Department of Earth and Planetary Sciences University of California Santa Cruz California USA, Department of Earth and Planetary Sciences Santa Cruz California USA, Institut de Physique du Globe de Strasbourg - IPGS - UMR7516, Observatorio Vulcanológica y Sismológico de Costa Rica Universidad Nacional Heredia Costa Rica, Department of Geology University of South Florida Tampa Florida USA, Jet Propulsion Laboratory Pasadena California USA, School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia USA