Geomorphology
Nayer Teymuorzadeh; Majid Dadashi Rostami Sales
Abstract
Urban development is one of the important issues raised in the field of planning, and in the world it means improving productivity and better use of land and space, and it is influenced by factors including natural factors, such that the development of cities with natural bedrock and geomorphological ...
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Urban development is one of the important issues raised in the field of planning, and in the world it means improving productivity and better use of land and space, and it is influenced by factors including natural factors, such that the development of cities with natural bedrock and geomorphological effects is facingDue to the increase in population and the need to use the land around us, it is necessary to make intelligent planning in the field of sustainable urban development in terms of geomorphological phenomena and hazards. The existence of geomorphic hazards and the dynamics of the natural environment sometimes make it difficult to evaluate all factors at the same time in order to determine the appropriate location, so the use of efficient methods is one of the planning measures for urban development.The purpose of this research is to locate the physical development of Sufian city based on geomorphic factors using the AHP-Fuzzy model. To do this, the desired layers, elevation classes, slope, slope direction, lithology, distance from the fault, distance from the waterway, drainage network , land use, distance from the road was prepared.Then weighting was done in Expert choice software. Criteria of distance from fault with coefficient (0.218), distance from waterway (0.191), land use (0.155), distance from road (0.130), drainage network (0.102), slope (0.075) ), lithology (0.063), elevation classes (0.055), slope direction (0.011) are respectively the most important influencing factors in the physical development of Sufian city.By combining the results of AHP-Fuzzy and GIS, the studied area is divided into 5 unsuitable floors with an area of 15/90, relatively unsuitable 16/18, relatively suitable 16/59, suitable 16/53, very suitable 67 / 31 square kilometers were prioritized, the northern and eastern parts are in unsuitable areas and the central and southern parts are in very suitable areas.
Geomorphology
Leila Aghayary; Sayyad Asghari Saraskanrood; Batool Zeinali
Abstract
Flood is one of the most common natural hazards that causes many human and financial losses all over the world every year. In order to reduce the damages caused by floods and flood management, it is necessary to assess the possibility of danger and prepare maps of possible danger areas. Flood-flooding ...
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Flood is one of the most common natural hazards that causes many human and financial losses all over the world every year. In order to reduce the damages caused by floods and flood management, it is necessary to assess the possibility of danger and prepare maps of possible danger areas. Flood-flooding potential zoning is one of the methods that can be adopted to reduce the risks caused by floods. In recent years, many destructive floods have occurred in Garami county. For this reason, in order to manage floods, reduce damages and use water resources correctly, the flood potential of Germi county has been studied. In this study, 9 factors of slope, slope direction, height, precipitation, distance from the river, density of the river, lithology, distance from the city and village and land use were identified as effective factors for causing floods in the region. Standardization of maps was done using fuzzy method and zoning of prone areas was done with Aras multi-criteria algorithm in Edrisi software environment and according to the results of flood risk zoning; The criteria of lithology, land use, slope, distance from the river are the most important factors involved in creating the risk of subsidence of the study area with the weight coefficient of 0.853, 0.808, 0.674 and 0.4867 respectively, and 189.70 and 189.70 respectively. 20/388 square kilometers of the area has a very high probability of danger.
Geomorphology
Mousa Abedini; Aboozar sadeghi
Abstract
The aim of this study is to calculate the nocturnal urban heat island (UHI) and its relationship with urban land use in the metropolitan area of Tabriz. Landsat satellite data and Sentinel 3 data were used for this research. The Landsat satellite data was processed in ENVI 5.3.1, and the Sentinel 3 data ...
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The aim of this study is to calculate the nocturnal urban heat island (UHI) and its relationship with urban land use in the metropolitan area of Tabriz. Landsat satellite data and Sentinel 3 data were used for this research. The Landsat satellite data was processed in ENVI 5.3.1, and the Sentinel 3 data was processed in SNAP software, with further statistical calculations and outputs performed using ARCGIS 10.8. In the Landsat data, the minimum temperature was 5.14°C and the maximum temperature was 23.91°C, with the highest temperatures observed in bare land, transportation, agriculture, industrial, residential areas, as well as low-lying areas and areas lacking vegetation cover. The highest percentage of area with temperatures ranging from 15.16°C to 17.88°C was approximately 45.75% of the city. Areas with temperatures above 19°C covered an area of approximately 31.45 square kilometers, which accounts for 12.58% of the city. In the Sentinel data, the minimum temperature was 12.84°C and the maximum temperature was 21.62°C, with similar land use patterns to the Landsat data. Areas with temperatures ranging from 17.29°C to 18.45°C had the highest percentage of area, and areas with temperatures above 19°C covered approximately 17.06 square kilometers, accounting for 6.82% of the total area. Based on the results, which showed similar temperatures and land use patterns in both satellite data, it can be concluded that either satellite can be used for extracting the urban heat island (nighttime temperature).
Geomorphology
elhame ebady; Fariba Esfandayari Darabad; sayyad Asghari; Raoof Mostafazadeh; Elham mollanuri
Abstract
One of the important conditions for optimal use of land is obtaining information about landuse patterns and their changes over time. Landuse is usually defined based on human use of land, emphasizing the role of land in economic activities. Today, remote sensing technology is considered as the main element ...
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One of the important conditions for optimal use of land is obtaining information about landuse patterns and their changes over time. Landuse is usually defined based on human use of land, emphasizing the role of land in economic activities. Today, remote sensing technology is considered as the main element in landuse monitoring. The aim of the current research is to extract landuse maps for the years 2000 and 2021 in FirozabadKhalkhal region and to investigate the changes made in the studied time period in the region using the images of ETM and OLI sensors of Landsat. Also, checking the capability of basic pixel and object-oriented methods for landuse classification is another purpose of this study. In the current research, the object-oriented technique nearest neighbor algorithm and the vector machine method supporting the pixel-based algorithm have been used for landuse classification. Then, to verify the accuracy of these two methods, the overall accuracy and Kappa were extracted. The results of this evaluation show the high accuracy of the object-oriented method in extracting land use classes. Based on the results of the detection of landuse changes in the studied time period, the highest amount of changes occurred is related to the use of good pasture to poor pasture with a value of 51.72 square kilometers, followed by forest to good pasture with a value of 30.11 and the lowest changes It is related to the use of pasture and water with the amount of 0.03 square kilometers. The reasons for these changes are the increase in population, indiscriminate grazing of livestock, incorrect and illegal use of different lands. The use of more parameters such as scale, shape, compactness, color, texture, smoothness criterion and pattern for landuse classification in the object oriented technique can be considered as an innovation of the present study.
Geomorphology
sayyad asghari; shiva safari; elham mollanouri
Abstract
Land displacement is known as one of the most obvious invisible effects of natural earthquake hazards. In the present study, the radar interferometric technique (SBAS) using the images of Sentinel 1 (2018 to 2021) was used to estimate the land subsidence, and the Landsat 8 image of 2018 was used to extract ...
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Land displacement is known as one of the most obvious invisible effects of natural earthquake hazards. In the present study, the radar interferometric technique (SBAS) using the images of Sentinel 1 (2018 to 2021) was used to estimate the land subsidence, and the Landsat 8 image of 2018 was used to extract the land use classes in a part of the Sarab county. Also, the data obtained from the regional water organization has been used to investigate the condition of underground water in connection with the subsidence caused by displacement. According to the findings and survey of the land use map of the study area, the subsidence can be seen in different places and it reaches 9 cm per year around the agricultural areas and pastures. Also, in some places, the rising rate is estimated up to 12 cm. Examining the condition of aquifers shows a drop in the level of underground water in most stations, especially a sudden drop since the beginning of 2018. Considering that the direct relationship between groundwater withdrawal and subsidence has been fully proven; But after the 5.9 magnitude earthquake in November 2018, sudden changes have occurred in the subsidence of the region. Therefore, it seems that the subsidence of the region is more affected by the earthquake.
Geomorphology
mojgan entezari; shokoh Esteki; Hamide Gholamhaydari
Abstract
A major cause of landslide and relevant losses and fatalities is inappropriate land management, especially in mountainous areas and valleys. In this study, risk-vulnerability superimposed model was used to investigate the probability of occurrence of fatal landslides in Tarom Watershed. The risk-vulnerability ...
