1. PhD Student, Geological Engrg. Program, Univ. of Wisconsin-Madison, Madison, WI 53706. E-mail: hyjo@students.wisc.edu
2. Assoc. Prof., Dept. of Civ. Engrg., Ritsumeikan Univ., Kusatsu, Shiga 525-8577, Japan. E-mail: tkatsumi@se.ritsumei.ac.jp
3. Prof., Geological Engrg. Program, Univ. of Wisconsin-Madison, Madison, WI 53706. E-mail: benson@engr.wisc.edu
4. Prof., Geological Engrg. Program, Univ. of Wisconsin-Madison, Madison, WI 53706. E-mail: edil@engr.wisc.edu