Active tectonics in the Calabrian Arc: Insights from the Late Miocene to Recent structural evolution of the Squillace Basin (offshore eastern Calabria)

The Calabrian Arc represents one of the most active sectors of the upper plate of the Tyrrhenian-Ionian subduction system. This research aims to reconstruct the evolution of the Squillace Basin (Ionian offshore of the Calabrian Arc) from the Late Miocene to Recent times and recognise active shallow and deep structures using a multiscale approach. The latter is based on interpreting high-penetration and high-resolution seismic reflection profiles, calibrated with well-log data coupled with bathymetric data and the distribution of instrumental earthquakes. Data highlight three steps in the evolution of the Squillace Basin. A Late Miocene extensional event led to the formation of WNW-ESE orien…

Large deep-seated slump structure off Ischia volcanic island, Eastern Tyrrhenian sea (Italy)

Ischia island is located over the Campania sector of Eastern Tyrrhenian margin and represents the sub-aerial section of a larger, E-W trending volcanic ridge including others submerged or buried volcanic edifices. The island itself result from the coalescence of a multitude of small to medium scale eruptions leading to the emplacement of domes, lava flow and pyroclastic deposits and ignimbrites (VEZZOLI et al., 1988) ranging from alkali basalts to trachytes. The oldest basement dates back to 150 ky and crops out along the perimeter of the island especially to the south. Latest eruption occurred in 1302 A.D. and together with strong hydrothermal activity, ground uplift and seismic shaking in…

Geophysical investigations along the Tyrrhenian shore of Calabria

The Tyrrhenian Sea is a widely investigated basin developed in the Mediterranean area within the frame of Europe- Africa convergence and Ionian plate subduction process (Faccenna et al., 2014; Orecchio et al., 2014 and references therein). Since the Late Miocene, extension within the Tyrrhenian Sea was associated with coeval shortening in the Apennines-Maghrebide orogen and progressive southeastward rollback of the Ionian subducting plate. In this framework both extension and widespread volcanism well represented by the Vavilov and Marsili basins and the Aeolian volcanic arc, are typical features of the Tyrrhenian Sea region. Several authors (De Ritis et al., 2010; Loreto et al., 2015 and r…

The submerged structure and stratal architecture of the Neapolitan Yellow Tuff (NYT) caldera, offshore the Campi Flegrei, (Eastern Tyrrhenian Margin): New insights from high resolution seismics and gravity core data

The Campi Flegrei is an active volcanic area defined by a quasi-circular depression that covers some 200 km2 of the coastal zone of SW Italy, a large part of which develops off the Naples (Pozzuoli) Bay (Fig. 1). The area has been active at least since 60 ka BP ( Pappalardo et al., 1999), and is structurally dominated by a caldera, 6 km in diameter, associated with the eruption of the Neapolitan Yellow Tuff (NYT), a 40 km3 Dense Rock Equivalent (DRE) ignimbrite (Scarpati et al., 1993) dated at ca 15 ka BP (Deino et al., 2004), that covered the district now occupied by the city of Naples, the Campi Flegrei and a large area of the continental shelf off the Pozzuoli Bay. The volcanological evo…

Estensione e ciclicità di accumuli debritici tardo-pleistocenici nei bacini di Sibari e Corigliano (Mar Ionio): implicazioni per la tettonica recente ed attiva

Corpi sedimentari caratterizzati da facies sismica “trasparente” di notevole spessore (sino a 35 m) sono stati documentati in più livelli della copertura tardo-pleistocenica della Piana Abissale del Mar Ionio ed interpretati come megatorbiditi innescate da megatsunami. Il più recente di questi corpi è stato posto da Autori vari, in relazione ai collassi vulcanici del Santorini o dell’Etna o al sisma distruttivo di Creta del 365 d.C. [Polonia et al., 2013]. Corpi “trasparenti” di notevole spessore (15-30 m) e estensione (> di 100 km2), sono stati segnalati anche nel Mar Ionio nord-occidentale e interpretati come accumuli debritici tardo-pleistocenici-olocenici, presumibilmente sismoindotti […

Architecture of the NYT caldera and inner resurgent dome (Pozzuoli Bay, Campi Flegrei): new insights from seismic reflection and DInSAR data

The Campi Flegrei and its offshore prolongation (Pozzuoli Bay) are a volcanic area dominated by a collapse caldera associated with the Neapolitan Yellow Tuff (NYT) eruption, occurred at ~15 ka BP, and by an intra-caldera resurgent dome. We present new insights into: a) the geometry and kinematics of faults formed inside and at the edge of the caldera, b) the architecture of the caldera and the resurgent dome, and c) the relationship between the structural elements of the caldera and ground deformation. This work is based on the integration of single- and multi- channel seismic, swath bathymetry data and ground deformation maps. The main results highlight that the NYT caldera, offshore, is c…

Geodynamics and active tectonics of the Calabrian Arc: thecontribution of regional and local deformation sources.

