USING THE H/V SPECTRAL RATIO FORESTIMAT ING THE VULNERA BILITYINDEX OF A URBAN AR EA

The subsurface topography a nd the dynamic specification of soils have impor tant effect on the ground motion response. During the age of cities, the building have constructed by t he different techniques, materials, styles and standard codes. The researches have shown that the buildings have different response to earthquake related of their materi als and design rules. The soil layer specifications are recognizing by different geotechnical and geophysi cal methods, including geotechnical and geophy sical as well as spectral ratio. Horizontal-to-vertical spectral ratio (H/V) of microtremore was introduced by Nakamura (1989). This method is very usable in site characterization studies due to its low budget and easy use. In this paper, it has presented a method for estimating the degree of vulnerability of structures using spectral ratio H/V. In a vulnerability study in the city of Shi raz, the predominant frequencies are derived for the different parts of the city. These data have used to define a coefficient of vulnerability for the earth. For this purpose, 11 different building such masonry, steel or con crete structures were selected. The main freque ncy and amplification of microtremor H/V spectral ratio for building has been obtained. Furthermore, the resonant frequency and amplification factor of the ground h ave been calculated. The vulnerability index of soil Kg and vulnerability of building Kb were defined. com parison of these coefficients it was recognize d a damage factor η of building during the earthquake. T his parameter leads to a fast and inexpensive method for preparing a disaster program for an urban area. In this paper, the damage rate of different buil ding at Shiraz City was obtained. In addition, the damage po tential of all the city area was calculated.

کلیدواژه ها:

Vulnerability ، Disaster Management ، H/V Spectral Ratio ، Microtremor ، Microzonation