GNGTS 2011 SESSIONE 1.3 3 and a depth of about 1 to 20 km. The VT-A are generally take place previous to and in the first stage of eruptive activity. The VT-B events show a limited frequency content (1-8 Hz), a mean length of about 30 seconds and a local magnitude between -0.5 and 1.5. The hypocenters are limit- ed to an little area in the NW sector of the Marsili volcano, probably very near to an active crater. These event are very shallow (0-5 km) and don’t show any clear S wave arrivals. Despite the VT- A events, the VT-B take place in swarms (Fig. 3) with an average recurrence time of about 10 min- utes. The pressure signal recorded in the first experiment shows the occurrence of HFT. This events shows a boxfold envelope with sudden beginning and ending, a time duration of a few minutes and a dominant frequency of between 40 and 90 Hz. Similar signals were recorded at the Satsuma–Iwo- jima hydrothermal system (Ohminato, 2006) and ascribed to sudden vapor emission from water- filled underground pockets when the water temperature exceeded the ebullition point. We model the SDE events as transient waves excited by the normal modes of vibration of a resonator. In order to estimate their characteristic complex frequencies and improve the frequency spectra resolution, we applied the Sompi method. We found that this type of events are quasi-monochromatic and are prob- ably generated by oscillations of a steam-filled crack by unsteady choked flow. The collected information coherently show the persistence of active hydrothermal activity prob- ably located in the central portion of the volcanic edifice. Further investigations are needed to bet- ter constrain the relationships between the volcanic and the hydrothermal activities of the Marsili seamount also considering the evaluations in terms of both volcanic and industrial risks References Cella, F., Fedi, M., Florio, G. and Rapolla, A.; 1998: Gravity modelling of the litho-asthenosphere system in the Central Mediterranean, Tectonophys, 287, 117- 138. D’Alessandro, A., D’Anna G. Luzio D., Mangano G.; 2009: The INGV’s new OBS/H: analysis of the signals recorded at the Marsili submarine volcano. Journal of Volcanology and Geothermal Research, 183, 17-29. D’Anna, G., Mangano, G., D’Alessandro, A., D’Anna, R., Passafiume, G., Speciale, S, Amato, A.; 2009: Il nuovo OBS/H dell’INGV. Quaderni di Geofisica, 65, ISSN 1590-2595. Dekov, V.M. and Savelli, C.; 2004: Hydrothermal activity in the SE Tyrrhenian Sea: an overview of 30 years of research, Mar. Geol., 204, 161-185. Dekov, V. M., Kamenov, G. D., Savelli, C. and Stummeyer, J.: Anthropogenic Pb component in hydrothermal ochres from Marsili Seamount (Tyrrhenian Sea), Marine Geol., 229, (2006), 199-208. Faggioni, O., Pinna, E., Savelli C. and Schreider, A.A.; 1995: Geomagnetism and age study of Tyrrhenian seamounts, Geophys. J. Int., 123, 915-930. Lupton J, C de Ronde, M Sprovieri, E.T. Baker, P. P Bruno, F. Italiano, S. Walker, K. Faure), M. Leybourne, K. Britten, R. Greene; 2010: Active Hydrothermal Discharge on the Submarine Aeolian Arc: New Evidence from Water Column Observations. Jour. Geophys. Res., 116, B02102, doi:10.1029/2010JB007738 Mangano, G., D’Alessandro, A., D’Anna, G.; 2011: Long term underwater monitoring of seismic areas: Design of an Ocean Bottom Seismometer with Hydrophone and its performance evaluation, OCEANS, 2011 IEEE - Spain, ISBN: 978-1-4577-0086- 6, DOI: 10.1109/Oceans-Spain.2011.6003609. Marani, M.P., Gamberi, F., Casoni, L., Carrara, G., Landuzzi, V., Musacchio, M., Penitenti, D., Rossi, L. and Trua, T.; 1999: New rock and hydrothermal samples from the southern Tyrrhenian Sea: the MAR-98 research cruise. Gior. Geol., 61, 3-24. Verzhbitskii, E.V.; 2007: Heat Flow and Matter Composition of the Lithosphere of the World Ocean, Oceanology, 47, n.4, 564-570. THE CAMPI FLEGREI DEEP DRILLING PROJECT ‘CFDDP’: UNDERSTANDING THE MAGMA-WATER INTERACTION AT LARGE COLLAPSE CALDERAS G. De Natale, C. Troise, A. Troiano, M.G. Di Giuseppe, A. Sangianantoni, E. Vertechi, S. Carlino, R. Somma, Z. Petrillo INGV-Osservatorio Vesuviano, Naples, Italy Campi Flegrei caldera is a good example of the most explosive volcanism on the Earth, a poten- tial source of global catastrophes. Alike several similar volcanic areas (Yellowstone and Long Val- ley, USA; Santorini, Greece; Iwo Jima, Japan, etc.) its volcanic activity, i.e. eruptions and unrests, is dominated by physical mechanisms involving the strict interaction between shallow magma sources