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  • 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry  (58)
  • 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics  (47)
  • 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology  (40)
  • 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy  (38)
  • Mt. Etna  (30)
  • Elsevier  (170)
  • Springer-Verlag  (19)
  • Blackwell Publishing Ltd  (4)
  • ELSEVIER
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • 2010-2014  (71)
  • 2005-2009  (125)
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Keywords
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Years
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  • 1
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    A major change in the sedimentation regime in the Crotone Basin (Southern Italy) around 3.7-3.6 Ma (2014)
    Elsevier
    Details
    Publication Date: 2021-05-17
    Description: The Lower Pliocene succession of the Crotone Basin (Calabrian Arc, Southern Italy) is mainly comprised of blue-grey marly clay with good magnetic properties. Here the bio-magnetostratigraphic data indicate a mean sedimentation rate of about 12–15 cm/kyr. Around 3.7–3.6 Ma a major change in the sedimentation regime occurred: the blue-grey hemipelagic marls grade rapidly into silty marls with a significant increase in the terrigenous fraction and with abundant siliceous remains throughout the whole interval. Magnetic properties of these sediments are very poor, but an integrated calcareous plankton biostratigraphy (foraminifera and nannofossils) infers a high average sedimentation rate (about 50–60 cm/kyr). The abrupt onset of this sedimentation regime in the Crotone Basin is contemporaneous with a major unconformity already recognized in the northern sector of the basin, part of amajor reorganization phase in the whole Apenninic–Maghrebid Chain known as “Globorotalia puncticulata event”. Reports of coeval siliceous sediments in other marginal basins of the Apennines (Southern Calabria, Southern and Northern Apennines) suggest that this “siliceous event” might have been regionally extensive, having important palaeoceanographical implications.We infer that the “siliceous event” is characterized by a combined tectonic- and climate-induced change in palaeoceanographic conditions. The tectonic triggering factors may have been linked to two synchronous events in the Tyrrhenian–Apennine system: 1) the shortening event also known as “G. puncticulata event”, and 2) the coeval opening of the Vavilov Basin in the Tyrrhenian Sea which yielded profound influences in terms of physiography and characteristics of the Crotone Basin. The consequent uplift of the Southern Apennines would have increased sediment supply and availability of silica, resulting in eutrophication and enhanced silica preservation. Strong winter mixing and possibly upwelling conditions could have increased primary productivity during heavy isotope stages Gi4, Gi2 and MG8, at the onset of the “siliceous event”. This important event, lasting from ca. 3.6 Ma to ca. 3.2 Ma, would have recorded a peculiar transitional period before further climatic deterioration and more drastic palaeoceanographic changes occurred around 3.1 Ma, leading to cyclic sapropel deposition in the whole of the Mediterranean sea.
    Description: Published
    Description: 398-410
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Biostratigraphy ; Magnetostratigraphy ; Pliocene ; Calabrian Arc ; 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::04.07. Tectonophysics::04.07.02. Geodynamics
    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)
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  • 3
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    Repeating volcano-tectonic earthquakes at Mt. Etna volcano (Sicily, Italy) during 1999–2009 (2013)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Repeating volcano-tectonic (VT) earthquakes, taking place at Mt. Etna during 1999–2009,were detected and analyzed to investigate their behavior. We found 735 families amounting to 2479 VT earthquakes, representing ~38% of all the analyzed VT earthquakes. The number of VT earthquakes making up the families ranges from 2 to 23. Over 70% of the families comprise 2 or 3 VT earthquakes and only 20 families by more than 10 events. The occurrence lifetime is also highly variable ranging from some minutes to ten years. In particular, more than half of the families have a lifetime shorter than 0.5 day and only ~10% longer than 1 year. On the basis of these results, most of the detected families were considered “burst-type”, i.e., show swarm-like occurrence, and hence their origin cannot be explained by a temporally constant tectonic loading. Indeed, since the analyzed earthquakes take place in a volcanic area, the rocks are affected not only by tectonic stresses related to the fairly steady regional stress field but also by local stresses, caused by the volcano, such as magma batch intrusions/ movements and gravitational loading.We focused on the five groups of families characterized by the longest repeatability over time, namely high number of events and long lifetime, located in the north-eastern, eastern and southern flanks of the volcano. Unlike the first four groups, which similarly to most of the detected families show swarm-like VT occurrences, group “v”, located in the north-eastern sector, exhibits a more “tectonic” behavior with the events making up such a group spread over almost the entire analyzed period. It is clear how both occurrence and slip rates do not remain constant but vary over time, and such changes are time-related to the occurrence of the 2002–2003 eruption. Finally, by FPFIT algorithm a good agreement between directions identified by nodal planes and the earthquake epicentral distribution was generally found.
    Description: Published
    Description: 1223 – 1236
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: repeating earthquakes ; Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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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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  • 5
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    Wind as a main driver of the net ecosystem carbon balance of a semiarid Mediterranean steppe in the South East of Spain (2012)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2017-04-04
    Description: Despite the advance in our understanding of the carbon exchange between terrestrial ecosystems and the atmosphere, semiarid ecosystems have been poorly investigated and little is known about their role in the global carbon balance. We used eddy covariance measurements to determine the exchange of CO2 between a semiarid steppe and the atmosphere over 3 years. The vegetation is a perennial grassland of Stipa tenacissima L. located in the SE of Spain. We examined diurnal, seasonal and interannual variations in the net ecosystem carbon balance (NECB) in relation to biophysical variables. Cumulative NECB was a net source of 65.7, 143.6 and 92.1 g C mˉ2 yrˉ1 for the 3 years studied, respectively. We separated the year into two distinctive periods: dry period and growing season. The ecosystem was a net source of CO2 to the atmosphere, particularly during the dry period when large CO2 positive fluxes of up to 15 μmol mˉ2 sˉ1 were observed in concomitance with large wind speeds. Over the growing season, the ecosystem was a slight sink or neutral with maximum rates of -2.3 μmol mˉ2 sˉ1. Rainfall events caused large fluxes of CO2 to the atmosphere and determined the length of the growing season. In this season, photosynthetic photon flux density controlled day-time NECB just below 1000 μmol mˉ2 sˉ1. The analyses of the diurnal and seasonal data and preliminary geological and gas-geochemical evaluations, including C isotopic analyses, suggest that the CO2 released was not only biogenic but most likely included a component of geothermal origin, presumably related to deep fluids occurring in the area. These results highlight the importance of considering geological carbon sources, as well as the need to carefully interpret the results of eddy covariance partitioning techniques when applied in geologically active areas potentially affected by CO2-rich geofluid circulation.
    Description: Published
    Description: 539–554
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: alpha grass ; carbon sequestration ; ecosystem respiration ; eddy covariance ; geogas ; geothermal activity ; grasslands ; net ecosystem carbon balance ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    The deformation offshore of Mount Etna as imaged by multichannel seismic reflection profiles (2012)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Despite the clear evidence of active flank dynamics that is affecting the eastern side of Mount Etna, the contribution of tectonic processes has not been yet understood. So far, the various models proposed to explain the observed flank deformation have been based on onshore structural data, coming from the volcanic edifice. The Ionian offshore of Mount Etna has been only recently investigated using multichannel seismic profiles, and offers the opportunity to image the structural features of the substrate of the unstable flank of the volcano. This contribution aims at describing the deformation located offshore Mount Etna using multichannel seismic profiles recently acquired during three seismic surveys. The onshore flank deformation of Mount Etna appears to be laterally confined by two tectonic guidelines, trending roughly E–W, located to the north and south of the deforming flank; the northern guideline, in particular, takes the surface expression of a sharp fault (Pernicana Fault). Though often assumed that these boundary structures continue offshore as linear features, connected to a frontal thrust ramp, the occurrence of this simple offshore structural system has not been imaged. In fact, seismic data show a remarkable degree of structural complexity offshore Mount Etna. The Pernicana Fault, for instance, is not continuing offshore as a sharp feature; rather, the deformation is expressed as ENE–WSW folds located very close to the coastline. It is possible that these tectonic structures might have affected the offshore of Mount Etna before the Pernicana Fault system was developed, less than 15 ka ago. The southern guideline of the collapsing eastern flank of the volcano is poorly expressed onshore, and does not show up offshore; in fact, seismic data indicate that the Catania canyon, a remarkable E–W-trending feature, does not reflect a tectonic control. Seismic interpretation also shows the occurrence of a structural high located just offshore the edifice of Mount Etna. Whereas a complex deformation affects the boundary of this offshore bulge, it shows only limited internal deformation. Part of the topography of the offshore bulge pre-existed the constructional phase of Mount Etna, being an extension of the Hyblean Plateau. Only in the northern part, the bulge is a recent tectonic feature, being composed by Plio-Quaternary strata that were folded before and during the building of Mount Etna. The offshore bulge is bounded by a thrust fault that can be related to the intrusion of the large-scale magmatic body below Mount Etna.
    Description: Published
    Description: 50-64
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: restricted
    Keywords: Mount Etna offshore ; Volcano flank instability ; Active tectonics ; Multichannel reflection seismics ; Intrusive body ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism
    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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    Splitting parameter yield (SPY): A program for semiautomatic analysis of shear wave splitting (2012)
    Elsevier
    Details
    Publication Date: 2017-04-03
    Description: SPY is a Matlab algorithm that analyzes seismic waveforms in a semiautomatic way, providing estimates of the two observables of the anisotropy: the shear-wave splitting parameters. We chose to exploit those computational processes that require less intervention by the user, gaining objectivity and reliability as a result. The algorithm joins the covariance matrix and the cross-correlation techniques, and all the computation steps are interspersed by several automatic checks intended to verify the reliability of the yields. The resulting semiautomation generates two new advantages in the field of anisotropy studies: handling a huge amount of data at the same time, and comparing different yields. From this perspective, SPY has been developed in the Matlab environment, which is widespread, versatile, and user-friendly. Our intention is to provide the scientific community with a new monitoring tool for tracking the temporal variations of the crustal stress field.
    Description: Published
    Description: 138-145
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Crustal anisotropy ; Waveform analysis ; Seismic monitoring ; Stress field ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Paroxysmal activity at Stromboli: lessons from the past (2012)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: The persistent normal activity of Stromboli is occasionally interrupted by sudden and highly energetic explosive events called Strombolian paroxysms. These phenomena together with landslide-generated tsunamis represent the most hazardous manifestations of present-day volcanic activity at Stromboli. The most recent paroxysms, on 5 April 2003 and 15 March 2007, have drawn attention to these energetic events because they significantly threatened inhabitants and tourists. Historical accounts and field evidence indicate, however, that even larger paroxysms, in terms of volume, dispersal of products and intensity of explosive phenomena, occurred in the recent past. During these paroxysms incipiently welded spatter deposits mantled the north and south rims of the Sciara del Fuoco down to low elevations, extending much farther than the similar deposits from recent observed events (5 April 2003 and 15 March 2007). In order to identify, characterize and discriminate among products of these outstanding spatter-forming eruptions, more than 50 stratigraphic sections were measured and sampled. Stratigraphic, sedimentological and radiometric (14C) data indicate that only two paroxysms produced spatter that reached very low elevations and inhabited areas: the first occurred in the 16th century and the last in AD 1930. Analysis of texture and deposit components reveals that the early phases of the two eruptions were driven by distinctly different eruptive dynamics. Both identified paroxysms are at least one order of magnitude greater than any similar event observed by monitoring systems at Stromboli. These two large paroxysms were the most powerful volcanic events at Stromboli in the last eighteen centuries.
    Description: Published
    Description: 1229-1243
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Paroxysms ; Spatter ; Basaltic explosive volcanism ; Volcanic hazard ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Pattern recognition of volcanic tremor data on Mt. Etna (Italy) with KKAnalysis — A software program for unsupervised classification (2012)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Continuous seismic monitoring plays a key role in the surveillance of the Mt. Etna volcano. Besides earthquakes, which often herald eruptive episodes, the persistent background signal, known as volcanic tremor, provides important information on the volcano status. Changes in the regimes of activity are usually concurrent with variations in tremor characteristics. As continuous recording leads rapidly to the accumulation of large amounts of data, parameter extraction and automated processing become crucial. We propose techniques of unsupervised classification and present a software, named KKAnalysis, developed for this purpose. Essentials of KKAnalysis are demonstrated on tremor data recorded on Mt. Etna during various states of volcanic activity encountered in 2007 and 2008. KKAnalysis is based on MATLAB and combines various unsupervised pattern recognition techniques, in particular self-organizing maps (SOM) and cluster analysis. An early software version was successfully applied to seismic signals recorded on Mt. Etna during the eruption in 2001. Since each situation may require different configurations, we designed KKAnalysis with a specific GUI allowing users to easily modify parameters. All results are given graphically, in screen plots and metafiles (MATLAB and TIF format), as well as in alphanumeric form. The synoptic visualization of results from SOM and cluster analysis facilitates an immediate inspection. The potential of this representation is demonstrated by focusing on data recorded during a flank eruption on May 13, 2008. Changes of tremor characteristics can be clearly identified at a very early stage, well before enhanced volcanic activity becomes visible in the time series. At the same time, data reduction to less than 1% of the original amount is achieved, which facilitates interpretation and storage of the essential information. Running the program in a typical configuration requires computing time less than 1 min, allowing an on-line application for early warning purposes at INGV–Sezione di Catania
    Description: Published
    Description: 953-961
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 5.6. TTC - Attività di Sala Operativa
    Description: JCR Journal
    Description: reserved
    Keywords: Self-Organizing Map ; Cluster Analysis ; K-means ; Fuzzy C-means ; Volcano Seismology ; Volcano Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Stratigraphy and significance of Brown Tuffs on the Aeolian Islands (southern Italy) (2012)
    Elsevier
    Details
    Publication Date: 2021-12-06
    Description: Brown Tuffs (BT) are volcaniclastic ash deposits prominently represented in the stratigraphic profiles of all the Aeolian Islands (and Capo Milazzo on the northern coast of Sicily). Detailed stratigraphy and tephrochronology together with available radiometric ages suggest that they were emplaced over a long time interval spanning from the end of the last interglacial period (ca. 80 ka BP) up to 4–5 ka BP (age of the overlying Punte Nere pyroclastic products on Vulcano). The most complete BT succession is documented on Lipari where 14 distinct and successive units are subdivided by the interbedding of widespread tephra layers, local volcanic products, paleosols and epiclastic deposits and the occurrence of local erosive surfaces. Inter-island occurrence of Ischia-Tephra (a widely known tephra layer in the Aeolian archipelago dated at 56 ka BP) and Monte Guardia pyroclastics from Lipari (dated at 22–20 ka BP) subdivides the BT succession in Upper (UBT), Intermediate (IBT) and Lower BT units (LBT), which can be correlated at regional level: the LBT was emplaced between 80 and 56 ka BP, the IBT between 56 and 22 ka BP and the UBT between 20 and 4–5 ka BP. On the basis of stratigraphy, similarity in lithology and textural features, morphology of glass fragments, composition and consistency of thickness and grain-size variations, UBT units correlate with Piano Grotte dei Rossi tuffs on Vulcano island. They were generated by pulsating hydromagmatic explosive activity giving rise to pyroclastic density currents spreading laterally from a source located inside the La Fossa caldera on Vulcano island. Composition is in agreement with this hypothesis since UBT compositional features match those of Vulcano magmas erupted in that period. The effect of co-ignimbrite ash clouds (or associated fallout processes from sustained eruptive columns) is seen to explain the presence of UBT in areas further away from the suggested source (e.g. Salina and Lipari islands and Capo Milazzo). The origin of UBT exposed on Panarea island is still a matter of debate, due to contrasting compositional data. Due to large uniformity of lithological, textural and componentry characters with respect to the UBT, the lower portions of the BT succession (LBT-IBT) are considered to be the result of recurrent, large scale hydromagmatic eruptions of similar type. Moreover, for the IBT units, the correlation with Monte Molineddo 3 pyroclastics of Vulcano island (on the basis of lithological, compositional and stratigraphic matching) again suggests source(s) related to the Vulcano plumbing system and located within the La Fossa Caldera.
    Description: Published
    Description: 49-70
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: stratigraphy ; tephrocronology ; Brown Tuffs ; hydromagmatic eruption ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
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  • 12
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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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  • 13
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    Strain accumulation across the Messina Straits and kinematics of Sicily and Calabria from GPS data and dislocation modeling (2011)
    Elsevier
    Details
    Publication Date: 2020-12-03
    Description: We use Global Positioning System (GPS) velocities and dislocation modeling to investigate the rate and nature of interseismic strain accumulation in the area affected by the 1908 Mw 7.1 Messina earthquake (southern Italy) within the framework of the complex central Mediterranean microplate kinematics. Our data confirm a change in the velocity trends between Sicily and Calabria, moving from NNW-ward to NE- ward with respect to Eurasia, and detail a fan-like pattern across the Messina Straits where maximum extensional strain rates are ~65 nanostrains/yr. Extension normal to the coast of northern Sicily is consistent with the presence of SW–NE trending normal faults. Half-space dislocation models of the GPS velocities are used to infer the slip-rates and geometric fault parameters of the fault zone that ruptured in the Messina − 1.3 earthquake. The inversion, and the bootstrap analysis of model uncertainties, finds optimal values of 3. 5 + 2.0 − 0.2− 0.7 and 1.6 + 0.3 mm/yr for the dip–slip and strike–slip components, respectively, along a 30 + 1.1° SE-ward dipping normal fault, locked above 7.6−2.9 km depth. By developing a regional elastic block model that + 4.6 accounts for both crustal block rotations and strain loading at block-bounding faults, and adopting two different competing models for the Ionian–Calabria convergence rates, we show that the measured velocity gradient across the Messina Straits may be significantly affected by the elastic strain contribution from other nearby faults. In particular, when considering the contribution of the possibly locked Calabrian subduction interface onto the observed velocity gradients in NE-Sicily and western Calabria, we find that this longer wavelength signal can be presently super-imposed on the observed velocity gradients in NE-Sicily and Calabria. The inferred slip-rate on the Messina Fault is significantly impacted by elastic strain from the subduction thrust. By varying the locking of the subduction thrust fault, in fact, the Messina Fault slip-rate varies from 0 to 9 mm/yr.
    Description: Published
    Description: 347-360
    Description: 1.9. Rete GPS nazionale
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Messina Straits ; Global Positioning System ; strain accumulation ; plate kinematics ; dislocation modeling ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 14
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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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  • 15
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    Extreme methane deuterium, nitrogen and helium enrichment in natural gas from the Homorod seep (Romania) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Methane (CH4) in terrestrial environments, whether microbial, thermogenic, or abiogenic, exhibits a large variance in C and H stable isotope ratios due to primary processes of formation. Isotopic variability can be broadened through secondary, post-genetic processes, such as mixing and isotopic fractionation by oxidation. The highest and lowest 13C and 2H (or D, deuterium) concentrations in CH4 found in various geologic environments to date, are defined as “natural” terrestrial extremes. We have discovered a new extreme in a natural gas seep with values of deuterium concentrations, δDCH4, up to+124‰that far exceed those reported for any terrestrial gas. The gas, seeping from the small Homorod mud volcano in Transylvania (Romania), also has extremely high concentrations of nitrogen (N92 vol.%) and helium (up to 1.4 vol.%). Carbon isotopes in CH4, C2H6 and CO2, and nitrogen isotopes in N2 indicate a primary organic sedimentary origin for the gas (a minor mantle component is suggested by the 3He/4He ratio, R/Ra~0.39). Both thermogenic gas formation modeling and Rayleigh fractionation modeling suggest that the extreme deuterium enrichment could be explained by an oxidation process characterised by a δDCH4 and δ13CCH4 enrichment ratio (ΔH/ΔC) of about 20, and may be accounted for by abiogenic oxidation mediated by metal oxides. All favourable conditions for such a process exist in the Homorod area, where increased heat flow during Pliocene–Quaternary volcanism may have played a key role. Finally we observed rapid variations (within 1 h) in C and H isotope ratios of CH4, and in the H2S concentrations which are likely caused by mixing of the deep oxidized CH4–N2–H2S–He rich gas with a microbial methane generated in the mud pool of one of the seeps. We hypothesize that the unusual features of Homorod gas can be the result of a rare combination of factors induced by the proximity of sedimentary organic matter, mafic, metal-rich volcanic rocks and salt diapirs,leading to the following processes: a) primary thermogenic generation of gas at temperatures between 130 and 175 °C; b) secondary alteration through abiogenic oxidation, likely triggered by the Neogene–Quaternary volcanism of the eastern Transylvanian margin; and c) mixing at the surface with microbial methane that formed through fermentation in the mud volcano water pool. The Homorod gas seep is a rare example that demonstrates how post-genetic processes can produce extreme gas isotope signatures (thus far only theorized), and that extremely positive δDCH4 values cannot be used to unambiguously distinguish between biotic and abiotic origin.
