Abstract
This paper presents the result of multiple regression analysis of absolute acceleration response spectra with damping ratio of 5% of critical. Analyzed were 394 horizontal strong motion acceleration records obtained at 67 free field sites in Japan from 88 earthquakes with focal depth less than 60km. Because sensitivity of the Japanese SMAC accelerograph is appreciably low at the high frequency range, instrumental correction was performed on the original data. Each pair of two orthogonal horizontal components was combined in time domain to get the maximum value of absolute acceleration response spectra on the horizontal plane. The records were classified into three groups due to subsoil condition. Empirical formulae of attenuation of absolute acceleration response spectra with 5% damping ratio are proposed for three subsoil conditions.
