ارزیابی تاب آوری شهری در مقابل زلزله (مطالعه موردی: اسلام آباد غرب) (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
یکی از شناخته شده ترین و مخرب ترین سوانح طبیعی در دنیا و به خصوص در کشور ایران، زلزله می باشد. بر همین اساس مسئله ارزیابی تاب آوری شهری در مقابل خطر زلزله که در مطالعات شهری و شهرسازی یک مفهوم نسبتا جدید است، بسیار حائز اهمیت می باشد. طی دو دهه اخیر جهت ارزیابی تاب آوری شهری در مقابل خطر زلزله، روش های متعدد تصمیم گیری چندمعیاره (MCDM) مبتنی بر سیستم اطلاعات جغرافیایی (GIS) توسعه یافته است. همچنین در سال های اخیر، تئوری منطق فازی در مطالعات مربوط به مخاطرات طبیعی مانند زلزله، کارایی زیادی داشته و به کمک آن می توان عدم قطعیت موجود در تشخیص الگوها را مدل سازی نمود و تا حد ممکن به شیوه تشخیص انسانی نزدیک شد.بر همین اساس مسئله ارزیابی تاب آوری شهری در مقابل خطر زلزله بسیار حائز اهمیت می باشد. در این پژوهش که با هدف ارزیابی تاب آوری شهر اسلام آبادغرب در مقابل خطر زلزله انجام شده، از دو مدل تلفیقی ترکیب خطی وزنی (WLC) و عملگر فازی گاما (Gamma) استفاده شد. همچنین جهت وزن دهی متغیرها از روش تحلیل سلسله مراتبی (AHP) استفاده شده است. جهت ارزیابی تاب آوری شهر اسلام آبادغرب در مقابل زلزله با استفاده از دو مدل تلفیقی ترکیب خطی وزنی و عملگر گاما با مقادیر 3/0، 5/0 و 9/0، نقشه هایی در پنج کلاس با میزان تاب آوری خیلی کم، کم، متوسط، زیاد و خیلی زیاد تهیه شد. از طرفی جهت ارزیابی دقت و صحت نقشه های ایجاد شده توسط مدل های مذکور از نتایج شاخص مجموع کیفیت (QS) استفاده شد. نتایج محاسبات ارزیابی دقت نشان داد که، مقدار شاخص مجموع کیفیت (QS) نقشه های تولید شده توسط عمگلرهای گامای 3/0، 5/0، 9/0 و مدل WLC به ترتیب 051/0، 052/0، 138/0 و 611/0 می باشد. با توجه به بیشتر بودن مقدار QS مدل WLC نسبت به مقدار QS عملگرهای گامای 3/0، 5/0 و 9/0، نتیجه گیری می شود که کارآمدترین و دقیق ترین مدل برای ارزیابی تاب آوری شهر اسلام آبادغرب در مقابل زلزله، مدل WLC می باشد. همچنین نقشه پهنه بندی تاب آوری تولید شده توسط مدل WLC نشان داد که نواحی غربی و جنوبی شهر اسلام آبادغرب از بیشترین میزان تاب آوری در مقابل زلزله برخوردار است و کمترین میزان تاب آوری مربوط به نواحی شرقی و شمال شرقی شهر می باشد.Evaluating Urban Resilience against Earthquakes (Case Study: Islamabad Gharb)
Introduction
Earthquake should be considered as one of the most prevalent and destructive natural disasters that all the countries of the world, especially Iran, face with. Therefore, it is important to evaluate urban resilience against earthquakes. Urban resilience is a new and under researched concept in urban studies and urban planning. Accordingly, it is necessary to evaluate the resilience of the city of Islamabad Gharb, like any other city, against earthquakes. It seems that considering and resorting to some sources we can understand the vulnerability of Iranian cities. It is necessary to use a suitable model and various types of spatial and non-spatial data. Moreover, the analyses related to the geographic information system and most importantly, the review and analysis of the current global experiences should be considered. Taking these issues into account, we can achieve the risk map of Iranian cities against earthquakes. Additionally, by making the necessary preparations, this phenomenon can be turned into a planned process in crisis management caused by natural hazards. The purpose of this research was to evaluate the resilience of the city of Islamabad Gharb against the risk of earthquakes. For this purpose, the integrated model of Weighted Linear Combination (WLC) and fuzzy Gamma operator (Gamma) were used. Analytical Hierarchy Method (AHP) was applied for weighting the variables. The final goal was to see the status of urban resilience against earthquakes in Islamabad Gharb.
Method
This applied research used a descriptive-analytical method. For this study many resources were used including documentary and library studies, information about and provided by the municipality of Islamabad Gharb city, and other reports including studies that were previously conducted in this field on the city. Moreover, the studies and plans that have been carried out by the deputy of planning of the governorate should be added to the sources. Two integrated models of Weighted Linear Combination (WLC) and fuzzy Gamma operator (Gamma) were used to evaluate the resilience of the city of Islamabad Gharb against earthquakes. Analytical Hierarchy Method (AHP) was also used to weight the variables. For evaluating the resilience of the city against the earthquake, two integrated models of WLC and gamma with values of 0.3, 0.5 and 0.9 were used and the final maps on five classes (very low, low, medium, high, and very high level of resilience) were prepared. Moreover, for evaluating the accurancy and correctness of the final maps produced by the two models, the results of total quality index (QS) were used.
Results
Total quality index (QS) was applied for ensuring the accuracy of WLC models and fuzzy gamma operators of 0.3, 0.5 and 0.9 to prepare earthquake resilience zoning map. Higher QS of zoning model or method indicates that the calculations and predictions for resilience zoning map are highly accurate. By using the QS we can measure the accuracy of the calculations related to the WLC model and fuzzy gamma operators. Moreover, the QS value of each resilience class related to each of the mentioned models can be obtained separately. In addition to these two cases, it is possible to compare the accuracy and correctness of calculations related to each resilience class with the accuracy and correctness of calculations of other resilience classes. The QS values for very low, low, medium, high and very high resilience classes related to the zoning map created by WLC model, respectively, were 0.007, 0.293, 0.001, 0.247 and 0.063. The QS value of "low" resilience class (0.293) is higher than the QS value of other resilience classes. This can be interpreted that the calculations related to the area of the low resilience class have been done with more precision and accuracy than other resilience classes. The following classes are high, very high, very low and medium resilience classes. Moreover, the QS for the WLC model is the algebraic sum of the QS values for very low, low, medium, high and very high resilience classes. Taking into account the QS, the accuracy and correctness of the WLC model for the preparation of resilience zoning map against earthquake risk for the city of Islamabad Gharb was 0.611.
Discussion and Conclusion
The QS index can be used to calculate the accuracy of the performed calculations related to the WLC model and fuzzy gamma operators. It is also possible to obtain the QS value of each resilience class related to each of these two models separately. Moreover, the precision and accuracy of calculations of each resilience class can be compared with the precision and accuracy of calculations of other resilience classes. QS value for the very low, low, medium, high, and very high resilience classes pertaining to the zoning map created by WLC model were, respectively, 0.007, 0.293, 0.001, 0.247, and 0.063. The QS value of low resilience class (0.293) is higher than the QS value of other resilience classes. We may interpret it that the calculations pertaining to the low resilience class have been done with more precision and accuracy than the calculation of other resilience classes. Other classes are, respectively, high, very high, very low, and medium resilience classes. Moreover, the QS for the WLC model is the algebraic sum of QS values for the very low, low, medium, high, and very high resilience classes. Taking the QS, the precision and accuracy of the WLC model in preparing the zoning map of resilience against earthquake risk for Islamabad Gharb city is 0.611.
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