1. Graduate School of Science and Engineering; Kagoshima University; Kagoshima 890-0065 Japan
2. Department of Earth and Environmental Sciences; California State University, 2576 E. San Ramon Avenue, Mail Stop ST-24; Fresno California 93740-8039 USA
3. Faculty of Natural System; Kanazawa University, Kakuma-machi; Kanazawa 920-1192 Japan
4. Department of Safety System Construction Engineering; Kagawa University; Takamatsu Kagawa 761-0396 Japan
5. Faculty of Education; Saitama University, Shimo-Okubo 255; Saitama 338-8570 Japan