[1] Univ Houston, Dept Earth & Atmospher Sci, Houston, TX USA
[2] Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA
[3] Acad Sinica, Inst Earth Sci, Taipei, Taiwan
[4] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA
[5] Jet Prop Lab, Pasadena, CA 91109 USA