ارزيابي آسيب‌پذيري شهري در برابر زلزله با تاكيد بر مديريت بحران شهري در شهر كاشمر

Assessment of Urban Vulnerability to Earthquake with Emphasis on Urban Crisis Management in the City of Kashmar

قبل از وقوع بلايايي طبيعي، به ويژه زلزله در مناطق شهري، مديريت بحران هاي پديد آمده يكي از ضرورت هاي نظام برنامه ريزي شهري است. از اين رو، تعيين ميزان آسيب پذيري فيزيكي در برابر زلزله اهميت بالايي دارد. همچنين، طبقه بندي واحد هاي مكاني شهري از نظر درجه ي آسيب پذيري در برابر زلزله و پهنه بندي اراضي شهري براي شناسايي نواحي در معرض خطر امري ضروري است. با توجه به اين كه ايران از نظر وقوع بلايايي طبيعي جزو ده كشور جهان است و شهر كاشمر در منطقه اي زلزله خيز واقع شده است، ضرورت اين كار بيشتر به چشم مي آيد. در اين پژوهش، نواحي شهري كاشمر از نظر آسيب پذيري كالبدي با استفاده از مدل VIKOR اولويت بندي شدند تا نواحي اين شهر قبل از وقوع زلزله براي كاهش آسيب هاي ناشي از زلزله بهسازي و آماده سازي شوند. يكي از مراحل مدل VIKOR وزن دهي به معيارهاي دخيل در امر اولويت بندي است كه در اين پژوهش براي وزن دهي به معيارها از مدل AHP استفاده شد. گفتني است كه روش پژوهش مقاله حاضر توصيفي تحليلي است. نتايج پژوهش حاضر نشان مي دهد ناحيه ي 8 كمترين آسيب پذيري و ناحيه ي 3 شهر كاشمر بيشترين آسيب پذيري كالبدي در برابر زلزله را دارد. همچنين، در ادامه ي پژوهش، با استفاده از مدل اسپيرمن ميزان همبستگي بين تراكم جمعيت و ميزان آسيب پذيري در نواحي شهري كاشمر ارزيابي شد. ميزان همبستگي 0.5866 نشان مي دهد كه همبستگي بالايي بين اين دو متغير وجود دارد و تراكم بالا سبب افزايش ميزان آسيب پذيري در نواحي شهر كاشمر مي شود.

In advance crisis management of natural disasters, particularly earthquakes in urban areas is one of the necessities of urban planning. However, nowadays with the help of technology we can determine the risk of crisis in the urban areas and settlements. Due to population growth and increasing urbanization, the occurrence of natural disasters such as earthquake can cause terrible disasters in the cities. The need to reduce the vulnerability of the cities is one of the main objectives of physical planning of urban areas and city designing. The city of Kashmar in one of Irans earthquakeprone areas (due to its adjacency to the Lut fault) has witnessed the sever destruction from the September 25, 1903 earthquake (with a magnitude MS= 5/9) and Torbat Haidariye earthquake on 25 May 1923 (a magnitude MS= 5/8). It is very important to identifying vulnerable areas to earthquakes in advance. Accordingly the objective of this study is to identify the vulnerability of urban areas of Kashmar city to the earthquake by using VIKOR model of urban planning. The vulnerability of the city was computed on several parameters among which the population density is the most important one. In order to carry out the research eleven population and other indices were used. These indices are as follows: Building Materials The quality of the building Old buildings Number of floors The materials of facades of building Compatibility of land uses Access to network passages Distance from the main fault The building density Numbers of population and Relief and rescue centers. By using the VIKOR ranking model the vulnerability of the urban areas of the city was identified and classified. The correlation between the city vulnerability and each of these indices was calculated. The impact of the indices on the city vulnerability was calculated according to the AHP model. The results of the study showed that the zone 3 had the highest and the zone 8 had the lowest physical vulnerability in the model. Based on the results of the Spearman correlation, the impact of the population on the vulnerability was about .5866 which is relatively noteworthy. This means that highest degree of vulnerability can occur in very populated areas of the city. All of the city was regionalized according to the degree of vulnerability to earthquake. The lack of amenities and facilities such as health centers, fire stations, building materials and weak areas within the city will increase the losses and casualties. It is noteworthy that comprehensive city planning in the future must improve and the needed facilities should be provided. In addition providing services to the residents, especially in critical times after the earthquake should be provided.