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  • Articles  (38)
  • 04. Solid Earth
  • 2020-2022  (38)
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  • Articles  (38)
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  • 1
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    The Christmas 2018 Eruption at Mount Etna: Enlightening How the Volcano Factory Works Through a Multiparametric Inspection (2021)
    John Wiley & Sons, Inc
    Details
    Publication Date: 2021-01-07
    Description: The 24–27 December 2018 flank eruption at Mount Etna (Southern Italy) has been investigated through a multidisciplinary approach in which olivine chemical zoning and diffusion chronometry data were integrated with models inferred by GNSS (Global Navigation Satellite System) measurements. Inspection of the olivine chemical zoning from core to rim allowed the identification of some dominant ways of transfer and interaction between magmas pertaining to different magmatic environments. Most of crystal cores are representative of crystallization at pressure of 290–230 and 160–120 MPa. Olivine rims suggest re‐equilibration at shallow pressure (≤30 MPa). Geodetic‐based models indicate pressurization of near‐vertical prolate spheroidal sources centered at ∼7.2 km below sea level (bsl) between 9 June 2017 and 28 June 2018 and later at ∼5.1 km bsl between 28 June 2018 and the eruption onset. Geodetic data also highlight a change in the inflation rate since late June 2018 and later around November 2018, which has been here related to both replenishment phases and magma uprising across the plumbing system. Timescales of magma replenishment are in agreement with prolonged recharge from deep levels upward to shallow environments started about 6 months before the eruption, with further replenishment involving the upper magmatic environments just 3–16 days before the eruption. At present, the eruptive activity at the volcano is primarily controlled by pressure imbalances affecting extensive sections of the plumbing system, with possibility to develop persistent eruptive activity at the summit versus flank eruptions depending on fortuitous interruptions of the steady magma recharge/discharge rate at shallow levels.
    Description: Università di Catania (University of Catania). Grant Numbers: Three Year Plan 2016‐18 project code 22722132140, Three Year Plan 2020‐22 project code 22722132140
    Description: Published
    Description: e2020GC009226
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: plumbing system ; volcano geodesy ; inflation ; eruption ; 04. Solid Earth ; 04.03. Geodesy ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
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    Geodetic Study of the 2006–2010 Ground Deformation in La Palma (Canary Islands): Observational Results (2021)
    MDPI
    Details
    Publication Date: 2021-01-07
    Description: La Palma is one of the youngest of the Canary Islands, and historically the most active. The recent activity and unrest in the archipelago, the moderate seismicity observed in 2017 and 2018 and the possibility of catastrophic landslides related to the Cumbre Vieja volcano have made it strongly advisable to ensure a realistic knowledge of the background surface deformation on the island. This will then allow any anomalous deformation related to potential volcanic unrest on the island to be detected by monitoring the surface deformation. We describe here the observation results obtained during the 2006–2010 period using geodetic techniques such as Global Navigation Satellite System (GNSS), Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) and microgravimetry. These results show that, although there are no significant associated variations in gravity, there is a clear surface deformation that is spatially and temporally variable. Our results are discussed from the point of view of the unrest and its implications for the definition of an operational geodetic monitoring system for the island
    Description: This research was mainly funded by the Spanish Ministerio de Ciencia, Innovación y Universidades research project DEEP-MAPS, grant agreement number RTI2018-093874-B-I00. It was also partially supported by the CSIC project 201530E019 and the project GEOSIR, grant agreement AYA2010-17448 from the Spanish Ministerio de Ciencia e Innovación.
    Description: Published
    Description: 2566
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: A-DInSAR ; GNSS ; gravimetry ; La Palma ; Canary Islands ; volcanic unrest ; 04. Solid Earth ; 04.03. Geodesy ; 04.02. Exploration geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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    Bollettino Sismico Italiano gennaio – aprile 2020 (2021)
    Details
    Publication Date: 2021-04-16
    Description: Nel periodo che va dal 1 gennaio al 30 aprile 2020, gli analisti del BSI hanno effettuato la revisione di tutti gli eventi di magnitudo M≥1.5, registrati dalle stazioni sismiche dell’INGV. I terremoti di magnitudo inferiore a tale soglia di revisione vengono localizzati in tempo reale, nella sala di sorveglianza sismica di Roma. I terremoti di M≥3.5, e pochi altri di particolare interesse (vedi Marchetti et al., 2016, DOI: 10.4401/ag-7169), vengono revisionati dagli analisti del BSI, contestualmente al loro accadimento.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; gennaio - aprile 2020 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Granger Causality Analysis of Geophysical, Geodetic and Geochemical Observations during Volcanic Unrest: A Case Study in the Campi Flegrei Caldera (Italy) (2021)
    MDPI
    Details
    Publication Date: 2021-05-12
    Description: The recent signs of reawakening at Campi Flegrei caldera (Southern Italy) received a great deal of attention due to the issues related to the volcanic risk management in a densely populated area. This paper explores relations between ground deformations, seismicity and geochemical time series in the time span 2004–2016. The aim is to unravel primary processes of unrest and the related indicators which may change in time. Data structure and interactions among variables were examined applying the clustering analysis, the correlations and the Granger causality test. The hierarchical agglomerative clustering detected two sub-periods which were further investigated. In both sub-period causal links were observed between variables while correlations did not appear and vice versa. Thus, well established formal approaches are required to study causal relations. Granger test results indicate that during 2004–2011 the awakening unrest could be mainly ascribed to hydrothermal system pressure fluctuations, probably induced by deep-rooted fluids injection, and that ground deformation together with CO2/H2O appears the most suitable geo-indicators. The 2011–2016 sub-period is characterized by enhanced dynamical connectivity. Granger test results suggest that the unrest is driven by a more localized and shallower thermohydromechanical engine. CO/CO2, He/CH4 and ground deformation velocity are mutually interacting appearing the most suitable geo-indicators.
    Description: INGV Project PRIN n. 20174 × 3P29 FLUIDS
    Description: Published
    Description: 185
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: Granger test; ground deformation; degassing; seismicity; volcanic unrest ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    3D multi-source model of elastic volcanic ground deformation (2021)
    Elsevier B.V.
    Details
    Publication Date: 2021-01-07
    Description: https://www.sciencedirect.com/science/article/abs/pii/S0012821X20303897
    Description: Published
    Description: 116445
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: 3D model ; multi-source ; elastic medium ; ground deformation ; 04. Solid Earth ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    New Insights into Long-Term Aseismic Deformation and Regional Strain Rates from GNSS Data Inversion: The Case of the Pollino and Castrovillari Faults (2021)
    MDPI
    Details
    Publication Date: 2021-01-07
    Description: We present a novel inverse method for discriminating regional deformation and long-term fault creep by inversion of GNSS velocities observed at the spatial scale of intraplate faults by exploiting the different spatial signatures of these two mechanisms. In doing so our method provides a refined estimate of the upper bound of the strain accumulation process. As case study, we apply this method to a six year GNSS campaign (2003–2008) set up in the southern portion of the Pollino Range over the Castrovillari and Pollino faults. We show that regional deformation alone cannot explain the observed deformation pattern and implies high geodetic strain rate, with a WSW-ENE extension of 86±41×10−9/yr. Allowing for the possibility of fault creep, the modelling of GNSS velocities is consistent with their uncertainties and they are mainly explained by a shallow creep over the Pollino fault, with a normal/strike-slip mechanism up to 5 mm/yr. The regional strain rate decrease by about 70 percent and is characterized by WNW-ESE extension of 24±28×10−9/yr. The large uncertainties affecting our estimate of regional strain rate do not allow infering whether the tectonic regime of the area is extensional or strike-slip, although the latter is slightly more likely
    Description: Published
    Description: 2921
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: regional deformation ; fault creep ; GNSS velocities ; inverse theory ; 04. Solid Earth ; 04.03. Geodesy ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Crustal deformation, active tectonics and seismic potential in the Sicily Channel (Central Mediterranean), along the Nubia-Eurasia plate boundary (2021)
    Nature P.G.
