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  • Elsevier  (317,437)
  • American Geophysical Union  (20,739)
  • 2020-2023  (610)
  • 1980-1984  (209,600)
  • 1970-1974  (124,428)
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  • 1
    Publication Date: 2022-12-22
    Description: This chapter aims at introducing the reader to general concepts about the main forcings of the Mediterranean Sea, in terms of exchanges through the Strait of Gibraltar, and air-sea exchanges of heat, freshwater, and momentum. These forcings are also responsible for the peculiar characteristics of Mediterranean water masses. Therefore, the chapter continues with giving a general explanation on water mass analysis, and then it describes the properties and vertical and horizontal distributions of the main Mediterranean water masses. To conclude, the reader is introduced to the use of other (biogeochemical, and chemical) tracers of water masses, with a focus on the Mediterranean Sea.
    Type: Book chapter , PeerReviewed
    Format: text
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  • 2
    Publication Date: 2022-04-01
    Description: Volcanic hazard assessment relies on the accurate knowledge of the eruptive style and recurrence of volcanic eruptions in the past. At El Hierro (Canary Islands) historical and prehistorical records are still poorly defined, and although the island was the location of one of the most recent eruptions (La Restinga, 2011 CE) of the Canarian archipelago, the recent subaerial volcanism is still poorly studied. Information about the age of Holocene volcanic activity as well as the stratigraphy of the deposits is scarce: few eruptions are dated so far, whereas the others are classified as pre-or Holocene events considering lava flow characteristics along the coast. Here, we report on the dating of eleven (M˜na Chamuscada, M˜na del Tesoro, Orchilla, Las Calcosas, M˜na Negra, Lomo Negro, Below Lomo Negro, Cuchillo del Roque, Malpaso Member, and M˜na del Guanche) Holocene subaerial eruptions, distributed along the three rift zones, combining paleomagnetic and 14C methods. We also provide geochemical analyses for nine of them. Results indicate that M˜na Chamuscada and M˜na del Tesoro occurred more recently than previously considered, setting them within the last two thousand years. Conversely, paleomagnetic and 14C ages found for Lomo Negro eruption are consistent with literature data (Villasante- Marcos and Pav´on-Carrasco, 2014) and constrain the occurrence of this event in the XVI century CE. Finally, for Malpaso Member deposits, the two 14C datings obtained by charcoals found below and above the trachytic layer set the eruption during the Holocene epoch, between ~7300 BCE and ~4700 BCE. For the other eruptions, in two cases (Orchilla and Las Calcosas) many possible time windows during the last 14 ka have been found, whereas a few possible ages have been obtained for the others. On the whole, the resulting chronological reconstruction of the recent activity of El Hierro indicates that eruptions occurred unevenly along the three main rifts, with nine eruptions in the WNW rift, six in the NE rift, and four in the SSE rift. We document at least two periods characterized by high eruptive frequency: an old one, between 8000 BCE and 1000 BCE, with eight eruptions, three of which characterized by more evolved compositions (phonotephrite and trachyte), and a recent one, between 1000 BCE and present day, with at least seven eruptions, mainly showing basanite compositions. The new data yield a significant improvement of Holocene eruption chronology, thus are instrumental for a correct evaluation of the volcanic hazard at El Hierro.
    Description: Published
    Description: 107526
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Keywords: Paleomagnetism ; El Hierro ; 04.05. Geomagnetism ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2022-04-01
    Description: The Gutenberg–Richter law and the Omori law are both characterized by a scaling behavior. However, their relation is still an open question. Although several hypotheses have been formulated, a comprehen- sive geophysical mechanism is still missing to explain the observed variability of the scaling exponents b-value and p-value, e.g., correlating the seismic cycle to statistical seismology and tectonic processes. In this work, a model for describing the size-frequency scaling and the temporal evolution of seismicity is proposed starting from simple assumptions. The parameter describing how the number of earthquakes decreases after a major seismic event, p, turns out to be positively correlated to the exponent of the frequency-size distribution of seismicity, b, and related to tectonics. Our findings suggest that p ≈ 23 (b + 1). It implies that a relationship between fracturing regimes, “efficiency” of the seismic process, duration of the seismic sequences and geodynamic setting exists, with outstanding potential impact on seismic hazard. On the other hand, the Gutenberg–Richter law simply reflects the tendency of the segments of the Earth’s crust to reach mechanical stability via constrained energy-budget optimization. Each perturbation has a probability of growing an earthquake or not, depending on disorder within the fault zone and the energy accumulated in the adjoining volume, mainly controlling the evolution of seismic sequences. The results are consistent with the different energy sources related to the tectonic settings, i.e., gravitational in extensional regimes, having higher b and p values, and generating lower maximum magnitude earthquakes with respect to strike-slip and contractional settings, which are rather fueled by elastic energy, showing lower b and p values, and they may generate higher magnitude events.
    Description: Published
    Description: 117511
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: Gutenberg–Richter distribution ; fracturing and fault disorder ; Omori–Utsu law ; earthquake triggering ; tectonic setting ; 04.06. Seismology ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-04-13
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 5
    Publication Date: 2022-03-02
    Description: The continental margin of the Ross Sea has been consistently sensitive to the advance and retreat of the Ross Ice Sheet (RIS) between the interglacial and glacial periods. This study examines changes of the glaciomarine sedimentation on the continental slope and rise to the eastern side of Hillary Canyon in the central Ross Sea, using three gravity cores collected at increasing water depths. Besides older AMS 14C ages of bulk sediments, based on the analytical results, sediment lithology was divided into units A, B1, and B2, representing Holocene, deglacial, and glacial periods, respectively. The sedimentation rate decreased as the water depth increased, with a higher sedimentation rate in the deglacial period (unit B1) than the Holocene (unit A). Biological productivity proxies were significantly higher in glacial unit B2 than in interglacial unit A, with transitional values observed in deglacial unit B1. Biological productivity generally decreased in the Antarctic continental margin during the glacial period because of extensive sea ice coverage. The higher biogenic contents in unit B2 are primarily attributed to the increased transport of eroded and reworked shelf sediments that contained abundant biogenic components to the continental slope and rise beneath the advancing RIS. Thus, glacial sedimentation on the continental slope and rise of the central Ross Sea was generally governed by the activity of the RIS, which generated melt-water plumes and debris flows at the front of the grounding line, although the continental rise might have experienced seasonally open conditions and lateral effects due to the bottom current.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 6
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    Elsevier
    In:  EPIC3Science for the Protection of Indonesian Coastal Ecosystems (SPICE), Science for the Protection of Indonesian Coastal Ecosystems (SPICE), Amsterdam, Netherlands, Elsevier, 457 p., pp. 143-199, ISBN: 978-0-12-815050-4
    Publication Date: 2022-03-04
    Description: Abstract Ecological and social processes of the Spermonde Archipelago, South Sulawesi, Indonesia, have been intensively studied during the Science for the Protection of Indonesian Coastal Ecosystems (SPICE) program. The archipelago is of specific interest to better understand how intensive exploitation of marine resources results in the degradation of reef systems. The projects specifically targeted (1) ecological processes in coral reefs, (2) genetic structure of populations, and (3) social–ecological dynamics relating to resource use, social networks, and governance structures. A modeling component emphasized (4) the integration of different ecological, social, and environmental components. Results indicated that reef resources in the Spermonde Archipelago are intensively exploited and further stressed by pollution effluents from hinterland processes. The lack of alternative livelihoods perpetuates dependencies within the patron–client system of the artisanal fisheries and supports high exploitation and also destructive resource uses. Greater inclusion of local stakeholders in the governance may result in better conservation practices, sustainable resource use, and improved livelihoods for the people. Abstrak Selama proyek SPICE, aspek ekologis dan sosial di perairan Kepulauan Spermonde, Sulawesi Selatan, Indonesia, dipelajari secara intensif. Kepulauan dan perairan ini mengundang banyak perhatian untuk lebih memahami bagaimana tingkat pemanfaatan sumber daya laut yang intensif berakibat pada degradasi sistem terumbu karang. Kerangka kerja proyek penelitian SPICE, secara khusus, menargetkan kajian-kajian mengenai (a) proses ekologis dalam sistem terumbu karang, (b) struktur genetik populasi untuk menentukan konektifitasnya, dan (c) dinamika sosial-ekologi yang berkaitan dengan penggunaan sumber daya, jejaring sosial dan struktur tata kelola. Komponen pemodelan juga dimasukkan kedalam kajian mengenai (d) integrasi berbagai komponen ekologi, sosial dan lingkungan dalam karakterisasi sistem sosial-ekologis. Hasil-hasil penelitian menunjukkan bahwa sumber daya terumbu karang di Kepulauan Spermonde sangat tereksploitasi dan terancam juga oleh limbah polusi dari proses di daratan. Kurangnya mata pencaharian alternatif memperkuat ketergantungan para nelayan tradisional pada sistem patron-klien dan meningkatkan penggunaan sumber daya yang tidak berkelanjutan dan merusak. Keikutsertaan pemangku kepentingan lokal yang lebih erat dalam tata kelola sumber daya alam Kepulauan Spermonde sangat memungkinkan hasil praktik konservasi yang lebih baik, penggunaan sumber daya berkelanjutan, dan peningkatan mata pencaharian bagi masyarakat.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 7
    Publication Date: 2022-03-03
    Description: The Monte San Nicola area (Southern Sicily) offers a spectacular exposure of open-marine sediments that were employed in 1998 for defining the Global Stratotype Section and Point (GSSP) of the Gelasian Stage (Upper Pliocene). After the lowering of the Pliocene/Pleistocene boundary to ca. 2.6 Ma in 2010, the Gelasian GSSP has been redefined as the base of both the Pleistocene Series and the Quaternary Period, which increased its importance and visibility within the scientific community. However, documentation on the Monte San Nicola reference section is still sparse. In the light of its renewed status, we decided to undertake a complete revision of the Gelasian Stage in its type area, in order to evaluate whether the succession of bio- and magnetostratigraphic events that are expected to occur in the interval of relevance are represented adequately in the local record. The results of our investigation demonstrate that the Monte San Nicola succession spans continuously from the upper Piacenzian to the lower Calabrian, and is therefore suitable to host the Unit Stratotype, or even the Astronomical Unit Stratotype, of the Gelasian Stage.
    Description: Published
    Description: 107367
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2022-03-07
    Description: The investigation of the role played by CO2 circulating within the mantle during partial melting and metasomatic/refertilization processes, together with a re-consideration of its storage capability and re-cycling in the lithospheric mantle, is crucial to unravel the Earth's main geodynamic processes. In this study, the combination of petrology, CO2 content trapped in bulk rock- and mineral-hosted fluid inclusions (FI), and 3D textural and volumetric characterization of intra- and inter-granular microstructures was used to investigate the extent and modality of CO2 storage in depleted and fertile (or refertilized) Sub-Continental Lithospheric Mantle (SCLM) beneath northern Victoria Land (NVL, Antarctica). Prior to xenoliths entrainment by the host basalt, the Antarctic SCLM may have stored 0.2 vol% melt and 1.1 vol% fluids, mostly as FI trails inside mineral phases but also as inter-granular fluids. The amount of CO2 stored in FI varies from 0.1 μg(CO2)/g(sample) in olivine from the anhydrous mantle xenoliths at Greene Point and Handler Ridge, up to 187.3 μg/g in orthopyroxene from the highly metasomatized amphibole-bearing lherzolites at Baker Rocks, while the corresponding bulk CO2 contents range from 0.3 to 57.2 μg/g. Irrespective of the lithology, CO2 partitioning is favoured in orthopyroxene and clinopyroxene-hosted FI (olivine: orthopyroxene = 0.10 ± 0.06 to 0.26 ± 0.09; olivine: clinopyroxene = 0.10 ± 0.05 to 0.27 ± 0.14). The H2O/(H2O + CO2) molar ratios obtained by comparing the CO2 contents of FI to the H2O amount retained in pyroxene lattices vary between 0.72 ± 0.17 and 0.97 ± 0.03, which is well comparable with the values measured in olivine-hosted melt inclusions from Antarctic primary lavas and assumed as representative of the partition of volatiles at the local mantle conditions. From the relationships between mineral chemistry, thermo-, oxybarometric results and CO2 contents in mantle xenoliths, we speculate that relicts of CO2-depleted mantle are present at Greene Point, representing memory of a CO2-poor tholeiitic refertilization related to the development of the Jurassic Ferrar large magmatic event. On the other hand, a massive mobilization of CO2 took place before the (melt-related) formation of amphibole veins during the alkaline metasomatic event associated with the Cenozoic rift-related magmatism, in response to the storage and recycling of CO2-bearing materials into the Antarctica mantle likely induced by the prolonged Ross subduction.
    Description: Published
    Description: 106643
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: 4V. Processi pre-eruttivi
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: JCR Journal
    Keywords: CO2 storage ; Sub-Continental Lithospheric Mantle ; Alkaline metasomatism ; Fluid inclusions ; Synchrotron X-ray microtomography ; Inter-granular fluids ; 04.01. Earth Interior ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2022-03-07
    Description: Understanding the sources of potentially toxic elements (PTEs) in soils is a worldwide challenge that requires effective discrimination between geogenic and anthropogenic contributions, particularly in areas with certain geological complexity. This study aims to examine the chemical contents of 23 topsoil samples collected from the surroundings of a fossil fuel power plant in the village of Puerto Libertad (Sonoran Desert, Mexico). The study did not exclusively focus on the source identification of the priority PTEs to evaluate soil pollution. Furthermore, major oxides and immobile trace element (Zr, Hf, and REE: La→Lu) data were provided for a reliable assessment of the provenance of the soils. The relatively high SiO2 contents (65.26–75.42 wt%, anhydrous basis), the Post-Archean Australian Shale (PAAS)-normalized REE patterns, and the uniformity of the values of the Index of Compositional Variability (ICV = 1.11–2.72) and the Chemical Index of Alteration (CIA = 31.65–51.79) suggest that the soils were derived from intermediate to felsic source rocks, controlled by the local weathering of the parent bedrocks, under a low degree of chemical weathering conditions. The PTE data were treated following a robust workflow, which included the use of the enrichment factor (EF), the Spearman rank correlation (ρ), and multivariate statistical analyses allowed the generation of significant elemental associations and the identification of pools related either to the geological background or to anthropogenic activities. The results suggesting that Mo and Zn concentrations present a moderate anthropogenic influence while the concentrations of Pb, Sn, Cu, Cd, As, Cr, and Co are predominantly of geogenic origin. Vanadium (avg. EFV = 3.4) and Ni (avg. EFNi = 4.6) were the most enriched elements in the soils. Moreover, the highest values of the integrated Nemerow Pollution Index (PIN〉3) were recorded at the sampling stations closer to the village, suggesting point-source pollution by the emissions of the power station. Finally, in this paper is traced the extent of the particulate released into the atmosphere, which can be dispersed in a wide area into the Sonoran Desert.
    Description: Published
    Description: 105158
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Environmental geochemistry ; Geogenic sources ; Anthropogenic impact ; Provenance ; Power plant pollution ; Puerto libertad ; PTEs ; Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2022-03-07
    Description: Comprehensive hydrogeochemical studies have been conducted in the Campi Flegrei volcanic aquifer since late 20th century due to the volcanic unrest. In the last decade, groundwater samples were grouped based on the dominant anion species (i.e. bicarbonate, sulfate and chloride) to explain the general hydrogeochemical processes. In this article, 44 groundwater samples are collected from Campi Flegrei aquifer to geochemically and spatially capture the main characteristics of the groundwater body. The hierarchical clustering algorithm is then performed on proportion of bicarbonate, sulfate and chloride, and the optimum number of clusters are determined regarding the results of deep hydrogeochemical investigations published in the past. The collected samples are categorized in the following groups: (1) bicarbonate-rich groundwater; (2) chlorine-rich groundwater; (3) sulfate-rich groundwater; and (4) mixed groundwater. The first group (As = 158.2 ± 169 μg/l, electric conductivity = 1,732.1 ± 1,086 μS/cm and temperature = 25.6 ± 8 ◦C) is mainly derived from poor arsenic meteoric water, but there is significant thermal/seawater contribution in the second one (As = 1,457.8 ± 2,210 μg/l, electric conductivity = 20,118.3 ± 11,139 μS/cm and temperature = 37.1 ± 20 ◦C). Interaction of the bicarbonate-rich groundwater and hydrothermal vapors gives rise to the sulfate-rich groundwater (As = 847.2 ± 679 μg/l, electric conductivity = 3,940.0 ± 540 μS/cm and temperature = 82.8 ± 3 ◦C) around Solfatara volcano. The mixed groundwater (As = 451.4 ± 388 μg/l, electric conductivity = 4,482.9 ± 4,027 μS/cm and temperature = 37.1 ± 16 ◦C) is observed where the three main groundwater groups undergo a mixing process, depending on the hydrogeology of the volcanic aquifer. Contrary to the bicarbonate- and sulfate-rich groundwater, the chlorine-rich and mixed groundwater generally occurs at low piezometric levels (approximately 〈1 m above sea level) near the coastline. The hierarchical cluster analysis provides more information about the volcanic aquifer, particularly when compositional data analysis is applied to study hydrogeochemistry of the homogeneous groundwater groups and to uncover the relationships between variables. Addressing compositional nature of data is recommended in the future studies for developing new tools that help deeper understanding of groundwater evolution in volcanic aquifers and identifying promising precursors of volcanic eruption.
    Description: Published
    Description: 106922
    Description: 4V. Processi pre-eruttivi
    Description: 2IT. Laboratori analitici e sperimentali
    Description: JCR Journal
    Keywords: Hierarchical cluster analysis ; Groundwater evolution ; Hydrothermal system ; Precursors of volcanic eruption ; 03.02. Hydrology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2022-05-02
    Description: We assess about 20 years of onshore and offshore subsidence along a sector of the Upper Adriatic Sea (Italy) coastal areas affected by natural soil compaction and intense anthropogenic activities such as aquifers exploitation and hydrocarbons extraction. Our approach is based on the synergistic use of independent remote sensing and in-situ geodetic data to detect and spatially characterise the deformation pattern by cross-validating the different available measurements. We collect extensive datasets from i) SAR images provided by Envisat, Cosmo- SkyMed and Sentinel-1 missions, ii) GNSS measurements from continuous stations managed by public institutions, local authorities and private companies and iii) Leveling surveys. The cross-validation analysis shows good agreement among all the independent datasets, thus providing a reliable assessment of the ongoing deformation. We detect an onshore and offshore subsidence peak of about 1/-1.5 cm/yr in the proximity of the coastline, close to Lido di Dante and Fiumi Uniti villages, and at the present offshore platform. The outcomes highlight how the integration of different remote sensing and in situ geodetic techniques is successful to retrieve deformation history in time and space in complex areas, where different natural and anthropogenic sources concur to the overall deformation pattern. Moreover, such approach provides a robust support to modelling studies for hazard assessment in both inland and shoreline areas.
    Description: Published
    Description: 102756
    Description: 1TR. Georisorse
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2022-04-29
    Description: We carried out new geological, morphotectonic, geophysical and paleoseismological investigations on the Meduno Thrust that belongs to the Pliocene-Quaternary front of the eastern Southern Alps in Friuli (NE Italy). The study area is located in the Carnic Prealps, where a series of alluvial terraces, linked to both climatic and tectonic pulses characterises the lower reach of the Meduna Valley. In correspondence of the oblique ramp of the Meduno Thrust, the Late Pleistocene Rivalunga terrace shows a set of scarps perpendicular to the Meduno valley, often modified by human activity. In order to reconstruct the tectonic setting of the area and identify the location for digging paleoseismological trenches, integrated geophysical investigations including electrical resistivity tomography, seismic refraction and reflection, ground penetrating radar and surface wave analyses (HVSR, ReMi and MASW), were carried out across the scarps of the Rivalunga terrace. Geophysical surveys pinpointed that in correspondence of the oblique ramp, stress is accommodated by a transpressive thrust system involving all the seismo-stratigraphic horizons apart from the ploughed soil. Trenching illustrated the Meduno Thrust movements during Late Pleistocene-Holocene. Trenches exhibited both shear planes and extrados fracturing, showing deformed alluvial and colluvial units. 14C datings of the colluvial units show that the most recent fault movements occurred after 1360 CE and 1670 CE. The age of the deformed stratigraphic units compared with the earthquakes listed in current catalogues, suggests that the 1776 earthquake (Mw 5.8, Io = 8–9 MCS) could represent the last seismic event linked to the Meduno thrust activity. This study provided new quantitative constraints improving seismic hazard assessment for Carnic prealpine area.
    Description: The research developed in the framework of the agreement between the Regione Autonoma Friuli Venezia Giulia - Direzione Centrale Ambiente ed Energia - Servizio Geologico, the Istituto Superiore per la Protezione e la Ricerca Ambientale (I.S.P.R.A.) and the University of Udine. The project was funded by the Regione Autonoma Friuli Venezia Giulia, Direzione Centrale Ambiente ed Energia, Servizio Geologico (C.I. G.: Z0E0C5EF75, p.i. Maria Eliana Poli).
