1. Research Associate, Bureau of Economic Geology, The Univ. of Texas, Austin, TX 78713; formerly, Postdoctoral Associate, Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (corresponding author).
2. Dept. Head, Professor of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
3. Professor and Director, Geotechnical Institute, Technical Univ. of Berlin, Sek. TIB1-B7, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
4. CDM Geotechnical Services Div., Cambridge, MA 02139.