Journal of Spatial Analysis

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Today, urban and regional issues related to sustainable development is a key challenge for policy-makers, planners and specialists in various disciplines. Geomorphologic studies can be useful and effective in analyzing and deriving acceptable means to assess the growth and development of the city, and to set criteria to determine the directions of urban development.    Landslides range of motions not only affect the human structures such as roads, rail lines and residential areas, but also lead to casualties. Tehran metropolis mountainous basins, including Kan, Vesk, Farahzad, Darake, Velenjak, Darband, Golabdare, Darabad, Sorkheh-Hesar, and Sohanak due to the lithology, geologic structure, weathered sediments, steep slope, rainfall and poor urban development are considered as one of the places where landslides are a range of geomorphologic processes can be studied.    At this research, using Fuzzy and AHP methods and by the use 8 factor variables such as lithology, elevation, slope, aspect, annual rainfall, maximum daily rainfall, distance from fault and drainage system. the map of landslide zonation hazard in mountainous areas of the city is prepared to determine risky strips. After the standardization of the criteria for the occurrence of landslides and using frequency ratio method and fuzzy model and functions, Landslide hazard zonation maps was prepared for evaluating from the fuzzy sum, fuzzy product and fuzzy gamma operator 0.8 and 0.9. Then the final map of landslide zonation, obtained from the above-mentioned method matched with the map of urban regions in mountainous areas. In this way the constructed region have been distinguished from very high and very low hazard zonation.    Lithological studies showed that most of the basin areas covered by Karaj Formation. About 45/7 percent of units with sliding movement in areas with "rock crystal tuff and tuff lytic green, with the layers of limestone" (unit Et2) of the intermediate tuff formation occurred. Cross of faults distance map with landslide density map showed that about 33/1 percent of landslides occurred within 200 m of the fault lines and 78/4 percent of landslides occurred within 500 m of drainage network. Most sliding movements (60/2 percent) in the range of 1900 to 2500 meters altitude and about 35/3 percent of this type of range of motion in height of 1500 to 1900 meters occurred. This area is about 81/6 percent of sliding movements in slopes between 15 and 40 degrees (26/8 to 83/9 percent) and about 17/6 percent on slopes less than 15 degrees (26.8 percent) occurred. In the aspect, sliding movements of the basin, mainly in the south-western slopes (about 23/2 percent), the South (about 17/5 percent), West (about 16/6 percent) and Southeast (about 77/1 percent), northwest (about 33/1 percent) occurred. About 88/9 percent of sliding movements in areas with average annual rainfall of 244 to 280 mm occurred. According to the zoning map, 12 percent of mountainous basins area (approximately 10,057 acres) is in the zone of very high risk, 33 percent (approximately 27,723 acres) is in high risk areas, 20.5 percent (approximately 17,143 acres) in the moderate risk zone, 30/ 7 percent (approximately 25,672 acres) in area and 3.8 percent of the total area of the basin, low risk (approximately 3172 acres) located in low risk areas. The results showed that approximately 5.2 hectares (about 0/05 percent) of the urban in zones with a huge landslide, about 51/5 acre (approximately 1 percent) in zones with high landslide risk and about 821 acres (equivalent to 25/16 percent) in the medium risk landslide zones are located and developed.     The final results indicate that some mountainous regions of Tehran Metropolis are apt to landslide with middle to high risk. (Apart from strengthening the vulnerable area) avoiding these areas is an important solution to decrease damages caused by landslide.

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One of the geomorphologic issues that many human activities affect is the landslides. Natural factors and human activities on the other hand, these events are triggered. Landslide one of the most active hazards are natural processes that lead to erosion and changes in the landscape. Iran is a predominantly mountainous topography, seismic activity and high landslide, diverse climatic and geological conditions of natural conditions for a wide range of slip is important. Located in second place in the sector of industry, population of 1695094 people, proximity to major faults of Tabriz and occurrence Landslides of different city of Tabriz, the city has become one of the most dangerous cities in the environmental hazards, especially landslide. In these circumstances and completed a comprehensive review and a detailed zoning of land for landslide susceptibility seems absolutely necessary. The purpose of the present paper, the occurrence of landslide susceptibility assessment and mapping potential occurrence of landslides in the city of Tabriz in this range.

