1. Departamento de Informática, Instituto Dom Luiz (IDL) and the Space & Earth Geodetic Analysis Laboratory (SEGAL), Universidade da Beira Interior (UBI), Covilhã, Portugal
2. Swiss Seismological Service, Zürich, ETH-Zürich, Switzerland
3. Instituto de Telecomunicações and the Departamento de Informática, University of Beira Interior, Covilhã, Portugal
4. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
5. Department of Geophysics, University of Stanford, Stanford, CA, USA
6. Instituto Dom Luiz, Faculdade de Ciencias, Universidade de Lisboa, Lisbon, Portugal