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  • 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics  (41)
  • 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems  (32)
  • Apennines
  • Elsevier  (66)
  • Elsevier Science Limited  (17)
  • Blackwell Publishing Ltd  (2)
  • 2010-2014  (37)
  • 2005-2009  (48)
  • 1990-1994
  • 1980-1984
  • 1925-1929
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Year
  • 1
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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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Helium–strontium isotope constraints on mantle evolution beneath the Roman Comagmatic Province, Italy (2005)
    Elsevier
    Details
    Publication Date: 2020-12-03
    Description: A study of the He isotopic ratios of fluid inclusions in olivine and pyroxene from the Roman Comagmatic Province (RCP),Italy, is presented together with 87Sr/86Sr isotope compositions of the whole rock or pyroxene phenocrysts. A clear covariation in He and Sr isotopes is apparent, with a strong northward increase in radiogenic He and Sr being evident. He and Sr isotopes ratios range from 3He/4He = 5.2 Ra and 87Sr/86Sr = 0.7056 in south Campania, to 3He/4He = 0.44 Ra and 87Sr/86Sr = 0.715905 in the northernmost Latium. Helium isotope ratios are significantly lower than MORB values and are among the lowest yet measured in subduction zone volcanism. The 3He/4He of olivine and pyroxene phenocryst-hosted volatiles appear to be little influenced by posteruptive processes and magma–crust interaction. The 3He/4He–87Sr/86Sr covariation is consistent with binary mixing between an asthenospheric mantle similar to HIMU ocean island basalts, and an enriched (radiogenic) mantle end member generated from subduction of the Ionian/Adriatic plate. The contribution of radiogenic He from metasomatic fluids and postmetasomatism radiogenic ingrowth in the wedge is strongly dependent on the initial He concentration of the mantle. Only when asthenosphere He concentrations are substantially lower than the MORB source mantle, and metasomatism occurred at the beginning of the subduction (f30 Ma), can ingrowth in the mantle wedge account for the 3He/4He of the most radiogenic basalts.
    Description: - European Social Fund - Scottish Universities - Carnegie Trust for the Universities of Scotland.
    Description: Published
    Description: 295–308
    Description: partially_open
    Keywords: Roman Comagmatic Province ; fluid inclusions ; helium ; strontium ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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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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  • 4
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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
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  • 5
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    Tracing thermal aquifers of El Chichón volcano-hydrothermal system (México) with 87Sr/86Sr, Ca/Sr and REE (2011)
    Elsevier
    Details
    Publication Date: 2020-11-26
    Description: The volcano–hydrothermal system of El Chichón volcano, Chiapas, Mexico, is characterized by numerous thermal manifestations including an acid lake, steam vents and boiling springs in the crater and acid and neutral hot springs and steaming ground on the flanks. Previous research on major element chemistry reveals that thermal waters of El Chichón can be divided in two groups: (1) neutral waters discharging in the crater and southern slopes of the volcano with chloride content ranging from 1500 to 2200 mg/l and (2) acid-toneutral waters with Cl up to 12,000 mg/l discharging at the western slopes. Our work supports the concept that each group of waters is derived from a separate aquifer (Aq. 1 and Aq. 2). In this study we apply Sr isotopes, Ca/Sr ratios and REE abundances along with the major and trace element water chemistry in order to discriminate and characterize these two aquifers. Waters derived from Aq. 1 are characterized by 87Sr/86Sr ratios ranging from 0.70407 to 0.70419, while Sr concentrations range from 0.1 to 4 mg/l and Ca/Sr weight ratios from 90 to 180, close to average values for the erupted rocks. Waters derived from Aq. 2 have 87Sr/86Sr between 0.70531 and 0.70542, high Sr concentrations up to 80 mg/l, and Ca/Sr ratio of 17–28. Aquifer 1 is most probably shallow, composed of volcanic rocks and situated beneath the crater, within the volcano edifice. Aquifer 2 may be situated at greater depth in sedimentary rocks and by some way connected to the regional oil-gas field brines. The relative water output (l/s) from both aquifers can be estimated as Aq. 1/Aq. 2– 30. Both aquifers are not distinguishable by their REE patterns. The total concentration of REE, however, strongly depends on the acidity. All neutral waters including high-salinity waters from Aq. 2 have very low total REE concentrations (b0.6 μg/l) and are characterized by a depletion in LREE relative to El Chichón volcanic rock, while acid waters from the crater lake (Aq. 1) and acid AS springs (Aq. 2) have parallel profile with total REE concentration from 9 to 98 μg/l. The highest REE concentration (207 μg/l) is observed in slightly acid shallow cold Ca-SO4 ground waters draining fresh and old pyroclastic deposits rich in magmatic anhydrite. It is suggested that the main mechanism controlling the concentration of REE in waters of El Chichón is the acidity. As low pH results from the shallow oxidation of H2S contained in hydrothermal vapors, REE distribution in thermal waters reflects the dissolution of volcanic rocks close to the surface or lake sediments as is the case for the crater lake.
    Description: -
    Description: Published
    Description: 55-66
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrogeochemistry ; geothermal systems ; Sr isotopes ; REE ; El Chichón Volcano ; 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::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 6
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    Multidisciplinary study of the Tindari Fault (Sicily, Italy) separating ongoing contractional and extensional compartments along the active Africa–Eurasia convergent boundary (2013)
    Elsevier Science Limited
    Details
    Publication Date: 2020-12-15
    Description: The Africa–Eurasia convergence in Sicily and southern Calabria is currently expressed by two different tectonic and geodynamic domains: thewestern region, governed by a roughlyN–S compression generated by a continental collision; the eastern one, controlled by a NW–SE extension related to the south-east-directed expansion of the Calabro–Peloritan Arc. The different deformation pattern of these two domains is accommodated by a right-lateral shear zone (Aeolian–Tindari–Letojanni fault system) which, from the Ionian Sea, north of Mt. Etna, extends across the Peloritani chain to the Aeolian Islands. In this work, we study the evidence of active tectonics characterizing this shear zone, through the analysis of seismic and geodetic data acquired by the INGV networks in the last 15 years. The study is completed by structural and morphological surveys carried out between Capo Tindari and the watershed of the chain. The results allowed defining a clear structural picture depicting the tectonic interferences between the two different geodynamic domains. The results indicate that, besides the regional ~N130°E horizontal extensional stress field, another one, NE–SW-oriented, is active in the investigated area. Both tension axes are mutually independent and have been active up to the present at different times. The coexistence of these different active horizontal extensions is the result of complex interactions between several induced stresses: 1) the regional extension (NW–SE) related to the slab rollback and back-arc extension; 2) the strong uplift of the chain; 3) the accommodation between compressional and extensional tectonic regimes along the Aeolian– Tindari–Letojanni faults, through a SSE–NNW right-lateral transtensional displacement. In these conditions, the greater and recurring uplift activity is not able to induce a radial extensional dynamics, but, under the “directing” action of the shear system, it can only act on the regional extension (NW–SE) and produce the second system of extension (NE–SW).
    Description: Published
    Description: 1-17
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Africa–Eurasia convergence ; Aeolian–Tindari fault system ; Transform activity ; Stress and strain fields ; Multidisciplinary approach ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 7
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    Subduction-triggered magmatic pulses: A new class of plumes? (2011)
    Elsevier
    Details
    Publication Date: 2021-01-27
    Description: A variety of atypical plume-like structures and focused upwellings that are not rooted in the lower mantle have recently been discussed, and seismological imaging has shown ubiquitous small-scale convection in the uppermost mantle in regions such as the Mediterranean region, the western US, and around the western Pacific. We argue that the three-dimensional return flow and slab fragmentation associated with complex oceanic subduction trajectories within the upper mantle can generate focused upwellings and that these may play a significant role in regional tectonics. The testable surface expressions of this process are the outsidearc alkaline volcanism, topographic swell, and low-velocity seismic anomalies associated with partial melt. Using three-dimensional, simplified numerical subduction models, we show that focused upwellings can be generated both ahead of the slab in the back-arc region (though ~five times further inward from the trench than arc-volcanism) and around the lateral edges of the slab (in the order of 100 km away from slab edges). Vertical mass transport, and by inference the associated decompression melting, in these regions appears strongly correlated with the interplay between relative trench motion and subduction velocities. The upward flux of material from the depths is expected to be most pronounced during the first phase of slab descent into the upper mantle or during slab fragmentation. We discuss representative case histories from the Pacific and the Mediterranean where we find possible evidence for such slab-related volcanism.
    Description: Published
    Description: 54-68
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: subduction ; magmatism ; upper mantle convection ; geodynamic modeling ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 8
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    Role of the brittle–ductile transition on fault activation (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2021-01-27
    Description: We model a fault cross-cutting the brittle upper crust and the ductile lower crust. In the brittle layer the fault is assumed to have stick–slip behaviour, whereas the lower ductile crust is inferred to deform in a steady-state shear. Therefore, the brittle–ductile transition (BDT) separates two layers with different strain rates and structural styles. This contrasting behaviour determines a stress gradient at the BDT that is eventually dissipated during the earthquake. During the interseismic period, along a normal fault it should form a dilated hinge at and above the BDT. Conversely, an over-compressed volume should rather develop above a thrust plane at the BDT. On a normal fault the earthquake is associated with the coseismic closure of the dilated fractures generated in the stretched hangingwall during the interseismic period. In addition to the shear stress overcoming the friction of the fault, the brittle fault moves when the weight of the hangingwall exceeds the strength of the dilated band above the BDT. On a thrust fault, the seismic event is instead associated with the sudden dilation of the previously over-compressed volume in the hangingwall above the BDT, a mechanism requiring much more energy because it acts against gravity. In both cases, the deeper the BDT, the larger the involved volume, and the bigger the related magnitude. We tested two scenarios with two examples from L’Aquila 2009 (Italy) and Chi-Chi 1999 (Taiwan) events. GPS data, energy dissipation and strain rate analysis support these contrasting evolutions. Our model also predicts, consistently with data, that the interseismic strain rate is lower along the fault segment more prone to seismic activation.
    Description: Published
    Description: 160-161
    Description: JCR Journal
    Description: open
    Keywords: faul activation ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 9
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    Magma-derived gas influx and water-rock interactions in the volcanic aquifer of Mt. Vesuvius, Italy (2005)
    Elsevier
    Details
    Publication Date: 2021-06-25
    Description: We report in this paper a systematic investigation of the chemical and isotopic composition of groundwaters flowing in the volcanic aquifer of Mt. Vesuvius during its current phase of dormancy, including the first data on dissolved helium isotope composition and tritium content. The relevant results on dissolved He and C presented in this paper reveal that an extensive interaction between rising magmatic volatiles and groundwaters currently takes place at Vesuvius. Vesuvius groundwaters are dilute (mean TDS 2800 mg/L) hypothermal fluids (mean T 17.7°C) with a prevalent alkaline-bicarbonate composition. Calcium-bicarbonate groundwaters normally occur on the surrounding Campanian Plain, likely recharged from the Apennines. D and 18O data evidence an essentially meteoric origin of Vesuvius groundwaters, the contribution from either Tyrrhenian seawater or 18O-enriched thermal water appearing to be small or negligible. However, the dissolution of CO2-rich gases at depth promotes acid alteration and isochemical leaching of the permeable volcanic rocks, which explains the generally low pH and high total carbon content of waters. Attainment of chemical equilibrium between the rock and the weathering solutions is prevented by commonly low temperature (10 to 28°C) and acid-reducing conditions. The chemical and isotope (C and He) composition of dissolved gases highlights the magmatic origin of the gas phase feeding the aquifer. We show that although the pristine magmatic composition may vary upon gas ascent because of either dilution by a soil-atmospheric component or fractionation processes during interaction with the aquifer, both 13C/12C and 3He/4He measurements indicate the contribution of a magmatic component with a 13C 0‰ and R/Ra of 2.7, which is consistent with data from Vesuvius fumaroles and phenocryst melt inclusions in olivine phenocrysts. A main control of tectonics on gas ascent is revealed by data presented in this paper. For example, two areas of high CO2 release and enhanced rock leaching are recognized on the western (Torre del Greco) and southwestern (Torre Annunziata–Pompeii) flanks of Vesuvius, where important NE-SW and NW-SE tectonic structures are recognized. In contrast, waters flowing through the northern sector of the volcano are generally colder, less saline, and CO2 depleted, despite in some cases containing significant concentrations of magmaderived helium. The remarkable differences among the various sectors of the volcano are reconciled in a geochemical interpretative model, which is consistent with recent structural and geophysical evidences on the structure of Somma-Vesuvius volcanic complex.
    Description: -European Union, -Ministero dell’Universita’ e della Ricerca Scientifica e Tecnologica; -CNR–Gruppo Nazionale per la Vulcanologia.
    Description: Published
    Description: 963–981
    Description: partially_open
    Keywords: isotopes ; water chemistry ; dissolved gases ; 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 ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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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
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  • 11
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    Mantle-derived carbon in Hercynian granites. Stable isotopes signatures and C/He associations in the thermomineral waters, N-Portugal (2010)
    Elsevier
    Details
    Publication Date: 2021-01-27
    Description: Na–HCO3–CO2-rich thermomineral waters issue in the N of Portugal, within the Galicia-Trás-os-Montes region, linked to a major NNE-trending fault, the so-called Penacova-Régua-Verin megalineament. Along this tectonic structure different occurrences of CO2-rich thermomineral waters are found: Chaves hot waters (67 °C) and also several cold (16.1 °C) CO2-rich waters. The δ2H and δ18O values of the thermomineral waters are similar to those of the local meteoric waters. The chemical composition of both hot and cold mineral waters suggests that water–rock reactions are mainly controlled by the amount of dissolved CO2 (g) rather than by the water temperature. Stable carbon isotope data indicate an external CO2 inorganic origin for the gas. δ13CCO2 values ranging between −7.2‰ and −5.1‰ are consistent with a two-component mixture between crustal and mantle-derived CO2. Such an assumption is supported by the 3He/4He ratios measured in the gas phase, are between 0.89 and 2.68 times the atmospheric ratio (Ra). These ratios which are higher than that those expected for a pure crustal origin (≈0.02 Ra), indicating that 10 to 30% of the He has originated from the upper mantle. Release of deep-seated fluids having a mantle-derived component in a region without recent volcanic activity indicates that extensive neo-tectonic structures originating during the Alpine Orogeny are still active (i.e., the Chaves Depression).
    Description: Published
    Description: 49-56
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: CO2-rich thermomineral waters ; mantle volatiles ; isotopes ; Chaves geothermal system ; N-Portugal ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 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::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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    Temporal trends and matrix-dependent behaviors of trace elements closed to a geothermal hot-spot source (Aeolian Archipelago, Italy) (2012)
    Elsevier
    Details
    Publication Date: 2021-04-07
    Description: Degassing activity from marine shallow-water hydrothermal vents represents a natural important source of trace elements of particular ecotoxicological concern, such as Hg, Cd, Pb, and As. In 2002, on November 3rd, a submarine area of the Aeolian Archipelago (Italy) was affected by an exceptional hydrothermal activity, presumably associated to a significant trace element release. This study developed in the highest impacted area, was focused on different environmental matrices (water, sediment, primary producers, and fishes) with the aim to evaluate on a statistical basis temporal dynamics involving trace elements closed to the emission source. Results evidenced that this event produced significant changes in water column, modifying the general assessment of the chemical descriptors selected (Na, K, Mg, Ca, Cl, Br, SO4 2-, HCO3 -). Furthermore, the degassing activity represents a significant input of Hg, Cd, Pb, and As for all of the sampled matrices, being it responsible of the higher levels observed in the study area compared to controls. Concentrations measured in sediments and biota (Cystoseira compressa, Serranus cabrilla) at temporal intervals of ten months distanced, supported the occurrence of different time scale dynamics which are both element and matrix-dependent. In particular, levels of Cd and As measured in liver tissues of S. cabrilla evidenced a significant trend to increase with the time, allowing to exclude a quick recovery of the study area. Measured values in edible fishes tissues are, also, notably higher than risk limits proposed by the 2001/22/CE Directive for human consumption, so, local-based caught have to be accurately regulated to avoid the occurrence of diet over-exposure.
