1. Department of Geophysics–Geothermics, University of Athens, Panepistimiopolis, 157 84 Zografou, Greece
2. Key Laboratory of Earthquake Prediction, Institute of Earthquake Forecasting, China Earthquake Administration, Beijing, China
3. Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, Roma, Italy