    Description: Published
    Description: 229071
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Active fault ; Paleoseismology ; Morphogenic earthquake ; Eastern Southern Alps ; Applied geophysics ; NE Italy ; 04.04. Geology ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2022-03-16
    Description: © 〈2021〉. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
    Description: In this paper we explore the efficiency of various machine learning techniques to determine the volcano source,the eruptive formation and the eruption period of volcanic rocks when their chemical contents are known. Withthis aim, we assembled a data set of 9800 volcanic rocks from the open-access literature. The rocks belong toeruptive formations from Somma-Vesuvius, Campi Flegrei, Ischia and Procida volcanoes, in the Neapolitan regionof Italy.The data set includes content of majoroxidesand trace elements,aswell asSrand Nd isotope ratios,erup-tive periods, eruption formations and volcano source. Some discrete numerical variables are missing in certainsamples resulting in data exclusion and measurement inhomogeneity. Our results indicate that, despite such is-sues, some machine learning algorithms have a very high prediction ability, i.e., at 〉70%. The achieved resultsare interesting in order to facilitate the managing of new data for volcanological reconstruction andtephrostratigraphic studies
    Description: Published
    Description: 107254
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
    Publication Date: 2022-03-16
    Description: In this study we present the compositional changes of clinopyroxene (cpx), plagioclase (plg), spinel (sp), and glass experimentally solidified from an Icelandic MORB melt. The starting material was cooled at Patm and fO2 of air, in the thermal range of cooling (ΔTc) between 1300 °C (superliquidus) to 800 °C (solidus) with rates (ΔT/Δt) of 1, 7, 60, 180, 1800, and 9000 °C/h. The run products obtained at 1, 7 and 60 °C/h are holocrystalline, whilst between 60 and 180 °C/h plg disappears, and texture of cpx + sp. shifts from faceted to dendritic. As cooling rate increases, we observe that Fe2O3 decreases and Al2O3 increases in sp. and Al2O3 + Fe2O3 increase and CaO + MgO decrease in cpx. These measured variations mirror changes induced by cooling rate in cation (atoms per formula unit, a.p.f.u.) and molecular abundances of these two crystalline phases. Plg composition shows clear linear trends versus cooling rate. The chemistry of sp., cpx and, to a minor extent, plg solidified from this basaltic liquid is thus strictly related to the cooling rate condition and is similar to those observed in previous investigations on alkaline and evolved basaltic systems. In particular, cpx is the only mineral phase profusely present at all the cooling rates, showing the greatest chemical variations in terms of oxides, cations, and components. The intra-crystalline glass (≤ 50 μm from crystal rims) obtained at 180–1800 °C/h shows compositional variations related to the surrounding crystal growth, evidencing strong supersaturation phenomena (such as dendritic texture) due to the establishment of a diffusion-controlled growth regime. Chemical attributes of mineral phases are also quantitatively related with the maximum (Gmax) and average (GCSD) growth rates of sp., cpx, and plg. When compared with the starting melt composition, the chemistry of cpx suggests the attainment of near-equilibrium crystallization conditions at cooling rate ≤ 60 °C/h, whereas disequilibrium effects are found at cooling rate 〉 60 °C/h. In contrast, plg is in disequilibrium with the initial melt chemistry in all experiments. By using thermometric models, the calculated crystallization of plg takes place at temperatures much lower than those of cpx, when the crystal content is high and the diffusion of cations in the melt is slow due to the higher (residual) melt viscosity. Under such conditions and due to the effect of cooling, the system cannot return to homogeneous concentrations and, consequently, plg more effectively records the disequilibrium partitioning of cations between the growing crystal surface. The data-set reported here captures the entire (superliquidus to solidus) and intrinsic (heterogeneous site-free silicate liquid) solidification behavior from an actual MORB melt from very rapid to extremely sluggish cooling rate. Finally, all analytical relationships found in this work enable careful reconstruction of the solidification conditions of MORB melts, providing novel geo-speedometers for them at high fO2.
    Description: Published
    Description: 120765
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
    Publication Date: 2022-03-16
    Description: Volcano seismology, while its value for surveillance of an active volcano is undebatable, is a very demanding field when it comes to station deployment, maintenance, and finally interpreting the measurements. Most valuable in the past was the deployment of arrays of sensors to evaluate the properties of the entire wavefield in order to classify, locate, and estimate the dominant mechanism of the corresponding sources. While very beneficial, an array of seismographs is very hard to maintain in a permanent installation at an active volcano. With the advent of new instrumentation based on fiber optic technology such as Distributed Acoustic Sensing (DAS) with fiber optic cables as well as Fiber-Optic Gyroscopes (FOG) the measurement of deformation and rotation, i.e., the gradient of the wavefield is feasible. The advantage of the FOG instrumentation with respect to DAS lies in the portability and ease of deployment, which is very similar to standard deployments of traditional seismometers. During a field campaign in summer 2018 we were able to install three FOGs together with classical broadband seismometers in close proximity to the active vents of Stromboli volcano (Italy). We show that with this new six-degrees-of-freedom (6DOF) measurement we are able to analyze the wavefield composition, a property normally reserved for array(s) of seismic sensors. As a first result, we can support earlier array-derived findings that a large portion of the wavefield at Stromboli volcano is formed by SV- and SH- type waves. We also present first locations of these signals facilitating the polarization properties of the combined measurement of gyroscopes and seismometers. They emphasize the benefit of recording wavefield gradients. In addition to these array-like results, the 6DOF recordings show a clear separation of at least three distinct groups of volcanic events of which two are already known and one represents a jetting event that appears nearly invisible for classical seismometers. However, rotational motions - or more general - gradients of the wavefield experience severe distortions by local velocity fluctuations and topography significantly complicating the application of 6DOF techniques at activate volcanoes.
    Description: Published
    Description: 107499
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: 6 DOF ; rotational seismology ; volcanoseismology ; Stromboli ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2022-03-15
    Description: Single rainwater samples were collected in the city of Goma (~1,1 million inhabitants), eastern Democratic Republic of the Congo, from January to June 2013 to draw a baseline for rainwater chemical composition and quality as influenced by the permanent plume of Nyiragongo volcano. This was a better period for a baseline as the neighboring Nyamulagira volcano, only 15 km apart, had no important degassing from its central crater, and hence the recorded volcanic influence on the rainwater chemistry was solely from Nyiragongo's lava lake which has been active since May 2002. The baseline for the rainwater chemistry and quality is important for this highly populated region where rainwater is the unique potable water source for the inhabitants of many villages surrounding the volcanoes, and for some of the inhabitants of the city of Goma. Our results show that samples collected at the crater rim of Nyiragongo were more acidic with pH ranging from 3.70 to 3.82, while the majority of rainwater samples collected in downtown Goma city and to the northeastern zone of the volcano had pH close to 5.7; which represents the value for rainwater from unpolluted continental areas (Berner and Berner, 2012). However, the pH was as low as 3.93 to the west of Nyiragongo volcano because the volcanic plume is directed westward by the dominant local wind direction. The western part of the city of Goma as well as the small town of Sake and many villages (e.g. Rusayo, Mubambiro, Kingi, …) are located in this zone, and experience endemic fluorosis caused by high fluoride in the available water. The mean F- in this zone was 0.38 mg/L, while the southern and northeastern zones had mean F- concentrations on 0.44 and 0.01 mg/L respectively; even though concentrations higher than the WHO guidelines were found in few samples from the western zone (1.69 mg/L) and from the southern zone (3.44 mg/L). Compared to data from Cuoco et al. (2012) obtained during the Nyamulagira 2010 eruption, and from Balagizi et al.2017 and Liotta et al., 2017 obtained during the intense degassing of both Nyiragongo and Nyamulagira lava lakes; we have noted similarity in the spatial variation of the pH, but samples from the present study showed notable lower concentrations of major elements. This is the case for fluoride which is strictly of volcanic origin. For the other major elements, anthropogenic sources, mainly the traffic and wind-blown dust; or other non-volcanic natural sources influenced their concentrations. Thus, the anions (Cl- and SO42-) and cations (Na+, K+, Mg2+, and Ca2+) from the present study are either lower compared to that previously reported in the literature for the Virunga, or are both comparable for the zones impacted by anthropogenic activities.
    Description: Published
    Description: 130859
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Endemic dental fluorosis; Nyamulagira volcano; Nyiragongo volcanic plume; Rainwater chemistry; Rainwater quality baseline
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2022-03-15
    Description: The origin of magmatic fluids along the East African Rift System (EARS) is a long-lived field of debate in the scientific community. Here, we investigate the chemical composition of the volcanic gas plume and fumaroles at Nyiragongo and Nyamulagira (Democratic Republic of Congo), the only two currently erupting volcanoes set on the Western Branch of the rift. Our results are in line with earlier conceptual models proposing that volcanic gas emissions along the EARS mainly reflect variable contributions of either a Sub-Continental Lithospheric Mantle (SCLM) component or a Depleted Morb Mantle (DMM) component, and deeper fluid. At Nyiragongo and Nyamulagira, our study discards a major contribution of a high 3He/4He mantle plume component in the genesis of volcanic fluids beneath the area. High CO2/3He in fumaroles of both volcanoes is thought to reflect carbonate metasomatism in the lithospheric mantle source. As inferred by previous results obtained on the lava chemistry, this carbonate metasomatism would be more pronounced beneath Nyiragongo. This supports the idea of the presence of distinct metasomes within the lithospheric mantle beneath the Western Branch of the rift.
    Description: Published
    Description: 120811
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: East African Rift System ; Volcano ; Gas chemistry ; 04.08. Volcanology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2022-03-17
    Description: Coccolithophores were collected at 21 stations during summer 2016, from coastal and offshore areas of the Central Mediterranean Sea, to describe the ecology of the coccolithophore community integrating information on their abundance, environmental parameters (salinity, temperature, dissolved oxygen, and fluorescence) and oceanographic data. Emiliania huxleyi dominated the assemblage from surface to intermediate layers, while Florisphaera profunda was more abundant in the deep photic zone. Principal Component Analysis revealed that the distribution of coccolithophore taxa was influenced by environmental parameters: K-strategist taxa were related to warm surface waters, whereas lower photic zone taxa were influenced by the development of a Deep Chlorophyll Maximum and high salinity values, well below the thermocline. These results confirmed that a vertical species zonation, as a typical feature of low-middle latitude, characterizes the Central Mediterranean during summer. The distribution of F. profunda once again confirmed its use as a proxy of Deep Chlorophyll Maximum development and paleoproductivity estimates. Gephyrocapsa spp. (=total Gephyrocapsa), and in particular G. oceanica, were more abundant along the Atlantic Water pathway. Finally, the high concentration value of Helicosphaera carteri, recorded in the Ligurian Sea at an offshore station, suggested an expansion of the opportunist nature of this taxon from coastal environments to the offshore areas characterized by high turbidity and high productivity.
    Description: Published
    Description: 101995
    Description: 4A. Oceanografia e clima
    Description: JCR Journal
    Keywords: Living coccolithophores ; Helicosphaera carteri ; Oceanography ; Ecology ; Central Mediterranean Sea ; coccolithophore ecology and oceanography
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2022-03-17
    Description: A high resolution study of calcareous nannofossils has been performed on samples from the Sapropel S1interval deposited in the North Ionian Sea, with the aim to assess the paleoenvironmental changes in the photic zone during this crucial interval in Mediterranean circulation. Calcareous nannofossil data have been integrated with planktonic foraminiferal data recently published from which the paleoclimatic curve has been constructed. Placoliths (namely Emiliania huxleyi) and Florisphaera profunda distributions, along with that of planktonic foraminifer Globigerinoides ruber white, evidence that, after a progressive weakening of surface water mixing, a deep chlorophyll maximum developed just prior to the sapropel deposition. We suggest that these changes took place as a response to enhanced precipitation conditions and riverine discharge as testified by increasing trend of reworked coccoliths and the occurrence of lower salinity taxon Braarudosphaera bigelowii. Calcareous nannofossils also point out that the oceanographic (water column stratification, reduced bottom water ventilation) and biogeochemical (increased primary production) processes that occurred during the S1 formation were particularly dominant during the earliest part of the older S1 warm phase (S1a). Our results support than some reventilation events of the shallow depth of studied site (665 m) occurred to some extent, particularly during the final phases of S1a. The distribution of holococcoliths, more abundant during the cold interruption phase S1i, seems confirm that the preservation of these tiny and delicate coccoliths, highly susceptible to dissolution, is enhanced under seafloor re-ventilation conditions. Finally, we tentatively suggest that preservation also plays a significant role in the distribution of the warm upper photic zone taxa, particularly during the warm S1b interval.
    Description: Published
    Description: 103599
    Description: 4A. Oceanografia e clima
    Description: JCR Journal
    Keywords: Sapropel S1 ; Calcareous nannofossils ; Planktonic foraminifera ; North Ionian Sea ; Mediterranean ; Hydrosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2022-03-17
    Description: The understanding of fault-slip behaviour in carbonates has an important societal impact due to the widespread occurrence and propagation of earthquakes in these rocks. Fault rock variations in carbonates are systematically controlled by the lithology of the faulted protolith: cataclasis and hydraulic fracturing with evidence of past seismic slip commonly affect fault rocks in competent limestone formations whereas widespread pressure-solution and sliding along clay foliation are observed in marly rocks. We performed a series of friction experiments on carbonatic fault rocks sampled from mature thrusts (〉2km displacement) in the Apennines of Italy. We sheared both intact wafers and powdered fault materials at low (10MPa) and in situ(53MPa) normal stress under room-humidity and water-saturated conditions. We used velocity steps (1 to 300μm/s) and slide–hold–slide (3–1000 s holds) to assess the frictional stability and healing behaviour of these rocks. We observe that cataclastic fault rocks derived from competent limestones are characterized by high friction coefficients coupled with significant post-slip restrengthening and velocity-weakening behaviour. Conversely, intact foliated marly tectonites, sheared under the same conditions, show low friction, null post-slip healing and stable velocity-strengthening behaviour suggesting that these rocks deform aseismically. To extrapolate these opposite mechanical behaviours to the entire fault surface we developed a fault model integrating our mechanical data, field observations and balanced geological cross-sections. The mechanical heterogeneities highlighted in the model provide constraints for the distribution of fault patches with higher seismogenic potential.
    Description: Published
    Description: 307–318
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: friction carbonates earthquakes fault
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
    Publication Date: 2022-03-29
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 22
    Publication Date: 2022-03-21
    Description: Changbaishan, an intraplate volcano, is characterized by an approximately 6 km wide summit caldera and last erupted in 1903. Changbaishan experienced a period of unrest between 2002 and 2006. The activity developed in three main stages, including shield volcano (basalts), cone-construction (trachyandesites to trachytes with minor basalts), and caldera-forming stages (trachytes to comendites). This last stage is associated with one of the more energetic eruptions of the last millennium on Earth, the 946 CE, VEI 7 Millennium Eruption (ME), which emitted over 100 km3 of pyroclastics. Compared to other active calderas, the plumbing system of Changbaishan and its evolution mechanisms remain poorly constrained. Here, we merge new whole-rock, glass, mineral, isotopic, and geobarometry data with geophysical data and present a model of the plumbing system. The results show that the volcano is characterized by at least three main magma reservoirs at different depths: a basaltic reservoir at the Moho/lower crust depth, an intermediate reservoir at 10–15 km depth, and a shallower reservoir at 0.5–3 km depth. The shallower reservoir was involved in the ME eruption, which was triggered by a fresh trachytic melt entering a shallower reservoir where a comenditic magma was stored. The trachytes and comendites originate from fractional crystallization processes and minor assimilation of upper crust material, while the less evolved melts assimilate lower crust material. Syn-eruptive magma mingling occurred during the ME eruption phase. The magma reservoirs of the caldera-forming stage partly reactivate those of the cone-construction stage. The depth of the magma storage zones is controlled by the layering of the crust. The plumbing system of Changbaishan is vertically extensive, with crystal mush reservoirs renewed by the replenishment of new trachytic to trachyandesitic magma from depth. Unlike other volcanoes, evidence of a basaltic recharge is lacking. The interpretation of the signals preceding possible future eruptions should consider the multi-level nature of the Changbaishan plumbing system. A new arrival of magma may destabilize a part of or the entire system, thus triggering eruptions of different sizes and styles. The reference model proposed here for Changbaishan represents a prerequisite to properly understand periods of unrest to potentially anticipate future volcanic eruptions and to identify the mechanisms controlling the evolution of the crust below volcanoes.
    Description: National Natural Science Foundation of China (Grant Nos. 41972313 and 41790453), Engineering Research Center of Geothermal Resources Development Technology and Equipment, Ministry of Education, Jilin University, China, INGV Ricerca Libera.
    Description: Published
    Description: 101171
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
    Publication Date: 2022-03-21
    Description: The presence of weak phyllosilicates in mature carbonate fault zones has been invoked to explain weak faults. However, the relation between frictional strength, fault stability, mineralogical composition, and fabric of fault gouge, composed of strong and weak minerals, is poorly constrained. We used a biaxial apparatus to systematically shear different mixtures of shale (68% clay, 23% quartz and 4% plagioclase) and calcite, as powdered gouge, at room temperature, under constant normal stresses of 30, 50, 100 MPa and under room-dry and pore fluid-saturated conditions, i.e. CaCO3-equilibrated water. We performed 30 friction experiments during which velocity-stepping and slide-hold-slide tests were employed to assess frictional stability and to measure frictional healing, respectively. Our frictional data indicate that the mineralogical composition of fault gouges significantly affects frictional strength, stability, and healing as well as the presence of CaCO3-equilibrated water. Under room-dry condition, the increasing shale content determines a reduction in frictional strength, from μ = 0.71 to μ = 0.43, a lowering of the healing rates and a transition from velocity-weakening to velocity-strengthening behavior. Under wet condition, with increasing shale content we observe a more significant reduction in frictional strength (μ = 0.65–0.37), a near-zero healing and a velocity strengthening behavior. Microstructural investigations evidence a transition from localized deformation promoted by grain size reduction, in calcite-rich samples, to a more distributed deformation with frictional sliding along clay-enriched shear planes in samples with shale content greater than 50%. For faults cutting across sedimentary sequences composed of carbonates and clay-rich sediments, our results suggest that clay concentration and its ability to form foliated and interconnected networks promotes important heterogeneities in fault strength and slip behavior.
    Description: Published
    Description: 228811
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Carbonate faults ; Fault slip behavior ; 04.02. Exploration geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
    Publication Date: 2022-03-21
    Description: The 2016 Central Italy earthquake sequence is characterized by remarkable rupture complexity, including highly heterogeneous slip across multiple faults in an extensional tectonic regime. The dense coverage and high quality of geodetic and seismic data allow us to image intriguing details of the rupture kinematics of the largest earthquake of the sequence, the Mw 6.5 October 30th, 2016 Norcia earthquake, such as an energetically weak nucleation phase. Several kinematic models suggest multiple fault planes rupturing simultaneously, however, the mechanical viability of such models is not guaranteed. Using 3D dynamic rupture and seismic wave propagation simulations accounting for two fault planes, we constrain “families” of spontaneous dynamic models informed by a high-resolution kinematic rupture model of the earthquake. These families differ in their parameterization of initial heterogeneous shear stress and strength in the framework of linear slip weakening friction. First, we dynamically validate the kinematically inferred two-fault geometry and rake inferences with models based on only depth-dependent stress and constant friction coefficients. Then, more complex models with spatially heterogeneous dynamic parameters allow us to retrieve slip distributions similar to the target kinematic model and yield good agreement with seismic and geodetic observations. We discuss the consistency of the assumed constant or heterogeneous static and dynamic friction coefficients with mechanical properties of rocks at 3-10 km depth characterizing the Italian Central Apennines and their local geological and lithological implications. We suggest that suites of well-fitting dynamic rupture models belonging to the same family generally exist and can be derived by exploiting the trade-offs between dynamic parameters. Our approach will be applicable to validate the viability of kinematic models and classify spontaneous dynamic rupture scenarios that match seismic and geodetic observations as well as geological constraints.
    Description: T.U., T., D.L., and A.-A. Gabriel are supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (TEAR, agreement No. 852992 and ChEESE, grant no. 823844), the German Research Foundation (DFG project grants no. GA 2465/2-1 and GA 2465/3-1) and by KAUST-CRG (grant no. ORS-2017-CRG6 3389.02). E.T. was supported by Progetti di Ricerca Sapienza (RM120172A2EAC019). Computing resources were provided by the Leibniz Supercomputing Centre (LRZ, project no. pr63qo on SuperMUC-NG).