    Description: Published
    Description: 10-28
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: N/A or not JCR
    Description: restricted
    Keywords: trace elements ; hydrothermal vents ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
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    Geochemical monitoring of groundwaters (1998-2001) at Vesuvius volcano (Italy) (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This work presents the results of hydrogeochemical studies carried out at Vesuvius during the period May 1998 - December 2001, mostly focusing on compositional time variations observed during this time. Based on their chemistry, groundwater samples are distinguished into two groups, 1 and 2, representative of water circulation in the southern and northern sectors of the volcano, respectively. Waters from group 1 are typically more acidic, warmer,and more saline than those of group 2. They also have higher CO2 and CH4 contents, attributed to enhanced input of deep-rising volatiles and prolonged water-rock interactions. Time-series highlight the fairly constant chemical composition of the entire aquifer. Groundwater temperature, pH, bicarbonate content and dissolved CO2 display quite stable values in the study period, particularly in deep wells (piezometric level more than 100 m deep). Shallower water bodies present more evident temporal variations, related to seasonal and anthropogenic effects. This paper also describes some important variations in water chemistry which had occurred by the time of the seismic event in early October 1999, particularly in the Olivella spring located on the northern flank of the volcano. At this site, a great decrease in water pH and redox potential, and increased dissolved CO2 contents and 3He/4He ratios were observed. These changes in chemical and isotope composition support the hypothesis of an input of magma-derived helium and carbon dioxide into the aquifer feeding the Olivella spring by the time of the earthquake.
    Description: Published
    Description: 81-104
    Description: partially_open
    Keywords: Vesuvius ; volcanic surveillance ; groundwater ; hydro-geochemistry ; oxygen-18 ; 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::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 14
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    Chemical and isotopic equilibrium between CO2 and CH4 in fumarolic gas discharges: generation of CH4 in magmatic-hydrothermal systems (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The chemical and isotopic composition of fumarolic gases emitted from Nisyros Volcano, Greece,and of a single gas sample from Vesuvio, Italy, was investigated in order to determine the origin of methane (CH4) within two subduction-related magmatic-hydrothermal environments. Apparent temperatures derived from carbon isotope partitioning between CH4 and CO2 of around 340°C for Nisyros and 470°C for Vesuvio correlate well with aquifer temperatures as measured directly and/or inferred from compositional data using the H2O-H2-CO2-CO-CH4 geothermometer. Thermodynamic modeling reveals chemical equilibrium between CH4, CO2 and H2O implying that carbon isotope partitioning between CO2 and CH4 in both systems is controlled by aquifer temperature. N2/3He and CH4/3He ratios of Nisyros fumarolic gases are unusually low for subduction zone gases and correspond to those of midoceanic ridge environments. Accordingly, CH4 may have been primarily generated through the reduction of CO2 by H2 in the absence of any organic matter following a Fischer-Tropsch-type reaction. However, primary occurrence of minor amounts of thermogenic CH4 and subsequent re-equilibration with co-existing CO2 cannot be ruled out entirely. CO2/3He ratios and 13CCO2 values imply that the evolved CO2 either derives from a metasomatized mantle or is a mixture between two components, one outgassing from an unaltered mantle and the other released by thermal breakdown of marine carbonates. The latter may contain traces of organic matter possibly decomposing to CH4 during thermometamorphism.
    Description: European community
    Description: Published
    Description: 2321–2334
    Description: partially_open
    Keywords: fumarolic gases ; hydrothermal systems ; chemical and isotopic equilibrium ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 15
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    Microbial communities near the oxic/anoxic interface in the hydrothermal system of Vulcano Island, Italy (2006)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Hydrothermal fluids and sediments from subaerial and shallow submarine sites at Vulcano Island, Italy were investigated for relations between the thermophilic microbial communities, as analysed by fluorescence in situ hybridization, and their geochemical environment, as assessed by photometry, chromatography, and in situ microsensor measurements. Mixing between hydrothermal fluids and seawater in the sediment pore space was reflected in the chemical composition of the emitted fluids, in depth profiles of pore water oxygen and sulfide concentrations, and in the structure of the benthic microbial community. Organic compounds did not accumulate in the vent fluids (b10 AM fatty acids) or in the sediments (b0.1% Corg), suggesting that efficient utilization supported microbial populations on the order of 104 cells per ml fluid and 108 cells per cm3 sediment. Groups of thermophiles that typically gain metabolic energy from the fermentation of organic matter (Thermococcales, Thermotoga/Thermosipho spp., and Bacillus sp.)were detected in significant abundances at all study sites. Also abundant were thermophiles capable of oxidizing organic acids with oxygen, nitrate, or sulfate. Aerobic thermophiles (Aquificales and Thermus sp.) were more abundant at oxic sites than at anoxic sites. Increasingly oxygenated habitats were associated with decreasing abundance of anaerobic (hyper)thermophiles belonging to the order Archaeoglobales.
    Description: Published
    Description: 169– 182
    Description: partially_open
    Keywords: Biogeochemistry ; Hydrothermal system ; Marine sediment ; Microbial ecology ; Microsensor ; Thermophiles ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
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  • 16
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    The 2004-05 Etna eruption: implications for flank deformation and structural behaviour of the volcano (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The development of the 2004–2005 eruption at Etna (Italy) is investigated by means of field surveys to define the current structural state of the volcano. In 2004–2005, a fracture swarm, associated with three effusive vents, propagated downslope from the SE summit crater towards the SE. Such a scenario is commonly observed at Etna, as a pressure increase within the central conduits induces the lateral propagation of most of the dikes downslope. Nevertheless, some unusual features of this eruption (slower propagation of fractures, lack of explosive activity and seismicity, oblique shear along the fractures) suggest a more complex triggering mechanism. A detailed review of the recent activity at Etna enables us to better define this possible mechanism. In fact, the NW–SE-trending fractures formed in 2004–2005 constitute the southeastern continuation of a N–S-trending fracture system which started to develop in early 1998 to the east of the summit craters. The overall 1998–2005 deformation pattern therefore forms an arcuate feature, whose geometry and kinematics are consistent with the head of a shallow flank deformation on the E summit of Etna. Similar deformation patterns have also been observed in analogue models of deforming volcanic cones. In this framework, the 2004–2005 eruption was possibly induced by a dike resulting from the intersection of this incipient fracture system with the SE Crater. A significant acceleration of this flank deformation may be induced by any magmatic involvement. The central conduit of the volcano is presently open, constantly buffering any increase in magmatic pressure and any hazardous consequence can be expected to be limited. A more hazardous scenario may be considered with a partial or total closing of the central conduit. In this case, magmatic overpressure within the central conduit may enhance the collapse of the upper eastern flank, triggering an explosive eruption associated with a landslide reaching the eastern lower slope of the volcano.
    Description: Published
    Description: 195–206
    Description: reserved
    Keywords: eruption triggering ; volcano-tectonics ; fracture fields ; flank spreading ; Mt. Etna ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 17
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    Slab detachment beneath eastern Anatolia: A possible cause for the formation of the North Anatolian fault (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In this paper, we discuss the possibility that the North Anatolian fault (NAF) results from the deep deformation of the slab beneath the Bitlis–Hellenic subduction zone. We described the tectonic evolution of the Anatolia–Aegean area in three main steps, before, during and after the formation of the NAF. We remark that the tectonic conditions that are assumed to have triggered the formation of the NAF, i.e. collision to the east and extension to the west, was already achieved before the onset of that strike-slip fault system. We also highlight that the formation of the NAF was accompanied by the uplift of the Turkish–Iranian plateau and by a surge of volcanism in the eastern Anatolia collisional area and probably by the acceleration of the Aegean trench retreat. We show tomographic images from global P-wave model of Piromallo and Morelli [C. Piromallo, A. Morelli, P wave tomography of the mantle under the Alpine–Mediterranean area, J. Geophys. Res. 108 (2003) doi: 10.1029/2002JB001757.] showing that the slab beneath the Bitlis collisional belt is not continuous and that its possible rupture pursues to the west at least up to Cyprus and possibly up to the eastern end of the Hellenic trench. All these observations suggest that the plate tectonic re-organization occurred in the Late Miocene–Early Pliocene in the region results from slab break-off in the Bitlis area and from its lateral propagation to the West. This idea is tested in analogue laboratory experiments, which confirm that the break of the slab under the collisional belt may trigger, (1) the acceleration of slab retreat to the west due to the increase in slab pull force, (2) the indentation of the continent in the collisional area and (3) produce the conditions that permit the lateral escape of material towards the west and the formation of the NAF.
    Description: Published
    Description: 85-97
    Description: JCR Journal
    Description: reserved
    Keywords: Mediterranean ; subduction ; collision ; analogue experiments ; seismic tomography ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 18
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    Geodynamic implications of deep mantle upwelling in the source of Tertiary volcanics from the Veneto region (South-Eastern Alps) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Major and trace element and Sr–Nd–Hf–Pb isotopic data for the most primitive Tertiary lavas from the Veneto region (South-Eastern Alps, Italy) show the typical features of HIMU hotspot volcanism, variably diluted by a depleted asthenospheric mantle component (87Sr/86Sri=0.70306–0.70378; "Ndi=+3.9 to +6.8; "Hfi=+6.4 to +8.1, 206Pb/204Pbi=18.786–19.574). P-wave seismic tomography of the mantle below the Veneto region shows the presence of low-velocity anomalies at depth, which is consistent with possible upwellings of plume material. Between the depths of 100–250 km the velocity anomalies are approximately 2–2.5% slower than average, implying a temperature excess of about 220–280 K, in agreement with estimates for other mantle plumes in the world. In this context, the Veneto volcanics may represent the shallow expression of a mantle upflow. The presence of a HIMU-DM component in a collision environment has significant geodynamic implications. Slab detachment and ensuing rise of deep mantle material into the lithospheric gap is proposed to be a viable mechanism of hotspot magmatism in a subduction zone setting.
    Description: Published
    Description: 563–590
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: trace-element ; isotopic composition ; alkali basalts ; central-Europe ; slab break-off ; plume ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 19
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    A late Cretaceous contamination episode of the European–Mediterranean mantle (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: One of the most challenging issues about the Tertiary–Quaternary alkaline magmatism spreading across the Euro-Mediterranean region is the assessment of both the nature of its mantle source and the mechanism responsible for the common HIMU-like (High μ=high 238U/204Pb) character of erupted lavas, enduring over about 100 million years in diverse tectonic environments. In this paper we try to reconcile geochemical and geophysical data through a multidisciplinary investigation on geochemistry, timing and locations of the main Na-rich alkaline volcanic centers, seismic tomographic images and plate kinematics. We propose that the common component of the Euro-Mediterranean mantle derives from a contamination episode triggered by the rise of the Central Atlantic Plume (CAP) head. Plate reconstruction shows that at late Cretaceous- Paleocene time the oldest magmatic centers of the Euro-Mediterranean region were located more than 2000 km SW of their present day position, in proximity of the CAP hot spot location, where seismic tomography detects a broad low seismic velocity region in the lower mantle. The northeastward migration of the Eurasian and African plates could have involved also part of the CAP contaminated mantle, which moved in the same direction being coupled to the lithospheric plates, thus explaining the presence of geochemically-uniform material spread in the sub-lithospheric Euro-Mediterranean mantle. During the Tertiary, regional-scale convection and related processes such as rifting, back-arc spreading, slab detachment/windows, may have favored upwelling and partial melting of the frayed plume head material via adiabatic decompression, shaping the spatial and temporal distribution of HIMU-like volcanics. The growing supply of subducted lithosphere may explain as well the increase of crustal isotopic signatures of alkaline magmas with time. In our opinion, the Euro-Mediterranean upper mantle contamination can be eventually related to a global event occurred during the Cretaceous as a consequence of a mantle avalanche caused by the Tethys closure.
    Description: MIUR 2005-2007, prot. n. 2005055415_002, Poli G.
    Description: Published
    Description: 15–27
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: partially_open
    Keywords: Cenozoic HIMU–OIB volcanism ; Euro-Mediterranean mantle ; geochemistry ; mantle tomography ; plate kinematics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 20
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    Subduction polarity reversal at the junction between the Western Alps and the Northern Apennines, Italy (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The controversial relationship between the orogenic segments of the Western Alps and the Northern Apennines is here explored integrating recently published 3D tomographic models of subduction with new and re-interpreted geological observations from the eclogitic domain of the Voltri Massif (Ligurian Alps, Italy), where the two belts joint each other. The Voltri Massif is here described as an extensional domain accommodating the opposing outward migration of the Alpine and Apennine thrust fronts, since about 30–35 Ma. Using tomographic images of the upper mantle and paleotectonic reconstructions, we propose that this extensional setting represents the surface manifestation of an along strike change in polarity of the subducted oceanic slab whose polarity changed laterally in space and in time. Our tectonic model suggests that the westward shift of the Alpine thrust front from the Oligocene onward was the consequence of the toroidal asthenospheric flow induced by the retreat of the Apenninic slab.
    Description: Published
    Description: 34–50
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Western Alps ; Northern Apennines ; Voltri Massif ; Tomography ; Kinematic reconstruction ; Extensional detachment ; Toroidal flow ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 21
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    Paleomagnetic constraints on the Plio-Pleistocene geodynamic evolution of the external central-northern Apennines (Italy) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We report on new paleomagnetic results obtained from 27 sites sampled in the Plio-Pleistocene sequences at the external front of the central-northern Apennines. Previous analyses of Miocene (Messinian) sediments indicated that the present shape of the northern Apenninic arc is due to the oroclinal bending of an originally straight belt oriented around N320° and that vertical axis rotations accompanied the migration of the thrust fronts toward the Adriatic foreland [F. Speranza et al., J. Geophys. Res. 102 (1997) 3153-3166]. We tried to provide new paleomagnetic constraints for the timing and rates of the oroclinal bending process during the Pliocene and the Pleistocene. The results suggest that CCW rotations observed in the northern part of the studied area are possibly younger than 3 Ma. No regional rotation is recorded in the Pliocene and Pleistocene sediments from the southern part of the study area, analogously to the Messinian sediments of the 'Acquasanta' domain of Speranza et al. [F. Speranza et al., J. Geophys. Res. 102 (1997) 3153-3166]. A local significant CCW rotation (23° ± 10°) is identified in the Early Pleistocene sediments that crop out along the Adriatic coast between Ascoli and Pescara, indicating differential motion of the thrust sheets. This rotation must be younger than 1.43 Ma.
