1. Department of Mechanical and Civil Engineering California Institute of Technology Pasadena CA USA
2. Seismological Laboratory California Institute of Technology Pasadena CA USA
3. Now at Institute of Geophysics ETH Zürich Zürich Switzerland
4. Now at Université Côte d'’Azur, IRD, CNRS, Observatoire de la Côte d'Azur Géoazur France