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  • 1
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    The noble gas signature of the 2021 Tajogaite eruption (La Palma, Canary Islands) (2024)
    Elsevier
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    Publikationsdatum: 2024-05-06
    Beschreibung: Here, we characterize the temporal evolution of volatiles during the Tajogaite eruption by analyzing the elemental (He-Ar-CO2-N2) and isotopic (He-Ar-Ne) composition of fluid inclusions (FI) in phenocrysts (olivine+ pyroxene) identified in erupted lavas. Our 2021 lava samples identify substantial temporal variations in volatile composition. We show that, during the 2021 Tajogaite eruption, the He-CO2-N2 concentrations in FI increased since October 15th; this increase was accompanied by increasing 40Ar/36Ar ratios (from ~300 to 〉500), and paralleled a major shift in bulk lava chemistry, with increasing Mg contents (Mg#, from 47 to 52 to 55–59), CaO/Al2O3 (from 0.65 to 0.74 to 0.75–0.90), Ni and Cr, and decreasing TiO2, P2O5 and incompatible elements. The olivine core composition also became more forsteritic (from Mg# = 80–81 to Mg# = 84–86). Mineral thermobarometry and FI barometry results indicate that the eruption was sustained by magmas previously stored in at least two magma accumulation zones, at respectively ~6–12 km and 15–30 km, corroborating previous seismic and FI evidence. We therefore propose that the compositional changes seen throughout the eruption can be explained by an increased contribution - since early/mid-October - of more primitive, less degassed magma from the deeper (mantle) reservoir. Conversely, Rc/Ra values (3He/4He ratios corrected for atmospheric contamination) remained constant throughout the whole eruption at MORB-like values (7.38 ± 0.22 Ra, 1σ), suggesting an isotopically homogeneous magma feeding source. The Tajogaite He isotope signature is within the range of values observed for the 1677 San Antonio lavas (7.37 ± 0.17Ra, 1σ), but is more radiogenic than the 3He/4He values (〉9 Rc/Ra) observed in the Caldera de Taburiente to the north. The 3He/4He ratios (6.75 ± 0.20 Ra, 1σ) measured in mantle xenoliths from the San Antonio volcano indicate a relatively radiogenic nature of the mantle beneath the Cumbre Vieja ridge. Based on these results and mixing modeling calculations, we propose that the homogeneous He isotopic signatures observed in volatiles from the Tajogaite/San Antonio lavas reflect three component mixing between a MORB-like source, a radiogenic component and small additions (6–15%) of a high 3He/4He reservoir-derived (〉9Ra) fluid components. The simultaneous occurrence of high 3He/4He (〉9Ra)- and MORB-like He signatures in northern and southern La Palma is interpreted to reflect small-scale heterogeneities in the local mantle, arising from spatially variable proportions of MORB, radiogenic, and high 3He/4He components.