    Description: Published
    Description: 243-257
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: open
    Keywords: paleomagnetism ; Apennines ; tectonics ; Pliocene ; Pleistocene ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 22
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    Invited reply to the Comment on: “Geomorphological, paleontological and 87Sr/86Sr isotope analyses on early Pleistocene paleoshorelines to define the uplift of Central Apennines (Italy)” (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Invited reply to the Comment on: “Geomorphological, paleontological and 87Sr/86Sr isotope analyses on early Pleistocene paleoshorelines to define the uplift of Central Apennines (Italy)”
    Description: In response to the comment of Cosentino and Fubelli (2007) on the stratigraphy of the Middle Valley of Tiber River basin (MVT) and on the chronological attribution of the uppermost paleoshorelines (UPS), we recall that we performed a detailed sampling campaign to date the youngest marine deposits underlying or laterally related to the UPS, through the 87Sr/86Sr method. Unfortunately, we cannot have taken advantage from the new stratigraphic data of the comment, being that all these data are still unpublished. On the sections presented in the comment, which concern only the southernmost tract of the UPS alignment, we do not know exactly how close these sections are to the UPS and how accurate the stratigraphic relationships are. This is due to the absence in the comment of detailed geographic locations of sections and of any stratigraphic scheme or geological map that might help link the data presented in Mancini et al. (2007) with the new ones. In general, the age of the new proposed sections are considered older (Gelasian) than our age estimate (1.65–1.50 Ma, i.e. late Santernian) for the UPS.
    Description: Published
    Description: 165-167
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Early Pleistocene ; shoreline ; uplift ; Apennines ; Sr isotope ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
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  • 23
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    New GPS constraints on the kinematics of the Apennines subduction (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We present the velocity field of the Italian area derived from continuous GPS observations from 2003 to 2007. The GPS sites were installed by different institutions and for different purposes; they cover the whole country with a mean inter-site distance of about 60 km and provide a valuable source of data to map the present day kinematics of the region. The absolute ITRF2005 rotation poles and rates of Eurasia, Africa and Adriatic plates are estimated, to study the kinematics along their boundaries in the Apennines belt. The Corsica–Sardinia block, coherently moving as the Eurasia plate, is used as reference of the upper plate for the Apennines subduction zone.We apply a simple kinematic model to estimate the rates and spatial pattern of the subduction along the Apennines. We identify at least four different, independently moving, lower plates, i.e., the Adriatic (diverging and internally segmented), Ionian, Sicily and Africa (converging) plates with different subduction rates. The conservative estimates of the subduction rate are ~5 mm/yr in the Calabrian Arc, ~1.5 mm/yr in Sicily, and ~0.9 mm/yr in the northern Apennines. This variegate mixture of behaviors seems to reflect the variable lithospheric thickness and composition of the lower plates inherited from the Mesozoic rifting. An unexpected along strike contraction is observed along the western side of the central-northern Apennines. Velocities are estimated both relative to Eurasia, and relative to the deep and shallow hotspot reference frames (HSRF). The hotspot representation seems more coherent with the geophysical and geological constraints along the subduction system, in which the Adriatic and Ionian plates move SW-ward and their deeper slab portions provide an obstacle to the opposite relative mantle flow. All these patterns better reconcile if the subduction process is conceived as a passive feature controlled by the far field plate velocities and the relative “eastward” mantle flow acting on a disrupted slab.
    Description: Published
    Description: 163-174
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: GPS ; ITRF2005 ; Adriatic ; Eurasia ; Africa ; Euler poles ; Apennines ; slab kinematics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics
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  • 24
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    The Albano Maar Lake high resolution bathymetry and dissolved CO2 budget (Colli Albani volcano, Italy): Constrains to hazard evaluation (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Albano Lake is the deepest volcanic lake in Italy (−167 m) and fills the youngest maar of the quiescent Colli Albani volcano. The lake has undergone significant level changes and lahar generating overflows occurred about 5800 yrs B.P. and likely in 398 b.C., when Romans excavated a tunnel drain through the maar wall. Hazardous lake rollovers and CO2 release are still possible because the Albano volcano shows active ground deformation, gas emission and periodic seismic swarms. On November 2005, the first high resolution bathymetric survey of the Albano Lake was performed. Here we present the results provided by a Digital Elevation Model and 2-D and 3-D images of the crater lake floor, which is made by coalescent and partly overlapping craters and wide flat surfaces separated by some evident scarps. Submerged shorelines are identified at depths between −20 m and −41 m and indicate the occurrence of significant lake level changes, likely between 7.1 and 4.1 ka. The current lake volume is ~447.5×106 m3 and the total quantity of dissolved CO2 is 6850 t estimated by chemical analyses of samples collected on May 2006. A decrease of nearly one order of magnitude of the CO2 dissolved in the lake water below −120 m, observed from December 1997 to May 2006 (from 4190 to 465 t respectively), has been attributed to lake water overturn. The observed oscillations of the dissolved CO2 concentrations justify the efforts of monitoring the chemical and physical characteristics of the lake. At present the quantity of dissolved CO2 is very far from saturation and Nyostype events cannot presently occur.
    Description: DPC-INGV Project V3_1
    Description: Published
    Description: 258–268
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Albano maar ; lake bathymetry ; geochemistry ; crater lake hazard ; 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::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 25
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    SKS splitting in Southern Italy: anisotropy variations in a fragmented subduction zone. (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In this paper we present a collection of good quality shear wave splitting measurements in Southern Italy. In addition to a large amount of previous splitting measurements, we present new data from 15 teleseisms recorded from 2003 to 2006 at the 40 stations of the CAT/SCAN temporary network. These new measurements provide additional constraints on the anisotropic behaviour of the study region and better define the fast directions in the southern part of the Apulian Platform. For our analysis we have selected wellrecorded SKS phases and we have used the method of Silver and Chan to obtain the splitting parameters: the azimuth of the fast polarized shear wave (φ) and delay time (δt). Shear wave splitting results reveal the presence of a strong seismic anisotropy in the subduction system below the region. Three different geological and geodynamic regions are characterized by different anisotropic parameters. The Calabrian Arc domain has fast directions oriented NNE–SSW and the Southern Apennines domain has fast directions oriented NNW–SSE. This rotation of fast axes, following the arcuate shape of the slab, is marked by a lack of resolved measurements which occurs at the transition zone between those two domains. The third domain is identified in the Apulian Platform: here fast directions are oriented almost N–S in the northern part and NNE–SSW to ENE–WSW in the southern one. The large number of splitting parameters evaluated for events coming from different back-azimuth allows us to hypothesize the presence of a depth-dependent anisotropic structure which should be more complicated than a simple 2 layer model below the Southern Apennines and the Calabrian Arc domains and to constrain at 50 km depth the upper limit of the anisotropic layer, at least at the edge of Southern Apennines and Apulian Platform. We interpret the variability in fast directions as related to the fragmented subduction system in the mantle of this region. The trench-parallel φ observed in Calabrian Arc and in Southern Apennines has its main source in the asthenospheric flow below the slab likely due to the pressure induced by the retrograde motion of the slab itself. The pattern of φ in the Apulian Platform does not appear to be the direct result of the rollback motion of the slab, whose influence is limited to about 100 km from the slab. The anisotropy in the Apulian Platform may be related to an asthenospheric flow deflected by the complicated structure of the Adriatic microplate or may also be explained as frozen-in lithospheric anisotropy.
    Description: Published
    Description: 49-67
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: partially_open
    Keywords: Shear wave splitting ; Subduction ; Mantle flow ; Southern Italy ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes
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  • 26
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    The aquatic geochemistry of arsenic in volcanic groundwaters from southern Italy (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper discusses the abundance, speciation and mobility of As in groundwater systems from active volcanic areas in Italy. Using literature data and new additional determinations, the main geochemical processes controlling the fate of As during gas–water–rock interaction in these systems are examined. Arsenic concentrations in the fluids range from 0.1 to 6940 mg/l, with wide differences observed among the different volcanoes and within each area. The dependence of As content on water temperature, pH, redox potential and major ions is investigated. Results demonstrate that As concentrations are highest where active hydrothermal circulation takes place at shallow levels, i.e. at Vulcano Island and the Phlegrean Fields. In both areas the dissolution of As-bearing sulphides is likely to be the main source of As. Mature Cl-rich groundwaters, representative of the discharge from the deep thermal reservoirs, are typically enriched in As with respect to SO4-rich ‘‘steam heated groundwaters’’. In the HCO3 groundwaters recovered at Vesuvius and Etna, aqueous As cycling is limited by the absence of high-temperature interactions and by high-Fe content of the host rocks, resulting in oxidative As adsorption. Thermodynamic modelling suggests that reducing H2S-rich groundwaters are in equilibrium with realgar, whereas in oxidising environments over-saturation with respect to Fe oxyhydroxides is indicated. Under these oxidising conditions, As solubility decreases controlled by As co-precipitation with, or adsorption on, Fe oxy-hydroxides. Consistent with thermodynamic considerations, As mobility in the studied areas is enhanced in intermediate redox environments, where both sulphides and Fe hydroxides are unstable.
    Description: Published
    Description: 1283–1296
    Description: partially_open
    Keywords: Hydrogeochemistry ; Arsenic ; volcanic groundwaters ; speciation ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 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::03.04.06. Hydrothermal systems
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 27
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    Early Paleozoic evolution of the NW Gondwanaland: data from southern Turkey and surrounding regions (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The Lower Paleozoic assemblages in the E. Meditterranean comprise a Southern (Tauride-Anatolide,SE Anatolia and Central Iranian terranes) and a Northern (Carpathian-Balkan, Istanbul, Zonguldak and the Main Range terranes) Zone. A detailed stratigrapic account is given for these terranes for the Early Paleozoic and their paleogeographical settings are discussed to evaluate the Early Paleozoic geodynamic interpretation of this critical area between Gondwana-Perigondwana and Laurussia..
    Description: Published
    Description: 315-323
    Description: JCR Journal
    Description: open
    Keywords: Palaeozoic, evolution, Turkey ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 28
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    Seismic anisotropy beneath the Northern Apennines (Italy): Mantle flow or lithosphere fabric? (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Shear-wave splitting estimates from recordings of 10 portable seismographic stations during the first year of the RETREAT seismic deployment, in combination with broadband data from the Italian national seismic network, are associated with seismic anisotropy within the upper mantle beneath the Northern Apennines. Anisotropic parameters derived from both shear-wave splitting and P travel-time residuals vary geographically and depend on event back-azimuth, reflecting complexity in the underlying mantle strain field. Variations of the splitting time delays and fast polarization seem to exclude a 2-D sublithosphere corner flow, associated with the Apennines subduction, as the main source of the inferred anisotropy. The anisotropic signal may be generated by a frozen-in fabric of the Adriatic and Tyrrhenian lithosphere domains, or by flow variations induced by episodic and fragmentary slab rollback.
    Description: Published
    Description: 157-170
    Description: JCR Journal
    Description: reserved
    Keywords: birefringence; ; Apennines ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes
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  • 29
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    Sea-level change during the Holocene in Sardinia and in the northeastern Adriatic (central Mediterranean Sea) from archaeological and geomorphological data (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We provide new data on relative sea-level change from the late Holocene for two locations in the central Mediterranean: Sardinia and NE Adriatico. They are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea-level elevation. Twelve submerged archaeological sites were studied: six, aged between 2.5 and 1.6 ka BP, located along the Sardinia coast, and a further six, dated 2.0 ka BP, located along the NE Adriatic coast (Italy, Slovenia and Croatia). For Sardinia, we also use beach rock and core data that can be related to Holocene sea level. The elevations of selected significant archaeological markers were measured with respect to the present sea level, applying corrections for tide and atmospheric pressure values at the time of surveys. The interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea; these data are compared with predictions derived from a new glacio–hydro-isostatic model associated with the Last Glacial cycle. Sardinia is tectonically relatively stable and we use the sea-level data from this island to calibrate our models for eustatic and glacio–hydro-isostatic change. The results are consistent with those from another tectonically stable site, the Versilia Plain of Italy. The northeast Adriatic (Italy, Slovenia and Croatia) is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions. This indicates that the Adriatic coast from the Gulf of Trieste to the southern end of Istria has Q1 tectonically subsided by 1.5m since Roman times.
    Description: Published
    Description: 2463-2486
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: sea level, archaeology, tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 30
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    Belt bending driven by lateral bending of subducting lithospheric slab: geophysical evidences from the northern Apennines (Italy) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Many of the mountain belts displaying a curved shape are "oroclines", i.e. are produced after progressive bending of an originally straight fold and thrust belt. The bending process was previously explained as a consequence of several possible events taking place in the crustal orogenic wedge, such as occurrence of obstacles, non-coaxial deformation, and mouvements on wrench faults. Recent paleomagnetic results from the northern Apenninic Arc document that this belt is properly an orocline and results from Late Messinian-Early Pliocene bending of a Messinian straight belt-foredeep system. Tomographic images in turn show the presence of a high-velocity body, interpreted as subducted slab, in the upper mantle beneath the northern Apennines, between 35 and 670 km depth. Down to 100 km, this body displays an arcuate shape which closely mirrors the geological outlines, while it appears to be straight (and parallel to the Messinian pre-rotated belt) at depth. We explore here the possibility that the arcuate shape of the northern Apennines is a consequence, closely following in time, on much deeper processes than previously suggested, i.e. the lateral bending of the subducting Adriatic plate.
    Description: Published
    Description: 53-64
    Description: JCR Journal
    Description: reserved
    Keywords: paleomagnetism ; seismic tomography ; Northern Apennines ; orocline ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 31
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    Intrusion of eccentric dikes: The case of the 2001 eruption and its role in the dynamics of Mt. Etna volcano (2008)
    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 dynamic 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 reveal 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: In press
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    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: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: Stress release ; Dike ; Volcano-tectonics ; Flank instability ; Mount 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::04.03.06. Measurements and monitoring ; 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::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. 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::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 32
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    Hydrothermal Fluid Circulation and its Effect on Caldera Unrest (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.
    Description: Published
    Description: 393-416
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: reserved
    Keywords: hydrothermal fluids ; unrest ; modeling ; caldera ; monitoring ; volcanic hazard ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
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    Seismicity in Central and Northern Apennines integrating the Italian national and regional networks (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In this paper we present and discuss an improved picture of the seismicity distribution of the Umbria– Marche–Abruzzi Apennines as obtained through the integration of the national and the regional seismic networks operating from 2002 to 2006. During this period, both the Istituto Nazionale di Geofisica e Vulcanologia (INGV) National Seismic Network and the regional networks have been greatly improved. We compare the results of the integrated catalogue obtained in this study with the Catalogue of the Italian Seismicity between 1981 and 2001 [Castello, B., Selvaggi, G., Chiarabba, C., Amato, A., 2006. CSI Catalogo della sismicità italiana 1981–2002, versione 1.1. INGV-CNT, Roma.http://legacy.ingv.it/CSI )], confirming the basic known features of the seismic activity in the region, but also evidencing some original and interesting results. In particular, the new data set allows us to better define the geometry and kinematics of the crustal seismicity, which is confined to the upper 20 km and shows a clear general deepening from west to east. In the crust, we find additional evidence of extensional seismicity below the central portion of the belt and thrust/reverse faulting mechanisms at the outer fronts of the Apennines. Looking at the seismicity along the belt, it is also possible to observe aseismic regions, which could be due to either locked or creeping portions of the Apenninic fault system. At greater depth, the west-dipping seismicity distribution down to about 70 km confirms the hypothesis of a slab of Adriatic lithosphere subducted below the Apennines, but also suggests that there are strong lateral heterogeneities and possibly tears in the slab.
