1. Department of Geosciences University of Arizona Tucson AZ USA
2. Lunar and Planetary Laboratory University of Arizona Tucson AZ USA
3. Geophysical Institute University of Alaska Fairbanks Fairbanks AK USA
4. Department of Physics University of Alaska Fairbanks Fairbanks AK USA
5. Department of Computer Science University of Montana Missoula MT USA
6. School of Geography, Development, and Environment University of Arizona Tucson AZ USA