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A major cause of landslide and relevant losses and fatalities is inappropriate land management, especially in mountainous areas and valleys. In this study, risk-vulnerability superimposed model was used to investigate the probability of occurrence of fatal landslides in Tarom Watershed. The risk-vulnerability superimposed model has been formulated to evaluate the landslide risk and vulnerability. These factors include topography, geology, number of streams, rainfall, frequency of faults, land use, density of roads, population density, and construction density, which were considered and analyzed in the present model. According to the model output (i.e., risk-vulnerability map), it was figured out that the eastern and northeastern parts of Tarom Watershed are exposed to highest levels of risk and vulnerability. That is, occurrence of a fatal landslide with financial losses is more probable in these areas, as compared to other parts of the watershed. Results of the present research showed that 17%, 35%, 23%, 16%, and 9% of the entire watershed area were classified as being exposed to very low, low, moderate, high, and very high risk-vulnerability levels, respectively. Advantage and superiority of this model over other models and methodologies for landslide study is simultaneous consideration of landslide occurrence risk and vulnerability of the study area to the landslide, making it capable of determining the areas of higher probability of fatal landslides with financial losses.
Geomorphology
Fariba Karami; majid ranjbari
Abstract
The rivers are the most important supplies of fresh and agricultural water in the cities and villages. The importance of chemical quality of waters is becoming increasingly important due to the increase and diversity of Anthropogenic activities in the urban and rural environments. Therefore, the current ...
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The rivers are the most important supplies of fresh and agricultural water in the cities and villages. The importance of chemical quality of waters is becoming increasingly important due to the increase and diversity of Anthropogenic activities in the urban and rural environments. Therefore, the current study aimed to investigate the trend of land use changes and the chemical quality of surface water in a period of twenty years in the Qaranquchai River in Hashtrud Ccounty. The Qaranquchai is one of the sub-basins of Qezel Ozen River in the northwest of the country. In this research, Land use maps for the years 2021 and 2001 were prepared and drawn using Sentinel 2 and Landsat 7 satellite images, and were examined their changes. The chemical quality data of surface water in the hydrometric stations of the Qaranquchai basin, including Mg, Ca, EC, TDS, Cl, HCO, SO4, K and Na were obtained from the Regional Water Organization of East Azarbaijan province from 2000 to 2020. Then, their changes over 20 years were analyzed using the Mann-Kendall test. The results of the analysis of land use changes showed that in 2001, the largest area of land use was pasture, while in 2021, rainfed land had the largest area in the Qaranquchai basin. In fact, during the studied years, with the increase of rainfed agricultural land from 38% to 53.1%, pasture land decreased from 60.17% to 42.3%. The results of the investigation of the changes of the chemical quality indicators of the water in the hydrometric stations in the Qarangochai river in the studied time period, showed that the trend of changes was increasing. The result of the increasing process of each of the anions and cations in the river water has caused its quality to decrease.
Geomorphology
Masomeh Rajabi; Shahram Roustaie; sara mataee
Abstract
Land subsidence as a geological and geomorphological disaster has serious negative effects in many countries and regions of the world. In this research, it was tried to use 5 images of Sentinel 1 satellite for the period of 27/02/2017 to 01/01/2021 in order to measure and calculate the land subsidence. ...
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Land subsidence as a geological and geomorphological disaster has serious negative effects in many countries and regions of the world. In this research, it was tried to use 5 images of Sentinel 1 satellite for the period of 27/02/2017 to 01/01/2021 in order to measure and calculate the land subsidence. For this purpose, the land subsidence was investigated in four time periods, and the results of these four periods show the maximum amount of subsidence in the first period of 17 cm, in the second period of 8 cm, in the third period of 5 cm, and in The last period was 12 cm. In terms of the spatial distribution of subsidence in all periods, the maximum subsidence corresponds to the western and northwestern parts of the plain. In order to measure the land subsidence potential in the Kermanshah plain, a possible subsidence map was prepared using a hierarchical analysis model. In order to do this, eight factors affecting land subsidence were used, including water level drop, land use, well density, land slope, well geological log, slope direction, soil geology, distance from the river. The final map of the risk of land subsidence shows that 50% of the area of the plain is in the area with a very high and high probability of subsidence, with the highest level of water level drop and the thickness of sediments , the high density of the number of wells and the type of agricultural use that in It is located in the western and northwestern part of the plain. Due to the fact that this part of the plain is also in the maximum range of land subsidence. Therefore, the comparison of the maximum subsidence in both mentioned methods shows the complete matching of the results.
Geomorphology
masoomeh hadavand; mehran maghsoudi
Abstract
Off-road activity has increased significantly in different environments, especially arid regions and desert environments of the world, which can have negative effects on the ecosystem and different levels of desert landforms. This study is based on a qualitative, descriptive-analytical and quantitative ...
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Off-road activity has increased significantly in different environments, especially arid regions and desert environments of the world, which can have negative effects on the ecosystem and different levels of desert landforms. This study is based on a qualitative, descriptive-analytical and quantitative method that examines and monitors the trampling of landforms in desert areas and emphasises the need to protect the Lut Desert as a unique natural and cultural heritage against anthropogenic factors. This study was conducted at two levels. In the first level, the effects of off-road were studied and monitored in different years, and in the second level, the region wind and its relationship to the persistence of off-road effects on the land of desert forms were analyzed. This study was conducted in the northwestern region of Shahdad clots to Shoor river at a distance of three thousand meters from Shahdad-Nehbandan road. First, Aphrodite works were obtained in digital satellite images and then the density of Aphrodite works was obtained at certain intervals and compared on both sides of the road. During different years, these digitized works were examined and monitored. Based on the obtained results, it was found that the density of off-road effects has an increasing trend and shows that in recent years, off-road riding in the Lut desert has attracted more tourists. At a distance of three thousand meters from the road, the density of off-road effects is about 14%. And at a distance of two thousand meters 6%. And at a distance of three thousand meters 01%. The result shows that there is a direct relationship between the distance from the road and the off-road density.
Geomorphology
sayyad asghari; Elnaz Piroozi
Abstract
The danger of earthquakes causes irreparable damage to societies. Therefore, it is effective to prepare to deal with it by identifying vulnerable points. Ardabil City is not exempt from this rule due to the existence of many faults, seismic points, and non-compliance with standards. Based on this, the ...
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The danger of earthquakes causes irreparable damage to societies. Therefore, it is effective to prepare to deal with it by identifying vulnerable points. Ardabil City is not exempt from this rule due to the existence of many faults, seismic points, and non-compliance with standards. Based on this, the current research seeks to measure and evaluate the vulnerability of Ardabil City against the risk of earthquakes. For this purpose, first by examining research sources related to the subject, some of the most important factors affecting the occurrence of this phenomenon were prepared as independent variables. Valuation and standardization of the layers were done by using the fuzzy membership function and weighting of the criteria, using the CRITIC method. Finally, modeling was done using the MARCOS multi-criteria decision-making method. The results of the study showed, respectively; The factors of distance from the fault, land use, and distance from the earthquake center have the greatest influence on the occurrence of earthquakes in the region with the weight coefficient of 0.110, 0.104, and 0.102. In addition, according to the results of the research, 16.67% of the entire city of Ardabil has a high vulnerability potential and 30.27% has a relatively high vulnerability probability. Also, based on the results of the research, Ardabil city is at an average level in terms of the level of vulnerability to earthquake risk, the cities of Hir and Arallo are in the high vulnerability category and Somarin city is in the relatively high vulnerability zone. In addition, according to the findings of the research, 22.86 and 30.86 percent of the settlements and villages of Ardabil, respectively; In the area with high and relatively high vulnerability, 13.14% in the area with moderate vulnerability, and respectively; 22.28 and 10.86% are located in the area with relatively low and low earthquake vulnerability.
Geomorphology
Shima Vosoghi; Reza Zakerinejad; mojgan entezari
Abstract
Gully erosion is one of the most dangerous types of water erosion that destroys land and disrupts the balance of biological resources and the environment. In this study, the effective factors in gully erosion, prediction and zoning of gully erosion were investigated using the maximum entropy model in ...
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Gully erosion is one of the most dangerous types of water erosion that destroys land and disrupts the balance of biological resources and the environment. In this study, the effective factors in gully erosion, prediction and zoning of gully erosion were investigated using the maximum entropy model in Alamarvdasht watershed in Fars province. First, the location of the ditches was prepared through field surveys, aerial photographs and using Google Earth software images, and then the digital layer of the ditches was prepared in point form in the GIS software environment, and in the next step, the basin's physiographic indicators was prepared from in ARC GIS software. In this research, a soil texture map was prepared in GIS software with field operations in the study area and soil sampling and testing, and a land use map and vegetation density was prepared using Landsat satellite images, and then each of the indicators was The ditches were added in the GIS environment. To implement the maximum entropy model, 70% of the data were used for model training and 30% for model testing. In this study, the effect of each other indicators was determined using the Jack Knife test, and finally the most effective indicators were introduced. In order to validate the model, the direction of zoning of gully erosion in the studied area was evaluated using curve (ROC) and area under the curve (AUC). The results of this research showed that climate index, slope, geology, land use, direction of slope and height are the most influential indicators in creating ditch erosion and the AUC=0.997 is at an excellent level.