    Description: Published
    Description: 121-135
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Seismicity ; Seismic monitoring ; Focal mechanisms ; Subduction ; Apennines ; Italy ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
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  • 34
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    Active stress in the NE external margin of the Apennines: the Ferrara arc, northern Italy (2007)
    Elsevier
    Details
    Publication Date: 2012-02-03
    Description: We have analysed borehole breakout data from 12 deep wells in order to constrain the direction of the minimum and maximum horizontal stress in a part of the Po Plain, northern Italy, characterised by a N–S prevailing compressional stress regime, and in order to shed light on the regional state of stress and on the correlation between the active stress field and the orientation of tectonic structures. The results have been compared with seismological data relating to 1988–1995 crustal seismicity (2.5〈Md〈4.8) and to the 1983 Parma (Ms=5.0) and the 1996 Reggio Emilia (Ms=5.1) events. Plio-Pleistocene mesostructural data are also described in order to better define the present-day stress field and to understand the active tectonic processes in particular stress provinces. The borehole breakout analysis, in accordance with the seismicity and mesostructural data, shows the presence of a predominant compression area, characterised by approximately N–S maximum horizontal stress, along the outer thrust of the Ferrara arc. Particularly, the breakout analysis indicates a minimum horizontal stress, N81W±22° relative to a total of eleven analysed wells, with 3746 m cumulative total length of breakout zones. Among these, nine wells are located in the same tectonic structure, consisting of an arc of asymmetric folds overthrust towards the NE. The breakout results for these wells are quite similar in terms of minimum horizontal stress direction (E–W oriented). The other two wells are located in the outside sector of the arc and one of them shows a different minimum horizontal stress direction, probably distinctive of another tectonic unit. On the basis of these new reliable stress indicators, the active compressive front in this area is located along the termination of the external northern Apenninic arc.
    Description: Published
    Description: 251-265
    Description: reserved
    Keywords: stress ; borehole breakout ; tectonics ; Italy ; Apennines ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress
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  • 35
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    P-wave propagation heterogeneity and earthquake location in the Mediterranean region (2008)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2012-02-03
    Description: We analyse P-wave traveltimes for the Mediterranean area, using both teleseismic and regional arrivals for shallow earthquakes reported in the Bulletins of the International Seismological Centre. We model delays between pairs of 0.5° × 0.5° cells, obtaining a detailed representation of the P traveltime heterogeneities. Examination of these anomalies shows the clear presence of geographically coherent patterns—consistent with known geological features—due to significant structure in the upper mantle. We present a scheme, based on an empirical heterogeneity correction (EHC) to P-wave traveltimes, to improve earthquake location. This method provides similar benefits to those of a location procedure based on ray tracing in a 3-D model, but it is simpler and computationally more efficient. The definition of the traveltime heterogeneity model, being based on a statistical procedure, bypasses most of the critical points and possible instabilities involved in model inversion. EHC relocation, applied to Mediterranean earthquakes, allows one to predict about 70 per cent of the estimated signal due to heterogeneity and produces epicentral and origin time-shifts of, respectively, 4.22 km and 0.35 s (rms). From a synthetic experiment, in which we use the proposed algorithm to retrieve known source locations, we estimate that the rms improvement achieved by the EHC relocation over a simpler, standard, 1-D location is more than 20 per cent for both epicentral mislocation and origin time-shifts.
    Description: Published
    Description: 232-254
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: earthquake location ; Mediterranean ; P waves ; traveltime ; upper mantle ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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    The buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This survey proposes a new approach to identify buried caldera boundaries of a volcanic cone, combining (1) a systematic elliptic Fourier functions (EFF) analysis on the contour lines based on the external shape of the edifice with (2) self-potential (SP) measurements on volcano flanks. The methodology of this approach is to investigate the relationships between (1) vertical morphological changes inferred from EFF analysis and (2) lateral lithological transition inside the edifice inferred from SP/elevation gradients. The application of these methods on Misti volcano in southern Peru displays a very good correlation. The three main boundaries evidenced by hierarchical cluster analysis on the contour lines coincide with the two main boundaries characterised by SP signal and with a secondary SP signature related with a summit caldera. In order to explain these results showing a very good correlation between morphologic and lithologic changes as function of elevation, caldera boundaries have been suggested. The latter would be located at an average elevation of (1) 4350–4400 m, (2) 4950–5000 m, and (3) 5500– 5550 m. For the lowest boundary in elevation, the coincidence with the lateral extension of the hydrothermal system inferred from SP measurements suggests that caldera walls act as a barrier for lateral extension of hydrothermal systems. In the summit area, the highest boundary has been related with the summit caldera, inferred by a secondary SP minimum and geological evidence.
    Description: - Institut de Recherche pour le Développement (IRD) - Instituto Geofisico del Peru´ (IGP).
    Description: Published
    Description: 283– 297
    Description: partially_open
    Keywords: caldera ; elliptic Fourier functions ; geomorphology ; self-potential ; Misti volcano ; Peru ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 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::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 37
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    Fluid circulation at Stromboli volcano (Aeolian Islands, Italy) from self-potential and CO2 surveys (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This work addresses the study of fluid circulation of the Stromboli island using a dense coverage of self-potential (SP) and soil CO2 data. A marked difference exists between the northern flank and the other flanks of the island. The northern flank exhibits (1) a typical negative SP/altitude gradient not observed on the other flanks, and (2) higher levels of CO2. The general SP pattern suggests that the northern flank is composed of porous layers through which vadose water flows down to a basal water table, in contrast to the other flanks where impermeable layers impede the vertical flow of vadose water. In the Sciara del Fuoco and Rina Grande-Le Schicciole landslide complexes, breccias of shallow gliding planes may constitute such impermeable layers whereas elsewhere, poorly permeable, fine-grained pyroclastites or altered lava flows may be present. This general model of the flanks also explains the main CO2 patterns: concentration of CO2 at the surface is high on the porous north flank and lower on the other flanks where impermeable layers can block the upward CO2 flux. The active upper part of the island is underlain by a well-defined hydrothermal system bounded by short-wavelength negative SP anomalies and high peaks of CO2. These boundaries coincide with faults limiting ancient collapses of calderas, craters and flank landslides. The hydrothermal system is not homogeneous but composed of three main subsystems and of a fourth minor one and is not centered on the active craters. The latter are located near its border. This divergence between the location of the active craters and the extent of the hydrothermal system suggests that the internal heat sources may not be limited to sources below the active craters. If the heat source strictly corresponds to intrusions at depth around the active conduits, the geometry of the hydrothermal subsystems must be strongly controlled by heterogeneities within the edifice such as craters, caldera walls or gliding planes of flank collapse, as suggested by the correspondence between SP^CO2 anomalies and structural limits. The inner zone of the hydrothermal subsystems is characterized by positive SP anomalies, indicating upward movements of fluids, and by very low values of CO2 emanation. This pattern suggests that the hydrothermal zone becomes self-sealed at depth, thus creating a barrier to the CO2 flux. In this hypothesis, the observed hydrothermal system is a shallow one and it involves mostly convection of infiltrated meteoric water above the sealed zone. Finally, on the base of CO2 degassing measurements, we present evidence for the presence of two regional faults, oriented N41‡ and N64‡, and decoupled from the volcanic structures.
    Description: Published
    Description: 1^18
    Description: partially_open
    Keywords: Stromboli ; hydrothermal system ; self-potential ; soil gas ; carbon dioxide ; Aeolian islands ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 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 ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 38
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    Mineral control of arsenic content in thermal waters from volcano-hosted hydrothermal systems: insights from island of Ischia and Phlegrean Fields (Campanian Volcanic Province, Italy) (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper documents arsenic concentrations in 157 groundwater samples from the island of Ischia and the Phlegrean Fields, two of the most active volcano-hosted hydrothermal systems from the Campanian Volcanic Province (Southern Italy), in an attempt to identify the environmental conditions and mineral-solution reactions governing arsenic aqueous cycling. On Ischia and in the Phlegrean Fields, groundwaters range in composition from NaCl brines, which we interpret as the surface discharge of deep reservoir fluids, to shallow-depth circulating fluids, the latter ranging from acid-sulphate steam-heated to hypothermal, cold, bicarbonate groundwaters. Arsenic concentrations range from 1.6 to 6900 μg·l−1 and from 2.6 to 3800 μg·l−1 in the Phlegrean Fields and on Ischia, respectively. They increase with increasing water temperature and chlorine contents, and in the sequence bicarbonate groundwatersbsteam-heated groundwatersbNaCl brines. According to thermochemical modeling, we propose that high As concentrations in NaCl brines form after prolonged water–rock interactions at reservoir T, fO2 and fH2S conditions, and under the buffering action of an arsenopyrite+pyrite+pyrrhotite rock assemblage. On their ascent toward the surface, NaCl brines become diluted by As-depleted meteoric-derived bicarbonate groundwaters, giving rise to hybrid water types with intermediate to low As contents. Steam-heated groundwaters give their intermediate to high As concentrations to extensive rock leaching promoted by interaction with As-bearing hydrothermal steam.
    Description: Published
    Description: 313–330
    Description: reserved
    Keywords: Arsenic geochemistry ; Hydrothermal systems ; Water–rock interaction ; Hydrogeochemistry ; Arsenopyrite ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
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  • 39
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    The role of pre-existing thrust faults and topography on the styles of extension in the Gran Sasso range (central Italy) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Structural analysis and field mapping together with simple geometrical and flexural elastic models, document that two styles of Quaternary extensional tectonics characterized the Gran Sasso range (central Apennines, Italy). In the western part of the range, extension took place on 10–15-km-long range-front normal faults with associated 600–1000-m-high escarpments showing evidence of Late Glacial–Holocene activity. This topography has been reproduced with a thin elastic plate subjected to the isostatic forces induced by the movement along high-angle (55°–65°) planar normal faults. In the eastern part of the belt extension occurred on shallow-dipping normal faults (30°–35°) which reactivated progressively deeper pre-existing thrusts. In this area antithetic "domino" faults formed to accommodate the mechanical adjustment of the hanging-wall over a variably dipping major fault surface. The eastward increase in shortening, due to the earlier compressional phase, documented in the Gran Sasso belt by previous authors, accounts for the more developed zones of weakness and high topographic relief in the eastern sector. This setting could explain the different styles of extension and the more advanced northeastern limit of normal faulting in the eastern sector. This work suggests that normal faults can originate either with low- or high-angle geometry in the upper crust according to the pre-existing tectonic setting and that topography could be important in controlling the geometry and pattern of migrating normal faulting.
    Description: Published
    Description: 229-254
    Description: JCR Journal
    Description: reserved
    Keywords: extensional tectonics ; Quaternary ; thrust faults ; topography ; Apennines ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 40
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    Seismic activity in the transition zone between Southern and Central Apennines (Italy): Evidences of longitudinal extension inside the Ortona–Roccamonfina tectonic line (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We analyze the 1997–2006 seismicity of the transition zone between Southern and Central Apennines, which is one of the most active seismic areas of Italy. Our aim is to add information on the seismotectonic picture of this area. Seismic activity is characterized by single events with Mb3.0 and low magnitude (Mb4.0) seismic sequences (1997–98 and 2005) and swarms (1999, 2000 and 2001). Hypocenters are within the upper 15 km of the crust. The epicentral distribution of the relocated seismicity shows that single events prevalently align NW–SE along the Apennine chain axis. This seismicity is related to the main, NE–SW extension affecting the chain. Single events concentrate also: at the south of the seismogenetic source responsible for the 1915 earthquake, where the 2000 swarm occurred; between the faults of the 1984 and 1805 events, where the 2001 sequence developed; between the faults of the 1805 and 1688 events, where the 1997–1998 seismic sequence concentrated. The seismic swarms occurred in 1999, 2000 and 2005 are located inside the Ortona– Roccamonfina structural line, which strikes NNE–SSW and separates the Central Apennines from the Southern ones. The epicentral distribution of these swarms and focal mechanisms suggest the presence of active NE–SW faults moving in response to a NW–SE extension. The results of the strain analysis on 52 wellconstrained focal mechanisms evidence a prevailing NE–SW extension, corresponding to the large scale stress field acting in the Apennine Chain, and a second-order NW–SE extension. This last direction of extension was already observed in the 1997–98 and 2001 seismic sequences. The location of the NE–SW striking faults responsible for the seismic swarms suggest that some segments of the Ortona–Roccamonfina line are still active and move in response to both the NE–SW regional extension of Southern Apennines, and to a NW–SE striking longitudinal extension.
    Description: Published
    Description: 102-110
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 3.1. Fisica dei terremoti
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Apennines ; seismicity ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
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  • 41
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    Methana, the westernmost active volcanic system of the south Aegean arc (Greece): insight from fluids geochemistry (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: An extensive geochemical survey of the fluids released by the volcanic/geothermal system of Methana was undertaken. Gases were characterized based on the chemical and isotopic [helium (He) and carbon (C)] analysis of 27 samples. Carbon dioxide soil gas concentration and fluxes were measured at 179 sampling sites throughout the peninsula. Forty samples of thermal and cold groundwaters were also sampled and analysed to characterize the geochemistry of the aquifers. Gases of hydrothermal origin gave a preliminary geothermometric estimate of about 210 °C. The He-isotope composition indicated mantle contributions of up to 40%, and the C-isotope composition of CO2 indicated that it predominantly (〉90%) originated from limestone decomposition. The groundwater composition was suggestive of mixing between meteoric and hydrothermally modified sea-water endmembers and water–rock interaction processes limited to simple rock dissolution driven by an increased endogenous CO2 content. All of the thermal manifestations and anomalous degassing areas, although of limited extent, were spatially correlated with the main active tectonic system of the area. The total CO2 output of the volcanic system has been preliminary estimated to be less than 0.05 kg s–1. Although this value is very low compared to those of other volcanic systems, anomalous CO2 degassing at Methana – which is currently restricted to limited areas and at present is the only volcanic risk of the peninsula – is a potential gas hazard that warrants further assessment in future studies.
    Description: Published
    Description: 818-828
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Methana ; south Aegean volcanic arc ; fluids geochemistry ; soil gases ; groundwaters ; 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::04.02. 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::04.08.08. Volcanic risk
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  • 42
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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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  • 43
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    Mantle-derived carbon in Hercynian granites. 1 Stable isotopes signatures 2 and C/He associations in the thermomineral waters, N-Portugal (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Na–HCO3–CO2-rich thermomineral waters issue in the N of Portugal, within the Galicia-Trás-os-Montes region, linked to a major NNE-trending fault, the so-called Penacova-Régua-Verin megalineament. Along this tectonic structure different occurrences of CO2-rich thermomineral waters are found: Chaves hot waters (67 °C) and also several cold (16.1 °C) CO2-rich waters. The δ2H and δ18O values of the thermomineral waters are similar to those of the local meteoric waters. The chemical composition of both hot and cold mineral waters suggests that water–rock reactions are mainly controlled by the amount of dissolved CO2 (g) rather than by the water temperature. Stable carbon isotope data indicate an external CO2 inorganic origin for the gas. δ13CCO2 values ranging between −7.2‰ and −5.1‰ are consistent with a two-component mixture between crustal and mantle-derived CO2. Such an assumption is supported by the 3He/4He ratios measured in the gas phase, are between 0.89 and 2.68 times the atmospheric ratio (Ra). These ratios which are higher than that those expected for a pure crustal origin (≈0.02 Ra), indicating that 10 to 30% of the He has originated from the upper mantle. Release of deep-seated fluids having a mantle-derived component in a region without recent volcanic activity indicates that extensive neo-tectonic structures originating during the Alpine Orogeny are still active (i.e., the Chaves Depression).
