[1] Tech Univ Crete Polytechnioupolis, Sch Mineral Resources Engn, Appl Geophys Lab, Khania, Crete, Greece
[2] Univ Rome Tre, Signal Pro Cessing Telecommun & Econ Lab SP4TE, Via Vito Volterra 62, I-00146 Rome, Italy
[3] Univ Strasbourg, Inst Phys, Globe Strasbourg Ecole, 5 Rue Rene Descartes, F-67084 Strasbourg, France
[4] Univ Strasbourg, Observ Sci Terre, 5 Rue Rene Descartes, F-67084 Strasbourg, France
[5] Natl & Kapodistrian Univ Athens Panepistimiopoli, Dept Geophys, Zografos 15784, Greece
[6] Temple Univ, Weeks Chair Environm Geol, Dept Earth & Environm Sci, Philadelphia, PA 19122 USA
[7] Geophys Res Zipser, Str 1, D-76227 Karlsruhe, Germany
[8] Keele Univ Staffordshire, Sch Phys & Geog Sci, Appl & Environm Geophys Grp, Keele, Staffs, England