Geomorphology
asadollah hejazi; Atrin Ebrahimi
Abstract
The growth rate of urban population varies in different regions, and the role and position of cities in this area is very influential. Baneh is now considered one of the most important cities in the west of the country, which is very much considered, and due to its commercial location, the urban population ...
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The growth rate of urban population varies in different regions, and the role and position of cities in this area is very influential. Baneh is now considered one of the most important cities in the west of the country, which is very much considered, and due to its commercial location, the urban population and the expansion of its urban settlements are in a steady rising trend. Due to the geomorphologic situation of the area, the development of the settlement areas of this city is confronted, and as a result of the development of this city, many settlements are located in areas that are geomorphologically part of the hazardous areas. Considering the above mentioned cases in this research, the Baneh urban development process from 1992 to 2017 has been evaluated and the aim of this research is to evaluate the Baneh urban development process during the period 1992 to 2017, and then on the basis of it, the development rate the city of Baneh will be projected until 2030. The research data included Landsat satellite imagery of 1992, 2001, 2011, and 2017, as well as information layers including DEM 30m. Data analysis was performed using two ARC GIS and IDRISI software. In this research, using satellite imagery of land use, a study area was developed from 1992 to 2017, and based on these maps, the LCM model predicts the development of residential areas by 2030. The results of the present study indicate that during the period 1992 to 2017 the size of the residential areas increased from 9 km2 to 20 km2, as well as the results of the prediction of the development of residential areas also indicate that the size of the restricted settlement areas until 2030 It will reach about 27.7 square kilometers.
Geomorphology
mohamadali zanganehasadi; Rahman Zandi; Najmeh shafiei
Abstract
Salt domes are one of the unique geomorphological phenomena that are important in terms of economic development, environment and tourism.. It plays a significant role in earthquakes and land subsidence as an effective aggravating factor in tectonic activity. In this study, after identification and morphometry ...
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Salt domes are one of the unique geomorphological phenomena that are important in terms of economic development, environment and tourism.. It plays a significant role in earthquakes and land subsidence as an effective aggravating factor in tectonic activity. In this study, after identification and morphometry of salt domes in the southeast Fars region using eight tectonic indices, i.e., the activity status of the domes was evaluated. Then using differential radar interferometry, the amount of vertical displacement of the area was calculated. Finally, Geographically Weighted Regression was employed to determine the relationship between subsidence and collapse at salt domes. The results indicate that in addition to the movement of salt domes, tectonic subsidence factors have also been effective in the rate of vertical displacement in the region. The calculation of indices indicates that some salt domes are active, and the results of differential radar interferometry also indicate the region’s vertical displacement and tectonic activity. However, some salt domes, including salt dome S2 in the western part of Fasa township, with a high score in calculating the indices, were also in the range of uplift due to interferometry. Although other salt domes had a degree of uplift due to their unique characteristics, groundwater loss had caused the highest subsidence rate in salt domes S10, S4, S5, and S6. Therefore, besides the unique characteristics of salt domes, other factors such as subsidence due to groundwater overdraft which are about 70 meters, Comparing the two models, it shows that the GWR model with a coefficient of R2 of about 80% -99% and the lowest error of / 001. And OLS model with R2 coefficient shows about 0.23 and an error 0.07 and GWR model with higher accuracy confirmed the agreement between the two parameters
Geomorphology
gholam hassan jafari; Frozan Naseri
Abstract
Doline is one of the most characteristic and basic surface and morphological forms of karst, as a result of the chemical effect of water on limestone that occurs in different shapes and sizes. Dolines differ in morphological characteristics. In the present study, after identifying the valleys in the ...
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Doline is one of the most characteristic and basic surface and morphological forms of karst, as a result of the chemical effect of water on limestone that occurs in different shapes and sizes. Dolines differ in morphological characteristics. In the present study, after identifying the valleys in the karst areas of the Zagros, their dispersion and change of morphological characteristics such as length, width, area and depth in relation to altitude and climate, citing documentary sources such as geological maps 1: 100000, digital elevation model layer with strength 12.5 m resolution, satellite imagery, 1: 50,000 topographic maps, and 49-year-old Esfzari temperature and precipitation databases were analyzed in Arc GIS, Mapper Global, and Excel software. The study of different parameters of Zagros valleys in different altitudes and climates indicates that their shape and depth have been affected by Quaternary climate change. At lower altitudes, where water is more involved in dissolution than low temperatures, the dolines are nearly circular in shape and stretch at higher altitudes and the lower the temperature and the greater the likelihood of the doline turning into a glacial-doline circus, the more elongated the doline becomes. The compression coefficient of the dolines also indicates that their elongation and length increase with increasing height; in this way, at an altitude distance of 500-1000 meters, the ratio of circles for every 1000m increase in height increases by 0.8 and the compression coefficient decreases by 0.9. At an altitude distance of 1000-2000m, with each increase of 100m, the ratio of circles is 0.44 and the compression coefficient is 0.1. In the 3700-3000m floor, the circular ratio decreases by 1.2 with each elevation of 1000m, and the compaction increases by 1.3.
Geomorphology
Mohammad Hossein Rezaei Moghaddam; Masoumeh Rajabi; Masumeh Mousavi
Abstract
r optimal land use, it is necessary to be aware of land use changes and the type of land use; this is possible by assessing and predicting land use changes. The purpose of this study is to investigate the trend of land use change over a period of 18 years (2000-2000) and predict it using the Markov chain ...
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r optimal land use, it is necessary to be aware of land use changes and the type of land use; this is possible by assessing and predicting land use changes. The purpose of this study is to investigate the trend of land use change over a period of 18 years (2000-2000) and predict it using the Markov chain model for 2025, 2050 in the Yellow River Basin of Baghmalek city in Khuzestan province. To achieve this goal, first corrections (geometric, radiometric and atmospheric) and necessary processing were performed on Landsat satellite images of 2000, 2006, 2012, 2018; Then, land use maps for four time periods were classified into five classes: green space and gardens, barren lands, agricultural lands, water levels (sedgereh) and man-made residential areas. These changes were addressed using the Markov chain model for 2025, 2050. After making the necessary corrections on the Landsat images, the land use estimate showed that the highest percentage of the study area is barren lands and arable lands. The overall accuracy and kappa coefficient for 2000, 2006 and 2018 are above 0.80 and 0.92. .. The results of revealing the changes between the period 2000 to 2018 showed that barren lands with a rate of 823.51, green space and gardens with a decrease of 157.85 hectares. In contrast to the built-up areas of 439.59 hectares, 1356.56 hectares of arable lands and 404.94 hectares of water levels have been facing an increasing trend. Also, the results of the forecast using the CA-Markov model of land changes in the region for 2025 and 2050 showed that if the speed of land use change is the same as in previous years, in 2025 the use of built-up areas will be 1089.54, hectares of arable land. To 1154/52 hectares and surface water use will increase to 666/54; Landscaping and orchards will be reduced to 42/2012, barren land land use to 59,85279 hectares and in 2050 landscaping and orchards land use to be reduced to 192.62 hectares, barren land land use to be reduced to 8438.69 hectares, arable land land use Increase to 1243.73 hectares and surface water use increase to 8959.59 hectares of built-up areas to 1671/98 hectares. By examining land use change, valuable information can be obtained about man-made changes and natural factors. On the other hand, the prediction map derived from the Markov chain model is very important to provide an overview for better management of natural resources.
Geomorphology
Mousa Abedini; Vida Irani; Fariba Esfanyari darabad
Abstract
Introduction According to the results of this study, Tabriz metropolis does not have a favorable situation in terms of earthquake risk, and most densely populated parts of the city, especially the northern and central parts, are in very high and high vulnerability zones. Milani and Nemati (2015), ...
