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International audience; The Fucino Basin, central Italy, with its long and continuous history of Quaternary sediment accumulation, is one of the richest Mediterranean Middle Pleistocene tephra records. Here, we present a new detailed investigation of tephra layers (tephras) of the 250-170 thousand years before present (ka) interval, corresponding to the entire Marine Isotope Stage (MIS) 7 and parts of the MIS 8 and MIS 6. The investigated tephras have been characterised in terms of major, minor and trace elements, Sr-Nd isotopic compositions and 40Ar/39Ar ages. For correlation purposes, glass compositions and several new 40Ar/39Ar ages of selected proximal pyroclastic units spanning the same temporal interval from Vulsini (Latera Volcanic Complex), Sabatini, and Vico volcanic systems, central Italy, were measured. The late MIS 8-early MIS 6 Fucino tephras were backtracked to their corresponding volcanic sources, which include the Vulsini, Vico, Sabatini, Roccamonfina, Ischia and Campi Flegrei volcanic systems. While some of these tephras have been correlated to specific eruption units, other layers are currently not documented or described in near-vent sections, thus highlighting previously unrecognised events generated by these volcanic systems. Furthermore, the new high precision 40Ar/39Ar ages provide improved temporal constraints for Fucino making it one of the most detailed and chronologically best constrained tephra records for central Mediterranean MIS 7 tephrochronology. The Fucino record thus provides new integrative information for reconstructing the explosive history of Italian volcanoes during the investigated time interval. Furthermore, the geochronological constraints provide the basis for future paleoclimatic investigations at local and regional scale.

International audience; A full review of the 79 CE Plinian eruption of Vesuvius is presented through a multidisciplinary approach, exploiting the integration of historical, stratigraphic, sedimentological, petrological, geophysical, paleoclimatic, and modelling studies dedicated to this famous and devastating natural event. All studies have critically been reviewed and integrated with original data, spanning from proximal to ultradistal findings of the 79 CE eruption products throughout the Mediterranean. The work not only combines different investigation approaches (stratigraphic, petrological, geophysical, modelling), but also follows temporally the 79 CE eruptive and depositional events, from the magma chamber to the most distal tephras. This has allowed us first to compile a full database of all findings of those deposits, then to relate the products (the deposits) to the genetic thermomechanical processes (the eruption), and lastly to better assess both the local and regional impacts of the 79 CE eruption in the environment. This information leads to a number of open issues (e.g., regional environmental impact vs. local pyroclastic current impact) that are worthy of further investigations, although the 79 CE eruption of Vesuvius is one of the best studied eruptions in volcanology. The structure of the work follows three macro-categories, the historical aspects, the products, and the processes of the 79 CE eruption. For each investigation approach (from stratigraphy to modelling), all dedicated studies and original data are discussed. The open issues are then synthesized in the discussion under a global view of Plinian eruptions, from the magma setting to its dispersion as pyroclasts flowing on the surface vs. falling from the volcanic plume. In this way, a lesson from the past, in particular from the well-studied 79 CE eruption of Vesuvius, will be of help for a better synchronization of processes and products in future developments. Lastly, various aspects for volcanic hazard assessment of Plinian eruptions are highlighted from the tephra distribution and modelling points of view, as these large natural phenomena can have a larger impact than previously thought, also at other active volcanoes.

Here we present a multiproxy record (?13C, ?18O, major and minor element composition, mineralogy, and low-resolution biogenic silica content) from a lacustrine succession in the Sulmona Basin, central Italy. Based on previous tephrochronological constraints and a new 40Ar/39Ar dating of a tephra matching the widespread X-6 tephra, the record spans the ca. 129-92 ka period and documents at sub-orbital scale the climatic and environmental changes over the Last Interglacial and its transition to the Last Glacial period. The ?18O composition is interpreted as a proxy for the amount and seasonality of local precipitation, whereas variations in elemental and mineralogical composition are inferred to reflect climatic-driven changes in clastic sediment input. The observed variations are consistent among the different proxies, and indicate that periods of reduced precipitation were marked by enhanced catchment erosion, probably due to a reduction in vegetation cover. The first part of the Last Interglacial shows the most negative ?18O values. Comparison with pollen records from the Mediterranean suggests a greater seasonality of the precipitation at this time. At millennial-to-centennial time scales, comparison of the Sulmona record with speleothem ?18O records from central Italy highlights a highly coherent pattern of hydrological evolution, with enhanced variability and similar events of reduced precipitation consistently recorded by each isotope record. The observed intra-interglacial variability can potentially be linked, within the uncertainties associated with each age model, to similar variations observed in sea-surface temperature records from the Mediterranean and the North Atlantic, suggesting a link between Mediterranean hydrology and North Atlantic temperature and circulation patterns that persists during periods of low ice volume.

