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Seismic stratigraphic analysis of very high-resolution single channel reflection seismic profiles provided insights into the last ~10 ka vertical deformation pattern in the submerged part of the Campi Flegrei resurgent caldera, off the Pozzuoli Bay. The collapse of the central part of the Campi Flegrei is associated with the eruption of the Neapolitan Yellow Tuff (NYT) at ~15 ka BP, and was followed by discrete phases of intracaldera volcanic activity and resurgence (Di Vito et al., 1999). Only in recent years the southern part of the caldera, presently submerged off the Pozzuoli Bay, has been explored using marine geophysical data (Sacchi et al., 2014; Steinmann et al., 2016). Interpretation of the high-resolution seismic reflection dataset acquired during the Cruise SEISTEC_2013, calibrated by marine gravity cores, allowed us to identify key horizons between the 1538 AD M. Nuovo and the ~3.7 ka Averno eruptions. Chronostratigraphy of the older part of the caldera fill was inferred through tentative correlation with significant eruptions known onland. Seismic stratigraphic interpretation reveals the occurrence during the last ~10 ka of at least three generations of Prograding Wedges (PW1-PW3) that were likely associated with corresponding periods of relative sea-level stands, and of minor coastal terraces. Correction of the observed depth of each sea-level indicator for the paleobathymetric estimate and for the glacio-hydro-isostatic sea-level change occurred since its formation, allowed to reconstruct differential relative sea-level curves for the western, central and eastern sector of the submerged part of the caldera. Preliminary results indicate that the periods of relative sea-level and accommodation space stability that allowed the onset of Prograding Wedges were attained when uplift occurred at a rate comparable to the rate of sea-level rise. These periods ostensibly correspond to known different phases of volcanic activity and unrest, suggesting that not only volcanism but also ground deformation were temporally clustered. Subsidence prevailed during periods of volcanic quiescence.

Most of the world’s floodplains are affected by subsidence, a phenomenon that includes, among others, the salinization of the aquifer, coastal erosion, greater vulnerability to flooding and storm surges, structural damage to infrastructure. In the Mediterranean, numerous floodplain plains are affected by subsidence due to both the rise in global sea level and other natural and anthropogenic factors. In analyzing the potential drivers of subsidence, in recent times the sedimentological evolution of modern river deltas has been considered, which began to form around 6500 years, after the fall of sea level in the last glacial phase (Last Glacial Maximum - LGM) and the subsequent aggradation and Holocene progradation. The Incised Valleys (IV) formed during the LGM were filled by fluvial-lacustrine, transitional and marine deposits, characterized by sands, silts, clays and peat. Recent studies confirm that natural compaction can cause a decrease of several millimeters for years, especially in coastal deposits rich in organic substances. The aim of the present study is to define the stratigraphic architecture of the Holocene and the correlation with the ground deformation trends referring to two decades (1992-2010), which characterize the coastal alluvial plain of the Volturno River, in northern Campania. Assessment of subsidence trends was previously based on SAR (Synthetic Aperture Radar) interferometry techniques. The reconstruction of the satellite time series shows a general tendency to the ground subsidence over time of the whole area and a strong negative subsidence in three sites between the coast and the lower valley of the Volturno. The reconstructed stratigraphic architecture has shown that the unit which is the first substrate for Holocene and Recent sedimentation is represented by the Campania Grey Tuff (CGT), produced by the explosive volcanic activity of the Phlegrean Field about 39 ky and deposited over the whole Campana Plain. The CGT was deeply eroded by the fluvial activity during the LGM and the resulting Incised Valley was subsequently filled by fluvial-lacustrine, transitional and coastal deposits. The spatial intersection of the deformation data with the geological data showed a net overlap of the subsiding areas with the paleovalley contour. Furthermore, higher subsidence rates affect areas characterized by thicker Holocene sedimentary sequences and in particular where silt, clayey silt, clay and peat are the main lithologies. The latter,from a geotechnical point of view, are classified as fine grained soils with poor mechanical properties (high compressibility and low resistance). Furthermore, the inclusion of a significant amount of peat and organic matter is reflected in high values of secondary consolidation coefficient. This suggests that if anthropic activities can be the cause of a generalized process of primary consolidation, a key role is played by sthe tratigraphic structure and in particular by distribution and thickness of Holocene deposits, whose characteristics are at the origin of secondary consolidation and of the variability observed among subsidence rates. The results of this study confirm the importance of an integrated study for the assessment of hazards to coastal areas.

