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  • 04. Solid Earth::04.08. Volcanology::04.08.01. Gases  (38)
  • 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology  (25)
  • 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring  (20)
  • Inversion
  • Elsevier Science Limited  (54)
  • Seismological Society of America  (23)
  • Soc. Explorat. Geophys.  (9)
  • Wiley  (7)
  • 3
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  • 1
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    Seismological Society of America
    Publication Date: 2018-03-12
    Description: The paper has not any abstract
    Description: Published
    Description: 720-727
    Description: 2T. Sorgente Sismica
    Description: 1IT. Reti di monitoraggio
    Description: JCR Journal
    Keywords: Earthquake ; Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2020-10-29
    Description: Turrialba volcano lies in the southern sector of the Central American Volcanic Front (CAVF) in Costa Rica. The geochemistry of major and trace elements, and Sr and Nd isotopes of a selected suite of volcanic rocks ranging in composition from basaltic andesite to dacite and belonging to the last 10 ka of activity of Turrialba volcano is described, together with the He-, Ne-, and Ar-isotope compositions of fluid inclusions hosted in olivine and pyroxene crystals. Most of the variability in the rock chemistry is consistentwith typical trends of fractional crystallization, but there is an outlying group of andesites that displays an adakite-like composition (with a consistent depletion in high-field-strength elements and a marked enrichment in Sr) and low 3He/4He ratios (7.0–7.2 Ra). The trace-element composition of these rocks is typical of subduction-related magmas influenced by an OIB-like component at the source associated with the subduction of the Galapagos seamounts. The 87Sr/86Sr (0.703612–0.703678) and 143Nd/144Nd (0.512960–0.512984) ratios of the bulk rocks vary within narrowranges, and are among the least-radiogenic isotope signatures of the CAVF volcanoes. The 3He/4He ratios measured in fluid inclusions hosted in olivine crystals (up to 8.1 Ra) are among the highest for the CAVF, and indicate that radiogenic 4He from fluids derived fromthe subducting slab contribute negligibly to the mantle wedge. The difference in He isotopes between most of studied rocks and those showing adakite-like features reasonably reflects two distinct components in the local mantle: (1) a MORB-like component, characterized by the highest He-isotope ratios (7.8–8.1 Ra), and (2) an OIB-like component, characterized by lower He-isotope ratios (7.0–7.2 Ra), coming from the subduction of the Galapagos seamounts. An overview at the regional scale indicates that high He-isotope ratios are peculiar to the two extreme sectors of the CAVF (Costa Rica to the south and Guatemala to the north), whereas in the central sector (Nicaragua) the magma source is probably contaminated by slab fluids. For the past few years Turrialba volcano has been in a volcanic unrest phase that has included a series of explosions, the most recent of which occurred between October 2014 and May 2015. The volcano is subject to an ongoing safety alert due to the possibility of a magmatic eruption. One of the crucial questions to be addressed is the kind of eruption that can be expected, and hence what type of magma is likely to be involved. The high 3He/4He ratios (7.8–8.0 Ra) measured during 2011 at high-temperature fumaroles of Turrialba craters are comparable to those measured in fluid inclusions of basaltic andesites that erupted in 1864–1866, suggesting that the magma currently feeding the shallow plumbing system has similar geochemical characteristics to the most recently erupted magma.
    Description: Published
    Description: 319-335
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Turrialba ; 3He/4He ratio ; Fluid inclusions ; Adakite ; MORB mantle ; OIB mantle ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 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
    Publication Date: 2021-05-12
    Description: This study presents a series of self-correcting models that are obtained by integrating information about seismicity and fault sources in Italy. Four versions of the stress release model are analyzed, in which the evolution of the system over time is represented by the level of strain, moment, seismic energy, or energy scaled by the moment. We carry out the analysis on a regional basis by subdividing the study area into eight tectonically coherent regions. In each region, we reconstruct the seismic history and statistically evaluate the completeness of the resulting seismic catalog. Following the Bayesian paradigm, we apply Markov chain Monte Carlo methods to obtain parameter estimates and a measure of their uncertainty expressed by the simulated posterior distribution. The comparison of the four models through the Bayes factor and an information criterion provides evidence (to different degrees depending on the region) in favor of the stress release model based on the energy and the scaled energy. Therefore, among the quantities considered, this turns out to be the measure of the size of an earthquake to use in stress release models. At any instant, the time to the next event turns out to follow a Gompertz distribution, with a shape parameter that depends on time through the value of the conditional intensity at that instant. In light of this result, the issue of forecasting is tackled through both retrospective and prospective approaches. Retrospectively, the forecasting procedure is carried out on the occurrence times of the events recorded in each region, to determine whether the stress release model reproduces the observations used in the estimation procedure. Prospectively, the estimates of the time to the next event are compared with the dates of the earthquakes that occurred after the end of the learning catalog, in the 2003–2012 decade.
    Description: Italian Dipartimento della Protezione Civile in the framework of the 2007–2009 Agreement with Istituto Nazionale di Geofisica e Vulcanologia (INGV), project S1: Analysis of the seismic potential in Italy for the evaluation of the seismic hazard.
    Description: Published
    Description: 147-168
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: point process ; probabilistic forecasting ; interevent time distribution ; seismogenic sources ; Bayesian inference ; 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::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2021-03-12
    Description: tGeological studies and morphological analysis, compared with seismological and geodetic data, suggestthat a compressive regime currently occurs at crustal depth in the western sector of Mt. Etna, accommo-dated by shallow thrusting and folding at the front of the chain, south of the volcanic edifice. In particular,a large WSW-ENE trending anticline, interpreted as detachment fold, is growing west and north of Cata-nia city (the Catania anticline). Geological data suggest that during the last 6000 years the frontal foldhas been characterized by uplift rates of ∼6 mm/yr along the hinge, consistent with the interferometricdata (10 mm/yr) recorded in the last 20 years. Moreover, a NNW-SSE oriented axis of compression hasbeen obtained by seismological data, consistent with GPS measurements over the last 20 years whichhave revealed a shortening rate of ∼5 mm/yr along the same direction. Besides the activity related to thevolcanic feeding system, the seismic pattern under the Mt. Etna edifice can be certainly related to theregional tectonics. The compressive stress is converted into elastic accumulation and then in earthquakesalong the ramps beneath the chain, whereas on the frontal area it is accommodated by aseismic defor-mation along an incipient detachment within the clayish foredeep deposits. The high rate of shorteningat the aseismic front of the chain, suggests a greater “seismic efficiency” in correspondence of ramps atthe rear.
    Description: Published
    Description: 32-41
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Etna ; sicilian basal thrust ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2021-01-07
    Description: Ambrym volcano, in the Vanuatu arc, is one of the most active volcanoes of the Southwest Pacific region, where persistent lava lake and/or Strombolian activity sustains voluminous gas plume emissions. Here we report on the first comprehensive budget for the discharge ofmajor,minor, trace and radioactive volatile species fromAmbrymvolcano, as well as the first data for volatiles dissolved in its basaltic magma (olivine-hosted melt inclusions). In situ MultiGAS analysis of H2O, CO2, SO2 and H2S in crater rim emissions, coupled with filter-pack determination of SO2, halogens, stable and radioactive metals demonstrates a common magmatic source for volcanic gases emitted by its two main active craters, Benbow and Marum. These share a high water content (~93 mol%), similar S/Cl, Cl/ F, Br/Cl molar ratios, similar (210Po/210Pb) and (210Bi/210Pb) activity ratios, as well as comparable proportions in most trace metals. Their difference in CO2/SO2 ratio (1.0 and 5.6–3.0, respectively) is attributed to deeper gasmelt separation at Marum (Strombolian explosions) than Benbow (lava lake degassing) during our measurements in 2007. Airborne UV sensing of the SO2 plume flux (90 kg s−1 or 7800 tons d−1) demonstrates a prevalent degassing contribution (~65%) of Benbow crater in that period and allows us to quantify the total volatile fluxes duringmedium-level eruptive activity of the volcano. Results reveal that Ambrym ranks among the most powerful volcanic gas emitters on Earth, producing between 5% and 9% of current estimates for global subaerial volcanic emissions of H2O, CO2, HCl, Cu, Cr, Cd, Au, Cs and Tl, between 10% and 17% of SO2, HF, HBr, Hg, 210Po and 210Pb, and over 30% of Ag, Se and Sn. Global flux estimates thus need to integrate its contribution and be revised accordingly. Prodigious gas emission from Ambrym does not result from an anomalous volatile enrichment nor a differential excess degassing of its feedingbasalt: this latter contains relativelymodest dissolved amounts ofH2O(≤1.3wt%), CO2 (~0.10 wt%), S (0.075 wt%) and Cl (0.05 wt%), and its degassing under prevalent closed-systemconditions well reproduces the composition of emitted volcanic gases. Instead,we show that the gas discharge is sustained by a very high basalt supply rate of 25m3 s−1, from a large (~ 0.5 km3)magma reservoir probably emplaced at ~3.8 km depth below the summit caldera according to both the H2O-CO2 content of bubble-free melt inclusions and preliminary seismic data. Radioactive disequilibria in the volcanic gases constrain that this reservoir may be entirely renewed in about 240 days. The comparatively low magma extrusion rate requires extensive convective overturn of the basaltic magma column and recycling of the unerupted (denser) degassed magma in the plumbing system, in agreement with textural features of erupted products. Finally, our results suggest that the Indian MORB-type mantle source of Ambrym basalts is modestly enriched in slab-derived water and other volatiles, in agreement with the prevalent volcanoclastic nature of subducted sediments and their lower subduction rate under the central Vanuatu arc due to its collision with the D'Entrecasteaux Ridge.
    Description: Published
    Description: 378-402
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Ambrym ; Vanuatu ; Volatile fluxes ; Magma degassing budget ; Magma reservoir ; Radioactive disequilibria ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2021-05-12
    Description: Slip rate is a critical parameter for describing geologic and earthquake rates of known active faults. Although faults are inherently three-dimensional surfaces, the paucity of data allows for estimating only the slip rate at the ground surface and often only few values for an entire fault. These values are frequently assumed as proxies or as some average of slip rate at depth. Evidence of geological offset and single earthquake displacement, as well as mechanical requirements, show that fault slip varies significantly with depth. Slip rate should thus vary in a presumably similar way, yet these variations are rarely considered. In this work, we tackle the determination of slip rate depth distributions by applying the finite element method on a 2D vertical section, with stratification and faults, across the central Apennines, Italy. In a first step, we perform a plane-stress analysis assuming visco-elasto-plastic rheology and then search throughout a large range of values to minimize the RMS deviation between the model and the interseismic GPS velocities. Using a parametric analysis, we assess the accuracy of the best model and the sensitivity of its parameters. In a second step, we unlock the faults and let the model simulate 10 kyr of deformation to estimate the fault long-term slip rates. The overall average slip rate at depth is approximately 1.1 mm/yr for normal faults and 0.2 mm/yr for thrust faults. A maximum value of about 2 mm/yr characterizes the Avezzano fault that caused the 1915, Mw 7.0 earthquake. The slip rate depth distribution varies significantly from fault to fault and even between neighbouring faults, with maxima and minima located at different depths. We found uniform distributions only occasionally. We suggest that these findings can strongly influence the forecasting of cumulative earthquake depth distributions based on long-term fault slip rates.
    Description: Project “Abruzzo” (code: RBAP10ZC8K_ 003) funded by the Italian Ministry of Education, University and Research (MIUR).
    Description: Published
    Description: 1T. Geodinamica e interno della Terra
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: slip rate ; numerical model ; fault ; rheology ; central Italy ; active tectonics ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 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::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2017-04-04
    Description: This work presents the results of an extensive geochemical survey aimed at measuring soil CO2 effluxes and soil temperatures over a large portion of Mt. Etna's summit area, coupled with an updated structural survey of the same area. The main goals of this study were i) to find concealed or hidden volcano-tectonic structures in the studied area by detecting anomalous soil gas emissions, ii) to investigate the origin of the emitted gas and the mechanism of gas and heat transport to the surface, iii) to produce a structural model based both on the surface geology and on the soil gas data and, lastly, iv) to contribute to the assessment of hazard from slope failure and crater collapses at Mt. Etna. The results revealed many concealed structural lines that followed the major directions of structural weakness in the summit area of Mt. Etna, mostly due to a combined action of gravitational spreading of the volcano and magma intrusions. Both recent and old volcano-tectonic lines were found to act as pathways for the leakage of magmatic gases to the surface. An important role in driving magmatic gases to the surface is also played by fracturing and faulting due to caldera-forming collapses and smaller crater collapses. Correlation between soil CO2 emissions and soil temperature allowed discriminating areas of active shallow hydrothermal circulation along deep fractures (characterized by high values of both parameters, but mostly soil temperature) from those affected by undeveloped fractures that did not reach the surface (characterized by high CO2 emissions at low temperature). The former corresponded to weak zones of the volcano edifice that were frequently site of past eruptions, indicating that those areas keep a high potential for future opening of eruptive fissures. The latter were likely related to sites where new eruptive fissures may open in the near future due to backward propagation of extensional tectonic stress.
    Description: project CGL2005-07509/CLI, Ministry of Education and Science of Spain; DPC-INGV project FLANK; Istituto Nazionale di Geofisica e Vulcanologia — Osservatorio Etneo, Sezione di Catania
    Description: Published
    Description: 79-98
    Description: 5A. Energia e georisorse
    Description: JCR Journal
    Description: restricted
    Keywords: Mt. Etna ; Soil CO2 ; Soil temperature ; Hidden faults ; Structural framework ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2017-04-04
    Description: The carbon dioxide emissions of volcanoes have been targeted as effective contributors of CO2 to the atmosphere. However, different sources can be effective and active at the same time in the generation and release of CO2 in volcanic zones. Since isotopic fingerprinting of CO2 allows the precise identification of different sources, coupling carbon isotope and CO2 flux measurements enables the evaluation of the mass contribution of each source to the carbon dioxide emissions. This paper accounts for the first extensive spatial analysis of coupled measurements of carbon isotopologues of CO2 in the soil gases and CO2 fluxes discharged by soils on Vulcano Island. An innovative method has been designed, tested and fine-tuned in the laboratory to measure δ13C(CO2) values directly in field using a new type of laser-based isotopologues analyzer, namely a DeltaRay™ (Thermo Fisher Scientific). The method can be used to determine the carbon isotope composition across the full range of CO2 concentrations in the soil gases (0 – 100 vol%). These data have been combined with measurements of the CO2 contents in the soil gases to distinguish CO2 from deep origins from CO2 of biogenic origin in the inhabited area of Vulcano Porto. The method of evaluating the amount of deep-origin CO2 in the soil gases is widely applicable in volcanic and geothermal zones for evaluation and monitoring purposes for both gas and volcanic hazards.
    Description: Published
    Description: 59-70
    Description: 4V. Vulcani e ambiente
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Carbon dioxide ; CO2 flux ; CO2 soil degassing ; CO2 isotope composition ; Volcano monitoring ; Vulcano Island (Aeolian Islands) ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2020-05-27
    Description: We use wet-clay analogue models to investigate how pre-existing discontinuities (i.e. structures inherited from previous tectonic phases) affect the evolution of a normal fault at the Earth's surface. To this end we first perform a series of three reference experiments driven by a 45° dipping master fault unaffected by pre-existing discontinuities to generate a mechanically isotropic learning set of models. We then replicate the experiment six times introducing a 60°-dipping precut in the clay cake, each time with a different attitude and orientation with respect to an initially-blind, 45°-dipping, master normal fault. In all experiments the precut intersects the vertical projection of the master fault halfway between the center and the right-hand lateral tip. All other conditions are identical for all seven models. By comparing the results obtained from the mechanically isotropic experiments with results from experiments with precuts we find that the surface evolution of the normal fault varies depending on the precut orientation. In most cases the parameters of newly-forming faults are strongly influenced. The largest influence is exerted by synthetic and antithetic discontinuities trending respectively at 30° and 45° from the strike of the master fault, whereas a synthetic discontinuity at 60° and an antithetic discontinuity at 30° show moderate influence. Little influence is exerted by a synthetic discontinuity at 45° and an antithetic discontinuity at 60° from the strike of the master fault. We provide a ranking chart to assess fault-to-discontinuity interactions with respect to essential surface fault descriptors, such as segmentation, vertical-displacement profile, maximum displacement, and length, often used as proxies to infer fault properties at depth. Considering a single descriptor, the amount of deviation induced by different precuts varies from case to case in a rather unpredictable fashion. Multiple observables should be taken into consideration when analyzing normal faults evolving next to pre-existing discontinuities.
