1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering,University of California at Davis, Davis, CA 95616 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, University of California at Davis, Davis, CA 95616.
3. Senior Engineer, Fugro West, Inc., Oakland, CA 94607.
4. Principal Engineer, Fugro West, Inc., Oakland, CA 94607.