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ClimaMeter: Contextualising Extreme Weather in a Changing Climate
No full textClimate change is a global challenge with multiple far-reaching consequences, including the intensification and increased frequency of many extreme weather events. In response to this pressing issue, we present ClimaMeter, a platform designed to assess and contextualise extreme weather events relative to climate change. The platform offers near real-time insights into the dynamics of extreme events, serving as a resource for researchers, policymakers, and being a science dissemination tool for the general public. ClimaMeter currently analyses heatwaves, cold spells, heavy precipitation and windstorms. This paper elucidates the methodology, data sources, and analytical techniques on which ClimaMeter relies, providing a comprehensive overview of its scientific foundation. To illustrate Climameter, we provide four examples, the December 2022 North American Winter Storm, the August 2023 Guangdong – Hong Kong Flood, the late 2023 French Heatwave and the July 2023 windstorm Poly. They underscore the role of ClimaMeter in fostering a deeper understanding of the complex interactions between climate change and extreme weather, with the hope of ultimately contributing to informed decision-making and climate resilience.Published959–983OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Dual-proxy estimation of Vs30: the case study of the Marche Region (central Italy)
No full textThis study focuses on generating a shear-wave velocity averaged within the uppermost 30 m ofthe ground surface (Vs30) map for the Marche region (central Italy) using two commonlyacknowledged proxies: topographic slope and lithological classification. The analysis isbased on a comprehensive dataset of geophysical tests from the Italian seismicmicrozonation dataset, employed as a training set. Through regression analysis, Vs30 valuesare modelled as a function of lithology and topographic slope, with a random effectaccounting for the combination of these variables. The resulting Vs30 raster map illustratesthe spatial distribution of shear-wave velocities across the region, offering a representationof the subsurface seismic characteristics essential for various applications, including localseismic hazard assessment, prediction of seismic ground motion parameters, microzonationmapping, real-time shakemap generation, and seismic design of engineering structures.Published2349787OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
CO2‐Rich Xenoliths at Mt. Vulture Volcano (Southern Italy): New Constraints on the Volcano Plumbing System
No full textThis study provides new mineral chemistry data together with micro-thermometric measurements on fluid inclusions hosted
in ultramafic xenoliths (lherzolite, wehrlite, and dunite) brought to the surface by the last Mt. Vulture volcano activity (140 ka;
southern Italy), and fed by melilitite-carbonatite magmas.
Petrographic evidence and mineralogical compositions of Mt. Vulture xenoliths are consistent with an origin in the upper mantle.
Fluid inclusions in rock-forming minerals of lherzolite and wehrlite xenoliths are CO2-dominated.
The equilibrium temperature calculated by geothermometric estimates ranges from 1039 C
(±36°C) to 1142°C (±15°C), and entrapment pressures of fluid inclusions with post-trapping
re-equilibration
correspond to the
local crust–mantle boundary (32 km depth), and to a shallow reservoir located at 12–14 km depth. These results contribute to
constrain the origin of these xenoliths and the depth of storage of magmas erupted from Mt. Vulture, where carbonatite-like
metasomatism and mantle-derived CO2 degassing occur.In pressJCR Journa
New volcanological, 40 Ar/ 39 Ar dating and paleomagnetic record from Trindade Island and stratigraphic implications
No full textUnrevealing the stratigraphy of volcanic systems is fundamental to understanding their eruptive history and requires a multiproxy approach for the accurate correlation and interpretation of deposits. We present new volcanological, 40 Ar/ 39 Ar ages and paleomagnetic data from the volcanic rocks of Trindade Island, located at ~1.260 km from the Brazilian coast in the South Atlantic Ocean. The reconstruction of the volcanic history of Trindade Island is important because it is the youngest volcanic terrain in Brazil and part of a submarine chain that represents the most recent plume-induced alkaline manifestation beneath the South American plate. Our results suggest Trindade Island underwent two main phases of volcanism. The first phase (3.9-1.5 Ma) formed the Trindade Complex and Desejado