1. School
of Earth Sciences, The Ohio State University, 125 S Oval Mall, Columbus, Ohio 43210, United States
2. U.S. Geological Survey, 3215
Marine Street, Boulder, Colorado 80303, United States
3. Institute
of Arctic and Alpine Research (INSTAAR), 4001 Discovery Drive, University of Colorado at Boulder, Boulder, Colorado 80309, United States
4. Department
of Civil, Environmental, and Geo-Engineering, University of Minnesota, 500 Pillsbury Drive Southeast, Minneapolis, Minnesota 55455, United States