    Description: Published
    Description: 89-96
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane ; Deuterium ; Nitrogen ; Helium ; Seep ; Mud volcano ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 16
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    Abiotic methane flux from the Chimaera seep and Tekirova ophiolites (Turkey): Understanding gas exhalation from low temperature serpentinization and implications for Mars (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The emission of abiotic methane (CH4) into the atmosphere from low temperature serpentinization in ophiolitic rocks is documented to date only in four countries, the Philippines, Oman, New Zealand, and Turkey. Serpentinization produces large amounts of hydrogen (H2) which in theory may react with CO2 or CO to form hydrocarbons (Fischer–Tropsch Type synthesis, FTT). Similar mechanisms have been invoked to explain the CH4 detected on Mars, so that understanding flux and exhalation modality of ophiolitic gas on Earth may contribute to decipher the potential degassing on Mars. This work reports the first direct measurements of gas (CH4, CO2) flux ever done on onshore ophiolites with present-day serpentinization. We investigated the Tekirova ophiolites at Çirali, in Turkey, hosting the Chimaera seep, a system of gas vents issuing from fractures in a 5000 m2 wide ophiolite outcrop. At this site at least 150–190 t of CH4 is annually released into the atmosphere. The molecular and isotopic compositions of C1–C5 alkanes, CO2, and N2 combined with source rock maturity data and thermogenic gas formation modelling suggested a dominant abiotic component (~80– 90%) mixed with thermogenic gas. Abiotic H2-rich gas is likely formed at temperatures below 50 °C, suggested by the low deuterium/hydrogen isotopic ratio of H2 (δDH2: −720‰), consistent with the low geothermal gradient of the area. Abiotic gas synthesis must be very fast and effective in continuously producing an amount of gas equivalent to the long-lasting (N2 millennia) emission of N100 t CH4 yr−1, otherwise pressurised gas accumulation must exist. Over the same ophiolitic formation, 3 km away from Chimaera, we detected an invisible microseepage of abiotic CH4 with fluxes from 0.07 to 1 g m−2 d−1. On Mars similar fluxes could be able to sustain the CH4 plume apparently recognised in the Northern Summer 2003 (104 or 105 t yr−1) over the wide olivine bedrock and outcrops of hydrated silicates in the Syrtis Major and Nili Fossae; just one seep like Chimaera or, more realistically, a weak, spatially sporadic microseepage, would be sufficient to maintain the atmospheric CH4 level on Mars.
    Description: Published
    Description: 96-104
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: abiotic methane ; seepage ; serpentinization ; ophiolites ; Mars ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 17
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    Fluid origin, gas fluxes and plumbing system in the sediment-hosted Salton Sea Geothermal System (California, USA) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Salton Sea Geothermal System (California) is an easily accessible setting for investigating the interactions of biotic and abiogenic geochemical processes in sediment-hosted hydrothermal systems. We present new temperature data and the molecular and isotopic composition of fluids seeping at the Davis-Schrimpf seep field during 2003–2008. Additionally, we show the first flux data for CO2 and CH4 released throughout the field from focused vents and diffuse soil degassing. The emitted gases are dominated by CO2 (~98%) and CH4 (~1.5%). By combining δ13CCO2 (as low as −5.4‰) and δ13CCH4 (−32‰to−17.6‰) with 3He/4He (R/RaN6) and δDCH4 values (−216‰to−150‰), we suggest, in contrast to previous studies, that CO2 may have a significant Sub-Continental Mantle source, with minimal crustal contamination, and CH4 seems to be a mixture of high temperature pyrolitic (thermogenic) and abiogenic gas. Water seeps show that δD and δ18O increase proportionally with salinity (Total Dissolved Solids in g/L) ranging from 1–3 g/L (gryphons) to 145 g/L (hypersaline pools). In agreement with elemental analyses, the isotopic composition of the waters indicate a meteoric origin, modified by surface evaporation, with little or no evidence of deep fossil or magmatic components. Very high Cl/Br (N3,000) measured at many seeping waters suggests that increased salinities result from dissolution of halite crusts near the seep sites. Gas flux measurements from 91 vents (pools and gryphons) give a conservative estimate of ~2,100 kg of CO2 and 11.5 kg of CH4 emitted per day. In addition soil degassing measured at 81 stations (20x20 m grid over 51,000 m2) revealed that 7,310 kg/d CO2 and 33 kg/d CH4 are pervasively released to the atmosphere. These results emphasise that diffuse gas emission from soil can be dominant (~75%) even in hydrothermal systems with large and vigorous gas venting. Sediment-hosted hydrothermal systems may represent an intermediate class of geologic methane sources for the atmosphere, with emission factors lower than those of sedimentary seepage in petroleum basins but higher than those of traditional geothermal-volcanic systems; on a global scale they may significantly contribute to the atmospheric methane budget.
    Description: Published
    Description: 67-83
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Salton Sea Geothermal System ; hydrothermal seeps ; gas and water geochemistry ; flux measurements ; mantle ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 18
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    A model for seismicity rates observed during the 1982–1984 unrest at Campi Flegrei caldera (Italy) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We consider the space–time distribution of seismicity during the 1982–1984 unrest at Campi Flegrei caldera (Italy) where a correlation between seismicity and rate of ground uplift was suggested. In order to investigate this effect, we present a model based on stress transfer from the deformation source responsible for the unrest to potential faults. We compute static stress changes caused by an inflating source in a layered half-space. Stress changes are evaluated on optimally oriented planes for shear failure, assuming a regional stress with horizontal extensional axis trending NNE-SSW. The inflating source is modeled as inferred by previous studies from inversion of geodetic data with the same crustal model here assumed. The magnitude of the regional stress is constrained by imposing an initial condition of “close to failure” to potential faults. The resulting spatial distribution of stress changes is in agreement with observations. We assume that the temporal evolution of ground displacement, observed by a tide-gauge at Pozzuoli, was due mainly to time dependent processes occurring at the inflating source. We approximate this time dependence in piecewise-linear way and we attribute it to each component of average stress-change in the region interested by the observed seismicity. Then we evaluate the effect of a time dependent stressing rate on seismicity, by following the approach indicated by Dieterich (1994) on the basis of the rate- and state-dependent rheology of faults. The seismicity rate history resulting from our model is in general agreement with data during the period 1982– 1984 for reasonable values of unconstrained model-parameters, the initial value of the direct effect of friction and the reference shear stressing rate. In particular, this application shows that a decreasing stressing-rate is effective in damping the seismicity rate.
    Description: Published
    Description: 287-298
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Triggered seismicity ; Volcanic tremor ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 19
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    Societal need for improved understanding of climate change, anthropogenic impacts, and geo-hazard warning drive development of ocean observatories in European Seas (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Society’s needs for a network of in situ ocean observing systems cross many areas of earth and marine science. Here we review the science themes that benefit from data supplied from ocean observatories. Understanding from existing studies is fragmented to the extent that it lacks the coherent long-term monitoring needed to address questions at the scales essential to understand climate change and improve geo-hazard early warning. Data sets from the deep sea are particularly rare with long-term data available from only a few locations worldwide. These science areas have impacts on societal health and well-being and our awareness of ocean function in a shifting climate. Substantial efforts are underway to realise a network of open-ocean observatories around European Seas that will operate over multiple decades. Some systems are already collecting high-resolution data from surface, water column, seafloor, and sub-seafloor sensors linked to shore by satellite or cable connection in real or near-real time, along with samples and other data collected in a delayed mode. We expect that such observatories will contribute to answering major ocean science questions including: How can monitoring of factors such as seismic activity, pore fluid chemistry and pressure, and gas hydrate stability improve seismic, slope failure, and tsunami warning? What aspects of physical oceanography, biogeochemical cycling, and ecosystems will be most sensitive to climatic and anthropogenic change? What are natural versus anthropogenic changes? Most fundamentally, how are marine processes that occur at differing scales related? The development of ocean observatories provides a substantial opportunity for ocean science to evolve in Europe. Here we also describe some basic attributes of network design. Observatory networks provide the means to coordinate and integrate the collection of standardised data capable of bridging measurement scales across a dispersed area in European Seas adding needed certainty to estimates of future oceanic conditions. Observatory data can be analysed along with other data such as those from satellites, drifting floats, autonomous underwater vehicles, model analysis, and the known distribution and abundances of marine fauna in order to address some of the questions posed above. Standardised methods for information management are also becoming established to ensure better accessibility and traceability of these data sets and ultimately to increase their use for societal benefit. The connection of ocean observatory effort into larger frameworks including the Global Earth Observation System of Systems (GEOSS) and the Global Monitoring of Environment and Security (GMES) is integral to its success. It is in a greater integrated framework that the full potential of the component systems will be realised.
    Description: Published
    Description: 1-33
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: Seafloor and water columnobservatories ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate ; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions ; 03. Hydrosphere::03.01. General::03.01.08. Instruments and techniques ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.03. Physical::03.03.02. General circulation ; 03. Hydrosphere::03.03. Physical::03.03.03. Interannual-to-decadal ocean variability ; 03. Hydrosphere::03.03. Physical::03.03.05. Instruments and techniques ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.04. Geology::04.04.04. Marine 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::04.05. Geomagnetism::04.05.05. Main geomagnetic field ; 04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.03. Heat generation and transport ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 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::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.08. Risk::05.08.01. Environmental risk ; 05. General::05.08. Risk::05.08.02. Hydrogeological risk
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  • 20
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    New evidence of mantle heterogeneity beneath the Hyblean Plateau (southeast Sicily, Italy) as inferred from noble gases and geochemistry of ultramafic xenoliths (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We analyzed major and trace elements, Sr and Nd isotopes in ultramafic xenoliths in Miocenic age Hyblean diatremes, along with noble gases of CO2-rich fluid inclusions hosted in the same products. The xenoliths consist of peridotites and pyroxenites, which are considered to be derived from the upper mantle. Although the mineral assemblage of peridotites and their whole-rock abundance of major elements (e.g., Al2O3 = 0.8–1.5 wt.%, TiO2 = 0.03–0.08 wt.%) suggest a residual character of the mantle, a moderate enrichment in some incompatible elements (e.g., LaN/YbN = 9–14) highlights the presence of cryptic metasomatic events. In this context a deep silicate liquid is considered the metasomatizing agent, which is consistent with the occurrence of pyroxenites as veins in peridotites. Both the Zr/Nb and 143Nd/144Nd ratios of the investigated samples reveal two distinct compositional groups: (1) peridotites with Zr/Nb ≈ 4 and 143Nd/144Nd ≈ 0.5129, and (2) pyroxenites with Zr/Nb ≈ 20 and 143Nd/144Nd ≈ 0.5130. The results of noble-gas analyses also highlight the difference between the peridotite and pyroxenite domains. Indeed, the 3He/4He and 4He/40Ar* ratios measured in the fluid inclusions of peridotites (respectively 7.0–7.4 ± 0.1 Ra and 0.5–8.2, where Ra is the atmospheric 3He/4He ratio of 1.38 × 10− 6) were on average lower than those for the pyroxenites (respectively 7.2–7.6 Ra and 0.62–15). This mantle heterogeneity is interpreted as resulting from a mixing between two end-members: (1) a peridotitic layer with 3He/4He ≈ 7 Ra and 4He/40Ar* ≈ 0.4, which is lower than the typical mantle ratio (~ 1–4) probably due to melt extraction events, and (2) metasomatizing mafic silicate melts that gave rise to pyroxenites characterized by 3He/4He ≈ 7.6 Ra, with a variable 4He/40Ar* due to degassing processes connected with the ascent of magma at different levels in the peridotite wall rock. The complete geochemical data set also suggests two distinct mantle sources for the xenolithic groups highlighted above: (1) a HIMU (high-μ)-type source for the peridotites and (2) a DM (depleted mantle)-type source for the pyroxenites.
    Description: Published
    Description: 70-81
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: restricted
    Keywords: noble gases ; mantle ; xenoliths ; fluid inclusions ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 21
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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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  • 22
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    Helium and argon isotopic compositions of mantle xenoliths from Tallante and Calatrava, Spain. (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We have analyzed by single-step crushing helium and argon isotopes in olivine and orthopyroxene from mantle xenoliths of Calatrava (CLV) in central Spain and Tallante (TL) in southeast Spain. The investigation focused on carefully selected samples previously characterized in terms of major and trace elements on both bulk rock and constituent minerals, and Sr and Nd isotopes on clinopyroxene separates. Six analyses were performed on protogranular spinel lherzolites from CLV, and 17 were performed on spinel harzburgites, lherzolites, and orthopyroxenites from TL. The 40Ar/36Ar ratio was between 296 and 622, indicating atmospheric contamination, which probably occurred during exposure to the surface. The helium-isotope ratio (3He/4He) ranged between 3.6 and 6.5 Ra in CLV samples and between 1.4 and 5.7 Ra in TL samples. There was a positive correlation between the 3He/4He and 4He/40Ar* ratios, possibly reflecting diffusive fractionation between 3He, 4He, and 40Ar within mantle sections interacting with ascending melts. However, the difference between the maximum 3He/4He ratios measured in CLV and TL appears to be related to significant differences in the metasomatic melts that affected the two sectors of the lithospheric mantle. In agreement with the findings of previous studies, the helium isotopes at CLV are compatible with metasomatism due to ascending HIMU-type asthenospheric melts. In contrast, the lower 3He/4He values recorded at TL suggest subduction-related metasomatic components that are possibly related to the Cenozoic subduction of the Betic system. Such event plausibly introduced crust-derived fluids that metasomatized the mantle wedge, slightly decreasing its 3He/4He value. Noble gases appear decoupled from other elements during these mantle processes, since comparatively low 3He/4He values have been recorded also in samples that are relatively unmetasomatized in terms of incompatible lithophile elements. We hypothesize a role for volatile-dominated, CO2-rich fluids progressively decoupling from the ascending metasomatic melts and migrating in the surrounding peridotite matrix to form a diffuse aureola enriched in noble gases.
    Description: Published
    Description: 18-26
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: noble gas ; xenoliths ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 23
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    Diffuse hydrothermal methane output and evidence of methanotrophic activity within the soils at Sousaki (Greece) (2011)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2017-04-04
    Description: Methane soil flux measurements have been made in 38 sites at the geothermal system of Sousaki (Greece) with the closed chamber method. Fluxes range from –47.6 to 29,150 mg m-2 d-1 and the diffuse CH4 output of the system has been estimated at 19 t a-1. Contemporaneous CO2 flux measurements showed a moderate positive correlation between CO2 and CH4 fluxes. Comparison of the CO2/CH4 soil flux ratios with the CO2/CH4 ratio of the gases of the main gas manifestations provided evidence for methanotrophic activity within the soil. Laboratory CH4 consumption experiments confirmed the presence of methanotrophic microorganisms in soil samples collected at Sousaki. Consumption was generally in the range from –4.9 to –38.9 pmolCH4 h-1 g-1 but could sometimes reach extremely high values (–33,000 pmolCH4 h-1 g-1.). These results are consistent with recent studies on other geothermal systems that revealed the existence of thermoacidophilic bacteria exerting methanotrophic activity in hot, acid soils, thereby reducing methane emissions to the atmosphere.
    Description: Published
    Description: 97–107
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Sousaki ; accumulation chamber ; soil degassing ; hydrothermal systems ; methane output ; methanotrophic activity ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 24
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    Gas seepage from Tokamachi mud volcanoes, onshore Niigata Basin (Japan): Origin, post-genetic alterations and CH4–CO2 fluxes (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Methane and CO2 emissions from the two most active mud volcanoes in central Japan, Murono and Kamou (Tokamachi City, Niigata Basin), were measured in from both craters or vents (macro-seepage) and invisible exhalation from the soil (mini- and microseepage). Molecular and isotopic compositions of the released gases were also determined. Gas is thermogenic (d13CCH4 from 32.9‰ to 36.2‰), likely associated with oil, and enrichments of 13C in CO2 (d13CCO2 up to +28.3‰) and propane (d13CC3H8 up to 8.6‰) suggest subsurface petroleum biodegradation. Gas source and post-genetic alteration processes did not change from 2004 to 2010. Methane flux ranged within the orders of magnitude of 101–104 gmˉ2 dˉ1 in macro-seeps, and up to 446 g mˉ2 dˉ1 from diffuse seepage. Positive CH4 fluxes from dry soil were widespread throughout the investigated areas. Total CH4 emission from Murono and Kamou were estimated to be at least 20 and 3.7 ton aˉ1, respectively, of which more than half was from invisible seepage surrounding the mud volcano vents. At the macro-seeps, CO2 fluxes were directly proportional to CH4 fluxes, and the volumetric ratios between CH4 flux and CO2 flux were similar to the compositional CH4/CO2 volume ratio. Macro-seep flux data, in addition to those of other 13 mud volcanoes, supported the hypothesis that molecular fractionation (increase of the ‘‘Bernard ratio’’ C1/(C2 + C3)) is inversely proportional to gas migration fluxes. The CH4 ‘‘emission factor’’ (total measured output divided by investigated seepage area) was similar to that derived in other mud volcanoes of the same size and activity. The updated global ‘‘emission-factor’’ data-set, now including 27 mud volcanoes from different countries, suggests that previous estimates of global CH4 emission from mud volcanoes may be significantly underestimated.
    Description: Published
    Description: 348-359
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Methane ; natural gas ; mud volcanoes ; seepage ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 25
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    Geochemical evidence for and characterization of CO2 rich gas sources in the epicentral area of the Abruzzo 2009 earthquakes (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We describe the results of a detailed hydrogeochemical campaign on the groundwater circulating in two regional aquifers located in the area of the Abruzzo 2009 earthquakes. The influx of deeply derived CO2 rich gases into the two aquifers is highlighted by the 13C isotopic composition of dissolved carbon species. The source of the gas is roughly localised beneath the epicentral area of the earthquakes where the presence of sources of fluids under high pressure is suggested by seismological investigations. The carbon isotopic-mass balance of the aquifers indicates that the amount of the deep CO2 dissolved and transported by the groundwaters is ~530 t/day. The chemical and isotopic composition of the gas entering the aquifers, named Abruzzo gas, has been derived by comparing the data measured in the springs with the results of a gas–water– rock reaction model, that simulates the evolution of the chemical and isotopic composition of groundwater affected by the input of a deeply-derived CO2 rich gas phase. The composition of Abruzzo gas is compared to that of 40 large gas emissions located in central Italy. The gas becomes progressively richer in radiogenic elements (4He and 40Ar) and in N2, from the volcanic complexes in the west to the Apennines in the east. The Abruzzo gas, in agreement with its location, well matches the composition of the gases emitted in the pre- Apennine region. These geochemical features, consistent with the structural setting of the region, indicate increasing residence times of the gas in the crust moving from west to east. In particular we suggest that the strong increase in radiogenic crustal gases reflects the occurrence of deep traps where the gas is stored at high pressures for a long time and that such high pressure gas pockets play a major role in the generation of Apennine earthquakes.
