Search published articles


Showing 3 results for mozafari

Dr Sayyad Asghari, Hasan Mozafari,
Volume 6, Issue 4 (2-2020)
Abstract

Evaluating and comparing the performance of Frequency ratio coefficient models and network analysis in Rock fall zoning
(A case study of Zanjan-Taham-Tarom Road)

Extended Abstract
One of the natural hazards of the collapse of rocks from the foothills of the mountains, causing great financial losses and loss of life. Especially when it comes to the path of communication. The rock fall is a rapid movement of a mass without cohesion in the powder or a mixture of soil and rock, so that the initial construction is not discernible, the level that occurs along that rupture it is often unclear. The falling stones of a mountain depend on several factors, which have the natural origin or origin of human origin. Natural factors influencing the fall can be rock factors, slopes and altitudes, geological structure, fault and slope of the geological layers, rainfall and temperature changes distance from the river, etc. human factors can also be referred to as road, land use and mining, destruction of vegetation, etc. in Iran, the collapse of rock parts on mountain roads causes massive loss of life and financial damage. Therefore, it is necessary to identify and classify the roads in terms of risk of suitable methods. In the north west of Iran it has mountainous topography and due to the state of tectonic and its seismic and climatic conditions, suitable conditions for landslide are provided in some domains. So, due to the fact that the area studied in the mountainous north - west region and the possession of all the crumbling conditions are very prone to collapse.
The research method is applicable in terms of practical purpose and the process of doing work on a combination of library and field methods. In this study, it has been used to determine the prone areas of collapse and zoning of anp models and frequency ratio. Two models that differ in terms of process and mechanism. In order to organize the research framework, first, a field study of the study area has been studied and the mathematical position of falling points is recorded with gps. Then, in order to model the mentioned models, the layers of GIs for the shape of the Georeferenced and digital were prepared. to provide the zoning layers of geology , slope and Aspect , elevation levels , land use and vegetation , fault , and land cover maps , annual temperature and precipitation , distance from the road , distance from the stream were used . The 20 m x 20 m contour line were originally prepared using the topography map of 1: 25,000 in the ArcGIS environment. Then, the contour line and Dem of the area were constructed. The slope and Aspect maps, elevation levels, Isothermal and isohyet map frost and stream network were created via Dem and meteorological data. Geological map and fault map were created using digital map 1: 100,000 Zanjan and map and vegetation map and road distance using Landsat 8 - 2017 OLI and ArcGIS images. To produce linear layers, the Distance function was used.
Using the statistical method, the frequency ratio and the network analysis method are using the landslide hazard zonation using the statistical method, the frequency ratio and analysis of network analysis to zoning the risk of falling by combination and sum of maps in class were low-risk to very high. From the tangible results of this study, the relationship between slope maps, elevation levels, rock material, Isothermal and isohyet is done. So that each side of the road had operated on the five factors that had happened. With regard to the output of the maps, the risk zones were high to very high for ANP models 14/17, 35/27 and FR 02/6, 35/14 percent. Ranges from high to very high with slopes between 40 and 80 percent and Sedimentary formations such as sandstone, siltstone with tuff layers, elevation levels 1,500 – 2300, Southern and Eastern slopes, Distance between 0 and 500 faults, Road and stream have adaptations . The changes in the percentage of area in both models show despite the difference in the size of the risk zones, Follow a similar process. To assess the zoning accuracy of these methods, two sets of quality and accuracy index (experimental probability) were used. The evaluation of the models showed that in the network analysis model, the indexes were 0.76 and 0.88, respectively, that the relation of frequency ratio coefficient model had optimal quality and accuracy.
In this research, various factors influencing the occurrence of rock falls on Zanjan-Taham-Tarom road were investigated. From there, mass movements such as rock fall on the roads act as a system, as a result, all factors play a role in the occurrence of such phenomena. But some elements have a more vibrant role. In the studied area, among the factors affecting lithology, slop, elevation levels, precipitation, temperature changes, number of freezing days and distance from the road and land use are more than other factors in the occurrence of rock fall. Assessing the quality and accuracy of zoning maps while confirming zoning accuracy showed that the network analysis method has better performance. The risk of collapse on Zanjan – taham- tarom road is always exists. Therefore, we need to use sustainable methods to reduce the risks. Domain stabilization methods are generally done in the form of mechanical, biological and bio-mechanical which, according to the long course of the road and the duration of the road, Mechanical methods such as unloading , embankment , drainage , use of separation walls as well as the use of  net Grid are suggested .
 
Keywords: Frequency ratio, Network analysis, Zanjan Road - Taham - Tarom
 
.


