Development of nga-sub ground motion model in Japan for 5%-damped pseudo-spectral acceleration

This paper summarizes the preliminary results of the development of empirical ground motion models (GMM) for subduction earthquakes in Japan. The model is based on the previous studies (Si and Midorikawa 1999; Midorikawa and Ohtake 2004), and updated by using the extensive and comprehensive subduction database in Japan by Pacific Engineering Research Center. A GMM was developed for the RotD50 horizontal components of peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped elastic pseudo-absolute acceleration response spectral ordinates (PSa) at the selected periods ranging from 0.01 to 10 sec. The model includes terms and predictor variables considering tectonic setting (i.e. interface and intra-slab), hypocenter depths, magnitude scaling, distance attenuation, and site responses. The magnitude scaling derived in this study is well constraint by the data observed during the large-magnitude interface events in Japan (i.e. 2003 Tokachi-Oki earthquake, 2011 Tohoku earthquake) for different periods. The developed GMPE covers subduction earthquakes occurred in Japan for magnitudes ranging from 5.5 to as large as 9.1 with distances less than 300 km from the source. The results presented in this paper are preliminary ones, further improvement will be made soon.