Abstract
In our previous paper we had estimated engineering bedrock waves, in which local site effects of surface geology are removed, by using strong motion records of 18 earthquakes observed at 12 boreholes sites deployed in the 20km X 20km region in Sendai. The objective of this paper is to represent acceleration Fourier spectra of the engineering bedrock waves by the statistical model which reflects recent seismological studies. First we modeled the spectra which takes account of the amplification factor from the seismological bedrock to the engineering bedrock on to Boore's model, in which source spectra are modeled by the so-called ω^<-2> model with a high-frequency decay parameter fmax. Second we identified the model parameters by the step-by-step identification method proposed in this study and carried out regression analyses for these identified parameters. As a result, we successfully obtained a physically meaningful new statistical spectral model for engineering bedrock waves which reflects the characteristics of the source, path and site for the Sendai region.