    Beschreibung: Published
    Beschreibung: 107928
    Beschreibung: OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici
    Beschreibung: JCR Journal
    Schlagwort(e): La Palma ; 2021 Tajogaite eruption ; Fluid inclusions ; Noble gas ; Magma feeding system ; Mantle source heterogeneity ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
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    The structure of sedimentary basins of Antarctica and a new three-layer sediment model (2024)
    Elsevier
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    Publikationsdatum: 2024-04-05
    Beschreibung: We use geophysical data together with a recent subglacial bedrock map (BEDMACHINE model) to obtain and investigate a new three-layer sediment model for Antarctica that locally improves the global sediment model. We provide a combined, continuous, sediment model for Antarctica and surrounding oceans by joining such improved continental sedimentary model with an existing global one (GlobSed). Our results reveal large differences between sedimentary basins for Antarctica due to their age and origin. The maximum thickness of sediments is reached under Filchner-Ronne Ice Shelf and off the Weddell Sea coast (10–12 km); further offshore, towards the ocean, the thickness of sediments drops to 4–5 km. We divide the sediment cover into three layers to distinguish material with different velocities. The lower sediment layer (deeper than 7 km) with high P-wave velocities (4.0–4.9 km/s) is found only for Lambert Rift and Filchner-Ronne basin. The middle layer (2–7 km) has large variations for different sedimentary basins: 3.5–3.7 km/s for Lambert Basin; 4.0–4.3 km/s for Ross, Byrd and Bentley basins; 3.3–4.0 km/s for Filchner-Ronne Basin. The upper sediment layer (0–2 km) has large velocity variations, from 2.0 km/s for Ross and Lambert basins (young sediments) to 4.7 km/s for Dronning Maud Land basins. We suggest that P-wave velocities larger than 4 km/s represent old, compacted sediments which belong to the Beacon Supergroup; about 3 km/s refer to Mesozoic (rifted?) sediments; and less than 3 km/s relate to young Cenozoic sediments. According to this criterion, Dronning Maud Land, Bentley and Byrd basins belong to the Beacon Supergroup, while more complex and thicker Ross, Lambert and Filchner-Ronne basins contain sediments from Beacon Supergroup in the middle or lower layer, respectively. Other sedimentary basins with more moderate velocities possibly belong to the East Antarctic Rift System which formed later during Gondwana breakup.
    Beschreibung: Published
    Beschreibung: 229662
    Beschreibung: OST1 Alla ricerca dei Motori Geodinamici
    Beschreibung: JCR Journal
    Schlagwort(e): 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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    Low-cost MEMS accelerometers for earthquake early warning systems: A dataset collected during seismic events in central Italy (2024)
    Elsevier
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    Publikationsdatum: 2024-03-13
    Beschreibung: This article describes a dataset of acceleration signals acquired from a low-cost Wireless Sensor Network (WSN) during seismic events that occurred in Central Italy. The WSN consists of 5 low-cost sensor nodes, each embedding an ADXL355 tri-axial MEMS accelerometer with a fixed sampling frequency of 250 Hz. The data was acquired from February 2023 to the end of June 2023. During this period, several earthquake sequences affected the area where the sensor network was installed. Continuous data was acquired from the WSN and then trimmed around the origin time of seismic events that occurred near the installation site, close to the city of Pollenza (MC), Italy. A total of 67 events were selected, whose data is available at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) Seismology data center. The traces acquired from the WSN were then manually annotated by analysts from INGV. Annotations include picking time for P and S phases, when distinguishable from the background noise, alongside an associated uncertainty level for the manual annotations. The resulting dataset consists of 328 3 × 25,001 arrays, each associated with its metadata. The metadata includes event data (hypocenter position, origin time, magnitude, magnitude type, etc.), trace-related data (mean, median, maximum, and minimum amplitudes, manual picks, and picks uncertainty), and sensor-specific data (sensor name, sensitivity, and orientation). Furthermore, a small dataset consisting of non-seismic traces is included, with the goal of providing records of noise-only traces, relative to both electronic and environmental/anthropic noise sources. The dataset holds potential for training and developing Machine Learning or signal processing algorithms for seismic data with low signal-to-noise ratios. Additionally, it is valuable for research about earthquakes, structural health monitoring, and MEMS accelerometer performance in civil and seismic engineering applications.
