Gravity Changes and kinematic behaviour of the Island of Pantelleria in the Geodynamic Framework of the Sicily Channel (Southern Italy)

The island of Pantelleria is an active volcano located in the Sicily Channel (Southern Italy), in the middle of a continental rift system. Since the 1980s the island is periodically surveyed by means of geodetic techniques (levelling, EDM, GPS and high precise gravimetry) to monitor the local and regional volcanic dynamics. The analysis of the gravity data, collected during several field surveys from 1990 to 1998, have shown that the gravity field changes generally appear resulting by the superposition of short and long wavelengths, due to the combined effect of shallow and deep sources. Gravity changes fields also reflect, to some degree, the structural setting of the island as sketched by the Bouguer anomaly field which indicates that the island is constituted by a basement dislocated in two main blocks. These latter are also bordered by two lineaments, probably regional faults related to the global geodynamics of the Sicily Channel Rift Zone. Moreover, there is an inverse correlation between the gravity and height variations and their joined analysis implies that: i) Pantelleria appears to be divided in two blocks also from the kinematic behaviour; ii) the observed phenomena may be also ascribed to the influence of the geodynamics of the Sicily Channel. Moreover, a combined analysis of the time-space features of the horizontal ground deformation and gravity changes has been done to check if the characteristics previously detected are present in all the aspects of the kinematic behaviour of the island. On the basis of the previous conclusions the EDM data have been reprocessed for a proper comparison with the gravity data, the Bouguer anomaly and the altimetric data. This allows a joint interpretation taking also into account the structural setting and the geodynamics of the Sicily Channel to evaluate its influence on the local volcanic dynamics of the island.