Institution: | University of North Carolina, Department of Geological Sciences, CB#3315,;Mitchell Hall, Chapel Hill, NC 27599-3315, USA. E-mail: Geophysical Services, Russian Academy of Science, Petropavlovsk-Kamchatsky, Russia. E-mail:;Dipartimento di Scienze della Terrra, Universita' di Firenze, via LaPira, 4, I-50121;–Firenze, Italy. E-mail: |