    Beschreibung: Published
    Beschreibung: 110174
    Beschreibung: OST5 Verso un nuovo Monitoraggio
    Beschreibung: JCR Journal
    Schlagwort(e): Earthquake early warning; Internet of things; MEMS accelerometers; Structural health monitoring; Wireless sensor network ; 05.04. Instrumentation and techniques of general interest ; 05.02. Data dissemination ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    The micro‐seismicity of Co. Donegal (Ireland): Defining baseline seismicity in a region of slow lithospheric deformation (2024)
    Wiley
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    Publikationsdatum: 2024-02-07
    Beschreibung: A catalogue of precisely located micro-seismicity is fundamental for investigating seismicity and rock physical properties in active tectonic and volcanic regions and for the definition of a ‘baseline’ seismicity, required for a safe future exploitation of georesource areas. In this study, we produce the first manually revised catalogue of micro-seismicity for Co. Donegal region (Ireland), an area of about 50K M2 of on-going deformation, aimed at localizing natural micro-seismic events occurred between 2012 and 2015. We develop a stochastic method based on a Markov chain Monte Carlo (McMC) sampling approach to compute earthquake hypocentral location parameters. Our results indicates that micro-seismicity is present with magnitudes lower than 2 (the highest magnitude is 2.8).The recorded seismicity is almost clustered along previously mapped NE-SW trending, steeply dipping faults and confined within the upper crust (focal depth less than 10 km). We also recorded anthropogenic seismicity mostly related to quarries' activity in the study area.
    Beschreibung: Published
    Beschreibung: 62-76
    Beschreibung: OST1 Alla ricerca dei Motori Geodinamici
    Beschreibung: JCR Journal
    Schlagwort(e): 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    Nature and origin of an undetected seismic phase in waveforms from Southern Tyrrhenian (Italy) intermediate-depth and deep earthquakes: First evidence for the phase-A in the subducted Uppermost Lithospheric Mantle? (2024)
    Elsevier
    Details
    Publikationsdatum: 2024-01-17
    Beschreibung: We have found a previously unreported later seismic phase in seismograms of European seismic stations from intermediate-depth and deep earthquakes of the Southern Tyrrhenian subduction zone. We observe this phase at stations from 6 to 9◦ from the epicentre, towards north. Only seismograms of earthquakes located in a welldefined region of the slab, in the depth range of 215–320 km, show the later x-phase. In this work, we describe the nature and possible origin of this phase, and we provide a simple 2D model to explain the observed arrival times. Our analyses reveal that the x-phase propagates downward in a high velocity layer, possibly located within the deepest part of the slab. We suggest that this layer reveals the presence of the dense hydrous magnesium silicate phase A, introduced from petrological laboratory experiments, inferred to carry water in the upper mantle and predicted to be found in cold subduction zones.
    Beschreibung: Published
    Beschreibung: 229919
    Beschreibung: OST1 Alla ricerca dei Motori Geodinamici
    Beschreibung: JCR Journal
    Schlagwort(e): Southern Tyrrhenian subduction zone ; Mineral phase A ; Intermediate and deep seismicity ; Waveforms analyses ; Later seismic arrival/phase ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Regulation of deep carbon degassing by gas-rock-water interactions in a seismic region of Southern Italy (2024)
    Elsevier
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    Publikationsdatum: 2024-01-08
    Beschreibung: This study is focused on fluids characterization and circulations through the crust of the Irpinia region, an active seismic zone in Southern Italy, that has experienced several high-magnitude earthquakes, including a catastrophic one in 1980 (M = 6.9 Ms). Using isotopic geochemistry and the carbon‑helium system in free and dissolved volatiles in water, this study aims to explore the processes at depth that can alter pristine chemistry of these natural fluids. Gas-rock-water interactions and their impact on CO2 emissions and isotopic composition are evaluated using a multidisciplinary model that integrates geochemistry and regional geological data. By analyzing the He isotopic signature in the natural fluids, the release of mantle-derived He on a regional scale in Southern Italy is verified, along with significant emissions of deep-sourced CO2. The proposed model, supported by geological and geophysical constraints, is based on the interactions between gas, rock, and water within the crust and the degassing of deep-sourced CO2. Furthermore, this study reveals that the Total Dissolved Inorganic Carbon (TDIC) in cold waters results from mixing between a shallow and a deeper carbon endmember that is equilibrated with carbonate lithology. In addition, the geochemical signature of TDIC in thermal carbon-rich water is explained by supplementary secondary processes, including equilibrium fractionation between solid, gas, and aqueous phases, as well as sinks such as mineral precipitation and CO2 degassing. These findings have important implications for developing effective monitoring strategies for crustal fluids in different geological contexts and highlight the critical need to understand gas-water-rock interaction processes that control fluid chemistry at depths that can affect the assessment of the CO2 flux in atmosphere. Finally, this study highlights that the emissions of natural CO2 from the seismically active Irpinia area are up to 4.08·10+9 mol·y-1, which amounts is in the range of worldwide volcanic systems.
