ارزیابی میزان آسیب‌پذیری بافت‌های شهری در برابر زلزله مطالعه موردی شهر کرمانشاه

آسیبها و خسارات ناشی از حوادث و مخاطرات طبیعی در دهه‌ای اخیر، مخصوصاً در آفریقا، آمریکای لاتین و به ویژه آسیا که از لحاظ اقتصادی در وضعیت ضعیفتری به سر می برند رو به افزایش است. تعدد و تنوع حوادث طبیعی در جهان ضرورت و اهمیت توجه به مدیریتی کارآمد و موثر در برنامه ریزی برای بالا بردن تاب آوری شهری در مقابل شوکه‌ای حاصل از حوادث و سوانح طبیعی یا انسان ساخترا روشن می سازد. ایران به علت موقعیت جغرافیای و قرارگیری روی کمربند لرزه خیز آلپ، هیمالیا، همواره در معرض زمین لرزه هایی با شدت بالا قرار دارد. استان کرمانشاه نیز با توجه به قرارگیری در مجاورت گسل اصلی زاگرس و گسله‌ای فرعی نهاوند، قارون، صحنه و مروارید در معرض خطر وقوع زلزله قرار دارد و زلزله‌های با قدرت بیش از 6 و 7 ریشتر در ساله‌ای 1336 و 1396 گواه این ادعا است. اینپژوهش ضمن شناخت و بررسی مبانی نظری و مفاهیم مرتبط با زلزله، به بررسی میزان آسیب پذیری کالبدی شهر کرمانشاه در صورت رخداد زلزله پرداخته که با عنایت به اهمیت عوامل و معیاره‌ای کالبدی موثر بر آسیب پذیری در اثر زلزله، متغیرهای مذکور بررسی گریده اند. با در نظر گرفتن شرایط و وضعیت کنونی شهر و همچنین بررسی و مداقه در پژوهشهای پیشین مرتبط با موضوع تحقیق، جهت تعیین عوامل موثر در آسیب پذیری کالبدی شهر کرمانشاه، 2معیار اصلی پایداری فیزیکی بافت و کاراییبافت در زمان بحران و همچنین 11 زیرمعیار )متغیر( مساحت زمین، سطح اشغال، تراکم جمعیت، تعداد طبقات، عرض معبر، قدمت ساخت، نوع سازه و مصالح، دسترسی به فضای باز شهری، دسترسی به مراکز امدادی، فاصله از مرکز خط رزا و نوع بافت شهری به عنوان پارامترهای موثر در آسیب پذیری کالبدی شهر کرمانشاه ناشی از زمین لرزه تعیین و به منظور امکان تعیین میزان آسیب پذیری هر معیار نیز از شاخصهای کمی وکیفی برگرفته از پژوهشهای قبلی و اخذ نظر کارشناسان استفاده گردیده است. باعنایت به مطالب ذکر شده مسئله اصلی این پژوهش شناسایی، بررسی، دسته بندیو مشخص نمودن میزان اثر هر یک از عوامل تاثیرگذار در آسیب پذیریکالبدی شهر ناشی از زلزله بوده و سعی کرده تا با استفاده از روشها و مدله‌ای علمی؛ ارزیابی، سنجش و تعیین اولویت بندی میزان آسیب پذیری کالبدی شهر کرمانشاه را بررسی نماید.

assessment of urban fabric vulnerability to earthquakes: a case study of kermanshah city

