1. Department of Civil Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
2. Department of Socio-Cultural Environment Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
3. Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University, Hokkaido, Japan
4. Coast Division, National Institute for Land and Infrastructure Management, Ibaraki, Japan