    Beschreibung: Published
    Beschreibung: 165367
    Beschreibung: OST3 Vicino alla faglia
    Beschreibung: OST5 Verso un nuovo Monitoraggio
    Beschreibung: JCR Journal
    Schlagwort(e): CO(2) output; Carbon isotopes; Degassing; Earthquakes; Noble gases; Precipitation ; 04.04 Solid Earth ; 01.01. Atmosphere ; 03.01. General ; 03.02. Hydrology ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Investigation of the Norcia basin (Central Italy) through ambient vibration measurements and geological surveys (2021)
    Elsevier
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    Publikationsdatum: 2023-11-21
    Beschreibung: During the 2016–2017, a seismic sequence struck the Central Italy, involving four regions (Umbria, Marche, Abruzzo and Lazio) and causing important damages and victims in inhabited areas such as Norcia and Amatrice towns. The strongest event of the seismic sequence was a Mw 6.5 event with epicenter at about 5 km far from the Norcia area, which is an intermontane basin prone to ground motion amplification. The historical town of Norcia and the surrounding hamlets were recently investigated by the microzonation activity, but information on the geometry and velocity are still partial considering the entire basin. Indeed, past studies aimed at reconstructing the elastic and geometrical properties focusing mainly on the northern part of the basin. Specifically in this paper, we integrated seismic and geological data to get a better knowledge of the properties of the Quaternary Norcia basin. A geological survey was carried out to provide a geological map and three geological cross-sections. We analyzed new seismic ambient vibrations data, collected by single-seismic stations, to infer the distribution of resonant frequency (f0) for the entire basin. We used passive arrays of seismic stations to better define the velocity profiles of the area. In the northern part of the basin, two 2D arrays with elliptical-like shapes were deployed showing strong discrepancies of the elastic soil properties in proximity of Norcia town. We found shear-wave velocities of the near-surface profile of about 300–400 and 500–800 m/s in presence of palustrine and alluvial fan deposits, respectively. Further, the values of f0 are abruptly varying from 0.5 Hz in the SW sector of Norcia village up to 2 Hz in its NE sector. Ambient vibration data reveal less pronounced variation of f0 in the southern part of the basin, with resonant values that are almost in the range 1–1.3 Hz. In the southern sector, a 1D array was arranged along a 5-km line and was analyzed by means of seismic noise cross-correlation analysis suggesting the presence of a deeper seismic contrast. The integration of geophysical and geological results has allowed to infer insights on the subsurface geometry of the basin.
