GNGTS 2015 - Atti del 34° Convegno Nazionale

GNGTS 2015 S essione 1.3 143 PRELIMINARY MICROTREMOR SURVEY RESULTS IN SALINELLE MUD VOLCANOES: PATERNÒ, ITALY F. Panzera 1 , S. Sicali 2 , G. Lombardo 1 , S. Imposa 1 1 Dip. di Scienze Biologiche, Geologiche e Ambientali – Sez. di Scienze della Terra, Università di Catania, Italy 2 Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo, Catania, Italy Introduction. The gas emissions observed at Etna, are linked to the persistent emission of a huge volcanic plume, in the summit craters during both quiescent and eruptive magma degassing, and others gas manifestations such as mud volcanoes and soil degassing which occur in peripheral sectors of the volcano (Allard et al. , 1991; Caracausi et al. , 2003; Aiuppa et al. , 2007). The Salinelle of Paternò are mud volcanoes located in the lower southern western flank of Mt. Etna, that it is one of the largest basaltic active volcano in Europe (Fig. 1a). The Salinelle are characterized by emissions of muddy and frequently salty water which sometime create specific pseudo-volcanic structures known as mud volcanoes. Their formation is due to the presence, in the subsoil, of over-pressured gases that escape upward through permeable rocks and structural and/or lithologic discontinuities, carrying to the surface a mixture of water, mud, hydrocarbon fluids and lithoid fragments that is emitted as a flowing liquid (Aiuppa et al. , 2004). The water emitted at mud volcanoes frequently contains salty solutions that precipitate forming deposits. For this reason, in certain areas of Italy they are named Salinelle . Such phenomena have been observed and studied in different parts of the world and in different Fig. 1 – a) Simplified geological map of Mt. Etna showing the main structural features (RFS Ragalna fault system, TFS Timpe fault system, PF Pernicana fault). b) Simplified geo-lithologic map of the Salinelle area.