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Volcanic eruptions are driven by magma rising through Earth’s crust. The style of an eruption depends on intrinsic and extrinsic parameters and is commonly a dynamic process. Thorough investigation of the related products is fundamental to understanding eruptive phenomena.In this context, quantitatively constraining the dispersal area, grain size distribution and pyroclast textures is essential. Volume determination of pyroclasts is fundamental to constrain density and porosity. However, volume determination of irregularly shaped pyroclast cannot be done with geometrical laws but hat to be assessed with different methodologies. In this study, we have collected a set of clasts from Santorini, Greece, to test three methodologies: a manual methodology to measure three orthogonal axes with a calliper; an optical methodology to measure longest and shortest axis through multiple photographs; and the Archimedean methodology.All three methodologies found similar volume results with little impact on the subsequent assessment of porosity and density. The discrepancy between Archimedean and manual/optical methodologies is observed to be smaller than the revealed natural variability. For this reason, we advertise the manual methodology to be used for future field campaigns as a simple and fast yet reliable approach to gain insights into the textural state of magma at eruption., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The study deals with a review of pre-eruptive dynamics and evidences of open-system behavior in the volcanic plumbing system beneath Campi Flegrei Caldera (CFC), together with estimates of magma residence time and ascent (mixing-to-eruption timescales).In detail, we compile pre- and syn-eruptive dynamics reported in the literature for Campanian Ignimbrite (~ 40 ka), Neapolitan Yellow Tuff (~ 15 ka), and more recent activity. After summarizing geochemical and textural evidence, we observe a fingerprint of open-system dynamics in the deposits associated to CFC volcanic activity of the last 40 ky. Geophysical and petrological investigations allow us to hypothesize the structure of the magma feeding system: we point at a 9-km deep main storage reservoir that feeds and interacts with shallow reservoirs, mainly 2–4 km deep.Thus, we define a scenario depicting pre-eruptive dynamics of a possible future eruption and provide new constraints on timescales of magma ascent with a physical model based on magma-driven ascending dyke theory. Results show that considerably fast ascent velocities (in the order of m/s) can be easily achieved for eruptions fed by both shallow ( 3–4 km) and deep ( 9 km) reservoirs. Comparing experimental and numerical approaches, it emerges that mixing-to-eruption timescales occurring at shallow reservoirs could be in the order of minutes to hours. Thus, our timescale estimates (magma ascent and mixing to eruption), imply that explosive eruptions could begin with little physical ‘warning’, of the order of days to months. In this case, the onset of volatile saturation might provide pre-eruptive indicators.&nbsp, The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The El Abrigo member of the Diego Hernández Formation (Tenerife, Canary Islands) represents the final (170 ka) and most voluminous eruption (>20 km3 DRE) of the last cycle of explosive activity of the Las Cañadas volcano. It is a dominantly phonolitic ignimbrite containing both mafic and banded pumices, suggesting that magma mixing played an important role in triggering the eruption and modulating eruptive dynamics. Here we use petrology, together with glass and mineral geochemistry of enclave-rich mafic scoriae, banded and phonolitic pumices from El Abrigo ignimbrite, to shed light on the pre-eruptive storage conditions and processes governing magma ascent and interaction dynamics and to provide a first-order assessment of the contribution of magma mixing and crystal mush melting to the dynamics of this eruptive event. The distribution of major elements in glasses is consistent with diffusive exchange between the interacting melts whereby Na transfers from the phonolite to the tephriphonolitic melt. However, V, Zr, Ba and Eu suggest a complex scenario in which an intruding tephritic to phonotephritic magma interacted with two distinct zones of a phonolitic magma chamber, one occupied by a crystal rich, low-Zr and high Ba phonolite, and the other by an evolved, crystal poor, high-Zr phonolite. These results, coupled with mineral-melt thermobarometry, allow us to reconstruct the Las Cañadas plumbing system at the end of the Diego Hernández cycle, and to evaluate the contribution of cumulate mush melting and magma mixing in as follows: (1) the parental tephritic magma was stored at or near the Moho (410-450 MPa) at 1050°C where it was periodically replenished by more primitive basanitic magma; (2) upon ascent, the tephrite intruded into a shallow and zoned phonolitic storage system, triggering the disruption of a crystal mush in its base, and (3) subsequently interacted with a crystal-poor zone within the reservoir. Energy balance evaluations suggest that relative mafic volume ratios ranged between 20 and 43 vol %, and the conservation of small-scale magma mingling structures and their geochemical distribution suggest that the mixing event took place very shortly before the eruption, on a timescale of hours.

Objective: The aim of the present study was to assess the prevalence and incidence of pressure ulcers (PUs) in patients hospitalized in a University Hospital in central Italy. Methods: We carried out a prevalence and incidence study on PUs and an additional prevalence estimate of PUs was also produced ten days after the first assessment. All data were explored by descriptive statistics, the Chi-square test and a multivariate analysis. Results: The prevalence of pressure ulcers was of 6,5%, while it increased to 9,9% at the second assessment ten days after the first measurement. Prevalence was statistically significant and increased with the age of inpatients (p=0,004) and was correlated to the origin of the patients (p=0,002). The incidence of PUs ten days after hospital admittance was of 3,6%. Ulcers are more frequently observed in the general medicine rather than in the surgery and intensive care units. Results showed that there exists a meaningful relationship between increased risk (Braden 16) and the presence of PUs, with an OR of 1,40 (95% CI 1,03-1,62) in high risk patients (Braden -12) and with an OR of 1,61 (95% CI 1,06-2,42) in very high or prohibitive risk patients (Braden 13-16). The most affected areas are the sacrum, the heels and the ankles. Mobilization plans were scarcely available, or do not described. Conclusions: The obtained data confirmed the difficulty to measure whether PU prevention practices are being carried out in compliance with the set guidelines presently in use in all the University Hospital Units. There is still a very limited use of available risk assessment tools for predicting PU risk and mobilization plans are still poorly documented. A monitoring and follow-up strategy should be implemented to better understand prevalence and incidence rates.

