خيارات البحث
النتائج 71 - 80 من 297
Examining the Vulnerability of Urban Areas to Earthquake Risk Based on the IHWP Model: The Case Study of District 6 of Ahvaz Metropolis
2022
Parvizian, Alireza | Maleki, Saeed
The disasters of recent years indicate that communities and individuals are getting increasingly vulnerable and risks are progressively growing. Nonetheless, the need to reduce risks and vulnerabilities are often ignored up until the occurrence of disasters. In the study at hand, which was done based on the descriptive-analytical method, it was tried to examine and predict the vulnerability perspective of the areas located within District six of Ahvaz metropolis during a potential earthquake based on the main purpose of this study. The theoretical data of the study was collected through library research method. After the extraction of the related indices, the spatial analysis of each index was carried out through fuzzy Delphi method, IHWP vulnerability model, and GIS software analyses. The analysis of the findings illustrated that considering the first and second priorities of the crises management, 15.03 percent of all areas of the district under study are highly vulnerable to earthquake. That is to say, in case of a strong earthquake in the district, they will be vulnerable. The study concluded that the physical qualities of the building are as important as the factors such as land use, population density, and time of earthquake occurrence. These have all effective roles in the vulnerability rate and the rescue activities.
اظهر المزيد [+] اقل [-]An Analysis of the Vulnerability of Tehran Urban Blocks to Earthquake Via Designing and Implementing a Location-Base Model
2022
Afsari, Rasoul | Nadizadeh Shorabeh, Saman
The vulnerability appraisal is one of the prerequisites of risk analysis in disaster management. Vulnerability to earthquake, especially in urban areas, has increased over years due to the existence of complex urban structures and rapid development. In order to take preemptive measures and reduce the damages of earthquake, the determination of vulnerable areas and implementation of necessary measures seem inevitable. Accordingly, the present study set out to examine the vulnerability of Tehran urban blocks via a location-base model. To attain this objective, first the criteria effective on the evaluation of earthquake vulnerability were divided into three groups, namely exposure, sensitivity, and adaptation capability (16 location criteria in general). Using the expert opinions and network analysis model, the importance of each of the criteria was determined. Fuzzy functions and ordered weighted averaging method were used to normalize the criteria map and develop vulnerability maps under various scenarios. Finally, the sensitivity analysis of the criteria was carried out. The results showed that vulnerable population density and average slope were the criteria with the most and least importance, respectively. The vulnerability maps demonstrated that the areas to the north of the area under study are in the vulnerable class under all scenarios. The stability and dependability of the output results were assessed using sensitivity analysis. The results indicated that changing the weight of the criteria does not have a significant effect on the model outputs, a finding that clearly proves the stability of the model.
اظهر المزيد [+] اقل [-]Assessment of Shahre Rey Fragmentation Trend Using Metrics
2021
Foroutan, Sara | Shariat, Mahmoud | Kheirkhah Zarkesh, Mir Masoud | Sarvar, Rahim
Land use in Shahre Rey has experienced unprecedented growth in urban areas in recent decades. Land use changes affect social, economic, and environmental conditions. Gathering information about these changes is essential for better planning and management of urban areas in sustainable development. Consequently, the object of this paper is to better examine the Shahre Rey land use changes affected by urban development and to investigate urban landscape integrity using the 1988-2018 "Fragmentation" index. Moreover, it was intended to provide solutions for the determination of hot spots based on appropriate criteria. With the help of Landsat satellite images, four land uses – including urban landscapes, agricultural lands, green spaces, and barren lands – were extracted and the extent of land use changes was determined. In order to investigate the fragmentation of Shahre Rey landscape, the metrics of the number of patches, patch density, and the largest patch were used. Cross-Tab was also used in a part of the study. The results showed that the land use areas of urban lands and urban green space had increased by 369.7 and 55.6 hectares, respectively, while agricultural lands and barren lands had decreased by 213.8 and 211.5 hectares, respectively. In urban land use, integration had increased. In the green space and agriculture land uses, fragmentation has increased due to the creation and construction of roads. Based on the criteria of "position relative to borders and roads as well as the area and size of patches,'' solutions were made to determine the "hot spots" of vegetation and residential areas to help making plans for the improvement of their conditions. The reason is that land use change, especially the loss of vegetation, has a negative impact on the landscape.
