Development of NGA-Sub ground-motion prediction equation of 5%-damped pseudo-spectral acceleration based on database of subduction earthquakes in Japan

We developed an empirical ground-motion model for subduction earthquakes in Japan. The model is based on the extensive, comprehensive subduction database for Japan by the Pacific Earthquake Engineering Research Center. The model predicts the RotD50 horizontal components of peak ground acceleration, peak ground velocity, and 5%-damped elastic pseudo-spectral acceleration ordinates in the selected periods ranging from 0.01 to 10 s. The model includes predictor variables considering tectonic setting (i.e. interplate and intraplate), the hypocentral depths, magnitude scaling, distance attenuation, shallow soil, and the basin responses. The magnitude scaling of interplate earthquakes is well constrained in Japan for different periods because the database includes the well-recorded large-magnitude events (i.e. the 2003 Tokachi-Oki and 2011 Tohoku earthquakes). The developed ground-motion prediction equation covers the subduction earthquakes that occurred in Japan for moment magnitudes ranging from 5.5 to 9.1 with closest distances to the fault of less than 300 km.