    Details
    Publication Date: 2021-01-07
    Description: Based on multidisciplinary data, including seismological and geodetic observations, as well as seismic reflection profiles and gravity maps, we analysed the pattern of crustal deformation and active tectonics in the Sicily Channel, a key observation point to unravel the complex interaction between two major plates, Nubia and Eurasia, in the Mediterranean Sea. Our data highlight the presence of an active ~ 220-km-long complex lithospheric fault system (here named the Lampedusa-Sciacca Shear Zone), approximately oriented N-S, crossing the study area with left-lateral strike-slip deformations, active volcanism and high heat flow. We suggest that this shear zone represents the most active tectonic domain in the area, while the NW-SE elongated rifting pattern, considered the first order tectonic feature, appears currently inactive and sealed by undeformed recent (Lower Pleistocene?) deposits. Estimates of seismological and geodetic moment-rates, 6.58 × 1015 Nm/year and 7.24 × 1017 Nm/year, respectively, suggests that seismicity accounts only for ~ 0.9% of crustal deformation, while the anomalous thermal state and the low thickness of the crust would significantly inhibit frictional sliding in favour of creeping and aseismic deformation. We therefore conclude that a significant amount of the estimated crustal deformation-rate occurs aseismically, opening new scenarios for seismic risk assessments in the region.
    Description: Published
    Description: 21238
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.02. Exploration geophysics ; 04.03. Geodesy ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Reply to Comment by A. Argnani on “Geometry of the Deep Calabrian Subduction From Wide‐Angle Seismic Data and 3‐D Gravity Modeling” (2021)
    Wiley Agu
    Details
    Publication Date: 2021-01-19
    Description: Reply to Argnani, A. (2020). Comment on“Geometry of the deep Calabriansubduction (Central MediterraneanSea) from wide-angle seismic data and3-D gravity modeling” by Dellong et al.Geochemistry, Geophysics, Geosyste ms,21, e2020GC009077, https://doi.org/10.1029/2020GC009077
    Description: Andrea Argnani in his comment on Dellong et al. (2020, https://doi.org/10.1029/2019gc008586) (Geometry of the deep Calabrian subduction (Central Mediterranean Sea) from wide‐angle seismic data and 3‐D gravity modeling) proposes an alternate interpretation of the wide‐angle seismic velocity models presented by Dellong et al. (2018, https://doi.org/10.1002/2017JB015312) and Dellong et al. (2020) and proposes a correction of the literature citations in these paper. In this reply, we discuss in detail all points raised by Andrea Argnani.
    Description: Published
    Description: e2020GC009223
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    DATASET - GAS GEOCHEMISTRY AT GRANDE COMORE AND MAYOTTE VOLCANIC ISLANDS (COMOROS ARCHIPELAGO), INDIAN OCEAN (2021)
    Details
    Publication Date: 2021-07-19
    Description: The Comoros archipelago is an active geodynamic region of intra-plate volcanism within which the youngest and oldest islands (Grande Comore and Mayotte respectively) are characterized by recent volcanic activity. The frequent eruptions of the large shield volcano Karthala on Grande Comore (last eruption 2007), and the recent birth of a large submarine volcano since 2018 at the submarine base of Mayotte are associated with permanent fumarolic emissions, bubbling gas seeps, and soil gas emissions, which are studied in detail here for the first time. CO2 fluxes and chemical and isotopic gas compositions acquired during two surveys in 2017 and 2020 are integrated with older datasets collected between 2005 and 2016, permitting the identification of a possible influence of the recent volcanic and magmatic activity at Mayotte. At Karthala, high gas fluxes with high temperature, and a marked magmatic signature are concentrated close to the summit crater area, while only weaker emissions with a stronger biogenic signature are found on the volcano flanks. At Mayotte, lower temperature and higher CH4 content are recorded in two main seep areas of CO2-rich fluid bubbling, while soil emissions on land record a higher proportion of magmatic fluids compared to Karthala. Our preliminary results reveal two quite separate gas emission patterns for each island that are distinct in composition and isotopic signatures, and well-correlated with the present state of volcanic activity. This work may potentially provide support for local observation infrastructures and contribute to the improvement in volcanic and environmental monitoring.
    Description: INGV (GECO project Fondi Ricerca libera 2019 INGV) and REVOSIMA Initiative (IPGP, CNRS, BRGM, IFREMER)
    Description: Submitted
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Keywords: •Geochemical characterisation of fumarolic and hydrothermal gases in terms of both primary component species and isotopic characteristics ; 04.08. Volcanology ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Can Hydrocarbon Extraction From the Crust Enhance or Inhibit Seismicity in Tectonically Active Regions? A Statistical Study in Italy (2021)
    Frontiers
    Details
    Publication Date: 2021-07-07
    Description: A number of oil- and gas-producing leases have been operating in Italy in the last decades, many of which are located in the surroundings of tectonically active regions. Identifying human-induced seismicity in areas with high levels of natural seismicity is a difficult task for which virtually any result can be a source of controversy. We implemented a large-scale analysis aiming at tracking significant departures of background seismicity from a stationary behavior around active oil and gas development leases in Italy. We analyzed seismicity rates before and after hydrocarbon peak production in six oil-producing and 43 gas-producing leases, and evaluate the significance of possible seismicity rate changes. In a considerable number of cases seismicity rate results stationary. None of the observed cases of seismicity rate increase after the peak production is statistically significant (at a s.l. = 0.05). Conversely, considering cases of seismicity rate decrease after peak production, our results suggest that the seismicity rate reduction is statistically significant (s.l. = 0.05) around one oil-producing lease (Val d’Agri, Basilicata) and around a cluster of gas-producing leases in Sicily. Our results put in evidence correlated changes between the rates of shallow seismicity and hydrocarbon production in these areas, which are then identified as hotspots requiring more detailed research; assessing actual causal relationships between these processes will require further physically-based modelling. If a physical causative link between these processes exists, then the observed seismicity rate reduction could either be due to increased seismicity during the progressive increase in production before reaching its maximum, or to an actual seismicity rate reduction after that peak. Considering that there is evidence of seismicity occurring before the start of hydrocarbon production, which contrasts with the evident reduction of events observed after the peak production, we think it likely that the seismicity inhibition is a plausible hypothesis. Using a simple model we also calculate Coulomb stress changes in planes optimally oriented for failure, and we show that under some conditions the inhibition of seismicity is feasible in at least one of these cases. We conclude that more efforts to study the mechanisms and the possible consequences of anthropogenically-driven seismicity inhibition are required.