Volcanism at Slab Tear Faults: the Diamante-Enotrio-Ovidio volcanic complex (offshore north-west Calabria)

Several arc-shape sectors form the central and southern part of the Italian peninsula, representing the emerged portion of the continental crust disjoined by slab tear faults (e.g., Olevano-Antrodoco, Ortona-Roccamonfina Tindari-Letojanni faults). These sectors are characterized by different drift velocities and tectonic patterns, while above to them important volcanic phases developed, such as the Vulture volcano (onshore) and the Vulcano-Lipari-Salina alignment (offshore). In the Tyrrhenian basin such kind of volcanism is still poorly investigated and understood though it could be revealed by low-resolution geophysical anomalies and volcanic seafloor morphologies. This is probably due to …

An Integrated Multiscale Method for the Characterisation of Active Faults in Offshore Areas. The Case of Sant’Eufemia Gulf (Offshore Calabria, Italy)

Diagnostic morphological features (e.g., rectilinear seafloor scarps) and lateral offsets of the Upper Quaternary deposits are used to infer active faults in offshore areas. Although they deform a significant seafloor region, the active faults are not necessarily capable of producing large earthquakes as they correspond to shallow structures formed in response to local stresses. We present a multiscale approach to reconstruct the structural pattern in offshore areas and distinguish between shallow, non-seismogenic, active faults, and deep blind faults, potentially associated with large seismic moment release. The approach is based on the interpretation of marine seismic reflection data and …

Plio-Quaternary tectono-stratigraphic evolution of the Paola fore-arc basin (western Calabria continental margin): Insight from high-resolution seismic reflection data

We reconstructed the most relevant geologic features across the Paola Basin (offshore western Calabria) and its Pliocene to Recent sedimentary and tectonic evolution using a grid of seismic profiles acquired within the frame of the EU-SINBUS project in the 1995. We used seismostratigraphic analysis to outline the seismic units. The Messinian horizon, as well as regional unconformities recognized in the Plio-Pleistocene geological record of the basins developed within or adjacent to the Calabrian Arc, played a key role to assign ages to the sedimentary units. We identified five seismic units on seismic lines, based on the internal configuration and seismic-stratigraphic character of reflecto…

HIGH-RESOLUTION SEISMIC SURVEY IN THE WESTERN CALABRIA AND EASTERN SICILY OFFSHORE: IMPLICATIONS WITH VERTICAL TECTONICS

High-resolution seismic data acquired along the continental shelf/upper slope offshore of Capo Vaticano (western Calabria), Milazzo Promontory and Mt. Etna (eastern Sicily) allow to provide new insights on vertical mobility related to active tectonics. A number of depositional sequences bounded by unconformities or correlative para-conformities were recognized on Sparker profiles in the first 200-300 m below the sea-floor. The most recent sequence overlays a widespread erosional surface that ostensibly formed during the sea level stillstand of the Last Glacial Maximum (LGM), whereas a stack of depositional sequences, which are interpreted as representing the falling and low-stand systems tr…

Long-term earthquake potential of active faults by using coastal and off-shore geological and morphological indicators

Seismogenic fault models and active deformation ones coupled with models of both earthquake rate and earthquake probability were recently used in a time-independent modelling. The integration of models allows to estimates the magnitude, location, and likelihood of potentially damaging earthquake ruptures in regions with high natural seismic hazard. Improvements of these models imply the recognition of the spatial geometry of the larger, active faults, deemed to be the source of the most damaging future earthquakes. However, identifying active faults and calculating their geologic slip rates for deriving earthquake rates are not easy tasks in regions inaccessible to direct field studies like…

