risk zoning

Avalanche is one of the dangerous phenomena in snowy areas. Haraz mountain road is one of the most dense communication axes in the north of the country, and due to special geomorphological conditions, parts of its route are at risk of avalanches. So that since the beginning of the construction of this road, it has led to many financial and human losses. Therefore, it is known as the most news-making road in Iran. The purpose of this thesis is to identify the factors influencing the formation of avalanches and to identify the places where they occur, as well as to prepare an avalanche risk zoning map in the region with the help of geographic information system (GIS) and remote sensing (RS). In order to achieve the goal of the research, GIS software was used to draw maps of elevation classes (hypsometry), the amount and direction of the slope of the domain, geomorphology and other related maps. Then, by examining the relevant information sources, scoring tables of the effective factors of avalanches were formed. These tables include 5 main criteria (amount of slope, direction of slope, height, temperature and precipitation). Each of them is divided into indicators and the corresponding points are listed according to the type of factor and the degree of influence in the occurrence of avalanches. By combining the said information in the form of Bolean model, weighted according to the degree of their influence, and combining these layers together, the avalanche risk zoning map of the studied area was prepared, and finally, the results obtained from the maps were compared with the control results. The field was compared.

The results of studies conducted in this region show that the climate of the region is semi-arid and cold, and its rainfall regime is in the Mediterranean. Its geomorphology is young and its topography is directly related to geological structures, i.e., most folds and fractures make up the heights. The lithology of the formation, along with the action of tectonic processes that have led to the dissolution and creation of joints and cracks in the rocks, has provided the necessary conditions for the formation of less developed karst forms. The region's most significant karst forms are Karen, pinnacles, channels, dissolution doline and dissolution cavities, karst springs, and caves that have spread along joints, cracks, and faults and indicate the connection between these landforms and the region's tectonic structures. In this study, to find out the relationship between tectonics and karst formation, the dip and strikes of fractures (joints and faults) were measured in 7 areas. The results obtained from field studies and their comparison with the information contained in remote sensing documents show that the direction of most joints in the region is consistent with the direction of faults. It has also been found that more Karst landforms have formed along these joints. On the other hand, most of the valleys are consistent with the geological structures of the region, i.e., faults and folds. Therefore, tectonics has played an effective role in creating Karst landforms and their hazards in the region. According to the rockfall risk zoning map, 3.77% of the total area is in the high-risk zone.

Floods can have various causes. One of the new and challenging reasons of the 21st century is the issue of land use changes, a detailed examination of the set of environmental factors that are the cause of these incidents shows that human intervention in the natural water cycle through vegetation in watershed areas, Urban development and industrialization of communities have adverse effects on the hydrology of the catchment basin and cause intensification of floods, increase of pollution in the catchment area, reduction of base flows and reduction of underground water supply. Flood is one of the complex and destructive natural phenomena that causes a lot of damage every year. In order to plan for the optimal use and control of natural flood phenomena, which is one of the issues in the world, including our country, many studies and researches are needed.For this purpose, the purpose of this research was to investigate the situation of Mehr city located in the south of Fars province, in terms of flooding and risk zoning due to this important natural disaster. This survey was done in a descriptive-analytical way and in order to predict the extent of damages caused by floods. The required data was collected in this regard. The collected data were weighted after correction and transformation, and after performing pairwise comparisons and determining the final coefficients of each layer, the required maps were prepared. AHP model and relevant software, especially Choice Export, ArcGIS, etc., were used to determine the weight and final coefficients.

