1. Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
2. Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI 48824, USA
3. School of Earth and Space Sciences, Peking University, Beijing 100871, China
4. Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA
5. EditSprings, Boston, MA 02445, USA
6. Earth, Planetary and Space Sciences, University of California Los Angeles, CA 90095, USA