Evidence of active deformation of the Panarea Volcano from GPS data

Abstract

Between November 2nd and 3rd 2002 a shallow submarine gas eruption occurred in the area between Lisca Bianca, Bottaro and Lisca Nera islets located about 2.5 km from Panarea Island, in the Aeolian volcanic archipelago, Southern Italy. To estimate the current crustal deformation of this active volcanic area and to evaluate its volcanic hazard, a local GPS network was set up and repeatedly surveyed in the time span December 2002 - October 2005, with the aim to monitor the evolution of the crustal deformation related with the exhalative crisis. The local GPS network consists in 11 GPS stations located in the Panarea archipelago. First results show vertical movements and an active strain, up to 20x 10-6 across the islets. Strain axes display NNW-SSE extension and ENE-WSW compression. We interpret these data as relative to the deflation of the area, after the exhalative crisis, along existing tectonic structures. Present day observation of the exhalative field confirm that the gas emission migrated from NE to NW oriented fractures, in agreement with the strain tensor changes with time, estimated through GPS data.