Resurgent calderas are among the largest and most dynamic volcanic structures on earth. They are typically associated with major eruptions with considerable volumes of pyroclastic deposits accompanied by large collapse structures and late stage deformation and uplift of the intra-caldera floor region. The Campi Flegrei is a vast volcanic area located on the coastal zone of the Campania region of SW Italy, a large part of which develops off the Naples (Pozzuoli) Bay. The area has been active since at least ~80 ka BP and is structurally dominated by a caldera collapse, ca. 8 km in diameter, associated with the eruption of the Neapolitan Yellow Tuff (NYT), a 30–50 km3 Dense Rock Equivalent ignimbrite dated at ca. 15 ka BP. In the past decades the shallow crustal structure of the NYT caldera has been mostly reconstructed using gravimetric and magnetic data, seismic tomography images and modelling (analogue) experiments, whereas, the structural elements of the caldera collapse in the Pozzuoli Bay have been largely inferred, based on seafloor morphology and associated deposits. Despite the conspicuous research so far conducted off the Campi Flegrei, the stratigraphic architecture of the NYT caldera structure and inner caldera deposits is still poorly understood. This is mostly because of the intrinsic limitations due to the insufficient resolution of previous seismic datasets, as well as to the lack of reliable geologic calibration of the offshore geophysical data. In this study we present a detailed structural and stratigraphic reconstruction of the submerged part of the NYT caldera obtained by full integration of swath bathymetry, high-resolution multichannel and single channel reflection seismics, gravity core, geochemical analysis of marine fluid vents and seafloor temperature profiling, recently acquired from the Pozzuoli Bay, along with existing geological, geophysical and geodetic datasets on land. Particularly, the high-resolution reflection seismic data offer unprecedented detailed insights into the stratigraphy and shallow structure of the NYT caldera collapse–ring fault zone–inner resurgence system. The results of this research provide a contribution to the understanding of structural style and timing of deformation of restless, resurgent calderas that develop along active continental margins.

This book presents current research in the field of geophysics, particularly referring to some principles, applications and emerging Technologies. Topics discussed comprehend environmental geophysics, with an explanation of geophysical methods (Seismic Refraction and Reflection Techniques, Seismic Analysis of Surface Waves, Electrical Methods, Gravimetric and Microgravimetric Methods, Magnetic and Electromagnetic Methods) and new methodologies of processing and interpretation with examples in the area of Greece; application of innovative geophysical techniques in coastal areas, showing a new approach to seismic data acquisition in the backshore-foreshore area, joining up land and marine seismic data through a marine streamer connected to a land cable with examples in Procida and Ventotene islands (Southern Italy); marine geophysics of the Naples Bay focusing on seismic and magnetic data offshore the Vesuvius, Phlegrean Fields, Ischia and Procida volcanic complexes and on technological evolution in seismic data acquisition from explosive, Sparker and Watergun seismic sources towards new techniques including MEAS (Multispot Extended Array Sparker) used in marine geological mapping of Southern Italy continental shelf and slope; oceanographic aspects regarding the oceanic oscillation phenomena and their relationships with the synchronization and stochastic resonance, particularly referring to the transitions among stable and unstable states of western boundary currents, such as the Kuroshio in Japan; oceanographic aspects regarding the assessment of ocean variability in the Sicily Channel (Southern Italy) through a numerical 3D model based on Empirical Orthogonal Functions (EOF) analysis aimed at studying the seasonal and interannual variability of the oceanographic circulation and hydrology and extending down to the African coast; experimental application of distributed optical fiber sensors through Brillouin Optical Time Domain Analysis (BOTDA) to the monitoring of artificially induced crack opening in the volcanic rocky slope of Coroglio coastal cliff (Naples town, Southern Italy) aimed at the development of early warning systems and geomorphologic setting of coastal cliffs, characterized by rock falls, topples and slides.