    Description: Published
    Description: 117237
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: earthquake source ; dynamic rupture ; high-performance computing ; frictional heterogeneity ; 04.06. Seismology ; 05.05. Mathematical geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
    Publication Date: 2022-03-22
    Description: Crustal seismicity is in general confined within the seismogenic layer, which is bounded at depth by processes related to the brittle-ductile transition (BDT) and in the shallow region by fault zone consolidation state and mineralogy. In the past 10-15 years, high resolution seismological and geodetic data have shown that faulting within and around the traditional seismogenic zone occurs in a large variety of slip modes. Frictional and structural heterogeneities have been invoked to explain such differences in fault slip mode and behaviour. However, an integrated and comprehensive picture remains extremely challenging because of difficulties to properly characterize fault rocks at seismogenic depths. Thus, the central-northern Apennines provide a unique opportunity because of the integration of deep-borehole stratigraphy and seismic reflection profiles with high resolution seismological data and outcrop studies. These works show that seismic sequences are limited within the sedimentary cover (depth 〈 9-10 km), suggesting that the underlaying basement plays a key-role in dictating the lower boundary of the seismogenic zone. Here we integrate structural data on exhumed outcrops of basement rocks with laboratory friction data to shed light on the mechanics of the Apenninic basement. Structural data highlight heterogeneous and pervasive deformation where foliated and phyllosilicate-rich rocks surround more competent quartz-rich lenses up to hundreds of meters in thickness. Phyllosilicate horizons deform predominantly by folding and foliation-parallel frictional sliding whereas quartz-rich lenses are characterized by brittle signatures represented by extensive fracturing and minor faulting. Laboratory experiments revealed that quartz-rich lithologies have relatively high friction, μ ≈ 0.51, velocity-strengthening to neutral behaviour, and elevated healing rates. On the contrary, phyllosilicate-rich (muscovite and chlorite) lithologies show low friction, 0.23 〈 μ 〈 0.31, a marked velocity strengthening behaviour that increases with increasing sliding velocity and negligible rates of frictional healing. Our integrated approach suggests that in the Apenninic basement deformation occurs along shear zones distributed on thickness up-to several kilometres, where the frictionally stable, foliated, and phyllosilicate-rich horizons favour aseismic deformation and therefore confine the depth of major earthquake ruptures and the seismogenic zone.
    Description: Published
    Description: 117444
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
    Publication Date: 2022-02-28
    Description: Leucititic rocks, K-foiditic in composition are volumetrically important in the Colli Albani (also known as Alban Hills) volcanic district (Central Italy) especially during the most explosive phases of activity (〉200 km3). The Colli Albani tephra in distal (〉500 km) deposits indicates that K-foiditic magma chambers fed large explosive eruptions (i.e., tens of km3 of pyroclastic rocks). Major oxides, trace elements and Raman spectra were measured on the glasses and minerals occurring in the K-foiditic scoria clasts of the ~530 kyr-old Tufo del Palatino, erupted in the Colli Albani volcanic district. The Colli Albani pre-eruptive magmatic system is characterized by the aH2O 〈 1 and high CO2 activ- ity in the melt, as testified by the CO3 in the clinopyroxene melt inclusions, by the early crystallization of CO3-bearing apatite and by the high CO2 activity in the free volatile phase that led to crystallization of calcium carbonate in the scoria clast vesicles. The K-foiditic magmas plot on the Cpx + Lc + melt divariant surface of the Ol-Cpx-Lc-Mel- H2O-CO2, P ≥ 0.2 GPa and T ≤ 1100 °C. The assimilation of cold carbonate by hot magmas is an important open- system process allowing the establishment of aH20 〈 1 condition in the volatile-rich, Colli Albani magma chambers where the stability fields of the olivine and phlogopite are reduced in favor of clinopyroxene and leucite. Trace ele- ment modelling indicates large amount of carbonate assimilation (~12.4 wt%) involved in the differentiation process that origins the K-foiditic magmas starting from a K-rich, phonotephritic parental magma. The large amount of as- similate carbonate is consistent with the peculiar distribution of the latent heat across the crystallization interval of the phonotephritic parental magma. The isenthalpic assimilation process is very efficient in the phonotephritic magma because the crystallization of clinopyroxene and leucite in equilibrium with a K-foiditic melt proceeds over a relatively large temperature interval (〉200 °C) and the K-foiditic melt shows low viscosity (104Pa·s at 1000 °C). Actually, the low melt viscosity, that increases the growth rate, and the large temperature interval of crys- tallization are intrinsic factors that increase the release of the latent heat of crystallization from the phonotephritic parental magma. Extrinsic factors enhancing the assimilation process efficiency are the thickness (〉4 km) and the depth (down to 5–7 km) of the carbonate substrate in the Colli Albani volcanic district.
    Description: Published
    Description: 106239
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
    Publication Date: 2022-02-28
    Description: New analyses of marine terraces in the Tyrrhenian Sea margin of Basilicata - northern Calabria (southern Italy) have been carried out. In the study area, c. 25 km in length, an impressive flight of marine terraces occurs, with the highest terraces reaching ~160 m a.s.l. Detailed geomorphological-stratigraphical analyses on remnants of paleoshorelines located within 60 m a.s.l. have shown that the rocky coast of the investigated coastal stretch has been affected by multiple relative sea-level fluctuations, during which reworking of older shorelines has occurred. Dating of the coral Cladocora caespitosa and speleothems, either predating or postdating single paleoshorelines, has allowed the construction of a chronological framework for the identified relative sea-level markers, and their correlation with MIS 7, MIS 6e and distinct peaks of MIS 5. A mean uplift rate of c. 0.25 mm/y since the Last Interglacial has been quantified, one order of magnitude larger than previous estimates. The uplift rate value has been used to infer the elevations of MIS 5a, 5c and 6e sea level peaks, which are higher than those reported in most sea level curves worldwide, although consistent with several findings from the western Mediterranean. Our results demonstrate that a mere sequential correlation may be misleading in the interpretation of flights of marine terraces and indicates that multiple age controls are crucial to unravelling the complex interaction between uplift and sea-level fluctuations in uplifted coastal areas. The reconstructed MIS 5a, 5c and 6e sea level paleo-elevations, besides contributing to the assessment of late Quaternary sea-level fluctuations in the Mediterranean Sea, may contribute to constrain coeval ice sheets volume variations.
    Description: Published
    Description: 107978
    Description: 7SR AMBIENTE – Servizi e ricerca per la società
    Description: JCR Journal
    Keywords: Marine terraces ; morpho-stratigraphy ; Geochronological dating ; MIS 5 ; MIS 6e ; Tyrrhenian margin
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
    Publication Date: 2022-02-28
    Description: The behaviour of dry and wet volcanic granular flows is one of the main research topics in present day geophysics and volcanology. It involves various disciplines (e.g. sedimentology, geophysics, fluid dynamics) and investigation techniques (e.g. field studies, laboratory experiments, computational fluid dynamics). The vast interest is justified by the complex nature of these flows and their very dangerous nature that threaten millions of people around the world. In the last decade, computational fluid dynamics has become one of the main instruments used to reproduce past events of volcanic granular flows or to predict their behaviour and potential hazard. In this study, we tested two of the most used codes for simulating volcanic granular flows, TITAN2D and FLO2D, against well studied natural cases (the 1998 wet granular flows in the Sarno area and the 2005 block and ash flows at Colima volcano) and large-scale experiments on granular flows. Comparison between simulated parameters and real ones were carried out in order to evaluate strengths and weaknesses of the two numerical codes. TITAN2D results showed how the basal friction angle is fundamental to control numerical simulations and its dependence on the topographic complexities, DEM resolution and slope-angle ratio. Simulation of large scale experiments offered a good relationship between slope angle ratio at break in slope and basal friction angle, which is useful for application to small drainage basins with not complex channel morphology. FLO2D suffers the lack of rheometric parameters for volcaniclastic material, but is less sensitive of DEM resolution with respect to TITAN2D.
    Description: Published
    Description: 107146
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2022-02-28
    Description: Glacial-interglacial variations in ice volume and sea level are essential components of the Pleistocene global climate evolution. Deciphering the timing of change of these key climate parameters with respect to the insolation forcing is central to understanding the processes controlling glacial terminations. Here we exploit the sensitivity of the Paleo Tiber River (central Italy) to sea-level forced changes in the base level and the frequent occurrence of datable tephra layers in its sedimentary successions to reconstruct the timing of the relative sea-level (RSL) change between 450 and 403 ka, i.e., across the glacial termination (T-V) that marks the transition between Marine Isotope Stage (MIS) 12 and MIS 11. The analysis hinges on new stratigraphic data, tephra geochemical fingerprinting, and 40Ar/39Ar dating from a fluvial section that represents the inland counterpart of the near mouth, coastal aggradational succes- sions of the San Paolo Formation (SPF). Tephra correlation indicates that the morpho-stratigraphic record of the inland section is as sensitive to the sea-level change as its coastal counterparts, which makes it ideal to complement previous RSL reconstructions from the Tiber River catchment basin, thereby providing a more detailed picture of the sea-level history across T-V. Combined sedimentological and morphological proxies of the composed inland-coastal SPF record document the occurrence of two phases of relatively rapid sea-level rise, here interpreted as meltwater pulse (MWP) events. The earlier MWP occurred between ~450 and ~445 ka and matches a relatively minor episode of the sea-level rise documented in an existing RSL record, while the younger MWP at ~430 ka corresponds to the high amplitude sea-level rise that marks T-V. We find that both MWPs coincide with episodes of ice-rafted debris deposition in the North Atlantic (Heinrich-like events) and with attendant Southern Hemi- sphere warming, plausibly associated with the bipolar seesaw.
    Description: Published
    Description: 106976
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
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    Elsevier
    Publication Date: 2022-02-10
    Description: The airborne magnetic method was established a few decades ago, as a strong tool in mining and petroleum exploration. Several economically relevant discoveries are often credited to aeromagnetism. Geological reconnaissance and mapping, deep crustal and upper mantle studies, environmental characterization, and national and international security issues can greatly benefit from the aeromagnetic method, as compared with other geophysical prospecting schemes. The rapid rate of coverage and the low cost per unit area explored represent just a few among the many advantages of the technique. Consequently, large-scale airborne magnetic surveys have been carried out in various parts of the globe. The amount of direct discoveries of ore bodies by means of aeromagnetism is impressive. Large magnetic iron deposits found in the early 1960s are in Southern California, Missouri, Nevada, Pennsylvania, Quebec, Ontario, and elsewhere. In the field of petroleum exploration, the method has also been used, although with less direct application. Depth to magnetic basement estimation in sedimentary basins narrows down areas of interest where to conduct exploration surveys in detail by means of more costly methods. The most relevant use of airborne magnetic results is crustal imaging and characterization. Nowadays, geology is interpreted in three dimensions using a digital aeromagnetic map.
    Description: Published
    Description: 675-688
    Description: 1T. Struttura della Terra
    Description: 4T. Sismicità dell'Italia
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare
    Description: 5A. Ricerche polari e paleoclima
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: 1TR. Georisorse
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: 6SR VULCANI – Servizi e ricerca per la società
    Description: 7SR AMBIENTE – Servizi e ricerca per la società
    Keywords: aeromagnetism ; potential fields ; magnetic anomaly ; 04.02. Exploration geophysics ; 04.05. Geomagnetism ; 04.07. Tectonophysics ; 04.08. Volcanology ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 31
    Publication Date: 2022-02-18
    Description: Unravelling the physical state and properties of mantle rocks is crucial for understanding both plate tectonics, seismic activity, and volcanism. In this context, the knowledge of accurate elastic parameters of constituent mineral phases, and their variations with pressure (P) and temperature (T), is an essential requirement, that coupled with the thermal state of the lithosphere can provide a better understanding of its petrophysics and thermochemical structure. In this paper, we present an assessment of the thermoelastic parameters [in the form of P–V–T–K Equations of State (EoS)] of orthopyroxene, clinopyroxene, spinel and garnet based on X-Ray diffraction data and direct elastic measurements available in literature. The newly developed EoS are appropriate to describe the elastic behaviour of these phases under the most relevant P–T conditions and bulk compositions of the Earth’s mantle. In combination with the published EoS for mantle olivine and magnesiochromite, these EoS are suitable to calculate the physical properties of mantle peridotites and their variation with P and T. Thanks to these EoS, we can evaluate how the variations in bulk composition and thermal regimes affect the density structure of the lithospheric mantle. Accordingly, the density structure of fertile and depleted peridotitic systems was calculated along the 35, 45 and 60 mWm􀀀 2 geothermal gradients at P comprised between 1 and 8 GPa. Under very cold geothermal gradients, the density of both fertile and depleted peridotitic systems progressively increases with depth, whereas under relatively hot conditions a first downwards decrease from 1 to ca 3 GPa is observed, followed by an increase downward. In mantle sections characterized by intermediate geotherms (45 mWm􀀀 2), the behaviour of the two systems differs up to ca 4 GPa, as the density of the depleted system remains nearly constant down to this depth whereas it moderately increases in the fertile system. The results of our simplified parameterisation, in agreement with classical thermodynamic modelling, indicate that the density structure of the lithospheric mantle is predominantly controlled by the P – T gradient variations, with some compositional control mostly arising at cold-intermediate thermal conditions. Integrated by geophysical and thermodynamic modelling, the newly developed and selected EoS could provide an alternative strategy to infer the elastic properties of mineral phases and peridotite rocks, under the most relevant P–T conditions and compositions of the Earth’s mantle, without requiring sets of end-member properties and solution models.
    Description: Published
    Description: 106483
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2022-02-18
    Description: Plutons in crustal shear zones may exploit inherited structures, interfere with strain localizing or be deformed passively. To constrain the relative timing of such tectono-magmatic relationships in natural settings is not always straight-forward. We here present sandbox-type analogue model experiments simulating magma emplacement into simple and transtensional crustal shear zones to test the diagnostic potential of pluton shape with respect to timing and setting. Observations based on surface deformation and intrusion shape exemplify the interplay between evolving and inherited tectonic structures and magma uprising. We observe markedly asymmetric intrusions in association with dikes reflecting the regional stresses, fault pattern and finite strain field. At the same time, the presence of an intrusion modifies the tectonic evolution, but only transiently, resulting in short-lived faults, reactivation and inversion. Diagnostic attributes include the pluton’s aspect ratio, its orientation and amplitude as well as dike association. Accordingly, syn-tectonic intrusions show the highest pluton amplitudes, but only intermediate elongation compared to other scenarios. They are oriented parallel to Riedel shears in simple shear, respectively to the compression direction in transtension. Post-tectonic intrusions are least elongated, have medium amplitudes and exploit Riedel shears. Pre-tectonic intrusions are characterized by lowest amplitudes but the highest aspect ratios and are parallel to the finite elongation direction. Intrusions in transtensional shear zones are generally of less elongate than those in simple shear zones. Experimental results are tested against observations from natural examples validating the diagnostic potential of pluton shape for the timing and the tectonic setting of the emplacement.
    Description: Published
    Description: 104417
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2022-02-16
    Description: In seismic modelling, fault planes are normally assumed to be flat due to the lack of data which can constrain fault morphology. However, incorporating 3D fault morphology is important for modelling several phenomena, for example calculating mainshock induced stress changes. We utilize a data-analytical method to unveil the 3D rupture morphology of faults using unsupervised clustering techniques applied to earthquake hypocenters in seismic sequences. We apply this method to the 2009 L’Aquila seismic sequence which involved a MW 6.1 mainshock on April 6th. We use a dataset of about 50,000 relocated events, mostly microearthquakes, reaching magnitude of completeness equal to 0.7. Clustering distinguishes the earthquakes as occurring in three main clusters along with other minor fault segments. We then represent the morphology of the main Paganica fault system (responsible for the largest mainshock) using splines. This method shows promise as a step toward robustly and quickly obtaining 3D rupture morphologies where earthquake sequences have been monitored. The 3D model is presented interactively online, and the processing is presented in an interactive Jupyter Notebook (https://bit.ly/2MnCFdj).
    Description: Published
    Description: 228756
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: Fault morphology Clustering L’Aquila earthquake sequence ; Clustering ; L’Aquila earthquake sequence
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
    Publication Date: 2022-02-22
    Description: The westernmost Mediterranean hosts part of the plate boundary between the European and African tectonic plates. Based on the scattered instrumental seismicity, this boundary has been traditionally interpreted as a wide zone of diffuse deformation. However, recent seismic images and seafloor mapping studies support that most of the plate convergence may be accommodated in a few tectonic structures, rather than in a broad region. Historical earthquakes with magnitudes Mw 〉 6 and historical tsunamis support that the low-to-moderate instrumental seismicity might also have led to underestimation of the seismogenic and tsunamigenic potential of the area. We evaluate the largest active faults of the westernmost Mediterranean: the reverse Alboran Ridge, and the strike-slip Carboneras, Yusuf and Al-Idrissi fault systems. For the first time, we use a dense grid of modern seismic data to characterize the entire dimensions of the main fault systems, accurately describe the geometry of these structures and estimate their seismic source parameters. Tsunami scenarios have been tested based on 3D-surfaces and seismic source parameters, using both uniform and heterogeneous slip distributions. The comparison of our results with previous studies, based on limited information on the fault geometry and kinematics, indicates that accurate fault geometries and heterogeneous slip distributions are needed to properly assess the seismic and tsunamigenic potential in this area. Based on fault scaling relations, the four fault systems have a large seismogenic potential, being able to generate earthquakes with Mw 〉 7. The reverse Alboran Ridge Fault System has the largest tsunamigenic potential, being able to generate a tsunami wave amplitude greater than 3 m in front of the coasts of Southern Spain and Northern Africa.
    Description: Published
    Description: 106749
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Western Mediterranean ; Seismogenic potential ; Tsunamigenic potential ; Numerical modelling ; Active faults ; Active seismic data ; 04.04. Geology ; 04.07. Tectonophysics ; 04.06. Seismology ; 05.08. Risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2022-02-21
    Description: This work presents hydrochemical results for groundwater and dissolved gas samples collected from a thermal and cold aquifer in the Juchipila Basin, in southern Sierra Madre Occidental, central Mexico. Thermal springs in the Juchipila Basin reach temperatures of 60 ◦C, these manifestations are not related to recent or active volcanism as are all the known geothermal fields in Mexico. The thermal waters (〉32 ◦C) are Na-HCO3 and Na-SO4 type, with an anomalous concentration of F, B, Li, and As. Their chemistry likely results from water-rock interaction processes. The cold waters (〈32 ◦C) have a Ca-HCO3 composition typical of recent infiltration and shallow flow, but they have an anomalous concentration of NO3. The δ2H and δ18O indicate a common meteoric source for the warm and cold water plotting along an evaporation line. The waters have higher CO2 and He concentrations than the air-saturated water. The helium composition is mainly atmospheric and terrigenous with a mantle helium contribution of up to 14%. This suggests that faults affecting the region are deeply rooted, permitting mantle helium uprise. Geothermometry gives mean reservoir temperatures of 58–102 ◦C. Based on these results, we propose a model of hydrothermal circulation in the Juchipila Basin, in which rainwater infiltrates deeply through the graben edges fault system, dissolves ions and crustal helium, incorporates mantle helium, while heated by the geothermal gradient, and eventually surges and mixes with the cold, shallow aquifer along faults cutting the whole succession within the graben.
    Description: Published
    Description: 102076
    Description: 1TR. Georisorse
    Description: JCR Journal
    Keywords: Hydrogeochemical processes ; Helium isotopes ; Water stable isotopes ; Unconventional geothermal system ; Mexico
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2022-02-21
    Description: Unmanned aerial systems (UAS, aka drones) are being used to map macro-litter on the environment. Sixteen qualified researchers (operators), with different expertise and nationalities, were invited to identify, mark and categorize the litter items (manual image screening, MS) on three UAS images collected at two beaches. The coefficient of concordance (W) among operators varied between 0.5 and 0.7, depending on the litter parameter (type, material and colour) considered. Highest agreement was obtained for the type of items marked on the highest resolution image, among experts in litter surveys (W = 0.86), and within territorial subgroups (W = 0.85). Therefore, for a detailed categorization of litter on the environment, the MS should be performed by experienced and local operators, familiar with the most common type of litter present in the target area. This work provides insights for future operational improvements and optimizations of UAS-based images analysis to survey environmental pollution.
    Description: Published
    Description: 112542
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
    Keywords: Coastal pollution; Plastics; Remote sensing; Unmanned aerial vehicle (UAV); Waste management
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publication Date: 2022-02-24
    Description: We investigated the late Quaternary throw distribution of the main normal fault that ruptured during the Mw 6.5 2016 earthquake in central Italy by means of a high-resolution structure-from-motion (SfM)-derived Digital Surface Model (DSM). We focused on a key area along the Cordone del Vettore fault (CDV), which is part of the Vettore-Bove fault system (VBFS). The CDV displays a prominent compound post-glacial scarp that allowed the reconstruction of the along-strike cumulative throw distribution. We propose a geometric approach to calculate the CDV fault throw distribution from the reconstruction of a displaced glaciation-related erosional surface, used as a geomorphic marker, and a series of closely spaced cross profiles. The proposed calculation accounts for both the slip vector direction and the degraded scarp top, including field data on fault dip angles. Following this approach, we recognized two scarps with a minimum average fault throw of ~21 m and ~35 m for this section of the investigated fault strand. The correlation with the possible post-LGM (Last Glacial Maximum) deglaciation phases of the erosional surface suggests a minimum scarp age of 25–27 ka cal BP. Such an age provides a reasonable CDV fault throw rate of ~0.8 mm/a, comparable with known long-term throw rates of the VBFS and active Apennines normal faults. By comparing the reconstructed long-term Cordone del Vettore throw distribution with the 2016 coseismic one, ~24 2016-like surface faulting events are required to generate the main cumulative scarp, under the assumption of constant slip per event. This, along with the age of the scarp, yields an average earthquake recurrence time interval of ~1100 a. These results suggest the presence of multiple regional markers that correlates with different LGM (if not pre-LGM) major glacial phases, whose erosional processes allow the preservation of pre-existing bedrock fault scarp remnants.
