Structural setting of the Bay of Naples (Italy) seismic reflection data: implications for Campanian volcanism Pier Paolo G. Bruno a, * , Antonio Rapolla b , Vincenzo Di Fiore a a Osservatorio Vesuviano, Via Diocleziano, 328, 80124 Naples, Italy b Dip. Scienze della Terra, Universita ` Federico II, L.go S. Marcellino, 10, 80138 Naples, Italy Received 14 August 2002; accepted 14 July 2003 Abstract This paper focuses on the recent tectonic evolution of the Bay of Naples with the aim of exploring the connection between local tectonics and volcanism. We reprocessed the seismic reflection dataset acquired in the area in the late 1973. The new processing was highly successful in obtaining a decisive strong reduction of random noise, removal of coherent noise and reduction of spatial aliasing. Classical interpretative schemes and complex attributes of seismic traces were used to reconstruct fault kinematics and reflector patterns. The results show that the faults affecting the Bay of Naples exhibit prevailing NE structural strikes, with the exception of the Pozzuoli Caldera where NW patterns are also common. Many faults are subvertical and show seismic evidence of volcanic activity along them. A main alignment of conjugate NE – SW faults, named here as ‘‘Magnaghi–Sebeto line’’, intersects several submarine volcanic banks and separates the bay into two sectors, characterized by important geological, geophysical and petrochemical differences. The structural configuration of the bay may reflect the occurrence of either oblique extension or a transfer zone of the NW – SE fault system, along which, in the Campanian – Lucanian Apennine chain, great vertical displacements occur. D 2003 Elsevier B.V. All rights reserved. Keywords: Marine geophysics; Seismic reflection; Volcanism; Bay of Naples; Tyrrhenian Sea 1. Introduction In the Bay of Naples, the presence of volcanoes with geological and historical records of very explo- sive events (such as ignimbrites and Plinian eruptions) on a densely populated territory implies a high risk. The recent tectonic evolution of the bay and the links between tectonics and volcanism, crucial to assess the risk, are, unfortunately, still subjects of debates. This is mainly due to the difficulty of giving univocal interpretations to the insufficient mesh of geological and geophysical data in the area. The available air- borne potential field data (Agip, 1981) lack spatial resolution. More recent gravity and magnetic acqui- sition only concerned limited sectors of the bay. Among the geophysical data, active seismic data and, in particular, seismic reflection data are crucial because they hold the highest resolution. A recently completed EU-funded project, based on acquisition of global-offset active seismic data, has established the 3D subsurface structure below Mt. Vesuvius area (e.g. Zollo et al., 2002). One of the main outcomes of this 0040-1951/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0040-1951(03)00327-5 * Corresponding author. Tel.: +39-81-6108437; fax: +39-81- 6100811. E-mail address: bruno@ov.ingv.it (P.P.G. Bruno). www.elsevier.com/locate/tecto Tectonophysics 372 (2003) 193– 213