[1] Univ Texas Austin, Jackson Sch Geosci, Dept Geol Sci, Austin, TX 78712 USA
[2] Univ Calif Los Angeles, Joint Inst Reg Earth Syst Sci & Engn, Los Angeles, CA 90095 USA
[3] Univ North Dakota, John D Odegard Sch Aerosp Sci, Dept Atmospher Sci, Grand Forks, ND 58202 USA
[4] Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA
[5] Brown Univ, Dept Earth Environm & Planetary Sci, Providence, RI 02912 USA
[6] Univ Nevada, Nevada Seismol Lab, Reno, NV 89557 USA