    Description: Published
    Description: 389–398
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: carbon dioxide ; Abruzzo earthquakes ; carbon isotopes ; helium isotopes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
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  • 26
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    Seismotectonic of Southern Apennines from recent passive seismic experiments (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We used data of local earthquakes collected during two recent passive seismic experiments carried out in southern Italy in order to study the seismotectonic setting of the Lucanian Apennine and the surrounding areas. Based on continuous recordings of the temporary stations we extracted over 15,600 waveforms, which were hand-picked along with those recorded by the permanent stations of the Italian national seismic network obtaining a dense, high-quality dataset of P- and S-arrival times. We examined the seismicity occurring in the period 2001–2008 by relocating 566 out of 1047 recorded events with magnitudes ML ≥1.5 and computing 162 fault-plane solutions. Earthquakes were relocated using a minimum one-dimensional velocity model previously obtained for the region and a Vp/Vs ratio of 1.83. Background seismicity is concentrated within the upper crust (between 5 and 20km of depth) and it is mostly clustered along the Lucanian Apennine chain axis. A significant feature extracted from this study relates to the two E–W trending clusters located in the Potentino and in the Abriola–Pietrapertosa sector (central Lucania region). Hypocentral depths in both clusters are slightly deeper than those observed beneath the Lucanian Apennine. We suggest that these two seismic features are representative of the transition from the inner portion of the chain to the external margin characterized by dextral strike-slip kinematics. In the easternmost part of the study area, below the Bradano foredeep and the Apulia foreland, seismicity is generally deeper and more scattered. The sparse seismicity localized in the Sibari Plain, in the offshore area along the northeastern Calabrian coast and in the Taranto Gulf is also investigated thanks to the new recordings. This seismicity shows hypocenters between 12 and 20km of depth below the Sibari Plain and is deeper (foci between 10 and 35km of depth) in the offshore area of the Taranto Gulf. 102 well-constrained fault-plane solutions, showing predominantly normal and strike-slip character with tensional axes (T-axes) generally NE oriented, were selected for the stress tensor analysis. We investigated stress field orientation inverting focal mechanism belonging to the Lucanian Apennine and the Pollino Range, both areas characterized by a more concentrated background seismicity.
    Description: Published
    Description: 110-124
    Description: 3.2. Tettonica attiva
    Description: 5.7. Consulenze in favore di istituzioni nazionali e attività nell'ambito di trattati internazionali
    Description: JCR Journal
    Description: restricted
    Keywords: Background seismicity ; Passive seismic experiments ; Southern Apennines ; Apulia foreland ; Stress field ; Seismotectonic ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 27
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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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  • 28
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    Slope instability induced by volcano-tectonics as an additional source of hazard in active volcanic areas: the case of Ischia island (Italy) (2011)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: Ischia is an active volcanic island in the Gulf of Naples whose history has been dominated by a calderaforming eruption (ca. 55 ka) and resurgence phenomena that have affected the caldera floor and generated a net uplift of about 900 m since 33 ka. The results of new geomorphological, stratigraphical and textural investigations of the products of gravitational movements triggered by volcano-tectonic events have been combined with the information arising from a reinterpretation of historical chronicles on natural phenomena such as earthquakes, ground deformation, gravitational movements and volcanic eruptions. The combined interpretation of all these data shows that gravitational movements, coeval to volcanic activity and uplift events related to the long-lasting resurgence, have affected the highly fractured marginal portions of the most uplifted Mt. Epomeo blocks. Such movements, mostly occurring since 3 ka, include debris avalanches; large debris flows (lahars); smaller mass movements (rock falls, slumps, debris and rock slides, and small debris flows); and deep-seated gravitational slope deformation. The occurrence of submarine deposits linked with subaerial deposits of the most voluminous mass movements clearly shows that the debris avalanches impacted on the sea. The obtained results corroborate the hypothesis that the behaviour of the Ischia volcano is based on an intimate interplay among magmatism, resurgence dynamics, fault generation, seismicity, slope oversteepening and instability, and eruptions. They also highlight that volcano-tectonically triggered mass movements are a potentially hazardous phenomena that have to be taken into account in any attempt to assess volcanic and related hazards at Ischia. Furthermore, the largest mass movements could also flow into the sea, generating tsunami waves that could impact on the island’s coast as well as on the neighbouring and densely inhabited coast of the Neapolitan area.
    Description: Published
    Description: 79-106
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Ischia . ; Caldera resurgence ; Slope instability ; Debris avalanche ; Lahar ; Volcanic and related hazards ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 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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  • 29
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    Insights into explosive activity at closely-spaced eruptive vents using infrasound signals: Example of Mt. Etna 2008 eruption (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: On 13 May 2008 an eruptive fissure opened on Mount Etna's eastern flank feeding both explosive activity and lava effusion from multiple vents for about 14 months. During the investigated May-September 2008 eruptive period, infrasound recordings from a 4 station-sparse network allowed tracking of the explosive activity in terms of location and dynamics. In order to focus on activity from the eruptive fissure, the infrasonic events generated by the summit craters were selected by using both spectral features and time delays between pairs of stations and excluded from our analysis. Then, to accurately locate events from the fissure, we used a composite method, based on the semblance and brightness functions. This enabled the study of the co-existence of more than one infrasound source and/or its migration along the eruptive fissure. Hence, results permitted us to discriminate the number of active vents and their location along the fissure even when, due to poor weather conditions, it was not possible to access the vents or carry out direct observations. The eruptive activity was characterised by variations in the number of active vents according to the overall intensity of the eruptive event. Variability of the infrasound waveforms highlighted either that distinct vents produced signals with different waveforms, or that single vents generated different events during distinct periods of time, or finally both the previous phenomena. We applied the strombolian bubble vibration model to model waveform differences and attributed the signal variations to bubble radius changes.
    Description: Published
    Description: 1-11
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; Infrasound ; Infrasonic source location ; explosive activity ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 30
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    Graphical interactive generation of gravity and magnetic fields (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper presents a MATLAB®- based geopotential field generator called GamField that constructs and visualizes subsurface sources in 3-D space and computes their gravity and magnetic effects. GamField also computes anomaly gradients and remanent magnetization effects. The user inputs Cartesian prisms along with their physical properties to fabricate subsurface sources. Examples illustrating the utility of GamField for synthetic anomaly generation of gravity and magnetic fields are shown. ftp://ftp.ingv.it/pub/alessandro.pignatelli/Pignatelli
    Description: Published
    Description: 567–572
    Description: 3.4. Geomagnetismo
    Description: 3.8. Geofisica per l'ambiente
    Description: 5.7. Consulenze in favore di istituzioni nazionali e attività nell'ambito di trattati internazionali
    Description: JCR Journal
    Description: restricted
    Keywords: Gravity anomalycomputation ; Magnetic anomalycomputation ; MATLAB ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
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  • 31
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    Atmospheric sources and sinks of volcanogenic elements in a basaltic volcano (Etna, Italy) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This study reports on the first quantitative assessment of the geochemical cycling of volcanogenic elements, from their atmospheric release to their deposition back to the ground. Etna’s emissions and atmospheric depositions were characterised for more than 2 years, providing data on major and trace element abundance in both volcanic aerosols and bulk depositions. Volcanic aerosols were collected from 2004 to 2007, at the summit vents by conventional filtration techniques. Precipitation was collected, from 2006 to 2007, in five rain gauges, at various altitudes around the summit craters. Analytical results for volcanic aerosols showed that the dominant anions were S, Cl, and F, and that the most abundant metals were K, Ca, Mg, Al, Fe, and Ti (1.5–50 lg m 3). Minor and trace element concentrations ranged from about 0.001 to 1 lg m 3. From such analysis, we derived an aerosol mass flux ranging from 3000 to 8000 t a 1. Most analysed elements had higher concentrations close to the emission vent, confirming the prevailing volcanic contribution to bulk deposition. Calculated deposition rates were integrated over the whole Etna area, to provide a first estimate of the total deposition fluxes for several major and trace elements. These calculated deposition fluxes ranged from 20 to 80 t a 1 (Al, Fe, Si) to 0.01–0.1 t a 1 (Bi, Cs, Sc, Th, Tl, and U). Comparison between volcanic emissions and atmospheric deposition showed that the amount of trace elements scavenged from the plume in the surrounding of the volcano ranged from 0.1% to 1% for volatile elements such as As, Bi, Cd, Cs, Cu, Tl, and from 1% to 5% for refractory elements such as Al, Ba, Co, Fe, Ti, Th, U, and V. Consequently, more than 90% of volcanogenic trace elements were dispersed further away, and may cause a regional scale impact. Such a large difference between deposition and emission fluxes at Mt. Etna pointed to relatively high stability and long residence time of aerosols in the plume.
    Description: Published
    Description: 7401-7425
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: trace elements ; volcanic plume chemistry ; bulk deposition ; Etna ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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  • 32
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    Graphical interactive generation of gravity and magnetic fields (2011)
    Elsevier
    Details
    Publication Date: 2020-02-24
    Description: This paper presents a MATLAB®- based geopotential field generator called GamField that constructs and visualizes subsurface sources in 3-D space and computes their gravity and magnetic effects. GamField also computes anomaly gradients and remanent magnetization effects. The user inputs Cartesian prisms along with their physical properties to fabricate subsurface sources. Examples illustrating the utility of GamField for synthetic anomaly generation of gravity and magnetic fields are shown. ftp://ftp.ingv.it/pub/alessandro.pignatelli/Pignatelli
    Description: In press
    Description: 3.4. Geomagnetismo
    Description: 3.8. Geofisica per l'ambiente
    Description: 5.7. Consulenze in favore di istituzioni nazionali e attività nell'ambito di trattati internazionali
    Description: JCR Journal
    Description: restricted
    Keywords: Gravity anomalycomputation ; Magnetic anomalycomputation ; MATLAB ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
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  • 33
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    Laboratory measurements of the physical properties of Triassic Evaporites from Central Italy and correlation with geophysical data (2011)
    Elsevier
    Details
    Publication Date: 2022-04-29
    Description: The Triassic Evaporites (TE) of the Umbria–Marche Apennines, a sedimentary succession made up of a sequence of alternating sulphates (anhydrites and gypsum) and dolostones, represent a key lithology in terms of sealing properties and earthquake triggering. Here we: (1) report laboratory measurements of density, porosity, Vp, Vs, seismic anisotropy and permeability at effective confining pressures from 0 to 100 MPa, conducted on samples of TE collected from both outcrops and boreholes; and (2) attempt to upscale the laboratory results to larger scale geophysical investigation, such as Vp sonic logs, seismic tomography and in situ measurements of pore-fluid pressure. The average laboratory P-wave velocity is 6.0 km/s for dolostones, 4.6 km/s for gypsum–dolostones and 5.8 km/s for anhydrites, at ambient pressure. As effective confining pressure is increased up to 100 MPa, the average P-wave velocity increases to 7.0 km/s for dolostones, 5.3 km/s for gypsum and 6.4 km/s for anhydrites. Vp/Vs ratios appear to be independent of confining pressure, with average values of ∼1.8 to ∼2.2 for sulphates and ∼1.9 to ∼2.2 for dolostones, respectively, for dry and saturated conditions. All samples are characterized by very lowpermeability (10−18m2 to 10−21m2), with the higher values for gypsum–dolostones and fractured dolostones samples. The Vp profiles obtained fromultrasonic laboratory measurementsmatch well the in situ Vp profilesmeasured using sonic logs. In the laboratory, the Vp/Vs ratio increases when pressurized pore fluids are present, in agreement with 4D seismic tomography that relates the increase in Vp/Vs ratio to the migration of fluids during the 1997 Umbria–Marche seismic sequence (Mmax∼6.0) that nucleates within the TE. Our low-permeability values are consistent with deep borehole measurements of high pore-fluid pressure trapped within the Triassic Evaporites.
    Description: Published
    Description: 121-132
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Physical Properties, Laboratory measurements, Triassic Evaporites, Geophysical data ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
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  • 34
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    Quantitative assessment of volcanic ash hazards for health and infrastructure at Mt. Etna (Italy) by numerical simulation (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We performed a quantitative hazard assessment to determine the potential impacts of volcanic tephra fall on human health and infrastructure in the vicinity of Mt. Etna (Italy). Using the numerical model VOL-CALPUFF, we explored the dynamics of long-lasting weak plume eruptions and their effects on the surrounding region. Input data are based on credible estimates of the main parameters characterising the expected events as derived from the historically observed and reconstructed explosive record of Mt. Etna. Monte Carlo techniques are used to capture the effects on estimates of finer ash concentration and total ground deposition due to volcanological uncertainties and meteorological variability. Numerical simulations compute the likelihoods of experiencing critical 10-μm volcanic particle (VP10) concentrations in ambient air and tephra ground deposition at various populated locations around the volcano, including the city of Catania, and at key infrastructure, such as airports and main roads. Results show how the towns and infrastructure on the east side of the volcano are significantly more exposed to ash-related hazards than those on the west side, in accordance with wind statistics. Simulation outcomes also illustrate how, at the sites analysed, the amount of deposited particulate matter is proportional to the intensity (i.e. mass flow rate) of the event whereas predicted values of VP10 concentrations are significantly larger for smaller events due to the reduced dispersal of low altitude plumes. The use of a simple re-mobilization model highlights the fact that particle re-suspension needs to be considered in the estimation of VP10 values. Our findings can be used to inform civil protection agencies responsible for mitigating tephra fall impacts to human health, road transport and aviation safety.
    Description: Published
    Description: 85-96
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic ash ; hazard assessment ; VP10 exposure ; numerical simulation ; VOL-CALPUFF ; Mt. Etna ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
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  • 35
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    Mud volcanoes as potential indicators of regional stress and pressurized layer depth (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Although the use of magmatic volcanoes as indicators of tectonic stress is established, the application of the same principles to mud volcanoes has been overlooked. Here we analyse the onshore Azerbaijan mud volcano province, in the foreland of the Greater Caucasus, and we present the first use of the statistical regional-scale distribution of active mud volcanoes to obtain information about (1) contemporary regional tectonic stress, and (2) the average depth of pressurized source layers. Self-similar clustering suggests that mud is mobilized from a ca. 5 km deep mud-prone layer, and mud volcano strain indicators allow the estimation of a robust present-day direction of regional maximum horizontal stress SH striking ca. 30°E. These results are in excellent agreement with geophysical information about upper crustal structure in the region, and stress data and deformation vectors. We conclude that, besides other fold-and-thrust belts, mud volcano features could be used as a proxy for active stress orientation and source layer determination in inaccessible settings, such as underwater or even the surface of planets where mud volcanoes are considered to be indicators of mobilized fluids.
    Description: Published
    Description: 32-47
    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: Mud volcanoes ; Stress indicators ; Self-similar clustering ; Azerbaijan Greater Caucasus ; Mediterranean Ridge ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 36
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    The Monte Orfano Conglomerate revisited: stratigraphic constraints on Cenozoic tectonic uplift of the Southern Alps (Lombardy, northern Italy) (2011)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: The Monte Orfano Conglomerate (MOC), exposed in the foothills of the Southern Alps (northern Italy), is one of the few outcrops of sediments documenting the Cenozoic tectonic evolution of the Alpine retrowedge. Calcareous nannofossil biostratigraphy allowed us to constrain the upper part of the MOC, formerly attributed to the Early-Middle Miocene in the type-locality, to the earliest Miocene (Neogene part of the NN1 nannofossil zone). A likely latest Oligocene age is therefore suggested for the bulk of the underlying conglomerates, whose base is not exposed. Deposition of the MOC can be placed within the post-collisional tectonic uplift of the Alps, documented in the Lake Como area by the Como Conglomerate (CC) at the base of the Gonfolite Lombarda Group, and supports the correlation with Upper Oligocene clastic sediments cropping out further to the East, in the Lake Garda and in the Veneto-Friuli areas (‘‘molassa’’). The remarkable difference in petrographic composition between the western (CC) and eastern (MOC) clastics deposited in the Alpine retro-foreland basin highlights the synchronous tectonic activity of two structural domains involving different crustal levels. Whilst the bulk of the CC, that straddles the Oligocene/Miocene boundary, records largely the tectonic exhumation of the Alpine axial chain crystalline complexes, the coeval MOC consists of detritus derived from the superficial crustal section (Triassic to Paleogene sedimentary rocks) of the Alpine retrowedge and constrains the onset of the post-collisional deformation phase of the Southern Alps as not younger than the Late Oligocene.
    Description: Published
    Description: 1335-1355
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Southern Alps ; Cenozoic ; Calcareous Nannofossil biostratigraphy ; Clastic Provenance ; Shelf Fan-Delta ; Retroforeland basin ; 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 ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 37
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    Late Quaternary tectonics of the Vallo di Diano basin (southern Apennines, Italy) (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We discuss new data concerning the late Quaternary tectonics of the Vallo di Diano basin, the largest intramontane depression in the southern Apennines chain (Italy). The southern Apennines axis is currently subject to NEeSW extension. Here, active NW-trending normal faults are associated with strong earthquakes (M 〉 6), with average recurrence times 〉1 ka. The Vallo di Diano basin is a half-graben bounded by an extensional fault system VDFS (Vallo di Diano Fault System), featuring three major NW-trending, SW-dipping, w15e17 km long fault segments. Holocene faulting and possible historical seismicity have been documented only for the northern fault segment. No major historical earthquakes can be associated with the other fault segments, and the recent sedimentary and structural evolution of the basin is still poorly constrained. As a consequence, its seismogenetic potential has probably been underestimated. We found evidence of late PleistoceneeHolocene faulting in the relay zone of the central and southern fault segments bordering the basin. Here, late Pleistocene volcaniclastic layers at the apex of an alluvial fan are affected by normal displacements on the order of w1 m. Additionally, in the same area we recognized a previously unreported, 9 km long and 0.5e1.4 km wide set of scarplets (ranging in height between w1 m and 2.5 m) affecting late Pleistoceneelate Holocene alluvial fans. The last deformation is younger than 3 ka BP. Due to the geometric arrangement of these scarplets and the long-term displacement along the Vallo di Diano Fault System, we hypothesize that the central and southern fault segments belong to a w32 km long hard-linked system, capable of generating Mw 〉 6.5 earthquakes. The Vallo di Diano basin is thus bounded to the east for its entire length (w45 km) by an active segmented extensional fault system. Therefore it has to be considered one of the major seismogenic sources in southern Italy.
    Description: Italian Ministry of University and Research (Project FIRB “Research and Development of New Technologies for Protection and Defence of Territory from Natural Risks”, W.P. C3 “Crustal Imaging in Italy”)
    Description: Published
    Description: 3167-3183
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: fault scarp ; relay ramp ; alluvial fan ; Southern Apennines ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 38
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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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  • 39
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    Short residence times for alkaline Vesuvius magmas in a multi-depth supply system: Evidence from geochemical and textural studies (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: It is crucial to understand magma chamber chemico-physical conditions and residence times for high-risk volcanoes because these factors control the occurrence and size of future eruptions. In order to define magmatic pressure–temperature conditions and residence times at the Somma–Vesuvius volcano, we studied the geochemistry and texture of selected past eruptions that are representative of the entire volcanic history. Our petrological model indicates a multi-depth magma chamber composed of a deeper tephritic (350– 400 Mpa) magma layer, which fed Strombolian and effusive eruptions during open-conduit activity, and an upper (200–250 Mpa) phonolitic level, which supplied the high explosive events that followed closedconduit repose time. This upper reservoir matches the inferred transition between sedimentary sequences and metamorphic basement. At this level, the presence of a structural and lithological discontinuity favors magma storage during closed-conduit periods. The prevalent differentiation process was fractional crystallization during the magma cooling associated with upward migration of less dense, evolved liquids. Our results indicate that major steam exolution occurred during the late crystallization stage of phonolites, which accounts for the high Volcanic Explosivity Index (VEI) of eruptions supplied by these melts. Moreover, our phenocryst CSD data reveal the rapid crystallization and differentiation (decades to centuries) of alkaline Somma–Vesuvius magmas. This implies that the 400 km2 partial melting zone detected by tomography studies at 8–10 km depth beneath Vesuvius should consist of differentiated magma that is already capable of generating a large-scale (plinian) explosive event if renewed activity develops out of the present closed-conduit state. Additionally, because our microlite CSD data indicate rapid magma migration from the chamber toward the surface, precursory activity could appear only short time before a major eruption.