    Description: In press
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: open
    Keywords: CO2-rich thermomineral waters ; mantle volatiles ; isotopes ; Chaves geothermal 9 system ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 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
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  • 44
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    Dissolved helium isotope ratios in ground-waters: a new technique based on gas–water re-equilibration and its application to Stromboli volcanic system (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Here, a new technique for the determination of dissolved He isotope ratios in ground-waters is presented. This method is based on the extraction and subsequent equilibrium of dissolved gases in an added ‘‘host’’ gas phase. Ultra pure N2 is placed in glass flasks (250 cc), containing water samples, that were hermetically sealed after their collection. After shaking in an ultrasonic bath for 10 min, an aliquot of the separated gas phase was removed from the flask for MS analysis. 3He/4He ratios are measured by using a modified double collector mass spectrometer (VG 5400-TFT). Helium and Ne concentrations are calculated by comparing the partial pressures of masses 4 and 20 of the samples with those of the air-standard measured by a quadrupole mass spectrometer (QMS;VG Quartz). Using He and Ne equilibrium partitioning coefficients, it is possible to calculate the amount of gas originally dissolved in the water. The technique was tested on both air-saturated waters (ASW) and thermal waters from Stromboli (Aeolian Islands, South Italy), the results of which confirmed good reproducibility (ffi5%) and accuracy (ffi3%) of the data. The method was then applied to three thermal water samples collected from the same volcanic area and the results compared with those of a fumarolic and a soil gas. The isotope ratios for dissolved He gave values of 4.06–4.23 Ra, which are significantly higher than those previously reported in the literature (3.0, 3.5 and 2.9 Ra) and that measured at the fumarole (3.09 Ra), suggesting a newer and higher isotopic signature for the volcanic system. The proposed method appears to be a useful tool in the determination of 3He/4He ratios in ground-water systems, especially when free gases are not available or are dangerous to collect.
    Description: Published
    Description: 665–673
    Description: partially_open
    Keywords: dissolved helium isotopes ; gas water interaction ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 45
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    Isotopic, chemical and dissolved gas constraints on spring water from Popocatepetl volcano (Mexico): evidence of gas–water interaction between magmatic component and shallow fluids (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Geochemical research was carried out on cold and hot springs at Popocatepetl (Popo) volcano (Mexico) in 1999 to identify a possible relationship with magmatic activity. The chemical and isotopic composition of the fluids is compatible with strong gas–water interaction between deep and shallow fluids. In fact, the isotopic composition of He and dissolved carbon species is consistent with a magmatic origin. The presence of a geothermal system having a temperature of 80–1008 C was estimated on the basis of liquid geothermometers. A large amount of dissolved CO2 in the springs was also detected and associated with high CO2 degassing.
    Description: Published
    Description: 91– 108
    Description: partially_open
    Keywords: Popocatepetl volcano ; helium isotope composition ; carbon isotope composition ; dissolved gases ; gas–water interaction ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 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
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  • 46
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    Eddy covariance measurements of geothermal heat flux at Solfatara Volcano, Naples, Italy (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The first measurements of volcanic/hydrothermal water vapor and heat flux using eddy covariance (EC) were made at Solfatara crater, Italy, June 8–25, 2001. Deployment at six different locations within the crater allowed areas of focused gas venting to be variably included in the measured flux. Turbulent (EC) fluxes of water vapor varied between 680 and 11200g H2O m−2 d−1. Heat fluxes varied diurnally with the solar input, and the volcanic component of sensible heat ranged from ∼25 to 238W m−2. The highest measurements of both sensible and latent heat flux were made downwind of hot soil regions and degassing pools and during mid-day. The ratio of average volcanic heat (both latent and sensible) to CO2 flux resulted in an equivalent H2O/CO2 flux ratio of 2.2 by weight, which reflects the deep source H2O/CO2 gas ratio. The amount latent heat flux/evaporation was determined to be consistent both with what would be expected from the magnitude of CO2 fluxes and the fumarolic H2O/CO2 ratio, as well as with observed surface temperatures and wind speeds given a moist soil. This suggests that the water vapor that condenses in the shallow subsurface is remobilized at the soil–atmosphere interface through variable evaporation dependent on the deep heat flux and surface temperature. The results suggest that EC provides a quick and easy method to monitor average H2O/CO2 ratios continuously in volcanic regions, providing another important tool for volcanic hazards monitoring.
    Description: Published
    Description: 72–82
    Description: reserved
    Keywords: eddy covariance ; volcanic ; heat flux ; water vapor ; hydrothermal ; degassing ; flux ; emissions ; 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
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  • 47
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    A critical revision of the seismicity of Northern Apulia (Adriatic microplate - Southern Italy) and implications for the identification of seismogenic structures (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Northern Apulia is an emerged portion of the Adriatic microplate, representing the foreland–foredeep area of a stretch of the Apennine chain in southern Italy. The interaction between the relatively rigid microplate and the contiguous more deformable domains is responsible for the intense seismicity affecting the chain area. However strong, sometimes even disastrous, earthquakes have also hit northern Apulia on several occasions. The identification of the causative faults of such events is still unclear and different hypotheses have been reported in literature. In order to provide guidelines and constraints in the search for these structures, a comprehensive re-examination and reprocessing of all the available seismic data has been carried out taking into consideration 1) the characteristics of historical events, 2) the accurate relocation of events instrumentally recorded in the last 20 years, 3) the determination of focal mechanisms and of the regional stress tensor. The results obtained bring to light a distinction between the foreland and foredeep areas. In the first region there is evidence of a regional stress combining NWcompression and NE extension, thus structures responsible for major earthquakes should be searched for among strike–slip faults, possibly with a slight transpressive character. These structures could be either approximately N–S oriented sinistral or E–Wdextral faults. In the foredeep region there is a transition toward transtensive mechanisms,with strikes similar to those of the previous zone, or maybe also towardsNWoriented normal faults,more similar to those prevailing in the southern Apennine chain in relation to a dominant NE extension; this appears to be the effect of a reduction of the NW compression, probably due to a decrease in efficiency of stress transmission along the more tectonised border of the Adriatic microplate.
    Description: Published
    Description: 9 - 35
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Northern Apulia ; Historical earthquakes ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 48
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    Geomorphological, paleontological and 87Sr/86Sr isotope analyses of early Pleistocene paleoshorelines to define the uplift of Central Apennines (Italy) (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The eastern border of the Middle Valley of the Tiber River is characterized by several Plio-Pleistocene paleoshorelines, which extend for about 100 km along the western margin of the Central Apennines (Italy). We studied these paleoshorelines by the means of geological and paleontological analyses and new 87Sr/86Sr isotope analyses. The youngest and uppermost paleoshorelines have been detected and mapped through detailed geologic and stratigraphic surveys, which led to the recognition of nearshore deposits, cliff breccias, alignments of Lithophaga borings, fossil abrasion notches and wave-cut platforms. The altitude of these paleoshorelines decreases almost regularly in the NNW–SSE direction from 480 to 220 m a.s.l. Measurements of the 87Sr/86Sr isotope ratio have been conducted on corals and mollusks collected from sediments outcropping close to the paleoshorelines. The isotopic dating results indicate numerical values that range between 0.70907 and 0.70910 all over the 100-km outcrop. These results, together with biostratigraphic data, constrain the age of the youngest paleoshorelines to 1.65–1.50 Ma. These paleoshorelines are thus considered almost isochronous, giving an estimated uplift rate of 0.34–0.17±0.03 mm/a moving from NNW to SSE. Shape, length and continuity of the 100-km-long observed movements indicate that the studied paleoshorelines are an important marker of the Quaternary uplift of the Central Apennines.
    Description: Published
    Description: 487-501
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Early Pleistocene ; shoreline ; uplift ; Apennines ; Sr isotope ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous
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  • 49
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    Statistical Occurrence Analysis and Spatio-temporal Distribution of Earthquakes in the Apennines (Italy) (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We present two examples of statistical analysis of seismicity conducted by integrating geological, geophysical and seismological data with the aim to characterize the active stress field and to define the spatio-temporal distribution of large earthquakes. Moreover, our data will help to improve the knowledge of the “seismogenic behavior” of the areas and to provide useful information for seismic hazard evaluation. The earthquakes are described by two non-parametric statistical procedures integrating also tectonic-physical parameters to study the spatio-temporal variability. The results show that the areas are characterized by: 1) a stress regime with mainly extensional kinematics; 2) tectonic structures mainly oriented with the active stress field (Shmin=N44°18° in the southern Apennines and Shmin=N50°17° in the central Apennines); 3) cluster distribution of seismicity and 4) a high probability of earthquake occurrence (M〉5.5) in the next 10 years.
    Description: Published
    Description: 13-31
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: statistical analysis ; seismicity ; seismotectonics ; Apennines ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability
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  • 50
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    Dynamics of the transition zone under Europe inferred from wavelet cross-spectra of seismic tomography (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Tomographical results are commonly presented in the form of color images and not much statistical quantification has been carried out on the derived models. Correlation between different depths can shed important light concerning the dynamics. We have generalized the application of multidimensional wavelets to investigate the products of two field variables, such as the cross-spectrum, which is of paramount importance for quantifying the correlation between two depth levels of seismic tomography with a multiple-scale character. For two multidimensional fields A and B, we calculate the correlation C by projecting this as an Hermitian inner product in physical space with a two-dimensional (2D), fourth derivative of the Gaussian wavelet as the weighting function. The correlation function C becomes now a multi-scaled function, a map cast in terms of both the scale and location of the wavelet transform. Having calculated C, we can delineate the locations and length-scales of the prominent features in the landscape of the correlation function. This wavelet formulation is very general and can be extended to other types of statistical analysis, for example in a Kalman filter system. We have used a high-resolution (finer than 1◦) seismic tomographical model for analyzing the extent of mantle layering under Europe by focussing on the different length-scales in the correlation function involving the 3D seismic anomalies lying between 400 and 600 km depth. Between the depths of 500 and 600 km under Europe, the wavelet correlation analysis shows that an ellipse-shaped object exists with an area of 2000 km × 4000 km having a strong correlation for length-scales of around 400 km, and weaker correlation for shorter length scales of around 150 km. On the other hand, between depths of 400 and 600 km, the correlation deteriorates on the long length scales and becomes even worse at the short length scales. From the wavelet correlation spectra, we can extract an horizontal characteristic length scale of around 100 km, which may be related to the boundary interaction between the slab and the ambient mantle. The correlation results suggest that the thickness of the recumbent fast (cold) material in the transition zone is between 100 and 150 km. This large elliptical pattern of presumably cold material would act to inhibit the vigor of mantle convection locally beneath Europe today.
    Description: Published
    Description: 125–139
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: wavelets ; correlation ; tomography ; transition zone ; Mediterranean ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 51
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    Orogens and slabs vs. their direction of subduction (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Subduction zones appear primarily controlled by the polarity of their direction, i.e., W-directed or E- to NNE-directed, probably due to the westward drift of the lithosphere relative to the asthenosphere. The decollement planes behave differently in the two end-members. In the W-directed subduction zone, the decollement of the plate to the east is warped and subducted, whereas in the E- to NNE-directed, it is ramping upward at the surface. There are W-directed subduction zones that work also in absence of active convergence like the Carpathians or the Apennines. W-directed subduction zones have shorter life 30–40 Ma.than E- or NE-directed subduction zones even longer than 100 Ma.. The different decollements in the two end-members of subduction should control different PTt paths and, therefore, generate variable metamorphic assemblages in the associated accretionary wedges and orogens. These asymmetries also determine different topographic and structural evolutions that are marked by low topography and a fast ‘eastward’ migrating structural wave along W-directed subduction zones, whereas the topography and the structure are rapidly growing upward and expanding laterally along the opposite subduction zones. The magmatic pair calc-alkaline and alkaline–tholeiitic volcanic products of the island arc and the back-arc basin characterise the W-directed subduction zones. Magmatic rocks associated with E- or NE-directed subduction zones have higher abundances of incompatible elements, and mainly consist of calc-alkaline– shoshonitic suites, with large volumes of batholithic intrusions and porphyry copper ore deposits. The subduction zones surrounding the Adriatic plate in the central Mediterranean confirm the differences among subduction zones as primarily controlled by the geographic polarity of the main direction of the slab. The western margin of the Adriatic plate contemporaneously overridden and underthrust Europe toward the ‘west’ to generate, respectively, the Alps and the Apennines, while the eastern margin subducted under the Dinarides–Hellenides. These belts confirm the characters of the end-members of subduction zones as a function of their geographic polarity similarly to the Pacific subduction zones.
    Description: Published
    Description: 167–208
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: tectonics ; subduction zones ; orogens ; Mediterranean geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 52
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    The southern Tyrrhenian subduction zone: Deep geometry, magmatism and Plio-Pleistocene evolution (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We report on a high-resolution Vp, Vp/Vs and Qp model of the southern Tyrrhenian subduction zone, obtained by the inversion of P- and S wave arrival times and t* values from intraslab seismicity. The arcuate shape of the southern Apennines–Calabrian arc-Sicilian Maghrebides is perfectly mirrored by two rather continuous low and high Vp bands lying beneath the belt system at ca. 25 and 100 km, respectively. Between 100 and 300 km, two independent high Vp slabs lie beneath the Neapolitan region and the southern Tyrrhenian Sea, separated by unperturbed mantle. We suggest that the ca. 150 km-wide slab window beneath the southern Apennines opened after a tear occurring within a composite subduction system, formed by the Apulian continental lithosphere and the Ionian oceanic slab. The abrupt slab rupture induced ultrafast southeastward retreat of the Ionian slab, and the 19 cm/yr spreading of the back-arc oceanic Marsili basin between ca. 2.1 and 1.6 Ma ago. The 25 km low Vp zone beneath the arc denotes continental upper crustal rocks below the chain. Its striking continuity requires a unique orogenic wedge at 25 km depth below the southern Apennines, the Calabrian arc, and the Sicilian Maghrebides. The alternative explanation would imply the ubiquitous occurrence of autochthonous lower plate rocks at 25 km depth, i.e. a puzzling autochthonous continental Calabria. The Ionian slab beneath Calabria shows high Vp, high Qp and low Vp/Vs anomalies, typical of old oceanic lithosphere. Intermediate depth seismicity is concentrated within its thin oceanic crust, suggesting the occurrence of vigorous metamorphism. The slab dehydration promotes the melting of the overlying mantle, as testified by high Vp/Vs and low Qp anomalies between the slab and the Aeolian magmatic arc.
