1. University of Nice Sophia Antipolis, CNRS, IRD; Observatoire de la Côte d'Azur, Géoazur UMR; Valbonne France
2. Now at the Department of Geological Sciences; University of Oregon; Eugene Oregon USA
3. Seismological Laboratory, Division of Geological and Planetary Sciences; California Institute of Technology; Pasadena California USA
4. Now at the Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography; University of California, San Diego; La Jolla California USA