    Description: Published
    Description: 157-175
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: partially_open
    Keywords: Fault growth ; normal fault ; pre-existing discontinuity ; wetclay analogue model ; 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::04.04. Geology::04.04.11. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: We present new real-time measurements of the CO2 concentration and δ13C made from July 16 to 20, 2014 in diluted gases of the active plume emitted by the Central Craters at Mount Etna volcano, Italy. This innovative study involved measuring 13C in plume gases at a very high frequency over 5 days of measurements. The carbon-isotope composition calculated for volcanic CO2 ranged from –1.3‰ to +1.5‰, with uncertainties in the repeated single measurements (i.e., made over periods from 4 to 20 min) that were generally 〈0.7‰, and yet surprisingly varied by larger amounts over the 5-day study period. The range of calculated 13C values mostly overlaps with that indicated for the plume of the Central Craters obtained by discrete sampling and using the isotope-ratio mass spectrometry technique (–2.5‰ 〈 13C 〈 –0.5‰). However, we propose that during particular conditions of volcanic activity, the carbon-isotope composition of CO2 degassed from magma can reach values (up to +1.5‰) that are higher than those reported previously. During this campaign we also made simultaneous measurements of the CO2 and SO2 concentrations using the MultiGAS technique. The volcanic 13C and CO2/SO2 ratios exhibited similar trends over the 5 days of measurements, with the ratios of both tracers peaking on July 16, possibly as a result of the early degassing of CO2 while an eruption was ongoing at Mount Etna. The observed variations and the highest 13C values measured at Mount Etna during this campaign lead to new questions about the variability of this geochemical tracer. The comparisons with the CO2/SO2 ratio also confirm that monitoring 13C in plume gases in real time, coupled to other geochemical tracers, is important for elucidating the magma dynamics at depth.
    Description: Published
    Description: 182-191
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: d13C ; CO2 concentration ; real-time measurements ; Crater plume ; CO2/SO2 ratio ; Mount Etna volcano ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2022-05-25
    Description: The composition and fluxes of volcanic gases released by persistent open-vent degassing at Bromo Volcano, east Java (Indonesia), were characterised in September 2014 from both in-situ Multi-GAS analysis and remote spectroscopic (dual UVcamera)measurements of volcanic plumeemissions. Our results demonstrate that Bromo volcanic gas is water-rich (H2O/SO2 ratios of 56–160) and has CO2/SO2 (4.1 ± 0.7) and CO2/Stot (3.2 ± 0.7) ratios within the compositional range of other high-temperature magma-derived gases in Indonesia. H2/H2O and H2S/SO2 ratios constrain a magmatic gas source with minimal temperature of ~700 °C and oxygen fugacity of 10-17–10-18 bars. UV camera sensing on September 20 and 21, 2014 indicates a steady daily mean SO2 output of 166 ± 38 t d−1, which is ten times higher than reported from few previous studies. Our results indicate that Bromo ranks amongst the strongest sources of quiescent volcanic SO2 emission measured to date in Indonesia, being comparable to Merapi volcano in central Java. By combining our results for the gas composition with the SO2 plume flux, we assess for the first time the fluxes of H2O (4725 ± 2292 t d−1), CO2 (466 ± 83 t d−1), H2S (25 ± 12 t d−1) and H2 (1.1 ± 0.8) from Bromo. Our study thus contributes a new piece of information to the still limited data base for volcanic gas emissions in Indonesia, and confirms that much remain to be done to fully assess the contribution of this very active arc region to global volcanic gas fluxes.
    Description: Published
    Description: 206-213
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Bromo volcano ; Volcanic gases ; SO2 and CO2 fluxes ; Tengger Caldera ; Eastern Java, Indonesia ; Multi-GAS ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2024-05-09
    Description: The Principal Cordillera of Central Chile is characterized by two belts of different ages and lithologies: (i) an eastern Mesozoic belt, consisting of limestone- and gypsum-rich sedimentary rocks at the border between Central Chile and Argentina, where the active volcanic arc occurs; and (ii) a western belt of Cenozoic age containing basaltic to andesitic volcanic and volcanoclastic sequences. This distinctive geological setting controls water chemistry of cold and thermal springs in the region, which are fed by meteoric water that circulates through deep regional structures. In the western sector of Principal Cordillera, water–rock interaction processes produce lowTDS, slightly alkaline HCO3 − dominatedwaters, although dissolution of underlyingMesozoic evaporitic rocks occasionally causes SO4 2− and Cl− enrichments. In this area, few Na+–HCO3 − and Na+–SO4 2− waters occurred, being likely produced by a Ca2+–Na+ exchange during water–rock interactions. Differently, the chemical features of Ca2+–Cl−waterswas likely related to an albitization–chloritization process affecting basaltic to andesitic rocks outcropping in this area. Addition of Na+–Cl− brines uprising from the eastern sector through the westverging thrust faults cannot be excluded, as suggested by the occurrence of mantle He (~19%) in dissolved gases. In contrast, in the eastern sector of the study region, mainly characterized by the occurrence of evaporitic sequences and relatively high heat flow,mature Na+–Cl− waters were recognized, the latter being likely related to promising geothermal reservoirs, as supported by the chemical composition of the associated bubbling and fumarolic gases. Their relatively low3He/4He ratios (up to 3.9 Ra)measured in the fumaroles on this area evidenced a significant crustal contamination by radiogenic 4He. The latter was likely due to (i) degassing from 4He-rich magma batches residing in the crust, and/or (ii) addition of fluids interacting with sedimentary rocks. This interpretation is consistent with the measured δ13C-CO2 values (from−13.2 to−5.72‰vs. V-PDB) and the CO2/3He ratios (up to 14.6 × 1010), which suggest that CO2 mostly originates from the limestone-rich basement and recycling of subducted sediments,with an important addition of sedimentary (organic-derived) carbon,whereas mantle degassing contributes at a minor extent. According to geothermometric estimations based on the Na+, K+, Mg2+ and Ca2+ contents, the mature Na+–Cl− rich waters approached a chemical equilibrium with calcite, dolomite, anhydrite, fluorite, albite, K-feldspar and Ca- andMg-saponites at a broad range of temperatures (up to ~300 °C) In the associated gas phase, equilibria of chemical reactions characterized by slowkinetics (e.g. sabatier reaction) suggested significant contributions from hot and oxidizing magmatic gases. This hypothesis is consistent with the δ13C-CO2, Rc/Ra, CO2/3He values of the fumarolic gases. Accordingly, the isotopic signatures of the fumarolic steam is similar to that of fluids discharged from the summit craters of the two active volcanoes in the study area (Tupungatito and Planchón–Peteroa). These results encourage the development of further geochemical and geophysical surveys aimed to provide an exhaustive evaluation of the geothermal potential of these volcanic–hydrothermal systems.
    Description: Published
    Description: 97-113
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: Fluid geochemistry ; Central Chile ; Water–gas–rock interaction ; Hydrothermal reservoir ; Geothermal resource ; Volcanoes ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2024-05-09
    Description: This study presents the first geochemical data of fluid discharges collected from February 2010 to March 2015 from the Planchón–Peteroa–Azufre Volcanic Complex (PPAVC), located in the Transitional Southern Volcanic Zone (TSVZ) at the border between Argentina and Chile. During the study period, from January 2010 to July 2011, Peteroa volcano experienced phreatic to phreatomagmatic eruption possibly related to the devastating Maule earthquake occurred on February 27, 2010. The compositional dataset includes low temperature (from 43.2 to 102 °C) gas discharges from (i) the summit of Peteroa volcano and (ii) the SE flank of Azufre volcano, both marked by a significant magmatic fluid contribution, as well as bubbling gases located at the foothill of the Peteroa volcanic edifice, which showed a chemical signature typical of hydrothermal fluids. In 2012, strong compositional changes affected the Peteroa gases fromthe summit area: the acidic gas species, especially SO2, increased, suggesting an input of fluids from magma degassing. Nevertheless, the R/Ra and δ13C–CO2 values decreased, which would imply an enhanced contribution from a meteoric-hydrothermal source. In 2014–2015, the chemical and isotopic compositions of the 2010–2011 gases were partially restored. The anomalous decoupling between the chemical and the isotopic parameters was tentatively interpreted as produced by degassing activity from a small batch of dacitic magma that in 2012 masked the compositional signature of the magmatic fluids released from a basalticmagma that dominated the gas chemistry in 2010–2011. This explanation reliably justifies the observed geochemical data, although the mechanisms leading to the change in time of the dominatingmagmatic fluid source are not clear. At this regard, a geophysical survey able to provide information on the location of the two magma batches could be useful to clarify the possible relationships between the compositional changes that affected the Peteroa fluid discharges and the 2010–2011 eruptive activity.
    Description: Published
    Description: 41-53
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: volcanic gas geochemistry ; degassing model ; isotope geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
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  • 14
    Publication Date: 2021-05-12
    Description: In this paper we present a morphotectonic study of the Paganica–San Demetrio fault system (PSDFS) responsible for the Mw6.1 April 6, 2009 earthquake (L'Aquila, Central Italy). The discrepancy observed between the length of the seismologic–geodetic modeled fault, the limited size of the primary coseismic surface ruptures and the significant morphological expression of the PSDFS stimulated a debate about the maximum rupture length of the PSDFS and its capability to generate larger magnitude events. To image the PSDFS long-term morphological expression and define its surface geometrical arrangement (length, number of fault splays and boundaries), we took advantage of a high-resolution airborne LiDAR dataset. LiDAR topography substantially increased our confidence in detecting even subtle tectonic-controlled morphologies. We define the PSDFS as a ~ 19 km-long fault system that displays a complex structural setting characterized by two different sectors: 1) the Paganica sector to the NW, with a narrow deformation zone, and 2) the San Demetrio sector to SE, where the strain is accommodated by several fault-splays dissecting a wider Quaternary basin. We also defined a first-order hierarchy among the numerous fault splays across the PSDFS. The long-term geomorphic expression of the PSDFS suggests that it ruptured also involving the whole 19 km-long structure besides rupturing only small sections, as it occurred in 2009. This suggests a variable slip behavior. Empirical relations applied to this hypothesis allow up to M 6.6 earthquakes along the PSDFS. These results have a critical impact on the seismic hazard assessment of the area when compared with a M 6.1 event as the 2009.
    Description: Published
    Description: 108-121
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Active normal faulting; Tectonic geomorphology; Airborne LiDAR; 2009 L'Aquila earthquake ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
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  • 15
    Publication Date: 2021-03-01
    Description: The Greek necropolis of Abakainon (NE Sicily, southern Italy) was destroyed suddenly, some time after the 2nd century BC. In order to identify the destruction cause of the necropolis, we analyzed geological, geomorphological data, and site stratigraphy. Evidence on the site suggests that the observed collapse and deformation may be consistent with a seismic event. Optically Stimulated Luminescence dating constrains the age of the collapse to the 1st century AD, probably during the time-span 14e37 AD, when other nearby sites were also damaged by an earthquake, as reported by historical sources. This study contributes to a better characterization of earthquakes in the area during the first millennium AD and improves knowledge on historical seismicity in NE Sicily.
    Description: Published
    Description: 190-199
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: archaeoseismology ; historical seismology ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
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  • 16
    Publication Date: 2021-03-04
    Description: Macroseismic investigation with data collected through web- based questionnaires is today routinely applied by most impor- tant seismological institutions, such as the U.S. Geological Survey (http://earthquake.usgs.gov/earthquakes/dyfi/; last accessed December 2014), British Geological Survey (http://www. earthquakes.bgs.ac.uk/questionnaire/EqQuestIntro.html; last accessed December 2014), European-Mediterranean Seismological Centre (http://www.emsc-csem.org/Earthquake/Contribute/ choose_earthquake.php?lang=en; last accessed December 2014), Schweizerische Erdbebendienst (http://www.seismo.ethz. ch/eq/detected/eq_form/index_EN; last accessed December 2014), Bureau Central Sismologique Français (http://www .seisme.prd.fr/english.php; last accessed December 2014), and the New Zealand GeoNet project (http://www.geonet.org.nz/ quakes/; last accessed December 2014). The wide diffusion of Internet and the citizen collaboration (crowdsourcing) allow documentation of information on seismic effects and production of a macroseismic field with low costs and almost in real time. Transformation from qualitative information (as given by ques- tionnaires) to numerical quantification is a crucial issue. In the traditional evaluation of intensity, experts used to work through a complex comparison of effects basically driven by personal expe- rience. The major problem with this approach concerns the dif- ficulty in verifing and reproducing the evaluation process due to the lack of a detailed explanation of the employed workflow and to the large variability of possible cases. On the other hand, an automatic method for the estimation of macroseismic intensities needs to be completely well defined and specified in order to be reproducible and verifiable. For these reasons, this paper presents a comprehensive explanation of our intensity assessment method. A useful automatic method for intensity assessment should be computationally fast and strictly follow the macroseismic scales. To meet these requirements in 2010, we proposed a method that firstly quantified the effects using additive scores associated with each answer of the questionnaire item and then determined an intensity estimate for each questionnaire (Sbarra et al., 2010). After a trial period and having collected more than 500,000 questionnaires, we were able to thoroughly test the method. As a result of this testing, we describe here a new improved method that takes into account further factors, such as the situation and the location of the observer (Sbarra et al., 2012, 2014), to obtain a more accurate estimate of the macroseismic intensity degree at the municipality level. In this paper, we show some applications of our method with reference to the Mercalli–Cancani–Sieberg (MCS) scale, because this scale has long been used with Italian earthquakes and allows easy comparison between these intensities and other traditional ones.
    Description: Published
    Description: 985-990
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 5T. Sorveglianza sismica e operatività post-terremoto
    Description: 4IT. Banche dati
    Description: JCR Journal
    Description: reserved
    Keywords: Macroseismics ; intensity ; questionnaires ; attenuation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
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  • 17
    Publication Date: 2021-03-05
    Description: In summer 2013 a toxic and polluting gas blowout (19 tonnes day−1 CO2, 95 kg day−1 CH4) occurred from two shallow boreholes drilled at only 50 m from the International Airport of Rome (Italy), in the town of Fiumicino. Another gas blowout occurred in the same period from a borehole located offshore, 2 km away, also generating sea-water acidification; it lasted only a couple of days. Onshore, CO2was also diffusing fromholes within the soil, particularly toward the airport, generating a soil flux up to 1.8 tonnes day−1. In 3.5 months ~1500 tonnes of CO2 and 5.4 tonnes of CH4 were emitted in the atmosphere. Temporal monitoring of gas geochemistry indicates that in this area a mixing occurs between shallow and pressurized gas pockets, CO2-dominated, but with different chemical (i.e., He/CH4 ratio) and isotopic (3He/4He, δ13C-δDCH4) characteristics. Numerical simulation of CO2 dispersion in the atmosphere showed that dangerous air CO2 concentrations, up to lethal values, were only found near the vents at a height of 0.2 m. Fiumicino is a high blowout risk area, as CO2 rising through deep reaching faults pressurizes the shallowaquifer contained in gravels confined underneath shales of the Tiber delta deposits. The Fiumicino blowout is a typical example of dangerous phenomenon that may occur in urban context lying nearby active or recent volcanoes and requires quick response on hazard assessment by scientists to be addressed to civil protection and administrators.
    Description: Published
    Description: 54-65
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Endogenous gas blowout from shallow wells ; Chemical and isotopic composition of gas and water ; Viscous flux and diffuse soil gas flux measurements ; Simulation andmonitoring of air CO2 dispersion ; Hazard assessment ; 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::04.08.07. Instruments and techniques ; 05. General::05.08. Risk::05.08.01. Environmental risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2021-03-04
    Description: We investigate the influence of building height on the ability of people to feel earthquakes and observe that, in an urban area, short and tall buildings reach different levels of excitation. We quantify this behavior by analyzing macroseismic reports collected from individuals through the Internet, focusing on transitory effects, therefore in the elastic regime during recent earthquakes in Italy in the local magnitude (ML) range of 3 to 5.9. We find a maximum difference of 0.6 intensity units between the top floors of tall (7–10 stories) and short (1–2 stories) buildings at the highest considered magnitudes. As expected, tall buildings experience greater shaking than short buildings during large earthquakes at large source distances. However, we observe the opposite behavior at close distances when the ML is less than 3.5. These results can be explained by considering the different spectra radiated by small and large earthquakes and the different fundamental mode resonances of buildings (i.e., shorter buildings have higher resonance frequencies and vice versa). Using idealized building models excited by real acceleration time histories, we compute synthetic accelerograms on the top floors of short and tall buildings, and confirm the trend of the observed differences in felt intensities.