    Description: This study was performed with the support of Clypea, the Innovation Network for Future Energy financed by the Italian Ministry of Economic Development, Direzione Generale per le Infrastrutture e la Sicurezza dei Sistemi Energetici e Geominerari (MISE—DGISSEG)
    Description: Published
    Description: 673124
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: regional seismicity ; hydrocarbon production ; correlation analysis ; seismicity rate changes ; Italy, ; anthropogenic hazards ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Geodetic Deformation versus Seismic Crustal Moment-Rates: Insights from the Ibero-Maghrebian Region (2021)
    MDPI
    Details
    Publication Date: 2021-01-07
    Description: Seismic and geodetic moment-rate comparisons can reveal regions with unexpected potential seismic hazards. We performed such a comparison for the Southeastern Iberia—Maghreb region. Located at the western Mediterranean border along the Eurasia–Nubia plate convergence, the region has been subject to a number of large earthquakes (M ≥ 6.5) in the last millennium. To this end, on the basis of available geological, tectonic, and seismological data, we divided the study area into twenty-five seismogenic source zones. Many of these seismogenic source zones, comprising the Western Betics, the Western Rif mountains, and the High, Middle, and Saharan Atlas, are characterized by seismic/geodetic ratio values lower than 23%, evidencing their prevailing aseismic behavior. Intermediate seismic/geodetic ratio values (between 35% and 60%) have been observed for some zones belonging to the Eastern Betics, the central Rif, and the Middle Atlas, indicating how crustal seismicity accounts only for a moderate fraction of the total deformation-rate budget. High seismic/geodetic ratio values (〉 95%) have been observed along the Tell Atlas, highlighting a fully seismic deformation.
    Description: The research performed in this study was partially supported by the Spanish CGL2015-65602-R, CGL2016-80687-R and RTI2018-093874-B-100 projects, and the Programa Operativo FEDER Andalucía 2014-2020 – call made by the University of Jaén 2018.
    Description: Published
    Description: 952
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: earthquake catalogs ; seismic/aseismic behavior ; GNSS ; earthquake hazards ; Eurasia-Nubia plate ; 04. Solid Earth ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    New Applications in Gas Geochemistry (2021)
    Wiley
    Details
    Publication Date: 2021-02-03
    Description: Gases present in the Earth crust are important in various branches of human activities. Hydrocarbons are a significant energy resource, helium is applied in many high-tech instruments, and studies of crustal gas dynamics provide insight in the geodynamic processes and help monitor seismic and volcanic hazards. Quantitative analysis of methane and CO2 migration is important for climate change studies. Some of them are toxic (H2S, CO2, CO); radon is responsible for the major part of human radiation dose. The development of analytical techniques in gas geochemistry creates opportunities of applying this science in numerous fields. Noble gases, hydrocarbons, CO2, N2, H2, CO, and Hg vapor are measured by advanced methods in various environments and matrices including fluid inclusions. Following the “Geochemical Applications of Noble Gases”(2009), “Frontiers in Gas Geochemistry” (2013), and “Progress in the Application of Gas Geochemistry to Geothermal, Tectonic and Magmatic Studies” (2017) published as special issues of Chemical Geology and “Gas geochemistry: From conventional to unconventional domains” (2018) published as a special issue of Marine and Petroleum Geology, this volume continues the tradition of publishing papers reflecting the diversity in scope and application of gas geochemistry.
    Description: Published
    Description: 976190
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: geochemistry ; Atmosphere ; 03. Hydrosphere ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
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    Geopositioning time series from offshore platforms in the Adriatic Sea (2021)
    Nature P.G.
    Details
    Publication Date: 2021-01-07
    Description: We provide a dataset of 3D coordinate time series of 37 continuous GNSS stations installed for stability monitoring purposes on onshore and offshore industrial settlements along a NW-SE-oriented and ~100-km-wide belt encompassing the eastern Italian coast and the Adriatic Sea. The dataset results from the analysis performed by using different geodetic software (Bernese, GAMIT/GLOBK and GIPSY) and consists of six raw position time series solutions, referred to IGb08 and IGS14 reference frames. Time series analyses and comparisons evidence that the different solutions are consistent between them, despite the use of different software, models, strategy processing and frame realizations. We observe that the offshore stations are subject to significant seasonal oscillations probably due to seasonal environmental loads, seasonal temperature-induced platform deformation and hydrostatic pressure variations. Many stations are characterized by non-linear time series, suggesting a complex interplay between regional (long-term tectonic stress) and local sources of deformation (e.g. reservoirs depletion, sediment compaction). Computed raw time series, logs files, phasor diagrams and time series comparison plots are distributed via PANGAEA ( https://www.pangaea.de ).
    Description: This research was financed by the Italian Economic Development Ministry in the”CLYPEA-Innovation Network for Future Energy” framework, “subsoil deformations” project.
    Description: Published
    Description: 373
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: GNSS ; offshore platforms ; subsidence ; data processing ; oil/gas exploiting ; 04. Solid Earth ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Bollettino Sismico Italiano settembre - dicembre 2020 (2021)
    Details
    Publication Date: 2021-05-18
    Description: La revisione da parte degli analisti del BSI della sismicità registrata in Italia dal 1 settembre al 31 dicembre 2020 ha riguardato tutti i terremoti di magnitudo M≥1.5, mentre i parametri dei terremoti di magnitudo inferiore a tale valore sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma. I terremoti più forti (M≥3.5), e pochi altri di particolare interesse [vedi Marchetti et al., 2016, DOI: 10.4401/ag-6116], sono stati revisionati dagli analisti del BSI, mediamente nelle 24 ore successive al loro accadimento.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; settembre - dicembre 2020 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
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    Syn‐Orogenic Exhumation of High‐P Units by Upward Extrusion in an Accretionary Wedge: Insights From the Eastern Elba Nappe Stack (Northern Apennines, Italy) (2021)
    Wiley Agu
    Details
    Publication Date: 2021-06-15
    Description: The E-vergent Northern Apennines formed by Oligocene-Miocene convergence and westward subduction of Adria beneath Europe. Extension ensued in the Mid-Late Miocene reflecting lower plate roll-back and causing opening of the back-arc Northern Tyrrhenian Sea. Post-orogenic extension is commonly advocated as the main driver of the exhumation of the belt's inner domain highpressure/ low-temperature (HP-LT) rock units. The Acquadolce Subunit of the Eastern Elba nappe stack contains HP-LT rocks recording peak blueschist conditions of 1.5–1.8 GPa at 320°C–370°C loosely dated to the Oligocene-Early Miocene. It is sandwiched by two Late Miocene, out-of-sequence top-to-the E thrusts between Jurassic LP serpentinites on top and HT–LP contact metamorphosed marbles at its base. We document widespread W-verging ductile asymmetries within the Acquadolce Subunit, which correspond to top-to-the W extensional shearing for the nappe stack current orientation. This allowed for early syn-orogenic exhumation from blueschist- to greenschist-facies conditions, wherein coeval W-directed extension at the top of the exhuming units acted synchronously with E-directed thrusting at their base causing exhumation by extrusion in an overall contractional setting. The basal, E-vergent thrusting is, however, challenging to document as the wedge has since been reworked by Late Miocene, E-verging compressive tectonics, contact metamorphism, and later extension, obliterating much of the evidence supporting exhumation by extrusion during the early stages of wedge build-up. Syn-orogenic exhumation by extrusion from deep structural levels within the orogenic wedge is a viable mechanism to account for other exhumed HP-LT units in the inner part of the belt.