     This research of the type applied- development research and of the research method is descriptive - analytic. In this study, using a variety of sources including satellite imagery, aerial photography, global positioning system (GPS) and field studies landslide occurred in the study area were identified and these data were analyzed using the software ILWIS and use of library studies and expert opinions should identify the criteria and sub-criteria and range were classified. Then, using fuzzy TOPSIS model, the importance of the criteria and sub-criteria specified in pixel units and finally combining fuzzy-TOPSIS model and overlapping functions in ARC / GIS final map was extracted.

Geomorphologic and lithology conditions of the city with its mountainous location where the trigger landslides. The final results indicate that over 30% of the areas of the city of Tabriz are medium to high risk that this areas of land in the north and northeast is sparse. The accuracy of the final map and the map of the distribution of faults and the accuracy of the study proved to be that hazardous zones roughly corresponding to the final map lapses occurred. So we can conclude that the method and the model presented in this paper is an effective method for landslide hazard zonation within the cities.

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Landslides are considered as natural disasters that lead to many deaths and severe property damages worldwide. Therefore, it is necessary to investigate the effective factors in order to make urgent planning and to present management solutions for the sensitive regions. Massive movement of materials, such as a landslide, is one of the problematic hillslope processes in Javanrood located in the northwest of folded Zagros, for this phenomenon leads to demolition of forest lands, farms, and pastures of the region. Moreover, it is considered as a threat for road traffic. The present study aims slope stability analyses and landslide hazard zonation applying the process-based model (Sinmap).
This research was done by both field and experimental methods. Research steps are summarized as following.
Geomorphologic, hydrologic and soil mechanic characteristics of slopes in the considered zone were the required information in this study. To obtain this information, at first, it was necessary to recognize sample slopes to measure the above- mentioned variables. Therefore, first of all, landslides distribution map was prepared in the considered area then, on this basin, sample slopes were selected to measure essential variables. Sample hillslopes were recognized as 12 hillslopes, 5 stable (lack of land sliding) and 7 unstable hillslopes (having land sliding mass). They were 1- 12 numbers. 1-5 hillslopes are stable and 6-12 unstable. After selecting sample hillslopes, necessary parameters were assessed as following:
Mechanical features of soil: soil sampling from each hillslope was done the mechanical features of soil, so 50 kg soil was removed from each slope, from 75 cm to 1cm depth. In order to sampling soft and coarse soils, a core cuter devise and shovel were used, respectively. Sampled soils were transferred to Kermanshah soil mechanic laboratory, Kermanshah provincial transport office and necessary parameters, including dry soil specific weight(γ d), wet soil specific weight (γt), hydraulic conductivity , soil internal friction angle(φ) ,soil cohesion , and soil porosity were determined by using direct shear test.
Determining the geometric parameters of slopes: except for using topography map, altitude numerical model (Dem) with a pixel size of 20 by 20 m and satellite images were used to determine morphology parameters and to identify various hillslope types. Applying GIS software, manual and laser tape measure, clinometer, slope geometry characteristics such as mean slope (beta), slope width (W), slope length (L) area, were extracted.
Model implementation
The model used in this study was Talebi (2008) model which was, in fact, an extended model of process-oriented (physically based) model, being a combination of geometry model, hydrology model (permanent condition) and infinite slope stability theory. After obtaining necessary parameters to get slope factor of security (F S) including laboratory, topography and hydrology parameters, Fs values for each slope were measured by Matlab software
Unstable slopes of the region mainly have the stability coefficient less than 1 which is classified as very high vulnerable class. They have low inner friction angle, less than 29 degrees, based on geo-mechanic properties of soil. Moreover, their gradient angle is more than 35 percent. In term of shape, most of them have concave profile curvature and convergent plan which lead to slower drainage, the increase of relative saturation saving of the soil, and the decrease of stability. The results of the landslide hazard zonation mapping indicate that the majority of the study area located in protection class includes 26 percent of the study area. The lowest percentage of study area belonging to middle stability and quasi-stable classes which constitute 9.2 and 6.2 precent of the study area respectively.

