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PRELIMINARY SEISMIC MICROZONATION Of BOJNORD USING MICROTREMORS

عنوان مقاله: PRELIMINARY SEISMIC MICROZONATION Of BOJNORD USING MICROTREMORS
شناسه (COI) مقاله: SEE07_311
منتشر شده در هفتمین کنفرانس بین المللی زلزله شناسی و مهندسی زلزله در سال 1394
مشخصات نویسندگان مقاله:

Mohammad KHANDAN BAKAVOLI - Assistant Professor, University of Bojnord, Bojnord, Iran
Seyyed Hossein SAJJADI - M.Sc. Student, University of Bojnord, Bojnord, Iran

خلاصه مقاله:
Seismic hazard assessment of big cities is imperative to mitigate the potential damage and loss of life due to earthquakes. Local ground conditions substantially affect the characteristics of incoming seismic waves during earthquakes. Soft soil deposits amplify certain frequencies of ground motion and extend the duration of the motion, thereby increasing earthquake damage. Seismic waves are trapped in the soft soil layer and multi-reflection phenomenon occurs. As a result, the ground vibrates severely with a specific dominant period. This period is called the predominant period of the ground, and the vibration of structures on the surface is highly influenced by it.Microtremor observations can be used to determine the dynamic properties of a site and, hence, can be used for microzonation. In order to clarify the surface ground motion characteristics at Bojnord City, a microtremor measurement grid has been designed. Different 1-hour microtremor measurings during day and night have been carried out. The horizontal to vertical spectral ratio technique, also called Nakamura's method (Nakamura, 1989) or HVNR was used as a principal data processing procedure in order to extract the experimental transfer function of the site. Fundamental frequencies of the sites using HVNR have been extracted. Following this extraction, the city zonation considering the low-rise, mid-rise and high rise building has been carried out and finally distribution maps of site periods and peak ground acceleration throughout the city were developed.

کلمات کلیدی:
Microtremor, Microzonation, H/V, Spectrum

صفحه اختصاصی مقاله و دریافت فایل کامل: https://civilica.com/doc/1132512/