    Beschreibung: Published
    Beschreibung: 105501
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: JCR Journal
    Schlagwort(e): 04.02. Exploration geophysics ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Noble gas magmatic signature of the Andean Northern Volcanic Zone from fluid inclusions in minerals (2020)
    Elsevier
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    Publikationsdatum: 2023-11-21
    Beschreibung: Trace volatile elements like He are key for understanding the mantle source signature of magmas and to better constrain the relative roles of subduction and crustal processes to the variability of along-arc chemical and isotopic signatures of magmatic fluids. Here we report on noble gas abundances and isotopic data of Fluid Inclusions (FIs) in eruptive products and/or fumarolic gases from the Colombia-Ecuador segment of Andean Northern Volcanic Zone (NVZ). FIs in olivine phenocrysts from Ecuador (El Reventador, Cotopaxi and Tungurahua) yield air-normalized corrected 3He/4He ratios of 7.0–7.4 RA, within the MORB range (8 ± 1 RA). With exception of the Cotopaxi lavas (opx 〈 〈oliv.), these are indistinguishable of those obtained for their cogenetic orthopyroxene pairs and of gas emissions previously reported in literature. Olivine phenocrysts from Nevado del Ruiz fissure lavas also yield the highest 3He/4He (8.5 ± 0.3 RA) for this volcanic system, which is in the range of fumarolic gases for Galeras (previously reported as high as 8.8 RA and here measured to a maximum of 8.3 ± 0.1 RA). Our dataset highlights disparities between isotope signatures of eruptive products from Ecuador (avg. ~7.2 RA) and those reported for the Colombian portion of the NVZ (avg. ~8.5 RA). Previous studies on the geochemistry of erupted products put in evidence significant along-arc variations ascribed either to the involvement of different slab components, or to variable depths of evolution of arc magmas within the continental crust. However, the same variation is not discernible in the signature of noble gases, especially helium, from FIs and gas emissions analyzed in this study, with little inter-variation between Cotopaxi, Reventador and Tungurahua (all within 0.2 RA from the Ecuador average of 7.2) and Galeras and Nevado del Ruiz, whose maximum values differ by ~0.3 RA. We therefore suggest a homogenous MORB-like 3He/4He signature for the mantle wedge beneath this arc segment, whereby along-arc variations in crustal thickness (from 〈35 km at the northernmost part of the segment to ≥50 km at the Ecuadorian arc segment) may factor largely into the variability recorded on our data set. The first CO2/3He ratios obtained in FIs from Andean rocks support the hypothesis of increasing crustal contamination from Colombia to Ecuador, concomitant with increasing crustal thicknesses under the respective arc regions.
    Beschreibung: Published
    Beschreibung: 119966
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani
    Beschreibung: 4V. Processi pre-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): Andean Volcanic Belt ; Northern Volcanic Zone ; Fluid inclusions ; Noble gases ; Helium ; Crustal thickness ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Petrological and noble gas features of Lascar and Lastarria volcanoes (Chile): Inferences on plumbing systems and mantle characteristics (2020)
    Elsevier
    Details
    Publikationsdatum: 2023-11-16
    Beschreibung: Lascar (5592 m a.s.l.) and Lastarria (5697 m a.s.l.) are Chilean active stratovolcanoes located in the Central Volcanic Zone (CVZ; 16°S to 28°S) that have developed on top of a 71 km thick continental crust. Independently of the similarities in their Plinian/Vulcanian eruptive styles, their complex magmatic feeding structures and the origins of their magmatic fluids still necessitate constraints in order to improve the reliability of geochemical monitoring. Here we investigate the petrography, bulk-rock chemistry, and mineral chemistry in products from the 1986–1993 explosive eruptive cycle at Lascar and from several Holocene eruptive sequences at Lastarria. These data are integratedwith measurements of the noble gas isotopes in fluid inclusions (FIs) of minerals fromthe same products as well as in fumarole gases. The geochemistry ofminerals and rocks shows that the studied products belong to high-K–calc-alkaline series typical of subduction-related settings, and provide evidence of differentiation,mixing, and crustal assimilation that are higher at Lastarria. The contribution of slab sediments and fluids to magma genesis in thewedge is limited, suggesting a homogeneous mantle beneath CVZ. The deepest crystallization processes occurred at variable levels of the plumbing systems according to the lithostatic equivalent depths estimated with mineral equilibrium geobarometers at Lascar (15–29 km) and Lastarria (~20–40 km). The 40Ar/36Ar and 4He/20Ne ratios in FIs and fumarole gases indicate the presence of some degree of air contamination in the fluids from both volcanoes. The 3He/4He values at Lascar (6.9–7.3 Ra) are relatively homogeneous and comparable to those of fumaroles, suggesting a main zone of magma crystallization and degassing. In contrast, the 3He/4He values at Lastarria (5.31–8.01 Ra) vary over a wide range, suggesting various magma storage levels and providing evidence of crustal contamination, as indicated by the rock chemistry.We argue thatmantle beneath the two volcanoes has a MORB-like signature of 3He/4He, while local crustal contamination explains the lower ratios measured at Lascar.