    Description: Published
    Description: 133–143
    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: JCR Journal
    Description: reserved
    Keywords: residence time ; phonolite ; Vesuvius ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
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  • 40
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    Methane emissions from Earth’s degassing: Implications for Mars (2011)
    Elsevier
    Details
    Publication Date: 2022-02-16
    Description: The presence of methane on Mars is of great interest, since one possibility for its origin is that it derives from living microbes. However, CH4 in the martian atmosphere also could be attributable to geologic emissions released through pathways similar to those occurring on Earth. Using recent data on methane degassing of the Earth, we have estimated the relative terrestrial contributions of fossil geologic methane vs. modern methane from living methanogens, and have examined the significance that various geologic sources might have for Mars. Geologic degassing includes microbial methane (produced by ancient methanogens), thermogenic methane (from maturation of sedimentary organic matter), and subordinately geothermal and volcanic methane (mainly produced abiogenically). Our analysis suggests that not, vert, similar80% of the “natural” emission to the terrestrial atmosphere originates from modern microbial activity and not, vert, similar20% originates from geologic degassing, for a total CH4 emission of not, vert, similar28.0×107 tonnes year−1. Estimates of methane emission on Mars range from 12.6×101 to 57.0×104 tonnes year−1 and are 3–6 orders of magnitude lower than that estimated for Earth. Nevertheless, the recently detected martian, Northern-Summer-2003 CH4 plume could be compared with methane expulsion from large mud volcanoes or from the integrated emission of a few hundred gas seeps, such as many of those located in Europe, USA, Mid-East or Asia. Methane could also be released by diffuse microseepage from martian soil, even if macro-seeps or mud volcanoes were lacking or inactive. We calculated that a weak microseepage spread over a few tens of km2, as frequently occurs on Earth, may be sufficient to generate the lower estimate of methane emission in the martian atmosphere. At least 65% of Earth’s degassing is provided by kerogen thermogenesis. A similar process may exist on Mars, where kerogen might include abiogenic organics (delivered by meteorites and comets) and remnants of possible, past martian life. The remainder of terrestrial degassed methane is attributed to fossil microbial gas (not, vert, similar25%) and geothermal-volcanic emissions (not, vert, similar10%). Global abiogenic emissions from serpentinization are negligible on Earth, but, on Mars, individual seeps from serpentinization could be significant. Gas discharge from clathrate-permafrost destabilization should also be considered. Finally, we have shown examples of potential degassing pathways on Mars, including mud volcano-like structures, fault and fracture systems, and major volcanic edifices. All these types of structures could provide avenues for extensive gas expulsion, as on Earth. Future investigations of martian methane should be focused on such potential pathways.
    Description: Published
    Description: 182-195
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Mars ; Methane ; Earth’s degassing ; Seepage ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 41
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    The Pomici di Avellino eruption of Somma–Vesuvius (3.9 ka BP). Part II: sedimentology and physical volcanology of pyroclastic density current deposits (2011)
    Springer-Verlag
    Details
    Publication Date: 2021-12-16
    Description: Pyroclastic density currents (PDCs) generated during the Plinian eruption of the Pomici di Avellino (PdA) of Somma–Vesuvius were investigated through field and laboratory studies, which allowed the detailed reconstruction of their eruptive and transportation dynamics and the calculation of key physical parameters of the currents. PDCs were generated during all the three phases that characterised the eruption, with eruptive dynamics driven by both magmatic and phreatomagmatic fragmentation. Flows generated during phases 1 and 2 (EU1 and EU3pf, magmatic fragmentation) have small dispersal areas and affected only part of the volcano slopes. Lithofacies analysis demonstrates that the flow-boundary zones were dominated by granular-flow regimes, which sometimes show transitions to traction regimes. PDCs generated during eruptive phase 3 (EU5, phreatomagmatic fragmentation) were the most voluminous and widespread in the whole of Somma–Vesuvius’ eruptive history, and affected a wide area around the volcano with deposit thicknesses of a few centimetres up to more than 25 km from source. Lithofacies analysis shows that the flowboundary zones of EU5 PDCs were dominated by granular flows and traction regimes. Deposits of EU5 PDC show strong lithofacies variation northwards, from proximally thick, massive to stratified beds towards dominantly alternating beds of coarse and fine ash in distal reaches. The EU5 lithofacies also show strong lateral variability in proximal areas, passing fromthe western and northern to the eastern and southern volcano slopes, where the deposits are stacked beds of massive, accretionary lapilli-bearing fine ash. The sedimentological model developed for the PDCs of the PdA eruption explains these strong lithofacies variations in the light of the volcano’s morphology at the time of the eruption. In particular, the EU5 PDCs survived to pass over the break in slope between the volcano sides and the surrounding volcaniclastic apron–alluvial plain, with development of new flows from the previously suspended load. Pulses were developed within individual currents, leading to stepwise deposition on both the volcano slopes and the surrounding volcaniclastic apron and alluvial plain. Physical parameters including velocity, density and concentration profile with height were calculated for a flow of the phreatomagmatic phase of the eruption by applying a sedimentological method, and the values of the dynamic pressure were derived. Some hazard considerations are summarised on the assumption that, although not very probable, similar PDCs could develop during future eruptions of Somma–Vesuvius
    Description: Published
    Description: 559–577
    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: JCR Journal
    Description: reserved
    Keywords: Pyroclastic density currents ; Pomici diAvellino ; Somma–Vesuvius ; Dynamic pressure ; 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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    The Pomici di Avellino eruption of Somma-Vesuvius (3.9 ka BP). Part I: stratigraphy, compositional variability and eruptive dynamics (2011)
    Springer-Verlag
    Details
    Publication Date: 2021-12-16
    Description: The stratigraphic succession of the Pomici di Avellino Plinian eruption from Somma-Vesuvius has been studied through field and laboratory data in order to reconstruct the eruption dynamics. This eruption is particularly important in the Somma-Vesuvius eruptive history because (1) its vent was offset with respect to the present day Vesuvius cone; (2) it was characterised by a distinct opening phase; (3) breccia-like very proximal fall deposits are preserved close to the vent and (4) the pyroclastic density currents generated during the final phreatomagmatic phase are among the most widespread and voluminous in the entire history of the volcano. The stratigraphic succession is, here, divided into deposits of three main eruptive phases (opening, magmatic Plinian and phreatomagmatic), which contain five eruption units. Short-lived sustained columns occurred twice during the opening phase (Ht of 13 and 21.5 km, respectively) and dispersed thin fall deposits and small pyroclastic density currents onto the volcano slopes. The magmatic Plinian phase produced the main volume of erupted deposits, emplacing white and grey fall deposits which were dispersed to the northeast. Peak column heights reached 23 and 31 km during the withdrawal of the white and the grey magmas, respectively. Only one small pyroclastic density current was emplaced during the main Plinian phase. In contrast, the final phreatomagmatic phase was characterised by extensive generation of pyroclastic density currents, with fallout deposits very subordinate and limited to the volcano slopes. Assessed bulk erupted volumes are 21×106 m3 for the opening phase, 1.3– 1.5 km3 for the main Plinian phase and about 1 km3 for the final phreatomagmatic phase, yielding a total volume of about 2.5 km3. Pumice fragments are porphyritic with sanidine and clinopyroxene as the main mineral phases but also contain peculiar mineral phases like scapolite, nepheline and garnet. Bulk composition varies from phonolite (white magma) to tephri-phonolite (grey magma).
    Description: Published
    Description: 539–558
    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: JCR Journal
    Description: reserved
    Keywords: Avellino eruption ; Somma-Vesuvius ; Stratigraphy ; Eruptive dynamics ; 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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  • 43
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    Carbon dioxide degassing and thermal energy release in the Monte Amiata volcanic-geothermal area (Italy) (2010)
    Elsevier
    Details
    Publication Date: 2021-01-07
    Description: The quaternary volcanic complex of Mount Amiata is located in southern Tuscany (Italy) and represents the most recent manifestation of the Tuscan Magmatic Province. The region is characterised by a large thermal anomaly and by the presence of numerous CO2-rich gas emissions and geothermal features, mainly located at the periphery of the volcanic complex. Two geothermal systems are located, at increasing depths, in the carbonate and metamorphic formations beneath the volcanic complex. The shallow volcanic aquifer is separated from the deep geothermal systems by a low permeability unit (Ligurian Unit). A measured CO2 discharge through soils of 1.8 109 mol a 1 shows that large amounts of CO2 move from the deep reservoir to the surface. A large range in d13CTDIC ( 21.07 to +3.65) characterises the waters circulating in the aquifers of the region and the mass and isotopic balance of TDIC allows distinguishing a discharge of 0.3 109 mol a 1 of deeply sourced CO2 in spring waters. The total natural CO2 discharge (2.1 109 mol a 1) is slightly less than minimum CO2 output estimated by an indirect method (2.8 109 mol a 1), but present-day release of 5.8 109 mol a 1 CO2 from deep geothermal wells may have reduced natural CO2 discharge. The heat transported by groundwater, computed considering the increase in temperature from the infiltration area to the discharge from springs, is of the same order of magnitude, or higher, than the regional conductive heat flow (〉200 mWm 2) and reaches extremely high values (up to 2700mWm 2) in the north-eastern part of the study area. Heat transfer occurs mainly by conductive heating in the volcanic aquifer and by uprising gas and vapor along fault zones and in those areas where low permeability cover is lacking. The comparison of CO2 flux, heat flow and geological setting shows that near surface geology and hydrogeological setting play a central role in determining CO2 degassing and heat transfer patterns.
    Description: Published
    Description: 860–875
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Carbon dioxide degassing ; Monte Amiata ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 44
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    Seasonal cycles of seismic velocity variations detected using coda wave interferometry at Fogo volcano, São Miguel, Azores, during 2003–2004 (2010)
    Elsevier
    Details
    Publication Date: 2020-11-12
    Description: Fogo volcano is an active central volcano, with a lake filled caldera, in the central part of São Miguel Island, Azores, whose current activity is limited to hydrothermal manifestations such as active fumarolic fields, thermal and CO2 cold springs and soil diffuse degassing areas. It is affected by important active tectonic structures, with high seismic activity and practically continuous micro-seismicity. A recurrent feature from the seismicity observed in volcanic regions is the occurrence of clusters of similar earthquakes, whose origin can be attributed to the repeated action of a similar source mechanism at the same focal area. Doublets/multiplets were identified in this study within a catalogue of small magnitude (usually 〈 3) volcano tectonic events recorded in 2003–2004 by a selection of stations around Fogo volcano. All events have been cross-correlated and pairs whose waveforms exhibited a cross-correlation coefficient equal to or higher than 0.9 were analysed using the coda-wave interferometry technique. Subtle velocity variations found between events highlight a seasonal cycle of the velocity patterns, with lower velocity in winter time and higher velocity during summer months. Those results, together with quantitative differences between the same doublets at different stations, exhibit an excellent correlation with rainfall. A seasonal effect can also be broadly seen in the seismicity occurrence, and some of the swarms recorded over the two year period occur during the wettest season or close to episodes of abundant (above average) rainfall. Moreover, temporal and spatial analysis of several swarms highlighted the lack of any mainshock–aftershock sequence and organized migration of the hypocenters. This is suggestive of a very heterogeneous stress field. Vp/Vs is found to be lower than usually observed in volcanic areas, an occurrence likely related to the presence of steamy fluid associated with the geothermal system. Taken together, these observations suggest that pore pressurisation plays a major role in controlling a considerable part of the recorded seismicity. The geothermal fluids around Fogo massif have been identified as derived from meteoric water, which infiltrates through Fogo Lake and the volcano flanks and flows from south to north on the northern flank. All those elements seem to point to a role played by rainfall in triggering seismicity at São Miguel, possibly through pressure changes at depth in response to surface rain and/or an interaction with the geothermal system.
    Description: Published
    Description: 231-246
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: velocity changes ; rainfall ; volcano seismicity ; triggered seismicity ; Azores archipelago ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
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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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 46
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    Astronomical tuning of the La Vedova High Cliff section (Ancona, Italy)—Implications of the Middle Miocene Climate Transition for Mediterranean sapropel formation (2010)
    Elsevier
    Details
    Publication Date: 2021-01-25
    Description: Continuous marine successions covering the Middle Miocene Climate Transition (MMCT; ∼15–13.7 Ma) are scarce and the lack of a high-resolution magnetobiostratigraphic framework hampers the construction of astronomically tuned age models for this time interval. The La Vedova High Cliff section, exposed along the coast of the Cònero Riviera near Ancona (Italy), is one of the few Mediterranean sections covering the critical time interval of the MMCT. Starting from an initial magnetobiostratigraphic age model, a robust astronomical tuning was constructed for the interval between 14.2 and 13.5 Ma, using geochemical element data and time series analysis. A shift in δ18O of bulk sediment towards heavier values occurs between ∼13.92 and 13.78 Ma and could be related to the Mi3b oxygen isotope event, which reflects the rapid expansion of the East Antarctic Ice Sheet in the middle Miocene. The onset of the CM6 carbon excursion is reflected in the bulk record by a rapid increase in δ13C at 13.86 Ma. Our results confirm the proposition that these events coincide with a 405-kyr minimum in eccentricity and a node in obliquity related to the ∼1.2 Myr cycle. From 13.8 Ma onwards, distinct quadruplet cycles containing sapropelitic sediments were deposited. This may suggest a causal connection between the main middle Miocene cooling step and the onset of sapropel formation in the Mediterranean.
    Description: Published
    Description: 249–261
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Middle Miocene ; Mediterranean ; astronomical tuning ; paleomagnetism ; biostratigraphy ; environmental changes ; orbital forcing ; sapropels ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
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    Tornillos at Vulcano: Clues to the dynamics of the hydrothermal system (2010)
    Elsevier
    Details
    Publication Date: 2020-11-12
    Description: The number of tornillo events has recently increased at the Vulcano Island, Italy. While only 15 tornillos were recorded during 2004–2006, 584 events occurred in 2007–2008. They were located just below La Fossa Crater at depths ranging between 0.1 and 1 km b.s.l. During two intervals in 2007–2008 increases in the number of tornillos took place at the same time as temperature and geochemical anomalies were observed. The spectral content of the tornillos, generally characterized by one–two dominant spectral peaks near 6 and 10 Hz, varied over time, with changes also noted in the quality factors. The simplest source mechanism proposed for tornillos is the free eigenvibration of a fluid volume within a crack or a conduit. Based on this model, we propose a causal relationship between the temperature and geochemical anomalies and the increases in numbers of tornillos. As the amount of hydrothermal fluids increases during the anomalies, the upward flux of fluids grows. The consequent changes in the pressure, temperature and dynamics of the system of cracks and conduits result in the generation of tornillos. Based on the fluid-filled crack/conduit model, the shallow depths of the sources and the values of the quality factors, the fluid within the resonant crack/conduit was inferred to be an ash–gas or water droplet–gas mixture. Moreover, the observed variations in the wavefield can be caused by small changes in the location of the source, in the source mechanism, or in the medium in between the source and the seismic station. Finally, another peculiar feature of tornillos is the amplitude modulation that can be explained as a result of a beating phenomenon.
    Description: Published
    Description: 377-393
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Tornillos ; Vulcano Island ; Hydrothermal system ; Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
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    Carbon dioxide diffuse emission from the soil: ten years of observations at Vesuvio and Campi Flegrei (Pozzuoli), and linkages with volcanic activity (2010)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: Carbon dioxide flux from the soil is regularly monitored in selected areas of Vesuvio and Solfatara (Campi Flegrei, Pozzuoli) with the twofold aim of i) monitoring spatial and temporal variations of the degassing process and ii) investigating if the surface phenomena could provide information about the processes occurring at depth. At present, the surveyed areas include 15 fixed points around the rim of Vesuvio and 71 fixed points in the floor of Solfatara crater. Soil CO2 flux has been measured since 1998, at least once a month, in both areas. In addition, two automatic permanent stations, located at Vesuvio and Solfatara, measure the CO2 flux and some environmental parameters that can potentially influence the CO2 diffuse degassing. Series acquired by continuous stations are characterized by an annual periodicity that is related to the typical periodicities of some meteorological parameters. Conversely, series of CO2 flux data arising from periodic measurements over the arrays of Vesuvio and Solfatara are less dependent on external factors such as meteorological parameters, local soil properties (porosity, hydraulic conductivity) and topographic effects (high or low ground). Therefore we argue that the long-term trend of this signal contains the “best” possible representation of the endogenous signal related to the upflow of deep hydrothermal fluids.
    Description: Published
    Description: 103-118
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Carbon dioxide ; Soil diffuse degassing ; Monitoring ; Vesuvio . Campi Flegrei ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 49
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    Tephra layers from Holocene lake sediments of the Sulmona Basin, (2010)
    ELSEVIER
    Details
    Publication Date: 2017-04-04
    Description: We present a new tephrostratigraphic record from the Holocene lake sediments of the Sulmona basin, central Italy. The Holocene succession is represented by whitish calcareous mud that is divided into two units, SUL2 (ca 32 m thick) and SUL1 (ca 8 m thick), for a total thickness of ca 40 m. These units correspond to the youngest two out of six sedimentary cycles recognised in the Sulmona basin that are related to the lake sedimentation since the Middle Pleistocene. Height concordant U series age determinations and additional chronological data constrain the whole Holocene succession to between ca 8000 and 1000 yrs BP. This includes a sedimentary hiatus that separates the SUL2 and SUL1 units, which is roughly dated between 〈2800 and ca 2000 yrs BP. A total of 31 and 6 tephra layers were identified within the SUL2 and SUL1 units, respectively. However, only 28 tephra layers yielded fresh micropumices or glass shards suitable for chemical analyses using a microprobe wavelength dispersive spectrometer. Chronological and compositional constraints suggest that 27 ash layers probably derive from the Mt. Somma-Vesuvius Holocene volcanic activity, and one to the Ischia Island eruption of the Cannavale tephra (2920 _ 450 cal yrs BP). The 27 ash layers compatible with Mt. Somma-Vesuvius activity are clustered in three different time intervals: from ca 2000 to 〉1000; from 3600 to 3100; and from 7600 to 4700 yrs BP. The first, youngest cluster, comprises six layers and correlates with the intense explosive activity of Mt. Somma-Vesuvius that occurred after the prominent AD 79 Pompeii eruption, but only the near-Plinian event of AD 472 has been tentatively recognised. The intermediate cluster (3600– 3100 yrs BP) starts with tephra that chemically and chronologically matches the products from the ‘‘Pomici di Avellino’’ eruption (ca 3800_ 200 yrs BP). This is followed by eight further layers, where the glasses exhibit chemical features that are similar in composition to the products from the so-called ‘‘Protohistoric’’ or AP eruptions; however, only the distal equivalents of three AP events (AP3, AP4 and AP6) are tentatively designated. Finally, the early cluster (7600–4700 yrs BP) comprises 12 layers that contain evidence of a surprising, previously unrecognised, activity of the Mt. Somma-Vesuvius volcano during its supposed period of quiescence, between the major Plinian ‘‘Pomici di Mercato’’ (ca 9000 yrs BP) and ‘‘Pomici di Avellino’’ eruptions. Alternatively, since at present there is no evidence of a similar significant activity in the proximal area of this well-known volcano, a hitherto unknown origin of these tephras cannot be role out. The results of the present study provide new data that enrich our previous knowledge of the Holocene tephrostratigraphy and tephrochronology in central Italy, and a new model for the recent explosive activity of the Peninsular Italy volcanoes and the dispersal of the related pyroclastic deposits.
    Description: Earth and Environment Department of the National Research Council (CNR – TA.Po2.005.005 – Physic and isotopic stratigraphy of Quaternary continental and marine succession)
    Description: Published
    Description: 2710-2733
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: tephrostratigraphy ; Holocene sediments ; Sulmona basin ; Central Italy ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
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  • 50
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    Analysis of small magnitude seismic sequences along the Northern Apennines (Italy) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We analyze the seismicity of a small sector of the Northern Apennines merging data from the Italian seismic bulletin with original data collected by temporary seismic networks. Our attention is focused on the region enclosed between the Apenninic watershed and the Adriatic Sea. This portion of belt is interested by the occurrence of diffuse crustal seismicity and small-to-moderate earthquakes. In this paper we study the five small sequences with mainshock having Mw 〈 4.7 that in the past 15 years hit the area. Our interest is addressed to better understand the relationship between these events and the regional seismotectonic setting in terms of seismicity distribution and stress field. Two regions with different behavior in the seismic release can be distinguished: (i) along the watershed where seismicity is clustered at shallow depths (〈 15 km) and where strong earthquakes occurred in the past, (ii) an eastern portion where the seismicity is distributed across all of the crustal volume, locally reaching depths down to 30 km. The focal mechanism of the seismic sequences shows mainly normal fault kinematics coherent with the regional stress field. Detailed stress field analysis suggests a rotation of the principal stress axis moving from the axial part of the chain toward the Adriatic Sea to the east.