    Description: Published
    Description: 408-423
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: seismic tomography ; recent evolution of the Ionian slab ; deep earthquakes slab dehydration and magmatism ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs
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  • 53
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    Vertical-axis rotation of a foreland fold and implications for orogenic curvature: an example from the Southern Pyrenees, Spain (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In curved orogenic systems where thrusting and vertical-axis rotations have been documented, it is possible to determine whether the curvature is secondary or progressive based on the timing between the two motions. The South-Central Unit of the Southern Pyrenees provides an opportunity to investigate relationships between thrusting, folding, and vertical-axis rotation because of unusual preservation of Tertiary synorogenic sedimentary strata. Paleomagnetic samples were collected from 51 sites in the upper Eocene-lower Oligocene continental synorogenic strata of the Oliana anticline, a foreland fold along the eastern margin of the South-Central Unit. Site-mean characteristic remanent magnetization directions were determined from 17 sites through thermal demagnetization and principal component analysis. In addition, 72 samples were collected from 39 stratigraphic levels spanning the Upper Eocene marine marls and treated with thermal and alternating field demagnetization techniques. Of these, 53 samples yielded demagnetization trajectories that further constrained the rotation. Comparison of the observed mean paleomagnetic direction from the Oliana anticline with the expected direction indicates a counterclockwise rotation (R ± ΔR) of 20.3° ± 10.9°. Based on the stratigraphic horizons recording the rotation, the age of the rotation is younger than ~34 Ma (after deposition of Unit 3). Data covering the Upper Eocene-Lower Oligocene time interval indicate a similar magnitude of rotation, suggesting that late stage emplacement of thrust sheets hinterlandward of the Oliana anticline controlled the rotation, with rotation accommodated along regionally extensive evaporites. The well-constrained timing relationships between thrusting and rotation and the regional and local transport directions, suggest that the South-Central Unit is a progressive curve that formed through distributed shortening.
    Description: Published
    Description: 435-449
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: reserved
    Keywords: Pyrenees ; Oliana anticline ; synorogenic strata ; paleomagnetism ; salients ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 54
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    Paleo-environmental and volcano-tectonic evolution of the southeastern £ank of Mt. Etna during the last 225 ka inferred from the volcanic succession of the ‘Timpe’, Acireale, Sicily (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The tectonic escarpments locally known as ‘Timpe’ cut a large sector of the eastern flank of Etna, and allow an ancient volcanic succession dating back to 225 ka to be exposed. Geological and volcanological investigations carried out on this succession have allowed us to recognize relevant angular unconformities and volcanic features which are the remnants of eruptive fissures, as well as important changes in the nature, composition and magmatic affinity of the exposed volcanics. In particular, the recognition in the lower part of the succession of important and unequivocal evidence of ancient eruptive fissures led us to propose a local origin for these volcanics and to revise previous interpretations which attributed their westward-dipping to the progressive tectonic tilting of strata. These elements led us to reinterpret the main features of the volcanic activity occurring since 250 ka BP and their relationship with tectonic structures active in the eastern flank of Etna. We propose a complex paleo-environmental and volcanotectonic evolution of the southeastern flank of Mt. Etna, in which the Timpe fault system played the role of the crustal structure that allowed the rise and eruption of magmas in the above considered time span.
    Description: Published
    Description: 289-306
    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: JCR Journal
    Description: reserved
    Keywords: Mount Etna ; tectonics ; fisssure eruptions ; columnar basalt ; fault escarpment ; xenoliths ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. 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::04.08.07. Instruments and techniques ; 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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  • 55
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    Carbon isotopic composition of soil CO2 efflux, a powerful method to discriminate different sources feeding soil CO2 degassing in volcanic-hydrothermal areas (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: A new method combining measurements of soil CO2 flux and determinations of the carbon isotopic composition of soil CO2 efflux was developed in order to qualitatively and quantitatively characterise the CO2 source feeding the soil CO2 diffuse degassing. The method was tested in March 2007 at the Solfatara of Pozzuoli volcano degassing area (Naples, Italy) where more than 300 measurements of soil CO2 flux and determinations of the carbon isotopic composition of soil CO2 efflux were performed, surveying Solfatara crater and its surroundings. The wide range of CO2 flux and CO2 isotopic composition values (from 8.4 g m−2 d−1 to 28,834 g m−2 d−1, and from 0.73‰ to −33.54‰, respectively), together with their statistical distributions suggests the occurrence of multiple CO2 sources feeding soil degassing. The combined interpretation of flux and isotopic data allows us to identify and characterise two distinct gas sources: a hydrothermal and a biogenic source. The soil CO2 from the hydrothermal source is characterised by a mean δ13CCO2 of −2.3‰±0.9‰, hence close to the isotopic composition of the fumarolic CO2 (δ13CCO2=−1.48‰± 0.22‰) and by a mean CO2 flux of 2875 g m−2 d−1. The CO2 from the biogenic source is characterised by a mean δ13CCO2 of −19.4‰±2.1‰, and by a mean CO2 flux of 26 g m−2 d−1, which are both in the range of the typical values for biologic CO2 soil degassing. This reliable characterisation of the biogenic CO2 flux would not have been possible by solely applying a statistical analysis of the CO2 flux values, which is commonly applied in volcanological studies for the partitioning between background fluxes and anomalous CO2 fluxes. A map of the Solfatara diffuse degassing structure was derived from the estimated threshold for the biogenic CO2 flux, highlighting that soil degassing of hydrothermal CO2 mixed in different proportion with biogenic CO2 occurs over a large area (~0.8 km2), which extends over the inner part of the Solfatara crater as well as the eastern periphery, corresponding with a NW–SE fault system. The presented method and data analysis are important means of surveillance of the volcanic activity.
    Description: Published
    Description: 372–379
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: CO2 soil degassing ; CO2 flux ; carbon dioxide ; carbon isotopes ; 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
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  • 56
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    Geochemical and biochemical evidence of lake overturn and fish kill at Lake Averno, Italy (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Lake Averno is situated in the homonymous crater in the northwestern sector of the Campi Flegrei active volcanic system in Campania region, Italy. In February 2005 a fish kill event was observed in the lake, prompting a geochemical survey to ascertain the possible cause. In February 2005 a geochemical survey revealed that the lake water was unstratified chemically and isotopically, presumably, as a result of lake overturn. This fish kill phenomenon was recorded at least two other times in the past. In contrast to the February 2005 results, data collected in October 2005, shows the Lake Averno to be stratified, with an oxic epilimnion (surface to 6 m) and an anoxic hypolimnion (6 m to lake bottom at about 33 m). Chemical and isotopic compositions of Lake Averno waters suggest an origin by mixing of shallow waters with a Na–Cl hydrothermal component coupled with an active evaporation process. The isotopic composition of Dissolved Inorganic Carbon, as well as the composition of the non-reactive dissolved gas species again supports the occurrence of this mixing process. Decreasing levels of SO4 and increasing levels of H2S and CH4 contents in lake water with depth, strongly suggests anaerobic bacterial processes are occurring through decomposition of organic matter under anoxic conditions in the sediment and in the water column. Sulfate reduction and methanogenesis processes coexist and play a pivotal role in the anaerobic environment of the Lake Averno. The sulfate reducing bacterial activity has been estimated in the range of 14–22 μmol m−2 day−1. Total gas pressure of dissolved gases ranges between 800 and 1400 mbar, well below the hydrostatic pressure throughout the water column, excluding the possibility, at least at the survey time, of a limnic eruption. Vertical changes in the density of lake waters indicate that overturn may be triggered by cooling of epilimnetic waters below 7 °C. This is a possible phenomenon in winter periods if atmospheric temperatures remain frosty for enough time, as occurred in February 2005. The bulk of these results strongly support the hypothesis that fish kill was caused by a series of events that began with the cooling of the epilimnetic waters with breaking of the thermal stratification, followed by lake overturn and the rise of toxic levels of H2S from the reduced waters near the lake bottom.
    Description: Published
    Description: 305–316
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Degassamento naturale
    Description: JCR Journal
    Description: reserved
    Keywords: lake Averno ; dissolved gases ; stable isotopes ; stable isotopes ; 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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  • 57
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    From mantle to crust: Stretching the Mediterranean (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The origin of forces driving the deformation of the continental crust near subduction zones and especially in backarc regions is debated. Thiswork is based on a compilation of SKS fast splitting directions that give an image of flowlines in themantle around theMediterranean subduction zones and a comparisonwith stretching and shear directions in metamorphic core complexes that show the pattern of deformation at the scale of the middle and lower crusts.We find that : (1) the two sets of directions are parallel in the three main backarc regions, namely the Alboran Sea, the Tyrrhenian Sea and the Aegean Sea showing that the lithosphere deformswith the samedirection of stretching in the crust and themantle, suggesting that (2) crustal deformation ismainly driven frombelowby slab retreat, and (3) the lithospheric fabric is reset within a few millions of years in backarc environments.
    Description: Published
    Description: 198–209
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: subduction ; seismic anisotropy ; backarc extension ; slab retreat ; stretching lineation ; metamorphic core complexes ; Mediterranean ; Aegean ; Tyrrhenian ; Alboran ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 58
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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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  • 59
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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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  • 60
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    Can Earth's rotation and tidal despinning drive plate tectonics? (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We re-evaluate the possibility that Earth's rotation contributes to plate tectonics on the basis of the following observations: 1) plates move along a westerly polarized flow that forms an angle relative to the equator close to the revolution plane of the Moon; 2) plate boundaries are asymmetric, being their geographic polarity the first order controlling parameter; unlike recent analysis, the slab dip is confirmed to be steeper along W-directed subduction zones; 3) the global seismicity depends on latitude and correlates with the decadal oscillations of the excess length of day (LOD); 4) the Earth's deceleration supplies energy to plate tectonics comparable to the computed budget dissipated by the deformation processes; 5) the Gutenberg–Richter law supports that the whole lithosphere is a self-organized system in critical state, i.e., a force is acting contemporaneously on all the plates and distributes the energy over the whole lithospheric shell, a condition that can be satisfied by a force acting at the astronomical scale. Assuming an ultra-low viscosity layer in the upper asthenosphere, the horizontal component of the tidal oscillation and torque would be able to slowly shift the lithosphere relative to the mantle.
    Description: Hungarian Scientific Research Fund OTKA in the framework of project K 60394
    Description: Published
    Description: 60-73
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: reserved
    Keywords: Plate tectonics ; Earth's rotation ; Tidal despinning ; Earth's energy budget ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 61
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    CO2 degassing at La Solfatara volcano (Phlegrean Fields): Processes affecting d13C and d18O of soil CO2 (2010)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The soil CO2 degassing is affected by processes of isotope exchange and fractionation during transport across the soil, which can deeply modify the pristine isotope composition. This has been observed in the Solfatara volcano, upon a field survey of 110 points, where the CO2 flux was measured, together with temperature, CO2 concentration and oxygen and carbon isotopes within the soil. Furthermore, in some selected sites, the measurements were made at different depths, in order to analyze vertical gradients. Oxygen isotope composition appears controlled by exchange with soil water (either meteoric or fumarolic condensate), due to the fast kinetic of the isotopic equilibrium between CO2 and water. Carbon isotope composition is reliably controlled by transport-driven fractionation, due to the differences in diffusion coefficients between 13C16O2 and 12C16O2. We model the processes affecting CO2 transport across the soil in La Solfatara volcano by means of the Dusty Gas Model applied to a multicomponent system, to evaluate the reciprocal effect on diffusion of involved gases, i.e. 12C16O2, 13C16O2, N2 and O2 in our case. Both numerical and simplified analytical solutions of the equations based on the Dusty Gas Model are given. The modeling results fit well with the experimental data and put in evidence an isotope fractionation of carbon up to about þ4:4& with respect to the source value in the soil gas. This fractionation is independent from the entity of the CO2 flux, and occurs as long as a concentration gradient exists within the soil. On these grounds, the Dusty Gas Model can be applied to whichever diffusing gas mixture to evaluate the extent of chemical and/or isotopic fractionation that can affect ascending gases upon diffusion in any geothermal, volcanic or tectonic area.
    Description: Published
    Description: 3521-3528
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: isotope exchange ; degassing ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 62
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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
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  • 63
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    A pilot GIS database of active faults of Mt. Etna (Sicily): A tool for integrated hazard evaluation (2012)
    Elsevier Science Limited
    In:  Supplementary data associated with this article can be found in the online version, at http://dx.doi.org/10.1016/j.jvolgeores.2012.08. 013.
    Details
    Publication Date: 2017-04-04
    Description: A pilot GIS-based system has been implemented for the assessment and analysis of hazard related to active faults affecting the eastern and southern flanks of Mt. Etna. The system structure was developed in ArcGis® environment and consists of different thematic datasets that include spatially-referenced arc-features and associated database. Arc-type features, georeferenced into WGS84 Ellipsoid UTM zone 33 Projection, represent the five main fault systems that develop in the analysed region. The backbone of the GIS-based system is constituted by the large amount of information which was collected from the literature and then stored and properly geocoded in a digital database. This consists of thirty five alpha-numeric fields which include all fault parameters available from literature such us location, kinematics, landform, slip rate, etc. Although the system has been implemented according to the most common procedures used by GIS developer, the architecture and content of the database represent a pilot backbone for digital storing of fault parameters, providing a powerful tool in modelling hazard related to the active tectonics of Mt. Etna. The database collects, organises and shares all scientific currently available information about the active faults of the volcano. Furthermore, thanks to the strong effort spent on defining the fields of the database, the structure proposed in this paper is open to the collection of further data coming from future improvements in the knowledge of the fault systems. By layering additional user-specific geographic information and managing the proposed database (topological querying) a great diversity of hazard and vulnerability maps can be produced by the user. This is a proposal of a backbone for a comprehensive geographical database of fault systems, universally applicable to other sites.
    Description: Published
    Description: 170-186
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 5.5. TTC - Sistema Informativo Territoriale
    Description: JCR Journal
    Description: reserved
    Keywords: GIS-based system ; Hazard assessment ; Volcano-tectonics ; Flank dynamics ; Georeferenced arc-features ; Active fault database ; 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::04.04.06. Rheology, friction, and structure of fault zones ; 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::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 64
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    An alternative model for the recent evolution of the Northern–Central Apennines (Italy) (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: The aim of this paper is to propose an alternative model for the Pliocene-Quaternary to present evolution of the Northern–Central Apennines by combining geometrical requirements (Riedel shear system) with existing structural and geological geometries (fault systems and their tectonic associations). We define three sectors characterized by different geological, seismological, geodetic and geothermal signatures: the North-Western Sector (NWS), the Western Central Sector (WCS) and the Eastern Central Sector (ECS). According to GPS data derived from literature the three blocks move independently. In particular, the NWS is bound between the ECS/WCS and the Alps; this constraint leads to a stress accumulation responsible for a fragmentation into further several blocks, which move either to the NE or SW. The WCS is relatively stable; the ECS moves towards NE and is characterized by the presence of numerous releasing and restraining bends, which can be related to the action of a main NNW–SSE left-lateral shear zone. Accordingly, the recent and active tectonic setting of the Northern–Central Apennines is rather related to the dynamics of the introduced blocks, caused by the push of the African plate against Europe, than to subduction processes.