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 Quantitative assessment of landslide sedimentation in the ILAM dam Basin

Information on the accurate volume of landslides and sedimentation in landslides is a research necessity, with the assumption that the bulk of sediment accumulated in the ILAM Dam (located between , E and , N) is related to the surface landslides of the basin. Although the role of landslides in erosion, sediment transport and sedimentation of slippery basins is confirmed and different experts understand and determine the relationship between the fluctuation of slopes and the fluctuation system in many respects more important than other areas. Because according to the results they can assess the widespread environmental changes, but comprehensive research on the scale of catchment basins has done very little (Harvey 2002). So far, the study of wet landscapes in Iran has been more sensitive to the factors, their sensitivity and their hazards, and there has been no study on the sedimentation of landslides.

Data and Method
First, using a geomorphologic system methodology with topographic maps of 1: 50000, geological map of 1: 100000, aerial photography1: 20000, Landsat TM1988 ETM2002,2013 satellite imagery, and Google Earth in the GIS environment in the following sub-basins and landslide events at the following levels The basin was drawn. The discharge data of the water and sediment flow of three hydrometric stations GOLGOL,CHAVIZ and MALEKSHAHI Station were provided from the waters of the ILAM province. Two models of estimated MPSIAC and EPM models have been used to estimate soil erosion and subsoil sedimentation. The Moran spatial correlation model was used to introduce the spatial pattern of landslides, and the fuzzy logic model was used to determine the relationship between the dependent landslide to the independent variables and the potential risk of landslide hazard in the basin. In order to elucidate the quantitative results of landslide sedimentation, empirical models of estimation of sediment erosion, hydrological model of discharge curve and sediment, observational statistics of sediment during statistical period, landfall time occurrence in compliance with the hydrometric station sediment peak during the statistical period of computation Estimated a small amount of sedimentation of the landslides of the ILAM dam basin.
Result and Discussion
The spatial correlation model of Moran showed that the data have spatial correlation and cluster pattern. The average total sediment production in the MPSIAC model in the GOLGOL basin was estimated to be 13.3 tons per hectare per year under the CHAVIZ basin of 10.3 tons per hectare for one year and 4.00 tons per hectare in the sub-basin MALEKSHAHI. Using hydrological model of discharge-sediment curve, the mean sediment was calculated during the statistical period at the hydrometric station of the sub-basin of GOLGOL 18.8 ton per hectare, the station CHAVIZ 10.4 tons and the station MALEKSHAHI 0.9 tons of sediment per hectare per year was calculated. According to the results of the research methodology, the observation of the sediment in the two stations of GOLGOL and CHAVIZ compared to estimated sediment is related to the events occurring in these two sub-basins.
The data of 16 active landslides were recorded. Under the GOLGOL basin, 9 landslide events occurred, and in the CHAVIZ basin, 7 landslide events, the time of landfall occurrence recorded with sedimentary peaks, the length of the statistical period, the precipitate in the sub-basins was almost synchronized. Average relationship between suspended period of the statistical period - average of the peak delayed flight time of the statistical period coinciding with the occurrence of landslide = the amount of suspended load of landfall occurrence in the basin.
The amount of suspended land slip under the GOLGOL 75088.19 - 315.85=74772.34
Landing slope under the Chavez Basin 19907.30 - 20.24=19887
The area of the sub-basin is about 29,000 hectares and the active landslide area is about 100 hectares. According to the calculations, 77772.34 tons of suspended sediment is a sedimentary passage passing at the GOLGOL hydrometric station, which shows with a coefficient of 1.4 times the suspended sediment load of approximately 104681 tons of landslide sedimentation in this sub-basin, which shows the amount of sediment yield 100 hectares of landslide, so each landslide hectare had an average of 1046. 81 tons of sediment deposited at the GOLGOL hydrometric station. The area under the Chavez Basin is about 14000 hectares and the active landslide area of this sub-basin is about 65 hectares. According to the data of the discharge data, the sedimentation of the Chavez hydrometric station is 19887 tons of suspended sediment load, which shows a 1.4 equivalent of 27842 tons of landslide sedimentation in this sub-basin, equivalent to a slope of 428.33 tons per hectare.
Conclusion
According to the calculations, it is concluded that in the sub-basin of flowering GOLGOL, 37.35% is equivalent to 4.9 tons per hectare per year, the increase of sediment is related to landslide events. As a result, 28.2 tons of sediment per hectare were introduced in one year Dam reaches ILAM. The results showed that in the CHAVIZ sub basin, 38.2 percent is equivalent to 4.6 tons per hectare per year for the increase of sediment related to landslide events. As a result, an amount of 14.5 tons of sediment per hectare has entered ILAM dam in one year. In the sub-basin MALEKSHAHI, there was no increase in sediment during the period without active landslide occurrence. A total of 1237314 tons of landslide deposition have entered the ILAM Dam. To control this threat, the appropriate action by the executive office for sustainable development should be applied.