    Description: Published
    Description: 136-144
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Northern Apennines ; Stress field ; Focal mechanisms ; Seismicity ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 51
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    Paleomagnetic investigations on the Pleistocene lacustrine sequence of Piànico-Sèllere (northern Italy) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Piànico-Sèllere is a lacustrine succession from northern Italy that records a sequence of climatic transitions across two Pleistocene glacial stages. The intervening interglacial stage is represented by well-preserved varves with calcitic (summer) and clastic (winter) laminae. There is a tight coupling between climate-driven lithologic changes and magnetic susceptibility variations, and stable paleomagnetic components were retrieved from all investigated lithologies including the largely diamagnetic calcite varves. These components were used to delineate a sequence of magnetic polarity reversals that was interpreted as a record of excursions of the Earth’s magnetic field. Comparison of the magnetostratigraphic results with previously published data allows discussion of two possible models which have generated controversy regarding the age of the Piànico Formation. The data indicates that the Piànico Formation magnetostratigraphy correlates to geomagnetic field excursions across the Brunhes/Matuyama transition, and consequently the Piànico interglacial correlates to marine isotope stage 19. This correlation option is substantially consistent with K-Ar radiometric age estimates recently obtained from a tepha layer interbedded in the Piànico Formation. The alternative option, considering the Piànico interglacial correlative to marine isotope stage 11 within the Brunhes Chron as supported by tephrochronological dating reported in the literature, is not supported by the magnetostratigraphic results.
    Description: Published
    Description: 44-53
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Piànico Formation ; Pleistocene ; magnetostratigraphy ; polarity excursions ; Brunhes Chron ; Southern Alps ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 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::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 52
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    Fluids-Faults relationships over the seismic area of Southern Apennine (Calabria region, Southern Italy): geochemical information from thermal and sulphurous water discharges. (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The first comprehensive geochemical data-set of the fluids circulating over a 14,000 km2-wide seismic-prone area of the Southern Apennines, Calabria Region (Italy), is presented here. The geochemical investigations were carried out with the two-fold aim of constraining the origin and interactions of the circulating fluids and to investigate possible relationships with local faults. We collected 60 samples of both thermal and cold waters, from which we extracted the dissolved gases . The geochemical features of the water samples display different types and degrees of water-rock interactions, irrespective of the outlet temperature. The calculated equilibrium temperatures of the thermal waters (60-160°C) and the low heat flow of the whole study area, are consistent with a heating process due to deep water circulation and rapid upflow through lithospheric structures. The composition of the dissolved gases reveals that crustal-originating gases (N2 and CO2-dominated ) feed all the groundwaters. The 3He/4He ratios of the dissolved helium, in the range of 0.03 to 0.22Rac for the thermal waters and 0.05-0.63Rac for the cold waters (Rac = helium isotope ratio corrected for atmospheric contamination), are mainly the result of a two-component (radiogenic and atmospheric) mixing, although indications of mantle-derived helium are found in some cold waters. As the study area had been hit by 18 of the most destructive earthquakes (magnitude ranging from 5.9 to 7.2) occurring over a 280-year time span (1626-1908) in Southern Apennines, the reported results on the circulating fluids may represent the reference for a better inside knowledge of the fault-fluid relationships and for the development oflong-term geochemical monitoring strategies for the area.
    Description: In press
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Fluids/Fault interactions ; isotope geochemistry ; thermal waters ; dissolved gases ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 53
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    Anomalous fluid emission of a deep borehole in a seismically active area of Northern Apennines (Italy) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Miano borehole of 1047 m depth is located close to the river Parma in the Northern Apennines, Italy. A measuring station is installed to observe the discharge of fluids continuously since November 2004. The upwelling fluid of this artesian well is a mixture of thermal water and methane as main components. In non-seismogenic areas, we would expect a relative constant fluid emission perhaps overlaid with long term variations from that kind of deep reservoirs during the time. However, the continuously record of the fluid emission, in particular the water discharge, the gas flow rate and the water temperature, show periods of stable values interrupted by anomalous periods of fluctuations in the recorded parameters. The anomalous variations of these parameters are of low amplitude in comparison to the total values but significant in their long-term trend. Meteorological influences of rain and barometric pressure were not detected in recorded data probably due to reservoir depth and relatively high reservoir overpressure. Influences due to the ambient temperature after the discharge were evaluated by statistical analysis. We consider that recorded changes in fluid emission parameters can be interpreted as a mixing process of different fluid components in depth by variations in pore pressure as result of seismogenic stress variation. Local seismicity was analyzed in comparison to fluid’s physico-chemical data. The analysis supports the idea of an influence to fluid transport conditions due to geodynamic processes exist. Water temperature data show frequent anomalies probably connected with possible precursory phenomena of local seismic events.
    Description: In press
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Fluids ; Earthquakes ; Continous monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 54
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    Mercury content and speciation in the Phlegrean Fields volcanic complex: Evidence from hydrothermal system and fumaroles (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Mercury is outstanding among the global environmental pollutants of continuing concern. Although degassing of active volcanic areas represents an important natural source of mercury into the atmosphere, still little is known about the amount and behaviour of Hg in volcanic aquifers, especially regarding its chemical speciation. In order to assess the importance of mercury emissions from active volcanoes, thermal waters were sampled in the area surrounding La Solfatara, Pozzuoli bay. This is the most active zone of the Phlegrean Fields complex (coastal area north–west of Naples), with intense hydrothermal activity at present day. Studied groundwaters show total Hg (THg) concentrations range from 56 to 171 ng/l and are lower than the 1000 ng/l threshold value for human health protection fixed by the World Health Organization (WHO, 1993). We also carefully discriminated the different aqueous species of Hg in the collected water samples. Besides, original data on Hg determination in gaseous manifestations at La Solfatara crater are also reported. We measured volcanogenic mercury concentration and Hg/Stot ratio both in the volcanic plume and in fumarolic condensates in order to better constrain Hg reactivity once emitted into the atmosphere. Data on Hg/Stot reveal that there is no significant difference between Hg volcanic composition at the venting source (fumaroles) and in near-vent diluted volcanic plumes (1.6×10−5 and 1.9×10−5, respectively), suggesting that there is limited Hg chemical processing in volcanic fumarole plumes, at least on the timescales of a few seconds investigated here. Combining the mean fumaroles Hg/CO2 mass ratio of about 1.3×10−8 (molar ratio: 2.1×10−9) with the hydrothermal soil diffuse CO2 degassing of the area, the annual Hg flux from La Solfatara is estimated as 7 kg y−1 (0.007 t y−1). Current mercury emission from La Solfatara volcano represents a very small contribution to the estimated global volcanic budget for this element, and the estimated Hg flux is considerably lower than that estimated from open-conduit active basaltic volcanoes.
    Description: Published
    Description: 250–260
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothermal waters ; total mercury ; mercury speciation ; fumaroles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 55
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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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  • 56
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    Magma dynamics of 2007 Stromboli effusive eruption as revealed by high precision location of seismic events. (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Stromboli is considered one of the most active volcanoes in the world, and its persistent but moderate explosive activity is only interrupted by occasional episodes of more vigorous activity accompanied by lava flows. A new effusive eruption began in late February, 2007 and was characterised by intense seismic activity throughout the whole period. The accurate seismic signals analysis showed the presence of families of events with similar waveform signatures (i.e. multiplets) located beneath the crater region. Since traditional location techniques do not allow obtaining reliable hypocentres, our analysis focused on high precision locations of the seismicity, in order to better define the source geometry of the events. Hypocentres, therefore, have been relocated considering two steps: the first, based on a robust probabilistic approach, is used to find the absolute position of the clusters; the second exploits a master-event concept for the relative location of the events. Finally, the shape of the clusters and the temporal migration of the foci were correlated with the eruptive phases. The results show that the occurrence of a cluster of events is related to the opening and closure of a vent opened in the Sciara del Fuoco slope and, in particular, to the intrusion of a dike injected by central conduit in a radial direction, whereas another cluster lies in a narrow vertical volume positioned under the crater area. The geometry of the clusters suggests a source region depicting the shallower feeding system. Overall, the results highlight that the high precision locations method is an efficient and quick tool to obtain a better understanding of the magmatic processes occurring during an ongoing eruption.
    Description: Published
    Description: 405-415
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: eruption ; high precision location ; seismic swarms ; magma dynamics ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 57
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    Microseepage in drylands: Flux and implications in the global atmospheric source/sink budget of methane (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Drylands are considered a net sink for atmospheric methane and a main item of the global inventories of the greenhouse gas budget. It is outlined here, however, that a significant portion of drylands occur over sedimentary basins hosting natural gas and oil reservoirs, where gas migration to the surface takes place, producing positive fluxes of methane into the atmosphere. New field surveys, in different hydrocarbonprone basins, confirm that microseepage, enhanced by faults and fractures in the rocks, overcomes the methanotrophic consumption occurring in dry soil throughout large areas, especially in the winter season. Fluxes of a few units to some tens of mg m−2 day−1 are frequent over oil–gas fields, whose global extent is estimated at 3.5–4.2 million km2; higher fluxes (〉50 mg m−2 day−1) are primarily, but not exclusively, found in basins characterized by macro-seeps. Microseepage may however potentially exist over a wider area (∼8 million km2, i.e. 15% of global drylands), including the Total Petroleum Systems, coal measures and portions of sedimentary basins that have experienced thermogenesis. Based on a relatively large and geographically dispersed data-set (563 measurements) from different hydrocarbon-prone basins in USA and Europe, upscaling suggests that global microseepage emission exceeding 10 Tg year−1 is very likely. Microseepage is then only one component of a wider class of geological sources, including mud volcanoes, seeps, geothermal and marine seepage, which cannot be ignored in the atmospheric methane budget.
    Description: Published
    Description: 265-274
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: microseepage ; methane flux ; soil sink ; drylands ; petroleum ; greenhouse gas ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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    Benthic habitat characterization and distribution from two representative sites of the deep-water SML Coral Province (Mediterranean) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Two sites (MS04 and MS06) from the Santa Maria di Leuca (SML) Coral Province were analyzed by a video and acoustic survey during the National Italian Project Apulian Plateau Bank Ecosystem Study (APLABES). Site MS04 (Atlantis Mound) is characterized by a sub-conical mound, 500 m wide and 25 m high, located at a water depth of about 650 m. Site MS06 (Yellow Chain) comprises several elongated reliefs (NNW–SSE-oriented), up to 25 m high and 500 m in maximum lateral extent, located at a depth of between 490 and 540 m. At both sites, two main mesohabitats (mound and intermound) containing several coral-bearing and -barren macrohabitats were observed in recorded videos and detected in side-scan sonographs. The coral-rich macrohabitats, characterized by densely packed colonies of the scleractinians Madrepora oculata and, secondarily, Lophelia pertusa (M/L), are typically restricted to the mound areas. The mud-dominated ones, almost devoid of M/L colonies, are more common within the intermound mesohabitat. However, on the most extensive mounds, both macrohabitat typologies exist. They are heterogeneously distributed on the mound surface, often showing a clear differentiation along two opposite flanks of the same topographic feature. M/L-rich macrohabitats are preferentially located on top and along the mound northeastern flank, showing a typical step-like distribution, probably reflecting the arrangement of hard substrate outcrops. Along this flank, fan-shaped Madrepora colonies and sponges are often oriented NNW–SSE, implying, together with other evidence, a primary southwestern current flow. The hard-bottom macrohabitats of the southwestern mound flank are generally restricted to sparse exposed, subvertical to overhanging scarps as well as to heterometric boulders located at the scarp base. Their fauna is mainly characterized by small-sized organisms (such as sponges and solitary scleractinians) although m-sized boulders may locally host very large antipatharian colonies (Leiopathes glaberrima). The heterogeneous distribution of the observed benthic macrohabitats seems to be strictly related to the local topography, the main current flow (and consequently larvae/food supply per unit of time), and the substrate typology (hard- vs. soft-bottom).
    Description: Published
    Description: 380-396
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Deep-watercoralmound ; Habitat ; Mediterranean ; Madrepora ; Lophelia ; Visual survey ; Acoustic survey ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 59
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    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40K decays but it can detect other natural (e.g., 238U,232Th) and anthropogenic radio-nuclides (e.g., 137Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.
    Description: In press
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: open
    Keywords: NaI(Tl) sensor ; underwater spectrometer ; marine radioactivity ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 60
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    Astrochronology of the Mediterranean Langhian between 15.29 and 14.17 Ma (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: An integrated high-resolution magnetobiocyclostratigraphy including radioisotopic dating and astronomical tuning is presented for the interval between 15.29 and 14.17 Ma in the marine La Vedova section in northern Italy. The natural remanent magnetization is carried by the iron sulphide greigite and the resultant magnetostratigraphy can be correlated straightforwardly to the interval ranging from C5Bn.2n to C5ADn in the Astronomically Tuned Neogene Time Scale (ATNTS2004). Spectral analysis on high-resolution magnetic susceptibility and geochemical proxy records in the depth domain and, using our magnetobiostratigraphic age model, in the time domain demonstrate that the various scales of cyclicity in the section are related to astronomical climate forcing. Starting from our initial age model, larger-scale cycles were first tuned to eccentricity. This first-order tuning was followed by tuning the basic cycle to precession and boreal summer insolation using inferred phase relations between maxima in Ca/Al, redox-sensitive elements and Ba, and minima in magnetic susceptibility, and maxima in precession and minima in obliquity and boreal summer insolation. Our astronomical ages for reversal boundaries are supported by analysis of sea floor spreading rates and should replace the existing ages in the ATNTS2004 lacking direct astronomical control. Two major steps in the geochemical proxy records, astronomically dated at 15.074 and 14.489 Ma, coincide with abrupt changes in sedimentation rate, and are the result of the combined effect of the ∼400-kyr eccentricity cycle superimposed upon a longer-term climatic or tectonic induced trend.
    Description: Published
    Description: 254–269
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Middle Miocene ; Langhian ; Mediterranean ; astronomical tuning ; palaeomagnetism ; biostratigraphy ; environmental changes ; orbital forcing ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
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  • 61
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    Multiple resolution seismic attenuation imaging at Mt. Vesuvius (2010)
    Elsevier
    Details
    Publication Date: 2019-03-05
    Description: A three-dimensional S wave attenuation tomography of Mt. Vesuvius has been obtained with multiple measurements of coda-normalized S-wave spectra of local small magnitude earthquakes.We used 6609 waveforms, relative to 826 volcano-tectonic earthquakes, located close to the crater axis in a depth range between 1 and 4 km (below the sea level), recorded at seven 3-component digital seismic stations. We adopted a two-point ray-tracing; rays were traced in an high resolution 3-D velocity model. The spatial resolution achieved in the attenuation tomography is comparable with that of the velocity tomography (we resolve 300m side cubic cells). We statistically tested that the results are almost independent from the radiation pattern. We also applied an improvement of the ordinary spectral-slope method to both P- and S-waves, assuming that the differences between the theoretical and the experimental high frequency spectral-slope are only due to the attenuation effects. Consequently we could check the codanormalization method also comparing the S attenuation image with the P attenuation image. The images were obtained inverting the spectral data with a multiple resolution approach. Results have shown the general coincidence of low attenuation with high velocity zones. The joint interpretation of velocity and attenuation images allows us to interpret the low attenuation zone intruding toward the surface until a depth of 500m below the sea level as related to the residual part of solidified magma from the last eruption. In the depth range between −700 and −2300 images are consistent with the presence of multiple acquifer layers. No evidence of magma patches greater than the minimum cell dimension (300m) has been found. A shallow P wave attenuation anomaly (beneath the southern flank of the volcano) is consitent with the presence of gas saturated rocks. The zone characterized by the maximum seismic energy release cohincides with a high attenuation and low velocity volume, interpreted as a cracked medium.
    Description: Published
    Description: 17–32
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Attenuation tomography ; Mt. Vesuvius ; Coda normalization method ; Spectral slope ; Multi resolution inversion ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
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  • 62
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    Deep-sea survey for the detection of methane at the “Santa Maria di Leuca” cold-water coral mounds (Ionian Sea, South Italy) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The “Santa Maria di Leuca” Cold-Water Coral (CWC) province (northern Ionian Sea) was investigated for the first time to detect eventual occurrence of methane anomalies as a possible indication of hydrocarbon seepage stimulating the coral growth. Most coral mounds have developed in correspondence with tectonic scarps and faults, orthogonal to the southern margin and trending NW-SE, which could be potential sites of gas escape. A visual and instrumental inspection was performed by using a new deep-sea probe equipped with video-cameras, sonar, CTD, methane sensors, and a water sampler. Eight areas were explored by 10 surveys, depths ranging from 380 to 1100 m, for a total of more than 26 h of continuous video and instrumental recording. Sediments were also sampled by gravity corers and analysed in laboratory. The images allowed to assess distribution, abundance and geometry of the colonies, most of which are developed on morphological highs often characterised by tectonic scarps. All data indicate however the lack of a significant occurrence of methane, both in seawater and sediments. No direct or indirect expressions of gas seepage were recognised on the seabed. Weak methane anomalies were detected only in seawater at the base of some fault-linked scarps, where more reducing conditions and bacterial methanogenesis are possibly enhanced by less water circulation. The faults are not fluid-bearing as previously suggested by high-resolution geophysical signatures. The development of the coral colonies thus cannot be attributed to seeping fluids, but to a favourable physiographic position with exposure to nutrient-rich currents.
    Description: Published
    Description: 431-440
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Methane ; Corals ; Seepage ; Marine geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 63
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    Geofluids and natural gas in Romania, and the 10th International Conference on Gas Geochemistry (2010)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2017-04-04
    Description: This thematic issue of Geofluids includes 11 papers representing the three main topics discussed in the 10th edition of the International Conference on Gas Geochemistry (ICGG-10): (i) gas in petroleum systems and seepage, (ii) gas in geothermal systems and volcanoes and (iii) gas, seismicity and geohazards. ICGG-10 was held in 2009 in Romania, a country extraordinarily rich in surface gas manifestations, that offers innumerable opportunities for innovative studies on gas geochemistry. We briefly describe the present knowledge on gases occurring both in petroliferous sedimentary basins and geothermal areas of Romania. The 11 contributions of this special issue, which include data from eight countries, are then summarised. Based on these papers and other works presented at the ICGG-10, we find that significant advances in analytical capabilities, data treating and interpretation have led to innovative insights into the origin, distribution and environmental impact of gases migrating to the Earth’s surface. It is increasingly clear, in particular, that gas geochemistry can be more effective for petroleum exploration, volcano-tectonic, geodynamic and environmental studies, if multiparametric studies are performed and the data are interpreted in the geological context.
    Description: Published
    Description: 457-462
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: geothermal gas ; international conference on gas geochemistry ; natural gas ; romania ; seeps ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 64
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    Fault plane orientations of microearthquakes at Mt. Etna from theinversion of P-wave rise times (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: A crucial point in the analysis of tectonic earthquakes occurring in a volcanic area is the inference of the orientation of the structures along which the ruptures occur. These structures represent zones of weakness which could favor the migration of melt toward the surface and the assessment of their geometry is a fundamental step toward efficient evaluation of volcanic risk. We analyzed a high-quality dataset of 171 lowmagnitude, tectonic earthquakes that occurred at Mt. Etna during the 2002–2003 eruption. We applied a recently developed technique aimed at inferring the source parameters (source size, dip and strike fault) and the intrinsic quality factor Qp of P waves from the inversion of rise times. The technique is based on numerically calibrated relationships among the rise time of first P waves and the source parameters for a circular crack rupturing at a constant velocity. For the most of the events the directivity source effect did not allow us to constrain the fault plane orientation. For a subset of 45 events with well constrained focal mechanisms we were able to constrain the “true” fault plane orientation. The level of resolution of the fault planes was assessed through a non linear analysis based on the random deviates technique. The significance of the retrieved fault plane solutions and the fit of the assumed source model to data were assessed through a χ-square test. Most of the retrieved fault plane solutions agree with the geometrical trend of known surface faults. The inferred source parameters and Qp are in agreement with the results of previous studies
    Description: Published
    Description: 247-256
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: rise time ; directivity ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 65
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    High-resolution intra- and interbasinal correlation of the Danian–Selandian transition (Early Paleocene): The Bjala section (Bulgaria) and the Selandian GSSP at Zumaia (Spain) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Danian–Selandian (D–S) boundary has been identified for the first time in the Black Sea coast at Bjala (Bulgaria) based on a new integrated bio-, magneto- and cyclostratigraphic study. Several correlation criteria as established for the basal Selandian GSSP from Zumaia (Basque Basin) are evaluated. Noteworthy, is the almost complete lack of calcareous nannoplankton species Braarudosphaera bigelowi in the Bulgarian sections, a sharp decrease of which was indicated as suitable criteria for defining the D–S boundary as it occurred both at Zumaia and in the classical locations of the North Sea basin. Conversely, the second evolutionary radiation of the calcareous nannofossil genus Fasciculithus together with the occurrence of Fasciculithus tympaniformis that define the NP4/NP5 zonal boundary seem to be reliable criteria to approximate the D–S boundary. In detail, however, the best approach is to integrate biostratigraphic data within a magnetostratigraphic and/or cyclostratigraphic framework. Refinements on the placement of chron C27n at Zumaia and robust bed-by-bed correlation between several Basque sections and Bjala indicates that the D–S boundary is located 30 precession cycles (~630 ky) above C27n. In addition to the precession-related marl–limestone couplets and 100-ky eccentricity bundles recognized in the studied sections, expression of the stable 405-ky long eccentricity allows direct tuning to the astronomical solutions. A correlation of the land-based sections with previously tuned data from ODP Site1262 from the Southern Atlantic is challenged. Our choice is consistent with original tuning at Zumaia but shifts one 100-ky cycle older previous tuning from Site 1262 along the interval above C27n. Under the preferred tuning scheme the D–S boundary can be given an age of 61.641± 0.040 Ma on the La04 orbital solution.
