THE NECESSITY OF 2D/3D SITE EFFECT STUDIES IN BIG CITIES OF IRAN:PREMILINARY RESULTS OF TEHRAN EXPERIMENT
- سال انتشار: 1398
- محل انتشار: هشتمین کنفرانس بین المللی زلزله شناسی و مهندسی زلزله
- کد COI اختصاصی: SEE08_383
- زبان مقاله: انگلیسی
- تعداد مشاهده: 310
نویسندگان
Ph.D. Candidate, IIEES, Tehran, Iran
Associate Professor, IIEES, Tehran, Iran
Ph.D., Universite Grenoble Alpes, Grenoble, France
Ph.D., Universite Grenoble Alpes, Grenoble, France
چکیده
Iran is one of the most seismically active countries in the world due to the collision between the Arabian and Eurasian plate. According to the 4th version of Iranian seismic building code (BHRC, 2016) 14 out of 18 metropolises of Iran (Metropolis in Iran defined as the large city which is a signifiant economic, political, and cultural center with over 1 million (or sometimes 500,000) inhabitants.) are located in areas with high and very high seismic risk hazard. Most of these cities are located along valleys on soft unconsolidated sediments, a very common example of a 2D structure. Based on many numerical studies, these structures can cause amplifications significantly higher than the corresponding 1D value (e.g. Bard & Bouchon, 1985). That means even moderate earthquakes can make causality for more than 25 million peoples living in these areas.In recent years, a series of studies have been conducted in metropolises such as Tabriz (Haghshenas et al., 2006) and Mashhad (Akbari et al., 2011). However none of these studies have taken into account the 2D/3D effects. These effects are strongly depends on the geometry of the valley. In shallow valleys, the wave-field is dominated by laterally propagating surface waves generated at the valley edges while in deeper valleys the interference between surface waves with vertically propagating waves gives rise to the evolution of a 2D resonance pattern (Roten et al., 2006). Any study without consideration these multidimensional site effects could lead to an underestimation of ground motions. Tehran, is an alluvial basin lies on a seismically active zone of northern Iran. As a road map for such studies in Iran, we started to evaluate 3D modeling of Tehran alluvial deposits with ambient vibration techniques. Since the impact of an earthquake is strongly linked to the seismic wave velocity in the subsurface structure, shear wave velocity represents the most important parameter of the geophysical model. In this regard, surface wave methods of ambient vibration techniques are very common techniques to retrieve the shear-wave velocity profiles. For using these methods, new campaigns of noise measurement in Tehran Started from 2017 and up to now 26 arrays and around 300 single station measurements have been carried out in the city. The single station measurements has been carried on following the SESAME H/V user guidelines (SESAME, 2004) to verify preliminary evaluation about soil behavior in Tehran. Also in places with deep impedance contrast, single station measurements could be able to extracted absolute value of the ellipticity in a restricted frequency range (Hobiger et al., 2009).کلیدواژه ها
2D/3D Site effects, Surface Waves, Ambient noise, Tehranاطلاعات بیشتر در مورد COI
COI مخفف عبارت CIVILICA Object Identifier به معنی شناسه سیویلیکا برای اسناد است. COI کدی است که مطابق محل انتشار، به مقالات کنفرانسها و ژورنالهای داخل کشور به هنگام نمایه سازی بر روی پایگاه استنادی سیویلیکا اختصاص می یابد.
کد COI به مفهوم کد ملی اسناد نمایه شده در سیویلیکا است و کدی یکتا و ثابت است و به همین دلیل همواره قابلیت استناد و پیگیری دارد.