بررسی و ارزیابی تاب آوری کالبدی فضاهای شهری در برابر زلزله (مطالعه موردی: شهر مشهد) (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
زلزله همواره جزء مهم ترین مخاطرات طبیعی هستند که هرساله تعداد زیادی از مردم جهان گرفتار آثار نامطلوب آن می شوند، بنابراین تاب آوری وضع موجود نقش حیاتی در کاهش آسیب پذیری شهرها و تقویت توانایی های شهروندان برای مقابله با خطرات ناشی از زلزله دارد . در این راستا هدف پژوهش حاضر بررسی و ارزیابی تاب آوری کالبدی فضاهای شهری در برابر زلزله (مطالعه موردی: شهر مشهد)، می باشد. این تحقیق به لحاظ هدف کاربردی و از نظر روش توصیفی- تحلیلی می باشد. گردآوری داده ها، از طریق مطالعات کتابخانه ای (اسنادی) و جمع آوری اطلاعات آماری که شامل اسناد و مدارک، مشاهده و مستندسازی می باشد، صورت می پذیرد. اطلاعاتی که در این پژوهش مورد نیاز است بوسیله ی روش کتابخانه ای گردآوری شده است. عمده اطلاعات مربوط به شاخص های این تحقیق از طریق مراجعه به اداره آمار و تحلیل اطلاعات معاونت توسعه و برنامه ریزی سرمایه انسانی شهرداری مشهد، استفاده از آمارنامه شهر مشهد در سال 1402 به دست آمده است. جامعه آماری پژوهش حاضر کارشناسان و نخبگان شهر مشهد می باشد که به روش هدفمند، 20 نفر انتخاب شدند. جهت تجزیه و تحلیل داده ها از نرم افزار Arc GIS و مدل تحلیل سلسله مراتبی ( AHP ) و روش ترکیب خطی وزنی ( WLC ) و استفاده شد. خروجی نهایی آسیب پذیری شهر مشهد در برابر زلزله را نشان که 1147 هکتار (3.55 درصد) در وضعیت کاملاً نامناسب و فقط 2155 هکتار (6.66) درصد در وضعیت کاملاً مناسب قرار دارند. طبق نتایج از میان مناطق هفده گانه شهر مشهد مناطق 7 و 9، بیشترین میزان آسیب پذیری را دارند.Investigating and evaluating the physical resilience of urban spaces against earthquakes (Case study: Mashhad city)
Introduction One of the most fundamental and threatening hazards is earthquakes. The risk of earthquakes is one of the most significant dangers that constantly threaten cities. Therefore, understanding the current state of resilience plays a vital role in reducing urban vulnerability and enhancing citizens' ability to cope with the risks posed by natural disasters. This is because earthquakes occur suddenly and can have widespread impacts across a region, even affecting national issues. The most critical factors leading to a crisis during an earthquake are the physical vulnerabilities of the city. Among these, Mashhad in Razavi Khorasan is one of the major and important cities in Iran, located in a very high-risk zone. Its proximity to 55 active and seismic faults, along with a population of over 3,057,679, and the presence of vast human, cultural, and religious assets, have positioned Mashhad as a highly significant city in terms of seismic risk. The Razavi Khorasan region, structurally, lies within the tectonic zones of Kopet Dag, Binalud, and Sabzevar (subzones of Central Iran). In all three zones, there are highly active and dynamic faults. Movements along these faults can lead to severe earthquakes with substantial damage. Additionally, for the religious metropolis of Mashhad, with its large population and vast area, factors such as unprincipled excavations, lack of attention to building safety, the presence of deteriorated structures in most parts of the city, poor-quality construction materials, inadequate design and construction of buildings and vital infrastructure relative to potential seismic intensity, lack of operational plans and capabilities for disaster management during response and recovery phases, and numerous vulnerable and deteriorated areas have made resilience, particularly in terms of physical aspects, a critical issue. Over the past two decades, various multi-criteria decision-making (MCDM) methods based on Geographic Information Systems (GIS) have been developed to assess urban resilience against earthquake risks. Therefore, research on the physical resilience of urban spaces in Mashhad against earthquakes using these methods and approaches is essential. The results can be used in formulating laws and regulations related to natural disaster management, vulnerability reduction, risk mitigation policies, and enhancing resilience, as well as in decision-making, planning, and policy-making by officials in Mashhad regarding natural disaster management. Methodology This research is applied in terms of purpose and descriptive-analytical in terms of method. Data collection is done through library studies (documents) and statistical information collection which includes documents, observation and documentation. The information required in this research is collected through library method. Most of the information related to the indicators of this research was obtained by referring to the Statistics and Information Analysis Department of the Human Capital Development and Planning Deputy of Mashhad Municipality, using the Mashhad City Statistics in 2023. The statistical population of the present study is experts and elites of Mashhad city; 20 people were selected through a purposeful method. Arc GIS software, Analytical Hierarchy Process (AHP) model, and Weighted Linear Combination (WLC) method were used to analyze the data Results The final output of Mashhad city's vulnerability to earthquakes shows that 1147 hectares (3.55%) are in a completely unsuitable condition and only 2155 hectares (6.66%) are in a completely suitable condition. According to the results, among the seventeen districts of Mashhad city, districts 7 and 9 have the highest level of vulnerability. Discussion In this study, indicators such as the ratio of building height to street width, access to open spaces, access to service centers (fire stations, etc.), population density, distance from healthcare facilities, distance from faults, distance from gas stations and fuel depots, building age, location in dead-end alleys, type of facade materials, and access to main city roads were examined. These indicators are determining factors that reflect the level of vulnerability in different urban areas. By using this set of factors and defining their boundaries, vulnerable areas of the city were identified. The results showed that 1,147 hectares (3.55%) are in a completely unsuitable condition, 7,964 hectares (24.64%) are in an unsuitable condition, 15,254 hectares (47.21%) are in a moderate condition, 5,789 hectares (17.91%) are in a suitable condition, and only 2,155 hectares (6.66%) are in a completely suitable condition. According to the results, among the seventeen districts of Mashhad, districts 7 and 9 have the highest vulnerability, while districts 4 and 16 have the lowest vulnerability. Conclusion The overall results indicate that Mashhad, like many other cities, is located on several active faults, making it a sensitive and high-risk area for earthquake hazards. Sooner or later, the city will face such a challenge. Therefore, reducing damage, managing crises, and ultimately enhancing the resilience of cities against hazards such as earthquakes is essential and necessary. Acknowledgments This research did not receive any specific grant . From funding agencies in the public, commercial, or not-for-profit sectors.
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