An integrated marine geophysics and satellite remote sensing study of Naples Bay (Italy) has been carried out to evaluate the presence, magnitude, areal extent and activity of the Naples Active Deformation Line (NADEL), a structural bend affecting the post Last Glacial Maximum (LGM) sedimentary sequences. Sparker high-resolution mono-channel profiles and multibeam swath bathymetric data were acquired during the SAFE-2014 research cruise, carried out on board of the Urania R/V of CNR on August 2014. The marine geophysical study was integrated with the ground deformation field of the emerged sectors of the study area (Sorrento Peninsula and Campi Flegrei), derived by Synthetic Aperture Radar interferometry (InSAR) data, referred to the 1993-2000 and 2003-2010 time periods. The InSAR data obtained from the ERS, RADARSAT and ENVISAT images were processed with the method of Permanent Scatterers (PS). Marine geophysical data provide evidence of morphological and stratigraphic features extending for about 18 km along a N130E strike. The NADEL deformation bend divides a NE offshore area, characterized by a flat morphology (slope< 1°, on average) from a SW sector, where the slope at >180 m below the sea level is, on average, 1.5°). In the area located SW of NADEL, the slopes are morphologically characterized by the presence of the uppermost active branches of the Magnaghi canyon, which are bounded upward by the presence of the NADEL pattern. Thus, we suppose that the emplacement of the Magnaghi branches and NADEL are linked. InSAR data show that a similar deformation pattern can be detected also inland, in the distal sectors located NW and SE from the NADEL edges. The NADEL segments also affect the distal SW sector of the Campi Flegrei active caldera and the carbonate units cropping out in the Sorrento Peninsula, thus extending in length for more than 40 km.

Monitoring Test of Crack Opening in Volcanic Tuff (Coroglio Cliff, Italy) Using Distributed Optical Fiber Sensor

