جستجوی مقالات مرتبط با کلیدواژه « mass movement » در نشریات گروه « جغرافیا »

Nir-Sarab communication Route; Due to special geological, climatic, geomorphological features and human activities, it has been affected by landslides for a long time. Therefore, according to the importance of the subject, the current research aims to evaluate the risk of landslides in this communication route by producing risk zoning maps and comparing two multi-criteria decision-making models, MARCOS and CODAS. For this purpose, first by examining research sources related to the subject, some of the most important factors affecting the occurrence of this phenomenon include; Height, slope, direction, lithology, land use, distance from the fault, distance from the road, distance from the river and precipitation 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 MARCOS and CODAS multi-criteria decision-making methods. The results of the study showed, respectively; The factors of the slope, land use, and lithology have the greatest influence on the occurrence of landslides in the region with weight coefficients of 0.176, 0.152, and 0.124, respectively. According to the output of the CODAS method, respectively; 121.25 and 187.96 square kilometers of the range area, and according to the results of applying the MARCOS method, 85.32 and 201.76 square kilometers of the range area are in high-risk and very high-risk categories. Validation of the used multi-criteria decision-making methods, using the ROC curve method, very good accuracy of the CODAS method, with an area under the curve of 0.76, and excellent accuracy of the MARCOS method, with an area under the curve of 0.87, is an expression.

Among the biggest disasters and natural disasters, landslides have taken the seventh rank in terms of casualties. Considering that, landslides are one of the most destructive natural disasters and cause severe changes in landscape morphology and damage to natural and artificial structures on earth (Tanias and Lombaro, 2019). Identifying landslide-prone areas and producing accurate maps of landslide susceptibility zoning are important issues for risk management studies and are vital to reduce landslide disasters (Kalksen et al., 2016:54; Rabi et al. colleagues, 1:2022).The upstream basin of Yamchi dam, with an area of 698 square kilometers, is located between the Sablan volcanic massif in the north and Bozgosh mountains in the southwest. The highest point of the basin is the peak of the Heram Mountain with a maximum height of 4505 meters above sea level and a minimum height of 1506 meters at the Yamchi Dam site. The climate of the region is semi-arid and very cold. In terms of tectonics, the studied area is located in the tectonic zone of Western Alborz-Azerbaijan. The different lithological units of the region are spread in volcanic and sedimentary forms.

The current research is of an applied type and its research method is an analysis based on the integration of data analysis, geographic information system, and the use of multi-criteria analysis techniques. the ENVI, Ecognition, Arc GIS, Idrisi, and Excel software were used for image processing and data analysis. To assess the risk of landslides, first, the effective factors (including slope, aspect, dem, lithology, soil, land use, rainfall, distance from communication road, distance from the river, and distance from fault), according to natural and human conditions The area was identified. In the next step, information layers related to each of the factors were prepared in the geographic information system environment. The weighting of the investigated factors was done according to the CRITIC method and the final analysis, using CODAS and MARCOS multi-criteria methods. After preparing the landslide sensitivity map, the accuracy of the models has been checked using the ROC curve.

According to the obtained results, respectively; Slope factors with a weight of 0.14, land use with a weight of 0.13, and lithology with a weight of 0.12 assigned the greatest role in the occurrence of landslides in the basin. Examining the high-risk and high-risk points introduced by the reviewed algorithms shows; In terms of the slope criteria, according to the output of the CODAS algorithm, the areas with high and very high-risk probability are located between 10-65% slopes. Examining the output of MARCOS and comparing it with the slope map also shows that the slope values of high-risk and very high-risk points are between 15-50%. According to the criteria of land use, according to the results of both methods, agricultural use, pastures, and man-made areas have the highest level of areas with a very high probability of danger. About the lithology map, it can be said that according to the zoning map resulting from the application of CODAS and MARCOS methods, very high-risk and high-risk classes, mainly; They are seen in formations with very low and medium resistance and limited form, in areas with resistant lithology.The results of the overlap of the output from the examined models, with the distribution of sliding points; showed that according to the CODAS multi-criteria decision-making algorithm, 22.58 and 54.84 percent of the slip points are in the high-risk and high-risk category, respectively, and according to the results of the MARCOS method, 51.62 and 29.03 % of the slip points are in the very dangerous category.

According to the output of the CODAS method, respectively; 139.46 and 58.17 square kilometers of the area of the basin and according to the results of applying the MARCOS method, 114.01 and 54.07 square kilometers of the area are in the high-risk and very high-risk categories. The investigations carried out in this analysis show that in the upstream basin of Yamchi Dam, due to its mountainous nature, cultivation in sloping lands, excessive grazing of livestock in pastures, presence of deep soils on Steep slopes, and water infiltration into the lower layers of the soil have created a suitable ground for the formation of the landslide phenomenon and will cause a lot of damage. The results of the ROC curve, showed that the accuracy of the method CODAS, with an area under the curve of 0.72, is very good, and the accuracy of the MARCOS method, with an area under the curve of 0.81, is excellent.