Formation, with eruptive styles ranging from phreatomagmatic/Surtseyan to Vulcanian and of dominant phonolitic composition. The second phase (1.0-0.06 Ma) formed the nephelinitic monogenetic centers Morro Vermelho, Valado and Paredão Volcano Formations through dominant Hawaiian and Strombolian styles. The new ages imply a revised stratigraphy for the youngest units of Trindade Island, with partial overlap between them. The revised chronology integrated to the paleomagnetic directional data evidence that Trindade Complex formed during Gauss normal chron (D = 355.4 • ; I = − 49.6 •), Valado and Paredão Volcano during Brunhes normal chron (D = 14 • ; I = − 42.3 • and D = 9.2 • ; I = − 35.2 • , respectively), while Morro Vermelho records the late Matuyama-early Brunhes chron (D = 36.5 • ; I = − 19.8 •), with site-level mean paleodirections of normal and transitional polarity within the reverse Matuyama interval.Published101518OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioOSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
The 23–24 March 2021 lava fountain at Mt Etna, Italy
No full textIn 2021, more than 50 paroxysmal episodes occurred at the South-East Crater (SEC) of Mt Etna, Italy. The 23–24 March lava fountain was one of the longest episodes and began with weak Strombolian explosions, gradually transitioning to lava fountaining. The eruption intensity then dropped more slowly than in previous episodes, resulting in pulsating Strombolian explosions dominated by ash emission. Thirty-four tephra samples were used to reconstruct the fallout dispersal and estimate the total erupted mass. Grain size, textural, petrological and geochemical analyses indicate different features and were compared with the gas phase (
SO2 and HCl) in the volcanic plume. By applying stochastic global optimization to simulations of the temporal evolution of the eruption column height and tephra dispersal and deposition, the total erupted mass retrieved
(6.76 × 108 kg) matches well the total erupted mass estimation by the ground-based deposit (8.03 ± 2.38 × 108
kg), reducing the column height throughout the episode from 6.44 to 4.5 km above sea level and resulting in a mass eruption rate ranging from 1.96 × 105 to 8.18 × 103 kg/s. The unusual duration of the March episode and the characteristics of the erupted products point to the change in explosive style and magma fragmentation from fountaining to ash emission phases, associated with a slower magma supply inducing a change in magma rheology and a final, prolonged ash generation. Furthermore, this study showed that using observational data and the variation in eruption source parameters for numerical simulations can improve the accuracy of predicting the dispersal plume, thus mitigating the potential impact of longer paroxysmal episodes.Published56OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
On estimating the phase scintillation index using TEC provided by ISM and IGS professional GNSS receivers and machine learning
No full textAmplitude and phase scintillation indexes (S4 and SigmaPhi) provided by Ionospheric Scintillation Monitoring (ISM) receivers are the most used GNSS-based indicators of the signal fluctuations induced by the presence of ionospheric irregularities. These indexes are available only from ISM receivers which are not as abundant as other types of professional GNSS receivers, resulting in limited geographic distribution. This makes the scintillation indexes measurements rare and sparse compared to other types of ionospheric measurements available from GNSS receivers. Total Electron Content (TEC), on the other hand, is an ionospheric parameter available from a wide range of multi-frequency GNSS receivers. Many efforts have worked on establishing scintillation indicators based on TEC, and geodetic receivers in general, introducing various metrics, including the Rate of TEC change (ROT) and ROT Index (ROTI). However, a possible relationship between TEC and its variation, and the corresponding scintillation index that an Ionospheric Scintillation Monitor (ISM) receiver would estimate is not trivial. In principle, TEC can be retrieved from carrier phase measurements of the GNSS receiver, as
. We investigate how to estimate SigmaPhi from time series of TEC and ROT measurements from an ISM in Ny-Ålesund (Svalbard) using Machine Learning (ML). To evaluate its usability to estimate SigmaPhi