earthquakes are the most destructive and deadly natural disasters. kermanshah, as the largest metropolitan city in the central-western part of the country, has significant regional influence politically, socially, economically, and demographically. due to the city's poor urban structure, kermanshah is highly vulnerable to earthquakes, and the probability of emerging problems and critical situations is very high in the event of an earthquake. therefore, it is necessary to provide systematic and efficient methods for crisis management to reduce the level of vulnerability. this study aims to identify the factors affecting physical vulnerability and provide a method and model to assess the vulnerability of urban areas to help urban management reduce casualties and damages caused by earthquakes before, during, and after the crisis. the research is applied, and the method used is descriptive and analytical. the study uses the analytic hierarchy process (ahp) model in the arc gis software environment to measure and prioritize the vulnerability of different regions of kermanshah city. the results indicate that 31.69% of the city's buildings are located in very high and high vulnerability zones regarding physical sustainability, with region 3 being the most vulnerable area. in terms of crisis relief efficiency, 13.65% of the city's buildings are in very high and high vulnerability zones, with region 5 being the most vulnerable area. regarding physical vulnerability, 23.78% of the buildings are in very high vulnerability zones, and 34.97% are in high vulnerability zones. regions 3, 7, 4, and 2 are the most vulnerable areas in kermanshah in the event of an earthquake. keywords: vulnerability, earthquake, kermanshah, analytical hierarchy process, gis introductionthe variety and frequency of natural disasters worldwide emphasize the need for effective management in urban planning to enhance resilience against the shocks of natural or human-made disasters. iran, due to its geographical location and position on the alpine-himalayan seismic belt, is constantly exposed to high-magnitude earthquakes. kermanshah province, located near the main zagros fault and secondary faults such as nahavand, qarun, sahneh, and morvarid, is highly susceptible to earthquakes, with events exceeding magnitudes of 6 and 7 in 1957 and 2017 serving as evidence of this vulnerability. therefore, it is essential to provide systematic and efficient methods based on urban planning principles to manage crises and reduce kermanshah city's vulnerability to earthquakes.this study examines the theoretical foundations and concepts related to earthquakes, urban planning, and city resilience. it evaluates the physical vulnerability of kermanshah city in the event of an earthquake and identifies the factors, criteria, and variables affecting this vulnerability. ultimately, 11 sub-criteria and two main criteria are identified as effective factors contributing to the city's vulnerability. after analyzing and processing the data, vulnerability maps were created for all sub-criteria, and it was found that the highest vulnerability is related to the sub-criterion of open spaces, followed by the proximity to fire stations. the highest vulnerability in the main criteria is related to the efficiency of the urban fabric during a crisis. according to the results, more than half of the buildings in the city are located in very high and high vulnerability zones in the event of an earthquake. the main objective of this research is to identify, analyze, categorize, and determine the impact of each factor affecting the physical vulnerability of the city to earthquakes. the research aims to use scientific methods and models to assess, measure, determine, and prioritize the vulnerability of urban areas in kermanshah to potential earthquakes. research methodologythe required data were collected through library and documentary methods, using available information from the gis unit of kermanshah municipality, satellite images (landsat), and fieldwork. the aim of this study is to evaluate kermanshah city's vulnerability based on the city's physical criteria. to determine the factors and variables affecting vulnerability, the study considers the current conditions of the city, as well as relevant previous research. the two main criteria of physical sustainability of the urban fabric and the efficiency of the fabric during a crisis, along with 11 sub-criteria (variables) such as land area, building coverage ratio, population density, number of floors, street width, building age, construction type and materials, access to open urban spaces, access to emergency centers, distance from hazard zones, and urban fabric type, were identified as key factors affecting the physical vulnerability of kermanshah to earthquakes. after entering the spatial and descriptive data for each sub-criterion into gis software, the data were stored, processed, and analyzed. vulnerability maps for each sub-criterion were created, and in order to combine the layers (variables) and generate an overall vulnerability map, the importance and priority of each sub-criterion were determined. for this purpose, expert opinions were collected using questionnaires, and the analytic hierarchy process (ahp) was applied using expert choice software to calculate the final weights of the criteria and sub-criteria and ensure the consistency of judgments. the vulnerability of each sub-criterion was categorized into four zones: very high, high, medium, and low, based on the impact of each indicator.
map of the physical vulnerability of kermanshah city due to earthquake
table of physical vulnerability of kermanshah city due to earthquake (number of buildings and percentage)