    Description: Published
    Description: 55-63
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: Northern-Central Apennines ; Riedel shear system ; Strike slip ; Restraining and releasing bends ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 65
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    Detection of fresh and thermal waters over an island with extinct volcanism: the island of Salina (Aeolian arc, Italy) (2012)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: A geochemical prospection of the fluids circulating over a volcanic island highlighted the existence of reservoirs of both fresh and thermal water although only a few natural manifestation, mainly occurring in submarine environment, provide clues of their existence. Coupling the information provided by the diffuse gas bubbling and the low-salinity waters discharged from the sea floor off the Island with those from the low-salinity and thermal waters collected from in-land wells drilled in recent times we found that a large amount of fresh and thermal waters are continuously discharged at the sea level. The thermal waters, collected at a temperature of 32-36°C, show a typical marine recharge with equilibrium temperatures estimated to be in the range of 120-160°C. As matter of fact, the small island holds relatively large reservoirs of both fresh and thermal waters. The geochemical features of the circulating fluids are driven by water-rock and gas-water interaction processes, while the heat supplied to the geothermal reservoir comes from volcanic rocks that are still cooling down after the end of the last volcanic activity supposed to be not older than 13ky.
    Description: Published
    Description: 39-49
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: N/A or not JCR
    Description: restricted
    Keywords: geochemistry ; thermal fluids ; volcanism ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
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  • 66
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    Seismic moment tensors and regional stress in the area of the December 2013–January 2014, Matese earthquake sequence (Italy) (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: The main goal of this study is to provide moment tensor solutions for small and moderate earthquakes of the Matese seismic sequence in southern Italy for the period of December 2013–January 2014. We estimate the focal mechanisms of 31 earthquakes with local magnitudes related to the Matese earthquake seismic sequence (December 2013–January 2014) in Southern-Central Italy which are recorded by the broadband stations of the Italian National Seismic Network and the Mediterranean Very Broadband Seismographic Network (MedNet) run by the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The solutions show that normal faulting is the prevailing style of seismic deformation in agreement with the local faults mapped outin the area. Comparisons with already published solutions and with seismological and geological information available allowed us to properly interpret the moment tensor solutions in the frame of the seismic sequence evolution and also to furnish additional information about less energetic seismic phases. Focal data were inverted to obtain the seismogenic stress in the study area. The results are compatible with the major tectonic domain of the area.
    Description: Published
    Description: 118-124
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Moment tensors ; Southern Italy ; Apennines ; Stress inversion ; Seismicity and tectonics ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 67
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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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  • 68
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    Seismotectonic features from accurate hypocentre locations in southern central Andes (western Argentina) (2011)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: A local seismic network, over a five-year period, recorded about 450 earthquakes in western Argentina. In this region, the geodynamics is controlled by the subduction of the Nazca plate beneath the South American lithosphere, which is characterised here by a sub-horizontal path before reassuming its downward descent. As accurate earthquake locations are of primary importance when studying the seismicity of a given area, events recorded by the local seismic network enable in-depth investigations into seismo-tectonic patterns, allowing to improve the earthquake source characterization and knowledge on the ongoing seismo-tectonics of the region. To this end, we performed a simultaneous 1-D inversion of both the velocity structure and the hypocentre location. The minimum 1-D model obtained is complemented by station corrections which lead to a first insight into the deeper 3-D structure. In addition, stability tests were performed to verify the robustness of our earthquake location results. They reveal a fairly stable hypocentre determination, demonstrating that the locations obtained by the inversion process are not systematically biased. The results show that Sierra Pie de Palo is characterised by a crustal seismogenic structure, dipping west and extending from its eastern boundary to about 30 km of depth. The study also provided new constraints on the geometry of the subducted slab. We noted a great concentration of shallower seismicity compared to that of the surrounding areas of the Wadati-Benioff zone, at the expected position of the Juan Fernandez Ridge (JFR). Our hypocentres indicate that JFR certainly influences the subduction style along its strike, leading to the formation of a bend in the slab geometry.
    Description: Published
    Description: 44-54
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Minimum 1-D velocity model ; high precision earthquake location ; seismogenic structure ; flat-slab subduction ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 69
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    Strain and stress fields in the Southern Apennines (Italy) constrained by geodetic, seismological and borehole data (2012)
    Blackwell Publishing Ltd
    Details
    Publication Date: 2017-04-04
    Description: We present an improved evaluation of the current strain and stress fields in Southern Apennines (Italy) obtained through a careful analysis of geodetic, seismological and borehole data. In particular, our analysis provides an updated comparison between the accrued strain recorded by geodetic data, and the strain released by seismic activity in a region hit by destructive historical earthquakes. To this end, we have used 9 years of GPS observations (2001-2010) from a dense network of permanent stations, a dataset of 73 well constrained stress indicators (borehole breakouts and focal mechanisms of moderate to large earthquakes), and published estimations of the geological strain accommodated by active faults in the region. Although geodetic data are generally consistent with seismic and geologic information, previously unknown features of the current deformation in southern Italy emerge from this analysis. The newly obtained GPS velocity field supports the well-established notion of a dominant NE-SW-oriented extension concentrated in a ~50 km wide belt along the topographic relief of the Apennines, as outlined by the distribution of seismogenic normal faults. Geodetic deformation is, however, non uniform along the belt, with two patches of higher strain-rate and shear stress accumulation in the north (Matese Mountains) and in the south (Irpinia area). Low geodetic strain-rates are found in the Bradano basin and Apulia plateau to the east. Along the Ionian Sea margin of southern Italy, in southern Apulia and eastern Basilicata and Calabria, geodetic velocities indicate NW-SE extension which is consistent with active shallow-crustal gravitational motion documented by geological studies. In the west, along the Tyrrhenian margin of the Campania region, the tectonic geodetic field is disturbed by volcanic processes. Comparison between the magnitude of the geodetic and the seismic strain-rates (computed using a long historical seismicity catalogue) allow detecting areas of high correlation, particularly along the axis of the mountain chain, indicating that most of the geodetic strain is released by earthquakes. This relation does not hold for the instrumental seismic catalogue, as a consequence of the limited time span covered by instrumental data. In other areas (e.g. Murge plateau in central Apulia), where seismicity is very low or absent, the yet appreciable geodetic deformation might be accommodated in aseismic mode. Overall, the excellent match between the stress and the strain-rate directions in much of the Apennines indicates that both earthquakes and ground deformation patterns are driven by the same crustal forces.
    Description: Published
    Description: 1270-1282
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Satellite geodesy ; Plate motions ; Neotectonics ; Europe ; Apennines ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
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  • 70
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    Can local earthquake tomography settle the matter about subduction in the Northern and Central Apennines? Response from a new high resolution P velocity and Vp/Vs ratio 3-D model (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: According to the most common interpretation, the Apennines developed in Neogene and Quaternary times in the hanging wall of a west directed subduction zone. Seismic tomography is the most powerful tool to investigate large volume of Earth at depth, and it has been extensively applied to shed light on the geometry and shape of the subduction under the Italian peninsula. The various experiments were able to display the slab under the Southern Apennines, but even the most recent tomographic images were non-uniquely interpretable and left open questions about the characteristics of the subduction in the Northern-Central sector of the chain. We here present the results of an improved inversion experiment focused on the Northern and Central Apennines. The results do not show any pronounced subduction slab and the most evident anomaly is a low velocity body extending down to 100 km depth, located in a relatively small area under the western Tuscany. On the basis of accurate synthetic tests, we assess that, if established, a subduction like geometry should be visible in our tomographic images. We then conclude that no subduction is imaged in the Northern and Central Apennines. We thus interpret this anomaly as an asthenospheric flow. However, we cannot exclude that our result is due to intrinsic limitations of the methodology. In fact in response to the original question about the capability of local earthquake tomography to settle the matter about subduction, we underline that the absence of deep earthquakes to illuminate the model from below, the existence of seismic gaps in some sectors of the area under study even at shallow depth and the non uniqueness of interpretation of the tomographic images make local tomography unable to give alone definitive information on the deep structure of the Northern and Central Apennines.
    Description: Published
    Description: 63-73
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: Seismic tomography ; Apennines ; Subduction ; Asthenospheric upwelling ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
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  • 71
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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
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  • 72
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    Foreland segmentation along an active convergent margin: New constraints in southeastern Sicily (Italy) from seismic and geodetic observations (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: We performed an in-depth analysis of the ongoing tectonics of a large sector of southern Sicily, including the Hyblean Foreland and the front of the Maghrebian Chain, as well as the Ionian Sea offshore, through the integration of seismic and GPS observations collected in the nearly two decades. In particular, a dataset consisting of more than 1100 small-to moderate-magnitude earthquakes (1.0 ≤ ML ≤ 4.6) has been used for local earthquake tomography in order to trace the characteristics of the faulting systems, and for focal mechanisms computation to resolve the current local stress field and to characterise the faulting regime of the investigated area. In addition, GPS measurements, carried out on both episodic and continuous stations, allowed us to infer the main features of the current crustal deformation pattern. Main results evidence that the Hyblean Plateau is subject to a general strike–slip faulting regime, with a maximum horizontal stress axis NW–SE to NNW–SSE oriented, in agreement with the Eurasia–Nubia direction of convergence. The Plateau is separated into two different tectonic crustal blocks by the left-lateral strike–slip Scicli–Ragusa Fault System. The western block moves in agreement with central Sicily while the eastern one accommodates part of the contraction arising from the main Eurasia–Nubia convergence. Furthermore, we provided evidences leading to consider the Hyblean–Maltese Escarpment Fault System as an active boundary characterised by a left-lateral strike–slip motion, separating the eastern block of the Plateau from the Ionian basin. All these evidences lend credit to a crustal segmentation of the southeastern Sicily.
    Description: Published
    Description: 137-149
    Description: 1T. Geodinamica e interno della Terra
    Description: JCR Journal
    Description: open
    Keywords: Southeastern Sicily ; Seismotectonics ; Tomography ; Focal mechanisms ; Crustal stress ; Geodetic strain rate ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 73
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    Quantitative models of hydrothermal fluid–mineral reaction: The Ischia case (2013)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: The intricate pathways of fluid–mineral reactions occurring underneath active hydrothermal systems are explored in this study by applying reaction path modelling to the Ischia case study. Ischia Island, in Southern Italy, hosts a well-developed and structurally complex hydrothermal system which, because of its heterogeneity in chemical and physical properties, is an ideal test sites for evaluating potentialities/limitations of quantitative geochemical models of hydrothermal reactions. We used the EQ3/6 software package, version 7.2b, to model reaction of infiltrating waters (mixtures of meteoric water and seawater in variable proportions) with Ischia’s reservoir rocks (the Mount Epomeo Green Tuff units; MEGT). The mineral assemblage and composition of such MEGT units were initially characterised by ad hoc designed optical microscopy and electron microprobe analysis, showing that phenocrysts (dominantly alkali–feldspars and plagioclase) are set in a pervasively altered (with abundant clay minerals and zeolites) groundmass. Reaction of infiltrating waters with MEGT minerals was simulated over a range of realistic (for Ischia) temperatures (95–260 C) and CO2 fugacities (10 0.2 to 100.5) bar. During the model runs, a set of secondary minerals (selected based on independent information from alteration minerals’ studies) was allowed to precipitate from model solutions, when saturation was achieved. The compositional evolution of model solutions obtained in the 95– 260 C runs were finally compared with compositions of Ischia’s thermal groundwaters, demonstrating an overall agreement. Our simulations, in particular, well reproduce the Mg-depleting maturation path of hydrothermal solutions, and have end-ofrun model solutions whose Na–K–Mg compositions well reflect attainment of full-equilibrium conditions at run temperature. High-temperature (180–260 C) model runs are those best matching the Na–K–Mg compositions of Ischia’s most chemically mature water samples, supporting quenching of deep-reservoir conditions for these surface manifestations; whilst Fe, SiO2 and, to a lesser extent, SO4 contents of natural samples are better reproduced in low-temperature (95 C) runs, suggesting that these species reflect conditions of water–rock interaction in the shallow hydrothermal environment. The ability of model runs to reproduce the compositional features of Ischia’s thermal manifestations, demonstrated here, adds supplementary confidence on reaction path modelling as a realistic and insightful representation of mineral–fluid hydrothermal reactions. Our results, in particular, demonstrate the significant impact of host rock minerals’ assemblage in governing the paths and trends of hydrothermal fluids’ maturation.
    Description: Published
    Description: 108-129
    Description: JCR Journal
    Description: restricted
    Keywords: Ischia ; Hydrothermal systems ; EQ3-6 ; Geochemical modelling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
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  • 74
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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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  • 75
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    Evidence of large scale deformation patterns from GPS data in the Italian subduction boundary (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We present the velocity field in Italy derived from over 300 continuous GPS stations operated in the 1998– 2009 time span. The GPS network maps the whole country with a mean inter-site distance of about 50 km and provides a valuable source of data to study the ongoing deformation processes in the central Mediterranean. The estimated horizontal and vertical velocity fields show major significant features and also less known second-order kinematic features. A general uplift characterizes the whole Apennines and Alpine belts that follow the topographic ridge, whereas the Po Plain shows a gradually increasing subsidence from west to east. The Apennines belt displays a distinctive extension (50–80 10−9 yr−1)while compressive tectonic regimes characterize northern Sicily, eastern Alps and the northeast front of the northern Apennines (25–50 10−9 yr−1). Second-order deformation patterns, on large scale wavelength (~100 km) have been detected on the accretionary prism of central and southern Apennines that are highly correlated with other geophysical data (Vp anomalies, seismic anisotropy, etc.) and related to deep rooted sections (70– 100 km), marked by different subduction regimes. Apparently at this scale-length the observed deformations are governed by the lithosphere as a whole. We interpret these deformations as a result of different subduction mechanisms, such as variations of the subduction rollback velocity affecting different segments of the subduction zone and/or to mantle flows in proximity of the slab edges. Further south, in central-southern Sicily, we detect a contraction of (−1.1±0.2) mm/yr that probably accommodates part of the Africa–Eurasia convergence on the outer thrust front of the Apennines–Maghrebides belt. This hypothesis agrees with an independent analysis of the seismicity associated to the Sicilian Basal Thrust, thought to be still active. The ITRF2005 estimates of the new GPS velocity field are available also in SINEX format as supplementary file S1.
    Description: Published
    Description: 230-241
    Description: 1.9. Rete GPS nazionale
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: GPS velocity field ; Apennines ; Alps ; Adria ; Plate kinematics ; Subduction zone ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous
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  • 76
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    An overview of experimental models to understand a complex volcanic instability: Application to Mount Etna, Italy (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: Volcanic edifices are often unable to support their own load, triggering the instability of their flanks. Many analogue models have been aimed, especially in the last decade, at understanding the processes leading to volcano flank instability; general behaviors were defined and the experimental results were compared to nature. However, available data at well-studied unstable volcanoes may allow a deeper understanding of the specific processes leading to instability, providing insights also at the local scale. Etna (Italy) constitutes a suitable example for such a possibility, because of its well-monitored flank instability, for which different triggering factors have been proposed in the last two decades. Among these factors, recent InSAR data highlight the role played by magmatic intrusions and a weak basement, under a differential unbuttressing at the volcano base. This study considers original and recently published experimental data to test these factors possibly responsible for flank instability, with the final aim to better understand and summarize the conditions leading to flank instability at Etna. In particular, we simulate the following processes: a) the longterm activity of a lithospheric boundary, as the Malta Escarpment, separating the Ionian oceanic lithosphere from the continental Sicilian lithosphere, below the most unstable east flank of the volcano; b) spreading due to a weak basement, with different boundary conditions; c) the pressurization of a magmatic reservoir, as that active during the 1994–2001 inflation period; d) dike emplacement, as observed during the major 2001 and 2002–2003 eruptions. The experimental results suggest that: 1) the long-term activity of a lithospheric tectonic boundary may create a topographic slope which provides a differential buttressing at the volcano base, a preparing factor to drive longer-term (〉105 years) instability on the east flank of the volcano; 2) volcano spreading (b104 years) has limited effect on flank instability at Etna; 3) magmatic intrusions (b101 years), both in the form of Mogi-like sources or dikes, provide the most important conditions to trigger flank instability on the shorter-term.
