pollute food and water reserves and also negatively impact the growth of vegetation, soil fertility, and the dynamics of ecosystem (Larney, 1998y; Worster, 2004; McTainsh & Strong, 2007 ). The transportation of eroded sediments through powerful winds can bring damage to buildings and products and also trouble visibility in roads and airports (Thomas, 2011).

In first step, the impacted area of fault spring in Daranjir playa are identified based on satellite images, Geology maps and field observations. In the next step, 100 milliliter of water was sampled for chemistry analysis from active spring across Bafgh – Poshte-badam fault (Kor spring). Thus, to determine the water table, chemistry analysis of the sediment and water samples across Bafgh – Poshte-badam fault, 4 points were selected for drilling and the locations of bores were determined by GPS. To this end, the sampling procedure across the fault was conducted by a hand auger with the length of 20 cm and diameter of 7.5 cm. In sum, four water samples and 22 sediment samples were collected. In the geomorphology laboratory, initially the amounts of TDS, EC, and pH in the sample waters were measured by a multi parameter device, version HI9811-5. To measure the amounts of TDS, EC and pH in sand samples, saturated paste method was utilized. Here, the samples were initially dried in a drying device, and then 50 grams of each sample was measured with an accurate scale and mixed with 50 millimeters of distilled water. In the following step, the distilled water was mixed with sediment samples and the amounts of EC and TDS was measured using the multi parameter device and other devices.

The results suggest that the active tectonic performance across Bafgh-Posht badam fault not only result in the emergence of springs across the fault but also lead to the reduction of groundwater and the creation of a wet zone across the fault in Daranjir playa due to the penetration of water to the aquifer. This wet zone across the studied fault caused a significant growth of shrubs and Tamarix mascatensis, and reduced the speed of wind in the examined area. Regarding this Pye & Tsoar and state that in desert areas the salinity degree of groundwater has an important role in the transformation and distribution of deserts’ vegetation. The analyses of the qualitative and quantitative characteristics of groundwater across Bafgh- Posht badam fault show that the minimum water table, TDS and EC across the fault are ,respectively. In fact, by injecting fresh water across the fault, the fault springs not only reduce the salinity of groundwater but also raise the the water table across the mentioned fault and bring the transportation of the sediments to a minimum level. As for this case, Silva et al., (2018) state that in areas with high water tables, the sand sources are limited and consequently the transportation of sediments reduces. Moreover, Kocurek & Nielson concluded that high water tables can reduce the transportable sediment by conserving surface moisture. In addition to the formation of vegetation, the increase of water level across the fault, the creation and change of Nebkha formation location are the main effects of spring faults which have a crucial role in controlling wind sediments. As a matter of fact, the fresh water of springs results in the formation of vegetation and this vegetation captures wind sediments and forms Nebkhas.

The results of this study show the strike-slip movement of Bafgh – Poshte-badam fault and the emergence of fault springs have a key role in controlling wind erosion and formation of eaolian landforms in Dar-Anjir playa. Indeed, the fault springs control the wind erosion in the present case study in three ways: 1: the formation of wet zone creates various types of vegetation and reduces wind speed in surface, 2: the raising of water table across Bafgh – Poshte-badam fault and the increase of the moisture surface impede the movement of sediment by wind and 3: With formation of nebkhas causes the aeoilan sediment accumulation around Shrubs.

How the first human settlements came to be is an important issue, and from different scientific perspectives, different answers can be given; because the creation or degeneration of these settlements is not the choice of individuals; it depends on countless human and natural conditions. Studies show that the establishment of human societies on the ground has always been done in order to achieve maximum natural resources such as water resources, adequate vegetation and access to arable land, this effort is undoubtedly based on the principles that today It is interpreted as the science of location. At the beginning of human life, natural hazards were unknown to humans until their occurrence. Natural are also safe. Natural disasters are born of natural elements and factors, but human profiteering intervention in nature affects the quantity and quality of many natural disasters. Considering the mentioned cases, environmental factors, especially geomorphology, have played an important role in locating residential areas throughout history. Accordingly, in this study, environmental factors affecting the distribution of ancient settlements in Piranshahr have been investigated.

