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Explosive eruptions at Stromboli volcano (Italy): a comprehensive geochemical view on magma sources and intensity range
No full textA comprehensive understanding of the processes that occur during magmatic storage and pre-eruptive ascent—and of their associated timescales—is critical to identifying potential precursory signals, and to developing robust volcano early-warning systems. Stromboli’s persistent activity comprises continuous degassing and explosive activity that ranges from hourly, low-intensity “normal” activity to occasional, more violent, paroxysmal activity. While the magma source processes that drive normal and paroxysmal activity are reasonably constrained, eruptive activity intermediate in magnitude and intensity (i.e., major explosions) remains elusive in terms of classification, source region, and pre-eruptive timescales. Here, we investigate the 19 July 2020 major explosion that geophysical parameters place at the upper limit of the major explosions field, close to small-scale paroxysms such as the 2003 and 2007 events. The geochemical signatures of matrix glass, olivine, melt inclusions, and embayments—integrated with gas measurements—highlight important differences in eruption source, ascent behaviour, and pre-eruptive timescales of the studied event when compared to paroxysms. Melt inclusion volatile contents identify that magma rise begins from a slightly shallower source (~9.5 km below sea level, b.s.l.) than for paroxysms (11.4 km b.s.l.), with the activation of a shallower ponding zone at 5–6 km b.s.l.. This, in combination with intermediate matrix glass compositions, suggests complex ascent behaviour, characterised by CO2 buffering in the deep ponding region and magma self-mixing in the shallower zone. Fe–Mg-diffusion modelling in olivine indicates a system perturbation start- ing ~20–25 days before eruption onset, in agreement with the timescale of volcanic gas CO2/SO2 ratio changes observed in the plume, and significantly shorter than that observed prior to paroxysms (~4 months). The geochemical dataset provides insights into the processes controlling the steady-state conditions and the broad spectra in eruption magnitude and intensity at Stromboli and bears important implications for eruption forecasting.Published34OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Engineering Geological and Geophysical Studies Supporting Finite Element Analysis of Historical Buildings after Dynamic Identification
No full textResonance frequencies of a masonry bell tower were estimated by means of ambient noise measurements and compared with those computed by using fixed base, Winkler, and FE numerical, including subsoil. Given the geological complexity that characterizes the subsurface of the analyzed area, despite the presence of massive volcanic outcrops near the bell tower, we carried out a geophysical characterization of the subsoil by using active and passive seismic surveys. These surveys have identified a soft substrate underneath the construction; for this reason, the dynamic identification of the tower was performed, including the interaction with the soil. The resonance frequencies of the masonry bell tower computed by the models are very similar to those obtained using ambient noise. Results suggest that building resonance frequencies, estimated by ambient noise surveys, can be used because of their reliability especially when quick analyses are required at historical buildings located in seismically active areas needing plan actions to reduce their vulnerability. Moreover, such analyses, being performed on samplings acquired within the structure, allow for estimating its dynamic response, taking into account the effect of subsurface characteristics as well.This work was funded by the project “CH2V—Cultural Heritage Hazard and Vulnerability” (University of Catania, Linea 2-PIACERI, funds granted to Giovanna Pappalardo).Published84JCR Journa
Temporal Variability in Gas Emissions at Bagana Volcano Revealed by Aerial, Ground, and Satellite Observations
No full textBagana is a remote, highly active volcano, located on Bougainville Island in southeastern Papua
New Guinea. The volcano has exhibited sustained and prodigious sulfur dioxide gas emissions in recent
decades, accompanied by frequent episodes of lava extrusion. The remote location of Bagana and its persistent
activity have made it a valuable case study for satellite observations of active volcanism. This remoteness has
also left many features of Bagana relatively unexplored. Here, we present the first measurements of volcanic
gas composition, achieved by unoccupied aerial system (UAS) flights through the volcano's summit plume,
and a payload comprising a miniaturized MultiGAS. We combine our measurements of the molar CO2/SO2
ratio in the plume with coincident remote sensing measurements (ground- and satellite-based) of SO2 emission
rate to compute the first estimate of CO2 flux at Bagana. We report low SO2 and CO2 fluxes at Bagana from
our fieldwork in September 2019, ∼320 ± 76 td −1 and ∼320 ± 84 td −1, respectively, which we attribute to
the volcano's low level of activity at the time of our visit. We use satellite observations to demonstrate that
Bagana's activity and emissions behavior are highly variable and advance the argument that such variability is
likely an inherent feature of many volcanoes worldwide and yet is inadequately captured by our extant volcanic
gas inventories, which are often biased to sporadic measurements. We argue that there is great value in the
use of UAS combined with MultiGAS-type instruments for remote monitoring of gas emissions from other
inaccessible volcanoes.BMK, EJL, and AA acknowledge the
financial support of the Alfred P Sloan
