Geological Environment and Engineering
Sayed Naeim Emami; Saleh Yousefi
Abstract
Mass movements are among the most dangerous natural hazards in mountainous regions. The present study employs machine learning (ML) models for mass movement susceptibility mapping (MMSM) in Iran based on a comprehensive dataset of 864 mass movements which include debris flow, landslide, and rockfall ...
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Mass movements are among the most dangerous natural hazards in mountainous regions. The present study employs machine learning (ML) models for mass movement susceptibility mapping (MMSM) in Iran based on a comprehensive dataset of 864 mass movements which include debris flow, landslide, and rockfall during the last 42 years (1977–2019) as well as 12 conditional factors. The results of validation stage show that RF (random forest) is the most viable model for mass movement susceptibility maps. In addition, MARS (multivariate adaptive regression splines), MDA (mixture discriminant additive), and BRT (boosted regression trees) models also provide relatively accurate results. Results of the AUC for validation of produced maps were 0.968, 0.845, 0.828, and 0.765 for RF, MARS, MDA, and BRT, respectively. Based on MMSM generated by RF model, 32% of study area is identified to be under high and very high susceptibility classes. Most of the endangered areas for mass movement are in the west and central parts of the Chaharmahal and Bakhtiari Province. In addition, our findings indicate that elevation, slope angle, distance from roads, and distance from faults are critical factors for mass movement. Our results provide a perspective view for decision makers to mitigate natural hazards.
Hydrology
Elham EbrahimZadeh; Ebrahim Rahimi; Vahid Gagheri
Abstract
Identifying landslide-prone areas provides a basis for slope-stabilization and mitigation programs. In Hablehroud watershed, artificial neural network and fuzzy logic (FL) as one of the methods of multicriteria-decision analysis based on ArcGIS were used in the scientific evaluation of landslide-prone ...
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Identifying landslide-prone areas provides a basis for slope-stabilization and mitigation programs. In Hablehroud watershed, artificial neural network and fuzzy logic (FL) as one of the methods of multicriteria-decision analysis based on ArcGIS were used in the scientific evaluation of landslide-prone areas. For this purpose, MATLAB, IDRISI and ArcGIS software were used. After preparing landslide-susceptibility maps, the prone zones predicted by FL and multilayer perceptron artificial neural network (MLP-ANN) were compared with the Hablehroud landslide database (distribution map). The results indicate a good overlap between the prone zones predicted by the MLP-ANN and landslide field observations. Finally, the performance of different methods in generating landslide-susceptibility maps were compared to each other using the validation indicators of "quality-sum index (Qs)" and "receiver-operating-characteristic curve (ROC)" to specify the optimal and applicable method for the landslide risk management of the Hablehroud watershed. By analyzing the obtained zoning maps and considering the Qs and "area-under curve (AUC)" values of different FL operators and MLP-ANN for the landslide-susceptibility maps, it is observed that the Qs (1.6299) and AUC (0.806–very good) values of the MLP-ANN are higher than those calculated for the sensitivity maps by different FL operators.
H. Baboli-moakher; K. Shirani; A. R. Taghian
Abstract
Catchments are natural systems in which natural phenomena like landslides are considered as natural disasters. As a chaos factor, they have a main role in forming unstable condition, tackling energy, accelerating erosion and generating sediment. So factors causing slope instability are reaction of the ...
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Catchments are natural systems in which natural phenomena like landslides are considered as natural disasters. As a chaos factor, they have a main role in forming unstable condition, tackling energy, accelerating erosion and generating sediment. So factors causing slope instability are reaction of the system to positive feedback. This study aims to employ theory of natural system chaos, in the form of Shannon entropy index, to find the factors causing landslide and its hazard zonation in Fahlian basin. First, input layers including geology, rainfall, slope, aspect, land use, distance to river, distance to fault, and elevation were digitized using GIS techniques. Then occurred landslides were detected using satellite images and field study. Landslide hazard zonation based on defined weights of each parameter was generated. In order to run model and study its accuracy, receiver or relative operating characteristic (ROC), was used with 70 and 30 per cent of data as training and test, respectively. Results show that slope and aspect have the maximum effect on landslide occurrence with ultimate weight of 0.662 and 0.308, respectively. Landslide susceptibility zonation map show that more than half of study area (56.97 percent) have very high to high susceptibility. Disaggregation of areas with SCAI method show the high accuracy of the model in detection of area with average, low and very low susceptibility. Frequency ratio of hazard classes deals with high accordingly, area under curve (AUC) of ROC was estimated 0.87 with 0.026 standard deviation which is known as very good accuracy of model.