In this research, in order to achieve the desired goals, a 30-meter-high digital model, a layer of ancient sites identified in the region (Masoumian, 2021), a 1: 100000 geological map and a 1: 50,000 topographic map of the region have been used. The most important tool used in the research was ArcGIS and also in this research the combined model of fuzzy logic and AHP has been used. This research has generally been done in two stages. In the first stage, after preparing the layer of ancient sites in the region, the location of ancient sites in terms of slope, slope classes, elevation classes, distance classes from the river, lithology units and geomorphological units are analyzed and thus the distribution status of sites Ancient has been analyzed in relation to environmental conditions. In the second stage, in order to identify areas prone to ancient settlements, the results of the previous stage have been used and using the integrated model of AHP fuzzy areas, a map of areas prone to ancient settlements has been prepared.

In this study, in order to investigate the effects of environmental conditions on the distribution of ancient settlements, first the location of 67 ancient sites in Piranshahr city has been determined. According to the results, a large part of the ancient settlements are located in the slope classes less than 10%, so that 32 ancient sites (equivalent to 47.8% of the identified sites) are located in this class. In terms of slope, a large part of the ancient settlements are located in the northern directions so that 36 ancient sites (38.8% of the identified sites) are located in the northwest to northeast. In terms of height, a large part of the ancient sites are located in the altitude classes of 1250 to 1650, so that in this category there are 56 ancient sites (equivalent to 83.6% of the identified sites). In terms of distance from the river, a large part of the ancient sites are located near the river, with 48 ancient sites (equivalent to 71.6% of the identified sites), located less than 500 meters from the river. They had. Lithologically, a large part of the settlements are located on Quaternary alluvial sediments, so that 37 ancient sites (equivalent to 55.2% of the identified sites) are located in this unit. Also, in terms of geomorphology, a large part of the ancient sites are located in the alluvial plain unit, so that 37 ancient sites (equivalent to 55.2% of the identified sites) are located in this unit.

Environmental conditions have played an important role in the settlement of residential areas in the past and today. Considering that the knowledge of the effective factors in location selection has an important role in various planning, in this study, the effective environmental factors in the establishment of ancient sites in Piranshahr city have been analyzed. Based on the results, the distribution of ancient sites was directly related to environmental conditions, so that the highest density of ancient sites in low-slope areas, low-lying areas, areas near the river, north slope directions, unit Quaternary alluvium as well as unit of alluvial plains. According to the results obtained at this stage, areas prone to the establishment of ancient settlements in Piranshahr city have been identified that based on the results, the middle areas of Piranshahr city due to the conditions, are prone to the development of ancient settlements. The results of this study have shown that environmental conditions in the past have played a major role in the distribution of residential areas and by examining the environmental conditions of each area to a large extent can be found the existence of ancient sites in that area.

In this study, the occurrence potential of rainfall-induced shallow landslides in the Babolrood basin has been investigated. In this basin, due to the mountainous topography and the presence of loose organic soils, the potential of such landslides is high, and landslides of different sizes occur every year after long and intense rainfalls. These landslides, which start with the sliding mechanism in the upper parts of the soil cover, immediately turn into earth/debris flows, and from their joining together, large flows may form downstream of the basin, which is considered a destructive phenomenon. In this research, to investigate the effect of rainfall on the occurrence of shallow landslides and flows, the TRIGRS program, which is a comprehensive and grid-based program for slope stability analysis using the infinite slope method, has been used. In this program, the effect of rainwater penetration into the soil and runoff caused by rainfall, which are important parameters in the occurrence of shallow landslides and subsequent flows, are also fully considered and this natural phenomenon is fully simulated. The input data required for this research includes topographical data of the basin, geological and hydrogeological properties of soil units, and rainfall data in the region, which are prepared in the form of appropriate text files and GIS maps. The output of the Triggers program includes maps of the spatial distribution of the minimum safety factor, the depth of the failure, and the pore water pressure at the failure depth, which are prepared in the form of text files and can be interpreted in GIS-based software. The results of this study showed that in the high and steep parts of the basin, wherever there are soils on a bedrock rich in clay minerals (such as mudstone, marl, and shale), the potential for shallow rainfall-induced landslides is high. In the field studies, a good agreement between the results of this study and the experiences obtained from field observations of landslides caused by rainfall in the region was obtained in terms of their spatial distribution and time of occurrence.