    Description: Published
    Description: 511-533
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Paleocene ; Magnetostratigraphy ; Orbital tuning ; Calcareous nannofossils ; Selandian GSSP ; 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
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  • 66
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    Origin and flux of a gas seep in the Northern Alps (Giswil, Switzerland) (2010)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2017-04-04
    Description: Natural gas seeps in the Alpine region are poorly investigated. However, they can provide useful information regarding the hydrocarbon potential of sedimentary Alpine units and related geofluid migration, typically controlled by pressurized gas accumulations and tectonics. A gas seep located near Giswil, in the Swiss Northern Alps, was investigated, for the first time, for molecular and isotopic gas composition, methane flux to the atmosphere, and gas flux variations over time. The analyses indicated that the gas was thermogenic (CH4 〉 96%; d13C1: )35.5& to )40.2&) and showed evidence of subsurface petroleum biodegradation (13C-enriched CO2, and very low C3+ concentrations). The source rock in the region is marine Type II kerogen, which is likely the same as that providing thermogenic gas in the nearby Wilen shallow well, close to Lake Sarnen. However, the lack of d13CCO2 and d13C3 data for that well prevented us from determining whether the Wilen and Giswil seeps are fed by the same reservoir and seepage system. Gas fluxes from the Giswil seep, measured using a closedchamber system, were significant and mainly from two major vents. However, a substantial gas exhalation from the soil occurs diffusely in an area of at least 115 m2, leading to a total CH4 output conservatively estimated to be at least 16 tonnes per year. Gas flux variations, monitored over a 1-month period by a special tent and flowmeter, showed not only daily meteorological oscillations, but also an intrinsic ‘pulsation’ with periods of enhanced flux that lasted 2–6 h each, occurring every few days. The pulses are likely related to episodes of gas pressure build-up and discharge along the seepage system. However, to date, no relationship to seismicity in the active Sarnen strike-slip fault system has been established.
    Description: Published
    Description: 476-485
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Alps ; isotopes ; methane ; organic geochemistry ; seeps ; Switzerland ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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    Methane emissions from Earth’s degassing: Implications for Mars (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The presence of methane on Mars is of great interest, since one possibility for its origin is that it derives from living microbes. However, CH4 in the martian atmosphere also could be attributable to geologic emissions released through pathways similar to those occurring on Earth. Using recent data on methane degassing of the Earth, we have estimated the relative terrestrial contributions of fossil geologic methane vs. modern methane from living methanogens, and have examined the significance that various geologic sources might have for Mars. Geologic degassing includes microbial methane (produced by ancient methanogens), thermogenic methane (from maturation of sedimentary organic matter), and subordinately geothermal and volcanic methane (mainly produced abiogenically). Our analysis suggests that not, vert, similar80% of the “natural” emission to the terrestrial atmosphere originates from modern microbial activity and not, vert, similar20% originates from geologic degassing, for a total CH4 emission of not, vert, similar28.0×107 tonnes year−1. Estimates of methane emission on Mars range from 12.6×101 to 57.0×104 tonnes year−1 and are 3–6 orders of magnitude lower than that estimated for Earth. Nevertheless, the recently detected martian, Northern-Summer-2003 CH4 plume could be compared with methane expulsion from large mud volcanoes or from the integrated emission of a few hundred gas seeps, such as many of those located in Europe, USA, Mid-East or Asia. Methane could also be released by diffuse microseepage from martian soil, even if macro-seeps or mud volcanoes were lacking or inactive. We calculated that a weak microseepage spread over a few tens of km2, as frequently occurs on Earth, may be sufficient to generate the lower estimate of methane emission in the martian atmosphere. At least 65% of Earth’s degassing is provided by kerogen thermogenesis. A similar process may exist on Mars, where kerogen might include abiogenic organics (delivered by meteorites and comets) and remnants of possible, past martian life. The remainder of terrestrial degassed methane is attributed to fossil microbial gas (not, vert, similar25%) and geothermal-volcanic emissions (not, vert, similar10%). Global abiogenic emissions from serpentinization are negligible on Earth, but, on Mars, individual seeps from serpentinization could be significant. Gas discharge from clathrate-permafrost destabilization should also be considered. Finally, we have shown examples of potential degassing pathways on Mars, including mud volcano-like structures, fault and fracture systems, and major volcanic edifices. All these types of structures could provide avenues for extensive gas expulsion, as on Earth. Future investigations of martian methane should be focused on such potential pathways.
    Description: In press
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Mars ; Methane ; Earth’s degassing ; Seepage ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 68
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    Nannoplankton biostratigraphic calibration of the evaporitic events in the Neogene Fortuna Basin (SE Spain) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Fortuna Basin is an example of a marginal Mediterranean basin with evaporitic sedimentation during the Late Tortonian and Messinian. This basin shows an early restriction event before the main Messinian Salinity Crisis (MSC) that allows the Tortonian Salinity Crisis (TSC) to be proposed as a tectonic uplift event isolating the eastern Betic basins. Four evaporitic events are present in the central part of the Fortuna Basin, from bottom to top: Los Baños Marls Formation (composed by Fenazar Conglomerate Bed, Lower Gypsum Member [Mb] and Sanel Mb), Tale Gypsum Formation (Fm), Chicamo Diatomites and Gypsum Cycles Fm, and Rambla Salada Gypsum Fm. The present work documents the first biostratigraphic dating based on calcareous nannoplankton of these events. The lowest occurrence (LO) of Amaurolithus primus is registered at the upper part of the Sanel Mb, below the Tale Gypsum Fm. The LOs of Amaurolithus delicatus and Reticulofenestra rotaria, which mark the base of the Messinian, occur in the lower part of the Chicamo Cycles Fm, above the Tale Gypsum Fm, the Triquetrorhabdulus rugosus-Nicklithus amplificus integrate form and the LO of Nicklithus cf. amplificus in the upper part of the Chicamo Cycles Fm. Taking into account these results, a new calibration of the available magnetostratigraphic data is presented: the Chicamo Cycles Fm were formed during the reverse chron C3Ar and the Tortonian-Messinian boundary should be found within the Tale Gypsum Fm or near the top of the Sanel Mb. The onset of the TSC, the first restriction phase of the Fortuna Basin, is represented by the Fenazar Conglomerate Bed, bottom of the Los Baños Fm, and not by the Tale Gypsum Fm, as previously considered.
    Description: Published
    Description: 201-217
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Betic Cordillera ; Tortonian Salinity Crisis ; Calcareous nannoplankton ; Messinian ; Fortuna Basin ; 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
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    Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy) (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Pleistocene history of climate control on sedimentation in the Southern Alps-Po Plain system, northern Italy, was reconstructed using an integrated magnetostratigraphic, palynological, and petrographical approach on a 47-m-deep core. The core mainly consists of lacustrine sediments pertaining to the Bagaggera sequence, deposited at the foothills of the Southern Alps during the late Matuyama subchron (0.99-0.78 Ma). At that time, climate worsened globally and locally it caused the progradation of an alluvial fan unit onto the nearby Po Plain, triggering lake formation by damming of a tributary valley. These new data are used in conjunction with data from the literature to highlight and track the effects of climate forcing on sedimentation during the late Matuyama subchron in different orographic and geodynamic settings of the Southern Alps-Po Plain system as part of the greater Alpine area. We found that the episodes of alluvial fan and braidplam progradation observed in the southern foreland of the Alps during the late Matuyama global cooling seem broadly synchronous with the deposition of most of the so-called Gunz and Alterer Deckenschotter deposits in the northern forelands of the Alps as well as with the first major waxing of the Alpine valley glaciers, possibly around the Marine Isotope Stage 22 (~0.87 Ma).
    Description: Regione Lombardia, IREALP
    Description: Published
    Description: 832–846
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Paleomagnetism ; Climate Change ; Early Pleistocene ; Italy ; Stratigraphy ; Petrography ; Palynology ; 03. Hydrosphere::03.01. General::03.01.03. Global climate models ; 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::04.04.08. Sediments: dating, processes, transport ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
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    Human migration into Europe during the late Early Pleistocene climate transition (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: A critical assessment of the available magnetostratigraphic and/or radiometric age constraints on key sites bearing hominin remains and/or lithic industries from southern Europe (Italy, France, Spain) leads us to propose that the main window of early hominin presence in southern Europe is broadly comprised between the Jaramillo subchron and the Brunhes–Matuyama boundary (i.e., subchron C1r.1r, 0.99–0.78 Ma). Within the dating uncertainties, this ~200 ky time window broadly coincides with the late Early Pleistocene global climate transition that contains marine isotope stage (MIS) 22 (~0.87Ma), the first prominent cold stage of the Pleistocene. We suggest that aridification in North Africa and Eastern Europe, particularly harsh during MIS22 times, triggered migration pulses of large herbivores, particularly elephants, from these regions into southern European refugia, and that hominins migrated with them. Finally, we speculate on common pathways of late Early Pleistocene dispersal of elephants and hominins from their home in savannah Africa to southern Europe, elephant and hominin buen retiro. In particular, we stress the importance of the Po Valley of northern Italy that became largely and permanently exposed only since MIS22, thus allowing possibly for the first time in the Pleistocene viable new migration routes for large mammals and hominins across northern Italy to southern France and Spain in the west.
    Description: Published
    Description: 79-93
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Pleistocene ; Magnetostratigraphy ; Hominins ; Migration ; Europe ; Galerian ; Jaramillo ; Brunhes-Matuyama ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 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
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  • 71
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    Changes in the VLP seismic source during the 2007 Stromboli eruption (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Aim of this paper is to identify variations in Very-Long-Period (VLP) source associated with eruptive style changes at Stromboli volcano (Italy) and to retrieve information about the shallow plumbing system that sustains the eruptive activity. We have considered a dataset of 74493 VLP events recorded during the period from January through August 2007, when an effusive eruption occurred (February 27–April 2).We performed a polarization analysis of the entire dataset and divided the considered period into four sub-periods on the basis of polarization characteristics. We then located the events and selected a subset of these events by applying a location quality threshold. The high quality locations demonstrate that during the effusive eruption the VLP sources first moved downward and then moved southwestward. To retrieve information about the geometry of the structures where the source processes take place, we further consider a subset of events and estimate their source mechanisms by using a moment tensor source function (MTSF) inversion technique. Inversion of the waveforms of the VLP events that occurred on February 27 allows us to obtain information about the dynamics of different source centroids distributed along different portions of the shallow magmatic conduits. The structure defined by the locations and source mechanisms shows a greater complexity compared with previous studies and their time variations give an insight into the kinematics of the eruption.
    Description: Published
    Description: 162–171
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: stromboli ; very-long-period events ; seismic source mechanism ; volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 72
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    The Afragola settlement near Vesuvius, Italy: The destruction and abandonment of a Bronze Age village revealed by archaeology, volcanology and rock-magnetism (2009)
    Elsevier
    Details
    Publication Date: 2021-06-15
    Description: Public works in progress in the Campanian plain north of Somma-Vesuvius recently encountered the remains of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di Avellino eruption (3.8 14C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rockmagnetic investigations supplemented the excavations. Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the village, located some 14 km to the north of the inferred vent, and penetrated into the dwellings without causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260– 320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain. The coupling of structural damage and sedimentological analyses indicates that the currents were not destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe injury to humans and animals. The successful escape of the entire population is apparent from the lack of human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. People were thus able to walk barefoot across the already emplaced deposits and escape the subsequent PDCs. The rapid cooling of the deposits was probably due to both their thinness and heat dissipation due to condensation of water vapour released in the mixture by magma–water interaction.
    Description: Published
    Description: 408–421
    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: JCR Journal
    Description: reserved
    Keywords: pyroclastic density current ; Bronze Age ; magnetic fabric ; deposition temperature ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.07. Rock magnetism ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 73
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    Helium isotopes in hydrothermal volcanic fluids of the Azores Archipelago (2009)
    Elsevier
    Details
    Publication Date: 2021-06-25
    Description: We present the first helium isotope data for thermal waters and gas emissions on the islands of Terceira, Graciosa, Faial, Pico and Flores, as well as new data for Sao Miguel. The results allow us to track current mantle degassing associated with the Azores hot spot, to delineate its spatial distribution and to discuss its possible origin. As a general rule, we find that free gases tend to display somewhat higher 3He/4He ratio than groundwaters.We argue that this difference is likely due to radiogenic helium inputs to aquifers duringwater– rock interactions and, therefore, that gas phases are the fluid carriers with the most representative of mantle source signature. The measured 3He/4He ratios (normalized to the air ratio, Ra) range from lower-than-MORB values (5.23–6.07 Ra) on central Sao Miguel, to MORB values on Faial (8.53 Ra) and Flores (8.04 Ra) – located on either side of the Mid-Atlantic Ridge – and to plume-type values on Graciosa (11.2 Ra) and Terceira (13.5 Ra) where free gases also display ten times higher-than-MORB CO2/3He ratios (1.8–2.6×1010). Such a wide He isotopic range and its spatial distribution corroborate with available data for volcanic rocks, indicating that plume's head presently underlies the central part of the archipelago. The plume-type 3He/4He ratios on Terceira and Graciosa agree with geochemical and seismic evidence of a deep-rooted mantle plume feeding the Azores hot spot. Our finding that high 3He/4He ratios correspond to low 3He concentrations and high (arctype) CO2/3He values exclude a simple plume supply of 3He-rich primitive mantle. Instead, the simultaneity of both elevated CO2/3He and 3He/4He ratios is best explained by a 3He-rich contribution from the lower mantle diluted in a CO2-rich feeding plume that contains a recycled altered oceanic plate component. The alternative possibility of an enhanced time-integrated 3He/(U+Th) ratio in the Azores plume due to a greater compatibility of helium relative to U and Th during melting events is difficult to reconcile with the enriched pattern of volcanic rocks from the central islands. In any case, the Azores plume should derive from a mantle reservoir that could escape convective homogenization for a very long period of time, in agreement with subchondritic osmium isotopic ratios in volcanic rocks from the central islands of the archipelago.
    Description: Published
    Description: 70−80
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothemal fluids ; helium isotopes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 74
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    Integrated stratigraphic reconstruction for the last 80 kyr in a deep sector of the Sardinia Channel (Western Mediterranean) (2009)
    Elsevier
    Details
    Publication Date: 2021-07-14
    Description: A quantitative analysis of planktonic foraminifera, coupled with petrophysical and paleomagnetic measurements and 14C AMS calibrations, was carried out on a deep core recovered in the Sardinia Channel (Western Mediterranean Sea), during the CIESM Sub2 survey, providing an integrated stratigraphic time-framework over the last 80 kyr. Significant changes in the quantitative distribution of planktonic foraminifera allowed the identification of several eco-bioevents useful to accurately mark the boundaries of the eco-biozones widely recognised in the Western Mediterranean records and used for large scale correlations. Namely, 10 eco-biozones were identified based on the relative abundance of selected climate sensitive planktonic foraminiferal species. Sixteen codified eco-bioevents were correlated with the Alboran Sea planktonic foraminiferal data and four climatic global events (Sapropel S1, Younger Dryas, Greenland Isotope Interstadial 1, Greenland Isotope Stadial 2, Heinrich event H1-H6) were recognized. The eco-bioevents together with the 14C AMS calibrations allowed us to define an accurate age model, spanning between 2 and 83 kyr. The reliability of the age model was confirmed by comparing the colour reflectance (550 nm%) data of the studied record with the astronomically tuned record from the Ionian sea (ODP-Site 964). A mean sedimentation rate of about 7 cm/kyr included three turbidite event beds that were chronologically constrained within the relative low stand and lowering sea level phases of the MIS 4 and 3. The deep-sea sedimentary record includes a distinct tephra occurring at the base of the core which dates 78 ka cal. BP. The paleomagnetic data provide a well-defined record of the characteristic remanent magnetization that may be used to reconstruct the geomagnetic paleosecular variation for the Mediterranean back to 83 kyr.
    Description: Published
    Description: 725 - 737
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: reserved
    Keywords: Integrated stratigraphy ; Late Neogene marine record ; Eco-bio-events ; Reflectance 550 nm % ; Sardinia Channel ; Western Mediterranean ; 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::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
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  • 75
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    Present-day stress-field modelling of southern Italy constrained by stress and GPS data (2009)
    Elsevier
    Details
    Publication Date: 2020-11-16
    Description: The present-day tectonic setting of the Italian peninsula is very complex and involves competing geodynamic processes. In this context, southern peninsular Italy is characterised by extension along the Apenninic belt and in the Tyrrhenian margin and by transpression in the Apulia-Gargano region. The extension is well defined by means of geological, seismological, and contemporary stress data. For the latter only few data are available in the Apulia-Gargano region, leaving the state of stress in that area unresolved. Here we develop a finite-element model of the southern Italian region in order to predict the contemporary stress field. Our model predictions are constrained by model-independent observations of the orientation of maximum horizontal stress (SHmax), the tectonic regime, and the horizontal velocities derived from GPS observations. We performed a blind test with 31 newly acquired SHmax orientations in the Southern Apennines. These new data come from the analysis of borehole breakouts performed in 46 deep oil exploration wells ranging in depth from 1300 to 5500 m. The model results agree with the stress data that define a prevailing NW-SE SHmax orientation along the Apenninic belt and foredeep and thus are capable to predict the stress field where no stress information is available. We first analyse how much model predictions, based on older data, deviate from present-day stress data and then recalibrate the models based on our new stress data, giving insight into the resolution of both models and data. In the studied region, which is affected by low deformation rates, we find that geodetic data alone cannot resolve such low levels of deformation due to the high relative measurement errors. We conclude that both GPS and stress data are required to constrain model results.
    Description: This research was supported by the Italian Presidenza del Consiglio dei Ministri - Dipartimento della Protezione Civile (DPC) through the INGV-DPC project S1.
    Description: Published
    Description: 193-204
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Description: open
    Keywords: Neotectonics ; Borehole-breakouts ; Southern Apennines ; Finite-element models ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 76
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    Comparison between the 1994–2006 seismic and gravity data from Mt. Etna: New insight into the long-term behavior of a complex volcano (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We investigate the relationship between changes of the gravity field and the release of the seismic energy at Mt. Etna over a 12-year period (1994-2006), during which the volcano exhibited different eruptive patterns. Over the two sub-periods when intense gravity decreases occur, centered on the upper southeastern sector of the volcano (late-1996 to mid-1999 and late-2000 to mid-2001), the strain release curve displays neat long-term accelerations, with many hypocenters clustered in the volume containing the gravity source. Various evidences suggest that, since 1994 and until the breakout of the 2001 eruption, the eastern flank of Etna remained peripheral to the lines of rise of the magma from the deep storage to the surface. Accordingly, we hypothesize that, rather than being directly associated to the migration of the magma, the joint anomalies we found image phases of higher tensile stress on the upper southeastern sector, associated to increase in the rate of microfracturing along the NNW-SSE fracture zone. Such an increase implies a local density (gravity) decrease, and an increase in the release of seismic energy, thus explaining the correlation we observe. The second period of gravity decrease/strain release increase culminated in the breakout of the 2001 flank eruption, as a pressurized deeper magma accumulation used the inferred zone of increasing microfracturing as a path to the surface. This eruption marks an important modification in the structure of Etna’s plumbing system, as also testified by the absence of post-2001 long-term gravity changes and accelerations in the strain release curve and the neat modification of the seismicity and ground deformation patterns. Thus we prove that joint microgravity and seismic studies can allow zones of the medium experiencing an increase in the rate of microfracturing to be identified months to years before a magma batch is conveyed through them to the surface, setting off a lateral eruption.