اظهر المزيد [+] اقل [-]Spatial Analysis of the Factors Effective on Flood Occurrence in Ilam City
2021
Tahmasebi, Qobad | Mohammadi, Alireza | Bouchani, Mohammad Hossein
The topic of climate change and the dangers that lie ahead is part of the debate in land management. The dynamics of global change and the sovereign approach of global governments have opened new perspectives on land management issues. One of the hidden challenges in this regard is the increasing risk of the occurrence of floods. The purpose of this study was to undertake metric or measurement model as a spatial basis unit to predict flood occurrence. In the present article, in line with using MikeUrban 2019 software, a wide range of tools and quantitative processing steps were used in accordance with the research objectives. In order to predict floods, the past incident factors were studied, namely a review of the principles and operational indicators related to each parcel using the OLI sensor images of Landsat 8 satellite in the year 2020 through the integrated interpretation method and an examination of the basic map of Ilam city in wet seasons (autumn, winter, and spring). Then, the city coverage map was prepared in two uses, i.e., False Color (Urban) and Land / Water. Next, Google Earth images were used to determine the accuracy and precision of the coverage maps. By combining four selected measures with the highest spatial correlation in 50 random points of the city, hexagonal measures with optimal areas were selected and spatial patterns were analyzed. According to the results, in the actual event (1), eight spatial measures with an area of 68 hectares and coverage of 1.5% of the entire city are at risk of flood. In events 0.8 and 0.9, 19 measures with an area of 170 hectares, 3.6% of the land use coverage of the area, are at potential risk. While there is a high correlation between flood event and type of measure, amount and direction of slope, as well as density and width of road network on one side and drainage network on the other side, in high events (1-8), 28 measures in the residential uses in the detailed design scale with an area of 76.5 hectares, barren and enclosed uses with an area of 70.55 hectares, roads network with an area of 29.75 hectares, and parks and green spaces with 17 hectares were identified as the uses targeted by the flood danger. Among all risky user groups, 29.5% were identified in the newly built group, 44.5% in the maintainable group, and 18% in the decayed urban environment group.
اظهر المزيد [+] اقل [-]An Analysis of the Reasons for the Decline of the Position of Tabriz Metropolis in the Urban System of Iran and the Prediction of its Population and Position by 2031
2021
Ghorbani, Rasoul | Alizadeh, Hooshmand | Karami, Sonya
Demographic changes in recent decades have led to rapid changes in Iran's urban system and its hierarchy, with one of its consequences being the increase or decrease in the ranking of cities in this system. The present study examines the position of Tabriz metropolis in the urban system of Iran from 1335 to 1395, and by forecasting the population of this metropolis by 2031, it tries to determine the future position of this city in the urban system of Iran. This study is practical in terms of purpose and descriptive-analytical in terms of nature and research method. The data in the present study were obtained through document analysis and field study (questionnaire and interview). Interviews were used to understand the causes of emigration and a questionnaire was used to understand the causes of fertility decline in Tabriz metropolis. The sample sizes for both instruments were determined based on the saturation principle. The exponential model, Spectrum software, and rank mobility index were used to predict the demographic factors, population forecast, and the study of metropolitan rank changes in the urban system, respectively. The obtained results showed that the decrease in fertility rate and migration are the main reasons for the sharp decline in population growth in the metropolis of Tabriz, with the economic reasons being the main reason. In addition, assuming the fertility rates of 1.5, 1.8, and 2.1 in Tabriz, we will see 1.64, 1.69, and 1.74 million increases in the population of the city, respectively, as well as a decrease in the population of minors and a doubling of elderly population over 65 by the year 2031. The results of population forecast show that the position of Tabriz metropolis will be stabilized as the sixth largest city of Iran's urban system by 2031, but its distance from the seventh metropolis (Qom) will be less, which requires special attention and proper management to prevent its rank from falling again.