    Description: Published
    Description: 1803-1809
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: Macroseismics ; intensity ; building height ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 19
    Publication Date: 2021-06-03
    Description: We investigate the Middle Aterno Valley fault system (MAVF), unknown poorly investigated seismic gap in the central Apennines, adjacent to the 2009 L’Aquila earthquake epicentral area. Geological and paleoseismological analyses revealed that the MAVF evolved through hanging wall splay nucleation, its main segment moving at 0.23-0.34 mm/year since the Middle Pleistocene; the penultimate activation event occurred between 5388-5310 B.C. and 1934-1744 B.C., the last event after 2036-1768 B.C. and just before 1st-2nd century AD. These data define hard linkage (sensu Walsh and Watterson, 1991; Peacock et al., 2000; Walsh et al., 2003, and references therein) with the contiguous Subequana Valley fault segment, able to rupture in large magnitude earthquakes (up to 6.8), that did not rupture since about two millennia. By the joint analysis of geological observations and seismological data acquired during to the 2009 seismic sequence, we derive a picture of the complex structural framework of the area comprised between the MAVF, the Paganica fault (the 2009 earthquake causative fault) and the Gran Sasso Range. This sector is affected by a dense array of few-km long, closely and regularly spaced Quaternary normal fault strands, that are considered as branches of the MAVF northern segment. Our analysis reveals that these structures are downdip confined by a decollement represented by to the presently inactive thrust sheet above thef Gran Sasso front limiting their seismogenic potential. Our study highlights the advantage of combining Quaternary geological field analysis with high resolution seismological data to fully unravel the structural setting of regions where subsequent tectonic phases took place and where structural interference plays a key role in influencing the seismotectonic context; this has also inevitably implications for accurately assessing seismic hazard of such structurally complex regions.
    Description: Published
    Description: 186–198
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Quaternary geological survey ; paleoseismology ; vertically restricted faults ; structural interference ; capable faulting ; Abruzzo ; Central Italy ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2017-04-04
    Description: An automatic analysis code called ANISOMAT+ has been developed and improved to automatically retrieve the crustal anisotropic parameters fast polarization direction (ϕ) and delay time (δt) related to the shear wave splitting phenomena affecting seismic S-wave. The code is composed of a set of MatLab scripts and functions able to evaluate the anisotropic parameters from the three-component seismic recordings of local earthquakes using the cross-correlation method. Because the aim of the code is to achieve a fully automatic evaluation of anisotropic parameters, during the development of the code we focus our attention to devise several automatic checks intended to guarantee the quality and the stability of the results obtained. The basic idea behind the development of this automatic code is to build a tool able to work on a huge amount of data in a short time, obtaining stable results and minimizing the errors due to the subjectivity. These behaviors, coupled to a three component digital seismic network and a monitoring system that performs automatic pickings and locations, are required to develop a real-time monitoring of the anisotropic parameters.
    Description: Published
    Description: 62-68
    Description: 1T. Geodinamica e interno della Terra
    Description: 2T. Tettonica attiva
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Description: 3IT. Calcolo scientifico e sistemi informatici
    Description: JCR Journal
    Description: restricted
    Keywords: shear wave splitting, Earthquake forecast, Anisotropy, Cross-correlation method ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
    Publication Date: 2020-02-24
    Description: We present a coupled fluid-dynamic and electromagnetic model for volcanic ash plumes. In a forward approach, the model is able to simulate the plume dynamics from prescribed input flow conditions and generate the corresponding synthetic thermal infrared (TIR) image, allowing a comparison with field-based observations. An inversion procedure is then developed to retrieve vent conditions from TIR images, and to independently estimate the mass eruption rate. The adopted fluid-dynamic model is based on a one-dimensional, stationary description of a self-similar turbulent plume, for which an asymptotic analytical solution is obtained. The electromagnetic emission/absorption model is based on Schwarzschild's equation and on Mie's theory for disperse particles, and we assume that particles are coarser than the radiation wavelength (about 10 μm) and that scattering is negligible. In the inversion procedure, model parameter space is sampled to find the optimal set of input conditions which minimizes the difference between the experimental and the synthetic image. Application of the inversion procedure to an ash plume at Santiaguito (Santa Maria volcano, Guatemala) has allowed us to retrieve the main plume input parameters, namely mass flow rate, initial radius, velocity, temperature, gas mass ratio, entrainment coefficient and their related uncertainty. Moreover, by coupling with the electromagnetic model we have been able to obtain a reliable estimate of the equivalent Sauter diameter of the total particle size distribution. The presented method is general and, in principle, can be applied to the spatial distribution of particle concentration and temperature obtained by any fluid-dynamic model, either integral or multidimensional, stationary or time-dependent, single or multiphase. The method discussed here is fast and robust, thus indicating potential for applications to real-time estimation of ash mass flux and particle size distribution, which is crucial for model-based forecasts of the volcanic ash dispersal process.
    Description: Published
    Description: 129–147
    Description: 3V. Dinamiche e scenari eruttivi
    Description: 4V. Vulcani e ambiente
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Volcanic ash plume ; Volcanic ash plume ; Thermal camera ; Inversion ; Mass flow ; Particle size ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous
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  • 22
    Publication Date: 2020-05-27
    Description: Several mountainous regions are currently affected by syn- or post-orogenic active extension. We investigate how a newly-formed normal fault interacts with structures inherited from a previous contractional phase. To this end, we use analog models that adopt an innovative technique for performing a precut that mimics such inherited structures into a clay layer; this clay layer is laid on top of a master fault simulated by two rigid blocks sliding along an inclined plane. We carry out six experiments with variously oriented precuts and compare the results with those obtained in a reference isotropic experiment. All other conditions are identical for all seven realizations. Fault evolution is monitored by taking closely-spaced snapshots analyzed through the Digital Image Correlation method. We find that the upward propagation of the normal fault can be either accelerated or decelerated depending on the presence of a precut and its orientation. Such precuts can also promote or inhibit the formation of bending-moment faults. These interactions between master fault and precut also affect the shape of the fault-related syncline-anticline pair.
    Description: Published
    Description: 145–158
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Extension ; Normal faults ; Pre-existing fault ; Analogue modeling ; Accommodation space ; Blind fault ; Active tectonics ; 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::04.06.01. Earthquake faults: properties and evolution
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  • 23
    Publication Date: 2017-04-04
    Description: Naples is a large city located between two active volcanic areas: Campi Flegrei to theWand Vesuvius to the SE. The Solfatara crater, inside the caldera of the Campi Flegrei and nearest to the western quarters of the city, is a prodigious source of natural CO2 with a mean emission rate of 1067 ton/d, i.e. seven times higher than that of Vesuvius(151 ton/d). This study shows that the area around the Solfatara and part of the urban area of Naples are affected by the volcanic plume when atmospheric circulatory patterns are dominated by the locally frequent sea breezes. Under these conditions the CO2 content in the air increases above normal values, reaching more than 1000 ppm in proximity to the Solfatara crater to a few tens of ppm several kilometres from the source. Although these values do not indicate a health risk even under the most unfavourable atmospheric conditions, the volcanic source contributes to the total CO2 burden from all urban emissions and hence to overall air quality. An emission rate ten times higher than the present one would lead to an air CO2 concentration in excess of recommended health protection thresholds.
    Description: Published
    Description: 52-61
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: CO2 dispersion; Solfatara; Gas hazard; Campi Flegrei ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 24
    Publication Date: 2017-04-04
    Description: We installed a permanent SO2 camera system on Stromboli, Italy, in May 2013, in order to improve our capacity to monitor the SO2 emissions from this volcano. The camera collects images of SO2 concentrations with a period of ~ 10 s, allowing quantification of short-term processes, such as the gas released during the frequent explosions which are synonymous with Stromboli. It also allows quantification of the quiescent gas flux, and therefore comparison with the FLAME network of scanning ultraviolet spectrometers previously installed on the island. Analysis of results from the SO2 camera demonstrated a good agreement with the FLAME network when the plume was blown fully into the field of view of the camera. Permanent volcano monitoring with SO2 cameras is still very much in its infancy, and therefore this finding is a significant step in the use of such cameras for monitoring, whilst also highlighting the requirement of a favourable wind direction and strength. We found that the explosion gas emissions are correlated with seismic events which have a very long period component. There is a variable time lag between event onset time and the increase in gas flux observed by the camera as the explosion gas advects into the field of view of the camera. This variable lag is related to the plume direction, as shown by comparison with the plume location detected with the FLAME network. The correlation between explosion gas emissions and seismic signal amplitude show is consistent with a gas slug-driven mechanism for seismic event production. Comparison of the SO2 camera measurements of the quiescent gas flux shows a fair quantitative agreement with the SO2 flux measured with the FLAME network. Overall, the SO2 camera complements the FLAME network well, as it allows frequent quantification of the explosion gas flux produced by Stromboli, whose signal is in general too brief to be measured with the FLAME network. Further work is required, however, to fully automate the calculation of SO2 flux from the SO2 images captured with the camera, and to adequately account for scattering effects.
    Description: Published
    Description: 95-102
    Description: 3V. Dinamiche e scenari eruttivi
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Stromboli ; SO2 flux ; VLP ; Explosion ; SO2 camera ; volcano monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 25
    Publication Date: 2022-05-04
    Description: The 600 m-thick Gole Larghe Fault Zone (GLFZ) is hosted in jointed crystalline basement and exposed across glacier-polished outcrops in the Italian Alps. Ancient seismicity is attested by the widespread occurrence of cataclasites associated with pseudotachylytes (solidified frictional melts) formed at 9–11 km depth and ambient temperatures of 250–300 °C. Previous work focused on the southern part of the fault zone; here we quantitatively document fault zone structure across the full width of the GLFZ and surrounding tonalite host rocks by using a combination of structural line transects and image analysis of samples collected across fault strike. These new datasets indicate that the GLFZ has a broadly symmetric across-strike damage structure and contains distinct southern, central and northern zones distinguished by large variations in fracture density, distribution of pseudotachylytes, volume of fault rock materials, and microfracture sealing characteristics. The c. 100 m wide central zone is bound by two thick (~ 2 m) and laterally continuous (〉 1 km) protocataclastic to ultracataclastic horizons. Within and immediately surrounding the central zone, fracture density is relatively high due to cataclastic fault–fracture networks that reworked earlier-formed pseudotachylytes. The fault–fracture networks were associated with pervasive microcracking and fluid–rock interaction, resulting in the development of a c. 200 m thick alteration zone delimited by lobate fluid infiltration fronts. In the c. 250 m thick southern and northern zones, fracture densities are much lower and pseudotachylytes systematically overprint cataclastic faults that exploited pre-existing magmatic cooling joints. Analysis of the structure of the GLFZ suggests that it shares certain characteristics with the seismogenic source responsible for the 2002 Au Sable Forks intraplate earthquake sequence in the northeastern USA, including seismicity distributed across a fault zone 500–1000 m thick and large (〉 100 MPa) static stress drops associated with frictional melting.
    Description: Published
    Description: 29-44
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: JCR Journal
    Description: reserved
    Keywords: Fault structure ; Fluid flow ; Fracture damage ; Alteration ; Cataclasite ; Adamello ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
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  • 26
    Publication Date: 2021-12-16
    Description: In extending areas undergoing regional tectonic uplift, the persistence of subsidence at a normal-fault hanging-wall depends on the competition between regional and local tectonic effects. When regional uplift exceeds the subsidence of the hanging-wall block, denudation prevails at both the hanging-wall and the foot-wall. When local tectonic subsidence exceeds regional uplift, sedimentation occurs over the hanging-wall block, supplied by foot-wall erosion. We analyzed a PlioceneeQuaternary continental basin, currently crossed by the Tiber River in Italy. The tectono-sedimentary evolution of the basin developed at the hanging-wall of a regional low-angle extensional detachment, the Alto Tiberina Fault, in the axial region of the Northern Apennines of Italy. This area is affected by regional uplift on the order of 0.5e1.0 mm/yr. The present-day activity of the fault is revealed by both microseismicity and geodetic (GPS) data. We investigated the mid- (10e100 ka) and long-term (0.5e3.0 Ma) evolution of the three depocenters by studying the continental Pleistocene succession infilling the basin as well as fluvial terraces and higher paleosurfaces carved into the Pleistocene deposits. By using surficial geologic data and an interpretation of a set of seismic reflection profiles, we show that the three depocenters experienced a fairly similar evolution during the PlioceneeEarly Pleistocene, when a 1000-m-thick continental succession was deposited. On the contrary, geomorphological observations indicate that, at the beginning of the Middle Pleistocene, a switch occurred in the evolution of the three depocenters. In the northernmost Sansepolcro sub-basin, bounding normal faults are active and hanging-wall subsidence outpaces regional uplift. Concurrently, in the Umbertide and Ponte Pattoli subbasins uplift dominates over the hanging-wall subsidence, promoting river incision and exhumation of the Pleistocene deposits. For these two depocenters, by means of terrace-river correlations, we estimate that the incision rate is ~0.3e0.35 mm/yr, suggesting a maximum tectonic subsidence of 0.2 mm/yr. The identification of a heterogeneous uplift pattern along the hanging-wall of the Alto Tiberina Fault, driven by different displacement rates of its fault splays, allowed us to characterize fault segments with different activities and, possibly, different seismic behaviors.
    Description: Published
    Description: 111-132
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Quaternary basin ; normal fault ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 27
    Publication Date: 2023-01-16
    Description: With this short communication we address the principal issues raised by Delmelle et al. (2014) in relation to the work of Bagnato et al. (2013) concerning the 2010 eruption of Eyjafjallajo¨ kull, Iceland. The principal conclusions of the work of Bagnato et al. (2013) include the observation that protracted gas-aerosol interaction in the plume promotes selective leaching of cation species from ash, with alkalis and Ca (and, among trace elements, Zn and Cu) being more rapidly re-mobilized (and transferred to soluble surface salts) relative to more inert elements (Mg, Ti). They also observed that adsorption onto ash surfaces is a major atmospheric sink of volcanic acidic gases, with 282 tons of elemental sulfur and 605–691 tons of halogens being daily ground deposited via ash over Iceland in early May 2010. Acidic gas adsorption onto ash increases almost linearly with plume aging (e.g., upon increasing in-plume residence times of ash and gases), and is seen to proceed at about 3 time faster rates for HF than for SO2 and HCl. However, Delmelle et al. (2014) criticized our strategies for data acquisition, processing and interpretation. They also raised some objections concerning several key topics explored by Bagnato et al. (2013), with a special focus on the discussion of rates of interaction between ash particles and gases in a volcanic cloud, and the consequent formation of soluble salts on ash surfaces. They also considered incorrect the estimate of depositional fluxes and volatile budget for the Eyjafjallajo¨ kull eruption. While we appreciate the in-depth analysis of Delmelle et al. (2014), we show that most of their criticisms derive from a partial and sometimes incorrect understanding of the work of Bagnato et al. (2013), which overall led to unsupported conclusions and misleading analysis of the original results. Here, we present a detailed response to the comments of Delmelle et al. (2014), accompanied by additional explicative material. The principal conclusions presented in Bagnato et al. (2013) are given additional support by this complementary note.
    Description: Published
    Description: 385-389
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Eyjafjallajokull ; sulfur, halogens and trace metals ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
    Publication Date: 2024-02-01
    Description: We calculate Plio-Pleistocene slip rates on the blind thrusts of the outer Northern Apennines fronts, that are the potential sources of highly damaging earthquakes, as shown by the MW 6.1-6.0, 2012 Emilia-Romagna seismic sequence. Slip rates are a key parameter for understanding the seismogenic potential of active fault systems and assessing the seismic hazard they pose, however, they are difficult to calculate in slow deforming areas like the Po Plain where faulting and folding is mostly blind. To overcome this, we developed a workflow which included the preparation of a homogeneous regional dataset of geological and geophysical subsurface information, rich in Plio- Pleistocene data. We then constructed 3D geological models around selected individual structures to decompact the clastic units and restore the slip on the fault planes. The back-stripping of the differential compaction eliminates unwanted overestimation of the slip rates due to compactioninduced differential subsidence. Finally, to restore the displacement we used different methods according to the deformation style, i.e. Fault Parallel Flow for faulted horizons, trishear and elastic dislocation modeling for fault-propagation folds. The result of our study is the compilation of a slip rate database integrating former published values with 28 new values covering a time interval from the Pliocene to the present. It contains data on 14 individual blind thrusts including the Mirandola thrust, seismogenic source of the 29 May 2012, MW 6.0 earthquake. Our study highlights that the investigated thrusts were active with rates ranging between 0.1-1.0 mm/yr during the last 1.81 Myr. The Mirandola thrust slipped at 0.86±0.38 mm/yr during the last 0.4 Myr. These rates calculated with an homogeneous methodology through the entire Po Plain can be charged entirely to the thrust activity and not to secondary effects like the differential compaction of sediments across the structures.
