Difference Analysis of Site Dominant Frequencies Obtained from Response Spectra and Fourier Spectra of Earthquake Motion
The Horizontal-to-Vertical Spectral Ratio(HVSR)method for strong motion records is commonly used to evaluate a site's predominant frequency.Both the acceleration response spectrum and the acceleration Fourier spectrum are frequently employed to calculate the HVSR of strong motion records,but these two approaches often yield different results.To investigate the differences in predominant site frequency between the response spectrum ratio and the Fourier spectrum ratio,this study analyzes 16 stations from Japan's KiK-net network,where site conditions can be approximated using a one-dimensional site model.First,data processing methods for evaluating site predominant frequency were developed.These include S-wave interception,taper preprocessing,and automatic peak identification based on Gaussian fitting.The effects of damping ratio and smoothed bandwidth ratio on site frequency evaluation were examined.It was found that using a 10％damping ratio for the response spectrum and a smoothing bandwidth ratio of 20～40 for the Fourier spectrum yielded more accurate results.Next,the predominant site frequencies obtained from the ground motion acceleration response spectrum and Fourier spectrum were compared with the natural frequency calculated from the site soil model using the trans-fer function.The results indicate that the Fourier spectrum ratio provides a more accurate estimate of the predominant site frequency compared to the response spectrum ratio for most stations,particularly those located on Class Ⅱ,Ⅲ,and Ⅳ sites.However,a few specific stations showed better results when using the response spectrum method.
Strong motion recordsResponse spectrumFourier spectrumPredominant frequency of siteBandwidth ratioDamping ratio
万方数据
维普
