A Study on the Strong Motion Prediction Method based on the Characteristics Estimated by Generalized Inversion Technique

Abstract

We need a method that can predict strong ground motions with sufficient accuracy at any target sites. So far, however, our knowledge about the characteristics of source, path, and site factors of the observed strong motions has not been fully utilized. First, we performed the analysis to investigate the properties of the factors mentioned above based on a generalized inversion technique (GIT) on Fourier spectra of strong motion networks deployed in Japan, then we tried to model not only spectral amplitude but also phase in spectra. Next, we constructed a procedure for predicting the strong motions considering both the spectral difference between the whole duration of motion and the S-wave portion and the effects of soil nonlinearity. Finally, we confirmed the proposed method worked well for the largest aftershock (Mw7.8) of the 2011 Tohoku earthquake with a special consideration of its smaller stress drop as a regional source characteristic.