    Description: Published
    Description: 8–25
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Blind thrusts ; Slip rates ; 3D geological modeling ; Sediment decompaction ; Po Plain ; Northern Apennines ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2024-05-09
    Description: We have analyzed the carbon isotopic composition of CO2, methane, ethane, propane and n-butane, the hydrogen isotopic composition of methane as well as total concentrations of gas constituents contained in theMediterranean volcanic–hydrothermal discharges of Nisyros (Greece), Vesuvio, La Solfatara, Ischia and Pantelleria (all Italy) to determine the origin of the hydrocarbons. Isotopic criteria conventionally used for hydrocarbon classification suggest thermogenic origins, except for Pantelleria, for which an abiogenic origin is indicated. These findings would imply that thermogenic sources can provide methane/(ethane + propane) concentration ratios as high as those usually observed for microbial hydrocarbons. However, additional consideration of gas concentration data challenges the suitability of conventional criteria for the classification of hydrocarbons emanating from hydrothermal environments. Methane seems to be in close equilibrium with co-occurring CO2, whereas its higher chain homologues are not. Therefore, it cannot be excluded that methane on the one hand and ethane, propane and n-butane on the other hand have distinct origins. The carbon isotopic composition of methane might be controlled by the carbon isotopic composition of co-occurring inorganic CO2 and by hydrothermal temperatures whereas the carbon isotopic composition of the higher n-alkanes could correspond to the maturity of organic matter and/or to the residence time of the gasses in the source system
    Description: Published
    Description: 152–163
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Hydrocarbons ; Abiogenic ; Thermogenic ; Stable isotopes ; Fumaroles ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
    Publication Date: 2021-06-22
    Description: Total CO2 output from soil gas and plume, discharged from the Stromboli Island, was estimated. The CO2 emission of the plume emitted from the active crater was estimated on the basis of the SO2 crater output and C/S ratio, while CO2 discharged through diffuse soil emission was quantified on the basis of 419 measurements of CO2 fluxes from the soil of the whole island, performed by using the accumulation chamber method. The results indicate an overall output of ≅416 t day−1 of CO2 from the island. The main contribution to the total CO2 output comes from the summit area (396 t day−1), with 370 t/day from the active crater and 26 t day−1 from the Pizzo sopra La Fossa soil degassing area. The release of CO2 from peripheral areas is ≅20 t day−1 by soil degassing (Scari area mainly). The result of the soil degassing survey confirms the persistence of the highest CO2 degassing areas located on the North-East crater side and Scari area.
    Description: Published
    Description: 52-60
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: CO2 flux ; CO2 output ; Stromboli Island ; SO2 flux ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2017-04-04
    Description: Soil carbonates are key features in soils of arid and semiarid environment, playing an important role from pedogenetic, landscape history, paleoclimatic and environmental points of view. The objectives of this work were (i) to study pathways of pedogenic carbonate (PC) formation, (ii) to distinguish between lithogenic and pedogenic inorganic C by using the natural C isotope abundance, and (iii) to estimate the soil C pools in a gypsiferous semiarid Mediterranean environment (Sicily, Italy). Five soil pedons developed on calcareous and non-calcareous parent materials from Holocene (10,000 years BP) to Upper Tortonian (7.2–5.3 Ma BP) in age were surveyed. During field soil description, the highest stage of carbonate morphology was found in soils developed on non-calcareous Holocene colluvial deposits (youngest deposits in age) which also showed the highest amount of PC. The great amount of PC in soils developed on youngest deposits was ascribed to a soil–landscape relationships. Being located in a doline overhung by gypsum outcrops, precipitation of Ca2+ from gypsum dissolved by rainfall and biogenic CO2 is reliable. The significant positive relationship between soil organic C and pedogenic carbonates δ13C values confirms that PC was formed from biogenic CO2. Organic C pool in the first cubic meter of soil ranged from 17 to 42 kg, whilst pedogenic inorganic C pool from 2.8 to 30.7 kg. The estimated rate of inorganic C accumulation in soils developed on youngest deposits was 2.5 g m−3 y−1, whereas the rate was negligible on older parent material. The hypothesized pathways of PC formation were ex-novo precipitation of gypsum–Ca2+ and biogenic CO2 and dissolution of lithogenic CaCO3 and re-precipitation of Ca2+ with biogenic CO2. From an environmental prospective, investigated soils may act as a sink of C when Ca2+ from gypsum is available for the formation of pedogenic carbonates.
    Description: Published
    Description: 31-38
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: JCR Journal
    Description: restricted
    Keywords: Gypsiferous soils ; Soil carbonates ; Stable C isotopes ; Soil C pools ; Soil–landscape relationship ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: Volatile metal(loid)s are known to be emitted from volcanoes worldwide.We tested the suitability of active moss monitoring for tracking volatilemetal(loid)s released fromthe fumarolic field on Vulcano Island, Italy, and differentiated fumaroles from other sources of gaseous and particulate trace elements such as sea spray and soil.Metal(loid) accumulation on the mosses per day did depend neither on the state of the exposed moss (dead or living) nor exposure time (3, 6, or 9 weeks). After collection, mosses were digested with either HNO3/H2O2 or deionized water and analyzed by ICP-MS.While for most elements both extraction methods yielded similar concentrations, higher concentrations were observed e.g. for Pb in the stronger HNO3/H2O2 extracts, indicating the presence of particles, which were not digested and removed by filtration in deionized water extracts. Due to their ubiquitous detection in comparable concentrations at all 23 moss monitoring stations all over the island, Li, Mg and Sr were attributed to sea spray origin. Iron, Co, W, V, Pb, Cr, Mo, and Ba occurred predominantly at the crater, where the soil was not covered by vegetation, and thus likely represent soil-borne particulate transport. Arsenic, Sb, S, Se, Tl, Bi, and I showed a clear concentration maximum within the fumarolic field. Concentrations gradually decreased along a transect in wind direction fromthe fumaroles, which confirms their volcanic origin. Activemossmonitoring thus proved to be an inexpensive and easy-to-apply tool for investigations of volcanic metal(loid) emissions and distributions enabling differentiation of trapped elements by their source of origin.
    Description: Published
    Description: 30–39
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: La Fossa crater ; particle transport ; biomonitoring ; volatilization ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2017-04-04
    Description: We present a review of our work on data acquired by GEOSTAR-class (GEophysical and Oceanographic STation for Abyssal Research) observatories deployed at three EMSO (European Multidisciplinary Seafloor and water-column Observatory; http://www.emso-eu.org) sites in southern European waters where strong geo-hazards are present: the Western Iberian Margin, the Western Ionian Sea, the Marmara Sea, and the Marsili basin in the Tyrrhenian Sea. A procedure for multiparameter data quality control is described. Then we explain why the seafloor is an interesting observation point for geophysical parameters and how it differs from land sites. We consider four interesting geophysical phenomena found at the EMSO sites that are related to geo-hazard. In the first case, we show how unknown seismicity and landslides in the Western Ionian Sea were identified and roughly localised through a single-sensor analysis based on the seismometer. In the second case, we concentrate on the problem of near-coast tsunami generation and describe a Tsunami Early Warning Detection (TEWD) system, tested in the Western Iberian Margin and currently operating in real time at the Western Ionian site. In the third case, we consider two large volcanoes in the central Mediterranean area, Mt. Etna and the Marsili seamount. Signals from the seismometer and gravimeter recorded at the seafloor at 2100 m b.s.l. show various phases of Mt. Etna's 2002–2003 eruption. For the less-known Marsili we illustrate how several indicators coming from different sensors point to hydrothermal activity. A vector magnetometer at the two volcanic sites helps identify the magnetic lithospheric depth. In the fourth and final case, we present a multiparameter analysis which was focused on finding possible correlations between methane seepage and seismic energy release in the Gulf of Izmit (Marmara Sea).
    Description: Published
    Description: 12–30
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: JCR Journal
    Description: restricted
    Keywords: European Seas ; Geophysical measurements ; Multiparameter seafloor and water-column observatories ; Data quality analysis ; Geo-hazard ; Tsunami early detection ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 34
    Publication Date: 2017-04-04
    Description: In this work we show that the main springs of the central Apennine transport a total amount of heat of ∼2.2 109 J s−1. Most of this heat (57%) is the result of geothermal warming while the remaining 43% is due to gravitational potential energy dissipation. This result indicates that a large area of the central Apennines is very hot with heat flux values 4300 mWm−2. These values are higher than those measured in the magmatic and famously geothermal provinces of Tuscany and Latium and about 1/3 of the total heat discharged at Yellowstone. This finding is surprising because the central Apennines have been thought to be a relatively cold area. Translated by CO2 rich fluids, this heat anomaly suggests the existence of a thermal source such as a large magmatic intrusion at depth. Recent tomographic images of the area support the presence of such an intrusion visible as a broad negative velocity anomaly in seismic waves. Our results indicate that the thermal regime of tectonically active areas of the Earth, where meteoric waters infiltrate and deeply circulate, should be revised on the basis of mass and energy balances of the groundwater systems.
    Description: Published
    Description: 65–74
    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: restricted
    Keywords: heat flux ; CO2 Earth degassing ; central Apennine ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2017-04-04
    Description: We investigate the transfer zone and linkage between divergent extensional seismogenic fault systems on the border amid the central and southern Apennines (central Italy). These regional NW-SE striking sets include large seismogenic sources that caused major historical earthquakes (Mw≤7). The faults in the northern part of the study area dip to the southwest; those in the southern part dip to the northeast. The SW-dipping system (Abruzzi Apennines) terminates with the Aremogna-Cinque Miglia source; the NE-dipping system (southern Apennines) terminates with the Boiano Basin source. To test whether the transfer zone model applies to the central-southern Apennines border, we analyzed and relocated seismicity that occurred from 2007 to 2011 between the Aremogna-Cinque Miglia and Boiano Basin sources, where we expect the transfer zone. Seismicity is made of independent events (Md〈3.5) and low-magnitude swarms. West of the Apennines, hypocenters are located within the uppermost 12-13 km. Events and swarms that occurred east of the axis affect the 13-25 km below. West of the chain, focal mechanisms show T-axes striking ~NNW-SSE. East of the chain, T-axes strike ~NE-SW. This trend is consistent with GPS data. The hypocentral distribution of swarms located between the Aremogna-Cinque Miglia and Boiano Basin sources shows a ~NNE-SSW trend, coincident with part of the Ortona-Roccamonfina Line, a regional transverse lineament. The spatial distribution of seismicity, the geometry and kinematics of active faulting in the region, and results from previous geophysical studies, allow us to contend the existence of a transfer zone between these seismogenic normal fault systems. Our data also allow us to recognize the activity of such transfer along the central part of the Ortona-Roccamonfina Line. We infer that reverse in dip polarity between the two normal fault systems could also result from the passage between the diverse tectonic units composing the border between central and southern Apennines.
    Description: Published
    Description: 18-31
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: seismogenic sources ; seismic swarms ; transverse lineaments ; fault polarity ; transfer zone ; southern italy ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 36
    Publication Date: 2022-06-10
    Description: Between January 2011 and April 2012, Santorini volcano (Greece) experienced a period of unrest characterised by the onset of detectable seismicity and caldera-wide uplift. This episode of inflation represented the first sizeable intrusion of magma beneath Santorini in the past 50 years. We employ a new approach using 222 Rn– δ 13 C systematics to identify and quantify the source of diffuse degassing at Santorini during the period of renewed activity. Soil CO 2 flux measurements were made across a network of sites on Nea Kameni between September 2010 and January 2012. Gas samples were collected in April and September 2011 for isotopic analysis of CO 2 ( δ 13 C), and radon detectors were deployed during September 2011 to measure ( 222 Rn). Our results reveal a change in the pattern of degassing from the summit of the volcano (Nea Kameni) and suggest an increase in diffuse CO 2 emissions between September 2010 and January 2012. High-CO 2 -flux soil gas samples have δ 13 C ∼ 0 .Using this value and other evidence from the literature we conclude that these CO 2 emissions from Santorini were a mixture between CO 2 sourced from magma, and CO 2 released by the thermal or metamorphic breakdown of crustal limestone. We suggest that this mixing of magmatic and crustal carbonate sources may account more broadly for the typical range of δ 13 CvaluesofCO 2 (from ∼− 4 to ∼+ 1 )in diffuse volcanic and fumarole gas emissions around the Mediterranean, without the need to invoke unusual mantle source compositions. At Santorini a mixing model involving magmatic CO 2 (with δ 13 C of − 3 ± 2 and elevated ( 222 Rn)/CO 2 ratios ∼ 10 5 –10 6 Bqkg − 1 )andCO 2 released from decarbonation of crustal limestone (with ( 222 Rn)/CO 2 ∼ 30–300 Bqkg − 1 ,and δ 13 Cof + 5 ) can account for the δ 13 C and ( 222 Rn)/CO 2 characteristics of the ‘high flux’ gas source. This model suggests ∼ 60% of the carbon in the high flux deep CO 2 end member is of magmatic origin. This combination of δ 13 Cand( 222 Rn) measurements has potential to quantify magmatic and crustal contributions to the diffuse outgassing of CO 2 in volcanic areas, especially those where breakdown of crustal limestone is likely to contribute significantly to the CO 2 flux
    Description: Published
    Description: 180-190
    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: restricted
    Keywords: volcanic unrest ; soil gas measurements ; carbon isotopic analysis ; magmatic degassing ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 37
    Publication Date: 2024-05-09
    Description: Copahue volcano is part of the Caviahue–Copahue Volcanic Complex (CCVC),which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina–Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe–Ofqui strike slip and the northern Copahue–Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (δ13C-CO2, δ15N, 3He/4He, 40Ar/36Ar, δ13C-CH4, δD-CH4, and δD-H2O and δ18O-H2O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/Ra up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. δ13C-CO2 values (from −8.8‰ to −6.8‰ vs. V-PDB), δ15N values (+5.3‰ to +5.5‰ vs. Air) and CO2/3He ratios (from 1.4 to 8.8 × 109) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H2O-CO2-CH4-CO-H2 system suggests that CO and H2 re-equilibrate in a separated vapor phase at 200°–220 °C. On the contrary, rock–fluid interactions controlling CO2, CH4 production from Sabatier reaction and C3H8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250° to 300 °C. Fumarole gases sampled in 2006–2007 show relatively low N2/He and N2/Ar ratios and high R/Ra values with respect to those measured in 2012. Such compositional and isotope variations were likely related to injection of mafic magma that likely triggered the 2000 eruption. Therefore, changes affecting the magmatic systemhad a delayed effect on the chemistry of the CCVC gases due to the presence of the hydrothermal reservoir. However, geochemical monitoring activities mainly focused on the behavior of inert gas compounds (N2 and He), should be increased to investigate the mechanism at the origin of the unrest started in 2011.
    Description: Published
    Description: 44–56
    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: restricted
    Keywords: Fluid geochemistry ; Copahue volcano ; Fumarolic fluid ; Hydrothermal reservoir ; Volcanic unrest ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 38
    Publication Date: 2024-05-09
    Description: Measurements of soil fluxes of hydrothermal gases, with special emphasis on C6H6, as well as chemical composition of mono-aromatic compounds in fumaroles and air, were carried out in April 2012 at the Solfatara crater (Campi Flegrei, Southern Italy) to investigate the distribution and behavior of these species as they migrate through the soil from their deep source to the atmosphere. Soil fluxes of CO2, CH4 and C6H6 exhibit good spatial correlation, suggesting that diffuse degassing is mainly controlled by local fractures. The calculated total output of diffuse C6H6 from Solfatara is 0.10 kg day 1, whereas fluxes of CO2 and CH4 are 79 103 and 1.04 kg day 1, respectively. A comparison between soil gas fluxes and fumarole composition reveals that within the crater soil CH4 is significantly affected by oxidation processes, which are more efficient for low gas fluxes, being dependent on the residence time of the uprising hydrothermal gases at shallow depth. Benzene degradation, mainly proceeding through oxidation via benzoate, seems to be strongly controlled by the presence of a shallow SO2 4 -rich aquifer located in the central and southwestern sectors of the crater, suggesting that the process is particularly efficient when SO2 4 acts as terminal electron acceptor (SO4 reduction). Relatively high C6H6/C7H8 ratios, typical of hydrothermal fluids, were measured in air close to the main fumarolic field of Solfatara crater. Here, C6H6 concentrations, whose detection limit is 0.1 lgm 3, are more than one order of magnitude higher than the limit value for ambient air (5 lgm 3). This suggests that hydrothermal fluids have a strong impact on air quality in the immediate surroundings of the fumarolic vents. Significant concentrations of endogenous mono-aromatics were also detected in air samples collected from the northern and western sides of the crater, where these gas compounds are mostly fed by diffuse degassing through the crater bottom soil.