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Introduction According to the results of this study, Tabriz metropolis does not have a favorable situation in terms of earthquake risk, and most densely populated parts of the city, especially the northern and central parts, are in very high and high vulnerability zones. Milani and Nemati (2015), studied the geological indices, tectonics and seismicity of faults in Lut and Jazmourian basins. Their work’s results showed that both basins have active tectonics, but the western margin of Shahdad basin has high to medium activity and Jazmourian basin has little activity. Shayan and Zare (2013) investigated and determined the seismic hazard ranges in active alluvial fans by barbarian spatial analysis method, and the results of their research showed that Garmsar and Sorkh Sokoot faults have the highest seismic potential and Lalehzar and lower Qaleh mountain faults have the lowest. Rajabi and Aghajani (2010) investigated faults and seismicity and seismic hazard in the northeast of Lake Urmia. Their studies in the region led to three important classifications. Rabati et al. (2015) studied active tectonics using geomorphological indices in the Sefidrud basin of western Alborz and their results indicated that sub-basins corresponding to dense fault zones show high measurement indices. Data and Method In order to achieve the objectives of this study, the data of topographic map 1: 25000 of the surveying organization, region’s geological map of 1: 100000, region’s aerial photographs of 1: 50000, 1: 20000 and 1: 40000, Landsat 8 satellite images related to the year 2020, as well as digital elevation model map were used. Using the existing relationships, geomorphological indices were calculated and necessary analyses were performed. The seismic potential of active faults in the region was calculated using the formulas of Zare (1995), Ashjaei and Vorozi (1978), and Wells and Coopersmith (1994). In addition, the spatial analysis method was used to analyse and determine the seismic risk. In this study, the method proposed by Barbarian et al. in spatial analysis was used. The steps of this method are as follows: first, faults with a length of more than 10 km are identified. Then, faults with a length of 5 to 10 km are identified and added to the first category of faults, and configuration operations are applied based on the distances to the source of the earthquake and the faults. Then, the extracted map is overlapped with the land use map to determine the location of human settlements in the danger zones of fault lines, and the map resulting from the sensitivity of the region's formations from the point of view of resistance, and finally the final map of earthquake danger configuration and the position of highly populated centres is obtained based on the level of risk-taking. Results and Discussion The most important factor in the structural development of Alborz is the existence of driven and inverted faults that are located along this mountain range. Astara fault is one of Alborz’s most important faults. This fault is one of the most important geological structures in the northwest of the country, and the occurrence of destructive historical earthquakes has increased its importance. In this regard, the activities of major and minor faults of this region and the resulting seismic potential were investigated and analysed in this study. In the present work, based on the analyses performed by remote sensing of satellite and GIS and the implementation of processes such as principal component analysis, band composition, Hillshid and filtering of satellite images indicating structures, there are definite line structures in the study area. In this regard, 25 fault lines were identified in the study area. The presence of fault lines in the study area indicates tectonic activities there. In fact, the fault lines extracted from the satellite image show different faults, especially in the north-eastern, north-western, western and south-eastern parts of the study area. Yamani and Alizadeh (2016) also achieved similar results in the study of tectonic activities of the Karaj watershed using satellite imagery and geomorphological indicators. Also, based on the results of the study, among the methods used to identify faults in the study area, the methods of applying directional filters, principal component analysis and Hilshid have had a great impact on the proper identification of faults. This can be due to the feature of edge highlighting in directional filters, and also the presence of more than 80% of the information in the first band of the principal component analysis. In addition, fault lines that were not identified by the above two methods were extracted using the Hillshid method. Based on the results of the used indicators, most of the basins have high tectonic activities in the study area, and the morphological characteristics of the studied catchments are under the influence of fault lines in the area. ConclusionThe results of the relatively active tectonic index showed that basins 1 and 2 in the eastern parts of the study area had the highest tectonic activities. In the present study, the calculations performed in GIS and Excel software were calculated using the equations provided by Norouzi and Ashjaei, Zare, and Wells and Coopersmith, and the average seismic power of Astara fault was equal to 6.9 Richter, Neur fault equal to 7 Richter, Hir fault equal to 6.2 Richter, and Sangour fault equal to 4.8 Richter. In general, the average seismic power for the main and secondary faults in the study area based on Nowruz and Ashjaei, Nowruzi, and Wells and Coopersmith equations was estimated to be 5.844, 5.710 and 6.517, respectively. Also, in addition to calculating the seismicity, spatial analysis method was used to determine the risk of faults. The results showed that most of the settlements in the study area are located at a distance of 3000 to 10,000 meters from the fault lines. The results indicate three hazardous zones in the study area. Shayan et al. (2013), in a similar study, determined the earthquake risk zones in the Garmsar alluvial fan using the GIS and concluded that most of the residential centres in their investigated study area are located at a distance of 3000 to 7000 meters from the fault lines.
Geomorphology
Masoumeh Rajabi; Shahram Roustaie; Seyed Mohammad Reza Javadi
Abstract
IntroductionLand subsidence is commonly referred to as vertical downward movements of the earth's surface that can be accompanied by a slight horizontal vector. Land subsidence is a global problem and a morphological phenomenon. This phenomenon is affected by human activities and natural factors that ...
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IntroductionLand subsidence is commonly referred to as vertical downward movements of the earth's surface that can be accompanied by a slight horizontal vector. Land subsidence is a global problem and a morphological phenomenon. This phenomenon is affected by human activities and natural factors that may become a threat to humans and human achievements. The phenomenon of subsidence, although imperceptible and gradual, but is associated with many risks, including the creation of potholes, failure and cracking of buildings, skewing of high facilities, damage to agricultural facilities, breakage and destruction of stairs Roads and network of urban thoroughfares. Therefore, this issue affects the urban areas more, which if not addressed can lead to many human and financial losses. Accordingly, monitoring the rate of land subsidence in order to reduce the negative effects as well as controlling its development process, will be very important and it is necessary to regularly estimate the area subsidence trend. Due to the importance of the issue, in recent years, various studies have been conducted in the field of subsidence and advances in the field of remote sensing have led to monitoring the phenomenon of subsidence, unlike in the past, with greater accuracy and speed. One of the methods that has received a lot of attention in recent years is the radar interference method, which has high accuracy and speed in processing information and monitoring land surface changes, so in this study, this method is used to monitor the situation. Subsidence of cities located in Hamedan-Bahar plain has been used.Materials and methodsIn this study, in accordance with the intended objectives of Sentinel 1 radar images (73 radar images during the period 16/01/2015 to 14/01/20120), the information of piezometric wells in the region (related to the Water and Regional Organization of Hamadan Province ) And the 30 m SRTM digital elevation model have been used as research data. Important research tools also include GMT (for radar interference measurement and SBAS time series) and ARCGIS (for mapping). This research has been done in 2 general stages. In the first stage, the amount of subsidence in the area is assessed using radar images. In order to perform this step, radar interferometry and SBAS time series method have been used. In the second stage, the annual drop in groundwater in the region is evaluated. At this stage, in order to assess the annual drop in groundwater in the region, information about 25 piezometric wells located in the study area in the period of 1375 to 1395 has been used.Discussion and resultsThe study of subsidence results in the study cities indicates that the average annual subsidence in the urban area of Hamedan was about 23 mm, the highest amount of which was related to the western regions of the city. The average annual subsidence in the urban area of Bahar was about 9 mm, the highest rate of subsidence was in the southern areas of the urban area. The average annual subsidence in the urban area of Salehabad with 6 mm was lower than other cities, but the average annual subsidence of Lalejin with 47 mm was the highest among cities. Also, in this research, information related to 25 piezometric wells (statistical periods of wells related to the years 1375 to 1695) located in the study area has been used. Examination of the level of water level drop in the studied wells indicates that these wells have faced a lot of water level drop, so the average annual drop of wells is calculated between 100 to 2070 mm. The study of the spatial status of groundwater depletion indicates that the middle areas of the study area have the highest average annual groundwater level depletion.ConclusionThe results obtained from the assessment of subsidence in the studied urban areas indicate that the highest amount of subsidence occurred in the urban area of Lalejin, so that this area during a period of 5 years (01/16/2015 to 01/14 /2020) had a subsidence between 26 and 234 mm (average annual 47 mm). In this study, the situation of groundwater resources decline has also been evaluated. The results show that the average annual drop of wells in the region is between 100 to 2070 mm, which is the highest rate of decline in the middle areas of the study area, and given that in this region, the highest rate of subsidence also occurred. Given that there is a significant relationship between land subsidence and groundwater level decline (correlation 0.7). In fact, a study of the subsidence of cities in relation to the decline of groundwater resources indicates that the city of Lalejin, due to its location in the middle of the area and the high annual rate of groundwater decline, had the highest rate of subsidence. Also, the results of evaluations have shown that in addition to the decrease of groundwater resources, constructions have also played a role in increasing the rate of subsidence, so that the city of Hamedan has faced less groundwater loss than the city of Bahar, but it had more subsidence. Considering that the highest rate of subsidence occurred in the western, southern and eastern regions of Hamedan urban area and these areas have faced a lot of physical development in recent years, so it can be said that in addition to water loss Underground, the development of construction has also played an important role in the rate of subsidence in this city.
Geomorphology
Mojgan Entezari; Hamide Gholamhaydari; Haji Karimi
Abstract
IntroductionMainly containing thin gypsum units, evaporite formations cover 8% of the Earth's surface and 25% of the Earth's continental surface (Ford and Williams, 2007). The term karst refers to a set of geological processes and the phenomena resulting from the dissolution of carbonate rocks. Decomposing ...
