Abstract
The objective of this study is to investigate in detail the characteristics of strong ground motions separated from Fourier spectra using the observed data by K-NET, KiK-net, and JMA seismic intensity meter Network in Japan.We found that our Q models are comparable to those of previous studies, and that Q models are dependent on regions in and around Japan. Brune (1970)’s stress drop has a magnitude dependence in between mainshocks and aftershocks (or smaller events in general), and short-period levels A are in good agreement with those of Satoh (2003), but not in good agreement with that of Dan et al. (2001) for crustal earthquakes. We also found that site amplifications are stable regardless of the observed period with some possibility of directional dependence, and that site amplification for a site has a standard deviation around 0.2-0.3 in the target frequency range.