    Description: Published
    Description: 142–153
    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: restricted
    Keywords: hydrothermal gases ; Solfatara crater ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 39
    Publication Date: 2017-04-04
    Description: None
    Description: Published
    Description: 639-648
    Description: 3.10. Storia ed archeologia applicate alle Scienze della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: archaeoseismology, Jericho, neolithic earthquakes, Dead Sea fault, Palestine ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
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  • 40
    Publication Date: 2017-04-04
    Description: Herein we report on the chemical and isotopic (C, H, O, and He) compositions of the fluids from La Fossa crater fumaroles of Vulcano from 1999 to 2010. Consistent with records obtained since the end of the 1980s, our data show that the geochemical features of the fumarole system have experienced several episodes of remarkable change, each lasting no more than a few months. Typical signatures of these short-term anomalies are large increments in CO2, N2, and He concentrations, coupled to increased 13C/12C isotopic ratios, but their meaning remains widely debated. Within a model of fumarolic fluids based on mixing between hydrothermal and magmatic endmembers, we have developed a novel approach to constrain chemical (He/ CO2 and N2/He) and isotopic (13C/12C, D/H, and 3He/4He) ratios of the magmatic endmember during the short-term anomalies. Although much of the geochemical variability in fumaroles results from changes in mixing proportions, the magmatic fluid unquestionably shows significant variations in time. The magmatic He/CO2, N2/He, 13C/12C, and 3He/4He values throughout 1988–1996 differed from those feeding the anomaly at the end of 2004. Early clues of the new magmatic fluid appeared in 1998–1999, far from any short-term anomaly, whereas new and old magmatic fluids coexisted after 2004. We quantitatively prove that the detected geochemical changes are consistent with the degassing path of a magma having a latitic composition, and suggest the presence of two magma ponding levels at slightly different pressures, where bubble–melt decoupling can occur. The different He-isotope compositions at these levels suggest low hydraulic connectivity typical of a complex reservoir with dike and sill structures. In this framework, the short-term geochemical anomalies are probably due to gas accumulation at the top of magma bodies followed by massive escape, or activation of new degassing levels in the reservoir, for which the stress field almost certainly plays a key role. Such a scenario explains the observed increases in both fumarole output and shallow high-frequency seismicity (due to increased pore pressure) during the anomalies, while being consistent with the concomitant absence of any deep seismicity or ground deformation, eventually related to magma movement.
    Description: Published
    Description: 158-178
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: fumarole geochemistry ; magma degassing ; thermodynamic modeling ; noble gas geochemistry ; carbon isotopes ; 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::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 41
    Publication Date: 2017-04-04
    Description: In the present paper, we will describe the field survey (Fig. 1) and the data analysis of an experiment carried out to put constraints on the magnitude detection threshold in the area of Campi Flegrei. Results show that seismic radiation emitted from VT seismic events at frequency lower than 2 Hz has a high detection threshold (minimum magnitude around 1.5). In the range between 2 and 20 Hz, VT events with magnitudes smaller than about 0.5 have a high probability to be undetected. This result indicates that noise reduction through borehole stations and/or small arrays is essential for an accurate seismic monitoring in the Campi Flegrei area.
    Description: Published
    Description: 190-198
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: restricted
    Keywords: seismic noise ; magnitude detection ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
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  • 42
    Publication Date: 2017-04-04
    Description: Herein, we present a method for continuous measurement of soil CO2 flux that is completely new and distinct from existing instruments. The foremost difference is that instead of using an infrared gas analyser (IRGA), the new device measures soil CO2 flux by means of a simple pressure sensor, measuring pressure transients inside a closed polymeric tube inserted into the soil. This allows continuous measurements even in soil placed in environments that could potentially damage IRGA. In addition, due to the innovative operating principle, measurements of soil CO2 flux can be effortlessly performed also in strongly harsh weather conditions. Theoretical equations were derived for calculating soil CO2 flux solely using measured transient values. The reliability of the equations was rigorously tested with a variety of experiments. Continuous measurements over four months, acquired in a high-emission area on the Island of Vulcano, compared favourably with the data obtained using an established method.
    Description: Published
    Description: 102-109
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: restricted
    Keywords: Soil CO2 flux measurements ; Continuous monitoring ; Methods of measurement ; Polymeric membranes ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 43
    Publication Date: 2017-04-04
    Description: Our study is aimed to develop a 3D physical model of the Campi Flegrei geothermal system, in order to achieve a more accurate and comprehensive representation of the hydrothermal processes occurring in the caldera. The new model, developed by using the TOUGH2 code simulator, accounts for the caldera rocks' physical properties, bathymetry and water table topography. In particular, the computational domain is constrained by density values obtained by tomographic inversion of gravity data collected during several surveys at CF both onshore and offshore the caldera. Empirical relations between density and porosity and between porosity and permeability, derived by published data on samples cored in deep wells or collected in outcrops, allowed us to characterize the main rocks physical parameters controlling the dynamic of the CF geothermal system. We have performed and compared several simulations investigating the effects of the injection at depth, underneath Solfatara crater, of a hot gaseous mixture rich in CO2. We show that, with respect to the available literature on 2D axisymmetric models, the effects of the water table topography together with the bathymetry and the heterogeneous distribution of the rocks' physical properties, lead to important differences in the hydrothermal circulation of fluids at CF. These constraints allow the activation of convective cells with different behaviors, which produce variable patterns of temperature inside the hydrothermal system. As a consequence, the predominant effect is again represented by a central plume below the Solfatara crater, but with a non-axisymmetric structure and a wider extension. Additionally, high temperature zones are present near the coastline and in the middle part of the submerged area of the caldera with a SE–NW alignment. Moreover, our results indicate that, the submerged part of the CF caldera would deserve a more accurate study and survey, being affected by phenomenon of heating and degassing. This information could be very useful in terms of hazard assessment and volcanic risk mitigation in such an active and densely inhabited volcanic and geothermal area.
    Description: Published
    Description: 172-182
    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: restricted
    Keywords: Campi Flegrei ; Geothermal system ; 3D model ; Water table topography ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 44
    Publication Date: 2017-04-04
    Description: Epidermis micromorphology of in situ Erica arborea L. exposed for generations to long-term effect of volcanic gases in Pisciarelli and Solfatara di Pozzuoli areas have been studied by X-ray analyses, SEM and TEM observations. In particular, the aim of this study is to investigate the effects of volcanic gases on extant and possibly fossil plants. Plants of the same species living in a nearby control site were also studied for comparison. SEM coupled with EDX analysis was used to localize different elements within the leaves (mesophyll, cell wall and cuticle). After conventional and cryo preparation, SEM of mature leaves ascertained that the abaxial side is more serrate in fumigated leaves and hairs, epicuticular wax alterations have also been noted. Leaves experiencing chronic fumigation display stomata more sunken with respect to the epidermal surface. TEM of transverse and longitudinal sections of cuticle showed an outer A2 granular amorphous layer and external to a B1 fibrillous layer. Significant statistical variations of ultrastructural components of the cuticle revealed a response of E. arborea to this extreme environment. At the ultrastructural level, significant variations in thickness of the cell wall plus cuticle, cell wall and A2 layer among fumigated and non-fumigated leaves have been found. In the studied localities a positive correlation between atmospheric CO2 concentration and the thickness of A2 layer also exists. The results are of interest being applicable in the understanding of plant cuticle responses during periods of normal vs. volcanic activity.
    Description: Published
    Description: 197– 206
    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: restricted
    Keywords: Phlegrean Fields ; Erica arborea ; Volcanic gases ; Epidermis ; Cuticle ultrastructure ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems ; 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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  • 45
    Publication Date: 2017-04-04
    Description: Monitoring damaged buildings in an area where an earthquake has occurred requires the use of techniques which provide rapid and safe measurements even in emergency conditions. In particular, remote sensing techniques like terrestrial laser scanning (TLS) can satisfy these requirements, since they produce very dense point clouds in little time and also allow an accurate geometric modeling of observed buildings. Nevertheless, strong constraints on TLS data acquisition geometry, such as acquisition distance and incidence angles, typically characterize an area in seismic emergency conditions. In order to correctly interpret the data, it is necessary to estimate errors affecting TLS measurements in these critical conditions. A reliable estimation can be achieved by means of experiments and numerical simulations aimed at quantifying a realistic noise level, with emphasis on reduction of artifacts due to data acquisition, registration and modeling. This paper proposes a data analysis strategy in which TLS-based morphological maps computed as point-to-primitive differences are created. The method can be easily used for accurate surveying in emergency conditions. In order to demonstrate the proposed method in very diverse situations, it was applied to rapidly detect deformation traces in the San Giacomo Roncole Campanile (Modena), the Asinelli tower (Bologna) and the Cantalovo Church (Verona), three buildings damaged by the Mw 5.9 Emilia Romagna 2012 earthquake (Italy). 2013 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier
    Description: Published
    Description: 185-198
    Description: 1.10. TTC - Telerilevamento
    Description: JCR Journal
    Description: restricted
    Keywords: Architecture ; Change Detection ; Laser Scanning ; Model ; Performance ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 46
    Publication Date: 2017-04-04
    Description: We present the first chlorine isotope compositional data for gases and lavas from Mount Etna (Italy), and to our knowledge, of active Mediterranean volcanism. We investigated lavas erupted and gases discharged during 2008-2011 from a high-temperature fumarole (HT; 〉300°C) and plume gases from both North East and Central Craters. Most of the samples vary in a narrow range of chlorine isotope composition (37Cl values ≈ 0 ± 0.7‰) with gases partially overlapping with rocks. Only HT gases sampled in 2009 have been clearly affected by secondary processes (37Cl values 〉 15.9‰), resulting in partial removal of chlorine and isotopic fractionation producing a 37Cl enrichment in the residual gaseous HCl. These secondary processes also affect, although to a lesser extent, plume gases from North East Crater (NEC). Although post-magmatic processes are able to modify the chlorine isotope composition, 37Cl values are not affected by magma degassing for residual fractions ≥ 0.3 in the melt, or any effect is within our data variability. Finally, 37Cl values and Cl/K ratios of magmatic chlorine constrain the Etnean source to be compatible with depleted mantle (DMM) contaminated by altered oceanic crust (AOC), in agreement with indications from more common isotopic tracers of mantle processes.
    Description: Published
    Description: 134-142
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Mount Etna ; chlorine isotope ; plume ; fumarole ; degassing ; mantle source ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 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::04.08.05. Volcanic rocks
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  • 47
    Publication Date: 2017-04-04
    Description: Passive samplers were used to measure the atmospheric concentrations of SO2 naturally emitted at three volcanoes in Italy (Etna, Vulcano and Stromboli) and of H2S naturally emitted at three volcanic/geothermal areas in Greece (Milos, Santorini and Nisyros). The measured concentrations and dispersion patterns varied with the strength of the source (open conduits or fumaroles), the meteorological conditions and the area topography. At Etna, Vulcano and Stromboli, SO2 concentrations reach values that are dangerous to people affected by bronchial asthma or lung diseases (〉1000 μg m−3). H2S values measured at Nisyros also exceed the limit considered safe for the same group of people (〉3000 μg m−3). The data obtained using passive samplers represent time-averaged values over periods from a few days up to 1 month, and hence concentrations probably reached much higher peak values that were potentially also dangerous to healthy people. The present study provides evidence of a peculiar volcanic risk associated with tourist exploitation of active volcanic areas. This risk is particularly high at Mt. Etna, where the elderly and people in less-than-perfect health can easily reach areas with dangerous SO2 concentrations via a cableway and off-road vehicles
    Description: Published
    Description: 1-13
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: Sulphur dioxide ; Hydrogen sulphide ; Volcanic risks ; Gas hazard ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 48
    Publication Date: 2017-04-04
    Description: Commenton “CO2 variabilityinmid-oceanridge basalts fromsyn-emplacementdegassing: Constraintsoneruptiondynamics”
    Description: Published
    Description: 251-253
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: non-equilibrium degassing, modeling, CO2, bubble growth, MORB, gas geochemistry ; 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::04.08.04. Thermodynamics
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  • 49
    Publication Date: 2017-04-03
    Description: Fluorine adsorption experiments were performed on 28 samples of the first 5 cm of topsoil collected on the flanks of Mt. Etna. The soil samples were equilibrated with F-rich rainwater (3.25 mg/L) at a soil/water weight ratio of 1/25. Aliquots of the supernatant were collected after 1, 7, 72, 720 and 5640 h and analysed for F content. The soil samples could be subdivided into three groups based on their F-adsorption behaviours after 1 h and at the end of the experiment: (1) negative adsorption (F released from the soil to the solution) after 1 h and negative or moderately positive adsorption at the end, (2) from negative after 1 h to strongly positive adsorption at the end, and (3) always strong positive adsorption. The adsorption capacity of the soils was positively correlated with the soil pH, the contents of finer granulometric fractions (clay and silt) and the weathering stage (as quantified by the chemical alteration index). The most F adsorbing soils are found at the periphery of the volcano where aquifers are more vulnerable to contamination due to the shallower depth of the water table. This study further evidences the importance of the Etnean soils in protecting groundwater from an excessive magmatic F input.
    Description: Published
    Description: 1179–1188
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: restricted
    Keywords: volcanic soils ; fluoride adsorption ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.08. Risk::05.08.01. Environmental risk
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  • 50
    Publication Date: 2017-04-04
    Description: In this paper, we report four years of soil CO2 emission data measured monthly at 130 sites in two peripheral areas of Mt Etna Volcano that are well known for their high discharge rates of volcanic gas. We remove the influence of atmospheric parameters, and by means of statistical analyses, we (i) demonstrate that variations in CO2 emissions are due mainly to CO2 of a deep origin and (ii) quantify the total amounts of CO2 derived from a deep magma source. Periods of anomalous deep degassing are identified in both areas. A comparison of the timing of these anomalies and geophysical data indicates that the periods of anomalous degassing can be mostly ascribed to intrusions of fresh magma into the Etna plumbing system, which is in agreement with many previous works. Based on the existing literature, we formulate an interpretative framework of magma migration within the plumbing system, consistent with temporal trends in the observed anomalies. Finally, we reconstruct the processes of recent magma ascent at Mt Etna based on our interpretative framework, published geophysical data, and records of volcanic activity.
    Description: Published
    Description: 218-227
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Soil CO2 flux ; Mt Etna ; Volcanic activity ; Magma transfer ; 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::04.08.06. Volcano monitoring
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  • 51
    Publication Date: 2017-04-04
    Description: From October 2008 to November 2009, soil CO2, radon and structural field surveys were performed on Mt. Etna, in order to acquire insights into active tectonic structures in a densely populated sector of the south-eastern flank of the volcano, which is involved in the flank dynamics, as highlighted by satellite data (InSAR). The studied area extends about 150 km2, in a sector of the volcano where InSAR results detected several lineaments that were not well-defined from previous geological surveys. In order to validate and better constrain these features with ground data evidences, soil CO2 and soil radon measurements were performed along transects roughly orthogonal to the newly detected faults, with measurement points spaced about 100 m. In each transect, the highest CO2 values were found very close to the lineaments evidenced by InSAR observations. Anomalous soil CO2 and radon values were also measured at old eruptive fractures. In some portions of the investigated area soil gas anomalies were rather broad over transects, probably suggesting a complex structural framework consisting of several parallel volcano-tectonic structures, instead of a single one. Soil gas measurements proved particularly useful in areas at higher altitude on Mt. Etna (i.e. above 900 m asl), where InSAR results are not very informative/ are fairly limited, and allowed recognizing the prolongation of some tectonic lineaments towards the summit of the volcano. At a lower altitude on the volcanic edifice, soil gas anomalies define the active structures indicated by InSAR results prominently, down to almost the coastline and through the northern periphery of the city of Catania. Coupling InSARwith soil gas prospectingmethods has thus proved to be a powerful tool in detecting hidden active structures that do not show significant field evidences.
    Description: This work was funded by the DPC-INGV project “Flank”
    Description: Published
    Description: 27-40
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: CO2 ; Radon ; InSAR ; Faults ; Etna ; Volcano-tectonics ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 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
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  • 52
    Publication Date: 2017-04-04
    Description: The ordinary, low intensity, activity of Stromboli volcano is sporadically interrupted by more energetic events termed, depending on their intensity, “major explosions” and “paroxysms”. These short-lived energetic episodes represent a potential risk to visitors to the highly accessible summit of Stromboli. Observations made at Stromboli over the last decade have shown that the composition of gas emitted from the summit craters may change prior to such explosions, allowing the possibility that such changes may be used to forecast these potentially dangerous events. In 2008 we installed a novel, remote-controlled, open-path FTIR scanning system called Cerberus at the summit of Stromboli, with the objective of measuring gas compositions from individual vents within the summit crater terrace of the volcano with high temporal resolution and for extended periods. In this work we report the first results from the Cerberus system, collected in August-September 2009, November 2009 and May-June 2010. We find significant, fairly consistent, intra-crater variability for CO2/SO2 and H2O/CO2 ratios, and relatively homogeneous SO2/HCl ratios. In general, the southwest crater is richest in CO2, and the northeast crater poorest, while the central crater is richest in H2O. It thus appears that during the measurement period the southwest crater had a somewhat more direct connection to a primary, deep degassing system; whilst the central and northeast craters reflect a slightly more secondary degassing nature, with a supplementary, shallow H2O source for the central crater, probably related to puffing activity. Such water-rich emissions from the central crater can account for the lower crystal content of its eruption products, and emphasise the role of continual magma supply to the shallowest levels of Stromboli's plumbing system. Our observations of heterogeneous crater gas emissions and high H2O/CO2 ratios do not agree with models of CO2-flushing, and we show that simple depressurisation during magma ascent to the surface is a more likely model for H2O loss at Stromboli. We highlight that alternative explanations other than CO2 flushing are required to explain distributions of H2O and CO2 amounts dissolved in melt inclusions. We detected fairly systematic increases in CO2/SO2 ratio some weeks prior to major explosions, and some evidence of a decrease in this ratio in the days immediately preceding the explosions, with periods of low, stable CO2/SO2 ratios between explosions otherwise. Our measurements, therefore, confirm the medium term (~ weeks) precursory increases previously observed with MultiGas instruments, and, in addition, reveal new, short-term precursory decreases in CO2/SO2 ratios. immediately prior to the major explosions. Such patterns, if shown to be systematic, may be of great utility for hazard management at Stromboli's summit. Our results suggest that intra-crater CO2/SO2 variability may produce short-term peaks and troughs in CO2/SO2 time series measured with in-situ MultiGas instruments, due simply to variations in wind direction.