    Description: Published
    Description: 107784
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: earthquake ; surface rupture ; active tectonics ; geomorphology ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publication Date: 2022-02-24
    Description: Dissolution of clinopyroxene (cpx) in a K-basaltic melt from the Campi Flegrei Volcanic District (Italy) has been investigated through dissolution and dissolution-crystallization experiments at pressure of 0.8 GPa, superliquidus temperature of 1350 ◦C, and dwell times between 0.5 and 1 h. The obtained dissolution rates range from 7.9⋅10− 6 cm s− 1 to 6.1⋅10− 6 cm s− 1 as a function of dwell time. In the dissolution-crystallization experiment (1300 ◦C; 0.8 GPa; 2 h), the formation of overgrowth rims accompanied by new cpx crystals suggests that the injection of recharge magmas in basaltic reservoir may lead to inverse or oscillatory zonation. The interaction between cpx and K-basaltic melt at ~1570 ◦C was studied by in situ radiography using synchrotron radiation combined with the Paris-Edinburgh press. This resulted in cpx resorption to occur depending on the temperature conditions with respect to the liquidus temperature of the cpx (TcpxL). The calculated cpx dissolution rates are ~5⋅10− 3 cm s− 1 at T ≤ TcpxL and ~ 3⋅10− 2 cm s− 1 at T ≥ TcpxL. The role of crystal dissolution in the estimation of magma residence times has been also tested for a natural magmatic system by interpolating the dissolution rates (~10− 5–10− 6 cm s− 1) with the textural data of cpx phenocrysts from the Agnano-Monte Spina pyroclastic deposit at Campi Flegrei caldera (Campanian region, Italy). Results from calculations indicate that the time required for partial or complete resorption of phenocrysts varies from ~0.5 to ~40 h, and that the effect of crystal dissolution may be relevant to estimate magma residence times whether signifcant dissolution occurs during magma mixing processes.
    Description: Published
    Description: 120533
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    Publication Date: 2022-02-25
    Description: During the 2016–2017 Central Italy earthquake sequence, a series of moderate to large earthquakes M 〉 5 occurred near the Amatrice and Norcia towns. These events are recorded on a dense seismic network, providing relevant observational evidence of complex earthquakes in time and space. In this work, we used this substantial data set to study the ground-motion characteristics of the Norcia earthquake M6.5 on October 30, 2016, through a broadband ground-motion simulation. Three-component broadband seismograms are generated to cover the entire frequency band of engineering interest. Low and high frequencies are computed considering the heterogeneous slip rupture model of Scognamiglio et al. (2018) [1]. High frequencies are calculated using a stochastic approach including P, SV, and SH waves, while low frequencies are obtained through a forward simulation of the kinematic model at the various stations. To predict earthquake-induced ground motions in the area, we adopted region-specific attenuation and source scaling parameters derived by Malagnini et al. (2011) [2]. Ground-motion parameters, including peak ground acceleration (PGA), peak ground velocity (PGV) and spectral amplitudes, are calculated at the selected sites adopting physics-based parameters to understand better the earthquake fault rupture, the wave propagation, and their impacts on the seismic hazard assessment in the region. We showed that combining the fault rupture history over the entire frequency spectrum of engineering interest, the attenuation characteristics of the seismic wave propagation, and the properly defined site responses can improve the prediction of ground motions and time histories, especially in near seismic sources.
    Description: Published
    Description: 106866
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: Ground-motion simulation ; Hybrid Method ; 30 October 2016 Norcia earthquake ; Site effects ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
    Publication Date: 2022-02-25
    Description: Gypsum plasterboards are nowadays very appreciated in buildings, mainly due to their lightness, thermal insulation and suitable sound transmission loss when used in double walls. However thermal and acoustic features of gypsum plasterboard can be enhanced. In the present study an innovative method, consisting in the direct addition of a pre-manufactured foam to gypsum pastes is used to increase the gypsum porosity improving sound absorption, lightness and thermal insulation features. In this aim, the role of both different amounts and dilutions of a vegetal foaming agent on the main physical, mechanical and microstructural characteristics of the gypsum was experimentally investigated. Moreover, also X-ray computed micro tomography technique (Micro- CT) was carried out in order to investigate the 3D internal microstructure of the materials. The results confirmed the effectiveness of the foaming agent in increasing the gypsum porosity, with a linear correlation between densities and mechanical strengths. Moreover, the presence of large bubbles, mainly connected each other, involved in a strong reduction of the thermal coefficient (λ), from 0.57 W/m∙K of REF sample to 0.25 W/m∙K of LG10_5% sample, and in a strong increase of the normal sound absorption coefficient (α0), from 0.06 of REF sample to 0.20 of LG10_5% sample. Finally, in the light of the results obtained by the present research, the use of a pre-whipped vegetal foaming agent represents a suitable way to obtain lightweight gypsum-based materials with enhanced thermal and acoustic properties.
    Description: Published
    Description: 124948
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2022-02-25
    Description: The coastal vulnerability along the Mediterranean coasts is increasing, especially in response to the occurrence of tropical-like cyclones, known as Medicanes, which have become more intense than in the past. A peculiar case was the impact of Medicane Zorbas in September 2018 along the coasts of south-eastern Sicily, where it caused inland flooding and damages to the socio-economic activities. Here, Zorbas effects are reconstructed through post-event geomorphological surveys, interviews with direct witness and analyses of video recorded by surveillance systems or found in social media. These data allowed us to assess the flooding extent on seven coastal sectors located between Thapsos Peninsula and Marzamemi. Flooding caused by Zorbas appears to be greater than those produced by the main seasonal storms affecting the areas from 2015 to 2019; nevertheless, it is comparable with the flooding generated by Medicane Qendresa that impacted south-eastern Sicily in 2014. Wave propagation and extreme water level modelling, performed for the main storm events that occurred in the area since 2005, and analyses of data recorded by tide gauges of Catania, Porto Palo di Capo Passero and Malta since 2008, showed that Medicanes generate greater flooding than seasonal storms because they can induce higher and longer surge along the coastline. Collected data indicated that the surge generated by Zorbas reached a maximum value between about 0.8 m and 1.2 m above mean sea level (msl) along the coast of south-eastern Sicily. Results highlighted the need to better evaluate the coastal hazard related to the propagation of Medicanes, especially in the context of future climate change when these events will probably be characterized by longer duration and greater intensity than at the present.
    Description: Published
    Description: 106556
    Description: 4A. Oceanografia e clima
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
    Publication Date: 2022-02-25
    Description: In the last decades, investigating geochemistry of sea sediments has been challenging in the eastern sector of Pozzuoli Bay, source of the metal(loid)s has been a matter of debate and the proposed origin of potentially toxic elements (PTEs) has been occasionally inconsistent. In this study, compositional data analysis (CoDA) was used because the results are independent of the measurement unit, the selected subgroup of elements and the order of chemicals in the dataset. The robust variant of principal component analysis (PCA) indicated that Hg, Cd, Cu, Pb and Zn were positively correlated with mud and organic matter in the sediments deposited in front of the former industrial site. Concentrations of these metals decrease along the cores and in the distal zone. Nevertheless, Al, As, V, Fe, Cr, Ni and sand form an association along the coast which strengthens with increasing distance from fumaroles in the proximal zone. It suggests that arsenic was mainly originated from the pyroclastic deposits of Campi Flegrei and some of the seepages with hydrothermal component, supported by low contribution of the variables in robust PCA of the sediments from distal zone. Therefore, this pioneering article suggests CoDA as a powerful tool for answering the long-lasting questions over sediment geochemistry in polluted areas.
    Description: Published
    Description: 129955
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Bagnoli industrial site; Campi Flegrei; Fractal analysis; Isometric log-ratio; Robust principal component analysis; Symmetric coordinate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
    Publication Date: 2022-02-25
    Description: In our original paper (Buono et al., 2020), we investigated the dynamics of degassing (e.g., bubble nucleation and growth, degassing styles and regimes) of H2O-, CO2- and H2O-CO2-rich evolved alkaline melts over a wide range of variables (final pressures, decompression rates, volatile compositions and contents, temperatures) through a comprehensive review of previous and new HP (high pressure)-HT (high temperature) decompression experiments. The criticism of Allabar and Nowak regards a restricted part of our results, i.e., those concerning homogeneous bubble nucleation from our new experiments on H2O-rich melts. Their aim is refusing the classical nucleation theory (CNT), widely accepted in literature to explain homogeneous bubble nucleation in magmas, for evolved alkaline melts in favour of the spinodal decomposition. We found that the Authors of the Comment do not provide any new evidence in support of their thesis, but they keep only arbitrary and erroneous conjectures of our new experimental data. As we stated in our original paper, the evaluation of the specific bubble nucleation mechanism (CNT vs. spinodal decomposition) is beyond the scope of our research, as appropriate studies on both experimental and natural products would be necessary to shed light on this complex issue.
    Description: Published
    Description: 103654
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
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  • 44
    Publication Date: 2022-02-25
    Description: Bagnoli Coroglio is an urban district of the City of Naples (South Italy), which fronts the Tyrrhenian Sea for nearly 3 km. It is part of the Campi Flegrei caldera, one of the most explosive volcanic areas in Europe. The need for redeveloping the site after the intense industrial activities of the twentieth century has prompted a remarkable research effort to investigate the pollution's degree, nature, and extent at both the land and seafloor. This article focuses on releasing thermal waters from a natural channel as a source of arsenic contamination in the Bagnoli marine sediments; the thermal waters originate from the nearby Agnano hot-springs and have been conveying artificially to the track since the mid-XIX century. As a first part of the outcomes, the work describes the flow regime that characterizes the marine area. The analysis has been conducted via numerical simulations carried out with the software package Delft3D, developed by Deltares, which employs dynamically interfacing modules to account for wave propagation, generation of currents, and presence of coastal structures. Climatic inputs to the software (waves, winds, and tide) have specifically been gathered and analyzed within this research. The numerical study has permitted to furnish, for the first time, a clear and systematic view of the hydrodynamic forcings that characterize the area under investigation. In particular, a leading role in the transport of pollutants could be played by rip current systems, whose characteristics vary with climate intensity (waves and wind) and coastal structures characteristics. Due to its inherently dynamic nature, the proposed approach seems especially desirable in situations where different contamination sources are compared. As such, it could be successfully applied to other sites also.
    Description: Published
    Description: 146811
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Anthropogenic contamination sources; Marine circulation; Numerical modeling; Pollutants advection; Rip currents; Seabed contamination by arsenic
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
    Publication Date: 2022-02-25
    Description: We investigated the calcareous nannofossil biostratigraphy and magnetostratigraphy of middle Eocene – lower Oligocene sediments from ODP Hole 709 C, equatorial Indian Ocean. The new bio-magnetostratigraphic analyses have resulted in an accurate biochronology of the interval span- ning Chrons C20r (middle Eocene) to C12r, in which 29 bioevents were investigated, in a 12 myr interval. The magnetostratigraphic signal is less clear across the Eocene-Oligocene transition (EOT) but becomes more reliable at the top of Chron C13n to Chron C12r (early Oligocene). Quantitative analyses of calcareous nannofossil as- semblages allowed recognition of the Middle Eocene Climatic Optimum (MECO) and the long cooling trend leading to the glacial state starting in the early Oligocene. We identify two hiatuses, in the lower middle Eocene and across the Eocene-Oligocene Transition (EOT). Across the latter unconformity, a major transition from oligotrophic to eutrophic favoring nannofossil taxa highlights the enhanced sea surface nutrient availability during the transition to the early Oligocene glacial system. Finally, a late Oligocene warming event is recorded at this site by the increase in calcareous nannofossil taxa that preferred warm water.
    Description: Published
    Description: 102051
    Description: 5A. Ricerche polari e paleoclima
    Description: JCR Journal
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  • 46
    Publication Date: 2022-02-11
    Description: This investigation presents for the first time the seasonal and solar cycle variations of the daytime F-layer multiple stratifications (F3 and F4 layers) near the southern crest of the EIA in two different longitudinal sectors of South America. To perform the study, the ionograms recorded from 2007 to 2015 at Sao Jose dos Campos (23.2° S, 45.9° W), Brazil (eastern sector), and at Tucuman (26.9° S, 65.4° W), Argentina (western sector), are considered. Both sites present a frequency of occurrence of the F3 and F4 layers which is directly proportional to the solar activity, and an annual variation with a maximum in spring/summer and a minimum in autumn/winter. The main result that came out from the analysis is that the frequency of occurrence of the F3 and F4 layers is higher in the western sector than in the eastern sector, and this could be attributed to a different gravity waves activity characterizing the two longitudinal sectors.
    Description: Published
    Description: 59-70
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
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  • 47
    Publication Date: 2022-02-10
    Description: Muography represents a recent and innovative tool for investigating the interior of active volcanoes. However, when dealing with frequently erupting open-vent volcanoes such as Stromboli, any result should take into con- sideration the structural and morphology changes caused by the eruptive activity. This may cause either summit collapses by magma withdrawal, or morphology growth by the accumulations of a fallout from the explosive activity, or more often a combination of both. In this chapter, we present an integration of various techniques, comprising muography and digital elevation model reconstruction, together with GBInSAR ground deformation and volcano seismicity, to reconstruct the geometry of the shallow magma supply system of the volcano and its changes in time. We show how muography can display the interior of the volcano as well as its outer growth, being sensitive to all volume changes that occurred between the framed surface and the detector. This was discovered in Stromboli by comparing digital topography in the interval between 2010 and 2012, when the rapid growth of the volcano summit by the accumulation of ballistic products in the area between the crater zone and the muon detec- tor occurred. This deposit, together with the filling in of the graben-like depression, formed during the 2007 eruption, by fallout during the persistent explosive activity, contributed to generating a remarkable anomaly in the summit area of the volcano visualized by muography. In addition, the shallow feeding system of the volcano was surveyed by GBInSAR and seismicity, which allowed us to reconstruct its path up to a depth of a few hundred meters.
    Description: Published
    Description: 75-91
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Keywords: Stromboli volcano ; Shallow supply system ; Muography of active volcanoes
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 48
    Publication Date: 2022-02-07
    Description: We address the potential for methane to exist in the subsurface of Mars, focusing on its generation, accumulation in sealed traps, and seepage to the atmosphere. We discuss two abiotic processes that could have produced subsurface methane, even if life never developed on the planet. Compared to Earth, accumulations of methane on Mars are likely to be limited, and those that are present may be better sealed by the thick and planetwide cryosphere. Releases are thus expected to be minor and episodic. We emphasize the importance of long-term, continuous monitoring of predicted release sites, as limited, episodic releases could be easy to miss. Moreover, we note that numerous scenarios of methane fluxes from terrestrial analogs may explain non-detections by the ExoMars Trace Gas Orbiter (TGO), as they can produce atmospheric concentrations below the TGO limit of detection. Our work does not negate the potential for meteoric/cometary sources of methane, but it does illustrate the strength of the case for subsurface sourcing. Finally, we provide a map of potential locations of release and discuss remaining uncertainties and a path forward.
    Description: Published
    Description: 149-174
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 49
    Publication Date: 2022-02-14
    Description: East Java is characterised by a complex interaction of volcanic and tectonic processes and it is marked by isolated eruptive centres scattered across the back-arc sedimentary basins. In 2006 a large sediment hosted geothermal system named Lusi, pierced the Kendeng basin in East Java and since then it continues in a relentless eruption of mud breccia. To investigate the spatial and structural relationships between the volcanic arc and the back-arc domains, we perform a local earthquake tomography. The inversion of regional earthquakes recorded by our seismic network (for about two years) shows sharp Vp and Vp/Vs transitions. We observe a marked reduction of P-wave velocities and a high Vp/Vs ratio in the back-arc basins. Our study highlights a clear connection between the plumbing system of the volcanic arc and the northern sedimentary province. We propose a conceptual model suggesting that magmas and hydrothermal fluids may migrate from the middle to the upper crust into the sedimentary basins capitalising on existing thrust faults. Such low angle faults, promoted by the compressional regime of the region, link the magmatic domain to the northern sedimentary provinces. This process may represent the early phase of volcanic arc migration when magma-derived fluids are focused into fractured and permeable geological structures. Our conceptual model would not only help to understand the occurrence of the abundant mantle-derived fluids sampled across the back-arc, but it is also consistent with the occurrence of isolated magmatic and hybrid systems piercing across sedimentary environments in the back-arc of Java.
    Description: Published
    Description: 117258
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 50
    Publication Date: 2022-02-14
    Description: Archaeological sites are extremely vulnerable to the impacts of weather-related events, which may lead to irreparable damages to cultural heritage. Here an assessment of the debris-flow hazard for the UNESCO site of Roman Villa del Casale (Italy) is carried out, through a combination of historical analyses, field surveys, geomorphological and hydrological investigations and two-dimensional hydraulic numerical modelling, all performed at river catchment scale. Historical analyses reveal that the site has been hit by several landslides in the far and recent past. This is presently confirmed by the high level of exposure to the impact of rain-triggered debris-flow events, due to the position of the Villa at a closure section of the related river basin and to the hydro- geomorphological characteristics of the basin itself. By applying the proposed approach, a scenario analysis is carried out. Results allow one to highlight the dynamics of the impact of debris flows, thanks to space and time- dependent maps about deposition areas, water depth and speed values, and to identify the most vulnerable archaeological elements within the study site. The numerical simulations are also used to test the efficiency of the existing hydraulic defense systems and to support the implementation of an early warning system for the site protection. Here, we also synthetize the design of the architecture of the wireless monitoring network, the sensor technology adopted to develop an effective real time environmental monitoring system and management plat-form, to construct a Wireless Sensor Network (WSN) - early warning and reporting system, which can be applied as a prevention measure.
    Description: Published
    Description: 102509
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Keywords: Hydraulic risk, Archaeological excavation, Cultural heritage, WSN Monitoring, EWS Scenario analysis ; 03.02. Hydrology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 51
    Publication Date: 2022-02-14
    Description: Como historic centre, located at the SW branch of Lake Como (northern Italy), is prone to subside because of a thick sequence of late Pleistocene to Holocene glacio-lacustrine, palustrine and alluvial sediments in the subsoil. After the 1950s, the combination of natural causes and anthropogenic activities amplified subsidence-induced differential settlements at building foundation depths, resulting in damage on the superstructures. This work presents the first subsidence vulnerability analysis of the historic buildings in Como city centre by combining hydrogeological and stratigraphic features, in situ damage investigations, and remote sensing Synthetic Aperture Radar (SAR) data acquired by Cosmo-SkyMed mission. First, the relationships between local hydrogeological features and vertical displacements retrieved by SAR Interferometry (InSAR) analysis were qualitatively assessed. This highlighted that cumulative vertical InSAR-derived settlements have a stronger linear correlation with the groundwater level rather than the thickness of compressible soil units at the city scale. The largest vertical displacements are located in the NW sector of the city centre and along the shore of Lake Como, where they remark the pre-Roman shoreline. Then, the cause-effect relationships between building damage severity and Subsidence-Related Intensity (SRI) parameters were investigated using a probabilistic approach based on empirical fragility curves. To this aim, two InSAR-derived SRI parameters were tested for both masonry and reinforced concrete buildings: differential settlements and relative rotations. The former resulted to relate better to distinct damage levels in Como historic centre. The analyses performed can contribute to the management of the inestimable architectural and cultural heritage of Como historic centre.
    Description: Published
    Description: 102115
    Description: 5IT. Osservazioni satellitari
    Description: JCR Journal
    Keywords: Subsidence of Como urban area
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 52
    Publication Date: 2022-02-14
    Description: Microplastic presence in benthic marine systems is a widely discussed topic. The influence of the natural matrix on microplastic distribution within the sedimentary matrix is often overlooked. Marine sediments from the western inner Oslofjord, Norway, were investigated for temporal trends, with a particular focus on the relationship between sediment grain-sizes and microplastic distribution. Density separation, optical microscopy and chemical validation were used to categorize microplastics. Microplastic concentrations ranged from 0.02 to 1.71 MPs g − 1 dry weight (dw). Fibres were the most common (76%), followed by fragments and films (18%, 6%). Common polymers were polyesters (50%), polypropylene (18%), polymethylmethacrylate (9%), rayon and viscose (5%) and elastane (4%). Microplastics appear to accumulate preferentially according to their morphology and polymer type in certain sediment grain-sizes. Microplastics inputs to the Oslofjord appear to derive from a wastewater treatment plant in the vicinity. Although, the redistribution of microplastics within the fjord needs further investigation.
    Description: This project was supported by the Norwegian Institute for Water Research (NIVA) and the Erasmus+ Programme (EU).