foundation, awarded via the Deep Carbon
Observatory. TR acknowledges funding
via the CASCADE programme, EPSRC
Programme Grant EP/R009953/1. CIS
acknowledges the financial support of the
New Zealand Earthquake Commission.Publishede2022GC010786OSV1: Verso la previsione dei fenomeni vulcanici pericolosiJCR Journa
Novel insights into the sea level evolution along the coast of Bozburun Peninsula (Turkey): A study on submerged Bronze Age harbor in Çamçalık
No full textA recent discovery of a Bronze Age harbor site in Çamçalık provides new data for the relative sea level history along the coast of the Bozburun Peninsula over the last 3600 years. In this study, we compared the new and previously published data from nearby sites to determine the long-term relative sea level changes. Further comparison of the observed sea level data and newly produced glacial isostatic adjustment (GIA) models clarified the tectonic contribution to the relative sea level changes. Our results suggest a nonlinear tectonic subsidence trend in the coastal zone since 3600 B.P. The increase in the relative sea level accelerated over the last 1400 years, mostly due to the seismic events controlled by the tectonic regime of the southeastern Aegean Sea. We can conclude that, as in the past, this active tectonic process will have a major impact on the future sea level evolution of the coastal sector of the Bozburun Peninsula. Notably, our study can be used to understand the historical trend of sea level rise while providing a foundation for future trend prediction.Published246-2604A. Oceanografia e climaJCR Journa
New insights into geological setting of the summit area of mount Etna volcano (Italy) inferred from 2D gravity data modelling
No full textGravimetric observations were carried out in 2015, to image the uppermost
portion of the volcanic plumbing system of Mt. Etna (Italy). Gravity
measurements were performed using two relative gravimeters, along a profile
that crosses the summit craters area (elevations between 2,820 and 3,280ma.s.l.).
Accurate positioning of the gravity observation points was determined through
GPS measurements. After applying elevation and terrain corrections, the reduced
gravity data were used to build a 2D density model of the uppermost part of the
volcano edifice. This model was constrained using to-date knowledge of the
structural setting of the area and the available volcanological data. We highlighted
the presence of low-density material below the summit craters, down to the depth
of about 2.1 km, interpreted as highly altered, fumarolized and structurally
weakened material. It is also likely that the close presence of the conduits
feeding the summit craters of the volcano contributes to the gravity low in the
SW half of the measurement profile. Conversely, the gravity low observed at the
northern edge of the profile could reflect the high concentration of faults and
eruptive fissures in the Pizzi Deneri area, in correspondence of the Ellittico
caldera rim.Published1171884OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
A New Installation for Geomagnetic Field Monitoring at Talos Dome, a Remote Antarctic Site Away from Permanent Observatories
No full textAn automatic geomagnetic station for monitoring the Earth’s magnetic field variations
was installed in December 2020 at Talos Dome, a remote site on the Antarctic Plateau, about 300 km
away from the permanent geomagnetic observatory at Mario Zucchelli Station (MZS). Designed and
assembled at the laboratory of electronics of the Istituto Nazionale di Geofisica e Vulcanologia (INGV)
in Rome, this autonomous station is formed by a vector magnetometer specifically manufactured by
Lviv Institute (Ukraine) for very low temperatures and a low-power system supplied by batteries
charged by a wind generator and solar panel. Data, sampled at 1 Hz, are locally stored and can
be downloaded once a year during the Antarctic summer expeditions. The goal was to integrate
observatory data for better monitoring the geomagnetic field from an uncovered Antarctic area. In
fact, it is well known that the distribution of geomagnetic observatories strongly favors the northern
hemisphere, and each new instrumental installation in Antarctica should be considered as a useful
attempt to balance the geomagnetic monitoring in the two hemispheres. The achieved goal was
to obtain a long data series, keeping the station working even during the austral winter when the
temperature can reach −60 ◦C; we recorded almost 11 months of data in one year and the station is
still operating. Data from the new station, jointly with data from permanent observatories, improve
the analysis of the magnetospheric dynamics and the ionosphere–magnetosphere coupling. Talos
Dome, together with the Italian geomagnetic observatory at Mario Zucchelli Station and New Zealand
geomagnetic observatory at Scott Base, constitutes a network along the 80◦S geomagnetic parallel,
which is interesting for studying the longitudinal propagation of geomagnetic signals of external
origin. In this work we present the characteristics of the station and of the data it provides, with the
aim of them for analysis in the framework of space weather.Published339OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa
SHAPEness: A SHACL-Driven Metadata Editor
No full textThe Shapes Constraint Language (SHACL) has been recently introduced as a W3C recommendation to define constraints for validating RDF graphs. In this paper a novel SHACL-driven multi-view editor is presented: SHAPEness. It empowers users by offering them a rich interface for assessing and improving the quality of metadata represented as RDF graphs. SHAPEness has been developed and tested in the framework of the European Plate Observing System (EPOS). In this context, the SHAPEness features have proven to be a valuable solution to easily create and maintain valid graphs according to the EPOS data model. The SHACL-driven approach underpinning SHAPEness, makes this tool suitable for a broad range of domains, or use cases, which structure their knowledge by means of SHACL constraints.Published274–288OST5 Verso un nuovo Monitoraggi
