وضعیت تراکم در شهرهای بزرگ از جمله اصفهان، با افزایش جمعیت و بدون توجه به آثار اجتماعی، اقتصادی، فضایی - کالبدی و زیبایی شناختی، مسایل و مشکلاتی را به وجود آورده که توجه برنامه ریزان شهری را به خود جلب کرده است. پژوهش حاضر به دنبال دستیابی به یک الگوی منطقی از تراکم ( کاربری، ارتفاعی و جمعیتی ) در شهر اصفهان و تأثیر آن بر آسیب پذیری ناشی از زلزله با رویکرد فازی صورت گرفته است. پژوهش از نوع کاربردی، روش پژوهش بر اساس مدل استنتاج فازی و روش جمع آوری دادهها به صورت اسنادی است. اهداف این پژوهش، شامل؛ شناسایی وضعیت تراکم جمعیتی، تراکم کاربری و تراکم ارتفاعی ( ساختمانی ) در مناطق شهر اصفهان و کشف ارتباط بین میزان تراکمهای شهری و آسیب پذیری ناشی از زلزله در شهر اصفهان است. نتایج حاصل از پژوهش نشان میدهد که در بررسی وضعیت تراکم شهری، در نظر گرفتن رابطه بین سه نوع تراکم جمعیتی، ارتفاعی و کاربری الزامی است. همچنین، رویکرد فازی در نرمال سازی دادههای مربوط به تراکمهای شهری، یکی از بهترین رویکردها محسوب میشود. بیشترین ضریب در بخش آسیب پذیری لرزه ای به ترتیب مربوط به تراکمهای کاربری و جمعیتی است؛ به عبارت دیگر، ادامه روند فشردگی شهر در مناطق خاص و نیز گرایش شهروندان به سکونت در همان مناطق، بدون توجه به توزیع متعادل، میزان آسیب پذیری لرزه ای را افزایش میدهد. در نهایت، مناطق 1 و 6 شهر اصفهان به ترتیب بالاترین میانگین رتبه تراکم را دارند؛ به عبارت دیگر، عمده تراکمهای جمعیتی، کاربری و ارتفاعی در این مناطق است.
عنوان مقاله [English]
A Survey of Density Effect on the Vulnerability of Earthquake in Isfahan City (Fuzzy Approach)
Â A Survey of Density Effect on the Vulnerability of Earthquake in Isfahan City (Fuzzy Approach) Â Â Â S. Ghaedrahmati. ( * ),Â Assistant Professor of Geography and Urban Planning, Yazd University, Yazd, Iran. Â email: email@example.com Â Â Â I. Bastanifar.Â PhD student in economics, University of Isfahan, Isfahan, Iran. Â Â Â L. Soltani .Â PhD student in Geography and Urban Planning, University of Isfahan, Isfahan, Iran. Â Received: 15 May 2009 / Accepted: 13 October 2010, 31-34 P Â Â Â Extended Abstract Â 1- Introduction Â For few decades, the population of cities in developing countries, including Iran had a higher growth rate than the total growth rate of countriesâ population. The cities in the developing countries have become areas of very high vulnerability to natural hazards such as earthquake. Analysis of urban density using statistical data has a crucial role in the urban geographic studies and urban planning. Based on studying type urban density can be measured by different models. While in developed countries, the development of the big cities began centuries ago and generally allows for Â Â Â controlled and planned urban density, the opposite is the case in developing countries, where rapid urbanization's process is characterized by an unplanned urban density. The developing metropolitan cities have enormous difficulties in coping both with the natural population increase and the urban physical expansion. In fact, urbanization process increases the vulnerability through centralization of human and property. Because of unplanned urbanization, growth of land in vulnerable areas with a high level of hazard risk, inadequate urban management and unsuitable construction measures, third world cities transform into vulnerable centers.density in metropolitan such as Isfahan ,beside growing population ,without caring to economic, social, spatial ,aesthetic and the other urban planning effects ,has created many conflicts so has drown the urban planners attentions. Â Â Â Â 2- Methodology Â This research has aimed to achieve a logic urban density model (land use, high and population density) and survey the effect of it on the Isfahan vulnerability of earthquake using fuzzy approach .This research is based on the density model based on the fuzzy logic and documentary in the way of data collecting Â For mapping, measuring, and modeling the urban density in connection with active faults, various data on geology, seismology and demography of study were collected. These data was in form of map and census data. The study area is Isfahan city is located about 340 km south of Tehran and is the capital of Isfahan Province and Iran 's third largest city (after Tehran and Mashhad ). Isfahan city has a population of 1695789 and the Isfahan metropolitan area had a population of 3,430,353 in the 2006 Census, the third most populous metropolitan area in Iran after Tehran and Mashhad. Â Â 3- Discussion Â Various disasters like earthquake are natural hazard that kill thousands of people and destroy billions of dollars of habitat and property each year. The rapid growth of the urban density and its increased concentration often in hazardous environment has escalated both the frequency and severity of natural disasters. Â In research about earthquake hazard, Isfahan city is at high risk earthquake hazard. In this research, analysis relationship between urban density and earthquake vulnerability and the effects of urban centralization on earthquake vulnerability in Isfahan cities, was studied. With regard to historical earthquake, earthquake seismicity background and varieties faults, Isfahan cities are at high risk of earthquake hazard. Â The seismic vulnerability of a region is determined by several factors. One of them is the level of seismic hazard, determined usually by identification of either active faults or seismic zone source, zones based on the historical location of earthquake epicenters .recent neotectonic studies consider that Isfahan had been developed on and close to six active fault basins. Isfahan's location between six active faults means it is subject to natural hazards like earthquake shaking, earthquake fault rupture and land deformation. As these active faults start to move, Isfahan will continue to be subject to earthquake-related hazards.In this research, analysis relationship between urban dencity and earthquake vulnerability, and use of documentary data. The effects of urban centralization on earthquake vulnerability in Hormozgan cities, was studied. Â Â 4- Conclusion Â The results have showed that, in the survey of urban density, the relation between land use, high and population density should be considered also fuzzy approach in data normalization is one of the best approaches for solving this problem. The greatest coefficients of Vulnerability are land use, and population density. Â In this way, without caring to the density distribution, urban compacting in the specific region and so citizen tendency for specific residency of the same region will increase the vulnerability of earthquake. Zone 3 and 6 in Isfahan city has the highest meaning ranking of are vulnerability than other zone .On the other hand these zones has the greatest amount of all land use, high and population density. So satiation of these zones in recent years and the historical texture of them need the changing of policy density more than before. Â Key words: high density, population density, land use density, urban Vulnerability Fuzzy logic, Isfahan City. Â Â Reference Â Ahmady , Hasan and Mohamadreza ShikhKazem, (2006). "The role of planning for construction density in earthquake vulnerability decrease", the 2th international conference in crisis management and disaster. Â Akbari , nematolah and Mahdi Zahedikwyvan, (2008). The use of ranking methods and indicators decision making, dehyariha and shardariha publication, 1th publich, Tehran. Â Ambraseys, N.N.and Melville,C.P. (1982).A history of Persian earthquake, Cambridge earth science series . Â Aryafar , Alireza (2002). 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