Walter A Robinson, North Carolina State University Raleigh, Raleigh, NC, United States, Yochanan Kushnir, Columbia Univ, Palisades, NY, United States, Mingfang Ting, Lamont Doherty Earth Observ, Palisades, NY, United States and Dong Lee, Lamont -Doherty Earth Observatory, Palisades, NY, United States