Terraces are important archives for paleontology. In this research, the paleotemperature changes and discharge frequency of Jajroud basin in the northeast of Tehran have been investigated based on the sedimentology and geochemistry characteristics of the reservoirs. First, the sediment samples were analyzed with calcimetry, EC, XRF, and PH techniques, and then these data were correlated with the indices of salinity, chemical weathering, acidity, and maturity of the sedimentary layers of the defenses. The results show three periods of flow changes, during the alternation of cold and warm periods of the river. One is at the peak of the glacial period, when the accumulation of snow and ice in the mountainous part has reduced the discharge (before the Holocene). In the second stage, by passing from the glacial period to the warm period (11 to 8 thousand years ago), Jajrud has experienced its highest discharge. Because the melting of glaciers has been accompanied by rainfall. The existence of very coarse layering in the early Holocene terraces indicates the occurrence of floods in this period. In the third stage, the dominance of recent hot and dry conditions (8 thousand years ago until now) and the lack of glacial deposits have led to a decrease in river flow. Based on this, the geochemical studies of the reservoirs can provide valuable data to recover the dynamic changes of flow and discharge during the Quaternary period and can be generalized to other similar basins.

The presence of water resources, particularly rivers, significantly influences site selection. Throughout history, settling near rivers has brought numerous advantages, but it has also posed certain risks. This study focuses on the sub-basins southeast of the Caspian Sea. Initially, we explore the connection between the layout of ancient settlements and the drainage networks. Additionally, we analyze the relationship between flood risk and the settlement patterns of these ancient sites by estimating the flooding risk based on linear, areal, and relief aspects. This research marks the first time such an analysis has been conducted. The findings underscore the importance of proximity to rivers in site selection, with areas close to rivers with lower stream orders being the most favorable for settlements. The study reveals a decrease in the frequency of sites near higher stream orders in relation to flooding risk. Conversely, there is an increase in the frequency and density of ancient sites near the first stream orders and at greater distances from the rivers, coinciding with an elevated flooding risk in the sub-basins. These results indicate that the inhabitants of the southeastern areas of the Caspian Sea sub-basins were cognizant of the flooding danger and factored it into their decision-making when selecting settlement sites

Neglecting coastal erosion can lead to environmental hazards that are among the main factors affecting human communities and facilities. Paleontology researches demonstrate tens of meters fluctuation in water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use including lowlands (estuaries of rivers, gulfs and progradation) and sandy uplands. In this study, spatiotemporal analysis was used to analyze the changes in sandy coasts in relation to land use changes and the adaptation of the coastal line in the study area within the framework of coastal cells. Land use data for the years 1975 and 2020 were extracted using SAGA and ENVI software, and land use changes were analyzed using IDRISI software. The results showed that 68 kilometers of the coast have been unstable, with the majority of these areas experiencing erosion due to human activities (land use changes), including cells 10 and 3. Also, the erosion of unstable cells 5, 6, and 1 is of natural erosion type (sea level changes), and the erosion of unstable cells 9 and 2 is of natural-human erosion type. The remaining 24 kilometers of the studied coastline have been stable coasts, with the majority of coastal areas experiencing natural erosion (sea level changes), including cells 7 and 8. Cell 4 has had sustainable coasts with erosion of a natural-human type.

