نوع مقاله : مقاله علمی پژوهشی

نویسندگان

• رسول صمدزاده ¹
• احمد خواجوی ²
• محمدتقی معصومی ³

¹ گروه جغرافیا دانشگاه آزاد اسلامی واحد اردبیل، اردبیل، ایران

² گروه جغرافیا، واحد اردبیل، دانشگاه آزاد اسلامی، اردبیل، ایران

³ گروه جغرافیا، واحد اردبیل، دانشگاه آزاد اسلامی، اردبیل، ایران.

چکیده

زمین‌لرزه‌ها عامل ویرانی بسیاری از سکونتگاه‌های انسانی مخصوصاٌ بافت‌های فرسوده و قدیمی در طول تاریخ بشر بوده-اند. این قبیل بناها به ویژه در برابر مخاطرات لرزه‌ای آسیب‌پذیر هستند. نخستین گام برای کاهش خطر زمین‌لرزه شامل درک خطر لرزه‌ای موجود و ارزیابی راهبردهای احتمالی برای کاهش آن است. در این پژوهش از یک روش مبتنی بر نمایۀ آسیب‌پذیری برای ارزیابی خسارت مورد انتظار در بافت‌های فرسودۀ شهر اردبیل استفاده شده است. واکاوی خطرپذیری برای سناریوهای زمین‌لرزه تعریف شده توسط شدت‌های مهلرزه‌ایV ، V-VI ، VI ، VI-VII و VII برای طراحی برنامه‌های اضطراری لرزه‌ای انجام شده است. اوج شتاب اولیه زمین برای یک دوره بازگشت 475 ساله 0.04g است که مربوط به شدت VII می‌باشد. بنابراین، ضمن کمی‌سازی آسیب فیزیکی، تأثیر آن بر جمعیت و سایر مقادیر مانند آوار و هزینه اقتصادی بررسی شده است. علی‌رغم خطر لرزه‌ای متوسط تا زیاد در اردبیل، نتایج نشان می‌دهد که به دلیل قدمت زیاد، گونه‌شناسی بنایی تقویت نشده (یا غیر مسلح) و تقویت شده (مسلح) ساختمان‌های واقع در بافت‌های فرسوده و آسیب‌پذیری محیط ساخته شده، خطر بسیار زیاد است و آسیب‌پذیرترین بافت‌ها در مناطق یک و دو شهری واقع گردیده-اند.

کلیدواژه‌ها

• آسیب‌پذیری فیزیکی
• سناریوهای لرزه‌ای
• خطرپذیری لرزه‌ای
• بافت‌ فرسوده
• اردبیل

موضوعات

• سایر زمینه هایی مطالعاتی جغرافیایی و بین رشته ای

عنوان مقاله [English]

Assessment of physical vulnerability of decayed textures Ardabil Urban against seismic risk

نویسندگان [English]

• rasoul samadzadeh ¹
• Ahmad Khajavy ²
• mohamad taghi masoomi ³

¹ Department of Geography, Islamic Azad University Ardabil Branch, Ardabil, Iran

² PhD Student Department of Geography and urban planning, Ardabil Branch, Islamic Azad University, Ardabil, Iran

³ Department of Geography, Ardabil Branch, Islamic Azad University, Ardabil, Iran

چکیده [English]

Introduction
Over the last few decades, natural disasters and their aftermath have become a major concern for leaders and organizations around the world. Vulnerability is the "characteristics of an individual, group or system and their situation that affect their ability to anticipate, cope with, resist and recover from natural hazards." Physical vulnerability is: "The probability (or potential) of being affected or damaged by a specific physical component or element under the influence of a particular external driving force, for example a natural hazard such as an earthquake. Today, physical vulnerability is a component. The main key elements are used as model input data by organizations in charge of risk prevention and mitigation, and the development of building codes and guidelines. A look at the seismic history of Iranian cities in less than a hundred years, the widespread vulnerability of Iranian cities to this natural disaster is evident, of course, among the concerns of residents of dilapidated cities. It will be far more than others. The main goal of the action plan is to provide a rapid and effective response that minimizes potential damage to people, property and the environment, and returns basic services to people in the shortest possible time.
 
Data and Method
In this study, a method based on the vulnerability index has been used to assess the expected damage in Ardabil. Risk analysis for seismic scenarios defined by seismic intensities V, V-VI, VI, VI-VII and VII has been performed to design seismic emergency plans. This method uses the mean of quasi-experimental vulnerability functions, which for a given vulnerability index is strongly related to the seismicity and the expected damage. According to the country's seismic Codes, the basic peak ground acceleration for a 475-year return period is 0.04g, which corresponds to an intensity of VII. Thus, while quantifying physical damage, its impact on the population and other amounts such as debris and economic costs have been investigated.
 
Results and Discussion
Vulnerability of buildings in Ardabil shows an average value of 0.59 for concrete buildings and 0.93 for buildings with building materials, which are the most vulnerable. Therefore, it is predicted that buildings with building materials that belong to worn-out structures will have a higher degree of damage. The distribution of highly vulnerable neighborhoods is seen in the central core of the city. The vulnerability index of areas 1 and 3 is higher than other areas. For the seismic scenario VII, the degree of vulnerability of these textures is heavy, very heavy and completely devastated. In the worst-case scenario, about three in a thousand people die of decayed textures, and not every thousand people suffer various injuries. An earthquake with a intensity of V-VI will cost approximately 98 million Rials and a intensity VII equal to 6800 million Rials for these textures. Due to the impact of a seismic crisis on narrow and uneven communication passages and arteries, there is a significant volume of expected debris production among the eroded neighborhoods (for scenarios V-VI and VII, respectively, between 1701 up to 13989 tons). Due to the combined effects of the large volume of debris produced and the urban pattern of narrow and irregular passages, any movement will face several problems. In the seismic scenario with intensity V-VI, 332 people from the population of     decayed textures and in the scenario with intensity VII, 3224 people from the population of textures these become homeless. Therefore, the only way to reduce seismic risk with a vulnerability reduction approach is to apply seismic instructions and increase public awareness of these issues.
 
Conclusion
The city of Ardabil is in the range of moderate to high seismic hazard, which is mainly due to the large accumulation of population and old and vulnerable buildings. Vulnerability of residential buildings is high, mainly due to their age and lack of knowledge and awareness of seismic hazard and in terms of seismic actions expected in the design and construction of buildings. This high vulnerability causes significant direct physical damage to buildings, especially worn-out structures, even for low-intensity earthquakes. As a result, the expected physical damage in the case of moderate earthquakes is significant. For a intensity V earthquake, the damage is not expected to be significant, but for a intensity VII scenario, all five areas and the dilapidated tissues within them will experience a level of damage that is slightly higher. Damage is 2 (moderate). In addition to the significant number of casualties, emergency management after the earthquake and subsequent recovery of normal city activities in the medium and long term is important.

کلیدواژه‌ها [English]

• physical vulnerability
• seismic risk
• urban renewal
• decayed textures
• Ardabil