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  • 04. Solid Earth::04.04. Geology::04.04.09. Structural geology  (18)
  • Geological Society of America  (10)
  • Elsevier B.V.  (5)
  • Geological Society of London  (2)
  • MDPI Publishing
  • Nature Publishing Group
Collection
Publisher
Years
  • 1
    Publication Date: 2020-11-26
    Description: Solidified frictional melts, or pseudotachylytes, remain the only unambiguous indicator of seismic slip in the geological record. However, pseudotachylytes form at 〉5 km depth, and there are many rock types in which they do not form at all. We performed low- to high-velocity rock friction experiments designed to impose realistic coseismic slip pulses on calcite fault gouges, and report that localized dynamic recrystallization may be an easy-to-recognize microstructural indicator of seismic slip in shallow, otherwise brittle fault zones. Calcite gouges with starting grain size 〈250 μm were confined up to 26 MPa normal stress using a purpose-built sample holder. Slip velocities were between 0.01 and 3.4 m s−1, and total displacements between 1 and 4 m. At coseismic slip velocities ≥0.1 m s−1, the gouges were cut by reflective principal slip surfaces lined by polygonal grains 〈1 μm in size. The principal slip surfaces were flanked by 〈300 μm thick layers of dynamically recrystallized calcite (grain size 1–10 μm) containing well-defined shape- and crystallographic-preferred orientations. Dynamic recrystallization was accompanied by fault weakening and thermal decomposition of calcite to CO2 + CaO. The recrystallized calcite aggregates resemble those found along the principal slip surface of the Garam thrust, South Korea, exhumed from 〈5 km depth. We suggest that intense frictional heating along the experimental and natural principal slip surfaces resulted in localized dynamic recrystallization, a microstructure that may be diagnostic of seismic slip in the shallow crust.
    Description: Published
    Description: 63-66
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: JCR Journal
    Description: reserved
    Keywords: Rock mechanics ; shallow earthquales ; 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::04.04. Geology::04.04.09. Structural geology ; 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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  • 2
    Publication Date: 2021-05-17
    Description: Earthquakes occur along faults in response to plate tectonic movements, but paradoxically, are not widely recognized in the geological record, severely limiting our knowledge of earthquake physics and hampering accurate assessments of seismic hazard. Light-reflective (so-called mirror like) fault surfaces are widely observed geological features, especially in carbonate-bearing rocks of the shallow crust. Here we report on the occurrence of mirror-like fault surfaces cutting dolostone gouges in the Italian Alps. Using friction experiments, we demonstrate that the mirror-like surfaces develop only at seismic slip rates (∼1 m/s) and for applied normal stresses and sliding displacements consistent with those estimated on the natural faults. Under these experimental conditions, the frictional power density dissipated in the samples is comparable to that estimated for natural earthquakes (1–10 MW/m2). Our results indicate that mirror-like surfaces in dolostone gouges are a signature of seismic faulting, and can be used to estimate power dissipation during ancient earthquake ruptures.
    Description: Published
    Description: 1175-1178
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: JCR Journal
    Description: reserved
    Keywords: Earthquakes ; Faults ; Carbonates ; Rock Mechanics ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 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::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2017-04-04
    Description: In this paper, we describe the 1809 eruption of Mt. Etna, Italy, which represents one historical rare case in which it is possible to observe details of the internal structure of the feeder system. This is possible thanks to the presence of two large pit craters located in the middle of the eruptive fracture field that allow studying a section of the shallow feeder system. Along the walls of one of these craters, we analysed well-exposed cross sections of the uppermost 15–20 m of the feeder system and related volcanic products. Here, we describe the structure, morphology and lithology of this portion of the 1809 feeder system, including the host rock which conditioned the propagation of the dyke, and compare the results with other recent eruptions. Finally, we propose the dynamic model of the magma behaviour inside a laterally-propagating feeder dyke, demonstrating how this dynamic triggered important changes in the eruptive style (from effusive/Strombolian to phreatomagmatic) during the same eruption. Our results are also useful for hazard assessment related to the development of flank eruptions, potentially the most hazardous type of eruption from basaltic volcanoes in densely urbanized areas, such as Mt. Etna.