Introduction:

The environmental factors in different regions play the key role for the development of settlements. The rural settlement is affected by these factors too. On the other hand, human beings from the beginning of life up to now have been encountered with a variety of injuries and natural hazards and they have suffered various life and financial injuries [1]. The word natural hazards represent the occasion that our economic development is unacceptably fragile, and is too vulnerable to nature's behavior [2]. The aim of the research is to study the role of environmental factors for the settlement of villages focusing on natural hazards. The research scope is the natural boundary of Siyahrud watershed which is located in Gilan province, Rudbar city. Hence, such a question is raised in this research if natural hazards are considered to the distribution of rural settlements in the basin; which categories of hazards can play the role the most to the destruction of settlements? 

Material and Methods:

There have been seven environmental parameters considered in Rural Settlement which are: Altitude, Slope, Aspect, Fault, Soil, Land Use, Rivers and Roads. The effects of each parameter on the settlements investigated, too. Natural hazards were divided into two groups: Earthquake and Mass Movement. The hazard warning distance is considered 1000 meters from the epicenter of the Earthquake.The Inverse Distance Weight (IDW) method was used to interpolate the magnitude of the earthquake based on 281 points inside the basin. Aspect, Slope, Fault, Road, River and Geology have been the most effective perimeters in Mass Movement. So, they were overlaid with the 34 occurred- Landslide Points. Consequently, the final output of Landslide Zoning was obtained.

Conclusion:

The result of studies shows that Land Use, Altitude, Slope and Water in the past have played a key role to village settlement while other environmental factors such as Faults, Mass Movements and Geology have not been considered at all. Moreover, Road and Land Use have been considered after the construction of settlements. There are around 15000 people living in distance of 1000 meters from the fault and around 10000 people, 1000 meters from existing Mass Movements in the basin. So, this can be an alarm for the officials of Rudbar city, to renovate rural housing here.

IntroductionA landslide is a natural phenomenon that often occurs because of falling down or seamless and quick movements of volumes of sediment along the slope. It has such speed and extent that it may influence tens or hundreds of cubic meters of rock and soil together. This phenomenon causes a lot of economic damages to forests and their growth, farmlands, gas and power transmission lines, mines, engineering structures, and buildings. One of the best ways to prevent these damages is preparing a landslide hazard map.
MethodologyThe method used for zoning the Sardool Chay Basin is the Analytical Hierarchy Process. This is one of the most comprehensive multi-criteria decision methods, which was first presented in 1980 by Thomas L. Saati. This method is based on weighing each pair of variables with each other. AHP method consists of three main steps including (1) creating an Analytical Hierarchy, (2) comparing pairs of elements in it, and (3) weighing the criteria. The main feature of this method is the use of expert opinions. In AHP,n paired factors are compared with each other and more weight is given to the layer that has the maximum impact on the target set. The paired comparison of a scale, based on1 to 9, for its two component's relative weighing is hierarchical.
DiscussionIn this study, the landslide hazard zonation was used in the Sardool Chaycatchment in order to identify areas with landslide incidence potential. The main factors contributing to the landslide occurrence in this case study consisted of geology, land use, slope, aspect, rainfall, altitude, distance from faults, and distance from stream. Their layers were prepared in ArcGIS software. An Analytical Hierarchy Process in Expert Choice software was used for paired comparisons of criteria and calculation of final weight. The results indicated that the geology criterion, which weighed 0.343, and the slope criterion, which weighed 0.215, had the most influences on landslide occurrence.
ConclusionLandslide is one of the most common environmental hazards in mountainous areas of the northwest of Iran. Factors such as slope, rainfall, lithology, and earthquakes can trigger them. One of the best ways to deal with this phenomenon, before the implementation of any project, is the zonation mapping of the area. This study was based on the Sardool Chay catchment, located in Khalkhal, the southern part of Ardabil Province.
To this end, 8 factors including geology, land use, slope, aspect, rainfall, altitude, distance from faults, and distance from stream were used. The weighting factors and the Analytical Hierarchy Process (AHP), and the Expert Choice software were used. The results classified the basin into five areas including very high risk of landslides (65 km²), high risk (144 km²), medium risk (202 km²), low risk (142 km²), and very low risk (120 km²). In addition, it indicated that the landslide risk of the Sardool Chay catchment is medium. Comparing the landslide zonation map and points of distribution suggests that the AHP can be a good method of weighing the criteria involved in the happening of the landslide.

