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 evolution of the NYT caldera as been long described on the basis of outcrop and subsurface studies onland (Rosi & Sbrana, 1987; Orsi et al., 1996, 2004 and references therein; Di Vito et al., 1999; Perrotta et al., 2006; Fedele et al., 2011), but its offshore morphology, detailed structure and recent stratigraphic setting are still poorly understood. In this study we integrate geological and geophysical data of different resolution/penetration obtained from high-resolution reflection seismic profiles (Sparker and Chirp source) with gravity core and swath bathymetry to better constrain the shallow structure, stratigraphic architecture and latest Quaternary to Holocene evolution of the submerged sector of the NYT caldera off the Pozzuoli Bay. Our data clearly image, for the first time, the offshore geometry of the NYT caldera ring-fault zone, as well as the style and timing of volcano-tectonic deformation associated with the late stage evolution of the NYT inner caldera resurgence. Our interpretation suggests that since 15 ka the offshore sector of NYT inner caldera underwent significant deformation and uplift (with minor subsidence episodes) that occurred at almost the same rate as the post-glacial sea-level rise. Particularly, the inner Pozzuoli Bay started to deform soon after 15 ka BP, when sea-level rise was initially faster than uplift. This caused a general increase of the accommodation space that was progressively filled up by volcaniclastic sediments. Since ca. 8 ka BP, along with the mid Holocene decrease in the rate of the sea-level rise, the early NYT resurgent structure was then uplifted up to the sea-level or even to partial subaerial exposure. From ca. 8 to 5 ka BP two distinct layers of volcaniclastic resediments, mostly represented by gravity flow deposits, formed throughout the Bay. A significant post- Roman (post 2 ka BP) subsidence phase of ca 10 m is then recorded offshore Pozzuoli by the drowning of the infralittoral prograding wedge below the present-day fair-weather wave base. REFERENCES Deino AL, Orsi G, de Vita S, Piochi M (2004) The age of the Neapolitan Yellow Tuff caldera-forming eruption (Campi Flegrei caldera—Italy) assessed by 40Ar/39Ar dating method. J. Volcanol. Geotherm. Res. 133, 157–170. Di Vito M., Isaia R., Orsi G., Southon J., de Vita S., D’Antonio M., Pappalardo L., Piochi M., 1999. Volcanism and deformation since 12,000 years at the Campi Flegrei caldera (Italy), J. Volcanol. Geotherm. Res. 91 (2-4), 221-246. Fedele L., Insinga D.D., Calvert A.T., Morra V., Perrotta A., Scarpati C., 2011. 40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity. Bull. Volcanol. 73, 1323-1336. Orsi G, de Vita S, Di Vito M, 1996. The restless, resurgent Campi Flegrei nested caldera (Italy): constraints on its evolution and configuration. J. Volcanol. Geotherm. Res. 74, 179–214. Orsi G., Di Vito M.A. Isaia R., 2004. Volcanic hazard assessment at the restless Campi Flegrei caldera. Bull. Volcanol. 66, 514–530. Pappalardo L., Civetta L., D’Antonio M., Deino A., Di Vito M., Orsi G., Carandente A., de Vita S., Isaia R. & Piochi M., 1999. Chemical and Srisotopical evolution of the Phlegrean magmatic system before the Campanian Ignimbrite and the Neapolitan Yellow Tuff eruptions J. Volcanol. Geotherm. Res. 91, 141-166. Perrotta A., Scarpati C., Luongo G., Morra V., 2006. The Campi Flegrei caldera boundary in the city of Naples. In: De Vivo B (ed) Volcanism in the Campania Plain: Vesuvius, Campi Flegrei and Ignimbrites. Elsevier, Amsterdam, pp 85–96 (in the series Developments in Volcanology, 9) Scarpati C., Cole P., & Perrotta A., 1993. The Neapolitan Yellow Tuff- A large volume multiphase eruption from Campi Flegrei, Southern Italy. Bull. Volcan. 55, 343-35