    Description: Published
    Description: 1-11
    Description: 2T. Tettonica attiva
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: 4V. Vulcani e ambiente
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: N/A or not JCR
    Description: open
    Keywords: feeder dyke ; basaltic volcanoes ; flank eruptions ; Etna ; volcanic hazards ; sill ; volcanic rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 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::04.08.04. Thermodynamics ; 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::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    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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  • 5
    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)
    Type: article
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  • 6
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 13
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    Unknown
    Geological Society of America
    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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  • 14
    Publication Date: 2017-04-04
    Description: On 27 February 2007, two NE–SW and NNW–SSE dike-fed effusive vents opened to the North (at 650 and 400 m above sea level, asl) of the summit craters at Stromboli, forming a fissure parallel to the inner walls of the Sciara del Fuoco (SdF) sector collapse depression. The formation of these vents was soon followed by rapid subsidence of the summit crater area. This partly obstructed the central conduit, temporarily choking the fissure and increasing the deformation of the upper part of SdF. The reactivation of the NNW–SSE vent and the opening of a new vent located at 500 m asl, fed by a second dike, released the internal pressure and surface deformation ceased. The eruption then continued again from the 400 m vent, after a summit explosion on 15 March, until ending in early April after a progressive decrease of magma output. Repeated NE–SW dike intrusions have occurred in recent years, close to the upper SE limit of the SdF. In that zone, named Bastimento, the eruptive fractures traced the discontinuities that borders the SdF, increasing the risk of triggering new sector collapse. Whereas the NE–SW trending structures lie along the regional volcanostructural trend of the Aeolian arc through Stromboli, the NNW–SSE vents are oblique to this trend and may be controlled by the anomalous stress field within the unstable flank of the SdF. Another fundamental aspect of the 2007 eruption is the collapse of the central conduit, due to the rapid and deep magma drainage linked to the opening of the 400 m vent. The intrusion of dikes and development of flank vents during the 2007 eruption could possibly have triggered catastrophic landslides and related tsunami or eruptive paroxysms, but the opening of new effusive vents released the internal pressures, diminishing the hazard.
    Description: Work funded by INGV and Dipartimento Protezione Civile, Italy.
    Description: Published
    Description: 137-144
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    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: 2007 Stromboli eruption ; Dike-Fed vent ; Volcano-Tectonics ; Conduit collapse ; Flank instability ; 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::04.04.09. 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::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 15
    Publication Date: 2020-11-26
    Description: We describe the evolution of the volcanic activity and deformation patterns observed at Mount Etna during the July–August 2001 eruption. Seismicity started at 3000 m below sea level on 13 July, accompanied by moderate ground swelling. Ground deformation culminated on 16 July with the development of a NE–SW graben c. 500 m wide and c. 1 m deep in the Cisternazza area at 2600–2500 m above sea level on the southern slope of the volcano. On 17 July, the eruption started at the summit of Mount Etna from the SE Crater (central–lateral eruptive system), from which two radial, c. 30 m wide, c. 3000 m long fracture zones, associated with eruptive fissures, propagated both southward (17 July) and northeastward (20 July). On 18 July, a new vent formed at 2100 m elevation, at the southern base of the Montagnola, followed on the next day by the opening of a vent further upslope, at 2550 m (eccentric eruptive system). The eruption lasted for 3 weeks. Approximately 80% of the total lava volume was erupted from the 2100 m and the 2550 m vents. The collected structural data suggest that the Cisternazza graben developed as a passive local response of the volcanic edifice to the ascent of a north–south eccentric dyke, which eventually reached the ground surface in the Montagnola area (18–19 July). In contrast, the two narrow fracture zones radiating from the summit are interpreted as the lateral propagation, from the conduit of the SE Crater, of north–south- and NE–SW-oriented shallow dykes, 2–3 m wide. The evolution of the fracture pattern together with other volcanological data (magma ascent and effusion rate, eruptive style, petrochemical characteristics of the erupted products, and petrology of xenoliths within magma) suggest that the eccentric and central–lateral eruptions were fed by two distinct magmatic systems. Examples of eccentric activity accompanied by central–lateral events have never been described before at Etna.