Masoomeh Hashemi, Ezatallah Ghanavati, Ali Ahmadabadi, Oveis Torabi, Abdollah Mozafari,
Volume 8, Issue 4 (1-2021)
Abstract

Earthquakes as one of the most important natural disasters on earth, have always caused irreparable damage to human settlements in a short period of time. Severe earthquakes have led to the idea of developing an infrastructure plan to reduce the risks and damages caused by it. The urban water supply system is the most important critical infrastructure that is usually damaged by natural disasters, particularly earthquakes and floods; hence, the function of the pipelines of the water system determines the degree of resilience and design of the infrastructure against multiple natural and man-made hazards. Water network pipelines are the most vulnerable. In this regard, seismic modeling and spatial analysis of the effects of seismic urban water supply network in Tehran were investigated and seismic indices PGV, PGD.PGA of Tehran were calculated and the extent of the area's vulnerability was carefully evaluated. The ANP model was also used to weight the above indices. Questionnaires were prepared and completed by experts in the field of research in order to investigate the interactions between the criteria in terms of their effectiveness or susceptibility. The ANP conceptual model was developed and implemented in SUPER DECISION software. After drawing the hazard status, the calculation of the water supply network vulnerability using SAW method was considered and earthquake risk status on the water supply network was calculated. To calculate the earthquake risk based on R = H * V, the values of these two components (seismic power, vulnerability) are multiplied. This calculation was performed in GIS software on the layers of vulnerability and the final result of this calculation was shown in the amount of risk map. The calculated risk level for the entire water transmission network due to earthquakes has been shown. The results show that more than half of the transmission line network is located in the low risk zone and about 33 percent of transmission networks are in a relatively low risk zone. But high-risk and very high-risk areas account for about 20 percent of Tehran's total area, which is relatively large and will involve many neighborhoods
Masoomeh Hashemi, Ezatallah Ghanavati, Ali Ahmadabadi, Oveis Torabi, Abdollah Mozafari,
Volume 10, Issue 2 (9-2023)
Abstract

Introduction
Earthquakes as one of the most important natural disasters on earth, have always caused irreparable damage to human settlements in a short period of time. Severe earthquakes have led to the idea of developing an infrastructure plan to reduce the risks and damages caused by it. The urban water supply system is the most important critical infrastructure that is usually damaged by natural disasters, particularly earthquakes and floods; hence, the function of the pipelines of the water system determines the degree of resilience and design of the infrastructure against multiple natural and man-made hazards. Considering the inability to prevent earthquakes and the inability of experts to accurately predict the time it is necessary to know the status of earthquake-structure and seismicity in Tehran to determine the amount of earthquake risk in order to make the necessary planning for structural reinforcement. Theoretical and field studies of tectonic seismicity in the Tehran area show that this city is located on an earthquake-prone area around the active and important faults of Masha, north of Tehran, Rey and Kahrizak. The occurrence of 20 relatively severe earthquakes illustrates this claim. Regarding the location of faults in Tehran city, it is necessary to assess the vulnerability of Tehran water facilities.
Research Methodology
The present study is a practical-analytic one. Considering the severity of earthquake damages, it is necessary to conduct earthquake hazard zonation studies in different urban areas and to determine important indicators of damage assessment such as maximum ground acceleration, maximum ground speed, maximum ground displacement. Three indices were considered for mapping earthquake seismic zones and their integration into the GIS presented a seismic hazard map. In the analysis of earthquake risk, it is necessary to evaluate two indicators of risk and vulnerability. To prepare the general hazard power mapping the weights obtained from the ANP model were applied to the existing raster layers via the Raster Calculator command. In this way, the standardized layers are multiplied separately by their respective weights and finally overlapped. In order to evaluate the vulnerability, a series of evaluation indices are introduced and ANP techniques are used. The relative value of each index is then calculated using the multivariate approach using the SAW technique. In order to calculate the earthquake risk based on R = H * V relation, the values ​​of these two components were multiplied. This calculation was performed in GIS software on the risk and vulnerability raster layer and the final result of this calculation was displayed on the map.
Description and interpretation of results
In this study, we tried to estimate the relative risk and risk of seismic hazard on the water supply lines in Tehran, using available data and scientific methods, and map the risk level. These lines should be prepared first by the amount of earthquake hazard risk and then by the risk map, to estimate the earthquake risk on the water supply network. first the earthquake risk then the status of the hazard lines should be calculated. The vulnerability of the water supply lines was calculated using the ANP model by multiplying the total potential hazard risk then substrate transfer network vulnerability risk map obtained transmission network. The highest risk was in the west and north of Tehran. The maps showed the risk potential and the vulnerability of the lines. These areas had high seismic potential and the density of the lines was higher in these areas. Water transmission facilities are at risk and earthquake hazards may be affected by damage to the transmission lines, drinking water to a large population will be difficult, as well as performing necessary zoning to prevent future expansion of the facility in place. These analyzes are a prelude to applying corrective techniques to pipelines to reduce their vulnerability and prevent newly created pipelines from locating in vulnerable areas. Since the results of this study are risk maps along the route of the water supply lines, so in order to prepare a risk control program, we can identify the high risk pipeline map and identify the pipeline vulnerability. And, depending on its location, provided an appropriate prevention and control plan for the conditions surrounding the pipeline environment.


Page 1 from 1     

© 2024 CC BY-NC 4.0 | Journal of Spatial Analysis Environmental hazarts

Designed & Developed by : Yektaweb