    Description: Published
    Description: 282–292
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: microgravity changes ; seismic strain release ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
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  • 77
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    Mercury concentration, speciation and budget in volcanic aquifers: Italy and Guadeloupe (Lesser Antilles) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Quantifying the contribution of volcanism to global mercury (Hg) emissions is important to understand the pathways and the mechanisms of Hg cycling through the Earth's geochemical reservoirs and to assess its environmental impacts. While previous studies have suggested that degassing volcanoes might contribute importantly to the atmospheric budget of mercury, little is known about the amount and behaviour of Hg in volcanic aquifers. Here we report on detailed investigations of both the content and the speciation of mercury in aquifers of active volcanoes in Italy and Guadeloupe Island (Lesser Antilles). In the studied groundwaters, total Hg (THg) concentrations range from 10 to 500 ng/l and are lower than the 1000 ng/l threshold value for human health protection fixed by the World Health Organization [WHO (1993): WHO Guidelines for Drinking Water Quality- http://www.who.int/water_sanitation_health/GDWQ/index.htlm]. Positive co-variations of (THg) with sulphate indicate that Hg-SO4-rich acid groundwaters receive a direct input of magmatic/hydrothermal gases carrying mercury as Hg0 (gas). Increasing THg in a volcanic aquifer could thus be a sensitive tracer of magmatic gas input prior to an eruption. Since the complex behaviour and toxicity of mercury in waters depend on its chemical speciation, we carefully determined the different aqueous forms of this element in our samples.We find that dissolved elemental Hg0 (aq) and particulate-bound Hg (HgP) widely prevail in volcanic aquifers, in proportions that highlight the efficiency of Hg adsorption onto colloidal particles. Moreover, we observe that dissolved Hg0 aq and Hg(II) forms coexist in comparable amount in most of the waters, in stark contrast to the results of thermodynamic equilibrium modelling. Therefore, chemical equilibrium between dissolved mercury species in volcanic waters is either prevented by natural kinetic effects or not preserved in collected waters due to sampling/storage artefacts. Finally, we provide a first quantitative comparison of the relative intensity of aqueous transport and atmospheric emissions of mercury at Mount Etna, a very active basaltic volcano.
    Description: Published
    Description: 96-106
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: speciation ; volcanic aquifers ; total and dissolved mercury ; mercury cycling ; volatile budget ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
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  • 78
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    Pleistocene magnetochronology of early hominin sites at Ceprano and Fontana Ranuccio, Italy (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Paleomagnetic analyses were conducted on two cores drilled at Ceprano in central Italy where an incomplete hominin cranium was discovered in1994, as well as on two additional cores from the nearby site of Fontana Ranuccio that yielded hominin remains associated with an Acheulean industry. No evidence for the 0.78 Ma Brunhes–Matuyama boundary was found at Ceprano down to 45 m below the level that yielded the hominin cranium. The Ceprano lithostratigraphy and the paleomagnetic age constraints are broadly consistent with the stratigraphy of the Liri lacustrine sequence of the Latina Valley, constrained by published K–Ar ages between ~0.6 and ~0.35Ma, and according to an age model with magnetic susceptibility supported by pollen facies data, suggest that the level that yielded the hominin cranium has an age of ~0.45 (+0.05, −0.10) Ma. Evidence for the Brunhes–Matuyama boundary was found at Fontana Ranuccio about 40 m below the hominin level, consistent with a K–Ar age of ~0.46 Ma reported for this level. Hence the Ceprano and Fontana Ranuccio hominin occurrences may be of very similar mid-Brunhes age.
    Description: Published
    Description: 255-268
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Pleistocene ; Ceprano ; Fontana Ranuccio ; magnetostratigraphy ; hominins ; Italy ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
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  • 79
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    Spectral properties of volcanic materials from hyperspectral field and satellite data compared with LiDAR data at Mt. Etna (2009)
    ELSEVIER
    Details
    Publication Date: 2017-04-04
    Description: Spectral properties of volcanic materials in the optical region (350–2500 nm) of the electromagnetic spectrum are analyzed. The goal is to characterize air-fall deposits, recent lava flows, and old lava flows based on their spectral reflectance properties and on the textural characteristics (grain size) of pyroclastic deposits at an active basaltic volcano. Data were acquired during a spectroradiometric field survey at Mt. Etna (Italy) in summer 2003 and combined with hyperspectral satellite (Hyperion) and airborne LiDAR (Light Detection and Ranging) data. In addition, air-fall deposits produced by the highly explosive 2002–2003 eruption have been sampled and spectrally characterized at different distances from the new vents. The spectral analysis shows that air-fall deposits are characterized by low reflectance values besides variations in grain size. This distinguishes them from other surface materials. Old lava flows show highest reflectance values due to weathering and vegetation cover. The spectral data set derived from the field survey has been compared to corrected satellite hyperspectral data in order to investigate the Hyperion capabilities to differentiate the surface cover using the reflectance properties. This has allowed us to identify the 2002–2003 air-fall deposits in a thematic image just few months after their emplacement. Moreover, the observed differences in the field spectra of volcanic surfaces have been compared with differences in the signal intensity detected by airborne LiDAR survey showing the possibility to include information on the texture of volcanic surfaces at Mt. Etna. The approach presented here may be particularly useful for remote and inaccessible volcanic areas and also represents a potentially powerful tool for the exploration of extraterrestrial volcanic surfaces.
    Description: Italian National Group of Volcanology
    Description: Published
    Description: 142-155
    Description: 1.10. TTC - Telerilevamento
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna ; Lava ; Reflectance spectra ; Hyperion ; LiDAR ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 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::04.08. Volcanology::04.08.99. General or miscellaneous ; 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::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 80
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    Fault plane orientation of microearthquakes at Mt. etna from the inversion of P-wave rise times (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: crucial point in the analysis of tectonic earthquakes occurring in a volcanic area is the inference of the orientation of the structures along which the ruptures occur. These structures represent zones of weakness which could favor the migration of melt toward the surface and the assessment of their geometry is a fundamental step toward efficient evaluation of volcanic risk. We analyzed a high-quality dataset of 171 low-magnitude, tectonic earthquakes occurred at Mt. Etna during the 2002-2003 eruption. We applied a recently developed technique aimed at inferring the source parameters (source size, dip and strike fault) and the intrinsic quality factor Qp of P waves from the inversion of rise times. The technique is based on numerically calibrated relationships among the rise time of first P waves and the source parameters for a circular crack rupturing at a constant velocity. For the most of the events the directivity source effect did not allow us to constrain the fault plane orientation. For a subset of 45 events with well constrained focal mechanisms we were able to constrain the “true” fault plane orientation. The level of resolution of the fault planes was assessed through a non linear analysis based on the random deviates technique. The significance of the retrieved fault plane solutions and the fit of the assumed source model to data was assessed through a χ-square test. Most of the retrieved fault plane solutions agree with the geometrical trend of known surface faults. The inferred source parameters and Qp are in agreement with the results of previous studies.
    Description: In press
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: open
    Keywords: rise time ; Mt. Etna ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods
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  • 81
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    Hazards from pyroclastic density currents at Mt. Etna (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-03
    Description: Despite the recent recognition of Mount Etna as a periodically violently explosive volcano, the hazards from various types of pyroclastic density currents (PDCs) have until now received virtually no attention at this volcano. Large-scale pyroclastic flows last occurred during the caldera-forming Ellittico eruptions, 15–16 ka ago, and the risk of them occurring in the near future is negligible. However, minor PDCs can affect much of the summit area and portions of the upper flanks of the volcano. During the past ~ 20 years, small pyroclastic flows or base-surge-like vapor and ash clouds have occurred in at least 8 cases during summit eruptions of Etna. Four different mechanisms of PDC generation have been identified during these events: (1) collapse of pyroclastic fountains (as in 2000 and possibly in 1986); (2) phreatomagmatic explosions resulting from mixing of lava with wet rock (2006); (3) phreatomagmatic explosions resulting from mixing of lava with thick snow (2007); (4) disintegration of the unstable flanks of a lava dome-like structure growing over the rim of one of the summit craters (1999). All of these recent PDCs were of a rather minor extent (maximum runout lengths were about 1.5 km in November 2006 and March 2007) and thus they represented no threat for populated areas and human property around the volcano. Yet, events of this type pose a significant threat to the lives of people visiting the summit area of Etna, and areas in a radius of 2 km from the summit craters should be off-limits anytime an event capable of producing similar PDCs occurs. The most likely source of further PDCs in the near future is the Southeast Crater, the youngest, most active and most unstable of the four summit craters of Etna, where 6 of the 8 documented recent PDCs originated. It is likely that similar hazards exist in a number of volcanic settings elsewhere, especially at snow- or glacier-covered volcanoes and on volcano slopes strongly affected by hydrothermal alteration.
    Description: Published
    Description: 148-160
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Pyroclastic density currents ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 82
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    Effects of soil gas permeability and recirculation flux on soil CO2 flux measurements performed using a closed dynamic accumulation chamber (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Dynamic accumulation chamber methods have been extensively used to estimate the total output of CO2 released from active volcanic area. In order to asses the performance and reliability of a closed dynamic system several tests were carried out with different soil permeabilities and soil CO2 fluxes. A special device was used to create a constant one-dimensional CO2 flux through a soil column with a known permeability. Three permeabilities were investigated, ranging between 3.6 × 10− 2 and 3.5 × 10 μm2, as were several CO2 fluxes (ranging between 1.1 × 10− 6 and 6.3 × 10− 5 kg m− 2 s− 1). The results highlight that the accuracy of soil CO2 flux measurements strictly depends on the soil gas permeability and the soil CO2 flux regimen. Generally chamber measurements underestimate CO2 fluxes at low soil permeability and low soil CO2 fluxes, whereas appreciable overestimations occur for high permeability soil, especially for high soil CO2 fluxes. Other tests carried out with different settings for the measurement device, such as the chamber volume and the flux of the pump used to recirculate air through the chamber and the gas analyzer (recirculation flux), revealed a strong dependence of the closed dynamic chamber measurements on the recirculation flux. Low recirculation fluxes (0.2–0.4 l min− 1) decreased the performance of the measurement system, causing underestimations of the actual soil CO2 flux, whereas higher values (0.6–1.0 l min− 1) resulted in overestimations, especially for elevated soil CO2 fluxes. An empirical equation was deduced to allow accumulation chamber fluxes to be calculated very accurately based on soil gas permeabilities measured in the field.
    Description: Published
    Description: 387-393
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Soil CO2 flux measuraments ; Closed dynamic chamber ; soil gas permeability ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 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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  • 83
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    Dike propagation within active central volcanic edifices: constraints from Somma-Vesuvius, Etna and analogue models (2009)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: Dikes within stratovolcanoes are commonly expected to have radial patterns. However, other patterns may also be found, due to regional stresses, magmatic reservoirs and topographic variations. Here, we investigate dike patterns within volcanic edifices by studying dike and fissure complexes at Somma-Vesuvius and Etna (Italy) using analogue models. At the surface, the dikes and fissures show a radial configuration. At depths of tens to several hundreds of metres, in areas exposed by erosion, tangential and oblique dikes are also present. Analogue models indicate that dikes approaching the flanks of cones, regardless of their initial orientation, reorient to become radial (parallel to the maximum gravitational stress). This re-orientation is a significant process in shallow magma migration and may also control the emplacement of dikefed fissures reaching the lower slopes of the volcano.
    Description: This work was partly financed with DPC-INGV LAVA Project.
    Description: Published
    Description: 219-223
    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: Dike propagation ; Central volcanic edifices ; Stress ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 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::04.08.02. Experimental volcanism ; 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 ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 84
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    Integrated stratigraphic reconstruction for the last 80 kyr in a deep sector of the Sardinia Channel (Western Mediterranean) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: A quantitative analysis of planktonic foraminifera, coupled with petrophysical and paleomagnetic measurements and 14C AMS calibrations, was carried out on a deep core recovered in the Sardinia Channel (Western Mediterranean Sea), during the CIESM Sub2 survey, providing an integrated stratigraphic time-framework over the last 80 kyr. Significant changes in the quantitative distribution of planktonic foraminifera allowed the identification of several eco-bioevents useful to accurately mark the boundaries of the eco-biozones widely recognised in the Western Mediterranean records and used for large scale correlations. Namely, 10 eco-biozones were identified based on the relative abundance of selected climate sensitive planktonic foraminiferal species. Sixteen codified eco-bioevents were correlated with the Alboran Sea planktonic foraminiferal data and four climatic global events (Sapropel S1, Younger Dryas, Greenland Isotope Interstadial 1, Greenland Isotope Stadial 2, Heinrich event H1-H6) were recognized. The eco-bioevents together with the 14C AMS calibrations concurred to define an accurate age model, spanning between 2 and 83 kyr cal. BP. The reliability of the age model was confirmed by comparing the colour reflectance (550 nm%) data of the studied record with the astronomically tuned one of the Ionian sea (ODP-Site 964). A mean sedimentation rate of about 7 cm/kyr was evaluated including three turbidite event beds that were chronologically constrained within the relative low stand and lowering sea level phases of the MIS 4 and MIS 3. The deep sea sedimentary record includes a distinct tephra occurring at the base of the core which dates 79 ka. The paleomagnetic data provide a well-defined record of the characteristic remanent magnetization that may be used to reconstruct the geomagnetic paleosecular variation for the Mediterranean back to 83 kyr cal. BP.
    Description: In press
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: open
    Keywords: integrated stratigraphy, late Neogene marine record, eco-bio-events, reflectance 550 nm %, Sardinia ; 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::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
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  • 85
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    Methane fluxes from the soils in active volcanic areas: the case of Pantelleria Island (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Methane, the most abundant hydrocarbon in the atmosphere, plays an important role in the Earth’s atmospheric chemistry and radiative balance being the second most important greenhouse gas after CO2. Methane is released to the atmosphere by a wide number of sources, both natural and anthropogenic, with the latter being twice as large as the former (Kvenvolden and Rogers, 2005). It has recently been established that significant amounts of geological methane, produced within the Earth’s crust, are currently released naturally into the atmosphere (Etiope, 2004). Among natural sources the volcanic/geothermal emissions are probably the least constrained. Recent estimations for volcanic and geothermal systems in Europe (Etiope et al. 2007) gave a rather large provisional range (4-16 kt/a) that claims for much more field measurements in order to widen the current database and decrease the present uncertainties. Pantelleria is an active volcanic complex, at present in quiescent status, hosting a high enthalpy geothermal system. Explorative geothermal wells tapped an exploitable water-dominated reservoir at 600-800 m depth with maximum measured temperatures of 250 °C. While some data are available on diffuse CO2 fluxes, data on CH4 are available only for fumarolic fluids. In the present study we measured CH4 fluxes in the area of Favara Grande characterized by intense diffuse degassing and widespread signs of geothermal activity (fumaroles, steaming grounds and large zones devoid of vegetation). Values range from negative (-43 to 0 mgCH4 m2 day), typical of soils with methanotrophic activity, up to 3500 mgCH4 m2 day in the most thermalized area. The preliminary estimate of the methane release from the area of Favara Grande is about 2.5 t/a. Extrapolation to the whole volcanic/geothermal system of Pantelleria gives about 10 t/a.
    Description: Published
    Description: Davos, Switzerland
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: open
    Keywords: soil gases ; methane output ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 86
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    The evolution of a dynamic geological system: the support of a GIS for geochemicd measurements at the fumarole field of Vulcano, Italy (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The island of Vulcano (Aeolian arc, Southern Italy) has displayed several periods of volcanic unrest since the end of the last eruption (1890). We report here results obtained from a long-term survey concerning variations of both the steam output and the exhaling surface area at the sun~mit crater fumarolic field of La Fossa. The field measurements analysed in a Geographiciil Information System (GIS: show a highly dynamic volcanic system in which deep variations in the geochemishy and the temperature of the released fluids were accompanied by fluctuations in the mass output of steam and the topography of the crater field. The use of a GIS facilitated digitized reconstructions of maps of the crater field in addition to analysis (of the steam flux data. The furnarolic field expanded its surface area from 50 m2 in 1983 to more than 2400 m* in 1995, accompanied by an increase in steam output from 152 to about 1400 tonnes per day. The possibility that the observed phenomena are related to volcano-tectonic activity and to magma uprising is taken into consideration.
    Description: Published
    Description: 253-263
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: volcanic surveillance ; Steam output ; tectonic lines ; flux ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 87
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    Geochemical evaluation of observed changes in volcanic activity during the 2007 eruption at Stromboli (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: On February 27, 2007 a new eruption started at Stromboli that lasted until April 2 and included a paroxysmal explosion on March 15. Geochemical monitoring carried out over several years revealed some appreciable variations that preceded both the eruption onset and the explosion. The carbon dioxide (CO2) flux from the soil at Pizzo Sopra La Fossa markedly increased a few days before the eruption onset, and continued during lava effusion to reach its maximum value (at 90,000 g m−2 d−1) a few days before the paroxysm. Almost contemporarily, the δ13CCO2 of the SC5 fumarole located in the summit area increased markedly, peaking just before the explosion (δ13CCO2~−1.8‰). Following the paroxysm, helium (He) isotopes measured in the gases dissolved in the basal thermal aquifer sharply increased. Almost contemporarily, the automatic station of CO2 flux recorded an anomalous degassing rate. Also temperatures and the vertical thermal gradient, which had been measured since November 2006 in the soil at Pizzo Sopra La Fossa, showed appreciable variabilities that lasted until the end of the eruption. The geochemical variations indicated the degassing of a new batch of volatile-rich magma that preceded and probably fed the paroxysm. The anomalous 3He/4He ratio suggested that the ascent of a second batch of volatile-rich magma toward the surface was probably responsible of the resumption of the ordinary activity. A comparison with the geochemical variations observed during the 2002–2003 eruption indicated that the 2007 eruption was less energetic.
    Description: Published
    Description: 246-254
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: geochemistry ; eruption ; dissolved gases ; Stromboli ; volcanic activity ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 88
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    Dike propagation in volcanic edifices: Overview and possible developments (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Eruptions are fed by dikes; therefore, better knowledge of dike propagation is necessary to improve our understanding of how magma is transferred and extruded at volcanoes. This study presents an overview of dike patterns and the factors controlling dike propagation within volcanic edifices. Largely based on published data, three main types of dikes (regional, circumferential and radial) are illustrated and discussed. Dike pattern data from 25 volcanic edifices in different settings are compared to derive semi-quantitative relationships between the topography (relief, shape, height, and presence of sector collapses) of the volcano, tectonic setting (presence of a regional stress field), and mean composition (SiO2 content). The overview demonstrates how dike propagation in a volcano is not a random process; rather, it depends from the following factors (listed in order of importance): the presence of relief, the shape of the edifice and regional tectonic control. We find that taller volcanoes develop longer radial dikes, whose (mainly lateral) propagation is independent of the composition of magma or the aspect ratio of the edifice. Future research, starting from these preliminary evaluations, should be devoted to identifying dike propagation paths and likely locations of vent formation at specific volcanoes, to better aid hazards assessment.
    Description: Partly fundedwith DPC-INGVfunds (LAVAProject).
    Description: Published
    Description: 67–77
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: dikes ; volcanoes ; topography ; tectonic setting ; eruptions ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 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::04.07.05. 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::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 89
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    Intrusion of eccentric dikes: The case of the 2001 eruption and its role in the dynamics of Mt. Etna volcano (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The 2001 eruption represents one of the most studied events both from volcanological and geophysical point of view on Mt. Etna. This eruption was a crucial event in the recent dynamics of the volcano, marking the passage from a period (March 1993–June 2001) of moderate stability with slow, continuous flank sliding and contemporaneous summit eruptions, to a period (July 2001 to present) of dramatically increased flank deformations and flank eruptions. We show new GPS data and high precision relocation of seismicity in order to demonstrate the role of the 2001 intrusive phase in this change of the dynamic regime of the volcano. GPS data consist of two kinematic surveys carried out on 12 July, a few hours before the beginning of the seismic swarm, and on 17 July, just after the onset of eruptive activity. A picture of the spatial distribution of the sin-eruptive seismicity has been obtained using the HypoDD relocation algorithm based on the double-difference (DD) technique. Modeling of GPS measurements reveals a southward motion of the upper southern part of the volcano, driven by a NNW–SSE structure showing mainly left-lateral kinematics. Precise hypocenter location evidences an aseismic zone at about sea level, where the magma upraise was characterized by a much higher velocity and an abrupt westward shift, revealing the existence of a weakened or ductile zone. These results reveal how an intrusion of a dike can severely modify the shallow stress field, triggering significant flank failure. In 2001, the intrusion was driven by a weakened surface, which might correspond to a decollement plane of the portion of the volcano affected by flank instability, inducing an additional stress testified by GPS measurements and seismic data, which led to an acceleration of the sliding flanks.
