1. Geology, Minerals, Energy, and Geophysics (GMEG) Science Center, U.S. Geological Survey, MS 901, 345 Middlefield Road, Menlo Park, California 94025, USA
2. Mineral Deposits Research Unit, University of British Columbia, Vancouver, B.C. V6T 1Z4, Canada
3. U.S. Geological Survey, Box 25046, MS 973, Federal Center, Denver, Colorado 80225, USA
4. Oregon State University, Corvallis, Oregon 97331, USA
5. Volcano Science Center, U.S. Geological Survey, MS 910, 345 Middlefield Road, Menlo Park, California 94025, USA