1. Physical and Environmental Sciences, Concord University , Athens, WV , USA
2. Department of Geology, SUNY Buffalo , Buffalo, NY , USA
3. CCI, University of Maine , Orono, ME , USA
4. Lamont-Doherty Earth Observatory, Columbia University , Palisades, NY , USA
5. Alaska Volcano Observatory, US Geological Survey , Anchorage, AK , USA