GNGTS 2013 - Atti del 32° Convegno Nazionale

of fluids rich in CO 2 then this is easily relatable to an episode of out-gassing from the deepest portion of the magmatic system. Alternatively, this behaviour could be related to a magmatic source that degas constantly compared to isolated periods as previously thought. In particular a slow lifting of the soil is started in 2004 and continues to this day and is characterized by a deformation longer and slower than previous episodes of lifting (Troise et al. , 2007). Cioni et al. (1989) suggest that the relationship CO 2 /H 2 O behave like a true precursor of the crisis of 1984 as it was thought that a geochemical indicator for monitoring the boiling hydrothermal confined aquifer. In this first interpretation, the decrease in the ratio CO 2 /H 2 O observed before the crisis of 1984 and even before the smaller crisis that followed, it could indicate an increase in the boiling process and overpressure of the aquifer due to an increase in the flow of heat from magmatic body. Unlike Caliro et al. (2007) show that the ratio CO 2 /H 2 O is controlled by the mixing zone of magmatic gases and liquid of meteoric origin. The decrease of the ratio CO 2 /H 2 O corresponds to periods in which there is a low flow of magmatic component and underpressure of hydrothermal plume in agreement with the subsidence of the soil always accompanied by periods of decrease of the ratio gas/vapor. Pisciarelli geological setting. The Pisciarelli area is located slightly outside the caldera rim of the Solfatara with NO direction. This area is characterized by the presence of fractures and is affected by phenomena of emission of gases and fluids. The main component of the fumaroles is H 2 O followed by CO 2 and H 2 S and with a range of temperature between 100-110 °C (Chiodini, 2009). During field surveys in the Pisciarelli made during the year 2006 were observed, compared to similar surveys conducted in the past (the year 2005), changes in the most affected by the Fig. 1 – Gases and fluids in Pisciarelli area. 247 GNGTS 2013 S essione 1.3