Abstract
In order to qualitatively study the Fourier spectral characteristics of strong motion earthquake records on becrock, the Fourier spectra of 17 accelerograms (4.3≤M≤7.1), which were recorded in Japan, were analyzed. The result of this study suggests that the averaged acceleration Fourier amplitude spectra on bedrock level can be considered to be nearly flat statistically during the periods 0.1sec and T_m=10^<-0.39M-1.7>) sec. This qualitative result agrees well with the characteristics of theoretical spectra calculated by propagating fault model. The period Tm and the corner frequency frequency (Savage, 1972) [3] also agree well for magnitude M≥6.0. These results also indicate that the averaged Fourier spectra of accelerograms observed at a given site should be similar in shape to the transfer function of that site.
