GNGTS 2021 - Atti del 39° Convegno Nazionale

113 GNGTS 2021 S essione 1.2 several fumaroles close to Via Antiniana (Fig. 2). In order to study the interaction between upstream-flowing hydrothermal fluid and structures, we present the results of structural and electrical resistivity tomography (ERT) surveys. The latter technique has been selected as sensi- tive to the presence of fluids and their circulation and as useful tool to detect and characterize structures in the subsurface. Geological Setting The Campi Flegrei caldera is an active volcanic field including the western part of the city of Naples. The early volcanic history of Campi Flegrei was characterized by the occurrence of a very large eruption, known as Campanian Ignimbrite, that took place ca. 40 ka and formed a caldera of ca. 12 km in diameter (Giaccio et al., 2017). After this eruption, some significant events occur, among which the more energetic was the Neapolitan Yellow Tuff (NYT) eruption (15 ka; Deino et al., 2004) that produced a nested caldera characterized by tangential and concentric ring faults with dominant normal kinematics (Vitale & Isaia, 2014). The last 15 ka were characterized by ca. 70 eruptions (Bevilacqua et al., 2015; Di Vito et al., 1999; Isaia et al., 2009; Orsi et al., 2004; Smith et al., 2011), classified in 3 epochs divided by 2 period of calm, localized in the NYT caldera. The most recent volcanism (4.3-3.5 ka; Epoch 3B; Smith et al., 2011) was characterized by the Plinian Agnano-Monte Spina eruption (4.55 ka; de Vita et al., 1999; Smith et al., 2011) that produced a minor caldera (3 km in diameter) named Agnano Plain (Fig. 1). This collapsed is area surrounded by a segmented rim bounded by ring faults (Fig. 1) along which the following erupti- ve episodes has occurred. Volcanism resumed with a cluster of small volcanic edifices within and Fig. 2 - Geological map of the Solfatara-Pisciarelli area and schematic stratigraphic log (modified after Isaia et al., 2021).