A review of the existing chronological, stratigraphic and chemo-petrologic data of the major eruptive units from the early phase of activity (800–390 ka) in the Monti Sabatini Volcanic District (MSVD), belonging to the ultra-potassic magmatic region of central Italy, is presented along with new radioisotopic age determinations and geochemical analyses. Through the combined use of electron microprobe glass compositions, selected trace-element compositions, and single-crystal 40Ar/39Ar age determinations, we provide a new chrono- and chemo-stratigraphic classification of the products emplaced in the 800–390 ka time interval. Besides giving insights on the petrologic evolution of the Roman Comagmatic Region, the large dataset provides fundamental information that is applicable to tephrostratigraphic studies in the wide region encompassing the Tyrrhenian Sea margin to the Adriatic Sea basin. Distal tephras from this volcanic activity also act as important geochronologic markers for the coastal sedimentary successions deposited in response to glacio-eustatic fluctuations, as well as for successions in the Quaternary tectonic basins of the Central and Southern Apennines. An innovative approach based on the use of discrimination diagrams of Zr/Y vs Nb/Y ratios for fingerprinting altered volcanic rocks – recently developed and successfully employed in archaeometric studies – is here combined to the glass compositions for classifying the MSVD deposits and tested on two distal tephra layers, showing its potentiality for tephrostratigraphic correlation.

Morphological, stratigraphical and structural investigations integrated with palaeomagnetic and tephrostratigraphic studies and 40Ar/39Ar measurements allowed us to define the Quaternary tectonic–sedimentary evolution of the epicentral area of the L'Aquila 2009 earthquake (Mw 6.3). This area roughly matches the Paganica–San Demetrio–Castelnuovo (PSC) intermountain basin filled by a fluvio-lacustrine succession that is variously deformed by normal faults. At its early stage (Early Pleistocene; ca 2 Ma), the basin hosted a lake that was characterised by whitish carbonate silt and mud deposition. Towards the end of the Early Pleistocene, this was partly filled by a south-eastward prograding deltaic system. The south-easternmost portion of the deltaic system was successively abandoned and eroded, while sedimentation of a braided river system developed in a smaller area westwards. Before 780 ka, this fluvio-lacustrine system (the Lower PSC syntheme) ended, and the area underwent erosional and pedogenic processes. These processes continued up to >460 ka, with the onset of fluvial gravel and volcanic-rich silty sand deposition over a narrow area of the south-western PSC basin (an earlier unit of the Upper PSC syntheme, early Middle Pleistocene). Around 460 ka, when most of this area was again subjected to denudational processes, the sedimentation migrated into the previously exposed north-western area of the PSC basin, where fluvial/alluvial sediments were deposited, between ca 460 ka and ca 350 ka (a later unit of the Upper PSC syntheme). Between ca 350 ka and the present, the sedimentation continued uninterrupted in a slight westwards restricted area of the PSC basin (Upper–Late PSC syntheme). The significant contraction of the basin, the shifting of its depocentre, the variation in its geometry and in the spatial distributions and thicknesses of the units constituting the Lower, Upper and Late PSC synthemes, provide evidence for strong tectonic control. This resulted in progressive reduction of the activity of the south-easternmost tectonic structures and parallel migration of the fault activity on the westernmost structures. In this perspective, the fault system responsible for the L'Aquila 2009 earthquake can be seen as the most recent expression of a long-lasting westwards polarised process of tectonic activity transfer.

On 6 April, 2009, a Mw 6.3 earthquake struck L’Aquila and dozens of neighbouring villages (Abruzzo, central Italy) causing 308 deaths and with thousands injured. Within Italian seismicity, this was the strongest event since 1980 (Irpinia; Mw 6.9), and the first located so close to a large city since 1908 (Messina; Mw 7.3). Consistent data from an integrated approach (including stratigraphy, geomorphology, tephrochronology and paleoseismology) have allowed us to identify a 19-km-long, hitherto poorly known structure as being responsible for this earthquake (Paganica–San Demetrio fault system, PSDFS). The fingerprinting of four well-dated tephra layers and a detailed outline of the geomorphological and stratigraphic setting have provided the basis for assessing the behaviour of the PSDFS since its early activity, here dated at least ca 500 ka, to the present. The slip rate of the structure, calculated over different time windows, has fluctuated slightly ca 0.5 mm/yr. Paleoseismological analyses revealed the traces of the last surface-faulting events; thus, we unambiguously recognise the offset associated with the Mw 6.7 earthquake of 1703, which was previously related to other conterminous structures, along with an older comparable strong event, speculatively ascribed to an event purely known as the AD 801 central Apennine earthquake. This study shows that a long-term to short-term integrated approach is crucial in seismic hazard evaluation, especially when dealing with fault systems that are difficult to trace geomorphically, despite being capable of generating 2009-like earthquakes or even stronger events when conterminous structures are also involved.

