1. McCormick Institute Professor and W.P. Murphy Professor of Civil and Mechanical Engineering and Materials Science, Northwestern University, 2145 Sheridan Road, CEE/A135, Evanston, IL 60208 e-mail:
2. Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208
3. Subsurface Flow and Transport Team Leader Computational Earth Science, EES-16, Sch. A, Los Alamos National Laboratory, Los Alamos, NM 87545
4. Los Alamos National Laboratory, Los Alamos, NM 87545