    Description: Published
    Description: 113076
    Description: 7SR AMBIENTE – Servizi e ricerca per la società
    Description: JCR Journal
    Keywords: Accumulation ; Plastic pollution ; Canonical correspondence analysis (CCA) ; Wastewater treatment plant (WWTP) ; Sediment core ; FT-IR ; Microplastics ; Marine sediments
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 53
    Publication Date: 2022-02-14
    Description: Magnetic skyrmions are emerging as key elements of unconventional operations having unique properties such as small size and low current manipulation. In particular, it is possible to design skyrmion-based neurons and synapses for neuromorphic computing in devices where skyrmions move along the current direction (zero skyrmion Hall angle). Here, we show that, for a given graph, skyrmions can be used in optimization problems facing the calculation of the shortest path. Our tests show a solution with the same path length as computed with Algorithm. In addition, we also discuss how skyrmions act as positive feedback on this type of problem giving rise to a self-reinforcement of the path which is a possible solution.
    Description: Published
    Description: 167977
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: 7SR AMBIENTE – Servizi e ricerca per la società
    Description: JCR Journal
    Keywords: Physics - Mesoscopic Systems and Quantum Hall Effect; Physics - Mesoscopic Systems and Quantum Hall Effect
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 54
    Publication Date: 2022-02-11
    Description: In this study we present a procedure for the topographic classification of Italy, taking advantage of existing high resolution digital elevation models (DEM), with the support of routines embedded in Geographic Information Systems. The proposed method is based on morphometric analyses of a DEM, allowing for hilltop ridge detection, slope computation, identification of reliefs with potential topographic site effects, and topographic classification according to the indications of the current European and Italian seismic codes. The developed procedure can be applied worldwide and has a potential engineering interest for a fast and accurate topographic classification of a site, for both scientific and application purposes. The topographic classification of Italy is tested on several well known cases of topographic amplification and it is adopted for the topographic classification of Italian accelerometric stations.
    Description: The study has partially benefited from funding provided by the Italian Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile (DPC)—Agreement B2, DPC-INGV. This paper does not necessarily represent DPC official opinions and policies.
    Description: Published
    Description: 106848
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: DEM ; Topographic classification ; EC8 ; NTC18 ; GIS ; Morphometric analyses
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 55
    Publication Date: 2022-02-11
    Description: Fluids supplied by stored magma at depth are causal factors of volcanic unrest, as they can cause pressurization/ heating of hydrothermal systems. However, evidence for links between hydrothermal pressurization, CO2 emission and volcano seismicity have remained elusive. Here, we use recent (2010−2020) observations at Campi Flegrei caldera (CFc) to show hydrothermal pressure, gas emission and seismicity at CFc share common source areas and well-matching temporal evolutions. We interpret the recent escalation in seismicity and surface gas emissions as caused by pressure-temperature increase at the top of a vertically elongated (0.3–2 km deep) gas front. Using mass (steam) balance considerations,we showhydrothermal pressurization is causing energy transfer from the fluids to the host rocks, ultimately triggering low magnitude earthquakes within a seismogenetic volume containing the hydrothermal system. This mechanism is probably common to other worldwide calderas in similar hydrothermal activity state.
    Description: MIUR project n. PRIN2017-2017LMNLAW“Connect4Carbon”
    Description: Published
    Description: 107245
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: CO2 emission ; Campi Flegrei ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
    Publication Date: 2022-02-03
    Description: This work presents the first 3D geological model of the Rome coastal area that integrates available subsurface geological, stratigraphic and geophysical data with surface geochemical data obtained both from the literature and new surveys. The model provides new insights into the stratigraphic and tectonic setting of the area and the geological factors controlling both natural and human-induced gas emissions. This sector of the Italian Tyrrhenian margin has been historically affected by natural emissions of deep CO2 and thermogenic CH4, stored in permeable layers but with local migration to the surface along buried normal faults. In addition to natural processes, human activities can also cause leakage and serious health risks, such as the abrupt gas release in August 2013, that was triggered by borehole drillings near the Rome international airport. The presented 3D reconstruction unveils the link between faults, stratigraphy, lithology and the distribution of the soil gas anomalies. It provides information about the depth of the reservoir that can potentially trap endogenous gases, and the location and geometry of the main faults along which the gas migrates towards the surface. Furthermore, reconstruction of the distribution and thickness of important clay layers better constrains the low permeable areas that prevent gas escape. The 3D model, coupled with the geochemical information, can serve as a useful tool for the local administration to perform land-use planning and manage the local geological and degassing hazards that affect this highly urbanized area near Rome. Furthermore, we estimate that the large amount of CO2 broadly released in the area also provides a contribution to the budget of natural greenhouse gases in the atmosphere.
    Description: Published
    Description: 106527
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: 3D geological model ; Soil gas ; Active faults ; Surface degassing ; Geological hazards ; Tiber delta ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 57
    Publication Date: 2022-02-02
    Description: Ion temperature data recorded by Millstone Hill incoherent scatter radar (42.61 N, 288.51 E) over four full solar cycles (from 1970 to 2018) are analyzed to depict its climatological behavior in the range of altitudes between 100 and 550 km. The ion temperature dependencies on altitude, local time, month of the year, and solar activity level are studied through a climatological analysis based on binning and boxplot representation of statistical values. Binned observations of ion temperature are compared with International Reference Ionosphere (IRI) modeled values (IRI-2016 version). This comparison reveals several shortcomings in the IRI modeling of the ion temperature at ionosphere altitudes, in particular for the altitudinal, diurnal, seasonal, and solar activity description. The main finding of this study is that the overall IRI overestimation of the ion temperature can be probably ascribed to the long-term ionosphere cooling. Moreover, the study suggests that the IRI ion temperature model needs to implement the seasonal and solar activity dependence, and introduce a more refined diurnal description to allow multiple diurnal maxima seen in observations. The IRI ion temperature anchor point at 430 km is investigated in more detail to show how also a better description of the altitude dependence is desirable for modeling purposes. Some hints and clues are finally given to improve the IRI ion temperature model.
    Description: Published
    Description: 2186-2203
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 58
    Publication Date: 2022-02-02
    Description: TITIPy (Topside Ionosphere Turbulence Indices with Python) is a stand-alone Python tool developed for the calculation and mapping of RODI, ROTI, and ROTEI indices, for the characterization of the turbulent state of the topside ionosphere. Data gathered by Langmuir Probes and Precise Orbit Determination antennas on-board ESA Swarm satellites constellation are used to calculate topside ionosphere indices with a high time rate and a global coverage. From the study of these topside indices, information on physical mechanisms involved in the formation of small-scale irregularities (both spatial and temporal) can be drawn, particularly at high and low latitudes. TITIPy provides outputs as time series of calculated indices in text files, and figures as maps in geographic and magnetic coordinates. TITIPy is particularly suited for the investigation of the topside ionosphere irregularities, and for the identification of peculiar spatial and temporal patterns. The paper describes the TITIPy design and code workflow along with a detailed explanation of RODI, ROTI, and ROTEI indices calculation. Furthermore, an example of application based on data collected during the St. Patrick 2015 geomagnetic storm is also shown. TITIPy is open-source and freely downloadable at https://github.com/pignalberi/TITIPy.
    Description: Published
    Description: 104675
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 59
    Publication Date: 2022-02-11
    Description: Prior to the 2018 lower East Rift Zone (ERZ) eruption and summit collapse of Kīlauea Volcano, Hawai‘i, continuous gravimeters operated on the vent rims of ongoing eruptions at both the summit and Pu‘u ‘Ō‘ō. These instruments captured the onset of the 2018 lower ERZ eruption and the effects of lava withdrawal from both locales, providing constraints on the timing and style of activity and the physical properties of the lava lakes at both locations. At the summit, combining gravity, lava level, and a three-dimensional model of the vent indicates that the upper ∼200 m of the lava lake had a density of about 1700 kg m−3, slightly greater than estimates from 2011–2015 and possibly indicating a gradual densification over time. At Pu‘u ‘Ō‘ō, gravity and vent geometry were used to model both the density and the rate of crater collapse, which was unknown owing to a lack of visual observations. Results suggest the withdrawal of at least m3 of lava over the course of two hours, and a material density of 1800–1900 kg m−3. In addition, gravity data at Pu‘u ‘Ō‘ō captured a transient decrease and increase about an hour prior to crater collapse and that was probably related to a small, short-lived fissure eruption on the west flank of the cone and possibly to dike intrusion beneath Pu‘u ‘Ō‘ō. The fissure was the first event in the subsequent cascade that ultimately led to the extrusion of over 1 km3 of lava from lower ERZ vents, collapse of the summit caldera floor by more than 500 m, and the destruction of over 700 homes and other structures. These results emphasize the importance of continuous gravity in operational monitoring of active volcanoes.
    Description: Published
    Description: 117003
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 60
    Publication Date: 2022-02-11
    Description: Extensive geophysical and geodetic measurements were carried out to evaluate the groundwater aquifer, trace the basement relief, as well as detect the igneous intrusions and structural elements (mainly faults) that affect the occurrence of groundwater in the study area. The fieldwork included resistivity sounding, a geomagnetic survey, and Global Positioning System measurements. The magnetic results showed the presence of a group of main faults in East-west trend at the western part of the area and major fault at the northern part of the area of NW-SW trend. The findings also showed the presence of two igneous rock intrusions located in the middle of the eastern part of the valley. Pronounced differences in the depths of basement rocks have been identified, ranging between 0 and 900 m from the surface. Both high horizontal movements and high shear strain rates have been found to be concentrated at the southeast of the study area and it was noted that high stress was accumulated along the main observed faults and at the main groundwater aquifers. The geoelectrical results confirmed the presence of two aquifers; a shallow aquifer (Quaternary aquifer) that narrows northwards and a Nubian sandstone aquifer, which considered the main aquifer. The Nubian sandstone aquifer carries groundwater in the region, which overlies the last geoelectric unit represented by the basement complex layer and geological structures affecting the potential availability of groundwater in the study area, as proved by the geomagnetic survey and stress accumulation.
    Description: Researchers Supporting Project number (RSP-2021/351), King Saud University, Riyadh, Saudi Arabia
    Description: Published
    Description: 101549
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: GPS ; stress ; strain ; geomagnetic ; geoelectric ; groundwater ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 61
    Publication Date: 2022-02-11
    Description: This work describes the data used in the EPSL research article "Quantifying strong seismic propagation effects in the upper volcanic edifice using sensitivity kernels". The dataset is generated in order to investigate to what extent the seismic signals recorded on volcanoes are affected by near surface velocity structure. Data were calculated using the computational spectral elements scheme SPECFEM2D, where the wave propagation beneath Mount Etna volcano, Italy, was simulated in both homogeneous and heterogeneous models. The heterogeneous model comprises a low-velocity superficial structure (top several hundred meters) based on the previously published studies. Several different source mechanisms and locations were used in the simulations. The seismic wavefield was "recorded" by 15 surface receivers distributed along the surface of the volcano. The associated sensitivity kernels were also computed. These kernels highlight the region of the velocity model that affects the recorded seismogram within a desired time window. The text files describing the velocity models used in the simulations are also provided. The data may be of interest to volcano seismologists, as well as earthquake seismologists studying path effects and wave propagation through complex media.
    Description: European Union Seventh Framework Programme (FP7/2007 2013) under the project NEMOH, grand agreement no. 289976.
    Description: Published
    Description: 106673
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Near surface velocity structure; Numerical simulations; Sensitivity kernels; Specfem2d; Volcanic edifice; Volcano seismic sources
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 62
    Publication Date: 2022-02-11
    Description: In volcanic environments, the correct interpretation of the signals recorded by a seismic station is critical for a determination of the internal state of the volcano. Those signals contain information about both the seismic source and the properties of the path travelled by the seismic wave. Therefore, understanding the path effect is necessary for both source inversions and geophysical investigation of the volcanoes' properties at depth. We present an application of the seismic adjoint methodology and sensitivity kernel analysis to investigate seismic wave propagation effects in the upper volcanic edifice. We do this by performing systematic numerical simulations to calculate synthetic seismograms in two-dimensional models of Mount Etna, Italy, considering different wave velocity properties. We investigate the relationship between different portions of a seismogram and different parts of the structural volcano model. In particular, we examine the influence of known near-surface low-velocity volcanic structure on the recorded seismic signals. Results improve our ability to understand path effects highlighting the importance of the shallowest velocity structure in shaping the recorded seismograms and support recent studies that show that, although long-period seismic events are commonly associated with magma movements in resonant conduits, these events can be reproduced without the presence of fluids. We conclude that edifice heterogeneities impart key signatures on volcano seismic traces that must be considered when investigating volcano seismic sources.
    Description: Published
    Description: 116683
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 63
    Publication Date: 2022-02-14
    Description: High-elevation plateaus that are positioned in between topographic barriers are common orogenic features in the South American continent, formed under a range of evolving environmental conditions. For example, in the central Andes (Bolivia-Argentina), the Puna-Altiplano is arid and endorheic with a poorly developed fluvial system, while in the northern Andes (Colombia) the Chiquinquirà and Tunja highlands are characterized by a humid equatorial exorheic fluvial system. In addition to a plateau-like low-relief surface at 2500 m, the landscape of the northern Eastern Cordillera and SantanderMassif (northern Colombia) displays a lower elevation (~1500m) low-relief landscape (Mesas) comprising river captures, windgaps, and a disconnected alluvial fan that collectively record a transient state. This configuration has been achieved through a combination of compressive deformation and sub-crustal processes. The compressive shortening started to occur in the Paleogene and is still active, whereas regional surface uplift related to slab flattening andmantlewedge hydration startedintheLateMiocene/Pliocene.To disentangle the crustal vs sub-crustal forcing and to investigate the relative timing of drainage network evolutionwe combine the analysis of topography, hydrography (river longitudinal profiles, morphometric parameters, drainage divide stability), knickpoint migration (celerity model), paleo-longitudinal profile modeling, satellite images, and field observations. In particular, we show that during the development of the low-relief Mesas landscape the older Chiquinquirà highland was a closed drainage and that the lower portion of the Suárez River flowed northward into the Bucaramanga depression forced by the Los Cobardes Anticline topographic barrier. The Suárez River collected waters from the southern SantanderMassif and the upper reach of the Chicamocha River, which was draining the Tunja highland. An abandoned windgap deposit on the eastern edge of the Mesa de Barichara suggests that the lower portion of the Chicamocha Riverwas not yet formed. Subsequent to the Chiquinquirà highland drainage opening, two main tributaries of the Magdalena River, the Lebrija and Sogamoso, captured the Suárez River in a short temporal sequence. A knickpoint celerity model allows us to date the Lebrija capture of the Bucaramanga depression at ~260–270 ka and the subsequent Sogamoso capture at 190–220 ka. Only during this final stage, the lowermost Chicamocha River section formed and the drainage network developed to its present configuration. Finally,we suggest that the early Cenozoic rift inversion has controlled the drainage network pattern and the late Miocene sub-crustal-induced surface uplift has driven the main fluvial network reorganization.
    Description: Published
    Description: 107847
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
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  • 64
    Publication Date: 2022-02-11
    Description: The evolution of volcanic activity observed at the New South East Crater (NSEC) and Voragine (VOR) between July 2019 and January 2020 has been deciphered by taking into account the changes of textures and chemical zoning of plagioclase and olivine crystals from the erupted lavas and tephra. The petrological observations have been integrated with analyses of the amplitude and source location of volcanic tremor and infrasound data. Characteristics of crystals erupted on July 2019 at the NSEC reflect protracted intrusions of magma into the mid-upper section of the plumbing system, approximately within 290–120 MPa, which acted as the main zone of magma accumulation and crystallization before the beginning of the eruptive activity. Textures and compositions of crystals erupted at VOR emphasize the beginning of volcanic activity driven by recharge/discharge phases that mostly affect the shallowest portion of the Mt. Etna plumbing system (〈40 MPa). At the end of 2019, mineral compositions and zoning patterns changed again in accordance with eruption dynamics. The observed changes reflect the transition from an early phase, between November and December 2019, characterized by substantial equilibrium during magma storage and transport toward higher disequilibrium conditions and eruptive frequency, in January 2020. This has been associated to episodes of deep replenishment of mafic magmas displacing the resident one. Diffusion chronometry applied to zoned olivines shows that most of the episodes of magma intrusion correlate temporally with changes in the features of both volcanic tremor and infrasonic events in terms of amplitude and source location, providing evidence that such geophysical signals are directly related to the magma dynamics in the upper plumbing system.
    Description: Published
    Description: 107350
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Keywords: 04.08. Volcanology
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  • 65
    Publication Date: 2022-02-14
    Description: Shallow water equations are widely used in the simulation of those geophysical flows for which the flow horizontal length scale is much greater than the vertical one. Inspired by the example of lava flows, we consider here a modified model with an additional transport equation for a scalar quantity (e.g., temperature), and the derivation of the shallow water equations from depth-averaging the Navier-Stokes equations is presented. The assumption of constant vertical profiles for some of the model variables is relaxed allowing the presence of vertical profiles, and it follows that the non-linearity of the flux terms results in the introduction of appropriate shape coefficients. The space discretization of the resulting system of hyperbolic partial differential equations is obtained with a modified version of the finite volume central-upwind scheme introduced by Kurganov and Petrova in 2007. The time discretization is based on an implicit-explicit Runge-Kutta method which couples properly the hyperbolic part and the stiff source terms, avoiding the use of a very small time step; the use of complex arithmetic increases accuracy in the implicit treatment of stiff terms. The whole scheme is proved to preserve the positivity of flow thickness and the stationary steady-states. Some numerical experiments are performed to validate the proposed method and to show the incidence on the numerical solutions of shape coefficients introduced in the model.
    Description: Published
    Description: 482-505
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Shallow water equations ; Viscous fluids ; Finite Volume ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 66
    Publication Date: 2022-02-11
    Description: In this work, a partitioned fluid-structure interaction solver is presented. Fluid flow problem is solved with time-discontinuous deforming domain stabilized space-time finite element method. Flow is computed with pressure primitive variables which permit to use the same numerical technique for both compressible and incompressible regimes. Elastic deformation of the structure is modelled in the Lagrangian frame of reference with Saint-Venant Kirchhoff and Neo-Hookean material models - both are non-linear and valid for large deformations. Structure equations are discretized with Galerkin finite element method for space and with generalized-alpha method for the time. Mesh motion is modelled with the elastic deformation method. An implicit algorithm is presented to couple the different solvers. The details are provided on the implementation of the solvers in parallel software. The numerical code is verified and validated on several compressible and incompressible flow benchmarks widely used in the literature. The results demonstrate that the developed solver successfully detects the accurate interaction between fluid and structure.
    Description: Published
    Description: 182-195
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 67
    Publication Date: 2022-02-11
    Description: The Tolhuaca hydrothermal system is one of the few attested geothermal resources in Chile. While recent investigations provided some insights into the depth and temperature of the geothermal reservoirs and the chemical and mineralogical evolution of the hydrothermal system, little is still known about the CO2 degassing of the system and the local and shallow control of fluid pathways. Here, we document the soil CO2 degassing and soil temperature distributions in the southern part of the Tolhuaca hydrothermal system and at one of its northern fumaroles, and provide a first estimate of its total CO2 release. The surveyed area is responsible for a total CO2 emission of up to 30 t d-1. Hydrothermal CO2 emissions (~ 4-27 t d-1) are mostly restricted to the thermal manifestations or generally distributed along NNW trending lineaments, sharing the same orientation as the volcanic vents and thermal springs and fumaroles. Hydrothermal CO2 fluxes, fumaroles and thermal springs are generally encountered in topographic lows, in close vicinity of streams and often in clay-rich pyroclastic units, highlighting a relation between landscape evolution and the activity of the hydrothermal system. We suggest that glacial unloading and incision of the stream inside the clay-rich units have likely enhanced locally the permeability, creating a preferential pathway for the migration of deeper fluid to the surface. As several hydrothermal systems in the Andes are found on the flank of volcanoes hosting glaciers, we propose that they could have had a similar development to that of the Tolhuaca hydrothermal system.
    Description: Published
    Description: 107316
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: CO2 emission ; Tolhuaca volcano
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 68
    Publication Date: 2022-02-14
    Description: Exposure to styrene is a major safety concern in the fibreglass processing industry. This compound is classified by the International Agency for Research on Cancer as a possible human carcinogen. Several types of analytical equipment exist for detecting volatile organic compounds (VOCs) in the atmosphere; however, most of them operate ex-situ or do not provide easy discrimination between different molecules. This work introduces an improved and portable method based on FTIR spectroscopy to analyse toxic gaseous substances in working sites down to a concentration of less than 4 ppm. Styrene and a combination of VOCs typically associated with it in industrial processes, such as acetone, ethanol, xylene and isopropanol, have been used to calibrate and test the methodology. The results demonstrate that the technique offers the possibility to discriminate between different gaseous compounds in the atmosphere with a high degree of confidence and obtain very accurate quantitative information on their concentration, down to the ppm level, even when different VOCs are present in a mixture.
