1. LTHE, Grenoble Univ; and, Ingenieur, GeophyConsult, BP 231, 73374 Le Bourget du Lac Cedex, France.
2. LTHE, Grenoble Univ., BP 53, 38041 Grenoble Cedex 09, France (corresponding author).
3. Ph.D. Student, LTHE, Grenoble Univ., BP 53, 38041 Grenoble Cedex 09, France.
4. LTHE, Grenoble Univ.; and, Assistant Professor, Dept. of Civil Engineering, National Taipei Univ. of Technology, 1, Sec. 3, Chung-Hsiao East Road, Taipei, 106, Taiwan.