The natural hazards are impossible to avoid, and infrastructure elements and communities cannot be made totally invulnerable. The only viable solution is the complex risk analysis and subsequent development of combination of mitigation and adaptation strategies Floods are the most common natural disaster type worldwide. Between 1995 and 2015, 2.3 billion people were affected by floods, con siderably more than any other type of natural disaster event. In general, the Givi Chai basin includes two cities, Khalkhal and Kausar. In recent years, floods have caused damage to gardens and facilities due to spring and summer rains to the extent that the villages that are located under the Sangur Chai basin because of being located at the source of the rivers and mainly in the course of the rivers are affected by floods; also in the whole basin due to droughts and the destruction of vegetation and the increase of man-made areas, the amount of impermeability has increased. Considering that Khalkhal is a mountainous area and is one of the areas sensitive to landslides in Azariaijan region, heavy rainfall and floods can wash away the slopes of this area.

The Givi Chai basin in the south of Ardabil province with an area of 1554 square kilometers is one of the 3rd degree basins of Sefidroud, which is located in the geographical coordinates of 48°4' E longitude to 48°38' E longitude 37°27' N latitude 37°55' N latitude. In order to achieve the goals of this research, firstly, the theoretical foundations and the works done in connection with flood zoning of basins in Iran and outside Iran were examined. Many variables are effective in the flood of basins. In this research, from the 1.100000 geological map, the slope maps were obtained using the digital height model map; the land use map was obtained through the classification of the  Maximum Likelihood  in ENVI software. In addition, using the digital model of the height of resolution  to extract, a drainage density map was prepared using the Line density tool. In this research, using the FAHP fuzzy hierarchical analysis model, Expert CHOISE software was used for weighting the layers, and finally, a map was prepared in the Arc GIS environment using gamma 0.5, 0.7 and 0.9The basin was flooded.

After preparing the effective factors for zoning the flood potential of the basin, the gamma fuzzy operators of 0.5, 0.7 and 0.9 were used. 37 floods have occurred in the studied basin from 1365 to 1399 in different parts and villages, which caused the destruction of rural houses, gardens, agricultural lands and livestock. In order to determine the final flood map, points were randomly selected on the zoning map, then the correlation level was obtained based on the specified points with each of the criteria in the ARC GIS software. Based on the results obtained from the correlation, the highest correlation level is related to gamma 0.9. Vegetation has the highest correlation of 0.5 and lithology has the lowest correlation with gamma of 0.9 and 0.062. Also, the last flood occurred in the studied basin in the villages of Mustafa Lo, Bolokan, Morestan and Khoda Qeshlagi, which are located in the high-risk zone according to the final flood zoning map.

In this research, using the FAHP model, flood potential zoning has been evaluated in Givi Chai basin. The data of height, slope, lithology, precipitation, vegetation, soil hydrology, distance from the river, drainage density and land use have been used for flood zoning. After preparing the zoning map, the studied basin was divided into five classes based on the severity of flooding: very low, low, medium, high, very high. The results obtained from the flood zoning of Givi Chai basin have shown that the largest area of the studied basin, which is 0.9 gamma scale, has the highest correlation. The strata with very low, low and medium potential, gamma 0.5  0.7, were showed. cover the area of Givi Chai basin. Also, the final flood map of the basin was validated with the villages that have been damaged by floods in recent years. The areas which are more exposed to floods are in the regions that have very low permeability in terms of lithology and hydrology of the soil and in the areas where the vegetation cover as less as.