اظهر المزيد [+] اقل [-]The Management and Planning of Kangavar Geographical Area for Agricultural and Rangeland Uses
2021
Rahmanabadi, Hassan | Hossein Zadeh, Mohammad Mehdi | Mirbagheri, Babak
The assessment of the ecological potential of the environment is to determine and measure the potential power and the natural use type of the land. Therefore, the environment power assessment is a tool for the management of geographical space and strategic planning for sustainable development and correct use of land sources. The aim of this study was to evaluate the ecological potential of agricultural and rangeland use in Kangavar city with an area of 883.9 km2 using Makhdoom ecological model. To this end, the required data and ecological resources were collected and generated. After creating and combining the maps in the ArcGIS system in a multi-hybrid way, the maps of environmental units were constructed and the ecological potential of the area was evaluated using the features of each environmental unit. To do this, the indicators and variables that could be involved in each of these models were examined. To classify the ecological potential of the area for agricultural and rangeland uses and to produce the map of different classes potential, 15 parameters were used as criteria for weighting and measuring the power. The results of Kangavar city ecological potential assessment led to the extraction of 58 environmental units in 7 classes with completely suitable, suitable, weak, and unsuitable power classes for agricultural and rangeland use. An area of about 356.79 Km2 was found to have suitable and completely suitable power for agricultural use. In addition, it was estimated that an area of about 72.23 Km2 would be appropriate for rangeland and rainfed agricultural use with suitable power. An area of about 483.26 Km2 of Kangavar city is currently allocated to agricultural use, while the optimal area for this means is 356.79 Km2. Thus, the land use of an area of about 126.47 Km2 has been converted to agricultural purposes. According to the results, the lands of the region have been exploited more than their potential for agricultural use (irrigated and rainfed) and the lands with rangeland use have been changed to agricultural use.
اظهر المزيد [+] اقل [-]The Evaluation and Modeling of the Impacts of Urban Development on Landscape Patterns in Karaj Metropolis
2021
Mohammadyari, Fatemeh | Mirsanjari, Mir Mehrdad | Zarandian, Ardavan
The goals of the present study were to analyze changes in land cover and to estimate a future scenario for 2028 using an artificial neural network in the Karaj Metropolis. To this end, the effects of land use changes in response to urban expansion on landscape patterns were investigated in three baseline, current, and future scenarios using landscape metrics and gradient analysis. The results showed that during a 22-year period, the agricultural and Garden lands have been severely damaged due to urban expansion. The results of the evaluation of changes in landscape also indicate that urban expansion in in development in the north-south transect to the margins (especially northward) and the east-west transect with a gentle slope to the west of the region. It is also anticipated that in the future scenario, if the current trend continues, the northern margin of Karaj metropolis will be changed from natural environment to a completely human-made one. Therefore, considering the results of the Pd and Ed metrics in both transects over the three examined years, it can be said that the area has expanded to the margin and there has not been much changes in the landscape of downtown. In addition, the decrease in the Pd and NP in all three scenarios indicates the consistency of urban landscape. In general, population growth and urban development have made the landscape pattern in Karaj metropolis to be a more regular and less varied one. The results indicate that spatial heterogeneity has altered the landscape patterns. Therefore, the growth of construction land in some areas should be restricted, and balanced development should be adopted to prevent the fragmentation of the landscape.
