پديد آورندگان :
قهرودي تالي، منيژه نويسنده دانشيار گروه جغرافياي طبيعي، دانشكدهي علوم زمين، دانشگاه شهيد بهشتي , , پورموسوي ، سيدموسي نويسنده استاديار گروه جغرافيا، دانشگاه امام حسين (ع) , , خسروي ، سميه نويسنده ,
كليدواژه :
لرزهخيزي , مدل تاپسيس , روش تصميم‌گيري چند شاخصه , منطقهي يك تهران
چكيده فارسي :
شهرهاي ايران داراي شواهد متعددي از لرزهخيزي، همچون گسلهها و شكستگيها، بهويژه در زمينهاي آبرفتي است كه با ايجاد سازههاي سنگين شهري، ناپايداري بسترهاي شهري را بهارمغان آورده است. اين پژوهش با هدف تحليل پراكنش تخريب ناشي از لرزهخيزي در محيط شهري انجام شده است. منطقهي يك تهران از اين نظر انتخاب شده است كه در ناحيهي البرز مركزي، بر نهشتههاي كواترنري واقع شده است و داراي شواهد متعدد تكتونيكي، ازجمله وجود سازند هزار دره، وقوع زمينلرزههايي با بزرگي بيش از 7 ريشتر، چين خوردگي و گسلش در سازند هزاردره و وجود زمين لغزشهاي دامنهاي هستند. در اين مطالعه بهمنظور بررسي پتانسيل تخريب ناشي از زمينلرزه در منطقهي يك تهران، از نقشهي توپوگرافي، پراكندگي گسلهها، كاربري تهيهشده از سوي شهرداري، تراكم جمعيت، دادههاي ارتفاعي (DEM) استفاده شده است. بر اساس دادههاي فوق با توجه به شرايط تكتونيكي منطقهي يك تهران، معيارهاي ضريب خميدگي، نوع آبرفت، ارتفاع زمين، تغييرات ارتفاعي، تراكم شبكهي زهكشي، تراكم نسبي گسل، تراكم نسبي جمعيت و درصد فضاي باز، شاخصهاي انتخابشدهاي است كه ميتواند بيانگر تخريب ناشي از لرزهخيزي در اين منطقه باشد. پراكنش شاخصهاي مورد نظر با استفاده مدل تاپسيس از روشهاي تصميم‌گيري چند شاخصه مورد تحليل قرار گرفته است. نتايج مطالعات نشان داد كه حداكثر پتانسيل لرزهخيزي در بخش شمالي منطقهي يك، بهدليل بيشترين برونزدگيهاي آبرفتهاي قديميتر روي آبرفتهاي جديدتر، حضور گسلهاي اصلي و لرزهزا، حداكثر ضريب خميدگي و حضور شبكههاي آبرفتي اصلي قرار گرفته است.
چكيده لاتين :
Extended Abstract
Introduction
Cities in Iran are included numerous evidences with seismicity such as faults and fractures, particularly in alluvial land with heavy structures, have brought instability to the urban context. This research has been done to analyze of special distribution of seismicity damage in urban environment. District 1 of Tehran is selected from this point in that it is located in the geological Central Alborz, on the deposit of Quaternary and Karag formations and including evidences of neotectonic, such as present of Hezardareh formation, an earthquake with a magnitude of more than 7, folds and faulting in the Hezardareh formation, there are tectonics deposits and landslides.
Methodology
Data are used in this study include topographic maps, map of fault, landuse, population density and elevation Data. Based on the data and Tectonic Conditions, Curvature coefficient criteria, type of alluvium, elevation, and drainage network density, relative density of the fault, the relative population density and percentage of open space were selected as new criteria that could indicate Potential seismicity damage in this region. TOPSIS model of Multi Attribute Decision Making (MADM) method was used to evaluate the spatial of criteria. Topsis models are compensatory. Compensation to the notion that the exchange rate index is possible based on the severity of effects. In this method M choices by N method are evaluated and any problems can be considered as a geometric system of M points in an N-dimensional space.
Results and Discussion
Due to Situation of Tehran, effects of tectonic activities are very important for instability structures. The compositions of natural and human criteria were used to determine of seismic indicator. Curvature coefficient in district 1 of Tehran was selected because of related to tectonic fractions and the evidence reveals in Elahiyeh and Zaferanieh quarters. Also the main faults are active because of their replacement. The Faults within the study area are drawn from East to West and most of its distribution in is the West. The evidence has been observed at Tochal and Velenjak wich the range of elevation indicator in the most value. There are five main rivers and three temporary rivers in this area. The most of drainage density in the west of basin and belong to Darakeh,Velenjak and Darband rivers. The least of drainage density in the east of basin and consist to Jamshidieh and Maghsoudbaik rivers. There is not any drainage network in the center of basin. Density and human population growth as an indicator because increasing population density to increase their construction and operation of unauthorized building in frontage of urban areas. According to 2007 census, populations of about 370,000 were in the study area. Average annual growth of population from 1997 to 2007 was about 2.3 percent over the year. An outdoor space Index represents the area of the wasteland and urban green spaces. This indicator is a small amount of space occupied which increases stress.
Conclusion
The results showed that the maximum potential of sesmicty is located in the northern part of zone 1 because of the highest outcrops of older alluvial on newer alluvium, the main Seismicity fault, the maximum coefficient of curvature, and the main drainage networks such as Darabad, Jamshidieh, Darband and Golab Dareh. Kashank, Jamaran, Manzaryeh and Hesarak areas are located in this zone. High intensity zone includes the eastern region (region Sohanak). Curvature coefficient is maximum changes in this area. The fault Lavizan is affected this area and has created the hills. The alluvium has homogeneous and is formed layered regular Conglomerate, composed of rubble, sand and gravel with the sand and silt layer. The thickness of this formation is 1200 m and the alluvial deposits are among Hezardareh formation.