    Description: Published
    Description: 66-76
    Description: JCR Journal
    Description: open
    Keywords: OP-FTIR scanning system ; Stromboli Volcano ; Explosive activity ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
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  • 53
    Publication Date: 2017-04-04
    Description: In this paper we investigate nature and properties of narrow-band, transient seismic signals observed by a temporary array deployed in the Val Tiberina area (central Apennines, Italy). These signals are characterized by spindle-shaped, harmonic waveforms with no clear S-wave arrivals. The first portion of the seismograms exhibits a main frequency peak centred at 4.5 Hz, while the spectrum of the slowly decaying coda is peaked at about 2 Hz. Events discrimination is performed using a matched-filtering technique, resulting in a set of 2466 detections spanning the 2010 January–March time interval. From a plane-wave-fitting procedure, we estimate the kinematic properties of signals pertaining to a cluster of similar events. The repetition of measurements over a large number of precisely aligned seismograms allows for obtaining a robust statistics of horizontal slownesses and propagation azimuths associated with the early portion of the waveforms. The P-wave arrival exhibits horizontal slownesses around 0.1 s km−1, thus suggesting waves impinging at the array almost vertically. Separately, we use traveltimes measured at a sparse network to derive independent constraints on epicentral location. Ray parameters and azimuths are calibrated using slowness measurements from a local, well-located earthquake. After this correction, the joint solution from traveltime inversion and array analysis indicates a source region spanning the 1–3 km depth interval. Considerations related to the source depth and energy, and the occurrence rate which is not related to the daily and weekly working cycles, play against a surface, artificial source. Instead, the close resemblance of these signals to those commonly observed in volcanic environments suggest a source mechanism related to the resonance of a fluid–filled fracture, likely associated with instabilities in the flux of pressurized CO2.
    Description: Published
    Description: 918-928
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Fracture and flow ; Earthquake source observations ; Interface waves ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 54
    Publication Date: 2017-04-04
    Description: Ambrym is one of the most actively erupting basaltic volcanoes in the Vanuatu island arc. Scoria clasts collected from a fallout deposit in the inner terrace of its Benbow active crater were analyzed through series of synchrotron X-ray computed microtomographic experiments, as well as permeability measurements and simulations. Our goal was to reconstruct and visualize scoria textures in 3D and to quantify vesicularity, permeability, vesicle sizes and distributions in order to understand how gas moves in and out of Ambrym basaltic magma. We find that vesicle size distributions in the volume range between ~ 103 and 1010 μm3 define two scoria classes. Vesicle size distributions in the low-to-moderately (0.44–0.67) vesicular samples can be fit by power laws with an exponent of 1 ± 0.2; distributions in the highly vesicular (0.86–0.88) samples can be fit by power laws with a higher exponent (1.4 to 1.7), as well as by exponential fits. Highly vesicular samples exhibit a very pronounced large vesicle, consisting of networks of smaller, interconnected vesicles, that is more than three orders of magnitude larger in volume than all other vesicles in each distribution. This type of vesicle is not found in the low-to-moderately vesicular samples. In addition, vesicle number density negatively correlates with vesicularity: less vesicular samples have the highest number density and vice versa, and contain far more numerous small-to-medium-sized vesicles than highly vesicular samples. Measured and calculated viscous (Darcian) permeabilities overlap in the range 10− 13 and 10− 9 m2, with higher values in the more vesicular samples. We ascribe these differences in the textural and physical properties of the scoria clasts to their derivation from distinct magma portions in the conduit that were driven by convective overturn and underwent different vesiculation histories and gas transport dynamics. Comparing basaltic scoria clasts from Ambrym to those from mild explosive activity at Stromboli volcano (Italy) reveals that differences in their vesicle size distributions may result from the influence of different crystal contents and shapes on the vesiculation and permeability of the respective magmas. Finally, we highlight how rheological properties have a fundamental role in determining the degassing behaviour of basaltic magma at Ambrym and other volcanoes in general.
    Description: Published
    Description: 55-64
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: restricted
    Keywords: Ambrym ; Basaltic scoria ; 3D X-ray micro-tomography analysis ; Volcanic degassing ; Magma convection ; Crystal effect ; 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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 55
    Publication Date: 2017-04-04
    Description: We propose a very detailed picture of the seismicity occurring in the proximity of the Alto Tiberina Low Angle Normal Fault (ATF, Northern Italian Apennines) by presenting the pattern and evolution of a seismic sequence that occurred on the hanging wall of the ATF in the first months of 2010 and that was characterized by about 1000 events with ML ranging from -0.7 to 3.8. In order to capture the rupture kinematics of the investigated area, a cross-correlation technique was at first applied to calculate very accurate time shifts among the events of the sequence and then to relocate them. Considering the many factors that can affect the accuracy of a routine event location, the whole sequence was relocated with the double-difference method, including both absolute travel-time measurements and cross-correlation differential travel-times. The new locations confirm that seismic activity is mainly arranged along a NW-SE oriented structure, ranging in depth from 4 to 6 km and dipping towards North East with an angle of about 65°. A further analysis of waveforms similarity was performed at a reference station by merging the capability of the cross-correlation technique and the bridging algorithm. The analysis allows us to group events into several earthquake families (from now on multiplets), 11 of which include at least 10 events with a cross-correlation value higher than 0.9. The detected mutiplets allow us to emphasize the spatial and temporal migration of the sequence occurred along a 307°N strike direction with an averaged propagation velocity of about 0.4 km/day. The normal focal mechanisms obtained from the events with ML≥2 validate the supposed extensional tectonic regime of the investigated area. The main nodal planes, characterized by strikes ranging in 312°±12 and dips about -90°, are consistent with the spatial evolution of the aftershocks.
    Description: Published
    Description: 91-109
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: cross-correlation ; multiplets ; double-difference ; migration ; pattern ; Alto Tiberina Fault ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
    Publication Date: 2017-04-04
    Description: A 4-year geochemical survey of some fumaroles at the Voragine summit crater of Mt Etna was performed in combination with synchronous monitoring of peripheral gas emissions at the base of the volcano. This was the first geochemical study at Mt Etna to have included the abundances of Ar, He, and C isotopes. Once the effects of postmagmatic shallow processes were identified and quantitatively removed, the He–Ar–CO2 systematics of the Voragine crater fumaroles and peripheral gas emissions described the same degassing path. Combining the carbon-isotope composition with information about noble gases provided evidence that the crater fumaroles are fed from a two-endmember mixture composed of a deep member coming from pressures between 200 and 400 MPa (depending on time), and a shallower one exsolved at 130 MPa. Similar mixing processes probably also occur in gases from peripheral vents. The simultaneous assessment of d13CCO2 and He/Ar values of crater fumaroles over time has identified simple changes in the mixing proportion between the two endmembers and, moreover, periods during which the exsolution pressure of the deep fluid increased. These periods seem to be linked to pre-eruptive phases of the volcano. The identified open-system degassing processes are indicative of efficient bubble–melt decoupling at depth, whereas the mixing process requires a convective transfer of the deeply exsolved fluids toward shallower levels of magma where further vapor is exsolved. In agreement with the most recent geophysical and petrological data from Mt Etna, these observations allow inferences about a deep portion of the plumbing system (5 to 12 km b.s.l.), comprising sill-like reservoirs connected by small vertical structures, and a main reservoir at 2–3 km b.s.l. that is probably fluxed by magmatic volatiles. 2012 Elsevier Ltd. All rights reserved.
    Description: Published
    Description: 380-394
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: gas geochemistry, isotopes, degassing, modelling ; 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::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 57
    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
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 58
    Publication Date: 2017-04-04
    Description: Cuticle micromorphology together with epidermal and epistomatal wax, in both current- and first-year-old needles of conifer Pinus halepensis (Aleppo pine) trees growing under volcanic gas fumigation was analysed in Pisciarelli area, Campi Flegrei, Southern Italy. As a control, current- and first-year-old needles growing far from volcanic gas emission were also sampled. Using a multidisciplinary approach with SEM, TEM and X-ray, volcanic gases were shown to cause degradation on epicuticular and epistomatal waxes. Significant statistical variations of ultrastructural components of the cuticle, with 30 measurements, including total thickness of the cuticle, and details and proportions of all different layers, and use of confidence interval, revealed a high degree of sensitivity of Aleppo pine to this extreme environment. In the present study, non-significant thickness variations of the cell wall plus cuticle among current- and first-year-old needles of both fumigated and non fumigated trees have been found. However, at the ultrastructural level, significant variations in cell wall and total cuticle thickness, especially within the three zones of B1 fibrillar layer, revealed different equilibria for each of the four types of material. Using energy dispersive X-ray microanalysis, no sulphur was found in either cuticle or epidermal cells, but the presence of H2S in the fumarole gas is suspected to cause indirect and/or direct cuticle alterations of wax structure. Ultrastructural characters of plant cuticles related to emission of volcanic gases during the geological past are also discussed. Among these considerations, an identification key enabling distinction between non fumigated and fumigated materials with 9 characters, provides a good tool detecting the influence of volcanism for extant and fossil plants.
    Description: Published
    Description: 1–17
    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: restricted
    Keywords: Campi Flegrei ; Volcanic gases ; Pinus halepensis ; Hydrogen sulphide (H2S) ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 59
    Publication Date: 2017-04-04
    Description: The chemistry of Yellowstone fumarole gases shows the existence of two component waters, type MC, influenced by the addition of deep mantle fluid, and type CC, influenced by crustal interactions (CC). MC is high in 3He/4He (22 Ra) and low in 4He/40Ar ( 1), reflecting input of deep mantle components. The other water is characterized by 4He concentrations 3–4 orders of magnitude higher than air-saturated meteoric water (ASW). These high He concentrations originate through circulation in Pleistocene volcanic rocks, as well as outgassing of Tertiary and older (including Archean) basement, some of which could be particularly rich in uranium, a major 4He source. Consideration of CO2–CH4–CO–H2O–H2 gas equilibrium reactions indicates equilibration temperatures from 170 C to 310 C. The estimated temperatures highly correlate with noble-gas variations, suggesting that the two waters differ in temperature. Type CC is 170 C whereas the MC is hotter, at 340 C. This result is similar to models proposed by previous studies of thermal water chemistry. However, instead of mixing the deep hot component simply with cold, meteoric waters we argue that addition of a 4He-rich component, equilibrated at temperatures around 170 C, is necessary to explain the range in fumarole gas chemistry.
    Description: Published
    Description: 265–278
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: restricted
    Keywords: hydrothermal fluids ; Yellowstone Plateau ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 60
    Publication Date: 2021-09-03
    Description: Gas hazard was evaluated in the three most important cold gas emission zones on the flanks of the quiescent Colli Albani volcano. These zones are located above structural highs of the buried carbonate basement which represents the main regional aquifer and the main reservoir for gas rising from depth. All extensional faults affecting the limestone reservoir represent leaking pathways along which gas rises to the surface and locally accumulates in shallow permeable horizons forming pressurized pockets that may produce gas blowout when reached by wells. The gas, mainly composed by CO2 (〉90 vol.%), contains appreciable quantities of H2S (0.35-6 vol.%), and both represent a potentially high local hazard. Both gases are denser than air and accumulate near ground where they may reach hazardous concentrations, and actually lethal accidents frequently occur to animals watering at local ponds. In order to evaluate the rate of degassing and the related hazard, CO2 and H2S diffuse soil flux surveys have been repeatedly carried out by accumulation chamber. The viscous gas flux of some important discrete emissions has been also evaluated and the CO2 and H2S air concentration measured by portable devises and by Tunable Diode Laser profiles. The minimum potential lethal concentration of the two gases (250 ppm for H2S and 8 vol.% for CO2) is 320 times higher for CO2, whereas the CO2/H2S concentration ratio in the emitted natural gas is significantly lower (15-159). This explains why H2S reaches hazardous, even lethal, concentrations more frequently than CO2. A relevant hazard exists for both gases in the depressed zones (channels, excavations) particularly in the non-windy early hours of the day.
    Description: Published
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: partially_open
    Keywords: gas hazard ; hydrogen sulfide ; carbon dioxide ; Colli Albani volcano ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 61
    Publication Date: 2017-04-04
    Description: Historical earthquakes of the Gargano Promontory, an uplifted foreland sector in southeastern Italy, have been usually regarded as generated by inland faults. Some have been associated with activity of the Mattinata Fault, a section of a regional E-W shear zone. The 10 August 1893, Mw 5.4 is one of such earthquakes, but its current onshore location is only loosely based on the damage pattern. Regions that were hit by offshore earthquakes are also known to be affected by a methodological bias such that offshore historical events appear to be located onshore. To test this condition for the 1893 earthquake we pursued an alternative hypothesis for its location. The earthquake occurred near the Gondola Fault Zone, a right-lateral active fault system representing the offshore counterpart of the Mattinata Fault and hence capable of producing sizable earthquakes along the Gargano coast. We focused on its westernmost segment, suggesting that it could be the causative fault of the 1893 earthquake, in agreement with both the damage distribution and reported environmental effects. The approach we present works side by side with the recent developments of the algorithms used to compile historical catalogues, providing a fine-scale, geologically-based method to define or confirm the dubious location of historical earthquakes. Marine Paleoseismology is a new field stemming from the increased capabilities of high-resolution marine techniques in supporting classical paleoseismological analyses for the exploration of the seismogenic potential of offshore faults. Based on Late Pleistocene and Holocene individual or cumulative earthquake records, the potential of offshore faults can now be constrained in terms of expected magnitude and recurrence intervals. We stress the importance of revisiting historical earthquakes in coastal zones using marine paleoseismological data to assess regional seismic hazard, particularly in tectonic settings where regional-size seismogenic areas straddle the onshore and the offshore.
    Description: UF was financially supported by MIUR (Italian Ministry of Education and Research) FIRB Project “AIRPLANE”. This research has also benefited from funding provided by the Italian Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile (DPC). Scientific papers funded by DPC do not represent its official opinion and policies. This is ISMAR-Bologna contribution n. 1720.
    Description: Published
    Description: 1-17
    Description: 3.2. Tettonica attiva
    Description: 5.1. TTC - Banche dati e metodi macrosismici
    Description: JCR Journal
    Description: restricted
    Keywords: Adriatic foreland ; Gondola Fault Zone ; macroseismic intensity ; seismic hazard ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 62
    Publication Date: 2017-04-04
    Description: We reply to a comment by Messina et al., who strongly criticized our paper on the San Pio Fault, by showing that in areas of complex geology such as the central Apennines, where the current tectonic setting results from the superposition of different tectonic regimes, the equation: “most visible active fault = major seismogenic fault” can be misleading.
    Description: Published
    Description: 421-423
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Seismotectonics ; morphotectonics ; active fault ; San Pio basin ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 63
    Publication Date: 2017-04-04
    Description: A properly organized seismic network is a valuable tool for monitoring seismic zones and assessing seismic hazards. In this paper we propose a new method (seismic network evaluation through simulation, SNES) to evaluate the performance of hypocenter location of a seismic network. The SNES method gives, as a function of magnitude, hypocentral depth, and confidence level, the spatial distribution of the number of active stations in the location procedure and their relative azimuthal gaps, along with confidence intervals in hypocentral parameters. The application of the SNES method also permits evaluation of the magnitude of completeness (MC), the background noise levels at the stations, and assessment of the appropriateness of the velocity model used in location routine. Italy sits on a tectonically active plate boundary at the convergence of the Eurasian and African lithospheric plates and has a high level of seismicity. In this paper, we apply the SNES method to the Italian National Seismic Network (Rete Sismica Nazionale Centralizzata dell’Istituto Nazionale di Geofisica e Vulcanologia, RSNC– INGV) which has monitored Italian seismicity since the early 1980s, following the destructive 1980 Irpinia earthquake. In recent years, the RSNC–INGV has grown significantly. In fact, in February 2010, it received signals from 305 seismic stations, 258 with wideband three-component sensors. We constructed SNES maps for magnitudes of 1.5, 2, 2.5, and 3, fixing the hypocentral depth at 10 km and the confidence level at 95%. Through the application of the SNES method, we show that the RSNC–INGV provides the best monitoring coverage in the Apennine Mountains with errors that for M 2, are less than 2 and 4 km for epicenter and hypocentral depth, respectively. At M 2.5 this seismic network is capable of constraining earthquake hypocenters to depths of about 150 km for most of the Italian Peninsula. This seismic network provides a threshold of completeness down to M 2 for almost the entire Italian territory.
