University of Southern California, Department of Earth Sciences, Los Angeles, CA 90089-0740 United States
Observatoire Midi Pyrenees, Laboratoire de Dynamique Terrestre et Planetaire, Toulouse, 31400 France
CIRES, University of Colorado, Benson Earth Sciences Building Department of Geological Sciences, Campus Box 399 2200 Colorado Ave., Boulder, CO 80309-0399 United States
IGPP, SIO, UC San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225 United States