OA Earth-prints Repository
Not a member yet
16457 research outputs found
Sort by
Detection of Subtle Thermal Anomalies: Deep Learning Applied to the ASTER Global Volcano Dataset
No full textTwenty-one years of ASTER global thermal infrared
(TIR) acquisitions provide a large amount of data for volcano
monitoring. These data, with high spatial and spectral resolution,
enable routine investigations of volcanoes in remote and
inaccessible regions, including those with no ground-based
monitoring. However, the dataset is too large to be manually
analyzed on a global basis. Here, we systematically process the
data over several volcanoes using a deep learning algorithm to
automatically extract volcanic thermal anomalies. We explore the
application of a Convolutional Neural Network (CNN), specifically
UNET, to detect subtle to intense anomalies exploiting the spatial
relationships of the volcanic features. We employ a supervised
UNET network trained with the largest (1500) labeled dataset of
ASTER TIR images from five different volcanoes, namely Etna
(Italy), Popocatépetl (Mexico), Lascar (Chile), Fuego (Guatemala),
and Kliuchevskoi (Russia). We show that our approach achieves
high accuracy (93%) with excellent generalization capabilities.
The effectiveness of our model for detecting the full range of
thermal emission is shown for volcanoes with very different styles
of activity and tested at Vulcano (Italy). The results demonstrate
the potential applicability of the proposed approach to the
development of automated thermal analysis systems at the global scale using future TIR data such as the planned NASA SBG
mission.Published5000715JCR Journa
Reconstructing tephra fall deposits via ensemble-based data assimilation techniques
No full textIn recent years, there has been a growing inter- est in ensemble approaches for modelling the atmospheric transport of volcanic aerosol, ash, and lapilli (tephra). The development of such techniques enables the exploration of novel methods for incorporating real observations into tephra dispersal models. However, traditional data assimilation al- gorithms, including ensemble Kalman filter (EnKF) meth- ods, can yield suboptimal state estimates for positive-definite variables such as those related to volcanic aerosols and tephra deposits. This study proposes two new ensemble- based data assimilation techniques for semi-positive-definite variables with highly skewed uncertainty distributions, in- cluding aerosol concentrations and tephra deposit mass load- ing: the Gaussian with non-negative constraints (GNC) and gamma inverse-gamma (GIG) methods. The proposed meth- ods are applied to reconstruct the tephra fallout deposit re- sulting from the 2015 Calbuco eruption using an ensemble of 256 runs performed with the FALL3D dispersal model. An assessment of the methodologies is conducted consider- ing two independent datasets of deposit thickness measure- ments: an assimilation dataset and a validation dataset. Dif- ferent evaluation metrics (e.g. RMSE, MBE, and SMAPE) are computed for the validation dataset, and the results are compared to two references: the ensemble prior mean and the EnKF analysis. Results show that the assimilation leads to a significant improvement over the first-guess results ob- tained from the simple ensemble forecast. The evidence from this study suggests that the GNC method was the most skilful approach and represents a promising alternative for assimila- tion of volcanic fallout data. The spatial distributions of the tephra fallout deposit thickness and volume according to the GNC analysis are in good agreement with estimations based on field measurements and isopach maps reported in previ- ous studies. On the other hand, although it is an interesting approach, the GIG method failed to improve the EnKF analysis.EUPublished3459–3478OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
Scale dependence of fractal dimension in deterministic and stochastic Lorenz-63 systems
No full text9 pages, 6 figuresMany natural systems show emergent phenomena at different scales, leading to scaling regimes with signatures of deterministic chaos at large scales and an apparently random behavior at small scales. These features are usually investigated quantitatively by studying the properties of the underlying attractor, the compact object asymptotically hosting the trajectories of the system with their invariant density in the phase space. This multi-scale nature of natural systems makes it practically impossible to get a clear picture of the attracting set. Indeed, it spans over a wide range of spatial scales and may even change in time due to non-stationary forcing. Here, we combine an adaptive decomposition method with extreme value theory to study the properties of the instantaneous scale-dependent dimension, which has been recently introduced to characterize such temporal and spatial scale-dependent attractors in turbulence and astrophysics. To provide a quantitative analysis of the properties of this metric, we test it on the well-known low-dimensional deterministic Lorenz-63 system perturbed with additive or multiplicative noise. We demonstrate that the properties of the invariant set depend on the scale we are focusing on and that the scale-dependent dimensions can discriminate between additive and multiplicative noise despite the fact that the two cases have exactly the same stationary invariant measure at large scales. The proposed formalism can be generally helpful to investigate the role of multi-scale fluctuations within complex systems, allowing us to deal with the problem of characterizing the role of stochastic fluctuations across a wide range of physical systems.Published023144OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Sistema di sincronizzazione dei dati multiparametrici acquisiti dagli osservatori sottomarini cablati nella facility di EMSO Western Ionian Sea
