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  • Artikel  (65)
  • Artikel (Open Access)  (65)
  • 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism  (28)
  • 04. Solid Earth::04.04. Geology::04.04.09. Structural geology  (21)
  • Mt. Etna  (16)
  • Aeolian Islands, Vulcano
  • Creep observations and analysis
  • AGU  (36)
  • Geological Society of America  (19)
  • Wiley  (5)
  • Agu  (4)
  • American Geophysical Union (AGU)
  • EGU - Copernicus
  • Egu-Copernicus
  • Frontiers Media S.A.
  • Wiley-AGU
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  • Artikel  (65)
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  • Artikel (Open Access)  (65)
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  • 1
    Publikationsdatum: 2020-11-26
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 63-66
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 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)
    Materialart: article
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  • 2
    Publikationsdatum: 2021-05-17
    Beschreibung: At least two transient events of extreme global warming occurred superimposed on the long-term latest Paleocene and early Eocene warming trend in the Paleocene-Eocene thermal maximum (PETM) (or ETM1 ~55.5 Ma) and the Elmo (or ETM2 ~53.6 Ma). Other than warmth, the best known PETM is characterized by (1) significant injection of 13C-depleted carbon into the ocean-atmosphere system, (2) deep-sea carbonate dissolution, (3) strong biotic responses, and (4) perturbations of the hydrological cycle. Documentation of the other documented and suspected "hyperthermals" is, as yet, insufficient to assess whether they are similar in nature to the PETM. Here we present and discuss biomagnetostratigraphic data and geochemical records across two lower Eocene successions deposited on a continental margin of the western Tethys: the Farra and Possagno sections in the Venetian pre-Alps. We recognize four negative carbon isotope excursions within chron C24. Three of these shifts correlate to known or suspected hyperthermals: the PETM, the Eocene thermal maximum 2 (~53.6 Ma), and the informally named "X event" (~52.5 Ma). The fourth excursion lies within a reverse subchron and occurred between the latter two. In the Farra section, the X event is marked by a ~0.6% negative carbon isotope excursion and carbonate dissolution. Furthermore, the event exhibits responses among calcareous nannofossils, planktic foraminifera, and dinoflagellates that are similar to, though less intense than, those observed across the PETM. Sedimentological and quantitative micropaleontological data from the Farra section also suggest increased weathering and runoff as well as sea surface eutrophication during this event.
    Beschreibung: Published
    Beschreibung: PA2209
    Beschreibung: 2.2. Laboratorio di paleomagnetismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Paleoclimate ; Hyperthermal events ; Early Eocene ; Bio-magnetostratigraphy ; Geochemistry ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 3
    Publikationsdatum: 2021-06-25
    Beschreibung: The Antarctic Geological Drilling (ANDRILL) program — a collaboration between Germany, Italy, New Zealand, and the United States that is one of the larger programs endorsed by the International Polar Year (IPY; http:// www .ipy .org) — successfully completed the drilling phase of the Southern McMurdo Sound (SMS) Project in December 2007. This second drill core of the program’s campaign in the western Ross Sea, Antarctica, complements the results of the first drilling season [Naish et al., 2007] by penetrating deeper into the stratigraphic section in the Victoria Land Basin and extending the recovered time interval back to approximately 20 million years ago.
