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), ...
Read More
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
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 ...
Read More
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
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 ...
Read More
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
Ahad Ranjbari; Mousa Abedini; Davod Mokhtari; Khalil Valizadeh Kamran
Abstract
Introduction
Similar to other parts of Iran, Azerbaijan Plateau is active tectonically due to the Eurasia-Arabia cluster convergence, and its hydrogeomorphological impacts are evident as a strike-slip fault, folding, horst, graben, changes in the topography, and drainage system (Abedini, 2016: 75). ...
Read More
Introduction
Similar to other parts of Iran, Azerbaijan Plateau is active tectonically due to the Eurasia-Arabia cluster convergence, and its hydrogeomorphological impacts are evident as a strike-slip fault, folding, horst, graben, changes in the topography, and drainage system (Abedini, 2016: 75). Therefore, investigating and understanding the function of faults can significantly contribute to analyzing the tectonic activities, the occurrence of earthquakes, their geomorphic hazards as well as the environmental planning and management, the adaptation of the land use, and constructions regarding the tectonic situation of the regions and reduce their hazards.
The current research aims to identify the geomorphic hazards caused by the tectonic activities, especially the behavior of faults, for the planning and management before the occurrence of hazards and their resulted crises. In this regard, the principal purpose of this research is to study and identify the faults of the Qoshadagh fault zone and their geomorphic impacts in the northwest of Iran and a part of the structural block of Aras Fault Zone (Berberian & Yeats, 1999).
Data and Methodology
Three methods of manual, automatic, and mixture were used to precisely extract the region's faults, affected by the doublet seismic activities of 12 August 2012 with the magnitude of 6.4 and 6.2 Richter that had only 6 kilometers and 11-minute distance from each other (Donner et al., 2015). Moreover, survey study and manual measurement of the replacements were used. Hence, Envi 5.1 software was used to apply the techniques and process of images. Also, PCA Geometrica was used to automatically extract the lineaments, and ArcMap 10.4.1 was applied to draw the output map. In the automatic method, Landsat 8 satellite image of OLI sensor with 33 rows and 168 paths was fused with its panchromatic band (15 meters). Then, the edge detection, thresholding, and extraction of fractures were conducted using algorithms. The map of lineaments was prepared using filtering, PCA, and RGB color model in the manual or visual method, and, was adapted using the automatic method. Images of Sentinel-B2 and Spot were also used due to some properties to ensure. Finally, the obtained lineaments were checked by the field data.
Discussion and Conclusion
After analyzing the automatic method results, applying the lineaments manually along with the field controls, the obtained result is displayed in an overlaying map. Then, by investigating the obtained lineaments and removing the repetitive and incompatible lineaments automatically, and consultant with the tectonics experts and geomorphologists familiar with the region, the lineaments with 80% possibility of being a fault were drawn in a final map of the region’s faults. It is evident that the extraction of the definite faults of the region requires different RS sources, such as radar data, GPS, gravimetric satellites, etc. Rose diagram was used to understand the length and direction of the faults. As a result, the length of the faults was more in 100-280 degree and 145-325 degree, and no-fault was extracted along the 80 degrees, although this length can be seen in the field observations. The results of the field study, overlaying some of the geomorphological effects, including the obstruction and deviation of the waterways, formation of the pressure ridges, and fault pools, have confirmed and improved the software outputs.
Results
Using purposive remote sensing along with the field studies can play a significant role in identifying the structural ruptures that are usually hardly visible and emphasize the spatial-temporal changes after the earthquake and its role in reducing the ground hazards (Yang et al., 2017). In this regard, the faults of the Qoshadagh zone were extracted using automatic, manual, and semi-automatic methods with satellite images. The obtained results were compared with the field study and adapted to the effects and fractures caused by the earthquake and the new faults were also identified. The obstruction and deviation of the waterways, fault edges, tension, and pressure ridges, etc., are the most significant evidence that contributed to extracting the fault lineaments using the satellite images. In the current study, the faults of the region were displayed as the fault system instead of single fault lineaments that were in line with the previous studies with a different purpose (Copley et al., 2012; Ghods et al., 2015). Also, the privilege extension of faults in western and eastern directions was identified. Using automatic and manual methods is not sufficient. Therefore, the mixture method was used to obtain better and more precise results. It is evident that the extraction of the definite faults of the region cannot be obtained only by having optical images and other RS resources are required, such as radar data, GPS, and gravimetric satellites (with a high spatial separation). Furthermore, the field control and survey and investigating the geomorphologic forms must be considered an inseparable part of these studies.
Geomorphology
musa abedini; shahram roostaei; Mohammad Hossein Fathi
Volume 22, Issue 66 , January 2019, , Pages 187-205
Abstract
Diagnosis and classification of landslides is a critical need in the risk analysis before and after the disaster. And primarily through land surveying or traditional interpretation of images was done. In this paper to identify and classify types of object-oriented approach landslide has been paid. The ...
