1. Postdoctoral Fellow, Dept. of Civil, Architectural, and Environmental Engineering, Cockrell School of Engineering, Univ. of Texas at Austin, 301 E. Dean Keeton St. Stop C1700, Austin, TX 78712-0273; presently, Postdoctoral Fellow, Dept. of Physical Geography, Faculty of Geosciences, Utrecht Univ., Willem C. van Unnikgebouw, Heidelberglaan 2, 3584 CS, Utrecht, Netherlands.
2. Assistant Professor, Dept. of Civil, Architectural, and Environmental Engineering, Cockrell School of Engineering, Univ. of Texas at Austin, 301 E. Dean Keeton St. Stop C1700, Austin, TX 78712-0273 (corresponding author).