The El Abrigo member, belonging to the Diego Hernández Formation (Tenerife, Canary Islands), represents the final (0.179 Ma) and most voluminous eruption (>20 km3 DRE) of the last cycle of explosive volcanism of the Las Cañadas volcano. Its products are predominantly phonolitic, but both mafic scoriae and banded pumices are commonly found, suggesting that El Abrigo eruption was triggered via the input of fresh, more mafic magma into a shallow, phonolitic magma chamber. A petrological and geochemical study was carried out on a variety of pumices sampled in the El Abrigo member, ranging from dominantly mafic to banded, and in turn to phonolitic. Banded pumices show a diversity of textures varying from coarsely to finely banded. Mafic scoriae host numerous phonolitic enclaves, sometimes grading to banded within a hand sample. In contrast, phonolitic pumices are homogeneous, almost crystal-free and highly vesicular. Small-scale, fluidal mixing structures are widely present in SEM BSE images and involve the entire compositional spectrum from a partially-crystallized tephriphonolitic composition (SiO2 ~52 wt.%; MgO ~3 wt.%) to a phonolitic melt (SiO2 ~61 wt.%; MgO ~0.3 wt.%). The distribution of fast-diffusing versus slow-diffusing elements indicates that diffusive hybridization has played a significant role. The presence of such small-scale structures and high compositional gradients at scales in the order of tens to hundreds of microns suggest that mixing was of limited efficiency and that the eruption likely started shortly after the beginning of this process, as longer timescales would erase such heterogeneities by advection and chemical diffusion. Several mineral and mineral-melt thermobarometric methods show good agreement and suggest that the mafic end-member had a tephritic composition and was stored prior to the mixing event at ~400 MPa (lowermost oceanic crust) and 1050ºC, and both endmembers contained ~3 wt.% dissolved H2O.

Trace element abundance and isotopic composition determinations of distal tephra levels is not currently a routine analysis, so the main objective of this work was to obtain full geochemical and isotopic data on well-known regional markers, aiming at enriching the comparison data-base for future tephrostratigraphic investigations. We chose to work on distal tephra embedded in the San Gregorio Magno (SGM) lacustrine sequence (Campania, Southern Italy) because its high sedimentation rates, should make it easier to avoid the problems linked to the mixing of volcanic fragments related to different explosive events occurred very close in time. Where necessary, due to the lack of data on comparison tephra from literature, marine distal equivalent were also fully characterized. The main tephra layers extracted from both sequences, already characterized as to major element composition (Munno and Petrosino, 2007; Morabito et al.,2014; Petrosino et al., 2016), were analyzed through LA-ICP-MS to evaluate the abundance of trace elements. The isotopic composition has been measured on a hand-picked glass amounts and when possible on minerals. The results of these analyses made it possible to refine some correlations previously hypothesized, as that of sample SGM16, which definitely results the distal counterpart of Monte Epomeo eruption of Ischia Island, aged ca. 55 ka, and well repeats the composition of the widespread tephra marker Y-7. The bimodal composition of layer SGM11 is confirmed by the trace element abundance, and only one of the two compositions (Na2O/K2O ca. 0.45) fully corresponds to that of marker X-5 (ca. 105 ka), here firstly fully characterized in a marine sequence from a Tyrrhenian sea core. The glass fragments displaying a different chemical composition (Na2O/K2O ca. 0.9) are probably the product of the reworking of the slightly older tephra SGM10, the distal counterpart of marker X-6 (ca. 109 ka). Few tephra layers are deeply altered, as evidenced by the high amount of clay minerals found by XRD analyses and for such a reason the results of 87Sr/86Sr and 143Nd/144Nd isotopic analysis on their glasses were not reliable. To bypass the problems linked to secondary alteration, where possible, we analyzed feldspar crystals, less prone than glass to chemical alteration, and obtained better results. In conclusion, the data produced in this work highlight that the full geochemical characterization of tephra levels, integrated by isotopic data, makes it possible to identify their source and, in most cases, to correlate them to a specific well known eruptive event. Morabito, S., Petrosino, P., Milia, A., Sprovieri, M., Tamburrino, S. (2014). A multidisciplinary approach for reconstructing the stratigraphic framework of the last 40ka in a bathyal area of the eastern Tyrrhenian Sea. Global and Planetary Change, 123, 121-138. Munno R., Petrosino P. (2007). The late Quaternary tephrostratigraphical record of the San Gregorio Magno basin (southern Italy). Journal of Quaternary Science, 22, 247-266. Petrosino, P., Morabito, S., Jicha, B. R., Milia, A., Sprovieri, M., Tamburrino, S. (2016). Multidisciplinary tephrochronological correlation of marker events in the eastern Tyrrhenian Sea between 48 and 105 ka. Journal of Volcanology and Geothermal Research, 315, 79-99.