New insights on morpho-structures and seismic stratigraphy along the Campania continental margin (Southern Italy) based on deep multichannel seismic profiles

New insights on the deep regional geological structure of the Naples Bay are herein proposed through the constraints of seismic interpretation. Regional geoseismic sections along the Ischia-Capri-Volturno alignment of the Campania continental margin have been constructed. Main regional morpho-structures are: the Banco di Fuori, a morpho-structure high of the Meso-Cenozoic carbonates, bounding southwards the Naples Bay; the Dohrn canyon, separating the eastern side of the Bay, where sedimentary seismic sequences crop out, from the western one, where volcanic seismic units prevail; the Capri structural high, a sedimentary high related to regional uplift of Meso-Cenozoic carbonates along the Capri-Sorrento alignment; the Magnaghi canyon, eroding the Mg volcanic seismic unit southwards of the Procida island; the Capri Basin, a deep basin located south of the Naples Bay, filled by Pleistocene-Holocene sediments overlying Meso-Cenozoic carbonatic unit; the Salerno Valley, a half-graben filled by three seismic units corresponding to Quaternary marine deposits, overlying chaotic sequences related to the "Flysch del Cilento" Auct.; the Volturno Basin, filled by four marine to deltaic seismic sequences, frequently alternating with volcanoclastic levels, overlying deep seismic units, correlated with Miocene flysch deposits (sands and shales) and Meso-Cenozoic carbonates. On the Naples slope between the Dohrn and Magnaghi canyons a large volcanic edifice, only magnetically known, deeply buried under Quaternary volcanites and genetically related to the Procida volcanic complex has been modelled through seismic interpretation

Seismic images and rock properties of the very shallow structure of Campi Flegrei caldera (southern Italy)

In September 2001, an extensive active-seismic investigation (Serapis experiment) was carried out in the Gulfs of Naples and Pozzuoli, with the aim of investigating and reconstructing the shallow crustal structure of the Campi Flegrei caldera, and possibly identifying its feeding system at depth. The present study provides a joint analysis of the very shallow seismic reflection data and tomographic images based on the Serapis dataset. This is achieved by reflection seismic sections obtained by the 3D data gathering and through refined P-velocity images of the shallowest layer of Pozzuoli Gulf (z3,500 m/s) correlates with units made up of agglomerate tuffs and interbedded lava, which form the southern edge of the caldera, which was probably formed following the two large ignimbritic eruptions that marked the evolutionary history of the area under study. The upper part of the anomaly that tends to split into two parallel arcs is correlated with dikes, volcanic mounds and hydrothermal alteration zones noted in previous shallow reflection seismic analyses. The depth of the transition between the upper and lower parts of the anomaly is characterized by an abrupt Vp increase on the one-dimensional (1D) profiles extracted from the 3D tomographic model and by the presence of a strong reflector located at about 0.6/0.7 s Two Way Time (TWT) on Common Mid Point gathers. The move-out velocity analysis and stack of the P–P and P–S reflections at the layer bottom allowed to estimate relatively high Vp/Vs values (3.7±0.9). This hypothesis has been tested by a theoretical rock physical modeling of the Vp/Vs ratio as a function of porosity suggesting that the shallow layer is likely formed by incoherent, water saturated, volcanic and marine sediments that filled Pozzuoli Bay during the post-caldera activity.Published275-2841.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveJCR Journalreserve