Applicability of the Ground Motion Prediction Equations to the 2011 Tohoku earthquake, M9.0, Japan

To investigate the applicability of Ground Motion Prediction Equations to mega earthquakes, the author applied the GMPEs developed using pre-2011 records (up to M8-class) to the 2011 Tohoku earthquake (Mw9.0). The major results are as follows: 1) definition of source-to-site distance causes large difference not only in the estimation at near-source distances of crustal earthquakes but also for mega-thrust earthquakes. 2) GMPEs using fault distance have tendencies to overestimate for mega earthquake and saturation rate at near-source distances would be revised. 3) GMPEs using Equivalent Hypocentral Distance generally agree with the Tohoku earthquake (can extrapolate to M9). 4) As the other important factors, nonlinear Mw-term and nonlinear soil amplification factors must be modeled to improve the applicability of GMPEs to mega earthquake.