    Description: Published
    Description: e2020TC006348
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Syn-orogenic extrusion is proposed as a viable mechanism for the exhumation of HP-LT rock units of the Northern Apennines; • The Acquadolce Subunit of the Eastern Elba nappe stack was exhumed by upward extrusion within an actively shortening orogenic wedge; • Middle Miocene extension shaped the upper Northern Apennines orogenic wedge but did not contribute to the early exhumation of HP rocks. ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
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    Multiscale, radially anisotropic shear wave imaging of the mantle underneath the contiguous United States through joint inversion of USArray and global data sets (2021)
    Oxford University press - RAS
    Details
    Publication Date: 2021-09-21
    Description: EarthScope's USArray seismic component provided unprecedented coverage of the contiguous United States and has therefore spurred significant advances in tomographic imaging and geodynamic modelling. Here, we present a new global, radially anisotropic shear wave velocity tomography model to investigate upper mantle structure and North American Plate dynamics, with a focus on the contiguous United States. The model uses a data-adaptive mesh and traveltimes of both surface waves and body waves to constrain structure in the crust and mantle in order to arrive at a more consistent representation of the subsurface compared to what is provided by existing models. The resulting model is broadly consistent with previous global models at the largest scales, but there are substantial differences under the contiguous United States where we can achieve higher resolution. On these regional scales, the new model contains short wavelength anomalies consistent with regional models derived from USArray data alone. We use the model to explore the geometry of the subducting Farallon Slab, the presence of upper mantle high velocity anomalies, low velocity zones in the central and eastern United States and evaluate models of dynamic topography in the Cordillera. Our models indicate a single, shallowly dipping, discontinuous slab associated with the Farallon Plate, but there are remaining imaging challenges. Inferring dynamic topography from the new model captures both the long-wavelength anomalies common in global models and the short-wavelength anomalies apparent in regional models. Our model thus bridges the gap between high-resolution regional models within the proper uppermost mantle context provided by global models, which is crucial for understanding many of the fundamental questions in continental dynamics.
    Description: Published
    Description: 1730–1746
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    3D Digital Outcrop Model analysis of fracture networks: insights from the Mt. Vettore Fault Zone. (2021)
    Details
    Publication Date: 2021-09-01
    Description: In the last years, several studies investigated the Mt. Vettore Fault Zone (MVFZ), activated during the 2016 Central Italy seismic sequence. Research has focused mainly on aftershocks and mainshock locations, coseismic slip and surface cracks, while an accurate study of the fracture network in the MVFZ was never conducted. In this study we present a fracture analysis performed using very high resolution (0.5 – 5 cm) Digital Outcrop Models (DOMs) that developed by Unmanned Aerial Vehicle (UAV)-based digital photogrammetry. The UAV gave the possibility to investigate outcrops with dimensions up to hundreds of metres high and wide, and acquire big and precise fracture data using 3D digital automatic and manual mapping techniques. To investigate the structural variability of the MVFZ fracture network, we realized several DOMs located in different positions, along and around the major fault. All the selected outcrops are formed by Calcare Massiccio Fm., which better records brittle deformation in the study area. This analysis aimed to better understand the MVFZ fracture network, including mechanics, kinematics and local structural evolution. In particular, it allowed to determine: 1) the main sets of fractures; 2) the geometrical parameters of the fracture network (e.g. fracture density, persistence, roughness and aperture); 3) the relative timing of the main tectonic brittle events. The preliminary analysis of the DOMs suggests a variability of the fracture network parameters over the MVFZ, especially for what concerned fracture set orientation and density.
    Description: Published
    Description: vEGU21: Virtual Conference Online
    Description: 2T. Deformazione crostale attiva
    Keywords: fracture analisys ; very high resolution Digital Outcrop Models ; Unmanned Aerial Vehicle ; digital photogrammetry ; 04. Solid Earth ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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    Insights Into the Origin and Deformation Style of the Continental Moho: A Case-Study From the Western Alps (Italy) (2021)
    Wiley-Agu
    Details
    Publication Date: 2021-09-06
    Description: Several hypotheses on the origin of the continental Moho are still debated and multiple mechanisms may contribute to its formation. Here, we present quantitative estimation of the seismic properties and anisotropy of the crust-mantle transition in the Western Alps where an example of newly formed (proto)-continental Moho is unusually shallow. We make use of teleseismic P-to-S converted-waves recorded by stations deployed on top of the Ivrea Body (IB), a volume of possibly serpentinized mantle peridotite below exhumed (ultra-)high pressure crustal rocks. The IB has been mapped by gravity, magnetic, active and passive seismic surveys suggesting an extremely shallow Moho. We demonstrate that the P-to-S converted waves propagating through this region display coupled features: (a) they record expected presence of strong seismic velocity contrast at shallow depth as due to the lower crustal and upper mantle transition; (b) they are decomposed due to anisotropic properties of rocks involved. The proto-continental Moho is recognized as an increase in S-wave velocity (∼0.4-1 km/s) at shallow depths of 5-10 km. The presence of anisotropy within the IB and overlying crustal rocks is evidenced by back-azimuthal dependence of the amplitude of P-to-S phases. The strength of anisotropy is ∼-14% on average pointing out the presence of metamorphosed/hydrated material (e.g., serpentinite) below the Moho. Anisotropic directions are consistent across Moho in both crust and upper mantle. The similarity of the anisotropy parameters between crust and upper mantle suggests they have been shaped by the same deformation event.
    Description: Published
    Description: e2020JB021319
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Continental Moho; Ivrea body; harmonics decomposition; receiver functions; seismic anisotropy ; 04. Solid Earth
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    Relationship between soil CO2 flux and tectonic structures in SW Sicily (2020)
    Details
    Publication Date: 2020-09-09
    Description: The identification and characterization of seismogenic structures in southwestern Sicily is an open debate both for the geological-structural complexity of this sector and the scarce seismicity as well. In addition, clear morphological evidence of tectonic structures is limited. Besides the geophysical methods, the study of the spatial distribution of soil CO2 flux is a valid methodology to investigate the position and geometry of buried active faults. Indeed, active tectonic structures are channels with high permeability through which deep fluids can migrate toward the atmosphere. Therefore, the alignment of high degassing areas can reveal the presence of preferential ways of rising fluids (i.e. faults). We applied this methodology in SW Sicily in the surrounding of the area hit by the 1968 seismic sequence and in three other areas where evidence of active deformation has been recognized. Furthermore, to investigate the origin of emitted fluids, we measured the carbon isotopic composition of the soil CO2 in some high emission sites. The results showed high spatial variability of soil CO2 fluxes with values ranging from 1 to 430 g m−2d−1. The areal patterns of soil CO2 fluxes in all the areas reveal a strong influence of the main tectonic structures and active deformations on soil CO2 emissions. The range of isotopic data and the distribution of soil CO2 fluxes suggest a supply of deep fluids through the active tectonic structures.
    Description: Published
    Description: SE104
    Description: 2T. Deformazione crostale attiva
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Soil CO2 flux ; Diffusive degassing structures (DDS) ; Active tectonic structures ; Belice Valley ; 04. Solid Earth ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    VINEDA—Volcanic INfrasound Explosions Detector Algorithm (2020)
    Details
    Publication Date: 2021-01-22
    Description: Infrasound is an increasingly popular tool for volcano monitoring, providing insights of the unrest by detecting and characterizing acoustic waves produced by volcanic processes, such as explosions, degassing, rockfalls, and lahars. Efficient event detection from large infrasound databases gathered in volcanic settings relies on the availability of robust and automated workflows. While numerous triggering algorithms for event detection have been proposed in the past, they mostly focus on applications to seismological data. Analyses of acoustic infrasound for signal detection is often performed manually or by application of the traditional short-term average/long-term average (STA/LTA) algorithms, which have shown limitations when applied in volcanic environments, or more generally to signals with poor signal-to-noise ratios. Here, we present a new algorithm specifically designed for automated detection of volcanic explosions from acoustic infrasound data streams. The algorithm is based on the characterization of the shape of the explosion signals, their duration, and frequency content. The algorithm combines noise reduction techniques with automatic feature extraction in order to allow confident detection of signals affected by non-stationary noise. We have benchmarked the performances of the new detector by comparison with both the STA/LTA algorithm and human analysts, with encouraging results. In this manuscript, we present our algorithm and make its software implementation available to other potential users. This algorithm has potential to either be implemented in near real-time monitoring workflows or to catalog pre-existing databases.
