1. Department of Earth and Planetary Sciences; University of California Santa Cruz; Santa Cruz California USA
2. Institut de Physique du Globe de Strasbourg; Université de Strasbourg/CNRS; Strasbourg France
3. School of Civil and Environmental Engineering; Cornell University; Ithaca New York USA
4. Laboratoire de Géologie; Ecole Normale Supérieure, CNRS; Paris France
5. Scripps Institution of Oceanography; University of California San Diego; La Jolla California USA
6. Centro Sismológico Nacional; Universidad de Chile; Santiago Chile