1. Graduate Student, Dept. of Architecture and Architectural Engineering, Kyoto Univ., Gokasho, Uji, Kyoto 611-0011, Japan (corresponding author).
2. Research Fellow, National Research Institute for Earth Science and Disaster Prevention, Shinjimicho, Miki, Hyogo 673-0515, Japan.
3. Professor, Disaster Prevention Research Institute, Kyoto Univ., Gokasho, Uji, Kyoto 611-0011, Japan.