The use of documentary sources for reconstructing flood chronologies on the Amalfi rocky coast (southern Italy)

Documentary source materials are essential for retrospective reconstruction of flood events occurring in past centuries. This paper presents methods of research and archiving of historical data from the 16th century to the present. The quality and completeness of the various original sources were evaluated and carefully analysed in their historical context, to avoid serious mistakes. Systematic investigation of about 3000 documents, mainly found in national State Archives and libraries, allows us to identify and localize at least 106 flood events occurring along the Amalfi coast (southern Italy) for five centuries between the years 1500 and 2000. The collected data provide useful details on flood dynamics, size of flooded areas, flood duration, damage level, number of victims and induced geological effects. When available in sufficient quantity, the flood data allow determination of very useful parameters such as the severity class, to identify large floods and their recurrence interval

Architettura stratigrafica ed evoluzione del Golfo di Pozzuoli negli ultimi 15 ka:una nuova prospettiva sulla caldera del Tufo Giallo Napoletano,Campi Flegrei, margine tirrenico orientale.

I Campi Flegrei rappresentano un distretto vulcanico attivo che si sviluppa al confine tra il settore emerso e sommerso del margine continentale campano. Il distretto vulcanico occupa una superficie di circa 200 km2, è strutturalmente dominato da una caldera di collasso del diametro di circa 8 km formatasi in seguito all’eruzione del Tufo Giallo Napoletano (TGN), un deposito ignimbritico del volume di 30-50 km3 Dense Rock Equivalent, datato a 15 ka B.P. circa, ed è attivo da almeno 78 ka B.P circa. L’obiettivo di questo lavoro è di ricostruire l’architettura stratigrafica e l’evoluzione vulcanotettonica tardo-Quaternaria del sistema caldera di collasso - faglia anulare - risorgenza intra-calderica del settore sommerso della caldera del TGN. A tal fine è stata analizzata una fitta maglia di profili sismici a riflessione monocanale di alta (Sparker) ed altissima (Subbottom Chirp) risoluzione. I dati sismici sono stati successivamente integrati sia con quelli ottenuti dall’analisi di carotaggi a gravità e batimetrici multibeam che con quelli disponibili in letteratura e, nell’insieme, analizzati in ambiente GIS. I nuovi dati indicano che il settore interno dell’area collassata a seguito dell’eruzione del TGN evolve inizialmente in condizioni di mare basso. L’area intra-calderica viene successivamente interessata dalla formazione di una struttura antiforme (risorgenza intra-calderica) il cui tasso di sollevamento è stato comparabile con l’innalzamento eustatico nell’intervallo Pleistocene superiore – Olocene [Lambeck et al., 2011]. A circa 10 ka B.P. il settore centrale della struttura risorgente raggiunge l’esposizione subaerea (terrazzo morfologico de “La Starza”). La calibrazione dei profili sismici Chirp con markers tefro-stratigrafici riconosciuti in un carotaggio e datati al 1538 A.D., 79 A.D. indica l’instaurarsi di un periodo di subsidenza in epoca post-Romana, registrato dall’annegamento di 10-25 m del cuneo di progradazione infralittorale rispetto alle profondità di equilibrio funzionale attualmente segnalate in area Mediterranea. L’interpretazione sismostratigrafica rivela, inoltre, la presenza di fluidi che risalgono attraverso la zona di faglia anulare che delimita la caldera del TGN. Bibliografia Lambeck, K., Antonioli, F., Anzidei, M., Ferranti, L., Leoni, G., Scicchitano, G., Silenzi, S., (2011). Sea level change along the Italian coast during the holocene and projections for the future. Quaternary International, 232, 250-257

Seismic expression of the shallow structure of The Neapolitan Yellow Tuff (NYT) caldera offshore the Campi Flegrei

