1. Dep. of Geomechanics Sandia National Laboratories PO Box 5800, Mail Stop 0750 Albuquerque NM 87185‐0750 USA
2. Dep. of Applied Systems Analysis and Research Sandia National Laboratories PO Box 5800, Mail Stop 0747 Albuquerque NM 87185‐0747 USA
3. Dep. of Natural Resources Management and Environmental Sciences California Polytechnic State Univ. 1 Gran Ave. San Luis Obispo CA 93407 USA