Abstract The interpretation of high-resolution seismic profiles acquired close the eastern coast of the Bay of Naples offshore Somma–Vesuvius volcano, and calibrated by borehole data, allowed us to recognize a reflection-free seismic facies consisting of a volcaniclastic debris avalanche overlain by pyroclastic density current deposits. Both are associated with the 3.5 ka ‘Avellino eruption’ and are in turn overlain by a marine succession. The top of the volcaniclastic unit corresponds to a deep erosional surface covered by a coarse-grained bioclastic layer with rounded pumice. We argue that these features are related to a tsunami that was triggered by the sudden entrance into the sea of the gigantic (>1 km 3 ) volcaniclastic unit. The onshore–offshore correlation and mapping of this volcaniclastic unit have allowed us to evaluate its distribution west of Somma–Vesuvius. The pyroclastic density current deposits terminate seaward at 40 m water depth; at the same depth the debris avalanche is affected by a gravitational instability. Over the last 3.5 ka the slump has been in constant movement, as documented by the angular unconformities at the top of the chaotic seismic unit and within the overlying marine deposits.

Abstract During the Bronze Age, Vesuvius had a Plinian eruption whose deposits are known as the Avellino Pumice. The eruption spread a blanket of white and grey pumice across southern Italy, and there was a severe impact on proximal areas. Assessment of volcanological factors for the Plinian phase gives intensities of 5.7 × 10 7 kg s -1 for the white pumice phase and 1.7 × 10 8 kg s -1 for the grey pumice phase, corresponding to column heights of 23 and 31 km, respectively. Volume (magnitude) calculations using the crystal concentration method (CCM) give respectively 0.32 and 1.25 km 3 of deposit, in a total minimum period of about 3 h. Archaeometric studies on Bronze Age domestic pottery from several settlements in Apulia (SE Italy) reveal the presence of pumice fragments mixed with the clay, and petrological and chemical criteria suggest that these pumices are from the Avellino eruption. This relationship allows us to fix precise correlations between different archaeological facies of the Italian Bronze Age. To explore the possibility of an extensive use of pumices in these distal regions (about 140 km from Vesuvius), we calculated the possible thickness of the tephra blanket. We propose a method to extrapolate proximal data on the deposit to calculate its minimum distal thickness. Such a method could also be used in volcanic hazard studies to assess the distal impact of large past eruptions.

Abstract Following the final phase of Pleistocene volcanism in the Latium region, the main craters of Albano and Nemi in the Colli Albani volcano started to accommodate a sedimentary sequence in both lakes of variable thickness. In the mid-1990s, an EU-funded interdisciplinary project (PALICLAS) investigated the palaeoenvironmental record of the sedimentary sequences of Lakes Albano and Nemi using a multi-proxy approach. A set of up to 14-m-long cores was recovered from the two maar lakes following a seismic survey. Detailed petrophysical (magnetic), sedimentological and geochemical analyses, combined with a large palaeoecological dataset including algal and bacterial pigments, biological remains such as pollen, diatoms, Cladocera, chironomids and ostracods were carried out in three selected sites in Lake Albano and one site in Lake Nemi. A robust chronology was established by integrating accelerator mass spectrometry (AMS) radiocarbon datings, pollen analysis and secular variation record of the magnetic field together with the identification of two tephra layers correlated with the Late Pleistocene Etnean eruption of Biancavilla (Y1; 17.2 cal ka BP) and the late Holocene Pomici di Avellino (4.1 cal ka BP). The compiled results of these investigations provide a detailed chronicle of the response of both lacustrine basins to climate- and anthropogenically triggered environmental changes in central Italy for the past c . 28 cal ka. The Lake Albano record further demonstrate that at least the earliest changes reflect distinct warm/cold cycles that triggered major lake level changes of millennial to centennial duration as a major response of the lacustrine basin to climate forcing. Alternatively, these dramatic lake level variations – also identified during the Holocene – could have been driven by CO 2 injections of possible magmatic origin. However, flickering interannual to interdecadal variations further identified within these cycles can be correlated to oscillations of the North Atlantic (NAO) as observed in Greenland ice cores, marine and other lacustrine records. The latter, thus, would favour the climatic rather than volcanic cause for these changes. The Holocene record in both lakes is characterized by organic-rich sediments with a variable development of lamination. Although human activity in the catchment is evident since the mid-Holocene, the global signal indicates that changes in climatic variables such as wind intensity, precipitation and temperature are the most probable factors producing these environmental changes. The response of both lake systems to probable warm/cold episodes during the late Holocene, however, is difficult to disentangle from the often-contemporaneous human impact on their catchments.