A. H. Pasha; A. Sorbi; S. Behzadi
Abstract
Mass movements, especially landslides, are one of the natural hazards that to a large extent occur, are controlled, or are prevented by human. It is obvious that human interferences in nature regardless of stability conditions and its natural balance leads to physical reactions from the environment to ...
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Mass movements, especially landslides, are one of the natural hazards that to a large extent occur, are controlled, or are prevented by human. It is obvious that human interferences in nature regardless of stability conditions and its natural balance leads to physical reactions from the environment to return the sustainability and balance. Damages caused by the landslides, which have been growing in recent decades, have made humans to find appropriate solutions to reduce and control this phenomenon. Zonation of areas susceptible to landslide is one of the most widely used methods to avoid hazardous areas or applying controlling methods in hazardous areas. This research uses artificial neural network for zonation of landslide susceptibility in the Qazvin-Rasht quadrangle area. The studied area is one of the most susceptible areas for landslide event in terms of topography, climate, and geology, as the history of the area shows 338 recorded landslides. Fifteen variables studied in other researches as effective variables in occurrence of landslides were selected to investigate this area. By combining these variables and the map of existing landslides, value of each of the 15 variables was extracted for sliding points. In the next stage, a number of points (1000 points) were randomly selected from the area and values of these variables were extracted for them. Each of the two data sets was divided into two training (70%) and test (30%) categories. We combined each of the two training and test categories, and used their output for training and testing the network. The number of internal layers of the neural network was determined to be 9 layers based on trial and error method and calculation of the root mean square error value (RMSE = 0.4041). The constructed neural network is of feedforward networks type with back-propagation algorithm and its training algorithm is of Levenberg-Marquardt back-propagation training algorithm type. After training and testing the network and conducting necessary corrections on it, the constructed neural network was used to predict the sensitivity of landslides in studied area. We placed results of this prediction in a range from 0 to 1 and obtain the best zonation map of the landslide susceptibility by choosing a threshold. Final evaluation of the zonation map of landslide susceptibility in the Qazvin-Rasht quadrangle shows an error of approximately RMSE = 0.4164 and the constructed neural network identifies 298 out of 338 occurred landslides in the high-risk zone, indicating the accuracy of 88.1%.
E Ghanavati; A Karam; E Taghavi Moghdam
Abstract
Ground assessment to identify and map of susceptible land are as to slope movements especially landslides is of studies related to natural geographers, particularly geomorphologists. Determining and recognition of susceptive areas to sliding could prevent making loss as well as facilitating slope stability ...
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Ground assessment to identify and map of susceptible land are as to slope movements especially landslides is of studies related to natural geographers, particularly geomorphologists. Determining and recognition of susceptive areas to sliding could prevent making loss as well as facilitating slope stability operations. In this study, the variables such as slope, the aspect of slope, petrology, land use, rainfall, and distance from river, fault, and road were used to map the risk of landslide in the Taleghan watershed. After constructing and analyzing the information layers by means of Arc GIS Software, the fuzzy membership functions were used for weighting the layers. The standardized fuzzy layers were overlapped in GIS environment and the landslide risk mapping was produced by means of fuzzy logic operators. The results of this study indicated that gamma function 0.7 is more appropriate than other fuzzy operators. Based on the abovementioned gamma, 18.91% of the area was identified as the high-risk areas. Obviously, allocating these areas for housing, facilities, etc. increases financial and physical damages.
K Solaimani; J Zandi; M Habibnejad
Abstract
Over the last few decades, many studies have been resulted in landslide susceptibility maps using different techniques including the probability method (frequency ratio), the Analytical Hierarchy Process (AHP), bivariate, multivariate, logistic regression, fuzzy logic and artificial neural network (ANN). ...
