1. Lab. 3, Association for Disaster Prevention ResearchEmeritus of Kyoto University 138‐1 Tanaka‐Asukaicho Sakyo‐ku Kyoto 606‐8226 Japan
2. School of Civil and Environmental EngineeringUniversity of New South Wales Sydney NSW 2052 Australia
3. Department of Civil and Earth Resources EngineeringKyoto University Kyoutodaigaku‐Katsura 4 Nishikyo‐ku Kyoto 615‐8540 Japan