Gravity Tide at Mt.Vesuvius(Southern Italy): Correlations With Different Geophysical Data and Volcanological Implications.
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Accession number;01A0565402
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| Title;Gravity Tide at Mt.Vesuvius(Southern Italy): Correlations With Different Geophysical Data and Volcanological Implications. |
| Author;
BERRINO G
(Osservatorio Vesuviano, Naples, Ita)
RICCARDI U
(Univ. Naples, Naples, Ita)
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Journal Title;Journal of the Geodetic Society of Japan
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Journal Code:G0199A
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ISSN:0038-0830
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VOL.47;NO.1;PAGE.121-127(2001)
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| Figure&Table&Reference; |
| Pub. Country;Japan |
| Language;English |
| Abstract;Mt.Vesuvius is an active volcano located at the eastern boundary of Naples, Italy, in a densely populated area. Since the last eruption in March 1944, it is quiescent. Several geophysical studies are monitoring its activity. The volcano shows a generally low level seismicity, small ground deformation, gravity changes and a moderate gas emission. Since 1987 a recording gravity station operates on the volcano aimed at featuring the Earth tide transfer function in the area and continuous record of "non-tidal" gravity changes. Here we focus on the results obtained from gravity records starting from 1994, after a break of about three years. Accurate calibration procedures enesure a frequent check of the instrumentation. A First order correction for the ocean loading and atmospheric effects are applied on the gravity data. Well-constrained tidal parameters have been so determined for the main tidal waves. The results have been compared with those obtained from gravity records spanning 1959-61, 1961-65 and 1987-91 years. The temporal trend of the tidal parameters and gravity residuals have been then compared with some features of the volcanic dynamics, mainly the temporal gravity changes detected by absolute and relative measurements and the time evolution of the seismicity. A large decrease of tidal parameters was observed from 1959-61 to 1961-95, while two significant increases occur from 1991 to 1994 and from 1998 to 1999. The latter "anomalies" appear to be time-correlated with some gravity changes resulting from absolute and relative measurements, and with seismic crises which occurred in the area. The observed phenomena may be indicative of a larger deformation behaviour of the volcanic area probably due to the change of the mean mechanical properties of the volcano. (author abst.) |
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