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  • 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks  (25)
  • 04. Solid Earth::04.04. Geology::04.04.09. Structural geology  (22)
  • Elsevier  (27)
  • Geological Society of America  (12)
  • Elsevier B.V.  (5)
  • The Geological Society of London  (2)
  • MDPI Publishing
  • Nature Publishing Group
  • 2010-2014  (47)
Collection
Keywords
Publisher
Years
Year
  • 1
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    Hyaloclastite fragmentation below the glass transition: An example from El Barronal submarine volcanic complex (Spain) (2014)
    Geological Society of America
    Details
    Publication Date: 2020-12-14
    Description: Submarine felsic volcanoes are dominated by hyaloclastic piles hundreds of meters thick, the origin of which, in terms of how and when they form, is far from being completely understood. Here we present a study of the thermal remanent magnetization of the Miocene high-K dacitic El Barronal hyaloclastites (Cabo de Gata, Spain), showing that their formation is dominated by in situ fragmentation with small or negligible transportation and/or rotation of different clasts after their formation. Data indicate that fragmentation progressed down to 210–390 °C, well below the glass-transition temperature estimated at 560–750 ºC depending on the water content of the high-K dacite. Hence, hyaloclastite fragmentation in thick lavas may occur over most of the cooling history, as a result of the progressive access of sea water toward the lava interior by development of a complex network of contraction fractures.
    Description: Published
    Description: 87-90
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: hyaloclastite ; volcanic fragmentation ; thermal magnetization ; Cabo de Gata ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Magnetic fabric of Plio-Pleistocene sediments from the Crotone fore-arc basin: Insights on the recent tectonic evolution of the Calabrian Arc (Italy) (2014)
    Elsevier
    Details
    Publication Date: 2020-12-07
    Description: Low-field anisotropy of magnetic susceptibility (AMS) analyses were performed on 532 samples col-lected in 36 (mostly lower Pliocene to lower Pleistocene) marine clay sites from the Crotone basin, afore-arc basin located on top of the external Calabrian accretionary wedge. The Crotone basin formedsince mid-late Miocene under a predominant extensional tectonic regime, but it was influenced there-after by complex interactions with NW–SE left-lateral strike-faults bounding the basin, which also yieldedpost-1.2 Ma ~30◦counterclockwise block rotations. The basin is filled by continental to marine sedimentsyielding one of the thickest and best-exposed Neogene succession available worldwide. The deep-marinefacies – represented by blue-grey marly clays gave the best results, as they both preserved a clear mag-netic fabric, and provided accurate chronology based on previously published magnetostratigraphy andcalcareous plankton (i.e. foraminifers and nannofossils) biostratigraphy. Magnetic susceptibility rangeand rock magnetic analyses both indicate that AMS reflects paramagnetic clay matrix crystal arrange-ment. The fabric is predominantly oblate to triaxial, the anisotropy degree low (〈1.06), and the magneticfoliation mostly subparallel to bedding. Magnetic lineation is defined in 30 out of 36 sites (where thee12 angle is 〈35◦). By also considering local structural analysis data, we find that magnetic fabric wasgenerally acquired during the first tectonic phases occurring after sediment deposition, thus validatingits use as temporally dependent strain proxy. Although most of the magnetic lineations trend NW–SE andare orthogonal to normal faults (as observed elsewhere in Calabria), few NE–SW compressive lineationsshow that the Neogene extensional regime of the Crotone basin was punctuated by compressive episodes.Finally, compressive lineations (prolate magnetic fabric) documented along the strike-slip fault boundingthe basin to the south support the significance of Pleistocene strike-slip tectonics. Thus the Crotone basinshows a markedly different tectonics with respect to other internal and western basins of Calabria, asit yields a magnetic fabric still dominated by extensional tectonics but also revealing arc-normal short-ening episodes and recent strike-slip fault activity. The tectonics documented in the Crotone basin iscompatible with a continuous upper crustal structural reorganization occurring during the SE-migrationof the Calabria terrane above the Ionian subduction system.
    Description: Published
    Description: 67-79
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Calabrian Arc, Anisotropy of magnetic susceptibility, Structural analysis, Fore-arc region ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Carbonate-derived CO2 purging magma at depth: Influence on the eruptive activity of Somma-Vesuvius, Italy (2012)
    Elsevier
    Details
    Publication Date: 2020-11-30
    Description: Mafic phenocrysts from selected products of the last 4 ka volcanic activity at Mt. Vesuvius were investigated for their chemical and O-isotope composition, as a proxy for primary magmas feeding the system. 18O/16O ratios of studied Mg-rich olivines suggest that near-primary shoshonitic to tephritic melts experienced a flux of sedimentary carbonate-derived CO2, representing the early process of magma contamination in the roots of the volcanic structure. Bulk carbonate assimilation (physical digestion) mainly occurred in the shallow crust, strongly influencing magma chamber evolution. On a petrological and geochemical basis the effects of bulk sedimentary carbonate digestion on the chemical composition of the near-primary melts are resolved from those of carbonate-released CO2 fluxed into magma. An important outcome of this process lies in the effect of external CO2 in changing the overall volatile solubility of the magma, enhancing the ability of Vesuvius mafic magmas to rapidly rise and explosively erupt at the surface.
    Description: Published
    Description: 84-95
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: stable-isotope ; magma geochemistry ; CO2-degassing ; Vesuvius ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Easternmost Mediterranean evidence of the Zanclean flooding event and subsequent surface uplift: Adana Basin, southern Turkey (2012)
    The Geological Society of London
    Details
    Publication Date: 2021-04-07
    Description: According to the literature, the Adana Basin, at the easternmost part of the Mediterranean Basin in southern Turkey, records the Pliocene stage with shallow-marine to fluvial deposits. Our micropalaeontological analysis of samples from the Adana Basin reveal Late Lago–Mare biofacies with Paratethyan ostracod assemblages pertaining to the Loxocorniculina djafarovi zone. Grey clays rich in planktonic foraminifera lie above the Lago–Mare deposits. Within the grey clays, the continuous occurrence of the calcareous nannofossil Reticulofenestra zancleana and the base of the Reticulofenestra pseudoumbilicus paracme points to an Early Zanclean age (5.332–5.199 Ma). Both ostracod and benthic foraminifera indicate epibathyal and bathyal environments. 87Sr/86Sr measurements on planktonic and benthic foraminifera fall below the mean global ocean value for the Early Zanclean, indicating potentially insufficient mixing of low 87Sr/86Sr Mediterranean brackish ‘Lago–Mare’ water with the global ocean in the earliest Pliocene.We utilize the ages and palaeodepths of the marine sediments together with their modern elevations to determine uplift rates of the Adana Basin of 0.06 to 0.13 mm a21 since 5.2–5.3 Ma (total uplift of 350–650 m) from surface data, and 0.02–0.13 mm a21 since c. 1.8 Ma (total uplift of 30–230 m) from subsurface data.
    Description: Published
    Description: 3.2. Tettonica attiva
    Description: N/A or not JCR
    Description: restricted
    Keywords: Lago–Mare deposits ; Adana Basin ; southern Turkey ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 5
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    A study on the reproducibility of counting vesicles in volcanic rocks (2012)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: Vesicle size distributions in two and three dimensions of two samples were independently measured by three different researchers to investigate whether or not such measurements are reproducible. Additionally, two different software programs were used to measure the three-dimensional vesicle size distributions: the 3D Object Counter plugin for ImageJ and Blob3D. Manual thresholding by each of the authors produced similar results for both samples using both programs; however, use of the automatic, maximum entropy technique for thresholding produced measurably different results because it did not discriminate between vesicles and plagioclase crystals in one case and between vesicles and some cracks in another. Use of asymmetric erosion and dilation processes on the images is shown to affect the vesicle size distribution, but it does not have a significant effect on the power-law exponent that describes intermediate-sized vesicles or on the vesicle number density in these samples. However, such a technique is not recommended.
    Description: Published
    Description: 70-78
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Volcanic rocks ; vesicle counting ; reproducibility ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Vein development during folding in the upper brittle crust: The case of tourmaline-rich veins of eastern Elba Island, northern Tyrrhenian Sea, Italy (2012)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Detailed structural analysis of tourmaline-rich veins hosted in the contact aureole of the ∼6 Ma Porto Azzurro granite in southeastern Elba Island, northern Tyrrhenian Sea is presented. Using geometric features of the veins, the physical conditions at the time of vein formation are estimated, namely the stress ratio (Φ = (σ2 − σ3)/(σ1 − σ3)), driving stress ratio (R′ = (Pf − σ3)/(σ1 − σ3)) and fluid overpressure (ΔPo = Pf − σ3). Two vein sets (A veins and B veins) have been recognized based on orientation and thickness distributions and infilling material. Analysis of vein pole distributions indicates Φ = 0.57 and R′ = 0.24 for the A veins and Φ = 0.58 and R′ = 0.47 for the B veins, and fluid pressures less than the intermediate stress magnitude. Analysis of geometric features of the veins gives estimated fluid overpressures of between ∼16 MPa (A veins) and ∼32 MPa (B veins). We propose a model for the tectonic environment of vein development, in which formation of secondary permeability in the deforming thermal aureole of the Porto Azzurro pluton was controlled by ongoing development of fracture systems in the hinge zone of a regional NNW–SSE trending fold that favored transport and localization of hydrothermal fluids.
