1. Assistant Professor, Dept. of Civil and Environmental Engineering, 105D Patton Hall, Virginia Tech, Blacksburg, VA 24061 (corresponding author).
2. Consultant, McKinsey & Company, Chicago, IL 60603.
3. Professor Emeritus, Dept. of Civil and Environmental Engineering, Y2E2 Building Room 231, Stanford Univ., Stanford, CA 94305.
4. Professor, Dept. of Civil and Environmental Engineering, Blume Earthquake Engineering Center Room 118, Stanford Univ., Stanford, CA 94305.
5. Professor and Chair, Dept. of Civil and Environmental Engineering, 400 Snell Engineering Center, 360 Huntington Ave., Northeastern Univ., Boston, MA 02115.