GR08 -- Poster Presentation
Gravity tide in the Neapolitan volcanic area
Umberto Riccardi1,2, Giovanna Berrino3, Gennaro Corrado1,
Anna Albano1, Teodoro Esposito1
1Dipartimento
di Scienze della Terra, Università “Federico II” di Napoli,
Naples, Italy. e-mail: umbricca.unina.it, corrado@unina.it,
teoespos@unina.it
2Institut de Physique du Globe de Strasbourg-(UMR 7516 CNRS-Université
de Strasbourg), Strasbourg Cedex, France.
3Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli
Osservatorio Vesuviano, Naples ,Italy. e-mail: berrino@ov.ingv.it.
Recording gravity stations are operating in the Neapolitan volcanic areas
aimed at the geophysical monitoring of the volcanic activity. The
availability of reliable models of the gravity tide in a volcanic area is the
main condition to extract from the gravity records the signal possibly
associated to volcanic sources.
Gravity records, collected in different time intervals, respectively during
90’s at Vesuvio and recently at Napoli stations have been analyzed. The sites
where spring gravimeters (LCR, G and D) are recording are also sites
surveyed by absolute and relative gravity measurements carried out to
monitor the volcanic activity.
The records have provided models of the gravity tide for both the areas; the
knowledge of the gravity tide is also useful to a precise reduction of discrete
absolute and relative measurements. Moreover the residual tidal vectors
have been computed in order to take into account the contribution of the
ocean tide loading to the body tide. The WDD Earth Model has been
adopted as a reference in the computation of the residual vectors for the
main tidal waves. The components of such residuals provide information
about the sensitivity and reliability of the scale factors adopted to calibrate
the gravimeters.