    Description: Published
    Description: 1509-1522
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Thermal aureole ; Upper crust ; Deformation ; Fluid circulation ; Northern Apennines ; Elba Island ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Fault architecture in the Main Ethiopian Rift and comparison with experimental models: Implications for rift evolution and Nubia–Somalia kinematics (2012)
    Elsevier
    Details
    Publication Date: 2020-05-28
    Description: The Main Ethiopian Rift (MER) offers a complete record of the time–space evolution of a continental rift. We have characterized the brittle deformation in different rift sectors through the statistical analysis of a new database of faults obtained from the integration between satellite images and digital elevation models, and implemented with field controls. This analysis has been compared with the results of lithospheric-scale analogue models reproducing the kinematical conditions of orthogonal and oblique rifting. Integration of these approaches suggests substantial differences in fault architecture in the different rift sectors that in turn reflect an along-axis variation of the rift development and southward decrease in rift evolution. The northernmost MER sector is in a mature stage of incipient continental rupture, with deformation localised within the rift floor along discrete tectono-magmatic segments and almost inactive boundary faults. The central MER sector records a transitional stage in which migration of deformation from boundary faults to faults internal to the rift valley is in an incipient phase. The southernmost MER sector is instead in an early continental stage, with the largest part of deformation being accommodated by boundary faults and almost absent internal faults. The MER thus records along its axis the typical evolution of continental rifting, from fault-dominated rift morphology in the early stages of extension toward magma-dominated extension during break-up. The extrapolation of modelling results suggests that a variable rift obliquity contributes to the observed along-axis variations in rift architecture and evolutionary stage, being oblique rifting conditions controlling the MER evolution since its birth in the Late Miocene in relation to a constant post ca. 11 Ma ~ N100°E Nubia–Somalia motion.
    Description: Published
    Description: 479-492
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: continental rifting ; East African Rift ; Main Ethiopian Rift ; rift kinematics ; plate kinematics ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Texture analysis of volcanic rock samples: Quantitative study of crystals and vesicles shape preferred orientation from X-ray microtomography data (2012)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In the texture analysis of volcanic rocks, the preferred orientation of the constituents can provide useful information for the interpretation of the processes involved in the rock formation. We present here a new data analysis technique, based on X-ray microtomography measurements and on shape preferred orientation analysis, to obtain the orientation distribution functions of the constituents of volcanic rocks. This procedure proved to be very suitable for volcanic samples, where diffraction-based techniques, developed for crystallographic preferred orientation studies, are of limited utilization, in addition to the fact that they cannot provide any information about vesicles or bubbles. Moreover the analysis performed directly in three dimensions (3D) overcomes the problems that usually occur when employing stereological methods for the analysis of the images obtained via microscopy-based techniques. In this study, two scoriae (from Stromboli and Etna) and a tube pumice (from Campi Flegrei) were measured via X-ray microtomography and then the resulting volumes were analyzed following the proposed procedure. Results highlight little preferred orientation for the vesicles in the two scoria samples, whereas the pumice shows a marked preferred orientation. Crystals (also divided by mineral species) were taken into account as well and in the two scoria samples there is no crystal preferred orientation, in contrast with the pumice, where crystal preferred orientation features are very similar to the ones found for the vesicles. Overall we found strong differences in preferred orientation: weak for vesicles in scoriae, showing an axial symmetry with the axis parallel to the elongation axis of the sample, and a stronger and more complex orientation texture in the pumice sample for both crystals and vesicles. The promising results obtained suggest that this procedure is potentially very useful for the analysis of preferred orientation in volcanic rocks and geomaterials in general.
    Description: Published
    Description: 83-95
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: X-ray computed microtomography ; preferred orientation ; texture analysis ; volcanic scoria ; synchrotron X-rays ; pumice ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Early Miocene volcanic activity and paleoenvironment conditions recorded in tephra layers of the AND-2A core (southern McMurdo Sound, Antarctica) (2012)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: The ANtarctic geological DRILLing program (ANDRILL) successfully recovered 1138.54 m of core from drillhole, AND-2A, in the Ross Sea sediments (Antarctica). The core is composed of terrigenous claystones, siltstones, sandstones, conglomerates, breccias, and diamictites with abundant volcanic material. In this work we present sedimentological, morphoscopic, petrographic, and geochemical data on pyroclasts recovered from core AND-2A, which provide insights on eruption styles, volcanic sources, and environments of deposition. One pyroclastic fall deposit, 12 resedimented volcaniclastic deposits and 14 volcanogenic sedimentary deposits record a history of intense explosive volcanic activity in southern Victoria Land during the Early Miocene. Tephra were ejected during Subplinian and Plinian eruptions fed by trachytic to rhyolitic magmas and during Strombolian to Hawaiian eruptions fed by basaltic to mugearitic magmas in submarine/subglacial to subaerial environments. The long-lived Mt. Morning eruptive centre, located c. 80 km south of the drillsite, was recognized as the probable volcanic source for these products on the basis of volcanological, geochemical, and age constraints. The study of tephra in the AND-2A core provides important paleoenvironment information by revealing that the deposition of primary and moderately reworked tephra occurred in a proglacial setting under generally open water marine conditions.
    Description: Published
    Description: 1342-1355
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: partially_open
    Keywords: Antarctica ; Volcaniclastic sediments ; Paleoenvironment ; Mt. Morning ; Victoria Land Basin ; 02. Cryosphere::02.03. Ice cores::02.03.05. Paleoclimate ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Introduction: The ANDRILL McMurdo Ice Shelf (MIS) and Southern McMurdo Sound (SMS) Drilling Projects (2012)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: No Abstract
    Description: Published
    Description: 546-547
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Stratigraphic Drilling ; McMurdo Ice Shelf ; Chronostratigraphy ; Neogene ; Tectonics ; Ice Sheet history ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Neogene deformation and granite emplacement in the metamorphic units of northern Apennines (Italy): Insights from mylonitic marbles in the Porto Azzurro pluton contact aureole (Elba Island) (2012)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: In the northern Tyrrhenian Sea, late Miocene intrusions (Monte Capanne pluton and Porto Azzurro pluton) were emplaced at upper crustal levels (〈0.2 GPa) in the thrust systems of Elba Island. The emplacement of intrusive rocks is currently explained in the context of late Miocene extensional tectonics. New detailed structural data collected along a continuous natural cross section through the contact aureole of the Porto Azzurro pluton (eastern Elba) where strain localization has occurred within two west-dipping decameter-scale carbonate shear zones, namely the Calanchiole and Felciaio shear zones, are reported here. These shear zones, characterized by a lithological difference with calcite and dolomite marbles dominant in the Calanchiole and Felciaio shear zones, respectively, exhibit a similar rheological behavior. They represent two weakened layers in which west-dipping mylonitic foliation, sheath folds, boudinage structures, and upright folds developed within the contact aureole. Moreover, in correspondence with the Felciaio shear zone, the inversion of metamorphic facies occurs. Meso- and microstructural data give evidence that most of the deformation and displacement in the shear zones was coeval with contact metamorphism and developed under metamorphic conditions retrograde from pyroxene hornfels to hornblende-hornfels facies. Geometric and kinematic features indicate that both shear zones correspond to ductile thrusts, which led to internal stacking of the contact aureole. Therefore, at Elba Island, emplacement of intrusive rocks coeval with late Miocene crustal shortening gives a new perspective on relations between tectonics and magmatism in the northern Apennines.
    Description: Published
    Description: 470-490
    Description: 1.10. TTC - Telerilevamento
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: granite emplacement ; contact aureole ; deformation and metamorphism ; Neogene ; northern Apennines ; Elba Island ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Rapid differentiation in a sill-like magma reservoir: a case study from the campi flegrei caldera (2012)
    Nature Publishing Group
    Details
    Publication Date: 2017-04-04
    Description: In recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thus on their differentiation histories. In this study, by using geochemical, isotopic and textural records of rocks erupted from the high-risk Campi Flegrei caldera, we show that the alkaline magmas have evolved toward a critical state of explosive behaviour over a time span shorter than the repose time of most volcanic systems and that these magmas have risen rapidly toward the surface. Moreover, similar results on the depth and timescale of magma storage were previously obtained for the neighbouring Somma-Vesuvius volcano. This consistency suggests that there might be a unique long-lived magma pool beneath the whole Neapolitan area.
    Description: Published
    Description: article 712
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: N/A or not JCR
    Description: open
    Keywords: magma ; campi flegrei caldera ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 13
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    Rock magnetism and compositional investigation of Brown Tuffs deposits at Lipari and Vulcano (Aeolian Islands — Italy) (2012)
    Elsevier
    Details
    Publication Date: 2021-12-06
    Description: A rock-magnetic investigation was carried out on the nonwelded ash deposits of the Brown Tuffs (Aeolian Islands, southern Tyrrhenian Sea) to improve the stratigraphic correlation between the deposits cropping out on Lipari and Vulcano islands and locate their source area. The study was supplemented by petrographical and geochemical analyses on selected strata, with the intent to compare the Brown Tuffs to other rocks emplaced at Vulcano in the same time span. More than 30 levels were sampled in the intermediate (56± 4 kaNIBTN21–22 ka) and upper (21–22 kaNUBT) parts of the Brown Tuffs sequences on the two islands. Their characteristic remanent magnetization (ChRM) directions were derived from stepwise thermal demagnetization, and the magnetic fabric from measurements of the anisotropy of magnetic susceptibility. The levels with indistinguishable ChRM directions were regarded as coeval and to form an individual stratigraphic unit. The units were referred to the Brown Tuffs sequence of Lucchi et al. (2008) on the grounds of their emplacement age, provided by comparison of their mean paleomagnetic direction with the paleosecular variation curves of the southern Tyrrhenian region, as well as the field constraints. The closer correlation between the sequences of Lipari and Vulcano contributes to a better understanding of the volcanic activity that produced the Brown Tuffs, and shows that most of the IBT and the oldest UBT levels were emplaced in a short time span, between ≈24 and 20–17 ka. The magnetic fabric is typically well developed, but at most sites the magnetic foliation is very close to horizontal and no imbrication is defined. The source area of the Brown Tuffs parent pyroclastic flows, as constrained from the intersection of the magnetic lineations, falls in the northeastern part of La Fossa Caldera structure. Although limited to major elements, compositional data provide further indication about the parent plumbing system and its behaviour. Magma batch(es) involved in the IBT eruptions have homogeneous features and underwent frequent refilling and tapping processes. Conversely, those involved in the early UBT eruptions are compositionally more variable. This suggests more complex evolution and plumbing system activity: the UBT eruptions represent either residual mafic magmas from the previous eruptions or the arrival of new, fresh shoshonitic magma in the system.