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Over the last few decades, many studies have been resulted in landslide susceptibility maps using different techniques including the probability method (frequency ratio), the Analytical Hierarchy Process (AHP), bivariate, multivariate, logistic regression, fuzzy logic and artificial neural network (ANN). This study aimed to evaluate the susceptibility of the occurrence of landslides in the Vazroud watershed located in MazandaranProvince, north of Iran. The achieved results were based on three methods of frequency ratio model, statistical index (Wi) and weighting factor (Wf), which integrated to Geographical Information System (GIS) and remote sensing techniques. Vazroud as mountainous watershed morphologically is with increasing occurrence of landslides and it caused many failures of the mass movement, which seem continues now. In order to reduce the effects of this occurrence, it is necessary to scientifically assess the area where are susceptible to the landslide. For this reason, landslide susceptible areas were mapped and the landslide occurrence parameters were analyzed using three different methods. The results of these analyseswere confirmed using the relative operating characteristics curve (ROC). The validation process showed that the value for the area under the ROC curve for the Wf method was found to be 0.962, with an estimated standard error of 0.002 and is better in prediction than the other methods of frequency ratio and the statistical index (Wi) model.
K Shirani; A Seif; A Nasr
Abstract
Regarding their nature and their variety, and hazards that landslides have for humans life and properties, landslides have always been the center of attention and study by scientist from different fields of study such as: geology, engineering geology, geomorphologies, these phenomena are a complex activity ...
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Regarding their nature and their variety, and hazards that landslides have for humans life and properties, landslides have always been the center of attention and study by scientist from different fields of study such as: geology, engineering geology, geomorphologies, these phenomena are a complex activity and different factors and variables could be effective in this occurrence, numerous studies have been done to recognize the effective factors, classification, zooming and modeling. Accordingly, we have tried to study the landslides in Kahredan basin in northern part of Semirom, DenaMountain in Zagros zone suburban area in Esfahan province and provide a landslide hazard zonation map by using the statistical method and the hazard map which has the most accuracy and precision will be selected. So finally we specify the order of effective parameters in landslides. According, by selecting following six parameters: slope aspect, lithology, land use, rainfall and distance from drainage, we provided the distribution of landslides map by using following four methods.
Information value, linear regression, discriminate analysis and area density. The best landslide hazard zonation map has been statistical method of information value which is capable of using in planning and urban developments. Effective parameters in landslides according to their importance are, lithology, distance from drainage, land use, slope and rainfall.
K. Shirani; A. Seif
Abstract
The landslide hazard zonation was executed by different methods and many of these methods were based on special condition of the study area. This research, at first, Pishkuh region (fereyidonshahr administration) was selected with 77646 hectars area in west of Esfahan province. Then, landslide inventory ...
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The landslide hazard zonation was executed by different methods and many of these methods were based on special condition of the study area. This research, at first, Pishkuh region (fereyidonshahr administration) was selected with 77646 hectars area in west of Esfahan province. Then, landslide inventory map was obtained by using airial photos, satellite images (ETM+2002), geology maps and surveying of the field. Also, the 8 important factors are effective in occurrence of landslide including slope gradient, aspect, lithology, landuse, rainfall, and distance to fault, road and drainage were determined by using inspect of feild, literature review in similar regions of northern Karoon and Dez basins in scale of 1:50000. In order to increasing of precision, speed and facility of analysis, all of the attribute and spatial data were entered into ArcGIS software. After producing of information layers and weighting to effective factors by using inventory map, landslide hazard zonation was created by two bivariarte statistical methods including to Information value and Density area methods and the results were assessed. When the density ratios (Dr) Index (for the purpose of camparing between hazard classes) increase in each two method, then hazard rate will increase and the separation between hazard zone classes is acceptable and increasable. The quality sum (Qs) and precision (P) indices (in order to comparing of methods together) for Information value method are 0.65, 0.034 and for Density area method are 0.56, 0.028, respectively. It is clear that the information value is better than Density area in landslide hazard zonation.
