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  • 04.02. Exploration geophysics  (7)
  • Elsevier  (5)
  • Wiley  (2)
  • 2020-2023  (4)
  • 2020-2022  (3)
  • 1985-1989
  • 1970-1974
  • 1950-1954
  • 1
    Publikationsdatum: 2022-03-21
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 228811
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: JCR Journal
    Schlagwort(e): Carbonate faults ; Fault slip behavior ; 04.02. Exploration geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    facet.materialart.
    Unbekannt
    Elsevier
    Publikationsdatum: 2022-02-10
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 675-688
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: 1V. Storia eruttiva
    Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani
    Beschreibung: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Beschreibung: 1A. Geomagnetismo e Paleomagnetismo
    Beschreibung: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare
    Beschreibung: 5A. Ricerche polari e paleoclima
    Beschreibung: 7A. Geofisica per il monitoraggio ambientale
    Beschreibung: 1TR. Georisorse
    Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale
    Beschreibung: 6SR VULCANI – Servizi e ricerca per la società
    Beschreibung: 7SR AMBIENTE – Servizi e ricerca per la società
    Schlagwort(e): 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)
    Materialart: book chapter
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2021-06-14
    Beschreibung: Southwestern Sicily is an area of infrequent seismic activity; however, some studies carried out in the archaeological Selinunte site suggest that, between the fourth century BC and the early Middle Ages, probably at least two earthquakes strucked this area with enough energy to damage and cause the collapse and kinematics of much of the architecture of Selinunte. Take into account that, in 2008, a noninvasive archaeological prospection and traditional data gathering methods along the Acropolis north fortifications were carried out. Following these first studies, after about 10 years, a new geophysical campaign was carried out. This second campaign benefited from the application of modern technologies for the acquisition and processing of the point cloud data on the northern part of the Acropolis, like terrestrial laser scanning and unmanned aerial vehicle photogrammetry. In this paper, we present the application of these techniques and a strategy for their integration for the 3D modelling of buildings and cultural heritages. We show how the integration of data acquired independently by these two techniques is an added value able to overcome the intrinsic limits of the individual techniques. The application to Selinunte's Acropolis allowed it to highlight and measure with high accuracy fractures, dislocation, inclinations of walls, depressions of some areas and other interesting observations, which may be important starting points for future investigations.
    Beschreibung: Published
    Beschreibung: 153-165
    Beschreibung: 2IT. Laboratori analitici e sperimentali
    Beschreibung: JCR Journal
    Schlagwort(e): 3D reconstruction ; archaeological survey ; digital elevation model ; Selinunte Archaeological Park ; terrestrial laser scanning ; unmanned aerial vehicle photogrammetry ; 05.04. Instrumentation and techniques of general interest ; 04.02. Exploration geophysics ; 05.02. Data dissemination ; 05.06. Methods
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2021-12-09
    Beschreibung: Rome Capital City is located in a high heat flux area of central Italy, suitable for low-enthalpy geothermal exploitation. In the central-northern part of the city, near Tor di Quinto hippodrome close to Tiber River, a wide undeveloped area occurs, which is a possible future urban development site. We present the results of a geochemical and geophysical study aimed at assessing the presence in this zone of a low-enthalpy geothermal aquifer and at evaluating its depth, thickness and the physico-chemical characteristics of the geothermal water. Furthermore the natural CO2 output of this zone has been investigated. A soil CO2 flux survey with 551 measurements over a surface of 3.09 km2 revealed the presence of parallel NW-SE trending positive flux anomalies. The total CO2 output was estimated to 87.77 t*day-1, most of which (85 %) of endogenous or mixed origin. An Electrical Resistivity Tomography survey, consisting of five parallel 355 m long and 100 m spaced profiles, allowed the reconstruction of the stratigraphy of the underground sediments, which are fluvial deposits of the near Tiber River. The geothermal water is hosted in a low-resistivity layer, corresponding to the Tiber base gravels, which are here 20 m thick and whose top is 40 m below the surface. The water has a nearly constant temperature of 17.5 °C, a relatively high salinity and an appreciable content in dissolved gas. This low-enthalpy resource is suitable for direct uses, e.g. individual and district heating/cooling, sanitary hot water, spa facilities for swimming and bathing.
    Beschreibung: This work was partially supported by the INGV AMUSED research project (CUP D59C19000100005)
    Beschreibung: Published
    Beschreibung: 102298
    Beschreibung: 6A. Geochimica per l'ambiente e geologia medica
    Beschreibung: JCR Journal
    Schlagwort(e): Low enthalpy geothermal aquifer Rome ; water chemistry ; diffuse soil CO2 output ; Electrical Resistivity Tomography ; 04.08. Volcanology ; 04.02. Exploration geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2021-01-08
    Beschreibung: Soil gas and Electrical Resistivity Tomography (ERT) surveys were performed in Medolla (Emilia-Romagna Region, northern Italy) within a farming area characterized by macroseeps, absence of vegetation and anomalous temperatures of soil to investigate the soil gas migration mechanism and verify the presence of a buried fault intersecting the macroseeps. Soil gas (222Rn, 220Rn, He and C2H6) concentrations and flux (φCO2 and φCH4) measurements were carried out from 2008 to 2015, comprising the 2012 Emilia seismic sequence. Moreover, in 2016 a ERT survey, combined with new flux measurements, was performed along four profiles (ranging from 180 to 630 m long) centered on the main macroseep. We found that the seismic sequence sensibly influenced the soil gas distribution in the area. All investigated species, but He, increased their values early after the mainshocks, likely due to crustal deformation which promoted the geogas uprising. In 2015, when the stress has vanished, these concentrations gradually decreased toward pre-seismic values. Helium concentrations showed an opposite behavior as they decreased in May 2012 and then gradually increased over time. This trend may be reasonably due to the enhancement of the strain field which promoted the He dissipation from soil to the atmosphere, due to its high volatility. In all the geochemical surveys conducted from 2008 to 2015, soil gas high values around the main macroseeps were identified, delighting the presence of an alignment in the E-W direction. This trend, identified for several gas species, ultimately supports the theory of a hidden fault which favors the intensification of fluids migration along zones characterized by greater permeability. ERT results highlighted a sub-horizontal layering characterized by different resistivity intervals, roughly matching local stratigraphy. In most profiles we observed a slightly increase of resistivity and a sharp inter-ruption of the electro-layering in correspondence of the main macroseep, both near the surface and at depth. This implies that a fracture zone due to the presence of a buried fault cannot be excluded. The combined use of geochemical and geophysical techniques in this study confirmed the usefulness of such multiparametric approach for mapping out hidden structures in tectonically active areas, allowing to better understanding the fluid migration processes through preferential leakage pathways.