    Description: Published
    Description: 23-38
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Brown Tuffs ; Magnetic fabric ; pyroclastic rocks ; Aeolian Islands ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Dynamic plumbing system beneath volcanoes revealed by kinetic modeling, and the connection to monitoring data: An example from Mt. Etna (2012)
    Elsevier
    Details
    Publication Date: 2023-01-27
    Description: Our ability to monitor volcanoes (using seismic signals, ground deformation, gas fluxes, or other ground and satellite based observations) as well as our understanding of melt reservoirs that feed eruptions have evolved tremendously in recent years. The complex plumbing systems that are thought to feed eruptions are, however, difficult to relate to the monitoring signals. Here we show that the record preserved in compositional zoning of erupted minerals may be used to reconstruct sections of the plumbing system. Kinetic modeling of such zoning can yield information on the residence time of magma in different segments of the plumbing systems. This allows a more nuanced evaluation of the link between observed monitoring signals or eruption styles and the magmatic processes and movement of batches of melts at depth. The approach is illustrated through a study of the compositional zoning recorded in olivine crystals from the 1991–1993 SE-flank eruption products of Mt. Etna (Sicily). The zoning patterns in crystals reveal that the plumbing system of the volcano consisted of at least three different magmatic environments between which magma was transported and mixed in the year or two preceding the start of eruption. Quantification of this history indicates that two main pathways of melt migration and three timescales dominated the dynamics of the system. Combination of this information with the timing of observation of various monitoring signals allows a reconstruction of the dynamic evolution of this section of the plumbing system during the early stages of the 1991–1993 eruption. It is seen, for example, how the migration of melt through the same sections of the plumbing system can cause pre-eruptive triggering, enhance Strombolian activity, and through the ensuing eruption cleanse and flush the plumbing system. Different kinds of mixing occur simultaneously at different sections of the plumbing system on different timescales (a few days up to two years).
    Description: Published
    Description: 11-22
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; plumbing system ; olivine ; zoning ; timescales ; monitoring ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
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    Self-similar clustering of cinder cones and crust thickness in the Michoacan–Guanajuato and Sierra de Chichinautzin volcanic fields, Trans-Mexican Volcanic Belt (2011)
    Elsevier
    Details
    Publication Date: 2021-04-20
    Description: The spatial clustering of basaltic vents in monogenetic volcanic fields has been used as a proxy for crustal thickness in extensional and back-arc tectonic settings. The basaltic vents have a fractal clustered distribution (self-similar clustering) described by a power-law. The power-law is defined over a range, the size range of the distribution, of values (in this case the vents' separation) delimited by a lower and an upper cut-offs. Here we apply the fractal clustering analysis to the two largest monogenetic volcanic fields of the Trans-Mexican Volcanic Belt (TMVB), a continental arc built on different crustal terranes. The Michoacan–Guanajuato volcanic field (MGVF), located in the central-western TMVB, includes over 1000 vents of late Pliocene to Quaternary age, built on attenuated crust of Mesozoic to Tertiary age. The Sierra de Chichinautzin volcanic field (SCVF), in the central-eastern TMVB, is composed of ~ 220 Late Pleistocene to Holocene vents laying above thicker crust of Precambrian to Tertiary age. Monogenetic vents in both volcanic fields show self-similar clustering with fractal exponent D = 1.67 in the range 1.3–38 km (MGVF) and D = 1.56 in the range 1.5–32 km (SCVF). The upper cut-off (Uco) for the power-law distribution of the MGVF well fits the crustal thickness below the volcanic field as derived from independent geophysical data. The Uco value of SCVF indicates a crust thickness of about 32 km, this value is in agreement with new geophysical data that indicate magma underplating the crust beneath the volcanic field area.
    Description: Published
    Description: 55-64
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Volcanic fields ; Tectonic ; Vent distribution ; Crust thickness ; Mexico ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 16
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    Quantitative analysis of X-ray microtomography images of geomaterials: Application to volcanic rocks (2011)
    Geological Society of America
    Details
    Publication Date: 2021-01-27
    Description: X-ray computed microtomography is an excellent tool for the three-dimensional analysis of rock microstructure. Digital images are acquired, visualized, and processed to identify and measure several discrete features and constituents of rock samples, by means of mathematical algorithms and computational methods. In this paper, we present digital images of volcanic rocks collected with X-ray computed microtomography techniques and studied by means of a software library, called Pore3D, custom-implemented at the Elettra Synchrotron Light Laboratory of Trieste (Italy). Using the Pore3D software, we analyzed the fabrics and we quantified the characteristics of the main constituents (vesicles, crystals, and glassy matrix) of four different types of pyroclasts: frothy pumice, tube pumice, scoria, and “crystalline” scoria. We identified the distinctive features of these different types of volcanic rocks. The frothy pumices show vesicles that coalesce in isotropic aggregates, especially toward the sample interior, while the scoriae have a low porosity and an abundance of isolated vesicles. In the “crystalline” scoria sample most of the vesicle separation is due to the presence of crystals of different types, while the tube pumice shows an anisotropic distribution of vesicles and crystals at the microscale, as also observed at the scale of the hand sample. Quantitative analysis and textural information may supply an additional tool to investigate the eruptive processes and the origin of volcanic rocks.
    Description: Published
    Description: 793-804
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: X-ray tomography ; 3D imaging ; volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 17
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    The growth and erosion of cinder cones in Guatemala and El Salvador: Models and statistics (2011)
    Elsevier B.V.
    Details
    Publication Date: 2020-11-18
    Description: Morphologic data for 147 cinder cones in southern Guatemala andwestern El Salvador are comparedwith data from the San Francisco volcanic field, Arizona (USA), Cima volcanic field, California (USA), Michoácan–Guanajuato volcanic field, Mexico, and the Lamongan volcanic field, East Java. The Guatemala cones have an average height of 110+/-50 m, an average basal diameter of 660+/-230 m and an average top diameter of 180+/-150 m. The generalmorphology of these cones can be described by their average cone angle of slope (24+/-7), average heightto- radius ratio (0.33+/-0.09) and their flatness (0.24+/-0.18). Although the mean values for the Guatemalan cones are similar to those for other volcanic fields (e.g., San Francisco volcanic field, Arizona; Cima volcanic field, California; Michoácan–Guanajuato volcanic field, Mexico; and Lamongan volcanic field, East Java), the range of morphologies encompasses almost all of those observed worldwide for cinder cones. Three new 40Ar/39Ar age dates are combined with 19 previously published dates for cones in Guatemala and El Salvador. There is no indication that the morphologies of these cones have changed over the last 500–1000 ka. Furthermore, a re-analysis of published data for other volcanic fields suggests that only in the Cima volcanic field (of those studied) is there clear evidence of degradation with age. Preliminary results of a numerical model of cinder cone growth are used to show that the range of morphologies observed in the Guatemalan cinder cones could all be primary, that is, due to processes occurring at the time of eruption.
    Description: Support for Walker was provided by NSF MARGINS grant OCE- 0405666.
    Description: Published
    Description: 39-52
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: open
    Keywords: cinder cones ; morphology ; age dating ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 18
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    Fluid circulation in the upper brittle crust: Thickness distribution, hydraulic transmissivity fluid inclusion and isotopic data of veins hosted in the Oligocene sandstones of the Macigno Formation in southern Tuscany, Italy (2011)
    Elsevier
    Details
    Publication Date: 2020-11-30
    Description: We present structural analysis, fluid inclusion data on calcite and quartz, and isotopic composition of calcite forming veins occurring in the upper crustal level and hosted in Oligocene sandstone in southern Tuscany (Italy). The veins have been analysed in two sites few kilometres apart, along well-exposed coastal cliffs and in an abandoned quarry. These two sites were at a different depths at the time of the vein formation with a Δh ~ 100 m. Structural analysis of veins provided estimations of stress ratio (Φ = (σ2 − σ3)/(σ1 − σ3)), driving stress ratio (R′ = (Pf − σ3)/(σ1 − σ3)) and fluid overpressure (ΔPo = Pf − σ3) at the time of vein formation. The estimated ΔPo is in the range of 42–103 MPa, Φ = 0.24 and R′ = 0.45, indicating that fluid pressure was higher than the intermediate principal stress at the time of veins formation. The veins' thickness (t) shows a clear power-law distribution (D = 1.8835 and R2 = 0.9762) in the lowermost site (coast) and a negative exponential distribution (a = 0.6943 and R2 = 0.9921) in the uppermost site (abandoned quarry). The vein thickness distributions have been used to compute the average transmissivity of the veins in the two sites. The computed transmissivity for the vein formation is ~ 10−4 m2 s−1, with higher values attained by the veins having negative exponential thickness distribution. Fluid inclusions studies highlighted that in both calcite and quartz, water-rich inclusions, with salinities of 2.2–4.3 wt.% NaCl equiv., and methane-rich inclusions were coevally trapped during fluid un-mixing processes. Thermogenic origin, from thermal maturation of organic matter present in the Macigno Formation, is proposed for methane. Whereas, the similarity between the δ18O (from 14.9 to 17.4‰) and δ13C (from −0.4 to −2.4‰) data of representative calcite veins and the isotopic composition (δ18O: 16.1‰, δ13C: −1.0‰) of host-rock carbonate component, indicates that the fluid which formed calcite was in isotopic equilibrium with the carbonates present in the Oligocene sandstones. The calculated pressure–temperature conditions during the formation of these inclusions are prevalently within the 40–145 MPa and 160–260 °C ranges. The highest pressure values approximate the lithostatic pressure (~ 120 MPa) computed from geological data and are coherent with a geothermal gradient ranges of 35–45 °C/km. Whereas, the lower pressure values are comparable with hydrostatic pressure conditions. The pressure range indicated by fluid inclusion data is also comparable with the fluid pressure estimated from structural analysis. The considerable pressure range can be related to pressure cycling between lithostatic and hydrostatic conditions as a consequence of fault-valve actions and rock fracturing with subsequent pressure recover due to self-sealing process.