Read More
Diagnosis and classification of landslides is a critical need in the risk analysis before and after the disaster. And primarily through land surveying or traditional interpretation of images was done. In this paper to identify and classify types of object-oriented approach landslide has been paid. The data used in this study consisted of false color images obtained from satellite data Resourcesat-1 with spatial resolution of 5.8 meters and digital elevation models with 2.5-meter resolution satellite image of 10 meters of Cartosat-1 was used. This method was used for the North West basin and then used without further reforms in the eastern part of the basin. A total of three sliding using this method accurately identified 71.11% and 91.4% classification accuracy has been detected. In this way, the landslide early detection of high accuracy and speed, hence has great potential to assist in risk analysis, disaster management and decision making process after the earthquake or heavy rainfall, can be used related entities, including crisis management headquarters, natural resources and watershed institutions.
All other Geographic fields of studies , Interdisciplinary
Mousa Abedini; Khalil Valizadehkamran; Nader Sarmasti
Abstract
Physical expansion of Tabriz metropolitan increases the possibility of earthquakes risks. Given the importance of this issue, this research is trying to pay to monitor the activities and seismic potential of Tabriz fault and the estimates of casualties in Tabriz metropolitan using remote sensing and ...
Read More
Physical expansion of Tabriz metropolitan increases the possibility of earthquakes risks. Given the importance of this issue, this research is trying to pay to monitor the activities and seismic potential of Tabriz fault and the estimates of casualties in Tabriz metropolitan using remote sensing and GIS techniques. To achieve this goal, ASTER satellite image was processed in ENVI 5.3 software. Fault seismic potential is determined with empirical models and average calculations were used as the basis for assessment. The casualties are determined in accordance with the terms of seismicity and structure of our country urban elements, respectively. Based on visual interpretation of satellite data, along Tabriz fault are exposed geomorphic changes that reflect the tectonic activity is in the range of Tabriz metropolitan. Tabriz fault evidences examples of diversion of watercourse Ajichai, cliffs and lens shape phenomenon are most important that have been considered in the interpretation of the activities on satellite images. Based on empirical models, be created in Tabriz fault earthquakes is average of magnitude 6.8 on the Richter scale. Assuming earthquake seismic activity according to Tabriz fault scenario, the total population of about 1605884 of the Tabriz metropolitan was estimated approximate number 1252589 casualties consist of 658412 people dead and 594177 people injury at night
Geomorphology
Musa Abedini; Bahareh Ghasemyan
Volume 19, Issue 52 , June 2015, , Pages 205-227
Abstract
Landslides and mountainside instabilities are major dangers for human activities which often cause the waste of economic resources and damage to properties and installations. These dangers occur in natural slopes or in slopes changed by man. This study mainly aims at identifying the factors influencing ...
Read More
Landslides and mountainside instabilities are major dangers for human activities which often cause the waste of economic resources and damage to properties and installations. These dangers occur in natural slopes or in slopes changed by man. This study mainly aims at identifying the factors influencing landslides happening in the city of Bijar, Kordestan Province, and at evaluating the regions having the potentiality of landslide for preparing localization map using the analytical hierarchy process (AHP) Model. In the present study, first employing field visits, questionnaires, geological and topographic maps, and reviewing the studies carried out, nine factors including the variables of: height from the sea level, degree of slope, direction of slope, geology, the distance from the linear elements (fault, road, river), rainfall, and land use were employed. Then affecting factors were binary compared using analytical method by indicating the weight of each factor as indicator for their effects in occurrence of landslide. Accordingly, the landslide zonation hazard map was prepared to the use of weighed information layer and weighted coefficient of each factor. Results of this study show That slope factor of the relative weight of 0.307, and Landuse factor with the relative weight of 0.218 The most effective respectively And the relative weight of rainfall factor 0.019 the lowest impact on Landslides have on the city of Bijar. Thus, 75.489 % of the area of the region have faced very low-risk, 10.037% with low risk, 3.628% with average risk, 4.062% with high risk, and 6.784% with very high risk.
Mosa Abedini; Hasan Setayeshi Nesaz
Volume 18, Issue 49 , November 2014, , Pages 139-165
Abstract
Zoning of Landslide hazards is one of the ways that used to determine critical areas. Landslide zoning maps can also be utilized in environmental planning to reduce damage. In the present article, the AHP has been applied to the Gollojeh basin located in Zanjan province. The most important factors in ...
Read More
Zoning of Landslide hazards is one of the ways that used to determine critical areas. Landslide zoning maps can also be utilized in environmental planning to reduce damage. In the present article, the AHP has been applied to the Gollojeh basin located in Zanjan province. The most important factors in landslide occurrence in this study basin were identified as: geology formation, slope%, land use, height and distance from river, slope aspect, rainfall and faults. After layering and assigning weights to them the final map was produced in Arc GIS .The final results from this study show that the weight of the nine criteria respectively: are 0.4092, 0.2485, 0.1439, 0.0786, 0.0479, 0.0309, 0.023, 0.0181 with geology and faults having the greatest and last weights. Finally the landslide map denoting in four domains at very high risk, high risk, medium risk and low risk was prepaerd.