    Beschreibung: Published
    Beschreibung: 105615
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani
    Beschreibung: JCR Journal
    Schlagwort(e): Lascar ; Lastarria ; noble gases ; Fluid inclusions ; Crustal contamination ; Mantle wedge ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    The composition of fluids stored in the central Mexican lithospheric mantle: Inferences from noble gases and CO2 in mantle xenoliths (2021)
    Elsevier
    Details
    Publikationsdatum: 2023-11-16
    Beschreibung: We present the first isotopic (noble gases and CO2) characterization of fluid inclusions coupled to Raman microspectroscopy analyses in mantle xenoliths from Central Mexico, a geodynamically complex area where the Basin and Range extension was superimposed on the Farallon subduction (terminated at 28 Ma). To characterize the isotopic signature of the Central Mexican lithospheric mantle, we focus on fluid inclusions entrapped in mantle xenoliths found in deposits of the Joya Honda maar (JH), a Quaternary monogenetic volcano belonging to the Ventura Espiritu Santo Volcanic Field (VESVF) in the state of San Luis Potosí (central Mexico). Thirteen ultramafic plagioclase-free xenoliths were selected, all exhibiting a paragenesis Ol 〉 Opx 〉 Cpx 〉 〉 Sp, and being classified as spinel-lherzolites and harzburgites. All xenoliths bring textural evidence of interstitial glass veins bearing dendritic trails of secondary melt and fluid inclusions (composed of silicate glass ± CO2 ± Mg-Ca carbonates ± pyrite). These are related to pervasive mantle metasomatism driven by carbonate-rich silicate melt. The Ar and Ne systematics reflect mixing between MORB-like upper mantle and atmospheric fluids, the latter interpreted as reflecting a recycled air component possibly inherited from the Farallon plate subduction. The 3He/4He ratios vary between 7.13 and 7.68 Ra, within the MORB range (7–9 Ra), and the 4He/40Ar* ratios (0.4–3.11) are similarly close to the expected range of the fertile mantle (1–5). Taken together, these pieces of evidence suggest that (i) either the mantle He budget was scarcely modified by the Farallon plate subduction, and/or (ii) that any (large) crustal contribution was masked by a later metasomatism/refertilization episode, possibly during the subsequent Basin and Range extension. A silicate melt-driven metasomatism/refertilization (revealed by the association between glass veins and fluid inclusions) is consistent with calculated helium residence time for the Mexican lithospheric mantle (20 to 60 Ma) that overlaps the timing of the above geodynamic events. We propose that, after the refertilization event (e.g., over the last ~20 Ma), the lithospheric mantle has evolved in a steady-state, becoming slightly more radiogenic. We also estimated 3He fluxes (0.027–0.080 mol/g), 4He production rates (340–1000 mol/yr), and mantle CO2 fluxes (3.93 × 107 mol/yr to 1.18 × 108 mol/yr) using the helium isotopic values measured in JH mantle xenoliths. Finally, the JH xenoliths exhibit CO2/3He ratios comparable to those of the upper mantle (from 3.38 × 108 to 3.82 × 109) but more positive δ13C values (between - 1.0 and - 2.7‰), supporting the involvement of a crustal carbonate component. We propose that the metasomatic silicate melts recycled a crustal carbonate component, inherited by the Farallon plate subduction.
    Beschreibung: Published
    Beschreibung: 120270
    Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani
    Beschreibung: JCR Journal
    Schlagwort(e): Mexican mantle xenoliths ; Fluid inclusions ; Noble gases ; CO2 ; mantle refertilization ; Carbonate recycling ; 04.01. Earth Interior ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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