    Description: Published
    Description: 118-138
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Vein systems ; Fluid type ; Fluid pressure ; Fluid inclusions ; Upper crust ; Tuscany ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 19
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    Magma vesiculation and infrasonic activity at Stromboli open conduit volcano (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Explosive activity at Stromboli is explained in terms of dynamics of large gas bubbles that ascend in the magma conduit and burst at the free surface generating acoustic pressure that propagates as infrasonic signals in the atmosphere. The rate and the amplitude of the infrasonic activity is directly linked to the rate and the overpressure of the bursting gas bubbles and thus reflects the rate at which magma column degasses under non-equilibrium pressure conditions. We investigate the link between explosive degassing and magma vesiculation by comparing the rate of infrasonic activity with the bubble size distributions (BSDs) of scoria clasts collected during several days of explosive activity at Stromboli. BSDs of scoria show a characteristic power law distribution, which reflect a gas bubble concentration mainly controlled by a combined process of bubble nucleation and coalescence. The cumulative distribution of the infrasonic pressure follows two power laws, indicating a clear separation between the frequent, but weak, bursting of small gas bubbles (puffing) and the more energetic explosions of large gas slugs. The exponents of power laws derived for puffing and explosive infrasonic activity show strongly correlated (0.96) changes with time indicating that when the puffing rate is high, the number of energetic explosions is also elevated. This correlation suggests that both puffing and explosive activity are driven by the same magma degassing dynamics. In addition, changes of both infrasonic power law exponents are very well correlated (0.92 with puffing and 0.87 with explosions) with variations of the BSD exponents of the scoria clasts, providing evidence of the strong interplay between scoria vesiculation and magma explosivity. Our analysis indicates that variable magma vesiculation regimes recorded in the scoria correlate with the event number and energy of the explosive activity. We propose that monitoring infrasound on active volcanoes may be an alternative way to look at the vesiculation process in open conduit systems.
    Description: Published
    Description: 274-280
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Strombolian activity ; magma vesiculation ; infrasound ; conduit dynamics ; explosive volcanism ; bubble size distribution ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 20
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    Relations between deformation and upper crustal magma emplacement in laboratory physical models (2011)
    Elsevier
    Details
    Publication Date: 2020-05-28
    Description: This paper presents analogue models for the emplacement of granitic magmas in upper crustal levels with different mechanical layering during shortening, extension and strike–slip deformation. In particular, we investigated how a weak layer embedded in the upper brittle crust can control the level of magma emplacement. The adopted experimental setup was used to examine the control of soft rocks on the movement of magma through a deforming brittle crust. Model results indicate that the occurrence of a weak (soft) layer embedded in brittle (stiff) material has an impact on the level of magma emplacement. The level of emplacement during both extension and shortening was systematically deeper for models with a soft layer than for purely brittle models. During strike–slip deformation the magma pierced the surface in both purely brittle and brittle–ductile models.
    Description: Published
    Description: 139-146
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Mechanical layering of upper crust ; Magma emplacement ; Analogue modelling ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 21
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    40Ar/39Ar geochronology of Holocene basalts; examples from Stromboli, Italy (2011)
    Elsevier
    Details
    Publication Date: 2020-02-24
    Description: Absolute chronologies of active volcanoes and consequently timescales for eruptive behaviour and magma production form a quantitative basis for understanding the risk of volcanoes. Surprisingly, the youngest records in the geological timescale often prove to be the most elusive when it comes to isotopic dating. Absolute Holocene volcanic records almost exclusively rely on 14C ages measured on fossil wood or other forms of biogenic carbon. However, on volcanic flanks, fossil carbon is often not preserved, and of uncertain origin when present in paleosols. Also, low 14C-volcanic CO2 may have mixed with atmospheric and soil 14C-CO2, potentially causing biased ages. Even when reliable data are available, it is important to have independent corroboration of inferred chronologies as can be obtained in principle using the 40K/40Ar decay system. Here we present results of a 40Ar/39Ar dating study of basaltic groundmass in the products from the Pleistocene e Holocene boundary until the beginning of the historic era for the north-northeastern flank of Stromboli, Aeolian Islands, Italy, identifying a short phase of intensified flank effusive activity 7500 500 a ago, and a maximum age of 4000 900 a for the last flank collapse event that might have caused the formation of the Sciara del Fuoco depression. We expect that under optimum conditions 40Ar/39Ar dating of basaltic groundmass samples can be used more widely for dating Holocene volcanic events.
    Description: The mapping of Stromboli was supported by a grant to S. Calvari (Project V2/01, 2005-2007, funded by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and by the Italian Civil Protection). The sample preparation was carried out by Roel van Elsas of the Institute of Earth Sciences, VU. The new instrumentation in the argon laboratory Institute of Earth Sciences, VU (instrument grant for the CO2 laser, AGES extraction line) was supported by grants from the ISES, VU-Energy conservation fund and the Institute of Earth Sciences). This work was partly supported by INGV through a research grant financed by MIUR-FIRB to G.N.
    Description: Published
    Description: 223-232
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: geochronology ; Stromboli geology ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 22
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    Dike emplacement and flank instability at Mount Etna: Constraints from a poro-elastic-model of flank collapse (2011)
    Elsevier B.V.
    Details
    Publication Date: 2017-04-04
    Description: Many volcanic edifices are subject to flank failure, usually produced by a combination of events, rather than any single process. From a dynamic point of view, the cause of collapse can be divided into factors that contribute to an increase in shear stress, and factors that contribute to the reduction in the friction coefficient μ of a potential basal failure plane. We study the potential for flank failure at Mount Etna considering a schematic section of the eastern flank, approximated by a wedge-like block. For such geometry, we perform a (steady state) limit equilibrium analysis: the resolution of the forces parallel to the possible basal failure plane allows us to determine the total force acting on the potentially unstable wedge. An estimate of the relative strength of these forces suggests that, in first approximation, the stability is controlled primarily by the balance between block weight, lithostatic load and magmatic forces. Any other force (sea load, hydrostatic uplift, and the uplift due to mechanical and thermal pore-fluid pressure) may be considered of second order. To study the model sensitivity, we let the inferred slope α of the basal surface failure vary between −10° and 10°, and consider three possible scenarios: no magma loading, magmastatic load, and magmastatic load with magma overpressure. We use error propagation to include in our analysis the uncertainties in the estimates of the mechanics and geometrical parameters controlling the block equilibrium. When there is no magma loading, the ratio between destabilizing and stabilizing forces is usually smaller than the coefficient of friction of the basal failure plane. In the absence of an initiating mechanism, and with the nominal values of the coefficient of friction μ = 0.7 ± 0.1 proposed, the representative wedge will remain stable or continue to move at constant speed. In presence of magmastatic forces, the influence of the lateral restraint decreases. If we consider the magmastatic load only, the block will remain stable (or continue to move at constant speed), unless the transient mechanical and thermal pressurization significantly decrease the friction coefficient, increasing the instability of the flank wedge for α 〉 5° (seaward dipping decollement). When the magma overpressure contribution is included in the equilibrium analysis, the ratio between destabilizing and stabilizing forces is of the same order or larger than the coefficient of friction of the basal failure plane, and the block will become unstable (or accelerate), especially in the case of the reduction in friction coefficient. Finally, our work suggests that the major challenge in studying flank instability at Mount Etna is not the lack of an appropriate physical model, but the limited knowledge of the mechanical and geometrical parameters describing the block equilibrium.
    Description: This work was funded by Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the Italian Dipartimento per la Protezione Civile (DPC) (DPC-INGV project V4 “Flank”).
    Description: Published
    Description: 153-164
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; dike intrusion ; flank instability ; poro-elasticity ; analytical modelling ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
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  • 23
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    The magmatic feeding system of the Campi Flegrei caldera: Architecture and temporal evolution (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: To develop a model of both the structure and evolution of the Campi Flegrei caldera (CFc) magmatic feeding system, geochronological, geochemical and Sr, Nd, Pb and B isotopic data of representative volcanic products of the past 15 ka have been combined with geophysical and melt inclusion literature data, structural setting and dynamics of the resurgent caldera. According to previous petrological data, the CFc magmatic feeding system consists of a deep reservoir, in which mantle-derived K-basaltic parental magmas differentiate to shoshonite, latite and trachyte, through combined crustal contamination and fractional crystallization processes, and shallowreservoirswhere the evolvedmagmas further differentiate andmingle/mix before eruptions. The Sr,Nd, Pb, and B isotope data allowrecognition of three distinctmagmatic components.One component is believedto be residualmagmafromtheNeapolitanYellowTuff (NYT) caldera forming eruption. The NYT component (87Sr/86Sr of 0.70750–53, 143Nd/144Nd ratio of ca. 0.51246, 206Pb/204Pb of ca. 19.04 and δ11B of ca. –7.9‰), has been the most prevalent component over the past 15 ka being mixed, in most cases, with the other two components. One of these other components is best recognized in the Minopoli 2 magma, first erupted 10 ka ago. Minopoli 2 magma is shoshonitic in composition and is the most enriched in radiogenic Sr (87Sr/86Sr of ca. 0.70860) and unradiogenic Nd and Pb (143Nd/144Nd ratio of ca. 0.51236, 206Pb/204Pb of ca. 18.90), and is characterised by δ11B value of ca. –7.32‰. The third component is trachytic in composition and has higher 206Pb/204Pb (ca. 19.08), lower 87Sr/86Sr (ca. 0.70726) and δ11B (−9.8‰) and higher 143Nd/144Nd (ca. 0.51250), with respect to the NYT component. This third component is best recognized in the Astroni 6 magma and did not appear until ca. 4 ka. The identified isotopically distinct magmatic components were erupted in different sectors of the CFc. During both I (b14.9–9.5 ka) and II (8.6–8.2 ka) epochs of volcanic activity,magmas similar to the NYT component, and those resulting from mixing between Minopoli 2 and NYT components were erupted from vents located mostly on the marginal faults of the NYT caldera. During the III epoch (4.8–3.8 ka) magmas either similar to NYT, or resulting from mixing between Astroni 6 and NYT components were erupted from vents located along faults bordering the La Starza resurgent block and, subordinately, the NYT caldera. Moreover, magmas resulting from mixing betweenMinopoli 2 and NYT components were erupted fromvents located along NE–SW regional faults activated during caldera resurgence. The inferred present structure of the feeding system is characterised by a deep reservoir, whose top is at about 8 kmdepth, that hosts shoshonitic–trachyticmagmas. Remnants of the NYT magma reside at shallower depth in different sectors of the crust underlying CFc, and were sometimes intercepted by volatile-rich magmas of deep provenance during the three epochs of CFc volcanic activity.