    Description: Published
    Description: 122510
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Environmental sensors; Infrared spectroscopy; Volatile organic compounds
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 69
    Publication Date: 2022-02-14
    Description: This paper deals with the first geochemical data from an unexplored sector of the Cordón de Inacaliri Volcanic Complex (Central Andes, Chile). The site is located at ∼5,150-5,200 m a.s.l., inside the Pabelloncito graben where, at about 9 km NW of the studied area, the only currently working geothermal power plant of South America, named Cerro Pabellón, occurs. Diffuse soil CO2 and soil temperature measurements were carried out to unravel the structural control on the rising fluids and estimate the total CO2 output, the heat flow rate and the heat flux, aimed at assessing a preliminary evaluation of the geothermal potential of the area. The study area is characterized by a pervasive hydrothermal mineralogical alteration, CO2 flux values of up to ∼4,400 g m-2 d-1 and soil temperatures up to the boiling point of water at that altitude. All these features are likely related to an endogenous source. Spatial distribution of both soil CO2 flux and temperature depict an ENE-striking lineament, whose intersection with the NW-striking Pabelloncito graben forms a favourable structural setting for the discharge of hydrothermal fluids. The total CO2 output emission of the studied area (∼0.0179 km2) was ∼0.53 t d-1, with an associated discharge of steam of 6.45 t d-1 (CO2/H2O ratio = 0.08). An electric capacity potential of 1.08 MWe km-2 was computed from the heat flow rate and heat flux values. Our results suggest that this part of the Pabelloncito graben is an interesting geothermal prospect and a good candidate for further exploration studies.
    Description: Published
    Description: 101961
    Description: 1TR. Georisorse
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 70
    Publication Date: 2022-02-11
    Description: Grooves represent the evidence of tectonic activity that deformed Ganymede surface during its geologic evolution. In this work, we investigate the main characteristics of Ganymede's groove populations on four different areas located at the equatorial region of the satellite (Uruk Sulcus, Babylon Sulci, Phrygia Sulcus and Mysia Sulci). Specifically, we analyse i) the grooves length distribution to provide a framework for their evolution and ii) the grooves self-similar clustering to infer their vertical penetration inside Ganymede icy shell. For each dataset, we find that the grooves distribution is well fitted by an exponential-law and a power-law distribution depending on the structure length. This implies the presence of confined structures in a shallow layer of the icy crust (relatively shorter, exponentially-fitted structures) and crustal-scale structures that could theoretically reach the crust-ocean interface (relatively longer, power law-fitted structures). In addition, the existence of two exponential distributions for few datasets suggest that there could be two different system of structure confined within specific mechanical crust layers. The thickness of the penetrated icy shell is retrieved through the self-similar clustering analysis and ranges between 105 and 130 km for the examined datasets. This value agrees with independent estimates of the icy shell thickness, ranging between 80 and 150 km. Moreover, our results support the hypothesis that a large number of grooves penetrate the brittle icy crust, with sets of fractures vertically confined in different mechanical layers, while the penetration of few interconnected faults underlying longer grooves may interest the whole icy crust above the liquid ocean.
    Description: Published
    Description: 105140
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: GALILEAN SATELLITES ; DARK TERRAIN ; FAULT EVOLUTION ; TECTONICS ; PATTERNS GEOMETRY ; JUPITER
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 71
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    Unknown
    American Geophysical Union
    In:  EPIC3Paleoceanography and Paleoclimatology, American Geophysical Union, 37(2), pp. e2020PA003953, ISSN: 2572-4517
    Publication Date: 2022-02-15
    Description: Cenozoic climate changes have been linked to tectonic activity and variations in atmospheric CO2 concentrations. Here we present Miocene and Pliocene sensitivity experiments performed with the climate model COSMOS. The experiments contain changes with respect to paleogeography, ocean gateway configuration, and atmospheric CO2 concentrations, as well as a range of vertical mixing coefficients in the ocean. For the Mid-Miocene, we show that the impact of ocean mixing on surface temperature is comparable to the effect of the possible range in reconstructed CO2 concentrations. In combination with stronger vertical mixing, relatively moderate CO2-concentrations of 450 ppmv enable global mean surface, deep-water and meridional temperature characteristics representative of Mid-Miocene Climatic Optimum (MMCO) reconstructions. The Miocene climate shows a reduced meridional temperature gradient and reduced seasonality. In the case of enhanced mixing, surface and deep ocean temperatures show significant warming of up to 5-10°C and an Arctic temperature anomaly of more than 12°C. In the Pliocene simulations, the impact of vertical mixing and CO2 is less important for the deep ocean, which we interpret as a different sensitivity dependence on the background state and mixed layer dynamics. We find a significant reduction in surface albedo and effective emissivity for either a high level of atmospheric CO2 or increased vertical mixing. Our mixing sensitivity experiments provide a warm deep ocean via ocean heat uptake. We propose that the mixing hypothesis can be tested by reconstructions of the thermocline and seasonal paleoclimate data indicating a lower seasonality relative to today.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 72
    facet.materialart.
    Unknown
    Elsevier
    In:  EPIC3Journal of Sea Research, Elsevier, 187, pp. 102245, ISSN: 13851101
    Publication Date: 2022-07-15
    Description: Foraminifera nourishing on fresh organic matter often exhibit an epibiotic or even an epizoic lifestyle. This study investigates the colonization of sponges by foraminifera. For this purpose, 12 siliceous sponges of different genera (Asconema, Geodia, Lissodendoryx and Schaudinnia) and order Haplosclerida were collected in 2018 with a ROV in water depths of 223 to 625 m in the Norwegian-Greenland Sea. Sponges were stained with a Rose Bengal/ ethanol mixture to allow a differentiation between foraminifera that had been recently alive and empty tests. Each sponge sample contained 3–42 dead and 1–10 living foraminiferal individuals per cm3 and summarizing up to 78 different taxa on one single sponge (Geodia phlegraei). Even on Geodia barretti, which is able to release barrettin (an alkaloid) to avoid colonialization by other organisms, living foraminiferal individuals (1 ind./cm3) were observed. The highest foraminiferal densities (living and dead individuals) were recorded on Haplosclerida sp. (49 ind./cm3) and Geodia sp. (45 ind./cm3). The lowest densities of foraminifera were found on G. barretti (3–14 ind./cm3) and on Lissodendoryx complicata (9 ind./cm3). The foraminiferal diversity ranges from 7.04 to 17.38 for Fisher α and from 2.40 to 3.33 (Shannon-Wiener (H)S). The highest diversity was found on G. phlegraei and the lowest one on L. complicata. This study is highlighting the ecosystem engineering role of sponges providing niche habitats for a high number of foraminifera.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed , info:eu-repo/semantics/article
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  • 73
    Publication Date: 2022-07-14
    Description: Forest destruction by ‘a‘ ̄a lava flow is common. However, mechanical and thermal interactions between the invading lava and the invaded forest are poorly constrained. We complete mapping, thermal image and sample analyses of a channel-fed ‘a‘a ̄ lava flow system that invaded forest on the NE flank of Mt. Etna (Italy) in 2002. These lava flows destroyed 231,000 trees, only 2% of which are still visible as felled trunks on the levees or at the channel-levee contact. The remaining 98% were first felled by the flow front, with the trunks then buried by the flow. Rare tree molds can be found at the rubble levee base where trees were buried by avalanching hot breccia and then burnt through, with a time scale for total combustion being a few days. Protruding trunks fell away from the flow, if felled by blocks avalanching down the levee flank, or became aligned with the flow if falling onto the moving stream. Estimated cooling rates (0.1–5.5 ◦C km− 1) are normal for well-insulated ‘a‘a ̄ flow, suggesting no thermal interaction. We find the highest phenocryst concentrations (of 50–60%, above an expected value of 30–40%) in low velocity (〈0.5 m s− 1) locations. These low velocity zones are also characterized by high trunk concentrations. Thus, the common factor behind crystal and trunk deposition is velocity. That is, when the lava slows down, crystal settling occurs and trunks are preferentially deposited. Thus, although we find no thermal or textural effects due to the presence of the forest, we do find mechanical and environmental in- teractions where the trees are consumed to become part of the flow.
    Description: This research was financed by the Agence National de la Recherche through the project LAVA (Program: DS0902 2016; Project: ANR-16 CE39-0009). We very much thank Sean I. Peters and an anonymous reviewer for their extremely constructive advice and support. This is ANR-LAVA contribution no. 23 and Laboratory of Excellence ClerVolc contribution no. 552.
    Description: Published
    Description: 107621
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: Channelized ‘a‘ ̄a lava flow ; thermal imagery ; lava flows ; 2002-03 eruption ; forest destruction ; tree molds ; Etna volcano ; cooling rates ; Interaction lava and trees ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 74
    Publication Date: 2022-06-06
    Description: Magmatic and sub-solidus fabrics in intrusive rocks are frequently used to infer the relative timing of deformation with respect to magma emplacement and cooling. Here, we describe the relationships between strain and fabric development in leucogranite sheets (pegmatite, aplite) emplaced into shear zones that localized post-thermal peak deformation in the contact aureole of an upper crustal pluton (〈0.2 GPa) on the Island of Elba, Italy. The leucogranite sheets present igneous, mylonitic, and cataclastic fabrics. Detailed meso- and microscopic structural analysis suggests that the dykes emplaced in the shear zones behaved as competent, rigid bodies during mylonitic deformation of the host rocks. Thermal modelling indicates that emplacement and cooling of the sheets occurred very rapidly (a few days to years) compared to typical tectonic strain rates and strain accumulation timescales in the host rocks. Such a fast cooling does not allow melt or magma-induced thermal softening in the host rocks during deformation. The development of mylonitic and cataclastic fabrics in the dykes was controlled by the localized activation of fluid-controlled reaction softening mechanisms (mylonitic fabric) and embrittlement during cooling in sites of high-strain (cataclastic fabric). We show that a broad spectrum of fabrics can form in igneous sheet intrusions emplaced at the same time and crustal level. The coexistence of isotropic (non-foliated igneous) versus anisotropic (mylonitic and cataclastic) fabrics in igneous sheet intrusions should therefore be evaluated in terms of tectonic strain rates, cooling rates, thermal state of the host, distribution of heterogeneous strain, and activation of strain softening mechanisms. Our observations highlight that the concepts of pre-, syn-, late- and post-tectonic fabrics in intrusive igneous rocks should be used with caution when interpreting relative timing relationships between deformation and magmatism.
    Description: Published
    Description: 104600
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Shear zones ; Igneous sheets Magma emplacementGranite deformationPegmatite ; Magma emplacement ; Granite deformation ; Pegmatite ; Elba Island ; Emplacement of a felsic dyke swarm during progressive heterogeneous deformation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 75
    Publication Date: 2022-06-16
    Description: Magnetic biomonitoring methodologies were applied at Villa Farnesina, Rome, a masterpiece of the Italian Renaissance, with loggias frescoed by renowned artists such as Raffaello Sanzio. Plant leaves were sampled in September and December 2020 and lichen transplants were exposed from October 2020 to early January 2021 at increasing distances from the main trafficked road, Lungotevere Farnesina, introducing an outdoor vs. indoor mixed sampling design aimed at assessing the impact of vehicular particulate matter (PM) on the Villa Loggias. The magnetic properties of leaves and lichens - inferred from magnetic susceptibility values, hysteresis loops and first order reversal curves - showed that the bioaccumulation of magnetite-like particles, associated with trace metals such as Cu, Ba and Sb, decreased exponentially with the distance from the road, and was mainly linked to metallic emission from vehicle brake abrasion. For the frescoed Halls, ca. 30 m from the road, the exposure to traffic-related emissions was very limited or negligible. Tree and shrub leaves of the Lungotevere and of the Villa's Gardens intercepted much traffic-derived PM, thus being able to protect the indoor cultural heritage and providing an essential conservation service. It is concluded that the joint use of magnetic and chemical analyses can profitably be used for evaluating the impact of particulate pollution on cultural heritage within complex metropolitan contexts as a preventive conservation measure.
    Description: Published
    Description: 153729
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Keywords: Brake wear; Cultural heritage; Lichen transplants; Magnetic biomonitoring; Preventive conservation; Traffic-related particulate matter
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 76
    Publication Date: 2022-06-09
    Description: Near-continuous monitoring both of gas emissions (CO2, CH4 and H2S) and of water temperature at Santa Venera al Pozzo thermal springs (SE foot of Mt. Etna volcano, Sicily, Italy) was conducted from December 2017 to April 2019, using a novel and cheaper Chromatography Monitoring System (CMS) coupled with a water temperature sensor. The results showed methane as predominant gas and temporal changes in gas concentrations that were in part due to daily fluctuations, which caused small amplitude variations, and in part due to non-environmental causes. These latter were correlated with the occurrence of strong earthquakes and slow tectonic events related to magmatic intrusions, but not with input of magmatic gases into the thermal aquifer, given the nonmagmatic origin of all monitored gases. Methane spikes were observed during many volcano-tectonic events and call for a deep source of this gas. H2S was detected only during the strongest local tectonic events, including a Mw 4.9 earthquake, suggesting that this gas has a common origin as CH4 (i.e., mixing between microbial and thermogenic gas), but it is released only when tectonic stress is applied for sufficiently long periods as to cause H2S oversaturation in the hydrothermal aquifer. Water temperature decreases were also observed immediately after the two strongest earthquakes in the area, which helped us produce a comprehensive model to explain the observed geochemical variations. Our approach allowed revealing the great sensitivity of gases such as CH4 and especially H2S to tectonic stress, thus making them valuable indicators of impending strong tectonic or volcanotectonic events.
    Description: Published
    Description: 229388
    Description: 9T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismiche
    Description: JCR Journal
    Keywords: Earthquakes ; Volcanic activity ; Geothermal systems ; Fluids ; Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 77
    Publication Date: 2022-05-24
    Description: The assessment of potential radon-hazardous environments is nowadays a critical issue in planning, monitoring, and developing appropriate mitigation strategies. Although some geological structures (e.g., fault systems) and other geological factors (e.g., radionuclide content, soil organic or rock weathering) can locally affect the radon occurrence, at the basis of a good implementation of radon-safe systems, optimized modelling at territorial scale is required. The use of spatial regression models, adequately combining different types of predictors, represents an invaluable tool to identify the relationships between radon and its controlling factors as well as to construct Geogenic Radon Potential (GRP) maps of an area. In this work, two GRP maps were developed based on field measurements of soil gas radon and thoron concentrations and gamma spectrometry of soil and rock samples of the Euganean Hills (northern Italy) district. A predictive model of radon concentration in soil gas was reconstructed taking into account the relationships among the soil gas radon and seven predictors: terrestrial gamma dose radiation (TGDR), thoron (220Rn), fault density (FD), soil permeability (PERM), digital terrain model (SLOPE), moisture index (TMI), heat load index (HLI). These predictors allowed to elaborate local spatial models by using the Empirical Bayesian Regression Kriging (EBRK) in order to find the best combination and define the GRP of the Euganean Hills area. A second GRP map based on the Neznal approach (GRPNEZ) has been modelled using the TGDR and 220Rn, as predictors of radon concentration, and FD as predictor of soil permeability. Then, the two GRP maps have been compared. Results highlight that the radon potential is mainly driven by the bedrock type but the presence of fault systems and topographic features play a key role in radon migration in the subsoil and its exhalation at the soil/atmosphere boundary.
    Description: Published
    Description: 152064
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Euganean Hills ; Geogenic Radon Potential ; Geostatistics ; Natural radioactivity ; Radon ; Regression kriging ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 78
    Publication Date: 2022-06-30
    Description: A full review of the 79 CE Plinian eruption of Vesuvius is presented through a multidisciplinary approach, exploiting the integration of historical, stratigraphic, sedimentological, petrological, geophysical, paleoclimatic, and modelling studies dedicated to this famous and devastating natural event. All studies have critically been reviewed and integrated with original data, spanning from proximal to ultradistal findings of the 79 CE eruption products throughout the Mediterranean. The work not only combines different investigation approaches (stratigraphic, petrological, geophysical, modelling), but also follows temporally the 79 CE eruptive and depo sitional events, from the magma chamber to the most distal tephras. This has allowed us first to compile a full database of all findings of those deposits, then to relate the products (the deposits) to the genetic thermo mechanical processes (the eruption), and lastly to better assess both the local and regional impacts of the 79 CE eruption in the environment. This information leads to a number of open issues (e.g., regional environmental impact vs. local pyroclastic current impact) that are worthy of further investigations, although the 79 CE eruption of Vesuvius is one of the best studied eruptions in volcanology. The structure of the work follows three macro-categories, the historical aspects, the products, and the processes of the 79 CE eruption. For each investigation approach (from stratigraphy to modelling), all dedicated studies and original data are discussed. The open issues are then synthesized in the discussion under a global view of Plinian eruptions, from the magma setting to its dispersion as pyroclasts flowing on the surface vs. falling from the volcanic plume. In this way, a lesson from the past, in particular from the well-studied 79 CE eruption of Vesuvius, will be of help for a better synchronization of processes and products in future developments. Lastly, various aspects for volcanic hazard assessment of Plinian eruptions are highlighted from the tephra distribution and modelling points of view, as these large natural phenomena can have a larger impact than previously thought, also at other active volcanoes.
    Description: Published
    Description: 104072
    Description: 1V. Storia eruttiva
    Description: 4V. Processi pre-eruttivi
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: 79 CE eruption ; Vesuvius ; Plinian eruption ; Pompeii ; Multidisciplinary approach ; Pyroclastic succession ; Pyroclastic currents ; 79 CE tephra dispersal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
    Publication Date: 2022-09-13
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nelson, R. K., Scarlett, A. G., Gagnon, M. M., Holman, A. I., Reddy, C. M., Sutton, P. A., & Grice, K. Characterizations and comparison of low sulfur fuel oils compliant with 2020 global sulfur cap regulation for international shipping. Marine Pollution Bulletin, 180, (2022): 113791, https://doi.org/10.1016/j.marpolbul.2022.113791.
    Description: The International Marine Organization 2020 Global Sulfur Cap requires ships to burn fuels with 〈0.50% S and some countries require 〈0.10% S in certain Sulfur Emission Control Areas but little is known about these new types of fuels. Using both traditional GC–MS and more advanced chromatographic and mass spectrometry techniques, plus stable isotopic, δ13C and δ2H, analyses of pristane, phytane and n-alkanes, the organic components of a suite of three 0.50% S and three 0.10% S compliant fuels were characterized. Two oils were found to be near identical but all of the remaining oils could be forensically distinguished by comparison of their molecular biomarkers and by the profiles of the heterocyclic parent and alkylated homologues. Oils could also be differentiated by their δ13C and δ2H of n-alkanes and isoprenoids. This study provides important forensic data that may prove invaluable in the event of future oil spills.
    Description: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. CMR and RKN were supported by the National Science Foundation (OCE-1634478 and OCE-1756242). GC × GC analysis support provided by WHOI's Investment in Science Fund.
    Keywords: International Maritime Organisation ; Biomarkers ; Fuel oil ; Heterocyclics ; GC × GC ; Mass spectrometry
    Repository Name: Woods Hole Open Access Server
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  • 80
    Publication Date: 2022-09-05
    Description: The chemical composition of gases emitted by active volcanoes reflects both magma degassing and shallower processes, such as fluid-rock hydrothermal interaction and mixing with atmospheric-derived fluids. Untangling the magmatic fluid endmember within surface gas emission is therefore challenging, even with the use of well-known magma degassing tracers such as noble gases. Here, we investigate the deep magmatic fluid composition at the Nisyros caldera (Aegean Arc, Greece) by measuring nitrogen and noble gas abundances and isotopes in naturally degassing fumaroles. Gas samples were collected from 32 fumarolic vents at water-boiling temperature between 2018 and 2021. These fumaroles are admixtures of magmatic fluids typical of subduction zones, groundwater (or air saturated water, ASW), and air. The N2, He, and Ar composition of the magmatic endmember is calculated by reverse mixing modeling and shows N2/He = 31.8 ± 4.5, N2/Ar = 281.6, d15N = +7 ± 3 ‰, 3He/4He = 6.2 Ra (where Ra is air 3He/4He), and 40Ar/36Ar = 551.6 ± 19.8. Although N2/He is significantly low with respect to typical values for arc volcanoes (1,000–10,000), the contribution of subducted sediments to the Aegean Arc magma generation is reflected by the positive d15N values of Nisyros fumaroles. The low N2/He ratio indicates N2-depletion due to solubility-controlled differential degassing of an upper-crustal silicic (dacitic/rhyodacitic) melt in a high-crystallinity reservoir. We compare our 2018–2021 data with N2, He, and Ar values collected from the same fumaroles during a hydrothermal unrest following the seismic crisis in 1996–1997. Results show additions of both magmatic fluid and ASW during this unrest. In the same period, fumarolic vents display an increase in magmatic species relative to hydrothermal gas, such as CO2/CH4 and He/CH4 ratios, an increase of 50 C in the equilibrium temperature of the hydrothermal system (up to 325 C), and greater amounts of vapor separation. These variations reflect an episode of magmatic fluid expulsion during the seismic crisis. The excess of heat and mass supplied by the magmatic fluid injection is then dissipated through boiling of deeper and peripheral parts of the hydrothermal system. Reverse mixing modeling of fumarolic N2-He-Ar has therefore important ramifications not only to disentangle the magmatic signature from gases emitted during periods of dormancy, but also to trace episodes of magmatic outgassing and better understand the state of the upper crustal reservoir.