    Description: Thisworkwas partially funded by INGV and the Italian DPC (DPC-INGV project V4 “Flank”).
    Description: Published
    Description: 98-111
    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: JCR Journal
    Description: reserved
    Keywords: volcano instability ; analogue modeling ; Etna ; unbuttressing ; 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::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 77
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    Geochemical survey of Levante Bay, Vulcano Island (Italy), a natural laboratory for the study of ocean acidification (2013)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: Shallow submarine gas vents in Levante Bay, Vulcano Island (Italy), emit around 3.6t CO2 per day providing a natural laboratory for the study of biogeochemical processes related to seabed CO2 leaks and ocean acidification. The main physico-chemical parameters (T, pH and Eh) were measured at more than 70 stations with 40 seawater samples were collected for chemical analyses. The main gas vent area had high concentrations of dissolved hydrothermal gases, low pH and negative redox values all of which returned to normal seawater values at distances of about 400 m from the main vents. Much of the bay around the vents is corrosive to calcium carbonate; the north shore has a gradient in seawater carbonate chemistry that is well suited to studies of the effects of long-term increases in CO2 levels. This shoreline lacks toxic compounds (such as H2S) and has a gradient in carbonate saturation states.
    Description: Published
    Description: 485–494
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: ocean acidification ; carbon capture and storage ; marine geochemistry ; carbonate saturation state ; volcanic vents ; carbon dioxide ; 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
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  • 78
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    Evidence for a recent change in the shallow plumbing system of Mt. Etna (Italy): Gas geochemistry and structural data during 2001–2005 (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: We analyzed crater SO2 fluxes from Mt Etna, together with soil CO2 effluxes from the volcano's flanks, in the period from 2001 to 2005. Between the 2001 and 2002–2003 eruptions, persistently low values of both parameters suggest that no new gas-rich magma was accumulating at shallow depth (b5 km) within Etna's central conduit, whereas very high SO2 sin-eruptive fluxes during the two eruptions indicated sudden decompression of an un-degassed magma rising along newly-formed eccentric conduits. In November 2003, soil CO2 data indicate migration of gas-rich magma from deep (〉10 km) to shallow (b5 km) portions of the feeding conduits, preceded by an increase in crater SO2 fluxes. A similar behavior was observed also during and after the following 2004–2005 eruption. This degassing style matches a period of increased structural instability of the volcanic edifice caused by acceleration of spreading that affected both its eastern and southern flanks. Spreading could have triggered progressively deeper depressurization in the central conduit, inducing release of the more soluble gas (SO2) first, and then of CO2, contrary to what was observed before the 2001 eruption. This suggests that the edifice has depressurized, promoting ascent of fresh-magma and increasing permeability favouring release of CO2 flux. By integrating geochemical and structural data, previous degassing models developed at Mt. Etna have been updated to advance the understanding of eruptive events that occurred in recent years.
    Description: This work was funded by grants from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and from the Dipartimento per la Protezione Civile (Italy).
    Description: Published
    Description: 90-97
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: 3.6. Fisica del vulcanismo
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Geochemical modeling ; volcano monitoring ; volcanic gases ; Tectonics and magmatism ; flank collapse ; 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::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. 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::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 79
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    The attenuation mechanism of S-waves in the source zone of the 1999 Chamoli earthquake (2013)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: In the present study the attenuation mechanism of seismic wave energy in and around the source area of the Chamoli earthquake of 29th March 1999 is estimated using the aftershock data. Most of the analyzed events are from the vicinity of the Main Central Thrust (MCT), which is a well-defined tectonic discontinuity in the Himalayas. Separation of intrinsic (Q 1 i ) and scattering (Q 1 s ) attenuation coefficient is done over the frequencies 1, 2, 4, 8 and 16 Hz using Multiple Lapse Time Window Analysis (MLTWA) method. It is observed that S-waves and their coda are primarily attenuated due to scattering attenuation and seismic albedo is very high at all the frequencies. A comparison of attenuation characteristics obtained using these aftershock data with those obtained using data of general seismicity of this region reveal that at lower frequencies both intrinsic and scattering attenuation for Chamoli was much higher compared to those for Garwhal-Kumaun region using general seismicity data. At higher frequencies intrinsic attenuation for Chamoli is lower than and scattering attenuation is comparable to those obtained using general seismicity data of Garwhal-Kumaun region.
    Description: A partial support has been given by Italy INGV-DPC (Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento di Protezione Civile) Projects UNREST and SPEED, and by Italy’s Ministry of Education PRIN project (Seismic Hazard in Central Apennines, UR Del Pezzo).
    Description: Published
    Description: 446-454
    Description: 1T. Geodinamica e interno della Terra
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: JCR Journal
    Description: restricted
    Keywords: MLTWA ; Intrinsic attenuation ; Scattering attenuation ; Chamoli Himalayas ; Himalayas ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 80
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    Response of the shallow aquifer of the volcano-hydrothermal system during the recent crises at Vulcano Island (Aeolian Archipelago, Italy) (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2017-04-04
    Description: The shallow thermal aquifer at Vulcano Island is strongly affected by deep volcanic fluids. The most significant variations were observed during the 1989–1996 crisis due to a large input of steam and acidic gases from depth. Besides chemical variations related to the input of deep fluids, the record of the water-table elevation at monitored wells has provided remarkable insights into the pressure conditions of the volcano-hydrothermal system. After the pressure drop due to the extensive vaporization of the hydrothermal aquifer, occurred after 1993, the volcano-hydrothermal system has been re-pressurized since 2001, probably because of the contribution of volatiles from the hydrothermal-magmatic source. The increase in fluid pressure may have caused reopening of fractures (which had self-seated during the previous period of cooling) and the onset of a phase of higher vapor output in the fumarole field later in 2004. The fracture opening would have promoted further vapor separation from the deep fluid reservoir (hypothesized at 0.5–1.5 km depth) and finally the drainage of S-rich fluids into the shallow thermal aquifer (found out at few tens of meters of depth). The monitoring of both the water chemistry and the water-table elevation provides insights into the eventual pressurization of the volcano-hydrothermal system that precedes the fracture opening and the extensive drainage of deep fluids. The findings of this study could represent crucial information about the stability of the volcano edifice, and lead to reliable techniques for determining the risk of or even predicting phreatic explosions.
    Description: Published
    Description: 70-80
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrothermal system ; Vulcano Island ; Fluid pressure ; Thermal wells ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 81
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    Evidence of a recent rapid subsidence in the S–E Cyclades (Greece): An effect of the 1956 Amorgos earthquake? (2012)
    Elsevier Science Limited
    Details
    Publication Date: 2022-11-23
    Description: An underwater geomorphological survey along the coasts of six Cycladic islands (Sifnos, Antiparos, Paros, Naxos, Iraklia and Keros) revealed widespread evidence of a recent 30–40 cm submergence, part of which may have seismic origin. Comparison with information reported from earthquakes having affected the area suggests that at least part of the recent submergence might be an effect of the 1956 Amorgos earthquake. Modelling of the co-seismic and short-term post-seismic effects of the earthquake revealed that part of the observed subsidence may be explained in some of the islands by a fast post-seismic relaxation of a low-viscosity layer underlying the seismogenic zone. However far-field observations are underestimated by our model, and may be affected by a wider deformation field induced by the largest aftershock of the Amorgos sequence, or by other earthquakes.
    Description: Published
    Description: 27-40
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: tidal notch ; sea level change ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
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  • 82
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    Neogene–Quaternary evolution of the central Apennine orogenic system (Italy): a structural and palaeomagnetic approach in the Molise region (2008)
    Elsevier
    Details
    Publication Date: 2022-05-30
    Description: We report on new palaeomagnetic and magnetic fabric analyses of mainly Upper Miocene sedimentary sequences from the external central Apennine fold and thrust belt (Molise area), where the principal compressive structures are clearly non-coaxial. The sampling was carried out on the E–W-oriented Matese–Frosolone thrust sheet, that for its geographical position and structural setting (superposition of thrusting, strike-slip and extensional tectonics since Late Miocene to present-day) represents a key structure for the comprehension of the Neogene–Quaternary evolution of the entire Molise area. Palaeomagnetic results suggest that the Matese–Frosolone thrust sheet counterclockwise rotated at least 35° after Messinian times. These data confirm that the present-day trend variability observed in the main compressional structures in the Apennine chain can be related to rotations about vertical axes rather than to changes in the stress field orientation, at least since Late Miocene times. Magnetic fabric analyses indicate that the studied sediments were subjected to very mild deformation, suggesting that the surface emergence of the thrust front of the Matese–Frosolone unit is located farther north, far from the studied area. Well-defined magnetic lineations of tectonic origin were only observed in sites close to localised belts of strike-slip deformation.
    Description: Published
    Description: 143-157
    Description: JCR Journal
    Description: reserved
    Keywords: Apennines ; palaeomagnetism ; anisotropy of magnetic susceptibility ; structural geology ; Neogene ; 04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 83
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    Fluid geochemistry and geothermometry in the western sector of the Sabatini Volcanic District and the Tolfa Mountains (Central Italy) (2011)
    Elsevier
    Details
    Publication Date: 2024-05-09
    Description: A geochemical survey of 197 fluid discharges (cold and thermal waters and bubbling pools) and 15 gas emissions from the western sector of the Sabatini Volcanic District and the Tolfa Mountains (Latium, Central Italy) was carried out in 2007–2008. The chemical and isotopic compositions of the fluid discharges indicate the occurrence of two main sources: 1) relatively shallow aquifers with Ca(Na,K)–HCO3 and Ca(Mg)–HCO3 compositions when trapped in volcanic and sedimentary formations, respectively; and 2) a deep reservoir, which is hosted in the Mesozoic carbonate sequence, rich in CO2 and having a Ca–SO4(HCO3) composition. Dissolution of a CO2-rich gas phase into the shallow aquifers produces high-TDS and high-pCO2 cold waters, while oxidation of deep-derived H2S to SO4 2− generates low-pH (b4) sulfate waters. The δ13C–CO2 values for gas emissions (from−2.8 to+2.7‰vs. VPDB) suggest that the origin of CO2 associated with the deep fluids ismainly related to thermo-metamorphic reactions within the carbonate reservoir, although significant mantle contribution may also occur. However, R/Ra values (0.37–0.62) indicate that He is mainly produced by a crustal source, with a minor component from a crust-contaminated mantle. On the basis of the δ13C–CH4 and δD–CH4 values (from −25.7 to −19.5‰ vs. VPDB and from −152 to −93.4‰ vs. VSMOW, respectively) CH4 production is associated with thermogenic processes, possibly related to abiogenic CO2 reduction within the carbonate reservoir. The δ34S–H2S values (from+9.3 to +10.4‰ vs. VCDT) are consistent with the hypothesis of a sedimentary source of sulfur from thermogenic reduction of Triassic sulfates. Geothermometric evaluations based on chemical equilibria CO2–CH4 and, separately, H2S suggest that the reservoir equilibriumtemperature is up to ~300 °C. The δDand δ18O data indicate thatwater recharging both the shallow and deep aquifers has a meteoric origin. Fluid geochemistry, coupled with gravimetric data and tectonic lineaments, supports the idea that significant contributions from a deep-seated geothermal brine are present in the Stigliano thermal fluid discharges. Exploration surveys investigated this area during 70's–90's for geothermal purposes. Nevertheless, presently the area is still under-exploited. The presence of thermal waters and anomalous heat flow together with the demographic growth of the last years,makes this site a suitable location for direct applications of the geothermal resource.
    Description: Published
    Description: 160-181
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Geochemistry Water Gas Stable isotope Geothermometry Central Italy ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 84
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    The Domuyo volcanic system: An enormous geothermal resource in Argentine Patagonia (2014)
    Elsevier Science Limited
    Details
    Publication Date: 2024-05-09
    Description: A geochemical survey of the main thermal waters discharging in the southwestern part of the Domuyo volcanic complex (Argentina),where the latest volcanic activity dates to 0.11 Ma, has highlighted the extraordinarily high heat loss from this remote site in Patagonia. The thermal water discharges are mostly Na-Cl in composition and have TDS values up to 3.78 g L−1 (El Humazo). A simple hydrogeochemical approach shows that 1,100 to 1,300 kg s−1 of boiling waters, which have been affected by shallow steam separation, flow into the main drainage of the area (Rio Varvarco). A dramatic increase of the most conservative species such as Na, Cl and Li from the Rio Varvarco fromupstreamto downstreamwas observed and related solely to the contribution of hydrothermal fluids. The equilibrium temperatures of the discharging thermal fluids, calculated on the basis of the Na-K-Mg geothermometer, are between 190 °C and 230 °C. If we refer to a liquid originally at 220 °C (enthalpy = 944 J g−1), the thermal energy release can be estimated as high as 1.1±0.2 GW, a value that ismuch higher than the natural release of heat in other important geothermal fields worldwide, e.g., Mutnovsky (Russia), Wairakei (New Zealand) and Lassen Peak (USA). This value is the second highest measured advective heat flux from any hydrothermal system on Earth after Yellowstone.
    Description: Published
    Description: 71–77
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Domuyo volcano ; Argentine Patagonia ; Geothermal potential ; Water geochemistry ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 85
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    Carbon-bearing gas geothermometers for volcanic-hydrothermal systems (2013)
    Elsevier Science Limited
    Details
    Publication Date: 2024-05-09
    Description: The genetic relationship between carbon-bearing species (CO, CO2, CH4, C2H6, C3H8, C2H4 and C3H6) was investigated in volcanic-hydrothermal gases emitted from Nisyros (Greece), Vesuvio, La Solfatara (Campi Flegrei) and Pantelleria (all Italy). Apparent carbon isotopic temperatures of the CH4-CO2 system are ~360°C at Nisyros, 420-460°C at Vesuvio, ~450°C at La Solfatara and ~540°C at Pantelleria. These temperatures are confirmed by measured propene/propane and H2/H2O concentration ratios. CH4 and CO2 equilibrate in the single liquid phase prior to the onset of boiling, whereas propene and propane attain equilibrium in the saturated water vapor phase. Boiling in these high-enthalpy hydrothermal systems might occur isothermally. Once vapor has been extracted from the parental liquid, CO/CO2 responds most sensitively to the temperature gradient encountered by the ascending gases. Our results imply that the CH4-CO2 isotopic geothermometer can provide reliable information about temperatures of deep hydrothermal liquids associated with volcanism. Propene/propane and H2/H2O concentration ratios should be measured along with the carbon isotopic composition of CO2 and CH4 to provide independent constraints on the geological significance of the apparent carbon isotopic temperatures.
    Description: Published
    Description: 66–75
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrocarbons ; Hydrothermal fluids ; Volcanoes ; Geothermometry ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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