    Description: Published
    Description: 227-241
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei caldera ; Magmatic system ; Caldera structure ; Geochemistry ; Isotopes ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 24
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    The Miocene Costa Giardini diatreme, Iblean Mountains, southern Italy: Model for maar-diatreme formation on a submerged carbonate platform (2011)
    Elsevier
    Details
    Publication Date: 2020-02-24
    Description: In this paper we present a model for the growth of a maar-diatreme complex in a shallow marine environment. The Miocene-age Costa Giardini diatreme near Sortino, in the region of the Iblei Mountains of southern Sicily, has an outer tuff ring formed by the accumulation of debris flows and surge deposits during hydromagmatic eruptions. Vesicular lava clasts, accretionary lapilli and bombs in the older ejecta indicate that initial eruptions were of gas-rich magma. Abundant xenoliths in the upper, late-deposited beds of the ring suggest rapid magma ascent, and deepening of the eruptive vent is shown by the change in slope of the country rock. The interior of the diatreme contains nonbedded breccia composed of both volcanic and country rock clasts of variable size and amount. The occurrence of bedded hyaloclastite breccia in an isolated outcrop in the middle-lower part of the diatreme suggests subaqueous effusion at a low rate following the end of explosive activity. Intrusions of nonvesicular magma, forming plugs and dikes, occur on the western side of the diatreme, and at the margins, close to the contact between breccia deposits and country rock; they indicate involvement of volatile-poor magma, possibly during late stages of activity. We propose that initial hydromagmatic explosive activity occurred in a shallow marine environment and the ejecta created a rampart that isolated for a short time the inner crater from the surrounding marine environment. This allowed explosive activity to draw down the water table in the vicinity of the vent and caused deepening of the explosive center. A subsequent decrease in the effusion rate and cessation of explosive eruptions allowed the crater to refill with water, at which time the hyaloclastite was deposited. Emplacement of dikes and plugs occurred nonexplosively while the breccia sediment was mostly still soft and unconsolidated, locally forming peperites. The sheltered, low-energy lagoon filled with marine limestones mixed with volcaniclastic material eroded from the surrounding ramparts. Ultimately, lagoonal sediments accumulated in the crater until subsidence or erosion of the tuff ring caused a return to normal shallow marine conditions.
    Description: LT thanks the Faculty Research Committee of Le Moyne College for providing travel funds that made this collaboration possible.
    Description: Published
    Description: 557–576
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: restricted
    Keywords: Iblean Mountains ; explosive eruptions ; diatremes ; shallow water environment ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
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    A microscopic information system (MIS) for petrographic analysis (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The database and visualization facilities of Geographic Information System (GIS) software are employed to support the analysis of rock texture from thin section by image processing. A Microscopic Information System (MIS) is hence obtained. The method is applied to transmitted light images of 137 samples obtained from 8 granitoid rocks. A slide scanner and a mount for crossed polarization are used to acquire the input images. For each thin section 5 collimated RGB images are scanned: 4 under different directions of crossed polarization and 1 without polarization. A grain segmentation procedure, based on two region growing functions is applied. The output is converted to vector format and refined using editing tools in the MIS environment, which enables a straightforward match between the input imagery and the final vectorized texture. GIS software provides optimal management of the MIS database, allowing the cumulative measurement of more than 87,000 grains.
    Description: Published
    Description: 665-674
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 5.3. TTC - Banche dati vulcanologiche
    Description: JCR Journal
    Description: reserved
    Keywords: Granitoid rocks ; Geographic Information System (GIS) ; Image processing ; Petrography ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques
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  • 26
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    Late Miocene submarine volcanism in ANDRILL AND-1B drill core, Ross Embayment, Antarctica (2011)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: The ANDRILL McMurdo Ice Shelf initiative recovered a 1285-m-long core (AND-1B) composed of cyclic glacimarine sediments with interbedded volcanic deposits. The thickest continuous volcanic sequence by far is ∼175 m long and is found at mid-core depths from 584.19 to 759.32 m below seafloor. The sequence was logged, and initial interpretations of lithostratigraphic subdivisions were made on ice during drilling in late 2006. Subsequent observations, based on image, petrographic, and scanning electron microscopy–energy dispersive spectroscopy analyses, provide a more detailed, revised interpretation of a thick submarine to emergent volcanic succession. The sequence is subdivided into two main subsequences on the basis of sediment composition, texture, and alteration style. The ∼70-m-thick lower subsequence consists mostly of monothematic stacked volcanic-rich mudstone and sandstone deposits, which are attributed to epiclastic gravity flow turbidite processes. This subsequence is consistent with abundant active volcanism that occurred at a distal site with respect to the drill site. The ∼105-m-thick upper subsequence consists mainly of interbedded tuff, lapilli tuff, and volcanic diamictite. A Late Miocene (6.48 Ma) 2.81-m-thick subaqueously emplaced lava flow occurs within the second subsequence. This second subsequence is attributed to recurring cycles of submarine to emergent volcanic activity that occurred proximal to the drill site. This new data set provides (1) the first rock evidence of significant Late Miocene submarine volcanic activity in the Ross Embayment during a period of no to limited glaciation, and (2) a rich stratigraphic record that elucidates submarine volcano-sedimentary processes in an offshore setting.
    Description: Published
    Description: 524-536
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: reserved
    Keywords: Antarctica ; Andrill ; Ice-Volcano interactions ; Submarine Volcanism ; Volcanoclastic rocks ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 27
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    The pre-eruptive volatile contents of recent basaltic and pantelleritic magmas at Pantelleria (Italy) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Pantelleria Island, located in the Sicily Channel Rift Zone (Italy), is the type locality for the peralkaline rhyolitic rocks called pantellerites. In the last 50 ka, after the large Green Tuff caldera-forming eruption, volcanic activity at Pantelleria has consisted of effusive and explosive eruptions mostly vented inside and along the rim of the caldera and producing silicic lava flows, lava domes and poorly dispersed pantelleritic pumice fall deposits. Basaltic cinder cones and lava flows are only present outside the caldera in the NW sector of the island. The most recent basaltic (Cuddie Rosse, 20 ka) and pantelleritic (Cuddia Randazzo and Cuddia del Gallo, 6 ka) pyroclastic products were sampled to investigate magmatic volatile contents through the study of melt inclusions. The melt inclusions in pyroxene and olivine phenocrysts of Cuddie Rosse scoriae have an alkali basalt composition. The dissolved volatiles comprise 0.9–1.6 wt.% H2O, several hundred ppm of CO2, 1600–2000 ppm of sulphur and 500–900 ppm of chlorine. The water–carbon dioxide couple gives a confining pressure 2 kbar prior to the eruption. This result indicates that episodes of magma ponding and crystallization occurred in the upper crust prior to eruption. The melt inclusions in feldspar, fayalite and aenigmatite phenocrysts of Cuddia del Gallo and Cuddia Randazzo pumice have a pantelleritic composition (Agpaitic Indices 1.3–2.1), up to 4.4 wt.% H2O, 8700 ppm Cl, 6000 ppm F, and CO2 below the detection limit. Sulphur averaging 420 ppm has been measured in Cuddia Randazzo melt inclusions. These data indicate relatively high volatile contents for these low-energy Strombolian-type eruptions. Melt inclusions in Cuddia del Gallo pumice show the most evolved composition (Agpaitic Indices 2–2.1) and the highest volatile content, in agreement with fluid saturation conditions in the magma chamber prior to the eruption. This implies a confining pressure of 1 kbar for the top of the pantelleritic reservoir. The composition of melt inclusions and mineralogical assemblage of Cuddia Randazzo pumice indicate that it has a lower evolutionary degree (Agpaitic Indices 1.3–1.8) and lower pre-eruptive Cl and H2O contents than Cuddia del Gallo pumice. An increase in pressure due to the exsolution of volatiles in the upper part of the pantelleritic reservoir may have triggered the Cuddia del Gallo explosive eruption. Evidence of widespread pre-eruptive mingling between trachytes and pantellerites suggests that the intrusion of trachytic magma into the pantelleritic reservoir likely played a major role in destabilizing the magma system just prior to the Cuddia Randazzo event.