    Description: Published
    Description: 1213-1232
    Description: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Description: JCR Journal
    Description: reserved
    Keywords: Italian National Seismic Network ; Magnitude of Completeness ; Location Performance ; Seismic Noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 64
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    Seismological Society of America
    Publication Date: 2017-04-04
    Description: Calculating seismic hazard usually requires input that includes seismicity associated with known faults, historical earthquake catalogs, geodesy, and models of ground shaking. This paper will address the input generally derived from geologic studies that augment the short historical catalog to predict ground shaking at time scales of tens, hundreds, or thousands of years (e.g., SSHAC 1997). A seismogenic source model, terminology we adopt here for a fault source model, includes explicit three-dimensional faults deemed capable of generating ground motions of engineering significance within a specified time frame of interest. In tectonically active regions of the world, such as near plate boundaries, multiple seismic cycles span a few hundred to a few thousand years. In contrast, in less active regions hundreds of kilometers from the nearest plate boundary, seismic cycles generally are thousands to tens of thousands of years long. Therefore, one should include sources having both longer recurrence intervals and possibly older times of most recent rupture in less active regions of the world rather than restricting the model to include only Holocene faults (i.e., those with evidence of large-magnitude earthquakes in the past 11,500 years) as is the practice in tectonically active regions with high deformation rates. During the past 15 years, our institutions independently developed databases to characterize seismogenic sources based on geologic data at a national scale. Our goal here is to compare the content of these two publicly available seismogenic source models compiled for the primary purpose of supporting seismic hazard calculations by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the U.S. Geological Survey (USGS); hereinafter we refer to the two seismogenic source models as INGV and USGS, respectively. This comparison is timely because new initiatives are emerging to characterize seismogenic sources at the continental scale (e.g., SHARE in the Euro- Mediterranean, http://www.share-eu.org/; EMME in the Middle East, http://www.emmegem. org/) and global scale (e.g., GEM, http://www.globalquakemodel.org/; Anonymous 2008). To some extent, each of these efforts is still trying to resolve the level of optimal detail required for this type of compilation. The comparison we provide defines a common standard for consideration by the international community for future regional and global seismogenic source models by identifying the necessary parameters that capture the essence of geological fault data in order to characterize seismogenic sources. In addition, we inform potential users of differences in our usage of common geological/seismological terms to avoid inappropriate use of the data in our models and provide guidance to convert the data from one model to the other (for detailed instructions, see the electronic supplement to this article). Applying our recommendations will permit probabilistic seismic hazard assessment codes to run seamlessly using either seismogenic source input. The USGS and INGV database schema compare well at a first-level inspection. Both databases contain a set of fields representing generalized fault three-dimensional geometry and additional fields that capture the essence of past earthquake occurrences. Nevertheless, there are important differences. When we further analyze supposedly comparable fields, many are defined differently. These differences would cause anomalous results in hazard prediction if one assumes the values are similarly defined. The data, however, can be made fully compatible using simple transformations.
    Description: USGS Senior Scientist In Residence
    Description: Published
    Description: 519-525
    Description: 3.2. Tettonica attiva
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: open
    Keywords: Active fault ; fault source ; database ; seismic hazard ; Italy ; USA ; 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::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
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  • 65
    Publication Date: 2017-04-03
    Description: After an earthquake, rapid, real-time assessment of hazards such as ground shaking and tsunami potential is important for early warning and emergency response. Tsunami potential depends on sea floor displacement, which is related to the length, L, width, W, mean slip, D, and depth, z, of earthquake rupture. Currently, the primary discriminant for tsunami potential is the centroid-moment tensor magnitude, MwCMT, representing the seismic potency LWD, and estimated through an indirect, inversion procedure. The obtained MwCMT and the implied LWD value vary with the depth of faulting, assumed earth model and other factors, and is only available 30 min or more after an earthquake. The use of more direct procedures for hazard assessment, when available, could avoid these problems and aid in effective early warning. Here we present a direct procedure for rapid assessment of earthquake tsunami potential using two, simple measures on P-wave seismograms – the dominant period on the velocity records, Td, and the likelihood that the high-frequency, apparent rupture-duration, T0, exceeds 50-55 sec. T0 can be related to the critical parameters L and z, while Td may be related to W, D or z. For a set of recent, large earthquakes, we show that the period-duration product TdT0 gives more information on tsunami impact and size than MwCMT and other currently used discriminants. All discriminants have difficulty in assessing the tsunami potential for oceanic strike-slip and back-arc or upper-plate, intraplate earthquake types. Our analysis and results suggest that tsunami potential is not directly related to the potency LWD from the “seismic” faulting model, as is assumed with the use of the MwCMT discriminant. Instead, knowledge of rupture length, L, and depth, z, alone can constrain well the tsunami potential of an earthquake, with explicit determination of fault width, W, and slip, D, being of secondary importance. With available real-time seismogram data, rapid calculation of the direct, period- duration discriminant can be completed within 6-10 min after an earthquake occurs and thus can aid in effective and reliable tsunami early warning.
    Description: In press
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: Earthquake dynamics ; Earthquake source observations ; Seismic monitoring ; Body waves ; Early warning ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 66
    Publication Date: 2017-04-04
    Description: The elevation of the Capo Vaticano coastal terraces (Tyrrhenian coast, central Calabria) is the combination of regional uplift and repeated coseismic displacement. We subtract the regional uplift from the total uplift (maximum average uplift rates 0.81-0.97 mm/yr since ~0.7 Ma) and obtain a residual fault-related displacement. Then, we model the residual displacement to provide constraints to the location and geometry of the seismogenic source of the 1905 M7 earthquake, the strongest – and still poorly understood – earthquake of the instrumental era in this area. We test four different potential sources for the dislocation modelling and find that 1) three sources are not compatible with the displacement observed along the terraces, and 2) the only source consistent with the local deformation is the 100°-striking Coccorino Fault. We calculate average long-term vertical slip rates of 0.2-0.3 mm/yr on the Coccorino Fault and estimate an average recurrence time of ~one millennium for a 1905-type earthquake
    Description: Published
    Description: 378-389
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: marine terrace ; fault ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 67
    Publication Date: 2017-04-04
    Description: In April 1998, a swarm of 1800 microearthquakes near the village of Iznajar (southern Spain) was recorded at the Granada basin short-period seismic network. Focal mechanisms from local P-wave polarities are poorly constrained and cannot characterize the seismotectonics of the series. Here we combine polarity information and multiplet relocation to address this issue. We use waveform cross correlation on P and S arrivals to identify events with highly similar seismograms, group our detections into multiplet clusters, and invert the cross-correlation time delays to obtain precise relative locations. Relative locations have errors of several tens to a few hundreds of meters horizontally and vertically, and define strike and dip of active fault patches with an accuracy of 20°–30°. We introduce the multiplet fault plane orientations into focal mechanism inversion, now yielding mostly well-constrained solutions, in addition to resolving the nodal plane symmetry. We observe mainly north-south left-lateral strike-slip faulting and a few north-northwest–south-southeast normal faulting solutions, illustrating the kinematic complexity of the swarm, and pointing to a local deformation style different from the nearby Granada basin.
    Description: Published
    Description: 3421-3429
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Fault plane solution ; Precise location ; Seismic swarm ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 68
    Publication Date: 2017-04-04
    Description: Rapid extension and active normal faulting in the western extremity of the Corinth Gulf are accompanied by fast coastal uplift.We investigate Pleistocene uplift west of Aigion, by attempting to date remains of marine terraces and sedimentary sequences by calcareous nannoplankton and U-series analyses. Net uplift initiated recently, due to abandonment of an older rift-bounding fault zone and increase in activity on the presently active, coastal fault zone. This change apparently coincides with an abrupt slow down (or, termination) of secondary fault block tilting within the broader hangingwall block of the older zone, indicated by an angular unconformity that dates in the early part ofMIS10 ( 390–350 ka BP, preferably, in the earlier part of this period). Net uplift driven by the coastal zone resulted in the formation of MIS9c (330 ka) and younger terraces. The formation of the unconformity and the initiation of net uplift coincide temporally with a 300–400 ka unconformity recognized by recent studies in a wide area offshore Aigion i.e. they could be part of an evolutionary event that affected the entirewestern part of the Corinth Rift or, a large area therein. Uplift rate estimates at four locations are discussed with reference to the morphotectonic context of differential uplift of secondary fault blocks, and the context of possible increase in uplift ratewith time. Themost reliable and most useful estimate for uplift rate at the longitude of the studied transect is 1.74–1.85mm/year (time-averaged estimate for the last 240 ka, based on calcareous nannoplankton and sequence-stratigraphic interpretation)
    Description: ‘3HAZ Corinth’ E.U. research project 004043 (GOCE)-3HAZ-Corinth
    Description: Published
    Description: 78 - 104
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: partially_open
    Keywords: coastal uplift ; marine terraces ; marine sequences ; deformation rate ; Pleistocene ; Corinth Gulf Reef ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 69
    Publication Date: 2017-04-04
    Description: Horizontal-to-vertical spectral ratios using ambient noise (HVNSR) are commonly used in site effects studies. In the practice, many operators assume stability over time of HVNSR and base their analyses on few very short time windows. The availability of a long period of continuous microtremor recording allowed us to analyze three months of data coming from a dense array experiment performed at Cavola, a village in northern Apennines. This condition offers a good opportunity to check the validity of the stability assumption and to investigate variations of the local ambient noise wave-field composition. The Cavola site is characterized by landslide sediments over stiffer materials with a moderate impedance contrast and by a complex morphology. An intense industrial activity in the village contributes to the generation of seismic noise. After identifying this noise source in the time series, we evaluate its effects on HVNSR. The results indicate that the spectral peak of HVNSR varies in amplitude and frequency, posing a warning about stability in time. Analyzing the spectra we identify the anthropic activity as responsible for changes in the composition of the noise wave field. These variations affect HVNSR, including peak frequency and also ground-motion polarization.
    Description: Published
    Description: 1263-1275
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: noise measurements ; Rayleigh waves ; polarization ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 70
    Publication Date: 2017-04-04
    Description: IEEE Standard for Local and Metropolitan Area Networks (hereafter IEEE 802.16; online at http://standards.ieee.org/getieee802/802.16.html) is one of the most promising mobile and fixed broadband wireless access technologies for next-generation all-IP networks in the 3.5 GHz band (European spectrum profile). Commonly known as Universal WiMAX (worldwide inter-operability for microwave access), this access technology reaches a high bit rate and covers large areas with a single base station, making it possible to offer connectivity to end users in a cost-effective way. A further useful property of the WiMAX technology is that the transmission can be used both in line-of-sight (LOS) and non-line-of-sight (NLOS) environments, allowing highly feasible communications (WiMAX Forum 2004). Thanks to these features, IEEE 802.16 opens the way to the use of wireless technologies in the environmental monitoring of areas such as seismic and volcanic zones.
    Description: European Community’s Sixth Framework Programme, Contract no. IST-034622-IP
    Description: Published
    Description: 411-419
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: WiMAX ; volcano monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 71
    Publication Date: 2022-06-14
    Description: On 6 April 2009, at 01:32 GMT, an Mw 6.3 seismic event hit the central Apennines, severely damaging the town of L’Aquila and dozens of neighboring villages and resulting in approximately 300 casualties (Istituto Nazionale di Geofisica e Vulcanologia, http://www.ingv.it; MedNet, http://mednet.rm.ingv.it/proce- dure/events/QRCMT/090406_013322/qrcmt.html). This earth- quake was the strongest in central Italy since the devastating 1915 Fucino event (Mw 7.0). The INGV national seismic net- work located the hypocenter 5 km southwest of L’Aquila, 8–9 km deep. Based on this information and on the seismotectonic framework of the region, earthquake geologists traveled to the field to identify possible surface faulting (Emergeo Working Group 2009a, 2009b). The most convincing evidence of pri- mary surface rupture is along the Paganica fault, the geometry of which is consistent with seismological, synthetic aperture radar (SAR) and GPS data. Investigation of other known nor- mal faults of the area, i.e., the Mt. Pettino, Mt. San Franco, and Mt. Stabiata normal faults suggested that these structures were not activated during the April 6 shock (Emergeo Working Group 2009a, 2009b). In this report, we first describe the seismotectonic frame- work of the area, and then we present the field information that supports the occurrence of surficial displacement on the Paganica fault.
    Description: Published
    Description: 940-950
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Surface coseismic ruptures ; Paganica Fault ; earthquake ; 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::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 72
    Publication Date: 2017-04-04
    Description: Managua, capital of Nicaragua, is built on the shore of Lake Managua, within a densely faulted graben at a major discontinuity in the Central American volcanic chain. Shallow moderate earthquakes (Ms 6–6.2) ruptured faults with devastating effect at the heart of urban Managua in 1931 and 1972, and damaging earthquakes are cataloged in the earlier history of the surrounding region. The Aeropuerto fault is a major structure in the Managua Graben, but like other faults in this area its behavior is little understood. Paleoseismic investigations now suggest that the most recent large earthquake on this fault occurred sometime during the interval A.D. 1650–1810. An earlier earthquake on this fault occurred prior to A.D. 1390 and possibly around 2000 B.P. On the basis of stratigraphic correlations we estimate the ages of two shorelines associated with former high stands of Lake Managua to be less than 6.4 ka and approximately 2 ka, respectively. Deformation of these abandoned shorelines adjacent to the Aeropuerto fault implies a vertical slip rate of 0.3 to 0.9 mm/yr. Strikeslip movement on this fault is also expected, but no direct measurement could be performed. By comparison with faults of similar geometry in the Managua area that ruptured in 1931 and 1972, we suspect a left-lateral component of horizontal slip that is higher than the vertical one but less than 5 mm/yr. Additional data on slip rate and timing of paleoearthquakes are needed to better assess the Holocene behavior of the Managua faults and to investigate the influence of magmatic processes on the nature of faulting in the Managua Graben.
    Description: Published
    Description: 1694-1707
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: palaeoseismology ; Aeropuerto Fault ; Managua, Nicaragua ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 73
    Publication Date: 2017-04-04
    Description: In this note, we investigate the characteristics of ambient noise cross-correlations for station pairs in northern Italy, considering the secondary microseism bandwidth (0.1-0.6 Hz). The preliminary analysis that we performed exploiting the available continuous recording in the investigated area, agrees with the recent results of Pedersen et al. (2007): the directionality of the noise signal cannot be disregarded when the group velocity is estimated in the range 0.1-0.6 Hz and the selection of the path orientation for tomography must be carefully performed. In particular, while the favourable directions with respect to microseisms generated along the Atlantic coasts of France, Norway and British Islands cover a quite wide azimuthal range (from about 270N to 5N), allowing us to reliably estimate the fundamental mode Rayleigh group velocity for paths in the Alps (about 2.7 km/s), more care must be taken when the microseisms are generated in the Mediterranean Sea. In that case, different locations of the generating areas of microseisms could provide biased estimates of the group velocity due to differences between the true and the apparent velocity of propagation between the stations.
    Description: Published
    Description: 1389-1398
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: microseisms ; ambient noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 74
    Publication Date: 2017-04-04
    Description: The Campi Flegrei (southern Italy) is one of the most active calderas in the world. This caldera is characterized by episodes of slow vertical ground movement, called bradyseism. With several hundred thousand people living within its borders, this area is in a high-risk category should there be an eruption. The seismological monitoring system in the Campi Flegrei is based on nine seismic stations, eight of which are equipped with short-period seismometers (1 Hz), and one with a broadband seismometer (60 sec–50 Hz). While all of the seismic stations are located on land, part of the seismic activity occurs in the undersea area of the Pozzuoli Gulf (Campi Flegrei), where there are no seismic stations. This gap in the data coverage produces a biased and incomplete image of the volcanic area.We carried out an experiment in the Pozzuoli Gulf with the installation of two broadband seismic stations on the seafloor with remote and continuous data acquisition for a duration of 31 days between January and March 2005. Using the data acquired, we have computed the power spectral density (PSD) to characterize the background seismic noise, and to evaluate the true noise variation, we have generated the seismic noise probability density functions from the computed PSD curves. The results of our analysis show that the broadband seismic noise is high when compared with the Peterson noise model (land model), but for periods less than 0.3 sec, the seismic noise on the seafloor is lower than the recordings on land over the same period range. The last bradyseismic crisis (1982–1984) highlights the importance of this frequency range, where most of the spectral content of the recorded earthquakes was observed. Finally, we evaluate the detection threshold of a new seismic station located on the seafloor of the Campi Flegrei caldera considering the characteristics of the local seismicity. This analysis shows that the detection threshold for the sea-floor stations (Mw ∼ 0:2) is less than that for land stations (Mw ∼ 0:8).