No full textIl progetto PON-EMSO InSea (Initiatives in Supporting the consolidation and enhancement of the
EMSO infrastructure and related Activities) si prefigge di potenziare l’infrastruttura sottomarina
situata a largo di Catania e denominata Western Ionian Sea, la facility gestita da INGV (Istituto
Nazionale di Geofisica e Vulcanologia) e parte del Consorzio Europeo EMSO (European
Multidisciplinary Seafloor and water column Observatory). Il progetto di potenziamento ha come
obiettivo l’installazione permanente di diversi osservatori multiparametrici di fondo del mare, ad
una profondità di circa 2000 metri, alimentati da un cavo elettro-ottico sottomarino connesso ad
una stazione di terra presente nel porto di Catania e gestita in collaborazione con l’INFN (Istituto
Nazionale di Fisica Nucleare). Attraverso il cavo elettro-ottico, la strumentazione sottomarina è
parte di una rete ethernet che ha il compito di salvare i dati prodotti dagli osservatori, monitorare
e controllare i parametri dell’infrastruttura sottomarina e gestire la temporizzazione di tutti gli
strumenti. Questo rapporto tecnico descrive le caratteristiche costruttive e funzionali della scheda
di sincronizzazione Syncboard v1.0 realizzata dall’INGV per distribuire la temporizzazione, fornita
da un’antenna GPS installata presso la stazione di terra, a tutti gli strumenti installati sugli
osservatori sottomarini.Published3-20OSA4: Ambiente marino, fascia costiera ed Oceanografia operativaN/A or not JC
Modeling the Shape and Velocity of Magmatic Intrusions, a New Numerical Approach
No full textDykes are magma-filled fractures propagating through the brittle crust. Understanding the physics of dyking process is essential to mitigate the volcanic hazard associated with the opening of new eruptive fissures at the surface. Often, physics-based models view either fracturing of the host rock or viscous flow of the magma as the dominating energy sink during dyke propagation. Here, we provide a numerical model that captures the coupling of fracturing at the crack tip and the transport of a viscous fluid. Built with the boundary element technique, our model allows for computation of the shape and velocity of a growing fluid-filled crack accounting for the viscosity of the fluid: the fluid flow induces a viscous pressure drop acting at the crack walls, and modifies the shape of the crack. The energy conservation equation provides the constraints to solve for the crack growth velocity, assuming that brittle fracturing and viscous flow are the main processes that dissipate energy. Using a parameter range that represents typical magmatic intrusions, we obtain crack shapes displaying some typical characteristics, including a tear-drop head and an open tail that depend on rock rigidity, magma viscosity, and buoyancy. We show that viscous forces significantly contribute to the energy dissipated during the propagation of magmatic dykes. Applied to the 1998 intrusion at Piton de la Fournaise (La Réunion Island), we provide ranges of dyke lengths and openings by adjusting the numerical velocity to the one deduced from the migration of volcano-tectonic events.Publishede2022JB0256972V. Struttura e sistema di alimentazione dei vulcani4V. Processi pre-eruttiviJCR Journa
Rifting‐Driven Magmatism Along the Dead Sea Continental Transform Fault
No full textThe Dead Sea Fault (DSF) is a crustal-scale continental transform fault separating the African
and the Arabian plates. Neogene to Quaternary volcanic activity is well-spread in Northern Israel. Yet, the
origin of the magmas that fed the eruptions is still unpinned. Our local earthquake tomography depicts velocity
distributions typical of rifting settings. At 9 km depth, a prominent high Vp/Vs anomaly marks the presence
of cooling melts. We propose that protracted transtension along the DSF caused crustal thinning promoting
the emplacement of magmatic bodies. Crustal emplacements of magmas in Northern Israel reconcile multiple
observations, including the high geothermal gradient, the prominent magnetic anomalies and the traces of
mantle-derived fluids in the springs across the Sea of Galilee. We provide a compelling evidence for rifting in
segments of the DSF and identify the potential source of magmatism that fed part of the volcanic activity of the
area.Publishede2022GL099964OST3 Vicino alla fagliaJCR Journa
Geomorphology of the upper sector of the Roncovetro active landslide (Emilia-Romagna Region, Italy)
No full textWe present the geomorphological map of the upper sector of the Roncovetro active landslide (Enza Valley, Emilia-Romagna, Italy). The 1:1500 scale map provides an accurate picture of the landslide in October 2014. The map is mainly based on the data collected during an airborne LiDAR survey. The capability of LiDAR to ‘penetrate’ the vegetation cover makes these data the most complete and accurate topographic dataset of this landslide. The map shows that the upper sector of the Roncovetro landslide consists of gravity- and water runoff-related forms. Gravitational features are linked to sliding and flowing movements that characterize the short- and long-term behaviour of the landslide. By comparing the 2014 LiDAR-Digital Elevation Model (DEM) with the 1973 DEM provided by the Emilia-Romagna Region, we calculated that 6.2 ± 0.8 × 105 m3 of material has moved from the top of the Roncovetro landslide in about 40 years.Published2277898OST2 Deformazione e Hazard sismico e da maremotoOST5 Verso un nuovo MonitoraggioOSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Forecasted weakening of Atlantic overturning circulation could amplify future relative sea-level rise in the Mediterranean: A review of climate and tide-gauge data links