and geothermal systems. Furthermore, just like similar areas, it should be characterised by very large shallow magma chambers, filled by residual magma left after the ignimbritic caldera 170 GNGTS 2011 SESSIONE 1.3 forming eruptions. However, neither the physical mechanisms of magma-water interaction, nor the evidence for such large magma chamber, have been yet clear enough to be used for detailed vol- canological interpretation and eruption forecast. Campi Flegrei caldera, with respect to many simi- lar area, has the advantage that the most interesting structural details and main volcanic features appear located at shallower depth, making it a natural candidate for a deep drilling project aimed to understand the volcanic structure of calderas. The CFDDP project, sponsored by ICDP (Internation- al Continental Drilling Program), aims to understand, for the first time, the location and rehology of large residual magma chambers and the mechanisms of interaction between magma and aquifer systems to generate eruptions and unrests ay large collapse calderas. CFDDP is then structured as a large multidisciplinary project, with the main goal of volcanic risk understanding and mitigation, and a further goal to launch geothermal energy exploitation at this and other volcanic areas of Italy. A broader goal of the CFDDP project is to establish at Campi Flegrei, a densely urbanised area in a developed western country, a natural laboratory to study volcanic risk, environmental and tech- nology issues, geothermal energy exploitation. CFDDP is then a multi-purpose, multidisciplinary project involving cooperation of several inter- national Institutions. Because of its complexity and the involvement of drilling activities and logis- tic solutions, besides a reliable scientific planning it also required optimal solutions to several administrative and communication problems, generally out of the routine activities of a public research Institution. For these reason, new experience has been gained by the involved Institutions about administrative, normative and logistic solutions, which can be highly valuable for the Italian geophysical community to plan and manage future, large multi-disciplinary projects. ROLE OF HEAT ADVECTION IN A CHANNELLED LAVA FLOW WITH POWER LAW RHEOLOGY M. Filippucci1,2, A. Tallarico2,3, M. Dragoni4 1 INGV, Catania, Italy 2 CIRISIVU, University of Bari, Bari, Italy 3 Earth and Environmental Science Department, University of BarI, Italy 4 Department of Physics, University of Bologna, Italy In lava flows the mechanism of cooling and solidification plays a very important role in control- ling the flow dynamics. At the lava flow surface, for temperatures above 400 C, the heat flux due to thermal radiation is at least one order of magnitude greater than the heat flux due to the free con- vection in the atmosphere and conduction to the ground (Keszthelyi et al., 2003). This means that the cooling of a basaltic lava flow can be considered dominated by thermal radiation at least in the first hundreds of meters from the eruption vent (Neri, 1998). The effect of advective heat transport is often neglected. Keszthelyi and Denlinger (1996), studying the initial cooling of pahoehoe lava flow, which is totally covered by crust, neglected the effect of advection and explained this choice observing that advective heat, being the product of velocity and temperature gradient in the flow direction, should be zero everywhere. In fact, the lava is mostly isothermal and the temperature gradient is null. Neri (1998) neglects of advection as source of internal heat respect to crystallization in the solidification process. Ball et al. (2008), on the basis of surface temperature measurements of active pahoehoe flows, state that the advective heat transport is unimportant as long as the lava surface moves at the same velocity of the underly- ing layers but it becomes not negligible once the velocity of the crust is smaller than the velocity of the underlying lava. We examine the role of heat advection considering the cooling of a channelled gravity-driven lava flow. A numerical solution to the equation of motion governing the flow is given by Filippuc- ci et al. (2010). The temperature dependent pseudoplastic rheology is modeled using the experimen- tal results of Hobiger et al. (2011) for the basaltic melt of Sommata (Vulcano island, Italy). We assume that lava starts cooling as it exits from the vent with constant temperature. The heat loss at 171.