The author summarize the attenuation characteristics of strong-motion records during the 2011 Tohoku earthquake and discuss the applicability of Ground Motion Prediction Equations (GMPEs) to mega earthquakes. The major results are as follows: 1) GMPEs adopting linear Mw term tend to overestimate when applying to mega earthquakes. The source term must follow the scaling of omega-square model. 2) Some of the GMPEs using fault distance also need to revise their saturation rate of amplitude when

more »

... luating mega earthquakes. 3) The different definition of source-to-site distance can cause not only the different attenuation characteristics but also the different source-term scaling in mega earthquakes, because the extensive fault of mega earthquake affect even in the distances farther than usually expected.