    Description: Published
    Description: 191-201
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Pantelleria ; peralkaline ; volatiles ; melt inclusions ; eruptive style ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 28
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    Influence of thermal and mechanical cracks on permeability and elastic wave velocities in a basalt from Mt. Etna volcano subjected to elevated pressure (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We report simultaneous laboratory measurements of seismic velocities and fluid permeability on lava flow basalt from Etna (Italy). Results were obtained for dry and saturated samples deformed under triaxial compression. During each test, the effective pressure was first increased up to 190 MPa to investigate the effect of pre-existing crack closure on seismic properties. Then, the effective pressure was unloaded down to 20 MPa, a pressure which mirrors the stress field acting under a lava pile of approximately 1.5–2 km thick, and deviatoric stress was increased until failure of the specimens. Using an effective medium model, the measured elastic wave velocities were inverted in terms of two crack densities: ρi the crack density of the pre-existing thermal cracks and ρv the crack density of the stress-induced cracks. In addition a link was established between elastic properties (elastic wave velocities Vp and Vs) and permeability using a statistical permeability model. Our results show that the velocities increase with increasing hydrostatic pressure up to 190 MPa, due to the closure of the pre-existing thermal cracks. This is interpreted by a decrease of the crack density ρi from ~1 to 0.2. The effect of pre-existing cracks closure is also highlighted by the permeability evolution which decreases of more than two orders of magnitude. Under deviatoric loading, the velocities signature is interpreted, in the first stage of the loading, by the closure of the pre-existing thermal cracks. However, with increasing deviatoric loading newly-formed vertical cracks nucleate and propagate. This is clearly seen from the velocity signature and its interpretation in term of crack density, the location of the acoustic emission sources, and from microstructural observations. This competition between pre-existing cracks closure and propagation of vertical cracks is also seen from the permeability evolution, and our study shows that mechanically-induced cracks has lesser influence on permeability change than pre-existing thermal cracks.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: open
    Keywords: Elastic wave velocity, Permeability, Acoustic emission, Fracture, Basalt ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 29
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    Spatio-temporal evolution of volcano seismicity: A laboratory study (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We report a laboratory and microstructural study of a suite of deformation experiments in which basalt from Mount Etna volcano is deformed and fractured at an effective confining pressure representative of conditions under a volcanic edifice (40 MPa). Particular attention was paid to the formation of a fracture and damage zone with which to stimulate coupled hydro-mechanical interactions that create the various types of seismicity recorded on volcanic edifices, and which usually precede eruption. Location of AE events through time shows the formation of a fault plane during which waveforms exhibit the typical high frequency characteristics of volcano-tectonic (VT) earthquakes. We found that these VT earthquakes were particularly pronounced when generated using dry samples, compared to samples saturated with a pore fluid (water). VT events generated during deformation of water saturated sample are characterised by a distinctive high frequency onset and a longer, low frequency coda exhibiting properties often seen in the field as hybrid events. We present evidence that hybrid events are, in fact, the common type of volcanic seismic event with either VT or low frequency (LF) events representing end members, and whose proportion depend on pore fluid being present in the rock type being deformed, as well as how close the rock is to failure. We find a notable trend of reducing instances of hybrid events leading up to the failure stage in our experiments, suggesting that during this stage, the pore fluid present in the rock moves sufficiently quickly to provide a resonance, seen as a LF coda. Our data supports recent modeling and field studies that postulate that hybrid events generated in volcanic areas are likely to be generated through the interaction of hydrothermal fluids moving through a combination of pre-existing microcrack networks and larger faults, such as those we observe in forensic (post-test) examination.
    Description: Published
    Description: 315-323
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: volcano-tectonics, acoustic emission, rock physics, seismology, hazard ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
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  • 30
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    The feeding system of Agnano–Monte Spina eruption (Campi Flegrei, Italy): Dragging the past into present activity and future scenarios (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Magmatic processes triggering eruptions at Campi Flegrei caldera (southern Italy) and their relationships with the widespread emissions of fluids and caldera unrest episodes, are poorly constrained. The 4.1 ka B.P. Agnano–Monte Spina eruption, the reference event for a future large-size explosive eruption at Campi Flegrei, was investigated to shed light, through melt inclusion and isotope analyses, on the geochemical processes operating in the plumbing system. Chemical and isotopic data on whole rocks and glasses suggest that at least two magma batches mixed during the course of the eruption. Melt inclusion data highlight the pre-eruption storage conditions of two magmatic end-members. One end-member is like the less differentiated (shoshonitic) Campi Flegrei erupted magma, while the other could be a residual of the Neapolitan Yellow Tuff magma. Mixing between these two components was driven by a large gas phase which sustained the ascent of magmas of deep provenance. The H2O and CO2 contents in pyroxene-hosted melt inclusions yield entrapment pressures between 107 and 211 MPa, corresponding to depths between 4 and 8 km. The degassing trends reveal two extreme patterns. One pattern, already documented in the literature, is the volatile signature of poorly differentiated magmas ascending from more than 8 km depth, while the other is related to a gas-dominated magma, flushed by a CO2-rich gas phase partly released from the deep reservoir. This study provides a conceptual frame for unrest phases at Campi Flegrei, such as the 1982–84 event. Uplift phases can be related to closed-system ascent of magmas and fluids from more than 8 km depth, and their emplacement at shallow levels. This leads the shallow system to store, and then progressively release, the accumulated gas. In this view, both unrest episodes and eruptions could be strongly influenced by both the achievement of a critical upper limit of gas storage in the shallow magmatic reservoir and the stress and fracturing state of the roof rocks. The present results help to constrain the preeruptive conditions expected at Campi Flegrei caldera in case of a future large-size eruptive event.
    Description: Published
    Description: 135–147
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Sr and Nd isotopes ; Melt inclusions ; Gas flushing ; Magma mixing ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 31
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    The regular shape of stratovolcanoes: A DEM-based morphometrical approach (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We studied the shape of the most regular-shaped stratovolcanoes of the world to mathematically define the form of the ideal stratovolcano. Based on the Shuttle Radar Topographic Mission data we selected 19 of the most circular and symmetrical volcanoes, which incidentally all belong to subduction-related arcs surrounding the Pacific. The selection of volcanoes benefitted from the introduction of a new definition of circularity which is more robust than previous definitions, being independent of the erosional dissection of the cone. Our study on the shape of stratovolcanoes was based on the analysis of the radial elevation profiles of each volcano. The lower half section of the volcanoes is always well fitted by a logarithmic curve, while the upper half section is not, and falls into two groups: it is fitted either by a line (“C-type”, conical upper part) or by a parabolic arc (“P-type”, parabolic/concave upper part). A quantitative discrimination between these groups is obtained by fitting their upper slope with a linear function: C-type volcanoes show small, whereas P-type volcanoes show significant negative angular coefficient. The proposed threshold between the two groups is − 50 × 10− 4°/m. Chemical composition of eruptive products indicates higher SiO2 and/or higher H2O content for C-type volcanoes, which could imply a higher incidence of mildly explosive (e.g. strombolian) eruptions. We propose that this higher explosivity is responsible for forming the constant uppermost slopes by the deposition of ballistic tephra and its subsequent stabilisation at a constant angle. By contrast, P-type volcanoes are characterized by a smaller SiO2 and H2O content, which can be responsible for a higher incidence of effusive events and/or a lower incidence of upper flank-forming (i.e. mild) explosive eruptions. Therefore, the concave upper flanks of these volcanoes may be shaped typically by lava flows. Based on this hypothesis, we propose that the morphometric analysis of the elevation profile of stratovolcanoes can provide insights into their dominant eruptive style.
    Description: Published
    Description: 171-181
    Description: 1.10. TTC - Telerilevamento
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: stratovolcano ; SRTM ; shape analysis ; elevation profile ; circularity ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 32
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    Monogenetic vent self-similar clustering in extending continental crust: Examples from the East African Rift System (2011)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: The spatial clustering of fracture networks and vents in basaltic volcanic fields has been analyzed in three sectors of the East African Rift System, the classical example of an active continental rift. Fracture trace maps and monogenetic basaltic vents have been thus collected in the Afar Depression, in the Main Ethiopian Rift, and in the Virunga Belt (Western Rift). The mapped vents are generally younger than 2 Ma, and most are of Holocene age. All the analyzed fracture networks have self-similar clustering with fractal exponents (Df) varying in the 1.54−1.85 range. Also, vents show a self-similar clustering with fractal exponents (Dv) in the 1.17−1.50 range. For all the studied sectors, the relationship Df 〉 Dv has been observed. The fractal exponents for vents (Dv) of power-law distributions are computed in a range of lengths with a lower and an upper cutoff. The upper cutoff (Uco) for the fractal clustering of vents in the studied sectors of the East African Rift System are compared with the respective crust thickness derived by independent geophysical data. The computed Ucos for the studied sectors well match the crust thickness in the volcanic fields. A preliminary conceptual model to explain the relationships between the upper cutoffs of the fractal distribution of vents and the thickness of the crust in the volcanic fields is thus proposed in the light of the percolation theory.
    Description: Published
    Description: 1.10. TTC - Telerilevamento
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: crustal thickness ; basaltic volcanic fields ; vent distribution ; EASR ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 33
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    Introduction: LASI III—Magma pulses and sheets in tabular intrusions (2011)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: The origins of granites and intrusive rocks have been widely discussed for a couple of centuries, and the way volcanoes work and their magma forms have attracted scientists, naturalists, and laymen since the dawn of humankind. However, shallow igneous intrusions, representing the obvious link between the hidden kingdom of Pluto and the fiery realm of Vulcanus, have been partly overlooked, leading to some lack of communication between “plutonic” and “volcanic” researchers. An effort devoted to heal this breach has been contributed to by the establishment of the LASI conferences (named after laccolith and sill, the main types of shallow igneous intrusions).
    Description: Published
    Description: 161-162
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: upper crustal level intrusions ; emplacement of magma ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 34
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    Late Quaternary deformation on the island of Pantelleria: New constraints for the recent tectonic evolution of the Sicily Channel Rift (southern Italy). (2010)
    Elsevier
    Details
    Publication Date: 2020-12-15
    Description: Structural observations carried out on the volcanic Island of Pantelleria show that the tectonic setting is dominated by NNE trending normal faults and by NW-striking right-lateral strike-slip faults with normal component of motion controlled by a ≈N 100°E oriented extension. This mode of deformation also controls the development of the eruptive fissures, dykes and eruptive centres along NNE–SSW belts that may thus represent the surface response to crustal cracking with associated magma intrusions. Magmatic intrusions are also responsible for the impressive vertical deformations that affect during the Late Quaternary the south-eastern segment of the island and producing a large dome within the Pantelleria caldera complex. The results of the structural analysis carried out on the Island of Pantelleria also improves the general knowledge on the Late Quaternary tectonics of the entire Sicily Channel. ESE–WNW directed extension, responsible for both the tectonic and volcano-tectonic features of the Pantelleria Island, also characterizes, at a greater scale, the entire channel as shown by available geodetic and seismological data. This mode of extension reactivates the older NW–SE trending fault segments bounding the tectonic troughs of the Channel as right-lateral strike-slip faults and produces new NNE trending pure extensional features (normal faulting and cracking) that preferentially develop at the tip of the major strike-slip fault zones. We thus relate the Late Quaternary volcanism of the Pelagian Block magmatism to dilatational strain on the NNE-striking extensional features that develop on the pre-existing stretched area and propagate throughout the entire continental crust linking the already up-welled mantle with the surface.