    Description: This research was partially funded by KNOWAVES TEC2015- 68752 (MINECO/FEDER), by NERC Grant NE/P00105X/1, by Spanish research grant MECD Jose Castillejo CAS17/00154 and by VOLCANOWAVES European Union’s Horizon 2020 Research and Innovation Programme Under the Marie Sklodowska-Curie Grant Agreement no 798480.
    Description: Published
    Description: Article 335
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: volcanic infrasound explosions ; automatic detection ; signal processing ; characteristic function ; sub-band processing ; 04. Solid Earth ; 04.08. Volcanology
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    Geological Map of the Tocomar Basin (Puna Plateau, NW Argentina). Implication for the Geothermal System Investigation (2020)
    MDPI
    Details
    Publication Date: 2020-10-26
    Description: This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau region.
    Description: Published
    Description: id 5492
    Description: 1TR. Georisorse
    Description: JCR Journal
    Keywords: geothermal exploration ; U/Th dating ; Southern Central Andes ; central Puna ; 04. Solid Earth ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Deep CO2 release revealed by stable isotope and diffuse degassing surveys at Vulcano (Aeolian Islands) in 2015–2018 (2020)
    Elsevier
    Details
    Publication Date: 2020-10-06
    Description: The partitioning of carbon dioxide (CO〈sub〉2〈/sub〉) released by soils at Vulcano Island (Aeolian Islands, Italy) was performed by combining the CO〈sub〉2〈/sub〉 flux and the carbon isotope measurements. Based on this method, the amount of CO〈sub〉2〈/sub〉 of volcanic origin was quantified six times during the period 2015–2018. The data analysis allowed us to establish the correlation between CO〈sub〉2〈/sub〉 soil degassing and changes in the contribution of volcanic fluids. Carbon isotope determinations were performed in situ to enhance the coverage of data collection in space and time. These data were combined with both the CO〈sub〉2〈/sub〉 contents in the ground gases and the soil CO〈sub〉2〈/sub〉 flux. The amount of volcanic CO〈sub〉2〈/sub〉 was distinguished from that of biogenic origin by implementing a three-component mixing model. The results of this study indicate that the increase in CO〈sub〉2〈/sub〉 output in September 2018 reflects the increase in volcanic gas emissions. The measurement method and analysis presented in this work are sufficiently general to be applicable to the monitoring programs of active volcanoes.
    Description: Published
    Description: 106972
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: Carbon dioxide ; CO2 flux ; CO2 isotope composition ; Volcano monitoring ; Volcanic unrest ; Volcanic degassing ; 04. Solid Earth ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Dangerous emissions of endogenous CO2 and H2S from gas blowouts of shallow wells in the Rome Municipality (Italy) (2020)
    Elsevier
    Details
    Publication Date: 2020-11-18
    Description: Highlights -Gas blowouts from water wells are frequent in the southeastern zone of Rome -Emitted gas killed some pets and families had to be evacuated for security reasons -Gas has a magmatic origin with the highest helium R/Ra of Colli Albani gas discharges -Monitoring of soil CO2 flux and air gas concentration allowed to assess gas hazard -Gas diffusing in soil reached nearby houses creating dangerous indoor conditions
    Description: The southeastern zone of Rome city is located at the northwest periphery of the quiescent Colli Albano volcano. This zone is characterized by the presence of a shallow (depth ~ 45–50 m) gas pressurized aquifer that produces gas blowouts when it is reached by wells. Three gas blowouts occurred in this zone in 2003, 2008 (another one was discovered during the present study) and 2016 and in this paper we describe in detail the latter two. The emitted gas consists mostly of CO2 (〉90 vol%) and contains a low but significant quantity of H2S (0.3–0.5 vol%) and it has the highest helium isotopic R/Ra value (1.90) of all Colli Albani natural gas discharges, suggesting its likely magmatic origin. In both the described gas blowouts, dozens of families had to be prudentially evacuated from their houses and the emitted gas killed some animals. We monitored, continuously or by discrete surveys, the soil CO2 flux, the indoor and outdoor air concentration of CO2 and H2S, the environmental parameters and we checked whether the cementation of the gas releasing wells had been effective. In both cases, the upper part of the wells had been partly closed with an inflating packer to avoid free gas dispersion in atmosphere; as a consequence gas diffused laterally from the wells into the permeable surficial soil up to reach the nearest houses creating hazardous indoor conditions, particularly for CO2 in some basements. During the well cementation operations, and in one case because of the packer rupture, gas and nebulized water were freely discharged from the wells into the atmosphere, and high air CO2 and H2S concentrations were found. Fortunately gas was quickly dispersed by strong winds. The positive results obtained in all the studied gas blowouts demonstrate that our applied geochemistry approach represents a model of intervention useful for the assessment of the hazard associated to accidental endogenous gas release. This model is of fundamental importance also to overcome the risk problems created by accidental gas blowout from wells in an urbanized environment, up to the safe return of the people in their evacuated houses.
    Description: Published
    Description: 104769
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: Rome gas blowouts zone ; Hazard assessment of endogenous gas blowouts from wells ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Present-day uplift of the European Alps: Evaluating mechanisms and models of their relative contributions (2020)
    Elsevier
    Details
    Publication Date: 2021-06-25
    Description: Recent measurements of surface vertical displacements of the European Alps show a correlation between vertical velocities and topographic features, with widespread uplift at rates of up to ~2–2.5 mm/a in the North-Western and Central Alps, and ~1 mm/a across a continuous region from the Eastern to the South-Western Alps. Such a rock uplift rate pattern is at odds with the horizontal velocity eld, characterized by shortening and crustal thickening in the Eastern Alps and very limited deformation in the Central and Western Alps. Proposed me- chanisms of rock uplift rate include isostatic response to the last deglaciation, long-term erosion, detachment of the Western Alpine slab, as well as lithospheric and surface de ection due to mantle convection. Here, we assess previous work and present new estimates of the contributions from these mechanisms. Given the large range of model estimates, the isostatic adjustment to deglaciation and erosion are su cient to explain the full observed rate of uplift in the Eastern Alps, which, if correct, would preclude a contribution from horizontal shortening and crustal thickening. Alternatively, uplift is a partitioned response to a range of mechanisms. In the Central and Western Alps, the lithospheric adjustment to deglaciation and erosion likely accounts for roughly half of the rock uplift rate, which points to a noticeable contribution by mantle-related processes such as detachment of the European slab and/or asthenospheric upwelling. While it is di cult to independently constrain the patterns and magnitude of mantle contributions to ongoing Alpine vertical displacements at present, future data should provide additional insights. Regardless, interacting tectonic and surface mass redistribution processes, rather than an individual forcing, best explain ongoing Alpine elevation changes.