S. Rasouli; Z. Eskandari; Y. A. Abedini
Abstract
In this work a new method for measuring landslide displacements using moiré technique is presented. A linear periodic pattern (carrier grating) is pasted on the surface of a wall that has a crack due to the landslide displacements. The crack has been opening in the last few years. Lines of the ...
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In this work a new method for measuring landslide displacements using moiré technique is presented. A linear periodic pattern (carrier grating) is pasted on the surface of a wall that has a crack due to the landslide displacements. The crack has been opening in the last few years. Lines of the carrier grating are in parallel with the line of the crack. A suitable imaging system takes the image of the carrier grating and superimposes it on a physical grating (probe grating). A moiré pattern is formed. The displacements continually distort the image grating and the moiré fringes greatly magnify the displacements. By processing the relative displacements of the moiré fringes on both sides of the crack in successive frames, one can measure the amount of crack opening through time with high accuracy. The implementation of the technique is straightforward; displacements can be magnified by more than a factor of ten in a comparatively simple and reliable way. The method is applied to study the landslide of the village of Gholghati in Zanjan Province in the summer and the fall of 2009. The total amount of crack opening during the mentioned time 4 mm was measured. In this work, the measurement precision of crack opining was about 0.04 mm.
A. Abbasnejad
Abstract
The huge and historical landslide of Jiroft, being about 53 Km2 in area, is located in 35 Km NW of Jiroft town just adjacent to Jiroft Dam and in coordinates of 28ْ 45َ to 28ْ 53َ N and 57ْ 20َ to 57ْ 30َ E. This slide which has taken place ...
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The huge and historical landslide of Jiroft, being about 53 Km2 in area, is located in 35 Km NW of Jiroft town just adjacent to Jiroft Dam and in coordinates of 28ْ 45َ to 28ْ 53َ N and 57ْ 20َ to 57ْ 30َ E. This slide which has taken place as a result of massive movement of upper reefal part of Qom formation dipping only 6ْ, 8 cubic kilometers in volume and about 300 meters thickness over the underlying marls, is recognizable based on shattered rocks, anomaly along the course of Halil Roud and the presence of well-rounded igneous boulders in some parts among the shattered rocks. As a result of this slide, the course of Halil was completely blocked and an ephemeral lake was created. Afterwards, the lake overflowed in another place (the present place of the Dam) which was the lowest point in its periphery. Due to this river detour, the Halil Roud incised its fan, created a gorge from the overflowing point to its confluence point, as well as incision of several small fans along its course. The presence of several active faults and low slope of the sliding mass imply the probable influence of earthquake and heavy precipitation as triggering mechanisms. The main characteristics of this slide include very low slope (6ْ ), its size (53km2 in area and maximum run- out distance of about 7 km), comprising four parts, specific mechanism (like other sturztorms) and its time of occurrence (probably 60000 to 100000 years ago). Depending on the classification of landslides, it may be considered as extremely rapid rock slide, sturzstorm, rock avalanche as well as debris avalanche. The desert varnish of boulders engaged in the slide mass and the solution runnels generated after the slide suggest that the age of the slide is about tens of thousands to several thousands years ago
H. Gharahi; B. Bohlooli; A. Sayyar; M. Shariat jafari
Abstract
Landslides cause damage to property and pose a threat even to human lives. Suitable landslide susceptibility, hazard and risk models could help mitigate or even avoid the unwanted consequences resulted from such hill slope mass movements. For the purpose of landslide susceptibility assessment, a spatial ...
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Landslides cause damage to property and pose a threat even to human lives. Suitable landslide susceptibility, hazard and risk models could help mitigate or even avoid the unwanted consequences resulted from such hill slope mass movements. For the purpose of landslide susceptibility assessment, a spatial database, which included 18 landslides prepared and analyzed using LISS-IV satellite imagery and geographical information system (GIS) technology. Analytical hierarchy process (AHP), the statistical index (Wi) and weighting factor (Wf) methods were applied to determine the significance of event-controlling parameters in triggering the landslides. The parameters included lithology, slope gradient, slope aspect, elevation, distance from faults, distance from stream and drainage density. These factors are different in geomorphic and geologic setting. The result showed that lithology, slope gradient and distance to stream play most important roles in landslide susceptibility. To confirm the practicality of the three susceptibility maps, there were compared with landslides activity map containing 12 active landslides. The results showed that the Wi method gave a more realistic picture of the actual distribution of landslide susceptibility, than the Wf method in the reservoir of Alborz dam.