from geodetic receivers, the model is tested using TEC data provided by a quasi-co-located geodetic receiver belonging to the International GNSS Service (IGS) network. It is shown that the model performance when TEC from the IGS receiver is used gives comparable results to the model performance when TEC from the ISM receiver is utilised. The model's ability to infer the exact value of the scintillation index is bound to Mean Square Error (MSE) = 0.1 radians^2 when SigmaPhi 0. 8 radians the MSE reaches 0.18 and 0.45 radians^2 in operative testing using ISM and IGS measurements, respectively. However, the model’s ability to detect phase scintillation from IGS TEC measurements is comparable to expert visual inspection. Such a model has potential in alerting against phase fluctuations resulting in enhanced SigmaPhi, especially in locations where ISM receivers are not available, but other types of dual-frequency GNSS receivers are present.Published3753-3771OSA3: Climatologia e meteorologia spazialeJCR Journa
Splitting intensity tomography to image depth-dependent seismic anisotropy patterns beneath the Italian Peninsula and surrounding regions
No full textThe region between central Europe and the centre of the Mediterranean is characterised by complex tectonics and kinematics. Here, the interaction between thickened crust, subducting lithosphere and surrounding asthenosphere produces strong and pervasive anisotropy in the upper mantle. Shear wave splitting measurements, the most adopted method to image seismic anisotropy so far, when interpreted in a ray-based framework result in little or no depth resolution, hampering a correct image of the anisotropy distribution with depth. In this study, we aim to better constrain the depth-dependent seismic anisotropy beneath Italy and surrounding regions, by isolating for the first time the source region of anisotropy at different depths. To do that, we perform an anisotropy tomography, adopting the splitting intensity inversion method. It is entirely based on the finitefrequency effect in the splitting of SKS waves. We first computed the splitting intensity using SKS waves recorded at all available permanent and temporary stations over the region, obtaining a huge dataset of measurements used as an input for the tomographic inversion. The large-scale 3D model of seismic anisotropy obtained with the inversion shows a clear change of anisotropy properties in terms of fast polarisation direction and intensity for different depths, thus improving the characterization of the main sources of anisotropy in the mantle as a function of depth. Shallower layers (70-100 km depth) are characterised by a complex and variable oriented pattern of anisotropy fast direction and intensity, which becomes progressively more organised with depth (100-300 km). This pattern suggests a strong control exerted by the geometry and motion of the different slab segments and the large-scale asthenospheric flow generated by subduction and roll-back processes. The strength of anisotropy increases with depth, with high values affecting the bulge of the Alps and Apennines chains and the southern Tyrrhenian subduction system. On the contrary, weaker anisotropy characterises the transition zone from the Apennines to Alpine domains beneath the Po plain, and both the Adriatic and European domains.Published119005JCR Journa
Thermal transient PDC behavior induced by topographic drops: A test case at Mt. St. Helens, USA
No full textTopography plays an important yet uncertain role in modulating the temporal and spatial evolution of the in- ternal structure of pyroclastic density currents (PDCs). Understanding such changes is critical to characterize PDC transport regimes and their hazard. Here we combine paleomagnetic data from PDC deposits of the 18 May 1980 Mt. St. Helens eruption with numerical outcomes to capture spatio-temporal temperature variations induced by topography. We show that emplacement temperatures along the northwest flank of the volcano are ≃ 100◦C colder than those recorded along the northeast flank in response to proximal topographic drops. We further report that such vertical drops lead to an initial transient regime where the PDC internal temperature, velocity, and concentration stratification is altered for periods of time that are proportional to the ratio between the drop height and the square root of the current thickness. The topographic control on PDC dynamics is attenuated moving away from the drops or when a stationary phase is attained. Collectively, our results highlight that topographic regions promoting the flow separation/reattachment process are associated with vigorous entrainment of ambient air in the lower portion of PDCs. Low temperature variability is observed in the absence of such topographic irregularities. Based on our findings, we propose a local sedimentation rate of ≃ 150 ± 100 mm s−1 for PDC deposits in a proximal reattachment region. This investigation demonstrates the importance of transient processes in PDC dynamics, introducing a new methodology to measure sedimentation rates, and highlighting that flow-topography feedbacks should be considered to assess hazards.Published118441OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