    Description: Published
    Description: 589-604
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.03. Geodesy ; 04.07. Tectonophysics
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    Fluid geochemistry in a low-enthalpy geothermal field along a sector of southern Apennines chain (Italy) (2020)
    Elsevier
    Details
    Publication Date: 2020-10-19
    Description: The chemical and isotopic features of the fluids (water and gases) in the Lucane thermal area (southern Italy) have been investigated in order to verify their origin, water temperature in the geothermal reservoir, and to recognize the main natural processes concerning the water composition during ascent towards the surface. The Lucane geothermal system is placed in the southern sector of the Apennines chains, a seismically active area, close to the southern base of the Mt. Alpi carbonate massif. Along the study area, two main sets of high-angle faults form an almost orthogonal fault system that, as suggested by local structural geology, acts as a preferential pathway for uprising deep fluids. Here, we recognized two different types of waters: (i) cold shallow waters having a meteoritic origin and interacting with carbonate rocks (dolomite and calcite), whose dissolved gases show a dominant atmospheric contribution and (ii) hypothermal waters (average temperature of 21 °C), having a meteoritic origin and interacting with both carbonate rocks and inter-bedded evaporitic deposit. Geochemical data allow estimating a geothermal reservoir temperature between 30 °C and 60 °C, according to silica and Ca/ Mg geothermometers, respectively. A heat discharge related to hypothermal groundwater flow between 7.75E +06 and 2.00E+07 J/s was computed. δ18O and δ2Η data allowed recognizing a meteoric origin for hypothermal (hereafter TL) waters, with mean recharge (infiltration) elevations between 1300 and 1700 m a.s.l. These waters are gas-rich (e.g., CO2 and He), which amounts are higher than those in air-saturated water (ASW). Carbon and helium isotope signature in the TL waters indicate their mainly crustal origin and involve a tectonic control on fluid migration through the crust. Furthermore, we observe that the He isotopic signature in gases dissolved in TL waters is stable over time and its monitoring could be a powerful tool to assess the seismogenetic processes since their preparatory phases.
    Description: Published
    Description: 106618
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: geochemistry ; tectonics ; geothermy ; earthquakes ; 04. Solid Earth
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    Hybrid Broadband Seismograms for Seismic Shaking Scenarios: An Application to the Po Plain Sedimentary Basin (Northern Italy) (2020)
    Springer
    Details
    Publication Date: 2021-06-22
    Description: The densely populated Po Plain, a very deep sedi- mentary basin in northern Italy, is prone to heavy shaking during earthquakes. Seismic hazard assessment must account for local variation in wave amplification. Standard ground motion prediction equations may fail to picture the complexity of strong lateral gradients in seismic response, due to sharp structural heterogeneity. For this reason, there is an increasing demand for full waveform predictions for engineering applications. Here, we present an implementation of a hybrid broadband simulation based on the method of Mai et al. (Bull Seismol Soc Am 100(6):3338–3339, 2010), to obtain complete broadband seismograms of 0.1–10 Hz. With this method, low frequency (〈1 Hz) and high frequency (1–10 Hz) seismograms are simulated separately using a deter- ministic and a stochastic method, respectively. We apply the method to four events recorded within the Po basin, with magnitude ranging from Mw = 4.4 to Mw = 5.6. The low frequency (LF) simulation is performed using SPECFEM3D on a few test sub- surface velocity models. The three-dimensional velocity model MAMBo (Molinari et al. in Bull Seismol Soc Am 105(2A):753–764, 2015)—consisting of a detailed structural description of the basin, based on extensive active-source data, embedded within a regional 3D crustal model—provided the best results for broadband simulations that most closely corresponded with the observations. It performed better than an ambient noise tomography model with more accurate S-wave velocities but less well defined layer topographies, emphasizing the importance of first order velocity discontinuities. The high frequency (HF) seis- mograms are simulated using the multiple scattering approach of Zeng et al. (J Geophys Res Solid Earth 96(B1):607–619, 1991). The scattering coefficients are obtained by performing a non linear inversion for each station to find best fitting synthetic envelopes. HF energy is then combined at 1 Hz to match the amplitude and phase spectra of the LF signal. We are able to simulate full waveforms throughout the Po Plain, of which shaking duration matches observed data for stations located in the basin. Shaking amplitudes are generally overestimated in the low frequency simulation by the MAMBo velocity model. Updating the MAMBo velocity model with more accurate S-wave velocity information of the ambient noise tomography model should improve the fit in future simulations.
    Description: Published
    Description: 2181–2198
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Ground motion ; hybrid method ; sedimentary basin ; Seismic shaking scenario ; 04. Solid Earth
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    Space–time evolution of crustal deformation related to the Mw 6.3, 2009 L'Aquila earthquake (central Italy) from principal component analysis inversion of GPS position time-series (2020)
    Details
    Publication Date: 2020-03-03
    Description: This article has been accepted for publication in Geophysical Journal International ©: 2014, Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
    Description: In this work, we present a study of the coseismic and post-seismic crustal deformation associ- ated to the Mw 6.3, 2009 April 6 L’Aquila earthquake from the analysis of GPS displacement time-series. We use a principal component decomposition-based inversion method to study the space- and time-dependent evolution of slip on faults without any a priori assumption on the model used to characterize the temporal evolution of crustal deformation. The method adopted allows us to account for the initial post-seismic deformation in estimating the coseismic dis- placements, in a consistent manner for the whole GPS network. We use elastic dislocation theory and a least-squares procedure to invert for the slip distribution on the mainshock fault (Paganica fault) and a second fault (Campotosto fault), where a Mw 5.2 aftershock occurred on April 9. The geometries for these faults are obtained from a singular value decomposition of precisely relocated aftershocks. We find that the use of complex fault geometries is not justified by the GPS observations available. An inversion that accounts for post-seismic slip to occur on both the Paganica and Campotosto faults provides a better fit to the GPS time-series observations, than using only the Paganica fault segment, at a 95 per cent confidence level. Within our resolution, afterslip regions do not migrate over time and are localized on fault patches that are approximately complementary to those of coseismic slip. We find that the position of some relevant afterslip patches is different if the inversion is performed assuming a fixed rake or not. We estimate the parameter a – b of rate- and state-dependent friction on those fault regions accommodating afterslip that are robustly characterized in our inversions. We find values of the order of 10−3, which is near the transition from potentially unstable to nominally stable friction. These results are in agreement with laboratory measurements performed on typical rocks of the L’Aquila region.
