Abstract
It is thought that the Tonankai-Nankai Eq. occurs with certainly in the first half of this century. There is a possibility that we have higher tsunamis than the current estimation when next earthquake has bigger magnitude than the current estimation. Also, we found that some local tsunamis become much higher in the case of bigger magnitude earthquake. This is a result given by case study of Hokaido Tokachi off Eq. In this study, we try to find out relation between earthquake magnitude and tsunami height, and we try to be clarified why tsunamis due to a bigger magnitude eq. become much higher locally. Also we try to suggest social response in the next Nankai Eq. in consideration on locality of tsunami amplification by earthquake magnitude.
