A New Ground Motion Prediction Equation for Japan Applicable up to M9 Mega-Earthquake

In this study we suggest a new ground motion prediction equation applicable up to the moment magnitude 9 using the strong motion records from the 2011 Tohoku-oki earthquake. We determined a base model with moment magnitude and the shortest distance from the source fault as parameters. In order to avoid overestimating amplitude atmagnitude larger than 8, we examined two models – a quadratic magnitude term and a linear magnitude term with a complete amplitude saturation term at someMw. We then adopt additional correction terms corresponding to amplification by deep sediments or shallow soft soils, and anomalous seismic intensity distribution in order to improve prediction.