Karst aquifers in semi-arid regions play a vital role in people's lives. Therefore, recognizing the pollution potential of aquifers and their vulnerability in different sectors is very important. The western region of Iran, due to the expansion of the Zagros carbonate mountain range, has numerous karstic aquifers that are exposed to pollution in terms of environmental conditions and extensive human activities. The purpose of this study is to estimate the vulnerability map of Aleshtar plain karst aquifer located in Lorestan province against COP pollution. This model evaluates the vulnerability of karst water sources to pollution using three factors, cover layer (O), flow concentration (C) and precipitation regime (P). The results show that 19.14, 28.76, 35.01 and 17.09% of the area are located in very low, low, medium and high vulnerability zones, respectively, which indicates the almost low vulnerability of this karst aquifer compared to It is pollution. Findings indicate that the importance of the overlay factor, precipitation regime factor and flow concentration factor in the pollution of Aleshtar aquifer, respectively. Due to the small area of ​​fully developed karsts and the high slope of areas with developed karst, the role of flow concentration factor in pollution of Aleshtar aquifer is less and due to the drought trend of recent decades and the change of precipitation from snow to rain showers that water retention and therefore less penetration In the karst basin of Alshtar, the importance of the rainfall regime in the vulnerability of the Alshtar aquifer has decreased. Finally, due to the high permeability of the alluvial plain of Aleshtar, the cover layer has provided the ground for aquifer pollution. In general, in the study area, C, P and O, respectively, have the most role in the vulnerability of the area.

As one of the largest ports in southern Iran,MahshahrPort faces the risk of seawater intrusion from Mahshahr estuary. Mahshahr and Mousa estuary form an 86 kilometerwaterway. Midday mixed tide is dominant throughout this waterway. Moving towards the vertex of the estuary, this dominance of the midday tidebecomes much more evident. Considering an average depth of 38.4 m, midday tidal wave of M2 with an approximate wavelength of 860 km can be reinforced in this waterway. Grounding of boats and otherammunitions in the basin of Mahshahr port (betweenMajidiyeh garrison and the Persian Gulf) was one of the most important issues during the Imposed War.Mahshahrestuary is the only possible way to access the Persian Gulf fromImam Khomeini port and Majidiyehnaval garrison. From a military perspective,Mahshahrestuary has a special feature that can be considered as a strategic factor and used in various types of active and passive defense. In spite of the shallowness of its internal parts,it is considered to be a safe haven for small vesselsin times of crisis and air attacks. Sometimes, it is critical to use these estuaries and their navigable waterways as the main route for transportation of military weapons, medical aid, and rescue services. Crisis managers and urban planners need an appropriate plan based on risk map of the study areato reduce the risk of tidal process. However, zoning tidal process and mapping its risk are not enough by their own: a useful system needs toidentify sensitive and vulnerable pointsto increase the efficiency of tide risk zoning.

Seeking to reduce the risk of tidal process,the present study determinesmaximum level of development in areas covered during high tides usingHecgeoras software. In order to achieve the goals, hydrographic data of the substrate was used along with information and statistics received from high accuracy hydrometric stations. This zonesurrounds an area of around 944 hectares. Field visits indicate thatduring tidal process, soil conditions in the study area hampers sending emergency aids using land routes.Considering the conditions and structures inMahshahr estuary and the tide zone in the study area, investigating geology of the study area seems necessary.

Considering the soil conditions in the study area, the highest level of soil flooding was observed during high tide. This increasessoil adhesion, affects water intrusion, and hampers sending aids. Critical areas in danger of water intrusion from the estuary (such as Mahshahr gas reservoirs and Majidieh military garrison) were identified in the present study. Moreover, results were investigated and land visits were performed to present accurate and reliable results. Land visits were carried out during 2016-2017 winter and 2017 summer in order to achieve better and more accurate results based on the climatic changes. Investigating the recorded level of water in the study area shows up to 3-metervariation in the water level of Mahshahr estuary. Necessary decisions regardingthe use of different types of vessels, and passive/active defenses can be made in accordance with water level fluctuations and specified times for each water level. During local visits performed for quantitative analysis of results, soil type and its role in passive defense were also discussed.

Field studies and observations in the study area indicated that 1) dominant soil type of the region is a highly adhesive type with a high clay content; 2) during tide time, soil flooding results in increased adhesion of soil and practically hampers movements of ammunition; 3) In summer and winter, water level changes repeatedly and thus, necessary measures shall be considered for military programs in accordance with the time in which water fluctuations occur. Although the depth of water in the study area is significant, it should be noted that Mahshahr estuary finally reaches an urban area, and thus can be used for military actions. In fact, mapping tide zone is a very effective method for reducing the risk of tidal process in coastal areas.

