1. Department of Physics and Geology, Università di Perugia, via Pascoli, 06123, Perugia, Italy
2. Institute of Geosciences and Earth Resources, National Research Council of Italy, 56124, Pisa, Italy
3. Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada
4. Department of Engineering and Geology, Università degli Studi G. D'Annunzio, 66100 Chieti, Pescara, Italy
5. Dipartimento di Scienze della Terra - Universita' Sapienza di Roma, 00185 Roma, Italy
6. Department of Earth, Environment and Life Sciences – DISTAV, Università di Genova, 16132 Genova, Italy