Department of Physics, University of Salerno, Via S. Allende, Baronissi (SA), 84081 Italy ; INFN - Laboratori Nazionali del Gran Sasso, S.S. 17 BIS km. 18.910, Assergi (AQ), 67010 Italy
Department of Physics, University of Salerno, Via S. Allende, Baronissi (SA), 84081 Italy ; INFN - Laboratori Nazionali del Gran Sasso, S.S. 17 BIS km. 18.910, Assergi (AQ), 67010 Italy
Department of Geology, Yale University, 210 Whitney Ave, New Haven, CT 06520-8109 United States
Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, Roma, 00143 Italy
Department of Physics, University of Salerno, Via S. Allende, Baronissi (SA), 84081 Italy