The helium and carbon isotopic signature of Ocean island basalts: Insights from Fogo volcano (Cape Verde archipelago)
No full textvolatiles’ abundance and origin in their mantle sources. Here, we add new piece of knowledge to our understanding
of volatile geochemistry in global OIB magmas, by presenting new noble gas (He-Ne-Ar) and carbon (C)
isotope results for olivine- and clinopyroxene-hosted FI from enclaves, lavas, tephra and volcanic gas samples
from Fogo, the only frequently active volcano at the Cape Verde archipelago (eastern Atlantic Ocean). FI,
together with crater fumaroles, constrain the Fogo 3He/4He signature at 7.14–8.44 Rc/Ra (where RC is the aircorrected
3He/4He isotope ratio, and Ra is the same ratio in air), which is within the typical MORB (Mid-
Ocean Ridge Basalt) mantle. The carbon isotopic ratio (δ13C vs. Pee Dee Belemnite) of CO2 in FI and fumaroles
range from -6.04 to -4.41 ‰. We identify systematic variations of δ13C and He/Ar* with FI entrapment pressure
(estimated from a combination of host mineral barometry and FI microthermometry), from which we develop a
model for volatile degassing in the mantle-to-crustal magma storage system. The model predicts a crustal-like
signature for carbon (δ13C of -0.4 ± 1.0 ‰) in primary melts formed by mantle melting at ~2200 MPa (~77
km) and a source He/Ar* ratio of 0.90–0.24, which are indicative of variably depleted mantle metasomatized by
carbon enriched melts/fluids from a crustal component. We also use our results to characterise regional (in the
Cape Verde and Canary archipelagos) and global trends in C and He isotope composition from OIB. From a
comparison with the few other OIB localities for which δ13C are available, we propose that a carbon enriched
crustal component could be recurrent at a global scale in OIB magmatism, although often masked by isotope
fractionation during magmatic degassing. We additionally find that, at regional scale, He isotopes in OIB scale
inversely correlate with the degree of partial melting of the mantle beneath individual islands’ (inferred from the
La/Yb ratio of erupted basalts). More widely, our results corroborate previously established global relationships
between OIB He isotopic signature, plume buoyancy flux and overlying plate velocity. In this interpretation, the
MORB-like 3He/4He (8 ± 1 Ra) at Fogo reflects a combination of (i) low to medium magma productivity, (ii)Published118930JCR Journa
Studying Past Earthquakes with Modern Techniques: Ground-Motion Simulations for the 11 January 1693 Noto Earthquake in Italy
No full textThe 1693 Noto earthquake, which struck on 11 January, is one of the Italy’s largest and most devastating earthquakes. According to the Italian Parametric Earthquake Catalogue, it reached a maximum intensity of 11 on the Mercalli–Cancani–Sieberg scale and had an estimated magnitude of M 7.3. Nevertheless, its precise location and source definition remain subjects to debate due to the complexity of the seismic sequence and lack of geological evidence. A series of potential seismic sources differing in location, dimension, and kinematics have been proposed in the literature based on seismotec- tonic data and interpretations. The goal of this work is to perform a retrospective experiment to verify which of the proposed seismic sources have a better fit with the observed intensity data. To do so, novel simulation techniques are used to study this historical earthquake. We generated ground-motion scenarios for each proposed source model through a stochastic finite-fault simulation approach. Then, the simulated ground-motion parameters were converted to intensities using two different ground- motion intensity conversion equations for Italy. Finally, we compared these converted intensities with the observed intensity data in terms of normalized root mean square errors and converted intensities from ground-motion models. Our results generally show good consistency between converted intensities from the simulated and pre- dicted ground motions, whereas the observed intensities fit better to converted ones from the peak ground velocity rather than peak ground acceleration. Our analysis reveals that the source model reproducing the best of the macroseismic data of the Noto earthquake is the Canicattì–Villasmundo fault system with a magnitude of 7.1.Published3387–3405JCR Journa