GNGTS 2013 - Atti del 32° Convegno Nazionale

Carlino S., Somma R., 2010, Eruptive versus non-eriptive behaviour of large calderas: the example of Campi Flegrei caldera (southernItaly), Bull Volcanol 72:871-886. doi:10.1007/s00445-010-0370-y. Chiodini G., Caliro S., De Martino P., Avino R., Gherardi F., 2012, Early signals of new volcanic unrest at Campi Flegrei caldera? Isights from geochemical data abd physical simulation, Geology, doi: 10.1130/G33251.1 De Natale G., Troise C., Pingue F., 2001, A mechanical fluid-dynamical model for ground movements at Campi Flegrei caldera. J Geodynam., 32, 487-517. Lipman P.W., 1997, Subsidence of ash-flow calderas: relation to caldera size and magma-chamber geometry, Bull. Volcanol., 59,198-218. Manning C.E., and Ingebritsen S.E., 1999, Permeability of the continental crust: Implications of geothermal data and metamorphic systems: Reviews of Geophysics, v. v. 37 pp. 127-150. Troiano A., Di Giuseppe M.G., Petrillo Z., Troise C., De Natale G., 2011, Ground deformation at calderas driven by fluid injection: modeling unrest episodes at Campi Flegrei (Italy). Geophys J. Int., 187:833-847. doi:10.111/j.1365- 246X.2011.05149.x Vanorio T., Virieux J., Capuano P., Russo G., 2005, Three-dimensional seismic tomography from P wave and S wave micro earthquake travel times and rock physics characterisation of the Campi Flegrei caldera. J Geophys Res 110:B03201. doi:10.1029/ 2004JB003102 Woo J.Y.L., and Kilburn C.R.J., 2010, Intrusion and deformation at Campi Flegrei, southern Italy: Sills, dikes and regional extension, J. Geophys. Res. doi: 10.1029/2009JB006913. Zollo A., Maercklin N., Vassallo M., Dello Iacono D., Virieux J., Gasparini P., 2008, Seismic reflections reveal a massive melt layer feeling Campi Flegrei caldera. Geophys Res Lett 35: L12306. doi:10.1029/2008GL034242 Continuous geochemical monitoring by mass-spectrometer in the Campi Flegrei geothermal area. An application at Pisciarelli-Solfatara (diffuse and fumarolic gases) A. Fedele 1 , R. Somma 1 , T. Wiersberg 2 , M.G. Di Giuseppe 1 , A. Troiano 1 , C. Troise 1 , G. De Natale 1 1 INGV-Osservatorio Vesuviano, Naples, Italy 2 Deutsches GeoForschungsZentrum GFZ, Potsdam, Germany Introduction. The Campi Flegrei (Southern Italy) is a restless, nested caldera structure resulting from two main collapses related to the two most powerful eruptions of the volcanic system (Orsi et al. , 1992, 1995, 1996.): the Campanian Ignimbrite CI. eruption 37 ka (Deino et al. , 1992, 1994; Armienti et al. , 1983; Rosi and Sbrana, 1987; Rosi et al. , 1983, 1996; Barberi et al. , 1991; Fisher et al. , 1993; Civetta et al. , 1997) and the Neapolitan Yellow Tuff (NYT) eruption 12 ka (Alessio et al. , 1971; Orsi and Scarpati, 1989; Orsi et al. , 1992, 1995, 1996). The structural boundaries of both CI and NYT calderas result from partial reactivation of earlier regional faults (Orsi et al. , 1996.). The central part of the younger NYT caldera is uplifting since its formation, likely as a consequence of the arrival of new magma in the system (Orsi et al. , 1996). The uplift occurs through a complex simple-shearing block resurgence mechanism (Orsi et al. , 1991). Because of this mechanism, the conditions for magmas to rise to the surface were established only in those parts of the caldera floor subject to extensional stress (Orsi et al. , 1996). Thus, the caldera structure strongly constrains the areal distribution of volcanism active during the past 12 ka. Volcanism in the Campi Flegrei began more than 60 ka ago and was essentially explosive and subordinately effusive (Orsi et al. , 1996; Pappalardo et al. , 1999). The sedimentological characteristics of deposits erupted before the CI eruption indicate that volcanism was highly explosive and that vents were located also outside the Campi Flegrei depression (Orsi et al. , 1996). The products erupted before the CI eruption range in composition from latite to phono-trachyte. The CI is the largest pyroclastic flow deposit of the Campanian area. The products range in composition from trachyte to phono-trachyte. They covered an area of 30,000 km 2 with an estimate volume of erupted magma of 150 km 3 DRE (Fisher et al. , 1993; Civetta et al. , 1997). After the Neapolitan Yellow Tuff eruption and related caldera collapse that occurred within the 39 ka-caldera, at least 70 eruptions, took place in three epochs of intense activity (15.0÷9.5, 8.6÷8.2 and 4.8÷3.8 ka) and followed one to another at mean time intervals of a few tens of 245 GNGTS 2013 S essione 1.3