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IntroductionMainly containing thin gypsum units, evaporite formations cover 8% of the Earth's surface and 25% of the Earth's continental surface (Ford and Williams, 2007). The term karst refers to a set of geological processes and the phenomena resulting from the dissolution of carbonate rocks. Decomposing the structure of the rocks forms a unique hydrological regime, leading to the development of special landforms (Ministry of Power, TAMAB, 1994). In general, the eight elements needed to develop a karst are: precipitation, relief, lithology, thickness of carbonate layers, carbon, low temperature, pressure, and tectonic rocks (White, 1988). Sinkholes are the enclosed depressions that are known as the characteristic of carbonate and evaporite karst landscapes. In recent years, several genetic classifications have been published for sinkholes (Gutierrez et al., 2008).Materials and methodsTo conduct this research, a 160,000-m2 area of the Gachsaran formation in Maroon plain with a high density of sinkhole was examined and visited. The exact geographical location and specifications of 51 sinkholes were surveyed, and it was found that the sinkholes totally account for 25% of the surveyed area. Table 1 lists the specifications of the sinkholes. Also, in another field visit conducted in this study area, a sub-basin with an area of 6.2 hectares, average slope of 28%, and length of 2301.7 m was selected for the surface runoff sampling during the precipitation, which also included a number of previously surveyed sinkholes. The surface runoff samples taken included the first moment of runoff onset, which began 3 hours and 27 minutes after the start of precipitation. Then, 5:19, 5:45, 8:10, 9, and 9:20 after the start of precipitation, other samples of surface runoff were taken again to monitor the changes in the ions dissolved in the runoff in the spatial and temporal intervals. The minimum height of this sub-basin is 520 m, and its maximum height is 888 m above sea level. Also, in this regard, to estimate the average long-term rainfall of the region from the 20-year rainfall data of the meteorological stations in the study area, the daily rainfall data of the Maroon meteorological station in the vicinity of the study area, 1:100,000 geological map of Behbahan sheet, 1:50,000 topography, and 10-m DEM of the study area were used as the research data.Results and DiscussionThe obtained results showed that a total of 25% of the surveyed area is covered with the surface and visible sinkholes. It should also be noted that the dissolution in the Gachsaran formation is not the only erosion process that is taking place. In addition to the dissolution of gypsum, the marls of this formation are eroded by the surface runoff due to the precipitation and leave the basin as a suspended load, which accelerates the formation of sinkholes. Therefore, it can be stated that the time interval estimated in this study can be shorter, because the effect of the accelerating factor of the suspended load was not calculated, which requires the investigation and study to calculate the suspended load. Directing the runoff by sinkholes to downstream areas is likely to lead to the same expansion of the underground karst and tunnel, which is not visible. Also, it is not clear how many cavities and tunnels formed in the subsurface of this area, but this is not expected to be low based on the obtained results. There are roads, agricultural lands and, more importantly, residential areas on the gypsum zones, at least 25% of which are visible sinkholes, and the subsurface tunnels that are expanding every year at this dissolution rate. In addition to the effective rainfall, the presence of agricultural lands requiring continuous irrigation and intensifying the dissolution rate can lead to surface collapses and expansion of sinkholes, which ultimately threatens the life and financial security of the inhabitants in these areas.ConclusionBased on the field observations and the conducted studies, the sinkholes in the stream course have a generally elongated form and often have several ponors. Given that the sinkholes do not retain the aggregated runoff inside the sinkhole and the runoff exits through the same ponors, such diversity in the number of ponors results in a number of sinkholes in the stream course, which are connected together through a subsurface path. Unlike calcareous sinkholes that can direct the runoff current to karst aquifers, water is rapidly saturated due to the high solubility of gypsum. The dissolution is mainly limited to the opening area of the sinkhole, and less runoff finds the opportunity to expand the sinkhole in depth. It should be noted that based on the results, to increase the safety factor and reduce the risk of gypsum dissolution, it is necessary to monitor and study the subsurface area and to examine the subsurface cavities and tunnels that have formed so far. Finally, to reduce the risks of the dissolution rate, some arrangements such as sinkhole risk zoning should be made. This is because the cavities in the gypsum layers with the high dissolution rate can easily expand and prepare the conditions for the sudden collapse so that the whole plain suffers the collapse, incurring human and financial losses.
Geomorphology
shahram roostaei; Davod Mokhtari; Christineh Jananeh
Abstract
IntroductionSlope instabilities are one of the most distinctive types of geomorphic hazards that are exacerbated by human interference and threaten most of the human installations, especially mountainous highways and impose heavy costs on the government and local residents. Each year, slope instabilities ...
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IntroductionSlope instabilities are one of the most distinctive types of geomorphic hazards that are exacerbated by human interference and threaten most of the human installations, especially mountainous highways and impose heavy costs on the government and local residents. Each year, slope instabilities cause enormous economic damages to highway, railways, power transmission and communication lines, irrigation and watering canals, ore extraction, as well as oil and gas refining installations, infrastructures in cities, factories and industrial centers, dams, artificial and natural lakes, forests, pastures and natural resources, farms, residential areas and villages or threaten them. Nowadays, many instabilities are resulted by human intervention and manipulations. One of the effective human factors in instability occurrence is the construction of highway. Highway construction, especially in mountainous areas, increases the probability of occurrence of various types of instabilities, as it changes the natural balance of the slopes and causes deformations in the land. Each year, lots of casualties and financial losses are imposed by the occurrence of various types of instabilities in the slopes overlooking the highways, which also cause the destruction of many natural resources in the country. However, the construction of roads, highways and freeways is necessary and unavoidable in today’s life.The Tehran-North highway will be the route that connect the Iran’s capital Tehran with the southern shores of the Caspian Sea.Materials and methodsThis contribution aims to study slope instabilities along this highway using logistic regression method. In this regard, layers of 14 effective factors were identified, comprised of elevation classes, slope, aspect, geology, land use, precipitation, distance from fault, river and highway, normalized difference vegetation index (NDVI), climate, slope length (LS), stream power index (SPI) and topographic wetness index (TWI). Consequently, maps of the factors responsible for instabilities were prepared as separate layers in the GIS environment and transferred into the Idrisi software. The whole procedure included: (1) preparation of digital elevation model (DEM), river and fault layers based on the 1:25,000 topographic map of the area, as well as distance maps from rivers and faults, (2) creating slope and aspect maps from DEM, (3) preparation of land use and NDVI maps of the region based on unmatched classification of Landsat 8 image of OLI sensor, (4) preparation of geological map, (5) preparation of precipitation and climate layers based on the information obtained from the meteorological organization, (6) creating LS, SPI and TWI layers based on the DEM, (7) conversion of the distribution data of the regional instabilities using Landsat satellite and Google Earth images, (8) correlating the information layers with the regional instability map and calculating their density per unit area, and (9) performing the logistic regression model using Terrset software.Result and discussionResults obtained by applying logistic regression model showed that the most important factors affecting slope instabilities in the Tehran-Soleghan highway area are distance from fault and climate. 27.14% of the Soleghan highway area possesses medium to high potential for instabilities, within which 86.26% of the instabilities have occurred. Furthermore, 4.57% of the Soleghan highway area shows very high risk in terms of instability occurrence, encompassing 61% of the occurred instabilities. According to the prepared maps, the middle and southern parts and a small section in the north of the Tehran-Soleghan highway area have the highest potential for instability occurrence. The high value of the ROC index and its proximity to the end value of 1 indicates that instabilities strongly correlate with the probability values derived from the logistic regression model. Additionally, the assessment of the instability potential map by the SCAI index showed that there is a high correlation between the prepared risk maps and the occurred instabilities, which have been confirmed by field surveys. The obtained results are in a good agreement with the general opinion that SCAI decreases especially in high and very high risk classes and indicates a high correlation between the prepared risk maps and the occurred instabilities and field surveys in study areas.ConclusionFinally, it can be mentioned that the logistic regression model is suitable for preparing the zonation of the probability of instability occurrence along the edges of the studied highway. As a final conclusion, it can be concluded that in addition to natural factors, the- human-made factors and particularly unsystematic highway construction can play an important role in the instability occurrences on the slopes overlooking the highway and in order to reduce the relative risks and increase the stability of the slopes, it is necessary to avoid manipulating the ecosystem and changing the current land use as much as possible, in addition to policy making for constructions in accordance with geomorphological and geological features of the area.
Geomorphology
Masoumeh Rajabi; Shahram Roostaei; Mohsen Barzkar
Abstract
IntroductionThe concept of morphometry involves the measurement and numerical analysis of land surface, shape, dimensions and form of land. In relation to flooding, watershed morphometry includes quantitative indicators describing watershed physical characteristics that control the pattern and quantitative ...
