1. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA 95616 (corresponding author).
2. Peter S. Higgins and Associates, 30765 Pacific Coast Highway #117, Malibu, CA 90265.
3. Engineer, Forell Elsesser Engineers, 160 Pine St., San Francisco, CA 94111.
4. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of California, Davis, CA 95616.
5. Engineer, Peter S. Higgins and Associates, 30765 Pacific Coast Highway #117, Malibu, CA 90265.