    Beschreibung: Published
    Beschreibung: 89-90
    Beschreibung: 1.8. Osservazioni di geofisica ambientale
    Beschreibung: 2.2. Laboratorio di paleomagnetismo
    Beschreibung: N/A or not JCR
    Beschreibung: reserved
    Schlagwort(e): ANDRILL ; SMS Project ; MMCO (Middle Miocene Climatic Optimum) ; 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::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2021-05-25
    Beschreibung: The 1974 western flank eruption of Mount Etna produced a rare, nearly aphyric and plagioclase-free trachybasalt that could not be derived from the central volcano conduits and was more alkaline and more radiogenic than all previous historical lavas. New results for the petrochemistry and volatile content of its products, combined with contemporaneous seismic and volcanological observations, allow us to reinterpret the origin and significance of this event. We show that the eruption was most likely triggered by deep tectonic fracturing that allowed a dike-like intrusion to propagate in 9 days from 11 km depth up to the surface, bypassing the central conduits. Relatively fast, closed system decompression of the volatile-rich magma initially led to lava fountaining and the rapid growth of two pyroclastic cones (Mounts De Fiore), followed by Strombolian activity and the extrusion of viscous lava flows when gas-melt separation developed in the upper portion of the feeding fracture. The 1974 trachybasalt geochemistry indicates its derivation by mixing 25% of preexisting K-poor magma (best represented by 1763 La Montagnola eruption’s products) and 75% of a new K-rich feeding magma that was gradually invading Mount Etna’s plumbing system and became directly extruded during two violent flank eruptions in 2001–2003. We propose to classify 1974-type so-called ‘‘eccentric’’ eruptions on Etna as deep dike-fed (DDF) eruptions, as opposed to more common central conduit-fed flank eruptions, in order to highlight their actual origin rather than their topographic location. We ultimately discuss the possible precursors of such DDF eruptions.
    Beschreibung: Published
    Beschreibung: B07204
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 1974 deep dike-fed eruption ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 5
    Publikationsdatum: 2021-05-17
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 1175-1178
    Beschreibung: 4T. Fisica dei terremoti e scenari cosismici
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): 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)
    Materialart: article
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  • 6
    Publikationsdatum: 2017-04-04
    Beschreibung: Radon emissions are frequently monitored in volcanically and tectonically active areas in order to reveal changes in soil degassing, as radon acts a tracer for the more abundant CO2 degassing commonly observed in such areas. Between July 2002 and May 2003 a series of discrete measurements of radon concentrations in soil were made with high spatial resolution (∼5–100 m) in the Santa Venerina area on Mt. Etna. These measurements revealed well-defined linear anomalies that we interpret as being caused by active faults whose higher porosity than surrounding soils allows an increased CO2 flux, carrying radon from beneath. These faults were not visible at the surface and were therefore revealed at high spatial resolution by our radon survey. Our hypothesis that the positive anomalies are attributable to active faults was strengthened by the observation of concentrated damage along this geometry during the earthquakes that struck this area in late October 2003.
    Beschreibung: Published
    Beschreibung: 4
    Beschreibung: partially_open
    Schlagwort(e): Structural Geology: Role of fluids ; Structural Geology: Fractures and faults ; Structural Geology: Instruments and techniques ; Volcanology: Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Format: 713186 bytes
    Format: 490 bytes
    Format: application/pdf
    Format: text/html
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  • 7
    Publikationsdatum: 2017-04-04
    Beschreibung: This study concerns the unstable scarp named Sciara del Fuoco (SDF) at Stromboli volcano, merging geostructural observations, live-cam records in the visible and IR bands, analysis of vertical aerial photographs, and seismic records. These are used to assess morpho-structural changes between 2002 and 2004. The onset of the lava effusion on 28 December, 2002 preceded a gravitational collapse by two days, affecting a wide area of the SDF above and below sea level. We surmise that the collapse enhanced latent instability of the scarp. The 2002–2003 lava flows had a remarkable stabilizing effect on wide portions (〉50%) of the SDF, whilst erosive phenomena continued in the zone not covered by lava. This caused unrelenting regression of the upper landslide scarp toward the summit craters in the form of rockfalls and debris flows. If the crater conduit were involved in the sliding, then a change in eruptive behavior cannot be excluded.