اظهر المزيد [+] اقل [-]Modeling the Process of Spatio-Temporal Changes in Land-Use and Urban Development of Ahvaz Based on Spatial Planning Approach
2021
Abiyat, Mohammad | Abiyat, Mostefa | Abiyat, Morteza
The land-use changes and urban development are among the fundamental topics of spatial planning. Monitoring changes in previous years and predicting these changes in the coming years have a significant role in planning and organizing urban spaces. The purpose of this study was to investigate land-use change and urban development in Ahvaz with a landscaping approach based on balanced urban development. .Images of TM (1989), ETM+ (2002), and OLI (2019) of the Landsat satellite are the basis for analyzing this trend. LCM model was used to identify the past changes, while CA-Markov chain model was applied to predict the future changes. These images were classified using a support vector machine algorithm of the object-oriented method, and the land-use maps were prepared using three sensors with four classes of vegetation, barren areas, constructed areas, and water zones. The accuracy of maps was improved separately using NDVI and SAVI indexes in the classification of the images. The efficiency of the indexes was measure by kappa coefficients and the overall accuracy of land-use maps, and then changes were investigated using maps related to the superior index. The results showed that maps related to the SAVI index were more accurate and accordingly, they were used in assessing land-use changes. The LCM model showed that in the periods 1989-2002 and 2002-2019, 2602.92 hectares and 31174.77 hectares were added to the built areas, respectively. In both periods, the most changes were about converting barren lands to built-up areas and the least changes were related to the transformation of the built-up areas to water areas. The results of the CA-Markov model until 2029 showed the continuity of the increasing trend of built-up areas, such that in ten years, 2238.82 hectares will be added to the built-up areas, and it is anticipated that the area will reach approximately 12345.63 hectares by 2029.
اظهر المزيد [+] اقل [-]Drought Forecasting for Future Periods Using LARS-WG Model: The Case Study of Kermanshah City
2021
Heshmati, Sara | Ramezani Etedali, Hadi
The prediction of climactic changes is of great importance due to their destructive effects on aquatic, environmental, economic, and social resources. Accordingly, the purpose of this study was to predict the climactic changes of Kermanshah city using micro-scale general atmospheric circulation models accessible in LARS-WG6 (GFDL-CM3, MPI-ESM-MR, MIROC5) model in scenarios RCP4.5 and RCP8.5 for the 2020 to 2100 period based on the benchmark period of 1980-2010. In order to evaluate the data forecasted in LARS-WG model, the error rate of the observed and predicted data was addressed using R2, RMSE, MSE, and MAD criteria. The results showed that LARS-WG model had the needed capability to predict climactic data in future. In the secondary models, the MPI-ESM-MR model in scenario RCP4.5 showed a higher reliability rate compared to other secondary models evaluated in the study. Moreover, all models indicated increases in the average minimum and maximum temperature and forecasted changes in rainfall pattern in future periods in the studied area. Then, the SPI and De Martonne indices were calculated for all models. According to SPI index, all evaluated climactic models demonstrated that by the year 2100, the years with normal index would decrease while the years with dry conditions would increase. Moreover, based on De Martonne index, the GFDL model in RCP8.5 scenario estimated the climactic changes level more than other models, and predicted that dry and semi-dry years will be more than wet years. Contrarily, the MIRO model in RCP45 scenario acted more optimistically and predicted less climactic changes.
اظهر المزيد [+] اقل [-]Modeling of Ecosystem Services based on Land Cover Change and Land Use Using InVEST Software in Jahannama Conservation Area (Case: Carbon Sequestration Ecosystem Service)
2020
Fadaei, Ensiyeh | Mirsanjari, Mir Mehrdad | Amiri, Mohammad Javad
Several benefits that humans get from ecosystems are called ecosystem services. Carbon sequestration as an eco- regulation service is declining, due to the transformation and destruction of the earth used to recompense the burgeoning human needs for development. In the present study, a pilot landscape of hyrcanian forests, protected area in Jahannama was selected. By examining the land use / cover changes during 2001 to 2018, future condition of the land will be set to determine the carbon storage and carbon sequestration model in 2036. The amount of carbon in the four carbon storage sources including biomass, underground biomass, soil and organic matter along with IPCC reports facilities, field studies and sampling was extracted. Deterioration trend in forest lands and grassland with remarkable role in carbon sequestration was sharpened. The reduction trend will be predicted to reach as much as 40 per cent which will be equivalent to 400859 tons per land. With the same rate in land deterioration, a considerable decrease in ecosystem storage and carbon sequestration’ potentiality will be expected present study indicated that the integration of the concept of the ecosystem services in land planning discourse and land use management via the provision of spatial maps of ecosystem services on a regional scale, along with the rational development of human use, ecological hazards should be minimized, as a result better decision will be made in planning the land. It is also suggested that to enhance the quality of Jahannama ecosystem services in development plans and review within the protected boundaries and the principled management of land use within the protective boundaries.
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