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IntroductionThe concept of morphometry involves the measurement and numerical analysis of land surface, shape, dimensions and form of land. In relation to flooding, watershed morphometry includes quantitative indicators describing watershed physical characteristics that control the pattern and quantitative characteristics of floods such as amount, time of occurrence, delay time, and flow hydrograph. Unusual development of cities due to population growth and consequent land use change has caused disruption of hydrological balance and increased flooding of basins. The purpose of this study was to prioritize the sub-catchments of Zab River based on a novel combination of morphometric analysis and statistical correlation and zoning of flood potential under sub-catchments.Data and Methodto disregard for human and social sub-basins, which has a great impact on the hydrological processes of the catchment. Based on the validation results, the Shinabad and Sufian basins have the highest priority, and the new method of morphometric analysis and statistical correlation have considered them the highest priority for managers' attention.The elongation ratio helps to understand the hydrological characteristics of the drainage basin and ranges from 1 for circular basins to 0 for extended basins and its high values indicate the shape of the basin circle, high peak discharge and high flood potential. Is. The values of tensile strength in all sub basins are more than 0.5 and indicate high potential for flooding. Straller (1964) considers the circle ratio a quantitative measure for visualizing the shape of the basin. High values of this parameter indicate circular shape, high to medium ruggedness and low permeability in the basin, which causes peak discharge in less time. The ratio of the circular ratios under the Lavin Tea Basins is 0.17, Copar 0.19, and Zab Small 0.27, indicating relatively low flooding potential in this parameter. The amount of this parameter is 0.35 under Shinabad basin and 0.31 under Sufian basin which indicates their higher flood potential in this parameter (Table 7). The branching ratio is an important parameter affecting peak runoff hydrograph discharge with high values indicating high instantaneous discharge and flood event. The mountainous and steep areas have a split ratio of 3 to 4. Branching ratio values indicate low flooding potential except for Shinabad basin which shows this ratio of 6.19 and this ratio indicates high flood potential Results and DiscussionSince hydrological units are based on morphometric parameters to prioritize flood mapping, firstly, using channel networks and elevation curves, topographic maps of 1: 50000 and digital elevation data are analyzed. The boundaries of the hydrological units became. Then, because the catchment morphological parameters have different effects on soil erosion processes and runoff formation, prioritization of the sub-basins was done in a new way based on the difference of morphological parameters and statistical correlation analysis between them. Morphometric parameters were calculated for all sub-basins in GIS software. Then, statistical correlation of morphometric parameters was performed based on the t-Kendall method using SPSS software. Based on the correlation matrix we can analyze the relationship between the parameters and define the relative weight for each parameter without All twelve variables including circular elongation ratio, branching ratio, flow frequency, drainage density, drainage texture, compaction index, shape factor, mean slope, roughness ratio, roughness, and roughness number for all sub-basins are calculated in Table 2. The Kendall correlation coefficient was used to investigate the relationship between Validation results showed that the new method of morphometric analysis and statistical correlation did not perform well in prioritizing all sub-basins, but this method was accurate in identifying the most priority sub-basins (most acute conditions). The reason for this may be due to the lower performance of morphometric analysis and the characterization of waterways in low-slope catchments. Also, the precise reason for not estimating the priority of some sub-basins is due.ConclusionThe selected twelve parameters are directly related to runoff and flood potential. Therefore, high values of parameters have a direct relationship with runoff and flood potential due to their greater impact on the selected twelve parameters. Indicator (Cv) values for each sub-basin are obtained from averaging of 12 indices and accordingly sub-basins of Shinabad and Sufis with high flood potential, sub-basin with small potential and sub-basin zab basin. Copar and Lavin Tea have physiographic and morphometric characteristics of the sub-catchments have a great influence on flooding and hydrological behavior, it is possible to study the status and potential of flooding below the catchments. In this research, in order to potential of flooding, firstly, Zab sub-basins were prioritized based on the new method of morphometric analysis and statistical correlation. Based on this method, the results showed that the Shin abad and Sufi basins are the top priority for the implementation of management measures to ensure.
Geomorphology
Mousa Abedini; Elhameh Ebady; Ehsan Ghale
Abstract
Introduction Landslides are one of the major geological problems around the world that cause compaction of subsurface layers. The cause of this phenomenon can be attributed to human activities such as uncontrolled abstraction of groundwater and natural activities such as earthquakes. Landslides ...
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Introduction Landslides are one of the major geological problems around the world that cause compaction of subsurface layers. The cause of this phenomenon can be attributed to human activities such as uncontrolled abstraction of groundwater and natural activities such as earthquakes. Landslides are also one of the main geological hazards in the region, causing serious damage to buildings, roads, infrastructure and bridges. According to the US Geological Survey, subsidence involves the collapse or subsidence of the earth's surface, which can have a small displacement vector. Therefore, identifying and monitoring the subsidence phenomenon is one of the most important and vital issues to maintain stability in the regions. For this purpose, researchers use various methods to study and observe this phenomenon, which are divided into three categories based on the position of the tools used: Subsurface methods, Ground Based methods and Remote Sensing methods. One of the most important of these methods is remote sensing, which collects data from the air or space using satellites, airplanes, or unmanned vehicles and balloons. Radar interference or InSAR, as one of the methods of processing radar images in active remote sensing, is one of the most accurate and economical methods that allows the detection and detection of differences in altitudes created in the shortest time and for large areas. Data and Method The study area is located in western Iran and one of the parts of Kermanshah city located in Kermanshah province is located in the area between latitudes 42 degrees and 9 minutes north and longitude 36 degrees and 2 minutes east. Radar interferometry studies in this study were taken by sentinel 1 satellite imagery of the C band. In this study, data from Sentinel 1 satellite in C-band were used. Using image processing with SARSCAPE 5.2 plugin in ENVI 5.3 software platform and using interferometry method, areas exposed to subsidence and the amount of subsidence in each area were determined. In the present study, the relationship between groundwater level drop and subsidence of Mahidasht plain has been investigated. For this purpose, groundwater depth data of 31 piezometer wells in Mahidasht plain were used. In terms of time, considering the accurate and available statistics, the statistics of 1394 and 1398 were cited. The steps of the research were as follows: after preparing the statistics of piezometric wells, the data reconstruction method was used to eliminate the deficiencies in the study data. The reconstruction method used, which was used only to correct the defects in the data, is the interpolation method, which was performed by Neural Power software (based on artificial neural network). To normalize the data, logarithmic transformations were used in SPSS 16 software and GS+ software was used for geostatistical analysis. Results and Discussion Examination of subsidence status during the study years shows that from 2015 to 2020, the rate of subsidence has increased. In Figure 1, the areas marked in red have the highest subsidence, the areas marked in green and yellow have the least subsidence, and the areas marked in black have no subsidence. According to the subsidence map of the region, the maximum average subsidence rate in the study area reaches 16 cm. According to the extracted subsidence map of the study area, it is observed that the highest amount of subsidence occurred in the eastern part of Mahidasht plain, which decreased to the west of the plain, so that in the western and south western part of the plain, the lowest Subsidence is observed. Relationship between groundwater extraction and land subsidence phenomenon Considering that groundwater abstraction is one of the important causes of subsidence in Mahidasht plain, in order to explain the trend of groundwater level changes, the general trend of annual water level of all wells were examined. According to the groundwater level interpolation map, the groundwater depth in Mahidasht plain varies from a maximum of 21.62 meters in 1994 to a maximum of 24.71 meters in 1998. ConclusionLand subsidence is a pervasive phenomenon in the world, which has had a significant quantitative and qualitative manifestation in recent decades, mainly due to the improper exploitation of groundwater resources and the intensification of its decline. In the present study, the relationship between groundwater level drop and subsidence of Mahidasht plain has been investigated. Examination of statistics related to the depth of study wells as well as groundwater level zoning maps confirm the decrease of groundwater level. In fact, over-harvesting and lack of balance between feeding the aquifers and draining them has caused the water table in the region to follow a continuous downward trend, with the emptying of water in the cavities of the aquifer and the displacement of water in these cavities with Air reduces the equilibrium pressure between the layers. Due to the disturbance of the balance between the pressure and the weight of the upper layers, due to the force of the weight of the upper layers, the aqueous layers are compressed and the water table decreases and because this decrease has a direct relationship with subsidence. Therefore, in order to deal with this environmental problem, it is recommended to prevent the development of subsidence in the region or to minimize the occurrence of this phenomenon as much as possible by managing land use in the area of subsidence and also adequate supervision over the extraction of underground resources.
Geomorphology
Imanali Belvasi; sayyad asghari; Fariba Esfandiari Dorabad; Batool Zeynali
Abstract
Introduction
Morphological Assessment will be necessary to understand the current situation and the potential for possible river changes in the future. Natural factors such as floods, soil erosion, landslides and human factors such as land use change and sand removal from the riverbed affect the morphology. ...