M. Mohammady; H.R. Morady; S. Feiz nia; H.R. Pourghasemi
Abstract
Destruction and inordinate use of resources causes instability of natural slopes. Policymakers pay high attention to slopes instability investigation in order to supply zoning map to identify susceptible areas and stable location for the development of new settlements in the future. Iran especially in ...
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Destruction and inordinate use of resources causes instability of natural slopes. Policymakers pay high attention to slopes instability investigation in order to supply zoning map to identify susceptible areas and stable location for the development of new settlements in the future. Iran especially in the north and Haraz road is always exposed to landslides hazard because of climatic and physiographic conditions. In order to prepare landslide susceptibility mapping, at first, landslide distribution map and the map of effective factors were supplied by field study. Then prioritization of effective factors was carried out using AHP method and seven factors were selected as most effective factor. Then landslide hazard zoning carried out using information value and AHP models. Results showed that Shemshak formation, fluvial terraces, distance of 500 meters from road, distance of 400 meters from drainage network, the west dip direction, slope of 15-50 percents, elevation of 1500-2100 meters, residential and agriculture-garden landuse have the highest landslide susceptibility.
M. Fatemi Aghda; M. Rahbar; M. Mojezi; G. R. Asadollahfardi
Abstract
Every year, all over the world, landslides cause considerable damage to life and property. In order to prevent the danger and destruction brought about by landslides, it is important to identify the reasons for the occurrence of this phenomenon. This can only be achieved by conducting a thorough investigation ...
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Every year, all over the world, landslides cause considerable damage to life and property. In order to prevent the danger and destruction brought about by landslides, it is important to identify the reasons for the occurrence of this phenomenon. This can only be achieved by conducting a thorough investigation into the geological conditions of the region and a study of the local and global landslides that have occurred in the past across the years. In this research, the reasons for occurrence of landslides in the region have been studied, in addition to the identification of lithological, geological, morphological and tectonical characteristics of the region around the dam. In abutments, landslides occur due to weak lithologies, discontinuities and a high topographic gradient. Landslides around the reservoir occur due to an increase in pore water pressure and changes in water level of the reservoir, in addition to the reasons mentioned above. Finally, the importance and the role of this phenomenon regarding dams and the region have been studied and explained in this research.
S. Hashemi Tabatabaei; A. A. Musivand; S. M. Safavi; B. Akbari
Abstract
Landslide and flood are natural disaster which can create tremendous lose of life and properties. The combine occurrence of these events can create debris flow. Due to the repetition of debris flood in different locations of northern part of the country (Neka, 1378, Kolastan, 1380, and 1384), and tremendous ...
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Landslide and flood are natural disaster which can create tremendous lose of life and properties. The combine occurrence of these events can create debris flow. Due to the repetition of debris flood in different locations of northern part of the country (Neka, 1378, Kolastan, 1380, and 1384), and tremendous destructive power of this natural event, it is essential to assess the effective parameters in development of debris flow. In this paper the condition of masouleh debris flow is reconstructed to assess the effective parameter and suggest possible remedial measures. After a short and intense rainfall a huge flood along with considerable amount of particles ranging from silts to boulder contents striked masouleh town and obstacled the main bridge. This event diverted the debris flood towards the town and caused lose of life and properties. About forty percent of sub basin area is affected by landslides. The rock slides have affected 25.7 percent of the area at the southern part of basin. Various methods were used to estimate the required discharge flow to carry out the material. The optimum method was chosen according to study area condition. The filed investigations clearly demonstrated the river cross sections of upstream can not permit the huge boulders to cross and the big boulder which obstacle the main bridge has been removed from landslide area at downstream at the vicinity of the town.
M. Mahdavifar
Abstract
A new method is developed using modification of Anbalagan method (1992) for slide hazard zonation in coastal desert area. A region in the south of Iran is studied using the method, and the result is compared with the result of zonation using Anbalagan method. This comparison shows that the use of new ...