    Description: Published
    Description: 68-84
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Noble gases ; Nitrogen isotope ; Mixing modeling ; Magmatic degassing ; High-crystallinity mush ; Caldera ; Unrest ; CO2 ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 81
    Publication Date: 2022-10-27
    Description: This paper is not subject to U.S. copyright. The definitive version was published in ten Brink, U. S., Vanacore, E. A., Fielding, E. J., Chaytor, J. D., Lopez-Venegas, A. M., Baldwin, W. E., Foster, D. S., & Andrews, B. D. Mature diffuse tectonic block boundary revealed by the 2020 southwestern Puerto Rico seismic sequence. Tectonics, 41(3), (2022): e2021TC006896, https://doi.org/10.1029/2021TC006896.
    Description: Distributed faulting typically tends to coalesce into one or a few faults with repeated deformation. The progression of clustered medium-sized (≥Mw4.5) earthquakes during the 2020 seismic sequence in southwestern Puerto Rico (SWPR), modeling shoreline subsidence from InSAR, and sub-seafloor mapping by high-resolution seismic reflection profiles, suggest that the 2020 SWPR seismic sequence was distributed across several short intersecting strike-slip and normal faults beneath the insular shelf and upper slope of Guayanilla submarine canyon. Multibeam bathymetry map of the seafloor shows significant erosion and retreat of the shelf edge in the area of seismic activity as well as slope-parallel lineaments and submarine canyon meanders that typically develop over geological time. The T-axis of the moderate earthquakes further matches the extension direction previously measured on post early Pliocene (∼〉3 Ma) faults. We conclude that although similar deformation has likely taken place in this area during recent geologic time, it does not appear to have coalesced during this time. The deformation may represent the southernmost part of a diffuse boundary, the Western Puerto Rico Deformation Boundary, which accommodates differential movement between the Puerto Rico and Hispaniola arc blocks. This differential movement is possibly driven by the differential seismic coupling along the Puerto Rico—Hispaniola subduction zone. We propose that the compositional heterogeneity across the island arc retards the process of focusing the deformation into a single fault. Given the evidence presented here, we should not expect a single large event in this area but similar diffuse sequences in the future.
    Description: 2022-08-08
    Keywords: Rupture of multiple faults ; Intra-arc deformation ; Earthquake-generated submarine canyon ; Anisotropic arc composition ; Caribbean seismic hazard
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  • 82
    Publication Date: 2022-10-27
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49(6), (2022): e2021GL095559, https://doi.org/10.1029/2021GL095559.
    Description: The valuable ecosystem services of salt marshes are spurring marsh restoration projects around the world. However, it is difficult to determine the final vegetated area based on physical drivers. Herein, we use a 3D fully coupled vegetation-hydrodynamic-morphological modeling system to simulate the final vegetation cover and the timescale to reach it under various forcing conditions. Marsh development in our simulations can be divided in three distinctive phases: A preparation phase characterized by sediment accumulation in the absence of vegetation, an encroachment phase in which the vegetated area grows, and an adjustment phase in which the vegetated area remains relatively constant while marsh accretes vertically to compensate for sea level rise. Sediment concentration, settling velocity, sea level rise, and tidal range each comparably affect equilibrium coverage and timescale in different ways. Our simulations show that the Unvegetated-Vegetated Ratio also relates to sediment budget in marsh development under most conditions.
    Description: This study was supported by the Department of the Interior Hurricane Sandy Recovery program (ID G16AC00455), NSF awards 1637630 (PIE LTER) and 1832221 (VCR LTER), and China Scholarship Council.
    Description: 2022-09-16
    Keywords: Marsh restoration ; Land reclamation ; COAWST ; Vegetation dynamics ; Phases of marsh development ; Expectance of marsh coverage
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  • 83
    Publication Date: 2022-10-27
    Description: Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(10),(2021): e2021JB022050, https://doi.org/10.1029/2021JB022050.
    Description: On-fault earthquake magnitude distributions are calculated for northern Caribbean faults using estimates of fault slip and regional seismicity parameters. Integer programming, a combinatorial optimization method, is used to determine the optimal spatial arrangement of earthquakes sampled from a truncated Gutenberg-Richter distribution that minimizes the global misfit in slip rates on a complex fault system. Slip rates and their uncertainty on major faults are derived from a previously published GPS block model for the region, with fault traces determined from offshore geophysical mapping and previously published onshore studies. The optimal spatial arrangement of the sampled earthquakes is compared with the 500-year history of earthquake observations. Rupture segmentation of the subduction interface along the Hispaniola-Puerto Rico Trench (PRT) fault and seismic coupling on the PRT fault appear to exert the primary control over this spatial arrangement. Introducing a rupture barrier for the Hispaniola-PRT fault northwest of Mona Passage, based on geophysical and seismicity observations, and assigning a low slip rate of 2 mm/yr on the PRT fault are most consistent with historical earthquakes in the region. The addition of low slip-rate secondary faults as well as segmentation of the Hispaniola and Septentrional strike-slip fault improves the consistency with historical seismicity. An important observation from the modeling is that varying the slip rate on the PRT fault and different segmentation scenarios result in significant changes to the optimal magnitude distribution on faults farther away. In general, optimal on-fault magnitude distributions are more complex and inter-dependent than is typically assumed in probabilistic seismic hazard analysis and probabilistic tsunami hazard analysis.
    Description: Funding for this study is from the U.S. Geological Survey Coastal and Marine Hazards and Resources Program.
    Description: 2022-04-11
    Keywords: Northern Caribbean ; Rupture forecast ; Combinatorial optimization ; Integer programming
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  • 84
    Publication Date: 2022-10-27
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molines, A. T., Lemière, J., Gazzola, M., Steinmark, I. E., Edrington, C. H., Hsu, C.-T., Real-Calderon, P., Suhling, K., Goshima, G., Holt, L. J., Thery, M., Brouhard, G. J., & Chang, F. Physical properties of the cytoplasm modulate the rates of microtubule polymerization and depolymerization. Developmental Cell, 57(4), (2022): 466-479.e6, https://doi.org/10.1016/j.devcel.2022.02.001.
    Description: The cytoplasm is a crowded, visco-elastic environment whose physical properties change according to physiological or developmental states. How the physical properties of the cytoplasm impact cellular functions in vivo remains poorly understood. Here, we probe the effects of cytoplasmic concentration on microtubules by applying osmotic shifts to fission yeast, moss, and mammalian cells. We show that the rates of both microtubule polymerization and depolymerization scale linearly and inversely with cytoplasmic concentration; an increase in cytoplasmic concentration decreases the rates of microtubule polymerization and depolymerization proportionally, whereas a decrease in cytoplasmic concentration leads to the opposite. Numerous lines of evidence indicate that these effects are due to changes in cytoplasmic viscosity rather than cellular stress responses or macromolecular crowding per se. We reconstituted these effects on microtubules in vitro by tuning viscosity. Our findings indicate that, even in normal conditions, the viscosity of the cytoplasm modulates the reactions that underlie microtubule dynamic behaviors.
    Description: This work was supported by grants to F.C. (NIH GM115185, NIH GM056836, NIH GM146438), to L.J.H. (American Cancer Society RSG-19-073-01-TBE, Pershing Square Sohn Cancer Award, Chan Zuckerberg Initiative, NIH GM132447 and NIH CA240765), to G.G. (JSPS KAKENHI 17H06471 and 18KK0202), to K.S. (UK’s Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/R004803/1) and to M.T. (ERC Consolidator Grant 771599). I.E.S. was supported by King’s College London through a LIDo (London Interdisciplinary Doctoral programme) iCASE studentship.
    Keywords: Cytoskeleton dynamics ; Microtubules ; Cytoplasm ; Crowding ; Viscosity ; Diffusion ; Density ; Rheology ; Mitosis ; Fission yeast Schizosaccharomyces pombe
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  • 85
    Publication Date: 2022-10-27
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Loescher, H., Vargas, R., Mirtl, M., Morris, B., Pauw, J., Yu, X., Kutsch, W., Mabee, P., Tang, J., Ruddell, B., Pulsifer, P., Bäck, J., Zacharias, S., Grant, M., Feig, G., Zheng, L., Waldmann, C., & Genazzio, M. Building a global ecosystem research infrastructure to address global grand challenges for macrosystem ecology. Earth’s Future, 10(5), (2022): e2020EF001696, https://doi.org/10.1029/2020ef001696.
    Description: The development of several large-, “continental”-scale ecosystem research infrastructures over recent decades has provided a unique opportunity in the history of ecological science. The Global Ecosystem Research Infrastructure (GERI) is an integrated network of analogous, but independent, site-based ecosystem research infrastructures (ERI) dedicated to better understand the function and change of indicator ecosystems across global biomes. Bringing together these ERIs, harmonizing their respective data and reducing uncertainties enables broader cross-continental ecological research. It will also enhance the research community capabilities to address current and anticipate future global scale ecological challenges. Moreover, increasing the international capabilities of these ERIs goes beyond their original design intent, and is an unexpected added value of these large national investments. Here, we identify specific global grand challenge areas and research trends to advance the ecological frontiers across continents that can be addressed through the federation of these cross-continental-scale ERIs.
    Description: This manuscript is in part the product of several workshops and ongoing GERI development. The first workshop was the Terrestrial Ecosystem Research Network (TERN) sponsored and entitled: “Towards a Global Ecosystem Observatory”, 5–7 March 2017, University of Queensland, Brisbane Australia. Another workshop was sponsored by Chinese Academy of Sciences (CAS) and entitled: “Global Integrated Research Infrastructure component in Next Generation ILTER”, 17–20 April, 2018, South China Botanical Garden, Zhaoqing, Guangdong Province, China. The National Science Foundation (NSF) supported two workshops. The first was entitled: ‘Building a Global Ecological Understanding’ held at the University of Delaware, Newark Delaware, 3–6 June, 2016 (NSF 1347883) and the second entitled: “Global Environmental Research Infrastructure (GERI) Planning Workshop”, held at NEON HQ, Boulder Colorado, 25–27 June 2019 (NSF 1917180). The authors wish to thank the workshop attendees for their thoughtful contributions. NEON is a project sponsored by the NSF and managed under cooperative support agreement (DBI-1029808) to Battelle.
    Keywords: Environmental research infrastructure ; Macrosystem science ; Interoperability ; Societal benefit ; New capabilities ; Federating infrastructure
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  • 86
    Publication Date: 2022-10-27
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Hegermiller, C. A., Warner, J. C., Olabarrieta, M., Sherwood, C. R., & Kalra, T. S. Modeling of barrier breaching during hurricanes Sandy and Matthew. Journal of Geophysical Research: Earth Surface, 127(3), (2022): e2021JF006307, https://doi.org/10.1029/2021JF006307.
    Description: Physical processes driving barrier island change during storms are important to understand to mitigate coastal hazards and to evaluate conceptual models for barrier evolution. Spatial variations in barrier island topography, landcover characteristics, and nearshore and back-barrier hydrodynamics can yield complex morphological change that requires models of increasing resolution and physical complexity to predict. Using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system, we investigated two barrier island breaches that occurred on Fire Island, NY during Hurricane Sandy (2012) and at Matanzas, FL during Hurricane Matthew (2016). The model employed a recently implemented infragravity (IG) wave driver to represent the important effects of IG waves on nearshore water levels and sediment transport. The model simulated breaching and other changes with good skill at both locations, resolving differences in the processes and evolution. The breach simulated at Fire Island was 250 m west of the observed breach, whereas the breach simulated at Matanzas was within 100 m of the observed breach. Implementation of the vegetation module of COAWST to allow three-dimensional drag over dune vegetation at Fire Island improved model skill by decreasing flows across the back-barrier, as opposed to varying bottom roughness that did not positively alter model response. Analysis of breach processes at Matanzas indicated that both far-field and local hydrodynamics influenced breach creation and evolution, including remotely generated waves and surge, but also surge propagation through back-barrier waterways. This work underscores the importance of resolving the complexity of nearshore and back-barrier systems when predicting barrier island change during extreme events.
    Description: C. A. Hegermiller is grateful to the U.S. Geological Survey (USGS) Mendenhall Research Fellowship Program for support. This project was supported by the USGS Coastal and Marine Geology Program and the Office of Naval Research, Increasing the Fidelity of Morphological Storm Impact Predictions Project. M. Olabarrieta acknowledges support from the NSF project OCE-1554892.
    Description: 2022-07-26
    Keywords: Breach ; Barrier island ; Hurricane
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  • 87
    Publication Date: 2022-10-27
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zeigler, S. L., Gutierrez, B. T., Lentz, E. E., Plant, N. G., Sturdivant, E. J., & Doran, K. S. Predicted sea-level rise-driven biogeomorphological changes on Fire Island, New York: implications for people and plovers. Earth’s Future, 10(4), (2022): e2021EF002436, https://doi.org/10.1029/2021EF002436.
    Description: Forecasting biogeomorphological conditions for barrier islands is critical for informing sea-level rise (SLR) planning, including management of coastal development and ecosystems. We combined five probabilistic models to predict SLR-driven changes and their implications on Fire Island, New York, by 2050. We predicted barrier island biogeomorphological conditions, dynamic landcover response, piping plover (Charadrius melodus) habitat availability, and probability of storm overwash under three scenarios of shoreline change (SLC) and compared results to observed 2014/2015 conditions. Scenarios assumed increasing rates of mean SLC from 0 to 4.71 m erosion per year. We observed uncertainty in several morphological predictions (e.g., beach width, dune height), suggesting decreasing confidence that Fire Island will evolve in response to SLR as it has in the past. Where most likely conditions could be determined, models predicted that Fire Island would become flatter, narrower, and more overwash-prone with increasing rates of SLC. Beach ecosystems were predicted to respond dynamically to SLR and migrate with the shoreline, while marshes lost the most area of any landcover type compared to 2014/2015 conditions. Such morphological changes may lead to increased flooding or breaching with coastal storms. However—although modest declines in piping plover habitat were observed with SLC—the dynamic response of beaches, flatter topography, and increased likelihood of overwash suggest storms could promote suitable conditions for nesting piping plovers above what our geomorphology models predict. Therefore, Fire Island may offer a conservation opportunity for coastal species that rely on early successional beach environments if natural overwash processes are encouraged.
    Description: Funding for this work was provided by the U.S. Geological Survey's Coastal and Marine Hazards and Resources Program, with supplemental funding through the Disaster Relief Act.
    Keywords: Sea level rise ; Erosion ; Coastal habitats ; Barrier island ; Shorebirds
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  • 88
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chandanpurkar, H. A., Lee, T., Wang, X., Zhang, H., Fournier, S., Fenty, I., Fukumori, I., Menemenlis, D., Piecuch, C. G., Reager, J. T., Wang, O., & Worden, J. Influence of nonseasonal river discharge on sea surface salinity and height. Journal of Advances in Modeling Earth Systems, 14(2), (2022): e2021MS002715, https://doi.org/10.1029/2021MS002715.
    Description: River discharge influences ocean dynamics and biogeochemistry. Due to the lack of a systematic, up-to-date global measurement network for river discharge, global ocean models typically use seasonal discharge climatology as forcing. This compromises the simulated nonseasonal variation (the deviation from seasonal climatology) of the ocean near river plumes and undermines their usefulness for interdisciplinary research. Recently, a reanalysis-based daily varying global discharge data set was developed, providing the first opportunity to quantify nonseasonal discharge effects on global ocean models. Here we use this data set to force a global ocean model for the 1992–2017 period. We contrast this experiment with another experiment (with identical atmospheric forcings) forced by seasonal climatology from the same discharge data set to isolate nonseasonal discharge effects, focusing on sea surface salinity (SSS) and sea surface height (SSH). Near major river mouths, nonseasonal discharge causes standard deviations in SSS (SSH) of 1.3–3 practical salinity unit (1–2.7 cm). The inclusion of nonseasonal discharge results in notable improvement of model SSS against satellite SSS near most of the tropical-to-midlatitude river mouths and minor improvement of model SSH against satellite or in-situ SSH near some of the river mouths. SSH changes associated with nonseasonal discharge can be explained by salinity effects on halosteric height and estimated accurately through the associated SSS changes. A recent theory predicting river discharge impact on SSH is found to perform reasonably well overall but underestimates the impact on SSH around the global ocean and has limited skill when applied to rivers near the equator and in the Arctic Ocean.
    Description: This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004) with support from the Physical Oceanography (PO) and Modeling, Analysis, and Prediction (MAP) Programs. High-end computing resources for the numerical simulation were provided by the NASA Advanced Supercomputing Division at the Ames Research Center.
    Keywords: River discharge ; Sea surface salinity ; Sea surface height
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  • 89
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in German, C., Baumberger, T., Lilley, M., Lupton, J., Noble, A., Saito, M., Thurber, A., & Blackman, D. Hydrothermal exploration of the southern Chile Rise: sediment‐hosted venting at the Chile Triple Junction. Geochemistry Geophysics Geosystems, 23(3), (2022): e2021GC010317, https://doi.org/10.1029/2021gc010317.
    Description: We report results from a hydrothermal plume survey along the southernmost Chile Rise from the Guamblin Fracture Zone to the Chile Triple Junction (CTJ) encompassing two segments (93 km cumulative length) of intermediate spreading-rate mid-ocean ridge axis. Our approach used in situ water column sensing (CTD, optical clarity, redox disequilibrium) coupled with sampling for shipboard and shore based geochemical analyses (δ3He, CH4, total dissolvable iron (TDFe) and manganese, (TDMn)) to explore for evidence of seafloor hydrothermal venting. Across the entire survey, the only location at which evidence for submarine venting was detected was at the southernmost limit to the survey. There, the source of a dispersing hydrothermal plume was located at 46°16.5’S, 75°47.9’W, coincident with the CTJ itself. The plume exhibits anomalies in both δ3He and dissolved CH4 but no enrichments in TDFe or TDMn beyond what can be attributed to resuspension of sediments covering the seafloor where the ridge intersects the Chile margin. These results are indicative of sediment-hosted venting at the CTJ.
    Description: We acknowledge University of California Ship Funds for their support of that shiptime and the NOAA Ocean Exploration and Research Grant NA08OAR4600757 which supported the research presented here. Finally, we thank two anonymous reviewers whose important contributions helped to improve the final version of this paper. This is PMEL contribution number 5341.
    Keywords: Hydrothermal ; Geochemistry ; Chile Rise ; Chile Triple Junction ; Sediment hosted
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  • 90
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 127(1), (2022): e2021JC017927, https://doi.org/10.1029/2021JC017927.
    Description: Observations and high-resolution numerical modeling are used to investigate the dynamical processes related to the initiation of an advective Marine Heatwave in the Middle Atlantic Bight of the Northwest Atlantic continental shelf. Both the observations and the model identify two significant cross-shelf intrusions in November 2016 and January 2017, with the latter inducing large-magnitude water mass anomalies across the shelf. Model prognostic fields reveal the importance of the combination of cyclonic eddies or ringlets and upwelling-favorable winds in producing the large-distance cross-shelf penetration and temperature/salinity anomalies. The cyclonic eddies in close proximity to the shelfbreak set up local along-isobath pressure gradients and provide favorable conditions for the intensification of the shelfbreak front, both processes driving cross-isobath intrusions of warm, salty offshore water onto the outer continental shelf. Subsequently, strong and persistent upwelling-favorable winds drive a rapid, bottom intensified cross-shelf penetration in January 2017 composed of the anomalous water mass off the shelfbreak. The along-shelf settings including realistic representation of bathymetric features are essential in the characteristics of the cross-shelf penetration. The results highlight the importance of smaller scale cyclonic eddies and the intricacy of the interplay between multiple processes to drive significant cross-shelf events.
    Description: This work was supported by Woods Hole Oceanographic Institution (WHOI) Independent Research and Development (IR&D) award and National Oceanic and Atmospheric Administration (NOAA) Climate Program Office (CPO) Climate Variability and Predictability (CVP) program under grant NA20OAR4310398. Numerical modeling work was conducted at WHOI High-Performance Computing cluster Poseidon with startup support to Ke Chen.
    Description: 2022-06-08
    Keywords: Drivers of Marine heatwave ; Warm core rings and cyclonic eddies ; Shelfbreak front and frontogenesis ; Pressure gradient setup ; Wind-driven upwelling and bottom intrusion ; Cross-shelf exchange
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  • 91
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49, (2022): e2021GL096530, https://doi.org/10.1029/2021gl096530.
    Description: Water-mass transports in the vast and seemingly quiescent abyssal ocean, basically along topographically-guided pathways, play a pivotal role in the Earth's climate. The pulse of abyssal circulations can be taken with observations at topographic choke points. The Yap-Mariana Junction (YMJ) is the exclusive choke point through which the Lower Circumpolar Deep Water (LCDW) enters the Philippine Sea. Here, we quantify the LCDW transport and its variability based on mooring observations at the YMJ and the Mariana Trench (MT). The LCDW flows northward toward the Philippine Sea as an intensified current on the western side of the YMJ, with maximum mean velocity reaching 7.6 cm/s. The mean LCDW transports through the MT and the YMJ are 2.2 ± 1.0 Sv and 2.1 ± 0.4 Sv, respectively. Reversal flow at autumn in both the YMJ and MT is captured, indicating seasonal variability of the abyssal flow.
