1. Senior Seismic Research Engineer, John A. Martin & Associates, Inc., 1212 S. Flower St., Los Angeles, CA 90015; formerly, Graduate Student, Univ. of Memphis, Memphis, TN 38152. E-mail: arzhang@johnmartin.com
2. Emison Professor of Civil Engineering, The Univ. of Memphis, Memphis, TN 38152.
3. Visiting Associate Professor, Univ. of Wisconsin–Madison, Madison, WI; Associate Professor of Civil Engineering, Marquette Univ., Milwaukee, WI 53233.