Ostracod and Foraminifer Responses to Late Pleistocene–Holocene Volcanic Activity in Northern Victoria Land as Recorded in Ross Sea (Antarctica) Marine Sediments
No full textThe impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated similar response patterns associated with the deposition of material from volcanic eruptions. In particular, based on the palaeontological evidence, it was possible to divide the cores into four intervals/phases recording the evolution of the ecosystem before and after the deposition events: (1) Pre-extinction phase (high abundance and high diversity values). (2) Extinction phase, characterised by the complete disappearance of ostracod fauna; the foraminiferal assemblage, although not entirely absent, records extremely low values of abundance and diversity (survivor assemblage). (3) Recovery phase (increasing abundance and diversity values), characterised by the recolonisation of some opportunistic taxa; species such as Australicythere devexa and Australicythere polylyca dominate the ostracod assemblage. (4) Post-extinction phase (high abundance and high diversity values), with the return to an environmental equilibrium characterised by the colonisation of specialised taxa such as Argilloecia sp., Cytheropteron sp., Echinocythereis sp., and Hemicytherura spp. Our results may aid in the understanding of how communities (i.e., ostracods and foraminifers) recovered after the impact of direct deposits of volcanic ash into ocean waters. The mechanisms by which disappearance and/or mortality was induced are still not clear. The release of toxic metals during the reaction of the volcanic ash with seawater, the resulting chemical alteration in the seawater, and the change in pH, together with the possible suppression of planktonic organisms, may have caused the two main extinction phases recorded by the ANTA02-NW2 core sediments.Published35OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Real time Gutenberg–Richter b-value estimation for an ongoing seismic sequence: an application to the 2022 marche offshore earthquake sequence (ML 5.7 central Italy)
No full textThis article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy.
All rights reserved.We estimate the b-value parameter of the Gutenberg–Richter law for earthquake magnitudes in
the early stage of the Costa Marchigiana (Italy) seismic sequence, starting on 2022 November
9, with an ML 5.7 event in the Adriatic sea. In particular, we estimate both the completeness
magnitude Mc and the b-value within the first 4 and 7 d after the initial strong event in the
sequence. Our work represents a practical example of b-value estimation in ‘true’ real time,
that is, during the seismic sequence, and its possible interpretation in terms of short-term
forecasting. We highlight some critical issues to consider both in estimating/intepreting the
b-value, and in evaluating the real time estimation of Mc. These issues are mainly due to
the fact that preliminary catalogues available in real time are quite different from the revised
ones, which are usually delivered after a few months. The criticalities are linked to the raw
data recorded at an early-stage, an unreliable evaluation of the Mc with statistical approaches,
the Short Term Aftershock Incompleteness entailed after the initial strong event, and the
magnitude binning. Our results show that real time estimation of the b-value can give insights
into the evolution of an ongoing seismic sequence, when attention is paid to data quality and
quantity.Published1326–13316T. Studi di pericolosità sismica e da maremotoJCR Journa
InSAR-Based Detection of Subsidence Affecting Infrastructures and Urban Areas in Emilia-Romagna Region (Italy)
No full textThe study of deformation signals associated with seismicity in alluvial plain areas is a
challenging topic that, however, is increasingly studied thanks to the great aid given by remote
sensing techniques that exploit Synthetic Aperture Radar (SAR) data. This study focuses on the
determination of the deformation field within the Emilia-Romagna Region (northern Italy), in the
area comprising Modena, Reggio Emilia, and Parma cities. SAR data acquired along both orbits
during the Sentinel-1 and Cosmo-SkyMed satellite missions were processed with the Small Baseline
Subset interferometric technique from June 2012, after the serious seismic swarm of May 2012, to
January 2022, just before the two earthquakes occurred in February 2022. The results, validated
with Global Navigation Satellite System measurements, do not highlight displacements correlated
with the seismicity but, thanks to their high spatial resolution, it was possible to discriminate areas
affected by noticeable subsidence phenomena: (i) the highly industrialized areas located north of the
municipalities of Reggio Emilia and Modena cities and (ii) a sector of the high-speed railway sited
north of the Reggio Emilia city centre, close to the Reggio Emilia AV Mediopadana station. Here we
show that, at least since 2012, the latter area is affected by subsidence which can be related to the
secondary consolidation process of the fine soils loaded by the railway embankment. The piezometric
level analysis also suggests that the lowering of the groundwater table could accelerate the subsidence
rate, affecting the stability of infrastructures in highly populated and industrialized areasPublished2076-3263OST5 Verso un nuovo MonitoraggioJCR Journa