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

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

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

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

The hydrograph shape, volume, peak discharg, and time to peak are important factors that should be considered in flood prediction and surface - water management problems. Rainfall and watershed characteristics affect runoff, and thus, hydrograph aspects. Numerous models have been developed to estimate hydrographs based on a variety of parameters. The PGIUH model is a geomorphologically - based model that has a probabilistic structure applying Strahler ̓s stream ordering scheme and Horton's laws and overland/streamflow travel times of different overland/stream orders to predict hydrographs. In the hydrological literature, the watershed response time to the rainfall is commonly characterized by the concepts including " time of concentration", "lag time", and"travel time", and the latter is applied in the PGIUH model to refer to the time it takes water to travel from one location to another; both on overland surfaces(overlandflow travel time) and in streams(streamflow travel time). .Different physically and empirically - based relationships have been developed to estimate travel time. Regarding the invariable probabilistic structure of the model, one can test the computational accuracy of the various travel time relationships based on the results of the model runs in comparison with observatory rainfall-runoff data The aim of this paper is to assess 10 travel-time relationships (5 overlandflow and 5 streamflow relationships) by comparing the estimated hydrographs with 10 observatory hydrographs in the Amameh watershed, located in the Alborz mountains, northern Iran. To reach the goal, some observatory hourly rainfall-runoff data of the watershed were obtained from two companies related to Iran ҆ s Ministry of Energy and 10 appropriate data were separated. For each of the runoff data, the total runoff ordinates were separated from the baseflow to derive the direct runoff hydrograph (DRH). Knowing the runoff depth produced by each event, the hourly effective rainfall amounts of that event were determined using the 𝜙-index, so that the total of all effective rainfall amounts of the whole rainfall duration would be equal to the runoff depth.On the other hand, the geomorphologic, topographic, and hydraulic paramaters needed to be used in the probabilistic structure and travel time relationships were obtained from the 12.5 m digital elevation model (DEM), the Google Earth satellite images and the previous papers regarding the study area. Different combinations of travel time relationships were applied at numerous model runs (One overlandflow plus one streamflow relationships at each run) to derive various IUHs. The hydrograph ordinates were obtained by multiplying the hourly effective rainfalls by the IHUs` ordinates and were compared with observed hydrographs statistically using such criteria as root mean square error (RMS), coefficient of efficiency (CE), error of peak discharge (〖Eq〗_p), and error of time to peak discharge (〖Et〗_p). The results showed that overlandflow travel-times did not contribute significantly in the hydrograph characteristics (in terms of peak flow, time to peak, and runoff volume), however, the effect of streamflow travel times, especially those related to the main stream has been decisive. This could be due to the short water flow paths, and thus, travel times on the overland surfaces, and consequently, least contribution of the overlandflow in the time of concentration at each event as opposed to the streamflow Also, no of the streamflow travel time relationships has simulated all the events accurately. Some of the relationships (the Bransby-Williams and the Gupta et al with gamma of 0.6 to 0.7 relationships) have estimated more frequent normal rainfall-runoff events more precisely wich is represented in better mean statistical results of the 10 simulations and some others (the Kirpich, Johnston-Cross, and the Gupta et al with gamma of 0.2 to 0.4 relationships) have done the same for more intense less repeated events with higher peak discharges.This is because various events result in different streamflow velocities, and thus travel times, and various relationships have estimated streamflow travel times, especially those of the main stream, differently. Also, the the types of parameters used in the relationships have affected the results The watershed area (A) parameter involved in the Bransby-Williams relationship has led to more accurate average results obtained from the simulation of 10 rainfall-runoff events and the effective rainfall intensity (i_e ) parameter used in the Lee et al relationship has, unlike other relationships, led some of both the more frequent low intensity and more intense higher discharge events to be as of its best estimations. It is concluded,thus, that not a single streamflow travel time relationship can best estimate all the rainfall-runoff events in the PGIUH model, however, there may be one relationship that can be best adapted to the mean hydroclimatological conditions in a watershed and lead to best mean statistical results among others. For more rare events, other relationships whose results are far from mean hysroclimatological conditions of the watershed can be applied