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A new method is developed using modification of Anbalagan method (1992) for slide hazard zonation in coastal desert area. A region in the south of Iran is studied using the method, and the result is compared with the result of zonation using Anbalagan method. This comparison shows that the use of new method can provide better results for slide hazard zonation in coastal desert area in the middle scales.
P. Garaei; K. Soleimani; S.R. Mousavi; A. Kavian
Abstract
In basins of the northern part of Iran, combination of natural and human factors has intensified landslide and related numerous damages. The investigation importance of this phenomena and effective factors of landslide occurrence and also determining susceptible zones it order to preventing and avoiding ...
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In basins of the northern part of Iran, combination of natural and human factors has intensified landslide and related numerous damages. The investigation importance of this phenomena and effective factors of landslide occurrence and also determining susceptible zones it order to preventing and avoiding its effects is required. At the beginning, of this research after field investigation, review of previous works in similar Lajemrood basin and using questionnaire, were recognized primary effective factors on landslide occurrence. Thin preparing effective factors maps in Geographic Information System. In order to quantifying the factors and weighting them, landslides percentage in different units was determined. For statistical analysis of multiple regressions the stepwise method was used which concluded with ignoring the elevation factor as regional model. Finally, geology, land use, slopes and distance from the road has the most effects on landslides. For evaluation of the accuracy of this model, neighboring basing (Varakee basin) with similar characteristics was chosen. The results have indicated that the most recorded area landslides in Varaki basin occurred in high and high hazard zonation. Thus, it can be concluded that presented model can be used for the study area.
S.H. Tabatabaei; A.S. Salamat; A. Rahnama
Abstract
This paper describes a multidisciplinary approach for evaluation of statically triggered landslide that occurred in Germi, Ardebil province on 1382. With respect to the evidence, no other mass movement was recorded in the adjacent areas despite the geological and geomorphological homogeneity. Field observations ...
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This paper describes a multidisciplinary approach for evaluation of statically triggered landslide that occurred in Germi, Ardebil province on 1382. With respect to the evidence, no other mass movement was recorded in the adjacent areas despite the geological and geomorphological homogeneity. Field observations indicate that subsurface water level changes are the most important parameter in triggering the landslide. Hence, the study was focused on an analysis of the role of subsurface water level changes in triggering the landslide. The slope inclines steeply at crown and very gentle towards the toe of landslide. Field data dealing with geomorphology, geophysics (vertical electrical sounding or VES) and geotechnics were acquired and analyzed with the service of Rock Work 2004 and Arc GIS softwares in order to investigate the cause effect relationships between water level changes and mass movement. The geophysical survey detected two buried paths on the flanks of landslide and a three layer internal structures composed of surface deposit, natural bed rock and saturated zones. Based on the results, 21 test pits were located and excavated to the depth of hard layer. Representative material of the study area was selected and tested. Based on the lab tests, the slope was analyzed using Slide Software and remedial measures were recommended.
J. Ghayoumian; S.M. Fatemi Aghda; O. Ataee; M.H. Davoudi; A.A. Norouzi
Abstract
In this research a Decision Support System (DSS) has been used to support decision makers for policy making regarding the landslides which typically take place around villages. Definite software was utilized to design a model which include three strategies: landslide ...
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In this research a Decision Support System (DSS) has been used to support decision makers for policy making regarding the landslides which typically take place around villages. Definite software was utilized to design a model which include three strategies: landslide stabilization, village relocation, and risk acceptance. The model introduces the optimal strategy considering four effects (i.e., cost, reduction of fatalities, peoples and local manger point of views). To determine the cost of stabilization, in the first step the stabilization method should be selected. This is also is performed using the other DSS system. In the next step, the cost of stabilization is computed. The cost for the other alternatives is also assessed. The other effects are evaluated for the other alternatives. The user can select the optimal method for a certain landslide after completing the designed questionnaires regarding engineering geological characteristics, reduction of fatalities, people and local manger point of views. The Barikan landslide in Taleghan region was studied using the model. The stabilization method was selected as the most appropriate strategy for the landslide. The selected alternative is in a good agreement with those presented as the results of site investigation.