    Description: Published
    Description: 531-544
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Mount Etna ; July–August 2001 Eruption ; magmas ; dykes ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 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::04.08.03. Magmas ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 16
    Publication Date: 2017-04-03
    Description: In September 2002, a series of tectonic earthquakes occurred north of Sicily, Italy, followed by three events of volcanic unrest within 150 km. On October 28, 2002, Mt. Etna erupted; on November 3, 2002, submarine degassing occurred near Panarea Island; and on December 28, 2002, Stromboli Island erupted. All of these events were considered unusual: the Mt. Etna NE-rift eruption was the largest in 55 yr, the Panarea degassing was one of the strongest ever detected there, and the Stromboli eruption, which produced a landslide and tsunami, was the largest effusive eruption in 17 yr. Here, we investigate the synchronous occurrence of these clustered unrest events, and develop a possible explanatory model. We compute short-term earthquake-induced dynamic strain changes and compare them to long-term tectonic effects. Results suggest that the earthquake-induced strain changes exceeded annual tectonic strains by at least an order of magnitude. This agitation occurred in seconds, and may have induced fluid and gas pressure migration within the already active hydrothermal and magmatic systems.
    Description: In press
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.1. Fisica dei terremoti
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: earthquake trigger ; magma and gas eruptions ; 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::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 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::04.07.04. Plate boundaries, motion, and tectonics ; 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::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 17
    Publication Date: 2017-04-04
    Description: An example of sheet-like intrusion emplacement at very shallow crustal levels on Elba Island, Italy, is described. The Eastern Elba Dyke Complex (EEDC) consists of decimetre- to metre-thick sheeted aplites emplaced within intensely folded low-grade metamorphic rocks. Field data indicate that sill and dyke emplacement was controlled by mechanical discontinuities, represented by fractures in the host rocks, and was strongly favoured by magma overpressure. The occurrence of angular fragments of host rocks in the dyke border zones and the branching of sills testify to hydraulic fracturing. Analysis of the spatial distribution and geometry of EEDC sills and dykes provides clues on fluid pressure conditions and the stress state at the time of magma emplacement, as well as on the depth of emplacement. The calculated stress ratio and driving pressure ratio were used to estimate a magma overpressure of 6–54 MPa at the time of emplacement of the EEDC at a depth of about 2 km.
    Description: Published
    Description: 121-129
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: N/A or not JCR
    Description: reserved
    Keywords: Hydrofractures ; magma emplacement ; upper crust ; southern Tuscany ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 18
    Publication Date: 2017-04-04
    Description: Fissure eruptions may provide important information on the shallow propagation of dikes at volcanoes. Somma-Vesuvius (Italy) consists of the active Vesuvius cone, bordered to the north by the remnants of the older Somma edifice. Historical chronicles are considered to define the development of the 37 fissure eruptions between A.D. 1631 and 1944. The 1631 fissure, which reopened the magmatic conduit, migrated upward and was the only one triggered by the subvertical propagation of a dike. The other 25 fissure eruptions migrated downward, when the conduit was open, through the lateral propagation of radial dikes. We suggest two scenarios for the development of the fissures. When the summit conduit is closed, the fissures are fed by vertically propagating dikes. When the summit conduit is open, the fissures are fed by laterally propagating dikes along the volcano slopes. Consistent behaviors are found at other composite volcanoes, suggesting a general application to our model, independent of the tectonic setting and composition of magma. At Vesuvius, the historical data set and our scenarios are used to predict the consequences of the emplacement of fissures after the opening of the conduit. The results suggest that, even though the probability of opening of vents within the inhabited south and west slopes is negligible, the possibility that these are reached by a lava flow remains significant.
    Description: Published
    Description: 673-676
    Description: reserved
    Keywords: fissures ; dike propagation ; conduit ; Vesuvius ; 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::04.07.05. Stress
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 308433 bytes
    Format: application/pdf
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