Geodetic, geological and geophysical evidence of active tectonics in south-western Sicily and offshore

tIntegrated geological, geodetic and marine geophysical data provide evidence of active deformation insouth-western Sicily, in an area spatially coincident with the macroseismic zone of the destructive 1968Belice earthquake sequence. Even though the sequence represents the strongest seismic event recordedin Western Sicily in historical times, focal solutions provided by different authors are inconclusive onpossible faulting mechanism, which ranges from thrusting to transpression, and the seismogenic sourceis still undefined. Interferometric (DInSAR) observations reveal a differential ground motion on a SW–NEalignment between Campobello di Mazara and Castelvetrano (CCA), located just west of…

Caratteristiche sismostratigrafiche di strutture sedimentarie diagnostiche di correnti di fondo nell'off-shore del Golfo di Taranto

L’analisi integrata di dati multibeam e sismici ad altissima risoluzione (Chirp Sub-Bottom), acquisiti in un settore del Golfo di Taranto (Mare Ionio), ha permesso di identificare e classificare strutture sedimentarie diagnostiche di correnti di fondo (conturiti), formatesi nel tardo Quaternario. La classificazione proposta è basata sia su criteri sismo-stratigrafici che sulla comparazione con strutture analoge documentate da precedenti autori nei bacini oceanici [Faugeres et al., 1999 con rif.]. Nell’area in esame sono stati identificati quattro settori (Alto dell’Amendolara, Bacino di Corigliano, Bacino dell’Amendolara ed Alto di Rossano-Cariati) caratterizzati da morfologia, pendenza e p…

Volcaniclastic Deposition and migration of basin depocentres after the eruption of the Neapolitan Yellow Tuff: The Pozzuoli Bay (Naples, Italy)

The Campi Flegrei is an active caldera located on the coastal zone of SW Italy (Fig. 1), close to the town of Naples Bay, that has been characterized by explosive activity and unrest throughout the Late Quaternary. This area represents a very active segment of the Eastern Tyrrhenian margin and may be regarded as an ideal laboratory to understand the mechanisms of caldera dynamics and the interplay between volcanism, tectonics and sedimentary processes along a continental back-arc margin. Recent research at Campi Flegrei has shown that a significant part of the offshore volcaniclastic products and structures, the late-stage geodynamic evolution of the inner caldera resurgence and the stratal…

Active volcano-tectonic deformations: a 3D seismic reflection experiment in the resurgent dome of the NYT Caldera (Pozzuoli Bay, Campi Flegrei, Naples)

An ultra-resolution, 3D seismic reflection data cube was collected during an oceanographic cruise organized in the frame of a joint project involving Italian research institutions, the University of Palermo, Catania and Napoli, CNR of Napoli and INGV Roma, and two companies, the Geo Marine Survey System (The Netherlands) and GeoSurvey (Portugal). The data acquisition approach charted during this cooperation was based on innovative technologies for the offshore imaging of stratigraphy and structures at continental margins with horizontal and vertical resolution at decimetric scale. In this work, we present the methodology used for the 3D HR-seismic reflection data acquisition and the prelimi…

From land to sea: multi-scale and multi-resolution analysis of active deformation and seismogenic sources around the coasts of Southern Italy

During the last decade, we have blended our individual skills to form a research group devoted to investigating active crustal deformation in areas adjacent to the coast of Southern Italy, with the aim to bridge the gap between the onshore and offshore realms. Our research is based on a multi-scale and multi-resolution approach that includes high-resolution seismics, coastal morpho-tectonics and structural geology, complemented by seismicity, Global Positioning System and InSAR. Need and opportunities of such an endeavor arise from the basic observation that, although most population centers lie close to the coastal areas, very little is known about active structures at the sea. However, hi…

Perforazione della Caldera dei Campi Flegrei - Una proposta anfibia IODP-ICDP

Active calderas are major volcanic features of the Earth’s crust associated with shallow magma reservoirs, high geothermal gradients, and geodynamic unrests often documented through historical time. As large caldera-forming eruptions are also among the most catastrophic events that may affect the Earth’s surface, calderas are ostensibly the sites of major interest for both the scientific community and governmental institutions worldwide. The Campi Flegrei is an active volcanic area located west of the city of Naples, largely on the continental shelf of the Eastern Tyrrhenian margin that has been characterized by dominantly explosive eruptions during the latest Quaternary. This is one among …