One of the causes of mass movement is the presence of faults. The studied basin in this research was Khezr-Abad Basin, one of the sub-basins of Yazd-Ardakan plain on the northern slope of Shirkouh mountain range in Yazd which is located between 53 - 41'-30" up to 54 - 12' of east longitude and 31- 46'-00 up to 32-06'-00 of north latitude. and there are over 418 km of faults in the basin. This basin is part of the city of Sadukh and located in the south part of the city. In this study, the fault weight were identified through the geomorphic indicators and In order to prove the region's activation, the mountain front sinuosity index and rock formations photo lineament recognition through areal photos, satellite photos (remote sensing) and Geology Maps has been performed that the index action in the East Zone was 1.2 and in the western zone was 1.3, which indicates that the basin is morph tectonically active. Then by identifying the fault zone in the region and identifying the main and minor faults and preparing faults maps in the Arc GIS, the effect of the fault zone on the formation of mass movements was evaluated.

This study was designed to investigate the role of tectonics and lithology of the major parameters affecting slope instability in the study area is examined. The study revealed that about 90% of the body surface elevations north basin sedimentary formations are composed of water spreading Tasuj. Performance of heavy tectonic especially to resistant and non-resistant, creating congestion fault-up (km2 / km) 2/2 with rule systems, Periglacial erosion, especially at altitude 1700 meters high makes up the physical degradation of rocks and receding cliff streams Banks typically isolated, drawn very widely in the region to form. To study aims to investigate the software Arc GIS and remote sensing data used and eventually plans to map geological tectonics and lithology and sensitivity of mass movements in the unstable range, the combination of combine the. The results show that the instability prevailing in the region, mainly debris slope range (Debris slide) and debris valley (Debris flow) and their dynamics have also mostly of natural origin, which are among the factors to be effective the role of tectonics and lithology, geological structure associated with susceptibility to type such important parameters affecting their pay. The results of quantitative analysis showed that the most unstable range (mass movement) due to faults in the region and formations susceptible to erosion has occurred.

Mass movement is one of the natural hazards with regard to frequency of which and its strength there are two consequences direct (blocking the rads and the direction of waterways، burring the residential areas and service installations) and indirect consequences (environmental unpleasant effects، making the soil useless، increasing the sedimentaion and decreasing the capacity of dams). The present research was carried out on Kalan dam watershed in Malayer to distinguish the effective factors in the mass movement and recognize prepared areas for mass movement and appointing the weight which states the standard role of these factors in mass movement occurrence. Factors such as lithology، space of faullts، slope، altitudinal surfaces and rainfall are chosen as the most effective factors in the mass movement occurrence. By using geological maps، topography and aerial photos in the from of geographical information system (GIS) and ArcGIS software، we used LNRF model in the maps in the numerical and stratum from for analyzing the obtained data through studying the effective variances as the research conceptive tools. We finally prepared the zoning map of the mass movement danger by combining various strata (layers) through weighting to the effective factors and their algebraic conclusion and the results show that the LNRF model is a good competence to study the data and zoning of mass movement in Kalan dam basin.

Identification of effective factor on mass movement events and risk zoning is one of the basic tools for mass movement control and appropriate and effective option. Thus, the aim of this study is recognizing effective factors on mass movement and determination hypothetical lands, then pay to mass movement mapping in West Azarbaijan province.
For this reason first of all, important effective factor on mass movement event were determinate. In this study, most mass movement data were obtained base on direct observation. In field study, phenomena location, its approximate measuring, hillside material sampling and region determination was perform.
Then, using over laying, accruing different instability zones, field observations and expert opinions deal with to zoning different mass movement in West Azarbaijan province. For this reason Arc­ GIS and Arc View were used. One of another option in this study is adjusting the phenomena with satellite and aerial picture.
The results show that the solifluction and Creeping with about 757898.8 hectare covers almost 20 percent of western Azarbaijan province. Also among the different towns in the province the most probable mass movement is related to Khoy. This mass movement over than 556092.29 hectare approximately includes 14.7 percent of the total mass movements of the western Azarbaijan province.

Identification of regions having potential for landslides occurrence, is one of thebasic measures in natural resources management. In this Study, in order to preparinglandslides hazard zonation map in Safaroud watershed, by using geographicinformation system software (ArcGIS9.3), topographic maps (1:25000), fieldobservations and interpretation of aerial photo, basic maps such as geographical map,hypsometry, slope Degree, slope aspect, the average annual rainfall, maximum 24-hour rainfall with return period 100 years, the maximum earthquake acceleration andthe distance of roads, rivers and faults, is produced. Then using Logistic RegressionMethod, landslides hazard zonation map of this watershed is prepared. The resultsshowed that 52.28 percent area of Safaroud watershed have had high and very highclasses of hazard, and theses areas are located on formations content layer of silt stone,sheyl, sandstone, conglomera and coal, on Slope from 15 to 35 degrees, close to roads,rivers and faults and in the average heights (1000 to 1500 meters asl.) that have largeamount of rainfall (more than 850 mm).