Affiliation: | Geophysical Laboratory, Aristotle University of Thessaloniki, PO Box 352-1, GR 54006,;Greece. E-mail: Department of Earth Sciences, University of Trieste, Italy;Centro Ricerche Sismologiche, Intituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy;The Abdus Salam International Centre for Theoretical Physics, SAND Group, Trieste, Italy |