Using more than two hundred JMA-87 type strong-motion records we show that pseudo-velocity response spectra are noticeably different from Fourier acceleration spectra in several occasions because response spectra are sensitive to other frequency components or attenuation due to dispersion but insensitive to duration. Therefore, regression coefficients such as magnitude coefficients, attenuation coefficient, and site amplification factors for response spectra and Fourier spectra show clear differences. We conclude that physical characteristics of strong motion cannot always be represented by the regression coefficients for response spectra.