    Description: Published
    Description: 174–191
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: 3T. Sorgente sismica
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.03. Geodesy ; 04.07. Tectonophysics
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    A new methodology for the diagnostics of architectural elements in historical buildings (2020)
    EGU - Copernicus
    Details
    Publication Date: 2020-05-19
    Description: A new methodology is presented consisting of a multi-step procedure based on the integrated application of different diagnostic techniques aimed at recognizing altered and unaltered parts of architectural elements of ancient buildings and at identifying zones where structural damage has occurred on their surface. The methodology was tested on a historical building of the monumental compound in Piazza Palazzo in the historical center of the town of Cagliari (Italy). Three types of carbonate building materials have been used historically to construct ancient monuments in the historical center of Cagliari, which in order of increasing hardness are: Pietra Cantone, Tramezzario and Pietra Forte. Our methodology begins with an accurate microscopic examination of petrographic thin sections and scanning electron microscope (SEM) analysis of the above carbonate materials in order to identify their textural characteristics and especially the nature and distribution of their porosity. Other rock properties such as wet and dry bulk density were calculated from saturated and dry mass and volume respectively. In a second step we used a Leica HDS-6200 terrestrial laser scanner (TLS) to 3D model some building of the studied monumental compound (Piazza Palazzo). Surface geometrical anomalies have been modeled for the most interesting architectural elements, such as a Pietra Cantone portal in Late Gothic style inside the Antico Palazzo di Città, a historical building that hosts the civic museum bearing the same name. Since TLS technology is characterized by high productivity but is unable to investigate the inner parts of the studied materials, a third step of our procedure was complemented by several ultrasonic in situ and laboratory tests in the 54kHz - 82kHz range. The ultrasonic parameters, especially longitudinal and transversal velocities, can be measured very accurately and correlated with various material properties with reasonable confidence. This task has two objectives: one is to compare the petrographical and petrophysical rock properties with the elastic-dynamic ones, while the other is to compare TLS geometrical anomalies with the anomalies of the velocity field detected with ultrasonic methodology, which is very effective in detecting altered and/or damaged zones both on the surface and inside the building materials of architectural elements. Analogies between TLS surface geometrical anomalies and the ultrasonic velocity field are evident at the surface and in shallow parts of the investigated architectural elements, as in the mentioned Pietra Cantone ancient portal. This study illustrates how the integrated application of TLS technology and the ultrasonic method contributes in overcoming ambiguities in the interpretation of the individual dataset. Therefore the methodology proposed in this study has proved to be effective in giving useful indications aimed at formulating a recovery and preservation plan for a monumental structure and to monitor its conservation status in time.
    Description: Copernicus Meetings
    Description: Published
    Description: Vienna | Austria | 17–22 April 2016
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Keywords: diagnostic techniques ; architectural elements ; ancient buildings ; structural damage ; preservation plan ; 04. Solid Earth ; Cultural Heritage
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    An integrated petrophysical-geophysical approach for the characterization of a potential caprock-reservoir system for CO2 storage. (2020)
    EGU - Copernicus
    Details
    Publication Date: 2020-05-19
    Description: The selection of a CO2 geologic storage site requires the choice of a study site suitable for the characterization in order to create a robust experimental database especially regarding the spatial petrophysical heterogeneities and elasto-mechanical properties of the rocks that make up a potential caprock-reservoir system. In our study the petrophysical and elasto-mechanical characterization began in a previously well drilled area in the northern part of the Sulcis coal basin (Nuraxi Figus area - SW Sardinia - Italy) where crucial geologic data were recovered from high-quality samples from stratigraphic wells and from mining galleries. The basin represents one of the most important Italian carbon reserves characterized by a great mining potential. In the study area, the Middle Eocene - Lower Oligocene Cixerri Fm. made up of terrigeneous continental rocks and the Upper Thanetian - Lower Ypresian Miliolitico Carbonate Complex in the Sulcis coal basin have been identified respectively as potential caprock and reservoir for CO2 storage. Petrophysical and geophysical investigations were carried out by a great number of laboratory tests on the core samples and in situ measurements on a mining gallery in order to characterize the potential caprock-reservoir system and to substantially reduce geologic uncertainty in the storage site characterization and in the geological and numerical modelling for the evaluation of CO2 storage capacity. In order to better define the spatial distribution of the petrophysical heterogeneity, the seismic responses from the caprock-reservoir system formations were also analysed and correlated with the petrophysical and elasto-mechanical properties In a second step of this work, we also analysed the tectonic stability of the study area by the integrated application of remote-sensing monitoring spatial geodetic techniques. In particular, the global positioning system (GPS) and interferometric synthetic aperture radar (inSAR) were considered useful tools to test the tectonic stability of the storage site. We computed the crustal strain rate of the Sulcis basin starting from the horizontal and vertical velocities detected by applying the two above remote sensing techniques. At the beginning we calculated the Eurasian intra-plate velocity and position time series of some good quality permanent GPS sites present in the study area. We then compared the computed GPS height variation of these sites with the line of sight (LOS) component of InSAR permanent scatters time series detected with the aid of the small baseline (SBAS) method and located closer to the GPS stations. The horizontal components show insignificant residual intra-plate velocities ranging between 0-1 mm/y, while the vertical velocities are comprised between 0 to 2 mm/y, testifying to the stability of the area. The same remote techniques mentioned above can be used during and after the injection of the CO2 to monitor the storage site. This remote monitoring option can be effective, cheap and repeatable.
    Description: Copernicus Meetings
    Description: Published
    Description: Vienna | Austria | 17–22 April 2016
    Description: 7A. Geofisica per il monitoraggio ambientale
    Keywords: elasto-mechanical characterization ; petrophysical heterogeneities ; caprock-reservoir system ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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    The 2020 coronavirus lockdown and seismic monitoring of anthropic activities in Northern Italy (2020)
    Nature P. G.
    Details
    Publication Date: 2020-06-11
    Description: In March/April 2020 the Italian government drastically reduced vehicle traffic and interrupted all non-essential industrial activities over the entire national territory. Italy thus became the first country in the world, with the exception of Hubei, to enact lockdown measures as a consequence of the COVID-19 outbreak and the need to contain it. Italy is also a seismically active area, and as such is monitored by a dense permanent network of seismic stations. We analyse continuous seismic data from many stations in northern and central Italy, and quantify the impact of the lockdown on seismic ambient noise, as a function of time and location. We find that the lockdown reduces ambient noise significantly in the 1–10 Hz frequency range; because natural sources of seismic noise are not affected by the lockdown, the seismic signature of anthropic noise can be characterised with unprecedented clarity, by simply comparing the signal recorded before and after the lockdown. Our results correlate well with independent evaluations of the impact of the lockdown (e.g., cell phone displacements), and we submit that ambient-noise seismology is a useful tool to monitor containment measures such as the coronavirus lockdowns.
    Description: European Union Horizon 2020 Research and Innovation Programme, grant agreements 802777-MONIFAULTS.
    Description: Published
    Description: 9404
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: ambient noise ; COVID-19 lockdown ; anthropic noise ; seismic monitoring ; 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Large-area quantification of subaerial CO2 anomalies with portable laser remote sensing and 2D tomography (2020)
    Details
    Publication Date: 2020-02-24
    Description: Quantifying subaerial fluxes of CO2 is key in a diverse range of applications, including carbon capture and storage sites, emissions from urban areas and industrial sites such as oil refineries, or forecasting volcanic eruptions. All of these have one thing in common: they represent spatially extended sources with a generally unknown spatial distribution of CO2 concentration. The conventional approach to measure CO2 fluxes is to first measure CO2 concentrations in situ at several points and estimate 2D CO2 concentration profiles. Along with the plume transport speed, the concentration profiles can then be used to compute CO2 fluxes. Active remote sensing of CO2 concentrations offers crucial advantages over in situ probing, including a spatially comprehensive measurement, a safe measurement distance, and faster acquisition, which enables real-time monitoring. This makes it also a viable complement or alternative to fence-line monitoring at industrial sites. In the last few years, technology has advanced sufficiently to allow for the realization of robust and portable remote sensing platforms that are relatively inexpensive and user friendly. Within the frameworks of the European Research Council CO2Volc and proof-of-concept CarbSens projects, such a remote sensing platform has been developed to probe CO2 emissions. It may be operated from a fixed location on the ground, from moving platforms (e.g., cars), or be airborne. The kit was used to probe CO2 concentrations and perform a feasibility test to obtain a tomographic 2D image of the subaerial CO2 distribution inside the Solfatara crater, part of arguably the most hazardous volcano in the world: Campi Flegrei near Naples, Italy. The methodology could be applied directly to industrial applications, including quantifying fugitive CO2 at storage and industrial sites. An unmanned aerial vehicle portable kit is envisaged.