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Landslide susceptibility mapping is  essential for  land use  planning and decision-making especially in  the mountainous areas. The main objective of this  study is to produce landslide susceptibility maps (LSM) at Dalahoo basin, Iran  using two statistical models such as an  index of entropy and Logistic Regression and to compare the  obtained results. At the  first stage, landslide locations identified by Natural Resources Department of Kermanshah Province is used to prepare of LSM map. Of the 29 lanslides identified, 21 (≈ 70%) locations were used for the landslide susceptibility maps, while the remaining 8 (≈ 30%) cases were used for the model validation. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, distance to faults, distance to rivers, distance to roads, land use, and  lithology  were extracted from the spatial database. Using these factors,  landslide susceptibility and weights of each factor were analyzed by index of entropy and Logistic Regression models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and  the areas under the curve (AUC) were calculated. The verification results showed that the index of entropy model (AUC = 86.08%) performed slightly better than conditional probability (AUC = 80. 13%) model. The produced susceptibility maps can be useful for general land use  planning in the Dalahoo basin, Iran.

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Active tectonics of the Roudbar region:
with special reference to the landslides of the area
 
Tayebeh Kiani, Assistant Prof. in geomorphology, Kharazmi University
tayebeh.kiani@gmail.com
 
Hyrdad Nadim, MSc in environmental geology, geological hazards trends, Geological Survey & Mineral Exporation of Iran
hirad.nadim@gmail.com
 
Parastoo Ghaforpur Anbaran, PH.D Student in Geomorphology, Kharazmi University
parastooghaforpur@yahoo.com
 
 
 
Extended abstract:
Introduction: Due to its specific morphology and extensive tectonic activities, Roudbar rigion has always been affected by various geological hazards such as earthquakes, floods, biological pollution and landslides, which landslide is one of the most active phenomena in the region of this vast And mountainous area. Within the Roudbar geological sheet, 11 large and small landslides have been recorded with different yields and properties, some of which have catastrophic consequences, including the Roudbar and Fatalak landslides, which occurred as a result of the earthquake of June 31, 1990 Has caused devastating events in the Roudbar area and resulted in casualties and financial losses. Extreme performance of tectonic phases, which enact a major role in landslides, construction factors, road and rail, Steep slopes of topography, Sloping Loose Materials, are a various factors in the occurrence of such landslides. Due to the fact that landslide is predictive, preventive and sustainable, it is important to identify and zoning in the country and province and Perform basic geological studies in prone araes to landslides with a large scale. Due to the high potential of the region for the subsequent landslides and the properties of the intact areas with the old landslide areas, In present research, it is necessary to determine the most important factor in landslide occurrence in Roudbar area through field investigations and based on that, plan management will happen for controlling landslide phenomenon. Eventually, using geomorphic indices, the tectonic activity status of the Roudbar region is determined, and with the adaptation of the location of landslides and faults with the tectonic activity zones map, relationship between tectonic and landslide are investigated. Also, the risk zone, where there is a probability of landslide instability, is determined.
Method: The study area is located at 45 ° 36 'to 30 '45 ° 36' north latitude and 30 '22 ° 49' to 49 ° 49 'east longitude. Roudbar is one of the southern cities of Gilan province, which has a reputation for having olive gardens, and is named after its seasonal and permanent rivers. Roudbar city leads to from north to Rasht, south to Roudbar Alamut (from Qazvin province), from east to Lahijan and from west to Fomen city.
 In the first phase, based on ground surveys and laboratory studies, the geological map in the scale of 1: 25,000 and other required data, limited area and Condition landslides are identified on aerial photos and satellite imagery. In the second phase of this research, geomorphic indicators the mountain front sinuosity index (Smf), the ratio of width to depth valley floor (Vf), Stream Length Index (SL), Basin Shape (Bs), Asymmetry Factor (AF) are used. Then, the results of the indicators are presented as a tectonic activity index (LAT).
Conclusion: Based on ground surveys and laboratory studies, the geological map in the scale of 1: 25000 and other required data, limited area and Condition landslides are identified on aerial photographs and satellite imagery. Based on this, it was found that Roudbar landslides were more affected by structural factors and weight (slope loading) has taken place. It seems Structural factors hidden in most of the landslides in the region. Based on the results of the tectonic activity relative index (Lat), most sub-basins have high and moderate tectonic activity. In term of width, the intense class includes with 195.55 square kilometers (67.21%) of the total area. The integration of different tectonic zones with the location of the landslide zones of the region, the close relationship between the zones with intense and moderate tectonic activity with the landslide zones designated in the first part of this study shows that the zones with Fatalak, Lavie, Roudbar, Filde landslides are in areas with intense tectonic activity and The landslides of Dashtgan, Talabar, Taklim, Nesfi, Dolatabad, Herzavil are located in the moderate tectonic activity zone. Based on ground surveys, the results of calculations of geomorphic indices indicate the relation between the activity of the land area and the landslide hazard. Considering the inevitability of the faults' activity and the resulting hazards, it is suggested that, in order to improve the country's substructure development, more detailed and larger scales on the landslide mechanism introduced in this research (Including determination of gradient safety factors (FS), calculation of the risk of slipping region and applying slope stability and safety methods, etc.), be done Systematicly and in coordination with organizations and related departments.
Keywords: Active tectonic, Geographic Information System, Geomorphic indices, Landslide, Roudbar.
 

