1. Department of Earth and Planetary Sciences, University of California - Riverside 1 , Riverside, CA , USA
2. Department of Earth Sciences, University of Delaware 2 , Newark, DE , USA
3. Department of Natural Resources, Washington Geological Survey 3 , Olympia, WA , USA
4. School of Earth and Sustainability, Northern Arizona University 4 , Flagstaff, AZ , USA
5. Department of Earth and Environmental Sciences, University of Minnesota 5 , Twin Cities, Minneapolis , USA
6. Department of Geography, University of Oregon 6 , Eugene, OR , USA