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Introduction
Morphological Assessment will be necessary to understand the current situation and the potential for possible river changes in the future. Natural factors such as floods, soil erosion, landslides and human factors such as land use change and sand removal from the riverbed affect the morphology. River systems have always been of interest to humans as one of the most vital elements of the Earth's surface. Humans also change the face of the earth by changing their use, destroying natural resources, plowing the land in the direction of the slope, planting trees in the riverbeds. Any Manipulation into the riverbed will change the process of erosion and sedimentation along the river. Understanding the characteristics of flow and sediment is the basis for evaluating the behavior of rivers and deciding on engineering activities. Therefore, it is necessary to obtain the necessary information on how they work before starting engineering projects for rivers.
Data and Method
In this study, geological maps at a scale of 1: 100000 of the Geological Organization, topographic maps at a scale of 1: 50,000 digits of the Geographical Organization of the Armed Forces, Landsat satellite images, 2020 April, November 1995, Climatic data Temperature and precipitation (1399-1374) of Lorestan Meteorological Organization and Digital elevation model of 30 meters has been used. Arc GIS software was used for spatial analysis and ENVI software was used for processing satellite images. The normalized water difference index is the first index of water extraction in images and remote sensing data. In this indicator, two green and infrared bands are used. Positive values of this index indicate water and negative values indicate phenomena other than water. Researchers have proposed different methods for studying changes in river channels. The transect method is used to evaluate changes and displacements in river channels. In this method, lines with specific distances on both sides of the river route are drawn as baselines. These lines are constant for the time periods studied. River channel displacements relative to these lines are quantified. To further evaluate the Kahman River canal, the canal migration rate method was used. The Kahman river Canal was divided into two areas, mountainous areas and plain and agricultural areas, based on topography and land use.
Results and Discussion
To calculate the area to the right and left of the transects, the Kahman river channel was cut separately with a transect layer in 1995 and 2020. Calculation of changes in the area of transects shows that about 185.85 hectares of land adjacent to the Kahman river (1995-1999) have been eroded. On average, about 7.43 hectares of these lands have been destroyed annually. The maximum value of this index in transect 30 is calculated at 8.27 hectares. In order to better understand the changes and dynamics of the Kahman river Canal, the migration rate index (Rm) was also used. First, two fixed lines were drawn around the Kahman river channel. The area between the two was calculated using Arc GIS software functions. The average migration rate of Kahman river (1399-1374) was 2.51 meters per year. The lowest level of this index occurred in Trasket 49 at 0.18 meters per year. The mountain factor and stabilization operations along the river have been the most important reasons for its control and stabilization. The highest rate of migration occurred in transects 4, 32 and 30 at 4.80, 5.5 and 6.12, respectively. Shortcuts and land use changes have been the main reasons for the high rate of duct migration in these transects. The largest amount of lateral changes in the Kahman river route occurred in parts of the plain and agricultural areas, including transects 30 to 35. The most important factor was the high lateral changes of the Kahman river route in the plain area due to the high erosion of the coastal and floodplain materials. Most of the constituents of the bed and banks of the Kahman river in these periods are from fine to coarse sands.
Conclusion
Duct migration rate index showed that the average displacement of Kahman river canal (1374-1399) was 2.51 meters per year. The lowest value of this index was 0.18 meters per year and the maximum value was 6.12 meters per year. Calculation of changes in the area of transects showed that about 185.85 hectares of land adjacent to the Kahman River (1374-1399) has been destroyed. On average, about 7.43 hectares of these lands are lost every year. In the mountainous area, the effects of the mountains were the most important factor in determining the morphological changes of the Kahman River channel. The presence of erodible materials along the Kahman River in the plains and agricultural areas has increased the lateral migration of meanders and the width of the valley and floodplains adjacent to the river has increased significantly. Therefore, it can be said that the Kahman River has had more geometric changes in the plains and agricultural lands.
Geomorphology
Mousa Abedini; biuk fathalizadeh; Masomeh Rajabi
Abstract
Introduction
When a natural process threatens human life or property, it is called natural hazard. Disasters’ statistics have shown that their effects are, considerably, increasing all over the world. Most of such disasters originate from geomorphological events. In fact, natural disasters have ...
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Introduction
When a natural process threatens human life or property, it is called natural hazard. Disasters’ statistics have shown that their effects are, considerably, increasing all over the world. Most of such disasters originate from geomorphological events. In fact, natural disasters have been a global concern and most of them have mainly been geomorphological. Hence, developing countries, in particular, are deeply influenced by such disasters. One way of decreasing damages caused by natural disasters is identification of disaster-prone areas and prevention of their development in such areas relying on land use planning. In this research, geomorphological hazards of flood, landslide and neotectonics were investigated in Zonouzchay catchment. The catchment in an area of 323 square km has been located in political-administrative zone of Marand county.
Methodology
The aim of the present study is to evaluate geomorphological hazards in Zonouzchay catchment through preparing zoning maps of flood, landslide and neotectonics hazards. Digital evaluation model images of height (DEM), geological maps and sentinel satellite images are the most important data used in the present study. For preparation of flood and landslide hazards’ map in Zonouzchay catchment, ten variables and effective parameters on flooding and flood spreading were combined in GIS environment. These variables are considered for zoning flooding hazard factors such as height, slope, convexity of the land surface, valley depth, lithological units, drainage density, distance from the main streams, height of the runoff, use and vegetation. For zoning landslide occurrence risk, the above mentioned variables (except for stream height, drainage density and valley depth) were used along with the three variables of distance from fault, slope direction and rainfall. ANP model in GIS was used in order to combine effective variables on flooding risk and landslide in Zonouzchay catchment. Moreover, zoning relative neotecnic activities for the underlying area was conducted by using relative tectonic activity index (Al Hamdouni, et al, 2008). Relative tectonics activity index (Iat) is developed by combination of other indexes. The index classifies the perspectives in four classes of relative tectonic activities:
Class 1: too high tectonic activities with values 1 < S/n < 1.5
Class 2: high tectonic activities with values 1.5 < S/n < 2
Class 3: medium tectonic activities with values 2 < S/n < 2
Class 4: low tectonic activities with values S/n < 2.5
Results and Discussion
Zoning Relative Tectonic Activity
Results of Iat index-basedzoning indicate that neotectonic activities in Zonouzchay catchment are, generally, medium to relatively weak. Field observations also indicate that erosive processes (in spite of resistant formations) are predominate in the study area. Lack or rare dispersion of neotectonic landforms, retreat and destruction of mountain fronts and widening of the valleys are among the reasons, which show relative weakness of the active tectonic in Zonouzchay catchment. The main part of the morpho-tectonic landforms of the catchment is in line with Zonouz-Harzand fault. For most of the sub-catchments Iat values are in classes 3,4, which shows average to weak status of the relative active tectonic in the catchment.
Zoning Flood Event Risk
ANP model-based results indicate that from among the employed variables, slope, distance from river and land surface convexity are, relatively, the most important variables with coefficients 0.23, 0.19 and 0.16. Findings of the study indicate that about 4% of Zonouzchay catchment area is in too high risk class, 7.4% in high risk class, 8.3% in medium risk, 21.7% in too low risk class and 58.6% is in too low risk class. Almost all upstream parts of the study catchment are in low risk to high risk classes. In the middle parts of the study catchment, flood zones are mostly bounded to two main valleys of the catchment. Width of the valleys has increased in different periods and, consequently, flood plains have been formed in the basin of such valleys. Some parts of Miyab and New Harzand villages have been located in this geomorphologic position. In the downstream parts of the catchment, width of Zonouzchay has increased considerably and also the two main streams of the study catchment join each other in this part. Presence of low slope lands, low relative height, adjacency to the main rivers, lower values of convexity index, higher density of drainage and the valley depth are considered as the most important effective factors of this part of the catchment in terms of flood event.
Landslide Risk Zoning
According to the results of ANP model, the three variables of slope with coefficient of 0.24, lithology with coefficient of 0.22 and rainfall with coefficient of 0.16 have the key influence on landslide occurrence in the study area. Hence, about 16.6 % of the catchment area is in too low risk class, about 38.1% is in low risk class, about 23% is in medium risk class, 15.8% is in high risk class and finally 6.5% is in too high risk class. Spatial distribution of the risk classes indicates concentration of high risk and too high risk classes in the middle arts of the study catchment. This can be related to various factors. Maybe, the most important reason is related to presence of geological formations prone to landslide and appropriate slopes for occurrence of such geomorphological process. In fact, in the middle parts of the study area dominance of slope 10%-40% , presence of high alluvial terraces , also occurrence of Marens , conglomerate formulations with Maren interlayers and dispersion of Flysch type have provided appropriate conditions for landslide.