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Zoning the possibility of landslides downstream of Sanandaj Dam
1-Introduction
The purpose of this study is to select the best model and identify landslide risk areas in the downstream basins of Sanandaj Dam. Every year, mass movements in the region cause damage to roads, power lines, natural resources, farms and residential areas, and increase soil erosion. Kurdistan province, with its mostly mountainous topography, high tectonic activity, diverse geological and climatic conditions, has the most natural conditions for mass movements. According to the available statistics, this province is the third province in terms of landslides after Mazandaran and Golestan. (Naeri, &Karami, 2018). The Gheshlagh River Basin is a mountainous region with a north-south trend. In terms of construction land, it is located on the structural zone of Sanandaj-Sirjan. The study area with an area of 970.7 square kilometers is located downstream of Sanandaj Dam. The city of Sanandaj is being studied within the region. Due to the type of climate and morphological processes, effective parameters are provided for landslides in the geography of the region.
2-Methodology
In this study, 9 effective factors for landslides, including slope, slope direction, fault distance, road distance, waterway distance, lithology, land use and precipitation were used. Using Google Landsat 8 ETM satellite imagery, Google Earth software identified 237 slip points. Then, the coordinates of the slip points were transferred to the Arc GIS software and a map of the landslide distribution area in this environment was prepared. Also, in this study, 89 non-slip points were prepared for use in the training and testing stages of Persephone neural network inside slopes less than 5 degrees. Artificial neural networks are made up of a large number of interconnected processing elements called neurons that act to solve a coordinated problem and transmit information through synapses. Neural networks begin to learn using the pattern of data entered into them. Learning models, which is actually determining their internal parameters, is based on the law of error correction. In this method, by correcting the error regularly, the best weights that create the most correct output for the network are identified. The neurons are in the form of an input layer, an output layer, and an intermediate layer. ahp includes a weighting matrix based on pairwise comparisons between factors and determines the level of participation of each factor in the occurrence of landslides. In this model, a large number of factors can be involved and the weight of each factor can be obtained using expert opinion.
3-Results
According to the results of the high-risk class neural network model, which occupies 31% of the basin area, it is the widest risk zone in the region. The middle class also accounts for more than 29 percent of the area, followed by the low-risk class. The results of the AHP model show that the middle class, with 32% of the area, has the highest dispersion in the region, the low-risk class and then the high-class are in the next position. The AHP model was used to prioritize the parameters affecting the landslide. The parameters of slope, lithology and land use play the most important role in the occurrence of landslides, respectively, and have the least role for slope direction, distance from fault and height. The results of the models used are consistent with the reality of the region's wide-risk hazards, and high-risk areas based on the models used are mostly located in the west and southwest of the basin. These areas correspond to the mountain unit and the steep slope. Based on the results of AHP model, the impact of human factors in the occurrence of landslides is weaker than the natural factors of the region and human factors play a stimulating and aggravating role in primary factors. Five methods for error detection were used to evaluate the models used
4-Discussion and conclusion
 .Due to the sensitivity of unstable slopes in the region, any planning to change the use and construction that increases the weight of the load on unstable slopes should be done in terms of geomorphological and geological conditions of the region.
Keywords: hazard zoning, landslide, neural network, AHP. Sanandaj Gheshlagh Watershed
 