Significant new information shows that the Campanian Ignimbrite (CI) eruption from the Phlegrean Fields, southern Italy, was much larger than hitherto supposed and in fact one of the largest late Quaternary explosive events. The eruption can be dated to 40,000 calendar years ago, within the interval of the so-called Middle to Upper Paleolithic 'transition'. Its position can be precisely correlated with a number of other environmental events, including Heinrich Event 4 (HE4), the Laschamp excursion, and a particular cosmogenic nuclide peak. In view of this unique combination of factors, we studied the CI volcanic catastrophe with particular attention to its impact on climate and human ecosystems, including potential interference with ongoing processes of cultural evolution (biological evolution is best left aside for the moment). The contribution of this research is chronological and ecological. The CI volcanic event provides an unequalled means of correlating stratigraphic sequences across Western Eurasia, either directly or indirectly, and affords a unique opportunity to establish the age and climatic context of important archaeological sequences. Ecologically, the CI eruption inevitably interacted with the beginning of HE4 in terms of atmospheric feedback systems. Their combined forcing produced a sudden and at least hemispheric climatic deterioration; a 'volcanic winter' scenario cannot be ruled out. Paleolithic occupation was severely altered throughout the direct-impact zone of the eruption and likely along fringe areas in southern and southeastern Europe. The above observations call for a reconsideration of the processes and rhythms involved in the Middle to Upper Paleolithic 'transition'. A tentative model is suggested that links the exceptional environmental stress at 40,000 BP with processes already active in Paleolithic societies, leading to a period of accelerated change in cultural configurations. These eventually evolved into an Upper Paleolithic proper at a later date. The evidence to invoke allochthonous cultural input or invasionist scenarios is not considered compelling.

The Campanian Ignimbrite (CI) eruption, dated by 40Ar/39Ar and various stratigraphic methods to ca. 39,000 cal BP, generated a massive ash plume from its source in southern Italy across Southeastern and Eastern Europe. At the Kostenki-Borshchevo open-air sites on the Middle Don River in Russia, Upper Paleolithic artifact assemblages are buried below, within, and above the CI tephra (which is redeposited by slope action at most sites) on the second terrace. Luminescence and radiocarbon dating, paleomagnetism, and soil and pollen stratigraphy provide further basis for correlation with the Greenland and North Atlantic climate stratigraphy. The oldest Upper Paleolithic occupation layers at Kostenki-Borshchevo may be broadly correlated with warm intervals that preceded the CI event and Heinrich Event 4 (HE4; Greenland Interstadial: GI 12-GI 9) dating to ca. 45,000-41,000 cal BP. These layers contain an industry not currently recognized in other parts of Europe. Early Upper Paleolithic layers above the CI tephra are correlated with HE4 and warm intervals that occurred during 38,000-30,000 cal BP (GI 8-GI 5), and include an assemblage that is assigned to the Aurigancian industry, associated with skeletal remains of modern humans.

Morphologic investigations along the Campo Felice (CF) fault (central Apennines, Italy) have been made in order to develop a procedure for the paleoseismological analysis of bedrock fault scarps. The CF fault has been responsible for the formation of an impressive limestone fault scarp. Geomorphologic work on the CF basin and related fault indicated that the scarp originated from tectonic fault displacements. Three morphologic units have been distinguished along the fault scarp and defined as morphosome M1 (lowest part of the scarp), M2 and M3 (the uppermost part). These units display different karstic features, which are the result of their different duration of exposure to weathering. Micromorphologic analyses focused on the morphosome M1, along which the CF fault plane is exposed for a height ranging between 4 and 7 m. These analyses were aimed at defining differently weathered bands located at various heights, and parallel to the fault scarp top and base. The presence of these bands suggests repeated fault movements. The exposed fault surface displays a low-grade biokarstic weathering due to the action of epilithic and endolithic organisms. The biokarst distribution is, however, inhomogeneous and conditioned by the presence of nourishing elements, moisture and by light intensity. An area preferentially affected by the biokarstic processes develops as a band at the bedrock–soil contact at the base of the scarp. Roughness and colour analyses were made to identify uplifted bands which previously formed at the bedrock–soil contact. The roughness analysis was made using a microroughness-meter along 20-cm long horizontal transects repeated each 20 cm of fault height for the entire morphosome M1, at various sites along the scarp. The roughness variance data, plotted vs. the fault height, failed to identify differently weathered bands of paleoseismological interest. This result is probably due to the complex distribution of biokarst along the investigated fault plane. More reliable results have been obtained by areal analysis of the variation of the colour rendering of the rocks exposed along the fault plane at different sites. Photographic images of large portions of fault surfaces have been processed with standard graphic computer programs. The variations of colour indicated the presence of bands at various heights along the fault plane. Two uplifted bands have been recognised at all the investigated sites suggesting two displacement events (E1 and E2). A preliminary chronological framework for these two events, the youngest of which affected the CF fault, can be derived from the paleoseismological data available for the southernmost branch of the regional fault system that includes the CF fault. According to these data, E1 may have occurred between 860 and 1300 AD, while E2 may have occurred at about 1900 BC. Work is in progress to define surface exposure ages of different parts of the fault plane by means of in situ produced cosmogenic 36 Cl. This procedure will give further chronological constraints for the age of E1 and E2 and will also permit to test the validity of the micromorphologic analysis of bedrock fault scarps for paleoseismological aims.