    Description: This work was supported by the National Natural Science Foundation of China (Grant no. 91858203, 91958205, 42076027, 41676011), the National Key R&D Program of China (Grant no. 2018YFC0309800), the Global Change and Air–Sea Interaction Project (Grant no. GASI-IPOVAI-01-03, GASI-IPOVAI-01-02).
    Description: 2022-07-28
    Keywords: Abyssal circulation ; Yap-Mariana Junction ; Lower circumpolar deep water
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  • 92
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wu, J., Parnell‐Turner, R., Fornari, D., Kurras, G., Berrios‐Rivera, N., Barreyre, T., & McDermott, J. Extent and volume of lava flows erupted at 9°50’N, East Pacific Rise in 2005–2006 from autonomous underwater vehicle surveys. Geochemistry Geophysics Geosystems, 23, (2022): e2021GC010213, https://doi.org/10.1029/2021gc010213.
    Description: Seafloor volcanic eruptions are difficult to directly observe due to lengthy eruption cycles and the remote location of mid-ocean ridges. Volcanic eruptions in 2005–2006 at 9°50′N on the East Pacific Rise have been well documented, but the lava volume and flow extent remain uncertain because of the limited near-bottom bathymetric data. We present near-bottom data collected during 19 autonomous underwater vehicle (AUV) Sentry dives at 9°50′N in 2018, 2019, and 2021. The resulting 1 m-resolution bathymetric grid and 20 cm-resolution sidescan sonar images cover 115 km2, and span the entire area of the 2005–2006 eruptions, including an 8 km2 pre-eruption survey collected with AUV ABE in 2001. Pre- and post-eruption surveys, combined with sidescan sonar images and seismo-acoustic impulsive events recorded during the eruptions, are used to quantify the lava flow extent and to estimate changes in seafloor depth caused by lava emplacement. During the 2005–2006 eruptions, lava flowed up to ∼3 km away from the axial summit trough, covering an area of ∼20.8 km2; ∼50% larger than previously thought. Where pre- and post-eruption surveys overlap, individual flow lobes can be resolved, confirming that lava thickness varies from ∼1 to 10 m, and increases with distance from eruptive fissures. The resulting lava volume estimate indicates that ∼57% of the melt extracted from the axial melt lens probably remained in the subsurface as dikes. These observations provide insights into recharge cycles in the subsurface magma system, and are a baseline for studying future eruptions at the 9°50′N area.
    Description: This project is supported by National Science Foundation grants OCE-1834797, OCE-1949485, OCE-194893, OCE-1949938, and by Scripps Institution of Oceanography's David DeLaCour Endowment Fund.
    Keywords: Submarine volcanism ; Mid-ocean ridges ; Autonomous underwater vehicle ; Eruption cycles ; Seafloor mapping
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  • 93
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(12), (2021): e2021JB022201, https://doi.org/10.1029/2021JB022201.
    Description: Sparse wide-angle seismic profiling supported by coincident reflection imaging has been instrumental for advancing our knowledge about rifted margins. Nevertheless, features of critical importance for understanding rifting processes have been poorly resolved. We derive a high-resolution velocity model by applying full waveform inversion to the dense OETR-2009 wide-angle seismic profile crossing the northeastern Nova Scotian margin. We then create a coincident reflection image by prestack depth migrating the multichannel seismic data. This allows for the first detailed interpretation of the structures related to the final stages of continental breakup and incipient oceanic accretion at the Eastern North America Margin. Our interpretation includes a hyperextended continental domain overlying partially serpentinized mantle, followed by a 10-km-wide domain consisting of a continental block surrounded by layered and bright reflectors indicative of magmatic extrusions. A major fault, representing the continent-ocean boundary, marks a sharp seaward transition to a 16-km-wide domain characterized by smoother basement with chaotic reflectors, where no continental materials are present and a 3-km-thick embryonic oceanic crust overlying partially serpentinized mantle is created by the breakup magmatism. Further seaward, thin oceanic crust overlies the serpentinized mantle suggesting magma-poor oceanic spreading with variable magma supply as determined from variable basement topography, 2–4 km thick volcanic layer, and magnetic anomalies. Our results demonstrate that magmatism played an important role in the lithospheric breakup of the area crossed by the OETR-2009 profile. Considering that the northeastern Nova Scotian margin has been classified as amagmatic, large margin-parallel variations in magma supply likely characterize a single rift segment.
    Description: H. Jian was supported by the Ocean Frontier Institute International Postdoctoral Fellowship at Dalhousie University and NSF grant OCE-2001012.
    Keywords: Rifted continental margin ; Magma-poor rifting ; Breakup magmatism ; Nova Scotian margin
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  • 94
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Jonell, T., Giosan, L., Clift, P., Carter, A., Bretschneider, L., Hathorne, E., Barbarano, M., Garzanti, E., Vezzoli, G., & Naing, T. No modern Irrawaddy River until the late Miocene-Pliocene. Earth and Planetary Science Letters, 584, (2022): 117516, https://doi.org/10.1016/j.epsl.2022.117516.
    Description: The deposits of large Asian rivers with unique drainage geometries have attracted considerable attention due to their explanatory power concerning tectonism, surface uplift and upstream drainage evolution. This study presents the first petrographic, heavy mineral, Nd and Sr isotope geochemistry, and detrital zircon geochronology results from the Holocene Irrawaddy megadelta alongside modern and ancient sedimentary provenance datasets to assess the late Neogene evolution of the Irrawaddy River. Contrary to models advocating a steady post-middle Miocene river, we reveal an evolution of the Irrawaddy River more compatible with regional evidence for kinematic reorganization in Myanmar during late-stage India-Asia collision. Quaternary sediments are remarkably consistent in terms of provenance but highlight significant decoupling amongst fine and coarse fraction 87Sr/86Sr and due to hydraulic sorting. Only well after the late Miocene do petrographic, heavy mineral, isotope geochemistry, and detrital zircon U–Pb results from the trunk Irrawaddy and its tributaries achieve modern-day signatures. The primary driver giving rise to the geometry and provenance signature of the modern Irrawaddy River was regional late Miocene (≤10 Ma) basin inversion coupled with uplift and cumulative displacement along the Sagaing Fault. Middle to late Miocene provenance signatures cannot be reconciled with modern river geometries, and thus require significant loss of headwaters feeding the Chindwin subbasin after ∼14 Ma and the northern Shwebo subbasin after ∼11 Ma. Large-scale reworking after ∼7 Ma is evidenced by modern Irrawaddy River provenance, by entrenchment of the nascent drainage through Plio-Pleistocene inversion structures, and in the transfer of significant sediment volumes to the Andaman Sea.
    Description: TNJ was supported in initial stages of this project by a Postdoctoral Research Fellowship at UQ and software support by LSU. LG thanks support from the Andrew W. Mellon Foundation via Woods Hole Oceanographic Institution. The Charles T. McCord chair at LSU funded coring and detrital zircon U–Pb geochronology essential to the study.
    Keywords: Provenance ; Sediment ; Irrawaddy ; Zircon ; Isotope geochemistry ; Petrography
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  • 95
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rovira‐Navarro, M., Katz, R., Liao, Y., Wal, W., & Nimmo, F. The tides of Enceladus’ porous core. Journal of Geophysical Research: Planets, 127, (2022): e2021JE007117, https://doi.org/10.1029/2021je007117.
    Description: The inferred density of Enceladus' core, together with evidence of hydrothermal activity within the moon, suggests that the core is porous. Tidal dissipation in an unconsolidated core has been proposed as the main source of Enceladus' geological activity. However, the tidal response of its core has generally been modeled assuming it behaves viscoelastically rather than poroviscoelastically. In this work, we analyze the poroviscoelastic response to better constrain the distribution of tidal dissipation within Enceladus. A poroviscoelastic body has a different tidal response than a viscoelastic one; pressure within the pores alters the stress field and induces a Darcian porous flow. This flow represents an additional pathway for energy dissipation. Using Biot's theory of poroviscoelasticity, we develop a new framework to obtain the tidal response of a spherically symmetric, self-gravitating moon with porous layers and apply it to Enceladus. We show that the boundary conditions at the interface of the core and overlying ocean play a key role in the tidal response. The ocean hinders the development of a large-amplitude Darcian flow, making negligible the Darcian contribution to the dissipation budget. We therefore infer that Enceladus' core can be the source of its geological activity only if it has a low rigidity and a very low viscosity. A future mission to Enceladus could test this hypothesis by measuring the phase lags of tidally induced changes of gravitational potential and surface displacements.
    Description: M. Rovira-Navarro has been financially supported by the Space Research User Support program of the Netherlands Organization for Scientific Research (NWO) under contract number ALW-GO/16–19. F. Nimmo and Y. Liao have been supported by the National Aeronautics and Space Administration (NASA) Solar System Workings (SSW) Program, Grant No. 80NSSC21K0158. R. Katz acknowledges funding from the Leverhulme Trust through a Research Project Grant.
    Keywords: Enceladus ; Tides ; Poroviscoelasticity ; Interior ; Hydrotherma
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  • 96
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 127(5), (2022): e2021JC018359, https://doi.org/10.1029/2021JC018359.
    Description: Climate change is transforming the Arctic Ocean in unprecedented ways which can be most directly observed in the systematic decline in seasonal ice coverage. From the collection and analysis of particulate and dissolved activities of 210Po and 210Pb from four deepwater superstations, as a part of the US Arctic GEOTRACES cruise during 2015, and in conjunction with previously published data, the temporal and spatial variations in their activities, inventories and residence times are evaluated. The results show that the partitioning of particulate and dissolved phases has changed significantly in the 8 years between 2007 and 2015, while the total 210Po and 210Pb activities have remained relatively unchanged. Observed total 210Po/210Pb activity ratio was less than unity in all deepwater stations, implying disequilibria in the entire water column. From the distribution of total 210Po and 210Pb in the upper 500 m of all major Arctic Basins, the derived scavenging efficiencies decrease as per the following sequence: Makarov Basin 〉 Gakkel Bridge 〉 Canada Basin Nansen Basin ∼ Amundsen Basin 〉 Alpha Ridge, which is the reverse order of the calculated residence times of 210PoT. The scavenging intensities differ between the fully ice-covered, partially ice-covered, and no ice-covered stations, as observed from the differences in the average activities of 210Po and 210Pb. The average settling velocity of particulate matter based on the 210Pb activity is similar to the published values based on 230Th, indicating removal mechanism(s) of Th and Pb is (are) similar.
    Description: This work was supported by National Science Foundation grants (NSF-PLR-1434578, MB; and NSF-OPP-1435376 KM). Mark Baskaran (PI) and Kanchan Maiti were independently funded by NSF.
    Description: 2022-10-06
    Keywords: 210Po ; 210Pb ; Biogeochemical cycles in the Arctic ; Residence time ; Climate change impacts in the Arctic Ocean
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  • 97
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 36(6), (2022): e2022GB007330, https://doi.org/10.1029/2022gb007330.
    Description: Processes controlling dissolved barium (dBa) were investigated along the GEOTRACES GA03 North Atlantic and GP16 Eastern Tropical Pacific transects, which traversed similar physical and biogeochemical provinces. Dissolved Ba concentrations are lowest in surface waters (∼35–50 nmol kg−1) and increase to 70–80 and 140–150 nmol kg−1 in deep waters of the Atlantic and Pacific transects, respectively. Using water mass mixing models, we estimate conservative mixing that accounts for most of dBa variability in both transects. To examine nonconservative processes, particulate excess Ba (pBaxs) formation and dissolution rates were tracked by normalizing particulate excess 230Th activities. Th-normalized pBaxs fluxes, with barite as the likely phase, have subsurface maxima in the top 1,000 m (∼100–200 μmol m−2 year−1 average) in both basins. Barite precipitation depletes dBa within oxygen minimum zones from concentrations predicted by water mass mixing, whereas inputs from continental margins, particle dissolution in the water column, and benthic diffusive flux raise dBa above predications. Average pBaxs burial efficiencies along GA03 and GP16 are ∼37% and 17%–100%, respectively, and do not seem to be predicated on barite saturation indices in the overlying water column. Using published values, we reevaluate the global freshwater dBa river input as 6.6 ± 3.9 Gmol year−1. Estuarine mixing processes may add another 3–13 Gmol year−1. Dissolved Ba inputs from broad shallow continental margins, previously unaccounted for in global marine summaries, are substantial (∼17 Gmol year−1), exceeding terrestrial freshwater inputs. Revising river and shelf dBa inputs may help bring the marine Ba isotope budget more into balance.
    Description: The International GEOTRACES Programme is possible in part thanks to the support from the U.S. National Science Foundation (Grant OCE-1840868) to the Scientific Committee on Oceanic Research (SCOR). This research was supported by the National Science Foundation under Grant No. NSF OCE-0927951, NSF OCE-1137851, NSF OCE-1261214, and NSF OCE-1925503 to A. M. Shiller; NSF OCE-1829563 to R. F. Anderson; NSF OCE-0927064 and NSF OCE-1233688 to R. F. Anderson and M. Q. Fleisher; NSF OCE-0927754 to R. Lawrence Edwards; NSF OCE-1233903 to R. Lawrence Edwards and H. Cheng; NSF OCE-0926860 to L. F. Robinson; NSF OCE-0963026 and NSF OCE-1518110 to P. J. Lam; and NSF OCE-1232814 to B. S. Twining.
    Keywords: Barium ; Excess barium ; Barite ; GEOTRACES ; Th-normalized flux ; Burial efficiency
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  • 98
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Reyes-Macaya, D., Hoogakker, B., Martinez-Mendez, G., Llanillo, P. J., Grasse, P., Mohtadi, M., Mix, A., Leng, M. J., Struck, U., McCorkle, D. C., Troncoso, M., Gayo, E. M., Lange, C. B., Farias, L., Carhuapoma, W., Graco, M., Cornejo-D’Ottone, M., De Pol Holz, R., Fernandez, C., Narvaez, D., Vargas, C. A., García-Araya, F., Hebbeln, D. Isotopic characterization of water masses in the Southeast Pacific Region: paleoceanographic implications. Journal of Geophysical Research: Oceans, 127(1), (2022): e2021JC017525, https://doi.org/10.1029/2021JC017525.
    Description: In this study, we used stable isotopes of oxygen (δ18O), deuterium (δD), and dissolved inorganic carbon (δ13CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71°–78°W) and an oceanic (82°–98°W) water masses (SAAW—Subantarctic Surface Water; STW—Subtropical Water; ESSW—Equatorial Subsurface water; AAIW—Antarctic Intermediate Water; PDW—Pacific Deep Water) of the Southeast Pacific (SEP). The results show that δ18O and δD can be used to differentiate between SAAW-STW, SAAW-ESSW, and ESSW-AAIW. δ13CDIC signatures can be used to differentiate between STW-ESSW (oceanic section), SAAW-ESSW, ESSW-AAIW, and AAIW-PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1,000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present-day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples.
    Description: R/V Sonne cruises (SO102, SO211 ad SO245) were financed by the German Federal Ministry of Education and Research projects #03G0102A, #03G0211A and #03G0245A. SO261 cruise was funded by the HADES-ERC Advanced Grant (“Benthic diagenesis and microbiology of hadal trenches” Grant agreement No. 669947) awarded to R. N. Glud (SDU, Denmark). SO245 cruise recived contributions from the Max Planck Society (Germany), the German State of Lower Saxony, the National Environmental Research Council of Great Britain and the Science Foundation of Ireland. R/V Meteor cruise M93 was financed by the Sonderforschungsbereich 754 “Climate-Biogeochemistry Interactions in the Tropical Ocean” (www.sfb754.de), which is supported by the Deutsche Forschungsgemeinschaft. “Expedición TAITAO” was financed by the grant “Concurso Nacional de Asignación de Tiempo de Buque ASG-61 Cabo de Hornos” AUB180003, FONDECyT grants 11161091 (DN), 1180954 (CF), and the COPAS Sur-Austral Center (CONICYT PIA APOYO CCTE AFB170006). Sampling at Time-Series station 18 off Concepción during 2015 was funded by several FONDECYT/ANID grants from researchers at the Department of Oceanography and Research Line 5 of COPAS Sur-Austral (UdeC). ANID—Chile National Competition for ship time (AUB 150006/12806) financed the expedition LowpHOX organized by the Millennium Institute of Oceanography (IMO). The expedition Crio1218 was financed by the PPR 137 titled “Proyecto de Estudio Integrado del Afloramiento Costero Frente a Perú" and sponsored by IMARPE-Perú. Additional funding was provided by the ANID—Millennium Science Initiative Program—NCN19_153 (Millennium Nucleus UPWELL), ANID/FONDAP (CR)2 15110009 (LF and EMG), FONDECYT Grant 1210171 (CAV), ANID/FONDAP IDEAL 15150003 (CBL), and the Millennium Institute of Oceanography (IMO, ICN12_019). Dharma A. Reyes-Macaya was supported by Becas Chile (17342817-0), DAAD (57144001) and FARGO project (FAte of ocean oxygenation in a waRminG wOrld, UKRI).
    Keywords: Oxygen and deuterium stable isotopes in seawater ; Carbon stable isotopes in dissolved inorganic carbon ; Southeast Pacific ; Water mass distribution ; Paleoceanography proxies
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  • 99
    Publication Date: 2022-10-26
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Liao, F., Liang, X., Li, Y., & Spall, M. Hidden upwelling systems associated with major western boundary currents. Journal of Geophysical Research: Oceans. 127, (2022): e2021JC017649, https://doi.org/10.1029/2021jc017649.
    Description: Western boundary currents (WBCs) play an essential role in regulating global climate. In contrast to their widely examined horizontal motions, less attention has been paid to vertical motions associated with WBCs. Here, we examine vertical motions associated with the major WBCs by analyzing vertical velocity from five ocean synthesis products and one eddy-resolving ocean simulation. These data reveal robust and intense subsurface upwelling systems, which are primarily along isopycnal surfaces, in five major subtropical WBC systems. These upwelling systems are part of basin-scale overturning circulations and are likely driven by meridional pressure gradients along the western boundary. Globally, the WBC upwelling contributes significantly to the vertical transport of water mass and ocean properties and is an essential yet overlooked branch of the global ocean circulation. In addition, the WBC upwelling intersects the oceanic euphotic and mixed layers, and thus likely plays an important role in ocean biological and chemical processes by transporting nutrients, carbon and other tracers vertically inside the ocean. This study calls for more research into the dynamics of the WBC upwelling and their role in the ocean and climate systems.
    Description: X. Liang is supported by the National Science Foundation through Grants OCE-2021274, OCE-2122507, and the Alfred P. Sloan Foundation through Grant FG-2019-12536. M. Spall is supported through the National Science Foundation Grants OCE-1947290 and OCE-2122633.
    Keywords: Western boundary current ; Upwelling ; Overturning circulation ; Ocean vertical transport ; Ocean synthesis products ; Ocean vertical velocity
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  • 100
    Publication Date: 2022-10-19
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 37(1), (2022): e020PA004137, https://doi.org/10.1029/2020PA004137.
    Description: Reconstructions of aeolian dust flux to West African margin sediments can be used to explore changing atmospheric circulation and hydroclimate over North Africa on millennial to orbital timescales. Here, we extend West African margin dust flux records back to 37 ka in a transect of sites from 19° to 27°N, and back to 67 ka at Ocean Drilling Program (ODP) Hole 658C, in order to explore the interplay of orbital and high-latitude forcings on North African climate and make quantitative estimates of dust flux during the core of the Last Glacial Maximum (LGM). The ODP 658C record shows a Green Sahara interval from 60 to 50 ka during a time of high Northern Hemisphere summer insolation, with dust fluxes similar to levels during the early Holocene African Humid Period, and an abrupt peak in flux during Heinrich event 5a (H5a). Dust fluxes increase from 50 to 35 ka while the high-latitude Northern Hemisphere cools, with peaks in dust flux associated with North Atlantic cool events. From 35 ka through the LGM dust deposition decreases in all cores, and little response is observed to low-latitude insolation changes. Dust fluxes at sites from 21° to 27°N were near late Holocene levels during the LGM time slice, suggesting a more muted LGM response than observed from mid-latitude dust sources. Records along the northwest African margin suggest important differences in wind responses during different stadials, with maximum dust flux anomalies centered south of 20°N during H1 and north of 20°N during the Younger Dryas.
    Description: This research was supported by NSF #OCE-1103262 to L. Bradtmiller, NSF #OCE-1030784 to D. McGee, P. deMenocal, and G. Winckler, and by internal grants from Macalester College and MIT.
    Description: 2022-06-07
    Keywords: North Africa ; Dust flux ; Aeolian dust ; Green Sahara ; Stadials
    Repository Name: Woods Hole Open Access Server
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