No full textSea-level rise is one of the most significant and perceptible consequences of global warming because it affects natural environments and coastal anthroposcapes at human timescales, particularly in sediment-starved littoral contexts. Within this framework, improvements in understanding the projection of sea-level rise require better knowledge of regional changes. Here we focus on the recent sea-level history of the Mediterranean Sea, an area characterized by a densely populated coast and where climate variability is larger, and the rate of sea-level rise higher than the global average. We produce a spatially-averaged Mediterranean relative sea-level (RSL) time series, based on 138 tide-gauge records, stretching back to the late 1800s, indicating that Mediterranean RSL has risen by ∼24 cm in the past ∼140 years. At interdecadal timescales and beyond, we find that Mediterranean relative sea-level rising rates (RSLRR) are significantly influenced by the strength of the Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC). Climate-model predictions of a weakened Atlantic overturning circulation in the coming decades, slowing and diminishing North Atlantic heat transport, has the potential to accentuate Mediterranean rising rates, with significant implications for the basin's coastal societies, infrastructure and economies. We conservatively estimate that a 0.1 °C decrease in AMO sea surface temperatures can accentuate Mediterranean RSLRR by up to −0.61 ± 0.5 mm yr−1. Future coastal management and adaptation policies must assimilate these findings into local/regional-scale impact and vulnerability assessments.Published1044564A. Oceanografia e climaJCR Journa
Fault rupture and aseismic creep accompanying the December 26, 2018, Mw 4.9 Fleri earthquake (Mt. Etna, Italy): Factors affecting the surface faulting in a volcano-tectonic environment
No full textOn December 26, 2018 (2:19 UTC), during a volcanic eruption on the Mt. Etna eastern flank (Sicily, southern
Italy), the largest instrumental earthquake ever recorded in the volcano ruptured the Fiandaca Fault, with
epicenter between Fleri and Pennisi villages (hypocenter at ca. 300 m a. s. l., Mw 4.9). This was the mainshock of
an earthquake swarm and it was accompanied by widespread surface faulting and extensive damage along a
narrow belt near the fault trace. Few hours after the mainshock, an episodic aseismic creep event occurred along
the Aci Platani Fault, a SE extension of the Fiandaca Fault, which caused several damages in the Aci Platani
village. We surveyed and mapped the coseismic and aseismic ground ruptures, and collected structural data on
their geometry, displacement, and fault zone fabric. We compared the mapped surface ruptures with topography,
lithology, and morphology of the buried top of the sedimentary basement. We conclude that the geometry of the
volcanic pile influenced the surface expression of faulting during the December 26, 2018 event. The top surface
of the marly clay basement should be considered as a detachment surface for shallow sliding blocks. The
earthquake occurred on top of a depression of the sedimentary basement forcing the sliding eastward, causing at
surface the re-arrangement of the fault strand pattern and deformation style, switching from shear faulting to a
tensile failure. The Fleri earthquake therefore provides an unprecedented dataset for 1) understanding active
faulting in the European largest onshore volcano, 2) modeling its complex dynamics, and 3) contributing to a
more refined surface faulting hazard assessment at Mt. Etna. Results from this investigation might be useful for
characterizing capable faulting in similar volcano-tectonic settings worldwide.Published25-41JCR Journa
Exceptional eruptive CO2 emissions from intra-plate alkaline magmatism in the Canary volcanic archipelago
No full textAlkaline mafic magmas forming intra-plate oceanic islands are believed to be strongly enriched in CO2 due to low-degree partial melting of enriched mantle sources. However, until
now, such CO2 enhancement has not been verified by measuring CO2 degassing during a
subaerial eruption. Here, we provide evidence of highly CO2-rich gas emissions during the
86-day 2021 Tajogaite eruption of Cumbre Vieja volcano on La Palma Island, in the Canary
archipelago. Our results reveal sustained high plume CO2/SO2 ratios, which, when combined
with SO2 fluxes, melt inclusion volatile contents and magma production rates at explosive
and effusive vents, imply a magmatic CO2 content of 4.5 ± 1.5 wt%. The amount of CO2
released during the 2021 eruptive activity was 28 ± 14 Mt CO2. Extrapolating to the volume of
alkaline mafic magmas forming La Palma alone (estimated as 4000 km3 erupted over 11 Ma),
we infer a maximum CO2 emission into the ocean and atmosphere of 1016 moles of CO2,
equivalent to 20% of the eruptive CO2 emissions from a large igneous province eruption,
suggesting that the formation of the Canary volcanic archipelago produced a CO2 emission of
similar magnitude as a large igneous province.Published467OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa