1. Chief Geotechnical Engineer, Ninyo & Moore Geotechnical & Environmental Sciences Consultants, 475 Goddard, Ste. 200, Irvine, CA 92618.
2. Professor and Vice Chair, Civil and Environmental Engineering Dept. 5731 Boelter Hall, Univ. of California, Los Angeles, CA 90095 (corresponding author).
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA 95616.
4. Professor, Dept. of Civil Engineering, National Chung-Hsing Univ. 250 Kuo Kuang Rd., Taichung, Taiwan.