Faults are among the most common geological conditions in rock masses, which are considered as one of the most significant examples of rock discontinuity. The earth’s instability is often due to the presence of faults in or near them. Bozqush Mountains are the most important landscapes in southern Azerbaijan, including the south-western border of Tabriz fault’s extension, and south-eastern border of Mianeh-Ardebil fault. Benaravan fault in the eastern part of this mountain range is part of the Mianeh-Ardabil fault. In the present study, a study was conducted titled as Zoning the Risk of Hillside Instability Using Artificial Neural Network with MLP Model. This was the purpose of selecting this model to investigate areas with the potential of hillside instability occurrence.
Data and Methodology: In this study, aerial photos and ETM satellite images of the region, topographic maps with a scale of 25000/1, and geological map with a scale of 100000/1 were used. There were also several field visits to the area.
Artificial Neural Networks Model: Neural network models are a kind of simplistic modeling of real neural systems that are used extensively in solving various problems in science. The best way to solve complex problems is to break it down into a simpler sub-question, and each of these sub-sections can be easily understood and described. In fact, the network is a collection of these simple structures that together describe the ultimate complex system. It must be pointed out that in this study, a variety of multilayer perceptron networks were used.
Data Analysis: To investigate the relationship between the factors affecting the occurrence of hillside instabilities in the studied area, after providing dispersion map of instability points, the dispersion of these points to nine factors affecting the occurrence of hillside instabilities was investigated. Each information layer was classified into five classes, and based on the degree of sensitivity to hillside instabilities, each of the rating classes was given a score between 1 to 5. 5 was given to a class that had the greatest hillside instability.
The Argument and the Findings: The maps of the factors affecting the hillside instability, which are independent variables in the instability occurrence, were entered into IDRISI software and were processed. In constructing an artificial neural network, the first task is to determine the type of the network. In this study, an artificial neural network with a multi-layer perceptron structure (MLP) with 1 input layer, including 9 neurons, and a hidden layer with 16 neurons, and an outlet layer were used. The algorithm used in this network was the same after error algorithm, and the sigmoid function was used as an activity function. In order to achieve better zoning and proper output with high precision, a different structure of the neural network was tested by changing the number of neurons and other parameters. This optimal number was achieved at 20000th recurrence with a training error of 440/0 and a test error of 0.0622. As stated, the best way for an appropriate network architecture is achieved through trial and error. In this study, using the trial and error method, the best architecture was selected with 1 input layer including 9 neurons, a hidden layer including 16 neurons, and an output layer (9,16,1). The study used 3181 sliding pixels data for network training and testing. Of these pixels, 2544 pixels were used for training and 636 pixels for network testing. Multiple training rates and momentum factors were tested, and finally, the training rates between 0.014-0.01 with amounts and momentum factors of 0.5 were selected. After performing the above steps, using neural network method, the zoning map of hillside instabilities occurrence risk was prepared,
When a hillside is liable to instability, the occurrence of instability at its surface will be inevitable. Theoretically, if steep hillsides that are formed by loose and detached materials, get adequate moisture or water, they are prone to instability. Then, if one or more secondary factors interfere, the instability will occur. Heavy rainfall, movement of faults, earthquake, Earth’s roughness and so on are among such factors. Given these cases, the likelihood of hillside instabilities occurrence in an area, in case of occurrence conditions, is expected. For zoning hillside instabilities occurrence risk using artificial neural network, first at the testing stage, in order to avoid error increase and over-training of the network, each of the parameters of the artificial neural network was determined by trial and error. In this study, a network with an architecture of an input layer with 9 neurons including categories as altitude, gradient, gradient direction, lithology, distance from fault, distance from canal, distance from road, land use, vegetation, and an intermediate layer with 16 neurons and an output layer (9,16,1) that shows areas with potential for the occurrence of hillside instability, was used. The results showed that 81.5%, 95.12%, 38.19%, 06.27%, and 78.34% of the area were located in very high, high, medium, low and very low risk groups, respectively. The zoning map of hillside instability risk shows that areas with high and very high risk, cover about 76.18% of the study area, which are more consistent with the high altitudes, fault zone, and high gradient of the area.