1. Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005, Paris, France;
2. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
3. Swiss Seismological Service, ETH Zürich, Zürich, Switzerland
4. Institut Supérieur de l'Aéronautique et de l'Espace SUPAERO, Toulouse, France
5. Institute of Geophysics, ETH Zürich, Zürich, Switzerland
6. Bensberg Observatory, University of Cologne, Bergisch Gladbach, Germany
7. Department of Electrical and Electronic Engineering, Imperial College London, London, United Kingdom