    Description: Published
    Description: 75-82
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Extensional tectonics ; Quaternary ; Volcanism ; Pantelleria Island ; Southern Italy ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
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  • 35
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    Understanding stress and deformation in active volcanoes (2010)
    Elsevier
    Details
    Publication Date: 2021-06-15
    Description: No eruption, no caldera collapse, and no landslide can take place in a volcano unless its state of stress is suitable for the associated type of rock failure. The state of stress, in turn, results in deformation, and both stress and deformation depend on the mechanical properties of the rocks that constitute the volcano. Understanding stress and deformation in volcanoes is thus of fundamental importance for understanding unrest periods and for accurate forecasting volcano failure, such as may result in large-scale lateral and vertical collapses and eruptions.
    Description: Published
    Description: 1-3
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: stress, deformation, volcano tectonics, physical propertie of volcanic rocks ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 36
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    Shifting styles of basaltic explosive activity during the 2002-03 eruption of Mt. Etna, Italy (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The 2002–03 flank eruption of Etna was characterized by two months of explosive activity that produced copious ash fallout, constituting a major source of hazard and damage over all eastern Sicily. Most of the tephra were erupted from vents at 2750 and 2800 m elevation on the S flank of the volcano, where different eruptive styles alternated. The dominant style of explosive activity consisted of discrete to pulsing magma jets mounted by wide ash plumes, which we refer to as ash-rich jets and plumes. Similarly, ash-rich explosive activity was also briefly observed during the 2001 flank eruption of Etna, but is otherwise fairly uncommon in the recent history of Etna. Here, we describe the features of the 2002–03 explosive activity and compare it with the 2001 eruption in order to characterize ash-rich jets and plumes and their transition with other eruptive styles, including Strombolian and ash explosions, mainly through chemical, componentry and morphology investigations of erupted ash. Past models explain the transition between different styles of basaltic explosive activity only in terms of flow conditions of gas and liquid. Our findings suggest that the abundant presence of a solid phase (microlites) may also control vent degassing and consequent magma fragmentation and eruptive style. In fact, in contrast with the Strombolian or Hawaiian microlite-poor, fluidal, sideromelane clasts, ash-rich jets and plumes produce crystal-rich tachylite clasts with evidence of brittle fragmentation, suggesting that high groundmass crystallinity of the very top part of the magma column may reduce bubble movement while increasing fragmentation efficiency.
    Description: Published
    Description: 110-122
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; basaltic explosive activity ; ash-rich jet and plume ; tachylite ; sideromelane ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
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    Insights into fluid circulation across the Pernicana Fault (Mt. Etna, Italy) and implications for flank instability (2010)
    Elsevier B.V.
    Details
    Publication Date: 2017-04-04
    Description: We conducted geophysical–geochemical measurements on a ∼2 kmN–S profile cutting across the Pernicana Fault, one of the most active tectonic features on the NE flank of Mt. Etna. The profile passes from the unstable E flank of the volcano (to the south) to the stable N flank and significant fluctuations in electrical resistivity, self-potential, and soil gas emissions (CO2, Rn and Th) are found. The detailed multidisciplinary analysis reveals a complex interplay between the structural setting, uprising hydrothermal fluids, meteoric fluids percolating downwards, ground permeability, and surface topography. In particular, the recovered fluid circulation model highlights that the southern sector is heavily fractured and faulted, allowing the formation of convective hydrothermal cells. Although the existence of a hydrothermal system in a volcanic area does not surprise, these results have great implications in terms of flank dynamics at Mt. Etna. Indeed, the hydrothermal activity, interacting with the Pernicana Fault activity, could enhance the flank instability. Our approach should be further extended along the full extent of the boundary between the stable and unstable sectors of Etna for a better evaluation of the geohazard in this active tectonic area.
    Description: This work was partly financed by the DPC-INGV FLANK and LAVA Projects.
    Description: Published
    Description: 137–142
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Pernicana Fault ; fluid circulation ; structural geology ; Etna ; magnetic ; electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 38
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    Large mafic eruptions at Alban Hills Volcanic District (Central Italy): Chronostratigraphy, petrography and eruptive behavior (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Despite its ultra-potassic, basic geochemistry (40≤SiO2≤50 wt.%), the Alban Hills Volcanic District was characterized by a highly explosive phase of activity, the Tuscolano–Artemisio phase, which emplaced very large volumes (several tens of km3 each cycle) of pyroclastic-flow deposits, mafic in composition (SiO2≤45 wt.%) in the time span 600–350 ka. In contrast to the abundance of pyroclastic-flow deposits, very scarce basal Plinian deposits and, more in general, fallout deposits are associated to these products. While some of the pyroclastic-flow deposits have been described in previous literature, no specific work on the Tuscolano–Artemisio phase of activity has been published so far. In particular, very little is known on the products of the early stages, as well as of the final, post-caldera activity of each eruptive cycle. Here we present a comprehensive stratigraphic and geochronologic study of the Tuscolano–Artemisio phase of activity, along with new textural and petrographic data. We describe the detailed stratigraphy and petrography of five reference sections, where the most complete suites of products of the eruptive cycles, comprising the initial through the final stages, are exposed.We assess the geochronology of these sections by means of 18 new 40Ar/39Ar age determinations, integrating them with 16 previously performed, aimed to describe the eruptive behavior of the Alban Hills Volcanic District during this phase of activity, and to assess the recurrence time and the duration of the dormancies. The overall explosive activity appears to be strictly clustered in five eruptive cycles, fairly regularly spaced in time and separated by very long dormancies, in the order of several ten of kyr, during which no volumetrically appreciable eruption occurred, as the lack of deposits dated to this time-interval testify.We propose a volcanotectonic model that explains this peculiar eruptive behavior, unparalleled in the other coeval volcanic districts of the Tyrrhenian margin of Italy, as related to the local transpressive tectonic regime.
    Description: Published
    Description: 217-232
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Alban Hills 40Ar/39Ar geochronology explosive eruptions K-alkaline magmas pyroclastic-flow deposits volcanotectonics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
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    The role of syn-eruptive vesiculation on explosive basaltic activity at Mt. Etna, Italy (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We investigated the dynamics of explosive activity at Mt. Etna between 31 August and 15 December 2006 by combining vesicle studies in the erupted products with measurements of the gas composition at the active, summit crater. The analysed scoria clasts present large, connected vesicles with complex shapes and smaller, isolated, spherical vesicles, the content of which increases in scoriae from the most explosive events. Gas geochemistry reports CO2/SO2 and SO2/HCl ratios supporting a deep-derived gas phase for fire-fountain activity. By integrating results from scoria vesiculation and gas analysis we find that the highest energy episodes of Mt. Etna activity in 2006 were driven by a previously accumulated CO2-rich gas phase but we highlight the lesser role of syn-eruptive vesicle nucleation driven by water exsolution during ascent. We conclude that syn-eruptive vesiculation is a common process in Etnean magmas that may promote a deeper conduit magma fragmentation and increase ash formation.
    Description: Published
    Description: 265-269
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; fire-fountains ; vesicle textures ; volcanic degassing ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 40
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    A Microscopic Information System (MIS) for petrographic analysis (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The database and visualization facilities of Geographic Information System (GIS) software are employed to support the analysis of rock texture from thin section by image processing. A Microscopic Information System (MIS) is hence obtained. The method is applied to transmitted light images of 137 samples obtained from 8 granitoid rocks. A slide scanner and a mount for crossed polarization are used to acquire the input images. For each thin section 5 collimated RGB images are scanned: 4 under different directions of crossed polarization and 1 without polarization. A grain segmentation procedure, based on two region growing functions is applied. The output is converted to vector format and refined using editing tools in the MIS environment, which enables a straightforward match between the input imagery and the final vectorized texture. GIS software provides optimal management of the MIS database, allowing the cumulative measurement of more than 87 000 grains.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 5.3. TTC - Banche dati vulcanologiche
    Description: JCR Journal
    Description: open
    Keywords: Granitoid rocks ; Geographic Information System ; Image processing ; Petrography ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques
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  • 41
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    Late Miocene Submarine Volcanism in the Ross Embayment, Antarctica (2010)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: Abstract: The ANDRILL McMurdo Ice Shelf (MIS) initiative recovered a 1285 m-long core (MIS AND-1B) composed of cyclic glacimarine sediments with interbedded volcanic deposits. By far the thickest continuous volcanic sequence is about 175 m long and is found at midcore depths from 584.19 to 759.32 meters below sea floor (mbsf). The sequence was logged and initial interpretations of lithostratigraphic subdivisions were made on-ice during drilling in late 2006. Subsequent observations, based on image, petrographic, and SEM-EDS analyses, provide a more detailed, revised interpretation of a thick submarine to emergent volcanic succession. The sequence is subdivided into two main subsequences on the basis of sediment composition, texture and alteration style. The ~70 m thick lower subsequence consists mostly of monothematic stacked volcanic-rich mudstone and sandstone deposits, which are attributed to epiclastic gravity flow turbidite processes. This subsequence is consistent with abundant active volcanism that occurred at a distal site with respect to the drill site. The ~105 m thick upper subsequence consists mainly of interbedded tuff, lapilli tuff, and volcanic diamictite. A late Miocene (6.48 Ma) 2.81 m-thick subaqueously emplaced lava flow occurs within the second subsequence. This second subsequence is attributed to recurring cycles of submarine to emergent volcanic activity that occurred proximal to the drill site. This new dataset provides 1) the first rock evidence of significant late Miocene submarine volcanic activity in the Ross Embayment during a period of no to limited glaciation , and 2) a rich stratigraphic record that elucidates submarine volcano-sedimentary processes in an off-shore setting.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: open
    Keywords: ANDRILL ; AND1-B core ; McMurdo Sound ; submarine volcanism ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 42
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    Quantitative analysis of extensional joints in the southern Adriatic foreland (Italy), and the active tectonics of the Apulia region (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Adriatic foreland of the Apennines comes ashore only in Apulia (easternmost Italy). Its southern part, our study area, lacks any structural analysis devoted to define its recent-to-active tectonics. Throughout the Quaternary, this region was affected by mild brittle deformation with rare faults, characterized by small displacement, and widespread extension joints, frequently organized in sets. Therefore, we conducted a quantitative and systematic analysis of the joint sets affecting Quaternary deposits, by applying an inversion technique ad hoc to infer the orientation and ratio of the principal stress axes, R = (σ2 - σ3)/(σ1 - σ3). Within a general extensional regime, we recognized three deformational events of regional significance. The oldest event, constrained to the early and middle part of the Middle Pleistocene, is characterized by variable direction of extension and R between 0.64-0.99. The penultimate event, dated late Middle Pleistocene, is characterized by an almost uniaxial tension, with a horizontal σ3 striking ~N43°E; R is high, between 0.85-0.99. The most recent event is characterized by the lowermost R values, that never exceed 0.47 and are frequently 〈0.30, indicating a sort of horizontal „radial‟ extension. This event is not older than the Late Pleistocene and possibly reflects the active stress field still dominating the entire study area.