    Description: This work was funded by the Istituto Nazionale di Geofisica e Vulcanologia and by the Dipartimento per la Protezione Civile (Italy).
    Description: Published
    Description: 78–86
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    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: stress release ; dike ; volcano-tectonics ; flank instability ; Mt. Etna ; instrumental monitoring ; 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::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 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::04.06. Seismology::04.06.99. General or miscellaneous ; 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::04.07.05. 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::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.02. Seismological data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 90
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    Late Matuyama climate forcing on sedimentation at the margin of the southern Alps (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Pleistocene history of climate control on sedimentation in the Southern Alps-Po Plain system, northern Italy, was reconstructed using an integrated magnetostratigraphic, palynological, and petrographical approach on a 47-m-deep core. The core mainly consists of lacustrine sediments pertaining to the Bagaggera sequence, deposited at the foothills of the Southern Alps during the late Matuyama subchron (0.99–0.78 Ma). At that time, climate worsened globally and locally it caused the progradation of an alluvial fan unit onto the nearby Po Plain, triggering lake formation by damming of a tributary valley. These new data are used in conjunction with data from the literature to highlight and track the effects of climate forcing on sedimentation during the late Matuyama subchron in different orographic and geodynamic settings of the Southern Alps-Po Plain system as part of the greater Alpine area. We found that the episodes of alluvial fan and braidplain progradation observed in the southern foreland of the Alps during the late Matuyama global cooling seem broadly synchronous with the deposition of most of the so-called Günz and Älterer Deckenschotter deposits in the northern forelands of the Alps as well as with the first major waxing of the Alpine valley glaciers, possibly around the Marine Isotope Stage 22 (~0.87 Ma).
    Description: In press
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Pleistocene ; magnetostratigraphy ; pollen analysis ; sand petrography ; Alps ; Po Plain ; lacustrine sequence ; alluvial fan ; 02. Cryosphere::02.03. Ice cores::02.03.05. Paleoclimate ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology ; 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
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  • 91
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    Filling the North European Early/Middle Eocene (Ypresian/Lutetian) boundary gap: Insights from the Pyrenean continental to deep-marine record (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Early/Middle Eocene (Ypresian/Lutetian) transition is represented by a hiatus in many North European sections, including those in which the classic stratotypes were originally defined. However, the Global Stratotype Section and Point of the Lutetian Stage, which is still pending definition, should be placed at a globally correlatable event included within that unrepresented interval. The Pyrenean Eocene outcrops display sedimentary successions that offer the rare opportunity to analyse the Ypresian/Lutetian boundary interval in almost continuous sections and in very different settings. Seven reference stratigraphic sections were selected on the basis of their quality and correlated by means of biomagnetostratigraphic data. This correlation framework casts light on the sequence of chronostratigraphic events that characterize the Ypresian/Lutetian boundary interval, which may prove useful in defining the main correlation criterion of the base of the Lutetian. All of the Pyrenean sections show a similar sedimentary evolution, despite being up to 350 km apart from each other, containing deposits of different origins (intrabasinal carbonate sediments, siliciclastic sediments sourced from the Iberian plate, and terrigenous sediments sourced from the uplifting Pyrenees) and despite having been accumulated in different sedimentary environments (from continental to deep marine) and in different geodynamic settings (piggy-back basin, foreland basin and cratonic margin). This common evolution can be readily interpreted in terms of a sea-level driven depositional sequence whose lowstand and transgressive systems tracts are included within the Ypresian/Lutetian boundary interval. The Pyrenean Ypresian/Lutetian depositional sequence can reasonably be correlated with depositional sequences from classic North European areas, shedding light on the palaeoenvironmental history which in those areas has not been recorded. Furthermore, these depositional sequences may possibly correlate with others from the Antarctic Ocean and from New Jersey, as well as with oceanic temperature variations, suggesting that they might be the result of climatically-driven glacioeustatic sea-level changes. Should this hypothesis prove correct, it would confirm previous suggestions that the onset of Antarctic glaciations needs to be backshifted to the late Ypresian at least.
    Description: Published
    Description: 313-332
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: reserved
    Keywords: Eocene ; Lutetian ; Chronostratigraphy ; Sequence stratigraphy ; Climate ; Pyrenees ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.05. Geomagnetism::04.05.02. Geomagnetic field variations and reversals ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
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  • 92
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    Nitrogen Isotopes in Volcanic Fluids of Different Geodynamic Settings (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Nitrogen isotopes , N2/36Ar and 3He/4He were measured in volcanic fluids within different geodynamic settings. Subduction zones are represented by Aeolian archipelago, Mexican volcanic belt and Hellenic arc, spreading zones – by Socorro island in Mexico and Iceland and hot spots by Iceland and Islands of Cabo Verde. The δ15N values, corrected for air contamination of volcanic fluids, discharged from Vulcano Island (Italy), highlighted the presence of heavy nitrogen (around +4.3 ±0.5‰). Similar 15N values (around +5‰), have been measured for the fluids collected in the Jalisco Block, that is a geologically and tectonically complex forearc zone of the northwestern Mexico [1]. Positive values (15N around +3‰) have been also measured in the volcanic fluids discharged from Nysiros island located in the Ellenic Arc characterized by subduction processes. All uncorrected data for the Socorro island are in the range of -1 to -2‰. The results of raw nitrogen isotope data of Iceland samples reveal more negative isotope composition (about -4.4‰). On the basis of the non-atmospheric N2 fraction (around 50%) the corrected data of 15N for Iceland are around -16‰, very close to the values proposed by [2]. In a volcanic gas sample from Fogo volcano (Cabo Verde islands) we found a very negative value: -9.9‰ and -15‰ for raw and corrected values, respectively.
    Description: Geochimica et Cosmochimica Acta
    Description: Published
    Description: Davos, Switzerland
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: open
    Keywords: Nitrogen Isotopes ; Helium Isotopes ; Volcanic fluids ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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  • 93
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    Hydrothermal methane fluxes from the soil at Pantelleria island (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Chemical and isotopic analyses of the main gas manifestations of the island of Pantelleria (Italy) were used to gain insight on the origin of the released methane. Results indicate that the most probable origin is through abiogenic reactions within the hydrothermal system. Methane and CO2 flux measurements from the soils were made with the accumulation chamber method in an area of about 0.015 km2 within the main fumarolic area of the island (Favara Grande). The 23 measurements range from –34 to 3550 mg m-2 d-1 for CH4 and from 0.6 to 379 g m-2 d-1 for CO2. The relationships between CH4 and CO2 fluxes and the CH4/CO2 ratios in the gases collected between 25 and 100 cm depth provide evidence for methanotrophic processes within the soils. Methane output for the surveyed area was calculated in 2.5 t a-1 and extrapolated to about 5-10 t a-1 for the entire volcanic/hydrothermal system of the island. Previous higher estimates of the CH4 output at Pantelleria (Etiope et al., 2007 - J. Volcanol. Geotherm. Res., 165, 76 – 86) were based on soil CO2 output and CH4/CO2 ratios in fumarolic gases; the present work provides the first direct CH4 flux data and it suggests that methanotrophic activity in the soil could be substantial in reducing the CH4 emission to the atmosphere.
    Description: Published
    Description: 147-157
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothermal systems ; gas geochemistry ; isotope composition ; methane output ; methanotrophic consumption ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 94
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    Mechanisms for ground-surface fracturing and incipient slope failure associated with the 2001 eruption of Mt. Etna, Italy: analysis of ephemeral field data (2008)
    Elsevier
    Details
    Publication Date: 2020-11-26
    Description: During the July^August 2001 eruption of Mt. Etna development of extensional fractures/faults and grabens accompanied magma intrusion and subsequent volcanic activity. During the first days of the eruption, we performed an analysis of attitude, displacement and propagation of fractures and faults exposed on the ground surface in two sites, Torre del Filosofo and Valle del Leone, located along the same fracture system in the region surrounding the Valle del Bove depression on the eastern flank of Mt. Etna. Fractures and faults formed as the consequence of a shallow intruding dyke system that fed the several volcanic centres developed along the fracture system. The investigated sites differ in slope attitude and in geometrical relationships between fractures and slopes. In particular, the fracture system propagated parallel to the gentle slope (67‡ dip) in the Torre del Filosofo area, and perpendicular to the steep slope (V25‡ dip) in the Valle del Leone area. In the Torre del Filosofo area, slight graben subsidence and horizontal extension of the ground surface by about 3 m were recorded. In the Valle del Leone area, extensional faulting forming a larger and deeper graben with horizontal extension of the ground surface by about 10 m was recorded. For the Valle del Leone area, we assessed a downhill dip of 14‡ for the graben master fault at the structural level beneath the graben where the fault dip shallows. These results suggest that dyke intrusion at Mount Etna, and particularly in the region surrounding the Valle del Bove depression, may be at the origin of slope failure and subsequent slumps where boundary conditions, i.e. geometry of dyke, slope dip and initial shear stress, amongst others, favour incipient failures.
    Description: Published
    Description: 281-294
    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: dykes ; extensional fractures ; grabens ; slope failures ; 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::04.07.02. 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::04.08.05. 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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  • 95
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    The late Pleistocene pyroclastic deposits of the Campanian Plain: New insights into the explosive activity of Neapolitan volcanoes (2008)
    Elsevier
    Details
    Publication Date: 2020-12-21
    Description: The lithological and compositional characteristics of eighteen different pyroclastic deposits of Campanian origin, dated between 125 cal ky BP and 22 cal ky BP, were described. The pyroclastic deposits were correlated among different outcrops mainly located on the Apennine slopes that border the southern Campanian Plain. They were grouped in two main stratigraphic and chronologic intervals of regional significance: a) between Pomici di Base (22.03 cal ky BP; Somma–Vesuvius) and Campanian Ignimbrite (39 cal ky BP; Campi Flegrei) eruptions; and b) older than Campanian Ignimbrite eruption. Three new 14C AMS datings support the proposed correlations. Six eruptions were attributed to the Pomici di Base- Campanian Ignimbrite stratigraphic interval, while twelve eruptions are older than Campanian Ignimbrite. Of the studied deposits two originated from Ischia island, five are related to Campi Flegrei, and three to Somma– Vesuvius. Two eruptions have an uncertain correlation with Somma–Vesuvius or Campi Flegrei, while six eruptions remain of uncertain source. Minimum volumes of five eruptions were assessed, ranging between 0.5 km3 and 4 km3. Two of the studied deposits were correlated with Y-3 and X-5 tephra layers, which are widely dispersed in the central Mediterranean area. The new stratigraphic and chronologic data provide an upgraded chrono-stratigraphy for the explosive activity of Neapolitan volcanoes in the period between 125 and 22 cal ky BP.
    Description: Published
    Description: 19–48
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Neapolitan volcanoes ; late Pleistocene ; explosive eruptions ; Somma–Vesuvius ; 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::04.04.10. Stratigraphy ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
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  • 96
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    Carbon dioxide degassing from Tuscany and Northern Latium (Italy) (2008)
    Elsevier
    Details
    Publication Date: 2021-01-07
    Description: The CO2 degassing process from a large area on the Tyrrhenian side of central Italy, probably related to the input into the upper crust of mantle fluids, was investigated in detail through the geochemical study of gas emissions and groundwater. Mass-balance calculations and carbon isotopes show that over 50% of the inorganic carbon in regional groundwater is derived from a deep source highlighting gas−liquid separation processes at depth. The deep carbonate−evaporite regional aquifer acts as the main CO2 reservoir and when total pressure of the reservoir fluid exceeds hydrostatic pressure, a free gas phase separates from the parent liquid and escapes toward the surface generating gas emissions which characterise the study area. The distribution of the CO2 flux anomalies and the location of high PCO2 springs and gas emissions suggest that the storage and the expulsion of the CO2 toward the atmosphere are controlled by the geological and structural setting of the shallow crust. The average CO2 flux and the total amount of CO2 discharged by the study area were computed using surface heat flow, enthalpy and CO2 molality of the liquid phase circulating in the deep carbonate−evaporite aquifer. The results show that the CO2 flux varies from 1×104 mol y−1 km−2 to 5×107 mol y−1 km−2, with an average value of 4.8×106 mol y−1 km−2, about five times higher than the value of 1×106 mol y−1 derived by Kerrick et al. [Kerrick, D.M., McKibben, M.A., Seward, T.M., Caldeira, K., 1995. Convective hydrothermal CO2 emission from high heat flow regions. Chem. Geol. 121, 285–293] as baseline for terrestrial CO2 emissions. The total CO2 discharged from the study area is 0.9×1011 mol y−1, confirming that Earth degassing from Tyrrhenian central Italy is a globally relevant carbon source
    Description: Published
    Description: 89–102
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: Earth degassing ; carbon dioxide ; CO2 flux ; groundwater ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 97
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    Monitoring ash emission episodes at Mt. Etna: the 16 November 2006 case study (2008)
    Elsevier
    Details
    Publication Date: 2020-11-17
    Description: Mt. Etna in Sicily (Italy) is one of the best monitored basaltic volcanoes in the world due to the frequent eruptions from its summit and flanks. Routine monitoring carried out by the Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, for surveillance purposes permits following the evolution of volcanic events. In this paper, a description of the ash monitoring system as occurred during the August-December 2006 summit eruption at the Southeast Crater (SEC) is shown. This eruption was characterized by lava flow effusions and vigorous Strombolian activity. Eighteen paroxysmal episodes occurred up to the end of November, forming weak ash plumes accompanied by moderate tephra fallout over Etna’s slopes. During these events, we applied a multidisciplinary approach to promptly monitor the paroxysmal activity and the associated tephra fallout, through analysis from seismic tremor and observation from live-cameras, sampling operations, mapping and analysis of the deposit. During the most significant episodes, we carried out textural and grain-size analysis on tephra samples and evaluated the whole grain-size deposit and the erupted volume, while numerical simulations of tephra dispersal allowed better understanding eruptive dynamics. An example of this methodology is applied to the 16 November episode, during which seismic tremor furnished important constraints on the chronology. This paroxysmal eruption produced light fallout on the north-east sector of the volcano for about ten hours and a number of debris-avalanches over the slopes of the SEC cone. The erupted deposit was composed for the most part of lithic components and characterized by a whole grain-size distribution centered on 2.2 , while its total mass was evaluated 7 x 106 kg. On the whole, such integrated studies help to obtain information on magma fragmentation and eruptive mechanisms, to characterize the explosive styles shown by Etna and finally, to better approach the monitoring of imminent eruptions.
    Description: FIRB Italian project “Sviluppo Nuove Tecnologie per la Protezione e Difesa del Territorio dai Rischi Naturali” funded by Italian Minister of University and Research
    Description: Published
    Description: 123-134
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Description: open
    Keywords: Mt. Etna ; volcanic ash monitoring ; tephra deposit ; 2006 eruption ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 98
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    The July-August 2001 eruption of Mt. Etna (Sicily) (2008)
    Springer-Verlag
    Details
    Publication Date: 2017-04-04
    Description: The July-August 2001 eruption of Mt. Etna stimulated widespread public and media interest, caused significant damage to tourist facilities, and for several days threatened the town of Nicolosi on the S flank of the volcano. Seven eruptive fissures were active, five on the S flank between 3050 and 2100 m altitude, and two on the NE flank between 3080 and 2600 m elevation. All produced lava flows over various periods during the eruption, the most voluminous of which reached a length of 6.9 km. Mineralogically the 2001 lavas fall into two distinct groups, indicating that magma was supplied through two different and largely independent pathways, one extending laterally from the central conduit system through radial fissures, the other being a vertically ascending eccentric dike. Furthermore one of the eccentric vents, at 2570 m elevation, was the site of vigorous phreatomagmatic activity as the dike cut through a shallow aquifer, both during the intial and closing stages of the eruption. For six days the magma column feeding this vent was more or less effectively sealed from the aquifer, permitting powerful explosive and effusive magmatic activity. While the eruption was characterized by a highly dynamic evolution, complex interactions between some of the eruptive fissures, and changing eruptive styles, its total volume (~25 x 106 m3 of lava and 5-10 x 106 m3 of pyroclastics) was relatively small in comparison with other recent eruptions of Etna. Effusion rates were calculated on a daily basis and reached peaks of 14-16 m3 s-1 while the average effusion rate at all fissures was about 11 m3 s-1, which is not exceptionally high. The eruption showed a number of peculiar features, but none of these (except the contemporaneous lateral and eccentric activity) represented a significant deviation from Etna's eruptive behavior in the long term. However, the 2001 eruption could be but the first in a series of flank eruptions, some of which might be more voluminous and hazardous. Placed in a long-term context, the eruption confirms a distinct trend, initiated during the past 50 years, toward higher production rates and more frequent eruptions, which might bring Etna back to similar levels of activity as during the early to mid 17th century.
    Description: Published
    Description: 461-476
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna ; 2001 eruption ; Lava flow-field evolution ; Central-lateral vs. eccentric activity ; Phreatomagmatism ; Eruption dynamics ; 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::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.03. 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
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  • 99
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    Hydrochemical dynamics of the “lake–spring” system in the crater of El Chichón volcano (Chiapas, Mexico) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: El Chichón volcano (Chiapas, Mexico) erupted violently in March–April 1982, breaching through the former volcano–hydrothermal system. Since then, the 1982 crater has hosted a shallow (1–3.3 m, acidic (pH ∼ 2.2) and warm (∼ 30 °C) crater lake with a strongly varying chemistry (Cl/SO4=0–79 molar ratio). The changes in crater lake chemistry and volume are not systematically related to the seasonal variation of rainfall, but rather to the activity of near-neutral geyser-like springs in the crater (Soap Pool). These Soap Pool springs are the only sources of Cl for the lake. Their geyser-like behaviour with a long-term (months to years) periodicity is due to a specific geometry of the shallow boiling aquifer beneath the lake, which is the remnant of the 1983 Cl-rich (24,000 mg/l) crater lake water. The Soap Pool springs decreased in Cl content over time. The zero-time extrapolation (1982, year of the eruption) approaches the Cl content in the initial crater lake,meanwhile the extrapolation towards the future indicates a zero-Cl content by 2009±1. This particular situation offers the opportunity to calculate mass balance and Cl budget to quantify the lake–spring system in the El Chichón crater. These calculations show that the water balance without the input of SP springs is negative, implying that the lake should disappear during the dry season. The isotopic composition of lake waters (δD and δ18O) coincide with this crater lake-SP dynamics, reflecting evaporation processes and mixing with SP geyser and meteoric water. Future dome growth, not observed yet in the post-1982 El Chichón crater, may be anticipated by changes in lake chemistry and dynamics.
    Description: Published
    Description: 237–248
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: El Chichón volcano ; crater lake–Spring dynamics ; fluid geochemistry ; stable isotopes ; monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
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  • 100
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    Estimating thermal inflow to El Chichón crater lake using the energy-budget, chemical and isotope balance approaches (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: El Chichón crater lake appeared immediately after the 1982 catastrophic eruption in a newly formed, 1-km wide, explosive crater. During the first 2 years after the eruption the lake transformed from hot and ultraacidic caused by dissolution of magmatic gases, to a warm and less acidic lake due to a rapid “magmatic-tohydrothermal transition” — input of hydrothermal fluids and oxidation of H2S to sulfate. Chemical composition of the lake water and other thermal fluids discharging in the crater, stable isotope composition (δD and δ18O) of lake water, gas condensates and thermal waters collected in 1995–2006 were used for the mass-balance calculations (Cl, SO4 and isotopic composition) of the thermal flux from the crater floor. The calculated fluxes of thermal fluid by different mass-balance approaches become of the same order of magnitude as those derived from the energy-budget model if values of 1.9 and 2 mmol/mol are taken for the catchment coefficient and the average H2S concentration in the hydrothermal vapors, respectively. The total heat power from the crater is estimated to be between 35 and 60 MW and the CO2 flux is not higher than 150 t/day or ~200 gm−2 day−1.
    Description: Published
    Description: 472-481
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: El Chichón ; crater lake ; mass-energy budget ; CO2 flux ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data
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