In this study we integrate high-resolution swath bathymetry, single-channel reflection seismic data and gravity core data, to provide new insights into the shallow structure and latest Quaternary to Holocene evolution of the submerged sector of the Neapolitan Yellow Tuff (NYT) caldera (Campi Flegrei) in the Pozzuoli Bay. The new data allow for a reconstruction of the offshore geometry of the NYT caldera collapse \u2013 ring fault system, along with the style and timing of deformation of the inner caldera resurgence. Our interpretation shows that the NYT eruption (~15 ka BP) was associated with a caldera collapse bounded by an inward-dipping ring fault system. The ring fault system consists in a 1-2 km wide fault zone that encircles an inner caldera region ~ 5 km in diameter and is often marked by the occurrence of pore fluids ascending through the fault zone, up to the seafloor, particularly in the western sector of the bay. A shallow magmatic intrusion along the ring fault zone was also detected offshore Bagnoli in the eastern part of the Pozzuoli Bay (Sacchi et al., 2014). Following the NYT eruption, the inner caldera region underwent significant deformation and resurgence with a maximum cumulative uplift of the offshore structure in the order of 180 m. The net uplift rate of the caldera resurgent dome was ~ 9 - 12 mm/year during the period 15.0 \u2013 6.6 ka BP. The style of deformation of the resurgent structure can be described in terms of a broad doming, accompanied by subordinate brittle deformation, mostly concentrated in a small apical graben at the summit of the resurgent dome (Cole et al., 2005). Chronostratigraphic calibration of seismic profiles obtained by three tephra layers cored in the Pozzuoli Bay indicates 5 to 25 m of post-Roman differential subsidence and tilting towards ESE of the inner caldera resurgence, as recorded by the drowning of the infralittoral prograding wedge below the present-day storm wave base

The Neapolitan Yellow Tuff caldera offshore the Campi Flegrei: Stratal architecture and kinematic reconstruction during the last 15 ky

In this study we integrate high-resolution swath bathymetry, single channel reflection seismic data and gravity core data, to provide new insights into the shallow structure and latest Quaternary to Holocene evolution of the submerged sector of the Neapolitan Yellow Tuff (NYT) caldera (Campi Flegrei) in the Pozzuoli Bay. The new data allow for a reconstruction of the offshore geometry of the NYT caldera collapse\u2013ring fault system, along with the style and timing of deformation of the inner caldera resurgence. Our interpretation shows that the NYT eruption (~15 ka BP) was associated with a caldera collapse bounded by an inward-dipping ring fault system. The ring fault system consists in a 1\u20132 km wide fault zone that encircles an inner caldera region ~5 km in diameter and is often marked by the occurrence of pore fluids ascending through the fault zone, up to the seafloor, particularly in the western sector of the bay. A shallow magmatic intrusion along the ring fault zone was also detected offshore Bagnoli in the eastern part of the Pozzuoli Bay. Following the NYT eruption, the inner caldera region underwent significant deformation and resurgence with a maximum cumulative uplift of the offshore structure in the order of 180 m. The net uplift rate of the caldera resurgent dome was ~9\u201312 mm/year during the period 15.0\u20136.6 ka BP. The style of deformation of the resurgent structure can be described in terms of a broad doming, accompanied by subordinate brittle deformation, mostly concentrated in a small apical graben at the summit of the resurgent dome. Chronostratigraphic calibration of seismic profiles obtained by three tephra layers cored in the Pozzuoli Bay indicates 5 to 25 m of post-Roman differential subsidence and tilting towards ESE of the inner caldera resurgence, as recorded by the drowning of the infralittoral prograding wedge below the present-day storm wave base

Flood Historical Data for Flood Risk Estimation in Coastal Areas, Eastern Tyrrhenian Sea, Italy

A reconstruction of historical floods occurred along the Amalfi coast, during the last five 7 centuries is presented. The analysis of historical sources allowed to achieve a chronological 8 reconstruction of more than 100 floods, four of which classified as catastrophic events. In this 9 task, the level of information was decisive to carry out space–time identification, estimate the 10 affected area and define the type of damage to the structures, and the environment (e.g. mud 11 flow, debris flow, rock falls, shoreline progradation, fan deltas), which may be relevant for the 12 recognition of similar events within the geologic record. The magnitude of the events was 13 finally estimated, taking into account the size of the areas affected by flooding as well as the 14 type of effects induced on the urban and physical environment and the recurrence intervals

