GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 3.1 15 (Vulcano, Lipari and Salina) are aligned along a regional strike-slip fault having a NNW-SSE trending, cutting also the Etna volcano. The submarine volcanic districts of the Tyrrhenian sea have been recently analyzed also as possible geothermal resources, considered the high values of heat flow related to these volcanic structures (Signanini et al. , 2006). In the Aeolian Arc the volcanic activity was explicated with four main phases, ranging in age from 1-1.3 My B.P. at the Sisifo seamount and at the Filicudi volcanic island. From 0.8 My B.P. to recent times shoshonitic and calcalkalyine lavas, consisting of basalts, andesitic basalts and rhyolites have been erupted in the volcanic complexes, both subaerial and submarine. The volcanic edifice of the Stromboli island started to form about 110 ky ago. The volcano shows symmetric flanks and a conical shape and has an average elevation of about 927 m above sea level. It represents the emerged part of an important volcanic edifice, high more than 3000 m. The eruptive activity, typically poliphasic, has controlled a stratigraphic architecture characterized by overlapping of different volcanic products (lavas and pyroclastites). The formation of the volcano started about 200 ky B.P. in the north-eastern sector of the island with the growth of a volcanic edifice now completely eroded, whose central neck is represented by the Strombolicchio inlet. About 100 ky B.P. in correspondence to the present-day volcanic edifice, a new volcano started to grow (Paleostromboli I), reaching a height of 400 m; a great part of this volcano was downthrown after Fig. 1 - Subbottom Chirp line Stromboli esx (a) and corresponding geologic interpretation (b). The line has been processed by using the Seisprho software (licensed by CNR-ISMAR, Istituto per la Geologia Marina, Sezione di Bologna). Note the occurrence of a thick volcanic acoustic basement related to the Stromboli volcanic lavas. a) b)