    Beschreibung: Published
    Beschreibung: 106678
    Beschreibung: 6A. Geochimica per l'ambiente e geologia medica
    Beschreibung: 7A. Geofisica per il monitoraggio ambientale
    Beschreibung: JCR Journal
    Schlagwort(e): Soil gas survey ; Electrical Resistivity Tomography (ERT) survey ; Migration pathways ; Medolla ; 04.02. Exploration geophysics ; 03.04. Chemical and biological
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2020-07-08
    Beschreibung: The response of continental forelands to subduction and collision is a widely investigated topic in geodynamics. The deformation occurring within a foreland shared by two opposite‐verging chains, however, is uncommon and poorly understood. The Apulia Swell in the southern end of the Adria microplate (Africa‐Europe plate boundary, central Mediterranean Sea) represents one of these cases, as it is the common foreland of the SW verging Albanides‐Hellenides and the NE verging Southern Apennines merging into the SSE verging Calabrian Arc. We investigated the internal deformation of the Apulia Swell using multiscale geophysical data: multichannel seismic profiles recording up to 12‐s two‐way time (TWT) for a consistent image of the upper crust; high‐resolution multichannel seismic profiles, high‐resolution multibeam bathymetry, and CHIRP profiles acquired by R/V OGS Explora to constrain the Quaternary geological record. The results of our analyses characterize the geometry of the South Apulia Fault System (SAFS), a 100‐km‐long and 12‐km‐wide structure attesting an extensional (and possibly transtensional) response of the foreland to the two contractional fronts. The SAFS consists of two NW‐SE right‐stepping master faults and several secondary structures. The SAFS activity spans from the Early Pleistocene through the Holocene, as testified by the bathymetric and high‐resolution seismic data, with long‐term slip rates in the range of 0.2–0.4 mm/yr. Considering the position within an area with few or none other active faults in the surroundings, the dimension, and the activity rates, the SAFS can be a candidate causative fault of the 20 February 1743, M 6.7, earthquake.
    Beschreibung: Italian Ministry for Education, University, and Research (MIUR), Premiale 2014 D. M. 291 03/05/2016.
    Beschreibung: Published
    Beschreibung: e2020TC006116
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale
    Beschreibung: JCR Journal
    Schlagwort(e): active tectonics ; apulia ; south apulia fault system ; 1743 earthquake ; marine geology ; stable continental region ; ionian sea ; active faults ; subsurface geology ; seismic interpretation ; 04.04. Geology ; 04.07. Tectonophysics ; 04.02. Exploration geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2022-06-09
    Beschreibung: Joint analysis of high-penetration multi-channel and high-resolution single-channel seismic reflection profiles, calibrated by deep well boreholes, allowed a detailed reconstruction of the Late Miocene to Recent tectonic history of the Capo Granitola and Sciacca fault systems offshore southwestern Sicily. These two fault arrays are part of a regional system of transcurrent faults that dissect the foreland block in front of the Neogene Sicilian fold and thrust belt. The Capo Granitola and Sciacca faults are thought to reactivate inherited Mesozoic to Miocene normal faults developed on the northern continental margin of Africa. During Latest Miocene-Pliocene, the two ~NNE-SSW striking faults were active in left transpression, which inverted Late Miocene extensional half-grabens and created push-up ridges along both systems. Tectonic activity decreased during the Pleistocene, but transpressional folds deform Middle-Late Pleistocene sediments as well, suggesting that the two fault systems are active. The ~40 km long longitudinal amplitude profile of 1st order folds (Capo Granitola and Sciacca anticlines) shows ~15–20 km bell-shaped undulations that represents 2nd order folds. The length of these undulations together with the map pattern of faults allowed to divide the CGFS and SFS into two segments, northern and southern, respectively. Total uplift of the Sciacca Anticline is twice than the uplift of the Capo Granitola Anticline. Incremental fold growth rates decreased during time from 0.22 mm/yr (Capo Granitola Anticline) and 0.44 mm/yr (Sciacca Anticline) in the Pliocene, to 0.07 and 0.22 mm/yr, respectively, during the last ~1.8 Ma.
    Beschreibung: Published
    Beschreibung: 187-204
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare
    Beschreibung: JCR Journal
    Schlagwort(e): Multiscale analysis ; Basin inversion ; Strike-slip faults ; Fold growth rates ; Pelagian foreland ; SW Sicily offshore ; 04.07. Tectonophysics ; 04.04. Geology ; 04.02. Exploration geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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