1. Unaffiliated
2. Earth and Planetary Sciences, University of California, Davis, California 95616, USA
3. Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
4. Department of Geology and Geological Engineering, South Dakota School of Mines and Technology, South Dakota 57701, USA
5. Department of Earth and Environmental Sciences, Michigan State University, Michigan 48824, USA
6. GeoSep Services, Moscow, Idaho 83843, USA