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  • 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics  (4)
  • Mt. Etna
  • Elsevier Science Limited  (3)
  • Elsevier  (1)
  • Blackwell Publishing Ltd
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • Springer
  • Springer-Verlag
  • 2010-2014  (4)
  • 2005-2009
  • 2014  (4)
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Schlagwörter
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  • 2010-2014  (4)
  • 2005-2009
Jahr
  • 1
    Publikationsdatum: 2020-12-07
    Beschreibung: 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.
    Beschreibung: Published
    Beschreibung: 67-79
    Beschreibung: 1A. Geomagnetismo e Paleomagnetismo
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): 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)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2017-04-04
    Beschreibung: We made a stratigraphic, structural and morphologic study of Amiata Volcano in Italy. We find that the edifice is dissected by intersecting grabens that accommodate the collapse of the higher sectors of the volcano. In turn, a number of compressive structures and diapirs exist all around the margin of the volcano. These structures create an angular drainage pattern, with stream damming and captures, and a set of lakes within and around the volcano. We interpret these structures as the result of volcanic spreading of the edifice of Amiata onto its weak substratum, formed by the late Triassic evaporites (Anidriti of Burano) and the Middle-Jurassic to Early-Cretaceous clayey chaotic complexes (Ligurian Complex). Regional doming created a slope in the basement forcing the outward flow and spreading of the ductile layers below the volcano. We model the dynamics of spreading with a scaled lubrication approximation of the Navier Stokes equations, and numerically study a solution. In the model we include simple functions for volcanic deposition and surface erosion that change the topography over time. Scaling indicates that spreading at Amiata could still be active. The numerical solution shows that, as the central part of the edifice sinks into the weak basement, diapiric structures of the underlying formations form around the base of the volcano. Deposition of volcanic rocks within the volcano and surface erosion away from it both enhance spreading. In addition, a sloping basement may constitute a trigger for the formation of trains of adjacent diapirs. Finally, we observe that volcanic spreading has created ideal heat traps that constitute todays’ exploited geothermal fields at Amiata. Normal faults generated by volcanic spreading, volcanic conduits, and direct contact between volcanic rocks (which host an extensive fresh-water aquifer) and the rocks of the geothermal field, constitute ideal pathways for water recharge during vapour extraction for geothermal energy production. We think that volcanic spreading could maintain faults in a critically stressed state, facilitating the occurrence of triggered seismicity.
    Beschreibung: Published
    Beschreibung: 16-31
    Beschreibung: 1V. Storia e struttura dei sistemi vulcanici
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Amiata volcano ; geology ; structure ; volcanic spreading ; spreding model ; geothermal traps formation ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2017-04-04
    Beschreibung: We investigate the transfer zone and linkage between divergent extensional seismogenic fault systems on the border amid the central and southern Apennines (central Italy). These regional NW-SE striking sets include large seismogenic sources that caused major historical earthquakes (Mw≤7). The faults in the northern part of the study area dip to the southwest; those in the southern part dip to the northeast. The SW-dipping system (Abruzzi Apennines) terminates with the Aremogna-Cinque Miglia source; the NE-dipping system (southern Apennines) terminates with the Boiano Basin source. To test whether the transfer zone model applies to the central-southern Apennines border, we analyzed and relocated seismicity that occurred from 2007 to 2011 between the Aremogna-Cinque Miglia and Boiano Basin sources, where we expect the transfer zone. Seismicity is made of independent events (Md〈3.5) and low-magnitude swarms. West of the Apennines, hypocenters are located within the uppermost 12-13 km. Events and swarms that occurred east of the axis affect the 13-25 km below. West of the chain, focal mechanisms show T-axes striking ~NNW-SSE. East of the chain, T-axes strike ~NE-SW. This trend is consistent with GPS data. The hypocentral distribution of swarms located between the Aremogna-Cinque Miglia and Boiano Basin sources shows a ~NNE-SSW trend, coincident with part of the Ortona-Roccamonfina Line, a regional transverse lineament. The spatial distribution of seismicity, the geometry and kinematics of active faulting in the region, and results from previous geophysical studies, allow us to contend the existence of a transfer zone between these seismogenic normal fault systems. Our data also allow us to recognize the activity of such transfer along the central part of the Ortona-Roccamonfina Line. We infer that reverse in dip polarity between the two normal fault systems could also result from the passage between the diverse tectonic units composing the border between central and southern Apennines.
    Beschreibung: Published
    Beschreibung: 18-31
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): seismogenic sources ; seismic swarms ; transverse lineaments ; fault polarity ; transfer zone ; southern italy ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Publikationsdatum: 2017-10-19
    Beschreibung: Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrusttype focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≥ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east–west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on thewhole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including threecomponent seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks.
    Beschreibung: Published
    Beschreibung: 44-55
    Beschreibung: 2T. Tettonica attiva
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Seismology ; Hypocentral location ; Seismic sequence ; Velocity model ; Thrust fault system ; Po alluvial Plain ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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