    Description: In press
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Quaternary tectonics ; brittle deformation ; fracture ; Pleistocene ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 43
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    Dike emplacement and flank instability at Mount Etna: Constraints from a poro-elastic-model of flank collapse (2010)
    Elsevier B.V.
    Details
    Publication Date: 2017-04-04
    Description: Many volcanic edifices are subject to flank failure, usually produced by a combination of events, rather than any single process. From a dynamic point of view, the cause of collapse can be divided into factors that contribute to an increase in shear stress, and factors that contribute to the reduction in the friction coefficient μ of a potential basal failure plane. We study the potential for flank failure at Mount Etna considering a schematic section of the eastern flank, approximated by a wedge-like block. For such geometry, we perform a (steady state) limit equilibrium analysis: the resolution of the forces parallel to the possible basal failure plane allows us to determine the total force acting on the potentially unstable wedge. An estimate of the relative strength of these forces suggests that, in first approximation, the stability is controlled primarily by the balance between block weight, lithostatic load and magmatic forces. Any other force (sea load, hydrostatic uplift, and the uplift due to mechanical and thermal pore-fluid pressure) may be considered of second order. To study the model sensitivity, we let the inferred slope α of the basal surface failure vary between −10° and 10°, and consider three possible scenarios: no magma loading, magmastatic load, and magmastatic load with magma overpressure. We use error propagation to include in our analysis the uncertainties in the estimates of the mechanics and geometrical parameters controlling the block equilibrium. When there is no magma loading, the ratio between destabilizing and stabilizing forces is usually smaller than the coefficient of friction of the basal failure plane. In the absence of an initiating mechanism, and with the nominal values of the coefficient of friction μ=0.7±0.1 proposed, the representative wedge will remain stable or continue to move at constant speed. In presence of magmastatic forces, the influence of the lateral restraint decreases. If we consider the magmastatic load only, the block will remain stable (or continue to move at constant speed), unless the transient mechanical and thermal pressurization significantly decrease the friction coefficient, increasing the instability of the flank wedge for αN5° (seaward dipping decollement). When the magma overpressure contribution is included in the equilibrium analysis, the ratio between destabilizing and stabilizing forces is of the same order or larger than the coefficient of friction of the basal failure plane, and the block will become unstable (or accelerate), especially in the case of the reduction in friction coefficient. Finally, our work suggests that the major challenge in studying flank instability at Mount Etna is not the lack of an appropriate physical model, but the limited knowledge of the mechanical and geometrical parameters describing the block equilibrium.
    Description: This work was funded by Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the Italian Dipartimento per la Protezione Civile (DPC) (DPC-INGV project V4 “Flank”).
    Description: In press
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; dike intrusion ; flank instability ; poro-elasticity ; analytical modelling ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
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  • 44
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    The growth and erosion of cinder cones in Guatemala and El Salvador: Models and statistics (2010)
    Elsevier B.V.
    Details
    Publication Date: 2017-04-04
    Description: Morphologic data for 147 cinder cones in southernGuatemala andwestern El Salvador are comparedwith data from 21 the San Francisco volcanic field, Arizona (USA), Cima volcanic field, California (USA), Michoácan–Guanajuato 22 volcanic field, Mexico, and the Lamongan volcanic field, East Java. The Guatemala cones have an average height of 23 110+/−50m, an average basal diameter of 660+/−230m and an average top diameter of 180+/−150m. The 24 generalmorphology of these cones can be described by their average cone angle of slope (24+/−7), average height- 25 to-radius ratio (0.33+/−0.09) and their flatness (0.24+/−0.18). Although the mean values for the Guatemalan 26 cones are similar to those for other volcanic fields (e.g., San Francisco volcanic field, Arizona; Cima volcanic field, 27 California; Michoácan–Guanajuato volcanic field, Mexico; and Lamongan volcanic field, East Java), the range of 28 morphologies encompasses almost all of those observed worldwide for cinder cones. 29 Three new 40Ar/39Ar age dates are combined with 19 previously published dates for cones in Guatemala and El 30 Salvador. There is no indication that the morphologies of these cones have changed over the last 500–1000 ka. 31 Furthermore, a re-analysis of published data for other volcanic fields suggests that only in the Cima volcanic field (of 32 those studied) is there clear evidence of degradation with age. 33 Preliminary results of a numerical model of cinder cone growth are used to show that the range of morphologies 34 observed in the Guatemalan cinder cones could all be primary, that is, due to processes occurring at the time of 35 eruption.
    Description: Support for Walker was provided by NSF MARGINS grant OCE-0405666.
    Description: In press
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: cinder cones ; morphology ; age dating ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 45
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    Revised slip rates for the Alpine fault at Inchbonnie: Implications for plate boundary kinematics of South Island, New Zealand (2010)
    Geological Society of America
    Details
    Publication Date: 2017-04-04
    Description: The northeast-striking, dextral-reverse Alpine fault transitions into the Marlborough Fault System near Inchbonnie in the central South Island, New Zealand. New slip-rate estimates for the Alpine fault are presented following a reassessment of the geomorphology and age of displaced late Holocene alluvial surfaces of the Taramakau River at Inchbonnie. Progressive avulsion and abandonment of the Taramakau floodplain, aided by fault movements during the late Holocene, have preserved a left-stepping fault scarp that grows in height to the northeast. Surveyed dextral (22.5 ± 2 m) and vertical (4.8 ± 0.5 m) displacements across a left stepover in the fault across an alluvial surface are combined with a precise maximum age from a remnant tree stump (≥1590–1730 yr) to yield dextral, vertical, and reverse-slip rates of 13.6 ± 1.8, 2.9 ± 0.4, and 3.4 ± 0.6 mm/yr, respectively. These values are larger (dextral) and smaller (dip slip) than previous estimates for this site, but they refl ect advances in the local chronology of surfaces and represent improved time-averaged results over 1.7 k.y. A geological kinematic circuit constructed for the central South Island demonstrates that (1) 69%–89% of the Australian-Pacific plate motion is accommodated by the major faults (Alpine-Hope-Kakapo) in this transitional area, (2) the 50% drop in slip rate on the Alpine fault between Hokitika and Inchbonnie is taken up by the Hope and Kakapo faults at the southwestern edge of the Marlborough Fault System, and (3) the new slip rates are more compatible with contemporary models of strain partitioning presented from geodesy.
    Description: Published
    Description: 139-152
    Description: 3.2. Tettonica attiva
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: N/A or not JCR
    Description: reserved
    Keywords: Alpine fault ; plate boundary ; slip rate ; New Zealand ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 46
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    Calibration and validation of reservoir models: the importance of high resolution, quantitative outcrop analogues (2010)
    The Geological Society of London
    Details
    Publication Date: 2021-11-09
    Description: Rapidly developing methods of digital acquisition, visualization and analysis allow highly detailed outcrop models to be constructed, and used as analogues to provide quantitative information about sedimentological and structural architectures from reservoir to subseismic scales of observation. Terrestrial laser-scanning (lidar) and high precision Real-Time Kinematic GPS are key survey technologies for data acquisition. 3D visualization facilities are used when analysing the outcrop data. Analysis of laser-scan data involves picking of the point-cloud to derive interpolated stratigraphic and structural surfaces. The resultant data can be used as input for object-based models, or can be cellularized and upscaled for use in grid-based reservoir modelling. Outcrop data can also be used to calibrate numerical models of geological processes such as the development and growth of folds, and the initiation and propagation of fractures.
    Description: Published
    Description: 87–98
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: N/A or not JCR
    Description: reserved
    Keywords: Laser-Scanning ; Outcrop analogues ; Reservoirs ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
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  • 47
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    Possible causes of arc development in the Apennines, central Italy (2010)
    Geological Society of America
    Details
    Publication Date: 2022-06-14
    Description: In central Italy, the geometry, kinematics, and tectonic evolution of the late Neogene Umbrian Arc, which is one of the main thrusts of the northern Apennines, have long been studied. Documented evidence for orogenic curvature includes vertical axis rotations along both limbs of the arc and a positive orocline test along the entire arc. The cause of the curvature is, however, still unexplained. In this work, we focus our attention on the southern portion of the Umbrian Arc, the so-called Olevano- Antrodoco thrust. We analyze, in particular, gravity and seismic-reflection data and consider available paleomagnetic, stratigraphic, structural, and topographic evidence from the central Apennines to infer spatial extent, attitude, and surface effects of a midcrustal anticlinorium imaged in the CROP-11 deep seismic profile. The anticlinorium has horizontal dimensions of ~50 by 30 km, and it is located right beneath the Olevano- Antrodoco thrust. Stratigraphic, structural, and topographic evidence suggests that the anticlinorium produced a surface uplift during its growth in early Pliocene times. We propose an evolutionary model in which, during late Neogene time, the Olevano- Antrodoco thrust developed in an out-of sequence fashion and underwent ~16° of clockwise rotation when the thrust ran into and was then raised and folded by the growing anticlinorium (late Messinian–early Pliocene time). This new model suggests a causal link between midcrustal folding and surficial orogenic curvature that is consistent with several available data sets from the northern and central Apennines; more evidence is, however, needed to fully test our hypothesis. Additionally, due to the occurrence of midcrustal basement-involved thrusts in other orogens, this model may be a viable mechanism for arc formation elsewhere.
    Description: Published
    Description: 1409-1420
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: oroclines ; Apennines ; fold and thrust belts ; gravity anomalies ; seismic reflection profiles ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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