The southern Apennine is the segment of the circum-Mediterranean orogenic system between the central Apennine to the North and the Calabria-Peloritani arc to the South, bounded by the Ortona-Roccamonfina and the Sangineto tectonic lines respectively. It consists in a salient: north-east verging thrust and fold belt, interposed between the back-arc Tyrrhenian basin to the West and the undeformed Apulian-Adriatic foreland to the East. Its present Structural setting is the result both of mainly compressive tectonic events, related to the subduction followed by the roll-back of the Adria plate, and of the extensional tectonics related to the opening, since the late Miocene, of the Tyrrhenian sea (MALINVERNO & RYAN, 1986; PATACCA & SCANDONE, 1989; DOGLIONI, 1991). Aiming to Point Out the space-time migration of the deformation, a geological map of the area between the Ortona-Roccamonfina tectonic line to the North and the Maratea-Val d'Agri alignment to the South showing the possible kinematic units of the southern Apennine has been elaborated. The above area includes the whole Campania and part, of Lucania, Molise and Puglia regions. A kinematic unit can be defined as a stack of tectonic units (or even only one), eventually covered with thrust top deposits, that piled Lip during the same tectonic event and afterwards behaved like an unique geological body in respect to more external areas. In the frame of the regional geological setting, some well established sedimentologic and stratigraphic characteristics have been assumed as reference criteria for grouping together some tectonic units in a kinematic unit: (i) the beginning and the gradual increase Lip to prevail of the immature siliciclastic sedimentation marks the depocentral phase in the evolution of a foredeep basin; (ii) the foredeep deposits rest conformably on the older successions, as the angular unconformity due to the progressive flexuration of the foreland is not appreciable at a local scale; (iii) the compressive tectonic event, immediately following the foredeep stage, involves a wide portion of the flexured foreland, that is accreted to the nappe stack of the chain. In each tectonic unit this tectonic event is chronologically constrained between the age of its conformable foredeep deposits and by the age of the Unconformable thrust-top deposits sealing the contacts among different tectonic units. However this simple relationships may be masked by later compressive and extensional tectonic events, as well as by transcurrent tectonics. The possible presence Of younger deposits resting unconformable on the already deformed substratum and related thrust top deposits is a constraint to the age of these later tectonic events. The map has been elaborated tacking into account, besides the numerous and sometimes contrasting data of the literature, even data, often still unpublished, from the surveying of the new geologic map of Italy 1:50.000. The kinematic units, marked with capital letters (A to G from the older to the younger) group together tectonic units, derived from paleogeographic domains that have been affected by the first tectogenetic event in the same chronological interval. In each kinematic unit with lower case have been distinguished: a) the pre-orogenic succession; b) the foredeep stage deposits; c, d) the thrust-top basin deposits. The kinematic unit A includes several tectonic units (Liguride and Sicilide Complexes Auct.), mostly ocean derived, piled up to form accretionary wedge during the Early Miocene, following the closure of an oceanic branch (Lucanian Ocean) of the Neothetys realm. It is subdivided into: a) Jurassic to Aquitanian pre-orogenic successions (the ophiolite basement of some of them crops only SE of the mapped area); b) the Aquitanian-Burdigalian foredeep deposits; c) the upper Burdigalian/Langhian - Serravallian thrust-top deposits (Cilento Group, AMORE et alii, 1988; BONARDI et alii, 1988b; AMORE et alii, 2005); d) the Tortonian further thrust-top deposits. The kinematic unit B groups the units of the chain involved by the orogenic transport during the Serravallian-lower Tortonian. It is formed by: a) the upper Triassic-lower Miocene pre-orogenic successions, of the M. Bulgheria (SCANDONE et alii, 1964) and Alburno-Cervati Units (SCANDONE, 1972; BONARDI et alii, 1988a); b) the Langhian foredeep deposits; c) the middle-upper Tortonian thrust-top deposits. The kinematic unit C groups the units of the chain involved by the orogenic transport during the lower-middle Tortonian; in particular they are distinguished in: a) the upper Trias-Langhian pre-orogenic successions, forming the Picentini-Penisola sorrentina, Taburno-M. Marzano-Monti della Maddalena and the Capri-M. Monna-M. Foraporta Units (BONARDI (11 alii, 1988a; SGROSSO, 1998); b) the Serravallian foredeep deposits; c) the middle-upper (?) Tortonian thrust-top deposits. The kinematic unit D groups the units of the chain involved by the orogenic transport during the middle-uper Tortonian; in particular they are distinguished in: a) the lower Triassic-Langhian pre-orogenic succession belonging to Lagonegro II-Frigento Unit (SCANDONE, 1967, 1972; DI NOCERA et alii, 2002) and to Monte Croce Unit (SCANDONE & SGROSSO, 1974) and that upper Triassic-Cretaceous of the "Lagonegro I" Unit (SCANDONE, 1967, 1972); b) the Serravallian-lower Tortonian foredeep deposits; c) the Upper Tortonian thrust-top deposits; d) the upper Tortonian-lower Messinian further thrust-top deposits. The kinematic unit E groups the units of the chain involved by the orogenic transport between the upper Tortonian and the lower Messinian; in particular in this unit are distinguished: a) the Trias-middle Tortonian pre-orogenic successions referred to the Matese-M, Maggiore-M. Camposauro Unit (BONARDI e; alii, 1988a; SGROSSO, 1998); b) the middle-upper Tortonian foredeep deposits; C) the lower Messinian thrust-top deposits; d) the Upper Messinian further thrust-top deposits. The kinematic unit F groups the units of the chain involved by the orogenic transport during the upper Messinian; in this unit are distinguished: a) the Lias-lower Messinian pre-orogenic successions of the north-western Matese Unit (SGROSSO, 1996, 1998), the Frosolone Unit (SELLI, 1957) and the Daunia Unit (DAZZARO et alii, 1988); b) the Messinian foredeep deposits; C) the upper Messinian -lowermost Pliocene thrust-top deposits. The kinematic unit G groups the units of the chain involved by the orogenic transport during the upper? part of the lower Pliocene; in this unit are distinguished: a) the Tortonian-Messinian pre-orogenic successions of the Vallone del Toro Unit (BASSO et alii, 2002); foredeep deposits are not recognizable; c) thrust-top deposits of the upper part of the lower Pliocene; d) the middle-upper Pliocene further thrust-top deposits. In several tectonic units, elements useful to establish the age of the first deformation, i.e. the foredeep siliciclastic deposits or the immediately following Unconformable deposits, are missing, therefore their inclusion in one or another of the kinematic units is matter of debate. Also in this case the geometrical position and the regional framework can be used to formulate reliable hypotheses. The map is aimed to focalize the main open problems and stimulate the discussion about them. The analysis of the areal distribution of the kinematic units leads to some general considerations. On a small scale an irregular spatial distribution of the kinematic units is recognized. In the segment of chain represented by the map, the more internal tectonic units widely outcrop in the south-eastern sector and are missing northward even on the Tyrrhenian side. On the contrary the more external units, crop out only in the north-western sector, whereas in the south-eastern one they have not been recognized even by sub-surface data. This irregularity could be linked to original paleogeographic irregularities or even be the result of Plio-Pleistocene second order archings and of transcurrent faults that cut transversally the chain, but geodynamic causes still not clarified cannot be excluded. The elaboration of a kinematic map is an essential but not sufficient step for the palaeogeographic reconstructions that need further data and informations on the distribution of the units at depth. The difficulty in the palaeogeografic reconstructions is also due to the fact that the chain is at present constituted only by a few and unevenly distriuted fragments of the original domains.

This brief report discusses a key aspect of seismic risk, i.e., the underestimation of site amplification effects in many Italian urbanized areas that are located in alluvial plains or valleys and the related problem of computing the seismic hazard of a site from an accurate and thorough knowledge of local geologic and geoseismic factors.

con carta Geologica in scala 1:60000.