    Beschreibung: Published
    Beschreibung: L09304
    Beschreibung: reserved
    Schlagwort(e): NONE ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 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)
    Materialart: article
    Format: 3767834 bytes
    Format: application/pdf
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  • 8
    Publikationsdatum: 2017-04-04
    Beschreibung: We report here on the real-time measurement of CO2 and SO2 concentrations in the near-vent volcanic gas plume of Mount Etna, acquired by the use of a field portable gas analyzer during a series of periodic field surveys on the volcano’s summit. During the investigated period (September 2004 to September 2005), the plume CO2/SO2 ratio ranged from 1.9 to 10.8, with contrasting composition for Northeast and Voragine crater plumes. Scaling the above CO2/SO2 ratios by UV spectroscopy determined SO2 emission rates, we estimate CO2 emission rates from the volcano in the range 0.9–67.5 kt d 1 (average, 9 kt d 1). About 2 kt of CO2 were emitted daily on average during quiescent passive degassing, whereas CO2 emission rates from Etna’s summit were 10–40 times larger during the 2004–2005 effusive event (with a cumulative CO2 release of 3800 kt during the 6 months of the eruption). Such a syneruptive increase, ascribed to the replenishment of the shallow (〈6 km) volcanic plumbing system by CO2-rich (0.25 wt %) more primitive magmas, supports the potential of CO2 output rates as key parameters for volcanic hazard assessment.
    Beschreibung: Published
    Beschreibung: B09207
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): carbon dioxide ; Mt. Etna ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
    Publikationsdatum: 2017-04-04
    Beschreibung: We report on 270 paleomagnetic directions retrieved from 17 different spatter deposits spread over the northern and western flanks of the Stromboli volcano (Aeolian Islands, Italy). The spatter were emplaced during previously undated high-energy Strombolian eruptions occurring after the third-seventh century AD. Our paleomagnetic directions were superimposed over the paleosecular variation curve of the geomagnetic field for the last two millennia, obtained by reducing to the coordinates of Stromboli the archeomagnetic and magnetic observatory data from France and Italy. This comparison suggests that most of the spatter exposed in the northern flank of the volcano were emplaced during several eruptions occurring between ca. 1400 and 1600 AD, while the western flank of Stromboli was diffusely spread by spatter during the powerful XX century eruptions. Conversely, there is no evidence for paroxysmal fire fountain activity occurring before 1400 AD, and between 1600 and 1907 AD.
    Beschreibung: Published
    Beschreibung: L02607
    Beschreibung: 2.2. Laboratorio di paleomagnetismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Geomagnetism and Paleomagnetism ; Stromboli volcano, Aeolian Islands, Italy ; Paleomagnetic secular variations ; Paleomagnetic dating ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2017-04-04
    Beschreibung: Ground deformation data from GPS and differential synthetic aperture radar interferometry (DInSAR) techniques are analyzed to study the July–August 2001 Mount Etna eruption as well as the dynamics preceding and following this event. Five GPS surveys were carried out on the entire Mount Etna network or on its southeastern part, from July 2000 to October 2001. Five ERS-2 ascending passes and three descending ones are used to form five interferograms spanning periods from a month to 1 year, before and encompassing the eruption. Numerical and analytical inversions of the GPS and DInSAR data were performed to obtain analytical models for preeruptive, syneruptive and posteruptive periods. The deformation sources obtained were from the Mogi model: (1) pressure sources located beneath the upper western flank of the volcano, inflating before the eruption onset and deflating afterward; (2) tensile dislocations to model the intrusion of a N-S dike in the central part of the volcano; and (3) two sliding and two normal dislocations to model the eastern and southern flank dynamics. This study confirms that the lower vents of the eruption were fed by a magma stored at depth ranging from 9 to 4 km below sea level, as proposed from petrochemical and geophysical researches. The rising of the magma through the shallow crust started months before the eruption onset but accelerated on the last day; this study suggests that in the volcanic pile the path of the rising magma was driven by the volcano topography. The eastern sliding plane and the interaction between dike intrusion and flank instability have been better defined with respect to previous studies. The sliding motion abruptly accelerated with the dike intrusion, and this continued after the end of the eruption. The acceleration was accompanied by the propagation of the strain field toward the eastern periphery of the volcano.
    Beschreibung: We acknowledge the ‘‘Istituto Nazionale di Geofisica e Vulcanologia’’, the Italian ‘‘Dipartimento per la Protezione Civile’’ and the European Community (contract INGV-DPC UR V3_6/36 and VOLUME Project) for their economic contribution to this research. The SAR data are provided by ESA-ESRIN.
    Beschreibung: Published
    Beschreibung: B06405
    Beschreibung: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Ground deformation ; GPS ; InSAR ; Mt. Etna ; Modelling ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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