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Risk assessment of Maroun gas and oil pipelines due to land sliding hazard

based on D-InSAR technique

Mohammad Sharifikia, @ Associate professor, Tarbiat Modares University, Department of Remote Sensing-

Iran

Meral Poorhamzah, postgraduate in Remote Sensing, Tarbiat Modares University

Abstract
It is importance to note that Iranian oil company have to transfer this valuable enrage from one side to other side of
country passing form several ridge and valley prone with several natural hazard. This is because the natural sources
of oil and gas generally lied in south west part of Iran locally calling Manathegh Nafte Khize Jonoub (south oil field
area). This area is closed to one of most active geological zone of Iran (Zakrose) covering thousands of kilometer
from south east to north west. Supplying natural enrages to central port of country need to crossing from this zone
which is suffering with several difficulties as well as neutral hazard. Out of neutral hazards can found to excite in
this area, the landslide hazard is a main restriction for pipeline crossing over.
The present research is dale with radar interferometry techniques applying for risk assessment and mapping over the
oil and gas pipelines suffering to landslides hazard in the part of Central Zagros (Maroun-Esfahan). For this purpose,
two individual radar dataset in C (ASAR) and L (PALSAR) band with deferent time were collected. Furthermore,
the D-InSAR technique was applied for land surface movement and land displacement detection. The outcome map
was showed the maximum rate of land displacement in this region is about 7.4 cm uplifted and 3.9 cm subsidence
with duration of almost one year. this is due to shape of landslide over the area’s slop. Overlying the landslide map
with the pipeline crossing route shown at lies three active landslides over the Maroun-Esfahan gas and oil pipelines.
For investigation about this three landslide and damage estimation over the pipeline the field study has been done
for accuracy assessment and land movement rat measuring and evaluation. Which, successfully identified and
mapped 3 landslides were located across the pipeline and damage it. Furthermore, map surveying by DGPS in RTK
method over the one of landslide shown that sliding transfer 20 m with falling 10 m over the length of 45 m of gas
pipeline. moreover, the press of landslide made curvatures on straight pip hogging pipe 43 cm. continued this
landslide activation and more pressing in close further can make a fracture and pessimistic pipe expulsion. With can
a kind of disaster if the event be close to settlements are.
The outcome landslide map shown the active landslide points (small area) very well, but the main think need to
suffusion information about interred area. For this exigency have to convert points data map to area as prediction
hazard. For this proses and to understanding the amplitude of landslide hazard in area the information value model
was applied for hazard zonation and mapping. The landslide hazard map resulting from D-InSAR technique as
inventory map along with 8 data set maps namely, lito-logy, soil, land cover, lineaments, faults, roads, derange
pattern and slop, has been interred to model for zonation and hazard estimation over the area. Furthermore, this map
was reclass in 5 individual hazard and risk class from low to high risk. The hazard map analyses and calculation was
show about 20 percent of area study was marked as high and very high risk zone. This is mainly because of
morphological and lito-logical exclusivity of area resulting by active tectonics. Crooning and overlaying the
landslide hazard map with pipeline track has been shown 28.5 percent of line length crossing over the high and very
high risk zone, where the 52 percent was prone with low and very low risk zone. This mine that near 1/3 of mention
pipeline length suffering from hazardous area which can classified as high risk part of pipeline.
Interpreting the hazardous classes on the prediction map is an important concern in landslide prediction models. For
this purpose, the prediction-rate curve was generated using validation group of landslide locations to validate the
prediction map obtained. This rate curve explains how well the model and factors predict the landslide. Results from
the success-rate curve are very promising, since the 3% area predicted as the most hazardous, includes 42.35% of
the total area affected by landslides, and this value grows to 90%, when about 25% area of highest susceptibility is
considered. The prediction accuracy can be assessed qualitatively by calculation the area under cover. The total area

equal to one means perfect prediction accuracy. In this model ratio area was 0.633 that means the prediction
accuracy was 63.3%.
Keywords: Differential SAR Interferometry, PALSAR, ASAR, Landslide, Oil and Gas Pipeline risk

