The 2002-2003 submarine gas eruption at Panarea (Aeolian Islands, Italy): study of the seafloor and implications for volcanic hazard assessment.

Intense submarine gaseous exhalation, which produced a spectacular submarine fumarolic field, has started since November 2002 in the Panarea volcanic complex, which includes Dattilo, Panarelli, Lisca Bianca, Bottaro and Lisca Nera islets (Aeolian Islands, Italy). The gas eruption at Panarea occurred in coincidence with the parossistic volcanic eruption at Stromboli island, located just few tens of kilometres to the north, and the Mt Etna eruption. This contemporaneity imposes to carefully consider the volcanological implications of such phenomenon, as Panarea is currently considered an extinct volcano.Submarine volcanic activity in the Aeolian area has been known since Roman times, and several historians reported exhalation episodes and submarine eruptions, also in coincidence with eruptions at Mt Etna and Stromboli.Recent volcanological, structural, geochemical and geodetical surveys on Panarea island have identified a positive gravimetric anomaly, the presence of tectonic discontinuities and several centres of geothermal fluid emission, illustrating the presence of an active geothermal system beneath the volcano.We used the Marine Digital Terrain Model (MDTM), purposedly performed to highlight the bathymetry with a 0,5 m precision, detailed surveys by scuba diving prospections and GPS data, to study the exhalation centres and the morphological-structural features of the seafloor with the aim to clarify the relationships between gaseous exhalation, volcanological submarine structures and crustal deformations in this area.