The composite dataset of the present-day Infralittoral Prograding Wedges (IPWs) in the inner continental shelf of the Campania region (Central-Eastern Tyrrhenian Sea)

This article reports on the dataset gathered following the census of 83 present-day Infralittoral Prograding Wedges (IPWs), surveyed on the inner continental shelf of the Central-Eastern Tyrrhenian Sea. The purpose of the census was to explore their bathymetric range and assess the observational laws governing this variability. The ensued dataset (Campania Region IPW Dataset, CRID) includes geographic, topographic and morpho-bathymetric indices, descriptive of each IPW and more, the exposure of each IPW to wave forcing (Geographical fetch, Effective fetch and extreme significant wave height, HS). In this work, histograms contribute to describe all the variables and highlight the dominant features of each IPW. Location maps univocally links the geographic position of each IPW to the appropriate attribute record in the dataset. Further, thematic maps illustrate eight wave fields obtained by offshore-to-nearshore transformation by as many sea states scenarios with 200-year return period. Such wave fields are used as sources for significant wave height representing wave conditions over each IPW. This dataset could be implemented with new measures at a broader scale, by following analogue procedures for measurements, to enlarge the observational scale on IPWs and improve the numerical models which might eventually derive by the analysis of this dataset

Flood Risk Estimation through Document Sources Analysis: the Case of the Amalfi Rocky Coast

In the last century the Amalfi Coast was affected by numerous severe floods in conjunction with exceptional rainfall that caused major damage in terms of lost lives and economic cost. Historical documentary sources are an important source of information for reconstructing exceptional flood events occurring prior to the instrumental era. Historical analysis also provides an opportunity to extend the time scale window for flood risk studies. To study historical floods we collected all the available information concerning the period between the 16th and the 20th centuries by analysing both published and unpublished sources. The great variety of historical sources made it necessary to formulate an ad hoc scientific procedure that takes into account not only the completeness and reliability of documents related to the period, but also the intrinsic quality of the material. Experience in historical data collection shows that not all documentary sources can provide useful information for flood characterization, but it is necessary to have a selective criteria in order to obtain the best information rather than the best dataset quality. Analysis of the data in question allowed us to achieve a chronological reconstruction of more than 100 floods. In this task, the level of information was decisive to carry out space–time identification, estimate the affected area and define type of damage to public and private structures, and the geological effects induced

The collaborative communication model for patient handover at the interface between high-acuity and low-acuity care

Background: Cross-unit handovers transfer responsibility for the patient among healthcare teams in different clinical units, with missed information, potentially placing patients at risk for adverse events. Objectives: We analysed the communications between high-acuity and low-acuity units, their content and social context, and we explored whether common conceptual ground reduced potential threats to patient safety posed by current handover practices. Methods: We monitored the communication of five content items using handover probes for 22 patient transitions of care between high-acuity ' sender units' and low-acuity 'recipient units'. Data were analysed and discussed in focus groups with healthcare professionals to acquire insights into the characteristics of the common conceptual ground. Results: High-acuity and low-acuity units agreed about the presence of alert signs in the discharge form in 40% of the cases. The focus groups identified prehandover practices, particularly for anticipatory guidance that relied extensively on verbal phone interactions that commonly did not involve all members of the healthcare team, particularly nursing. Accessibility of information in the medical records reported by the recipient units was significantly lower than reported by sender units. Common ground to enable interpretation of the complete handover content items existed only among selected members of the healthcare team. Conclusions: The limited common ground reduced the likelihood of correct interpretation of important handover information, which may contribute to adverse events. Collaborative design and use of a shared set of handover content items may assist in creating common ground to enable clinical teams to communicate effectively to help increase the reliability and safety of cross-unit handovers