摘要：The Horizontal-to-Vertical Spectral Ratio (HVSR) technique is one of the most suitable tools for estimating the geological effect on ground motion. The main target of this study is to estimate the site effect and the fragility index value at the new Tiba City proposed extension. To achieve these targets, 21 ambient vibration recordings were conducted with 1 km grid to cover the investigated area. The estimated predominant frequency (f0) distribution is a relative uniform and occurs at low frequency, ranging from 0.35 to 0.75 Hz and its maximum corresponding amplitude of seismic wave (A0) starts from 3.1 up to 6.5. The qualitative interpretation of loose sedimentary cover thickness is large (136 to 410 m with average ~270 m) that coincided with occurrence of (f0) at low level. The fragility index for the ground (Kg) at each measured site was computed depending on the estimated H/V amplitude and corresponding (f0), and found to range from 17 to 118 across the investigated area. The highest values of Kg were obviously found in the northeastern part of the proposed site, where the highest amplification factor and the lowest fundamental frequency are found.
关键词：Tiba City;HVSR method;fundamental frequency;amplification;fragility index
