1. Department of Earth and Planetary Sciences, Washington University in St. Louis, Campus Box 1169, 1 Brookings Drive, Saint Louis, Missouri 63130‐4899 U.S.A., sydneydybing@gmail.com
2. U.S. Geological Survey, Albuquerque Seismological Laboratory, P.O. Box 82010, Albuquerque, New Mexico 87198‐2010 U.S.A.