    Description: Published
    Description: 2962–2974
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei Caldera ; Sea-Floor and On-Land Seismic ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 75
    Publication Date: 2017-04-04
    Description: This article presents the results of new field and aerial photo surveys of the Atalanti fault and of the mesoseismal area of the 20 and 27 April 1894 earthquakes. Coupled with a reanalysis of contemporary reports and previous investigations, these are used to gain a better understanding of the faults responsible for these events and their seismic behavior. The first shock was smaller and probably located inshore or offshore the Malessina peninsula. No resolving field evidence has been found to locate the seismogenic structure responsible for this shock. On the basis of the limited information available, we suggest the Malessina escarpment, a 12-km-long, ENE-trending, NW-dipping fault as a possible structure responsible for this event. On the other hand, the second and largest shock is definitely related to the Atalanti fault sensu stricto, a main WNW-trending, N-dipping active fault extending between the Platirema valley (a few km NW of the town of Atalanti) and Larymna. The total length of the rupture recognized in the field is about 32 km, but it can be extended further SE up to 40 km. No evidence for a longer rupture extending some other 20 km to the NW, between the Karagiozis river and Ag. Kostantinos, is found. The complex geometry of the fault with bends and step overs appears to be controlled by preexisting transverse structures. Minimum coseismic vertical throws, measured in the field after more than a century elapsed from the earthquake, are 30–80 cm, thus consistent with contemporary reports indicating 1-m average. Slip rates are not well constrained. The available estimates fall in the range 0.1–0.5 mm/yr confirming the smaller amount of crustal extension taking place in this area with respect to other nearby regions such as the Corinth gulf. No new data are available to define the average recurrence interval typical of the Atalanti fault. However, a reconsideration of the existing information induced us to rule out the possibility that the famous 426 B.C. earthquake occurred on the Atalanti fault. On the basis of the extent and size of the rupture recognized in the field, a M 6.8 is estimated for the second and largest shock.
    Description: Published
    Description: 760-780
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Surface rupture ; 1894 Atalanti Earthquake ; Greece ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 76
    Publication Date: 2017-04-04
    Description: The Atalanti fault bounds to the southwest the Evoikos Gulf, one of the major extensional basins of central Greece. This fault ruptured during the 1894 earthquakes, producing at the surface a complex, ca. 30-km-long rupture. Paleoseismological trenching performed at three sites along this fault provided the first insights on its seismogenic behavior. Unfavorable trench stratigraphy and scarcity of datable material made the identification and characterization of individual paleoearthquakes quite difficult. However, by integrating paleoseismological, geological, historical, and archaeoseismological data, we defined three surface-faulting earthquakes. The most recent event is the 1894 earthquake; the penultimate occurred during the Middle Ages between A.D. 770 and 1160, whereas the third event back occurred in Roman times between 50 B.C. and A.D. 230 and is interpreted to be the Opus earthquake of A.D. 105. These results suggest that 1894-type earthquakes repeat each 660–1120 yr. The average minimum slip per event and vertical slip rates are of the order of 45 cm and 0.4–1.6 mm/yr, respectively. These values are in agreement with other geological estimates and with geodetic measurements. Because of the short time elapsed since the 1894 earthquake, the Atalanti fault does not appear to contain an important seismogenic potential. On the other hand, these results may shed light on the potential of other seismogenic sources threatening the area.
    Description: Published
    Description: 531-549
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: palaeoseismology ; 1894 Atalanti Earthquake ; Greece ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 77
    Publication Date: 2017-04-04
    Description: On 16 December 1857, a strong earthquake (M ∼7) struck a large portion of the southern Apennines about 150 km southeast of Naples. The earthquake was thoroughly investigated by Irish engineer Robert Mallet, who wrote an extensive report that is still regarded as a landmark in observational seismology. Because of the concentration of damage in the High Agri valley, and contrary to Mallet’s own findings, for many years the earthquake was referred to as the “Val d’Agri earthquake” and was believed by most investigators to have ruptured the 20–25-km normal fault lying beneath this intermontane basin. The magnitude of the earthquake, however, and evidence for earthquake complexity suggest that the true rupture length has been so far underestimated. We contend that the 1857 earthquake ruptured in a cascade fashion two adjacent and relatively well-known faults: first the smaller Melandro–Pergola fault, commonly believed to represent a seismic gap between the causative faults of the 1857 and of the 1980 Irpinia (Mw 6:9) earthquakes; and then the larger Agri valley fault proper. Contemporary chronicles reported a time lapse of 2–3 min between the two ruptures, thus effectively making them two independent shocks. The rupture must have proceeded unilaterally from the northwestern edge of the Melandro–Pergola fault, where Mallet placed the earthquake epicenter, thus explaining the concentration of damage—and attention by rescue crews and subsequent investigators—in the southeastern portion of the High Agri valley.
    Description: This work was funded by the project Assessing the Seismogenic Potential and the Probability of Strong Earthquakes in Italy, funded by the Italian Civil Defense Department within the 2004–2006 agreement with the Istituto Nazionale di Geofisica e Vulcanologia grant to P. Burrato.
    Description: Published
    Description: 139-148
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: partially_open
    Keywords: 1857 Basilicata earthquake ; southern Italy ; Val d'Agri ; seismic gap ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 78
    Publication Date: 2022-06-08
    Description: Paleoseismic studies of two historically aseismic Quaternary faults in Australia confirm that cratonic faults in stable continental regions (SCR) typically have a long-term behavior characterized by episodes of activity separated by quiescent intervals of at least 10,000 and commonly 100,000 years or more. Studies of the approximately 30-km-long Roopena fault in South Australia and the approximately 30-km-long Hyden fault in Western Australia document multiple Quaternary surface-faulting events that are unevenly spaced in time. The episodic clustering of events on cratonic SCR faults may be related to temporal fluctuations of fault-zone fluid pore pressures in a volume of strained crust. The long-term slip rate on cratonic SCR faults is extremely low, so the geomorphic expression of many cratonic SCR faults is subtle, and scarps may be difficult to detect because they are poorly preserved. Both the Roopena and Hyden faults are in areas of limited or no significant seismicity; these and other faults that we have studied indicate that many potentially hazardous SCR faults cannot be recognized solely on the basis of instrumental data or historical earthquakes. Although cratonic SCR faults may appear to be nonhazardous because they have been historically aseismic, those that are favorably oriented for movement in the current stress field can and have produced unexpected damaging earthquakes. Paleoseismic studies of modern and prehistoric SCR faulting events provide the basis for understanding of the long-term behavior of these faults and ultimately contribute to better seismic-hazard assessments.
    Description: Published
    Description: 1913-1934
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: palaeoseismology ; Australia ; fault behavior ; stable continental regions ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 79
    Publication Date: 2017-04-04
    Description: This study contributes paleoseismological data on the recent history of surface-rupturing earthquakes on the southern (main) branch of the North Anatolian fault zone (NAFZ, Turkey), west of the Bolu basin. We focused on the fault segment that ruptured during the 1967 Mudurnu Valley earthquake (Ms 7.1), which preceded the devastating earthquakes of 1999 in the sequence of westward-migrating NAFZ earthquakes since 1939. Geomorphological mapping was carried out in a search for trenching sites on the central part of the 22 July 1967 earthquake segment. In the absence of locations in sedimentary environments best suited for paleoseismological interpretation of faulted Holocene deposits, we trenched fluvial channel deposits at a terrace of the graveldominated Mudurnu River. The most conservative interpretation of the trench stratigraphy and faulting evidence suggests that at least one paleoearthquake (most probably two) occurred after A.D. 1693. The 1967 earthquake segment has ruptured at least once since the historical earthquake of A.D. 1668, which was previously considered to be a likely candidate for the penultimate event, and before 1967. It is not possible to confidently assign the penultimate event to one of the post A.D. 1693 historical earthquakes in the broader area around the Mudurnu Valley (e.g., the earthquake of A.D. 1719) because the historical data published so far do not provide conclusive information about when past ruptures of the Mudurnu Valley branch of the NAFZ (a secluded area) did or did not take place.
    Description: European Community project RELIEF
    Description: Published
    Description: 1646-1661
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: partially_open
    Keywords: Paleoseismicity ; Turkey ; North Anatolian Fault ; 1967 earthquake ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 80
    Publication Date: 2017-04-04
    Description: The new Italian National Seismic Network (INSN) is a dense network of broadband stations deployed for monitoring Italian seismicity. The network consists of 250 stations with a typical station spacing of !40 km. Earthquake early warning is the rapid detection of an event in progress, assessment of the hazard it poses, and transmission of a warning ahead of any significant ground motion. We explore the potential for using the INSN real-time network for the purpose of earthquake early warning. We run the ElarmS early warning methodology off-line using a data set of more than 200 events with magnitudes between 2.5 and 6.0. A scaling relation for magnitude determination from the dominant period of the first seconds of signal following the P onset is developed from the data set. The standard deviation in the magnitude estimates using this approach is 0.4 magnitude units, and all event magnitude estimates are within !0:75 magnitude units of the true magnitude. Given the existing distribution of seismic stations it takes an average of 10 sec after event initiation before the P wave has been detected at four stations. If we require a detection at four stations before issuing the first alert, then the blind zone, within which no warning would be available, has a radius of !37 km. The ElarmS methodology can provide a warning earlier than this but with a greater uncertainty. An assessment of past damaging earthquakes across Italy shows that applying ElarmS with the existing seismic network could provide warning to population centers in repeats of past events. For example, in a repeat of the 1980 Irpinia earthquake Naples could receive an !15- sec warning. The variations in the size of the blind zone and warning times for different regions can be used as a guide to selecting strategic locations for future station deployments.
    Description: Published
    Description: 495-503
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Early Warning ; Earthquake Location ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 81
    Publication Date: 2017-04-04
    Description: With the aim to find a more objective way to detect seismic families, we applied a series of successive steps to constrain the results of a waveform similarity analysis. The evaluation of similarity was carried out on the waveforms recorded in the period 1999–2003 by the stations operating in the Garfagnana area, located in northern Tuscany (Italy). The algorithm is based on the cross-correlation technique applied in a process that overcomes the limit of one order of magnitude between events to be compared through a bridging technique. In practice, if two couples of events (A, B) and (B, C), each exceeding the correlation threshold, share a common quake (B), then all three events are attributed to the same family even if the match between A and C is below a value chosen as a reference for similarity. To avoid any subjective choice of threshold for cross-correlation values, the results from the computation algorithm are submitted to a routine that gives increasing reliability to them if they are confirmed by the three components of the seismogram and if the number of families detected by each station is confirmed by more recordings. This latter constraint is made possible by the geometry of the recording network, with interdistances between stations of the order of 40–50 km. The process finally leads to the recognition of 27 families detected and confirmed by, on average, 3 stations that represent 40% of the recording capabilities. Since the performances of the recording network have been very odd in the past, especially in the early years of operation, the reliability of the detection is much higher, as in most cases the stations that detected the families were the only ones to be effectively recording. The methodology proved to be more efficient than other methods applied in the past; moreover, the results could be probably improved even more if, instead of doing a one-run process, it would be borne as a trial-and-error approach.
    Description: Published
    Description: 1903-1915
    Description: JCR Journal
    Description: reserved
    Keywords: Seismicity ; multiplets ; seismic families ; seismic sequences ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 82
    Publication Date: 2017-04-04
    Description: A small aperture quadripartite seismic array was installed on the south-east flanks of Mt. Vesuvius about 1 km far from the crater axis, in order to improve the seismic monitoring of this active volcano. The array has the following main purposes: i) to discriminate natural-source generated signals by artificial-source-generated signals; ii) to detect and track the source of possible Long Period (LP) events; iii) to detect coherent phases in the low frequency noise that may be related to magma movements (tremor insurgence). In addition, the array greatly helps in locating the seismic signals produced by blasts (both in land and sea), allowing a fast discrimination of possible natural long period (LP) quakes. The array is also an useful tool for retrieving the kinematic properties of the wavefield associated to volcano-tectonic (VT) earthquakes (more than 99% of the whole natural seismicity) and to all the other transients which are routinely observed(landslides, artificial blasts). We also use the array to investigate if correlated signals are present in the background noise (insurgence of volcanic tremor). The main result obtained during this first year of observation is that one LP was clearly recognized in the background seismicity at Mt. Vesuvius.
    Description: Published
    Description: 344-355
    Description: open
    Keywords: Volcano monitoring ; Array techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 83
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    3
    In:  Computers and Geosciences, Münster, 3, vol. 28, no. 45, pp. 309-326, pp. L11609, (ISBN 0-471-26610-8)
    Publication Date: 2002
    Keywords: Inversion ; Data analysis / ~ processing ; Non-linear effects ; Discrimination ; C&G
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  • 84
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    Soc. Explorat. Geophys.
    In:  60th Annual Meeting of SEG, Cambridge, MA, USA, Soc. Explorat. Geophys., vol. 10, no. 18, pp. 1400-1403
    Publication Date: 1990
    Keywords: Inversion ; Waves ; AnisotropyS ; cracks and fractures (.NE. fracturing)
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  • 85
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    Soc. Explorat. Geophys.
    In:  60th Annual Meeting of SEG, Tsukuba, Soc. Explorat. Geophys., vol. C 560, 183 pp., no. No. 2207, pp. 1404-1406, (ISBN 3-933346-037)
    Publication Date: 1990
    Keywords: Inversion ; Polarization ; Shear waves ; Vertical seismic profiling ; Anisotropy
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  • 86
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    Soc. Explorat. Geophys.
    In:  60th Annual Meeting of SEG, San Francisco, Soc. Explorat. Geophys., vol. C 560, 183 pp., no. PL-TR-91-2130, pp. 1618-1621, (ISBN 3-933346-037)
    Publication Date: 1990
    Keywords: Stacking ; p-tau method ; Inversion
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  • 87
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    Soc. Explorat. Geophys.
    In:  57th Annual International of SEG, Univ. Minnesota, Minneapolis, Soc. Explorat. Geophys., vol. 10, no. 421, pp. 61-63, (ISBN 3-933346-037)
    Publication Date: 1987
    Keywords: Filter- ; Fourier transform ; Inversion ; Attenuation ; Quality factor
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  • 88
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    Soc. Explorat. Geophys.
    In:  Abstract SEG-Meeting, Atlanta, Soc. Explorat. Geophys., vol. 10, no. 47, pp. 197-200
    Publication Date: 1984
    Keywords: Inversion ; Conference abstr.
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  • 89
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    Soc. Explorat. Geophys.
    In:  Abstract SEG-Meeting, Las Vegas, Soc. Explorat. Geophys., vol. 10, no. GL-TR-89-0230, pp. 341-346, (ISBN 3-933346-037)
    Publication Date: 1983
    Keywords: Inversion ; Conference abstr.
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  • 90
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    Soc. Explorat. Geophys.
    In:  Abstract SEG-Meeting, Los Angeles, Soc. Explorat. Geophys., vol. 10, no. 41, pp. 19, (ISBN 3-933346-037)
    Publication Date: 1982
    Keywords: Inversion ; Conference abstr.
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  • 91
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    Soc. Explorat. Geophys.
    In:  Abstract, SEG-Meeting, Houston, Soc. Explorat. Geophys., vol. 339-350, no. 1722, pp. 344, (ISBN 3-933346-037)
    Publication Date: 1980
    Keywords: Inversion ; Conference abstr.
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  • 92
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    Soc. Explorat. Geophys.
    In:  47. Meeting of the SEG, Calgary, Alberta, Soc. Explorat. Geophys., vol. C 560, 183 pp., no. 51, pp. 193-210, (ISBN 3-933346-037)
    Publication Date: 1977
    Keywords: Inversion
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  • 93
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    Wiley
    In:  Mathematical Methods for Digital Computers, Volume 1, Sapporo, Japan, Wiley, vol. 17, no. 16, pp. 211-236, (ISBN 0080419208)
    Publication Date: 1967
    Keywords: Inversion
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  • 94
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    Wiley
    In:  Mathematische Methoden für Digitalrechner, Sapporo, Japan, Wiley, vol. 1, no. 16, pp. 106-126, (ISBN 0080419208)
    Publication Date: 1967
    Keywords: Inversion
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