    Description: Published
    Description: 306-313
    Description: 4V. Processi pre-eruttivi
    Description: N/A or not JCR
    Keywords: 04. Solid Earth ; 04.08. Volcanology ; 01.01. Atmosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Blind source separation problem in GPS time series (2020)
    Springer
    Details
    Publication Date: 2020-03-03
    Description: A critical point in the analysis of ground dis- placement time series, as those recorded by space geodetic techniques, is the development of data-driven methods that allow the different sources of deformation to be discerned and characterized in the space and time domains. Multivariate statistic includes several approaches that can be considered as a part of data-driven methods. A widely used technique is the principal component analysis (PCA), which allows us to reduce the dimensionality of the data space while maintain- ing most of the variance of the dataset explained. However, PCA does not perform well in finding the solution to the so-called blind source separation (BSS) problem, i.e., in recovering and separating the original sources that gener- ate the observed data. This is mainly due to the fact that PCA minimizes the misfit calculated using an L 2 norm (χ 2 ), look- ing for a new Euclidean space where the projected data are uncorrelated. The independent component analysis (ICA) is a popular technique adopted to approach the BSS problem. However, the independence condition is not easy to impose, and it is often necessary to introduce some approximations. To work around this problem, we test the use of a modi- fied variational Bayesian ICA (vbICA) method to recover the multiple sources of ground deformation even in the presence of missing data. The vbICA method models the probability density function (pdf) of each source signal using a mix of Gaussian distributions, allowing for more flexibility in the description of the pdf of the sources with respect to standard ICA, and giving a more reliable estimate of them. Here we present its application to synthetic global positioning system (GPS) position time series, generated by simulating deforma- tion near an active fault, including inter-seismic, co-seismic, and post-seismic signals, plus seasonal signals and noise, and an additional time-dependent volcanic source. We evaluate the ability of the PCA and ICA decomposition techniques in explaining the data and in recovering the original (known) sources. Using the same number of components, we find that the vbICA method fits the data almost as well as a PCA method, since the χ 2 increase is less than 10 % the value cal- culated using a PCA decomposition. Unlike PCA, the vbICA algorithm is found to correctly separate the sources if the correlation of the dataset is low (〈0.67) and the geodetic network is sufficiently dense (ten continuous GPS stations within a box of side equal to two times the locking depth of a fault where an earthquake of Mw 〉 6 occurred). We also provide a cookbook for the use of the vbICA algorithm in analyses of position time series for tectonic and non-tectonic applications.
    Description: Published
    Description: 323–341
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Isostasy, dynamic topography, and the elevation of the Apennines of Italy (2020)
    Elsevier
    Details
    Publication Date: 2020-03-03
    Description: The elevation of an orogenic belt is commonly related to crustal/lithosphere thickening. Here, we discuss the Apennines as an example to show that topography at a plate margin may be controlled not only by isostatic adjustment but also by dynamic, mantle-driven processes. Using recent structural constraints for the crust and mantle we find that the expected crustal isostatic component explains only a fraction of the topography of the belt, indicating positive residual topography in the central Apennines and negative residual topography in the northern Apennines and Calabria. The trend of the residual topography matches the mantle flow induced dynamic topography estimated from regional tomography models. We infer that a large fraction of the Apennines topography is related to mantle dynamics, producing relative upwellings in the central Apennines and downwellings in the northern Apennines and Calabria where subduction is still ongoing. Comparison between geodetic and geological data on vertical motions indicates that this dynamic process started in the early Pleistocene and the resulting uplift appears related to the formation and enlargement of a slab window below the central Apennines. The case of the Apennines shows that at convergent margins the elevation of a mountain belt may be significantly different from that predicted solely by crustal isostasy and that a large fraction of the elevation and its rate of change are dynamically controlled by mantle convection.
    Description: Published
    Description: 163-174
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: 04. Solid Earth ; 04.03. Geodesy
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    Bollettino Sismico Italiano maggio – agosto 2019 (2020)
    Details
    Publication Date: 2020-07-02
    Description: Gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, localizzati dal 1 MAGGIO AL 31 AGOSTO 2019. I parametri dei terremoti di magnitudo inferiore a tale soglia di revisione, sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; maggio - agosto 2019 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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    Bollettino Sismico Italiano settembre – dicembre 2019 (2020)
    Details
    Publication Date: 2020-07-20
    Description: DAL 1 SETTEMBRE AL 31 DICEMBRE 2019 la revisione della sismicità fatta dagli analisti del BSI ha riguardato tutti gli eventi di magnitudo M≥1.5. I parametri dei terremoti di magnitudo inferiore a tale soglia di revisione, sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma. Tutti gli eventi con M≥3.5, e pochi altri di particolare interesse (vedi Marchetti et al., 2016, DOI: 10.4401/ag-7169), sono stati rianalizzati dagli analisti del BSI, contestualmente al loro accadimento.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; settembre - dicembre 2019 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Bollettino Sismico Italiano gennaio – aprile 2019 (2020)
    Details
    Publication Date: 2020-05-25
    Description: Nel periodo che va dal 1 gennaio al 30 aprile 2019, gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, mentre i parametri dei terremoti di magnitudo inferiore a tale soglia di revisione sono stati calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; gennaio - aprile 2019 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
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    Bollettino Sismico Italiano settembre – dicembre 2018 (2020)
    Details
    Publication Date: 2020-05-25
    Description: Gli analisti del BSI hanno revisionato tutti gli eventi di magnitudo M≥1.5, localizzati dal 1 settembre al 31 dicembre 2018. I parametri dei terremoti di magnitudo inferiore a tale soglia di revisione, sono quelli calcolati in tempo reale, nella sala di sorveglianza sismica di Roma.
    Description: Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione Civile
    Description: Published
    Description: 4IT. Banche dati
    Keywords: Bollettino Sismico Italiano ; settembre - dicembre 2018 ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Spatio-temporal seismic velocity variations associated to the 2016–2017 central Italy seismic sequence from noise cross-correlation (2020)
    Details
    Publication Date: 2020-02-06
    Description: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2019. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Description: We investigate the temporal changes of crustal velocity associated to the seismic sequence of 2016–2017, which struck central Italy with a series of moderate to large earthquakes. We cross- correlate continuous recordings of 2 yr of ambient seismic noise from a network of 28 stations within a radius of 90 km around Amatrice town. We then map the spatio-temporal evolution of the velocity perturbations under the effect of subsequent earthquakes. Coinciding with each of the three main shocks of the sequence we observe a sudden drop of seismic velocity which tends to quickly recover in the short term. After the end of the strongest activity of the sequence, the coseismic velocity changes display gradual healing towards pre-earthquake conditions following a quasi-linear trend, such that by the end of 2017 about 75 per cent of the perturbation is recovered. The spatial distribution of the velocity drop fluctuates with time, and the area that shows the most intense variations beyond the ruptured fault system elongates in the NE direction. This zone roughly corresponds to a region of foredeep sedimentary deposits consisting of highly hydrated and porous sandstones, which respond to the passage of seismic waves with increased pore pressure and crack number, leading to a reduction of the effective relative velocity.
    Description: Published
    Description: 2165–2173
    Description: 7T. Variazioni delle caratteristiche crostali e precursori sismici
    Description: JCR Journal
    Keywords: seismic noise cross-correlations ; noise-based monitoring ; seismic velocity variations ; 04. Solid Earth ; 04.06. Seismology ; 05.01. Computational geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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