Conclusion
Results of geomorphological indexes indicate that considerable part of anomalies of this index are originated from lithological differences of the area. Moreover, active tectonic zoning of the area shows relative weakness of neotectonic processes and movement of the area’s faults along with dominance of erosive processes. Regarding flood occurrence risk, results of ANP model indicated that the variables of slope, distance from river and convexity of the land surface have higher importance in flooding. From flooding occurrence perspective, about 4% of Zonouzchay catchment is in too high risk class and 7.4% is in high risk class. The dangerous zones are accordant to valleys’ bed of the two main streams of the catchment and hence, some parts of the residents in these valleys are exposed to destructive floods. Finally, based on results of ANP model results, three variables of slope, lithology and rainfall have higher importance in probability of landslide occurrence in the study area. About 16% of Zonouzchay catchment is in high risk class, and 7% of it is in too high risk class of landslide. Landslide occurrence in the middle parts of the catchment is highly expected due to a set of conditions such as vulnerable slope and geological formations.
Geomorphology
Mohammad Hossein Rezaei Moghaddam; Davod Mokhtari; Majid shafieimehr
Abstract
Introduction
Proper management of catchments is one of the most important ways to make optimal use of water and soil resources. In our country, most of the catchments, especially the mountainous catchments, do not have enough hydrometric and sedimentation stations. This fact makes any development and ...
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Introduction
Proper management of catchments is one of the most important ways to make optimal use of water and soil resources. In our country, most of the catchments, especially the mountainous catchments, do not have enough hydrometric and sedimentation stations. This fact makes any development and management plans difficult. Hydrologists and water resources researchers have come up with various solutions but none of them have been completely successful (Roustamiyan et al., 1999; 588 & Shaygan et al., 2011; 2). On the other hand, the limited methods of measurement in hydrology and the need to have a method to generalize the available statistics to areas without statistics or places where measurement is not possible. Also, simulating future hydrological changes is one of the main reasons for hydrological simulation (Beven & Binley, 2001; 46). The ability of the SWAT model to simulate the complex hydrological processes of watersheds in the GIS environment distinguishes this model from integrated models in which larger user units are the basis of operation.
Data and Method
The study area is part of the Qizil Üzan River. Shahar Chai basin along with other rivers such as Zanjan Chai, Aydughmush, and Qaranquchay is one of the sub-branches of Qizil Üzan that flows northwest and north of the basin and joins near the Myaneh city. The data used in this study include a digital elevation model of 1: 10000 of mapping organization, land use, soil, precipitation, minimum and maximum temperature, wind speed, solar radiation, relative daily humidity of synoptic stations, Sarab, Heris, Bostan Abad, Charoymaq and Runoff and the sediment of Shahar Chai station. In the watershed of Shahar Chai, a soil map prepared by natural resources of East Azerbaijan province has been used. Based on these maps, 21 soil texture classes can be distinguished in the whole basin. Also, based on the land use map, six land use classes in the area were identified.
Results and Discussion
After parameterization and data entry, the simulation was performed for 20 years from January 1, 2000, to December 31, 2019, based on a monthly time step. To determine the degree of sensitivity of flow parameters in the SWAT model, sensitivity analysis was performed using the SUFI-2 method for 25 selected runoff parameters and 15 selected sedimentation parameters. Using validation results to remove parameters that are less sensitive from the calibration process, it is decided that finally the parameters with lower sensitivity were removed and 13 parameters for runoff and 7 parameters for sediment were selected that were more sensitive. The calibration model for runoff and sediment was done in one step with 1500 simulations in three replications. The calibration process ends when, based on the objective function, the coefficients required for evaluation are acceptable. According to the obtained results, all the evaluation criteria of the model in the simulation of runoff and sediment are allowed.
Conclusion
Examination of the results of the SUFI-2 method in the Shahar Chai basin showed that, based on the evaluation criteria of the coefficients of determination and Nash-Sutcliffe, both in the calibration and validation stages, it has good results in this basin. But they can't predict peak discharge and sediments well. To better determine the performance of the model, first of all, it is recommended that the statistics of stations and numerous and daily runoff and sedimentation measurements should be used instead of monthly, if any, in a basin, to compare their results. Secondly, to achieve the desired results, this model should be used in comparison with other simulation models in this basin and adjacent basins.
Geomorphology
najmeh shafiei; LAILA GOLIMKOTARI; Aboalghasem Amir Ahmadi; Rahman Zandi
Abstract
Introduction
Today, the phenomenon of land subsidence is one of the most important geomorphological hazards on a global scale, which causes great damage to urban and rural structures, development facilities. Most of the reports from around the world related to the phenomenon of land subsidence have ...
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Introduction
Today, the phenomenon of land subsidence is one of the most important geomorphological hazards on a global scale, which causes great damage to urban and rural structures, development facilities. Most of the reports from around the world related to the phenomenon of land subsidence have been related to arid and low rainfall areas. According to the US Geological Survey, a subsidence phenomenon involves a collapse or subsidence that can have a small displacement vector. Land subsidence is a geological phenomenon that causes the earth's surface to descend slowly and horizontally.
In recent decades, most joints and fissures in agricultural areas have been reported due to over-abstraction of groundwater. Recently, urban areas have also been affected by this phenomenon. These seams and cracks cause a lot of annual damage to ground-level installations such as roads and bridges, buildings, power transmission lines, oil and gas transmission pipes, water pipes and sewage systems, wells wall pipes of exploitation wells. In addition, they provide a path for surface pollutants to move to groundwater sources and contaminate groundwater by infiltrating aquifers.
Among the innovations of this study, for the first time, radar interferometry technique was used to investigate the risk of subsidence of Nurabad plain aquifer subsidence. , Identification of vulnerable areas in the aquifer area.
Methodology
The method used in this research is applied analysis. Groundwater data including piezometer and exploitation wells were used to investigate groundwater level changes and Sentinel 1 images were used to calculate radar interferometry. Geographic weighted regression model (GWR) was used to investigate the relationship between subsidence and groundwater loss parameters.
By examining the changes in groundwater level of piezometer wells in the aquifer during a period of 17 years (1380-1397) showed that an average of 15 meters of groundwater drop has occurred in the plain. This decrease in agricultural and residential areas is a priority compared to other uses. By preparing the output of radar images during 4 statistical years, the results show that in 2015 the maximum amount of leakage was 7 cm and in 2016 it increased to 8 cm. In 2017 it is equal to 9 cm and in 2018 it is equal to 10 cm. In the end, by calculating the average of these four years, the amount of subsidence at the aquifer level increases significantly, with the regions in the central and eastern parts of the aquifer having the highest subsidence at the aquifer level. Which has been developed in residential and agricultural areas of the region so that the effects and evidence of these meetings are visible in residential houses and agricultural lands according to Table (2) in the analysis section to examine the status of subsidence rates in the study area using Radar images were taken during the mentioned years and show that in 2015 it is equal to 8 square kilometers, which is compared to 2014, in 2016 it is equal to 34 square kilometers, and in 2017 and 2018 it is equal to 40 and 86 square kilometers. According to the maps, we see in these 4 consecutive years that every year b The amount of subsidence at the plain level has increased and thus subsidence at the plain level has become a kind of hazard.
Results and discussion
High values of R2 have occurred in the central parts of the model aquifer, which shows a good estimate of the model in estimating the dependent variable and the predictive explanatory variable. Also, relatively lower values are located in the southern parts of the aquifer by examining the subsidence status in the plain. By creating a relationship with the groundwater drop layer, it showed that the observed values with the predicted values indicate a strong relationship. The layer shows the coefficient of determination R2, which is the highest coefficient of R2 in the central part, which is about -0.79 Is 0.53 Figure (7). The distribution of the remaining space of the GWR model errors shows that the model outputs are closer to the actual values. Second, the resulting map shows the low error values in the range.
Occlusion
The average subsidence rate is about 4 cm per year and the average 4-year average is 16 cm. The average area of the aquifer where the subsidence has taken place during 4 years is about 36 square kilometers, which includes about 5% of its area. The high concentration of wells and the greatest drop in groundwater and the concentration of existing cities and villages. In these areas, due to the water needs of the residential community, including the city of Nurabad and surrounding areas, as well as the water needs of the industrial sector, including factories and agricultural activities, access to water resources is more and groundwater extraction is very high. There has been a high decline that these factors with the intervention of the arid climate of this region has caused the high talent of these areas in the discussion of subsidence and has been identified as one of the critical areas of the city in the subsidence map. The results of radar interferometry show that uncontrolled extraction from the surface of underground reserves has caused the subsidence of the central part of the aquifer and also the presence of several aqueducts at the aquifer has caused damage to residential centers. One of the areas with the highest risk of subsidence in the plain, in the eastern, central and southern parts, the rate of groundwater loss in the aquifer within 14 statistical years is about 22 meters in the same well and the results of GWR method show local R2 in the central parts of the aquifer which is about 79% maximum and shows a high correlation between subsidence and groundwater loss Residual rate in the central part which is equal to 0.007 / 0007 which is a high coefficient of significance.