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Landslide risk assessment is essential for all landslide damage mitigation plans. The purpose of this research is to assess the risk of landslides in the Shahrood watershed of Qazvin province. First, the landslide susceptibility map was prepared using fuzzy operators. the landslide distribution map and also 11 effective factor layers including slope, slope direction, altitude, land use, lithology, distance to road, distance to stream, distance to fault, earthquake acceleration, precipitation, and maximum daily precipitation were first prepared. After determining the frequency ratio and fuzzy membership values for the map classes of different factors, the landslide susceptibility map was prepared using different gamma values. Then, after preparing the fuzzy map of vulnerability for different land use units, the amount of landslide risk was determined from the product of two maps of landslide susceptibility and vulnerability. In general, 104 landslides with a total area of 1401 hectares were recorded in this region, 70% of which were used for modeling (73 landslides with an area of 982 hectares) and the remaining 30% (31 landslides with an area of 418 hectares) were used to assess the accuracy. The evaluation results showed that the highest value of Qs index (equal to 1.34) belongs to the gamma equal to 0.93 and therefore this model has higher accuracy than other gamma values. The importance of features at risk ranges from 0.05 (no coverage) to 1 (residential and industrial areas). To deal with landslide damages, three general policies including suitable for development, prevention, and treatment were proposed, which should be applied based on the two factors of risk and vulnerability for different areas of landslide risk. Finally, in order to reduce landslide damages, suitable land uses for high-risk regions were introduced. 

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Extended abstract
Landslide risk zoning is one of the basic measures to deal with and reduce the effects of landslides. Vernesara watershed is one of the areas where many landslides have been observed in different parts of it. In this research, in order to zone the risk of landslides using the entropy index, first the ranges of landslides were determined, then the effective factors in the occurrence of range movements were prepared in the ArcGIS software environment, and a landslide susceptibility map of the studied area was prepared. . The prioritization of effective factors using Shannon's entropy index showed that the slope layers, land use, surface curvature, topographic humidity index and topographic position index had the greatest effect on the occurrence of landslides in the region. Also, zoning landslide sensitivity with the mentioned model and evaluating its accuracy using the ROC curve shows the very good accuracy of the model (79.6 percent) with a standard deviation of 0.0228 for the studied area. The zoning map shows that the low-risk areas cover only 13% of the area and more than 56% of the area is in the area with high risk of landslides, which indicates the high potential of the area in the occurrence of landslides. . Construction at a distance from fault lines, waterways and the steep Asmari Formation and safety of communication routes are the most important measures to reduce the amount of damage caused by landslides in Vernesara watershed.
Key words: natural hazards, landslide, entropy, folded Zagros.
 

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

 

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This study aimed to systematically explain the potential of the landslide occurrence to provide a prediction model of the possibility of this phenomenon in the Yamchi catchment in Ardebil province. In this regard, both approaches of discrete and continuous variables were used by means of overlay and logistic regression, respectively. Independent variables included elevation, slope, aspect, lithology, annual rainfall, roughness, general curvature, topographic wetness index, vegetation index, distance to fault, distance to stream and distance to road. The results, firstly, revealed the areas with high landslide potential by the matching layers of independent variables with the landslide layer in the geographical information system (GIS). These areas were in the middle elevation, high slopes, northern slope, high roughness, erodible formations, high rainfall, medium vegetation, surroundings of faults and rivers. Secondly, the results of the logistics regression model by providing a prediction equation of probability of landslide occurrence showed that the resulting model with pseudo r² and ROC 0.22 and 0.86, respectively, had good power and efficiency to predict landslide through the catchment. In addition, the resulting beta coefficients for independent variables indicated that the importance of the variables was as follows: vegetation index distance to road, rain, lithology, distance to fault, elevation, topographic wetness index, roughness index, aspect, slope, and distance to river. In the end, the need to pay serious attention to the supporting and protection of vegetation cover of the mid -range and upstream of the catchment was determined because of unstable geomorphic conditions of these areas.