	very high vulnerability	high vulnerability	medium vulnerability	low vulnerability	very high vulnerability	high vulnerability	medium vulnerability	low vulnerability
region one	1957	4516	4721	2704	1.175	2.711	2.834	1.623
region two	4529	6422	3986	3305	2.719	3.855	2.393	1.984
region three	14977	10545	3653	4737	8.991	6.331	2.193	2.844
region four	6724	3811	2748	1476	4.037	2.288	1.650	0.886
region five	2271	14638	7896	5850	1.363	8.788	4.740	3.512
region six	386	2205	6032	5313	0.232	1.324	3.621	3.190
region seven	7839	10382	6315	620	4.706	6.233	3.791	0.372
region eigh	935	4277	2950	7852	0.561	2.568	1.771	4.714
sum	39618	56796	38301	31857	23.784	34.097	22.994	19.125
max	14977	14638	7896	7852	8.991	8.788	4.740	4.714
the most vulnerable area	three	five	five	eigh	three	five	five	eigh

conclusionin the event of an earthquake in kermanshah city, the sub-criteria of access to open spaces and distance from fire stations will have the worst conditions. specifically, 71.53% of buildings (119,159 buildings) are in very high vulnerability zones regarding access to open spaces, and 65.76% (109,539 buildings) are in very high vulnerability zones regarding access to fire stations. in these two sub-criteria, the worst conditions are found in regions 3, 5, and 7, respectively. the sub-criteria of urban fabric type, access to healthcare centers, and building coverage ratio fall into the very high vulnerability zone, each with frequencies ranging from 35% to 43%, ranking second. the most vulnerable areas in these sub-criteria are regions 3, 7, and 2.in the physical sustainability criterion, 34.27% of the city's buildings are located in very high vulnerability zones, and 35.04% are in high vulnerability zones, which is a significant and concerning number. in this criterion, the most vulnerable regions are regions 3, 4, and 2. in terms of the efficiency of the urban fabric during a crisis, 33.08% of the city's buildings are in very high vulnerability zones, and 31.93% are in high vulnerability zones. the worst conditions in this criterion are found in regions 5, 7, and 3.regarding the overall physical vulnerability of the city to potential earthquakes, 39,618 buildings are in the very high vulnerability zone, and 56,796 buildings are in the high vulnerability zone. this means that 96,414 out of 166,500 buildings in the city (57.81%) are located in very high and high vulnerability zones. the final results of this study reveal the harsh reality that, in the event of an earthquake, unfortunately, more than half of kermanshah city will be in very high and high vulnerability zones. if proper planning, scientific policy-making, and timely implementation of operational programs are not carried out, the casualties and damage resulting from the earthquake will be catastrophic and irreparable. referencesahadinezad, m. (2013). evaluation of internal factors affecting the vulnerability of city buildings to earthquakes using gis. journal of environmental planning, 6(20), 23-52.pourmohammadi, a., et al. (2013). development of an analytical framework based on gis for assessing urban durability against earthquakes: a case study of tehran. quarterly journal of disaster risk reduction, 8, 91-105.iranian red crescent society, youth organization (2003). safety tips before, during, and after floods. golestan a, 2nd edition.habibi, e. (2010). reducing earthquake vulnerability in tehran city using ahp and gis. ph.d. thesis, university of tehran, tehran, iran.shamai, m., et al. (2017). analysis of architectural sustainability vulnerability in kashan city to earthquakes using fuzzy ahp and expert choice. iranian geomatics, 6(3), 143-155.khalilabad kalantari, h., et al. (2012). investigating the role of social capital in reducing earthquake risk in the historical fabric of yazd (case study: fahadan neighborhood). journal of studies on iranian islamic cities, 3(9).hosseindokht, m. (2010). identification and prioritization of earthquake vulnerability using ahp and gis (case study: kermanshah city). journal of geographic information science, 20(80), 67-79. isdr, 2004: living with risk: a global review of disaster reduction initiatives united nations international strategy for disaster reductionishita, k. (2010). application of hierarchical analysis method and gis in earthquake vulnerability estimation. international journal of earth sciences and engineering, 3(2), 231-238.rashed.t,weeks.j, 2004: exploring the spatial association between measures from satellite imagery and patterns of urban vulnerability to earthquake -- hazards,international population center, department of geography,san diego state university, san