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  • Articles  (11)
  • GPS  (6)
  • 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology  (5)
  • Elsevier  (9)
  • American Geophysical Union  (2)
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • Public Library of Science
  • 2005-2009  (11)
  • 2007  (11)
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  • Articles  (11)
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  • 2005-2009  (11)
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  • 1
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    An expanded non-Arrhenian model for silicate melt viscosity: A treatment for metaluminous, peraluminous and peralkaline liquids (2007)
    Elsevier
    Details
    Publication Date: 2020-10-29
    Description: We present new viscosity measurements for melts spanning a wide range of anhydrous compositions including: rhyolite, trachyte, moldavite, andesite, latite, pantellerite, basalt and basanite. Micropenetration and concentric cylinder viscometry measurements cover a viscosity range of 10−1 to 1012 Pas and a temperature range from 700 to 1650 °C. These new measurements, combined with other published data, provide a high-quality database comprising ∼800 experimental data on 44 well-characterized melt compositions. This database is used to recalibrate the model proposed by Giordano and Dingwell [Giordano, D., Dingwell, D. B., 2003a. Non-Arrhenian multicomponent melt viscosity: a model. Earth Planet. Sci. Lett. 208, 337–349] for predicting the viscosity of natural silicate melts. The present contribution clearly shows that: (1) the viscosity (η)–temperature relationship of natural silicate liquids is very well represented by the VFT equation [log η=A+B/ (T−C)] over the full range of viscosity considered here, (2) the use of a constant high-T limiting value of melt viscosity (e.g., A) is fully consistent with the experimental data, (3) there are 3 different compositional suites (peralkaline, metaluminous and peraluminous) that exhibit different patterns in viscosity, (4) the viscosity of metaluminous liquids is well described by a simple mathematical expression involving the compositional parameter (SM) but the compositional dependence of viscosity for peralkaline and peraluminous melts is not fully controlled by SM. For these extreme compositions we refitted the model using a temperature-dependent parameter based on the excess of alkalies relative to alumina (e.g., AE/SM). The recalibrated model reproduces the entire database to within 5% relative error (e.g., RMSE of 0.45 logunits).
    Description: Published
    Description: 42–56
    Description: reserved
    Keywords: Viscosity ; Model ; Silicate melts ; Metaluminous ; Peraluminous ; Peralkaline ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    The viscosity of shoshonitic melts (Vulcanello Peninsula, Aeolian Islands, Italy): insight on the magma ascent in dikes (2007)
    Elsevier
    Details
    Publication Date: 2021-01-14
    Description: The viscosity of shoshonitic melts from Vulcanello Peninsula (Vulcano Island, Italy) is experimentally determined at temperatures between 733 K and 1673 K. The water content of the melts varies from 0.03 to 4.75 wt% H2O. The micropenetration technique is employed at ambient pressure in the high viscosity range (109-1012 Pa·s). Falling sphere(s) experiments are performed at 500 and 2000 MPa in the low viscosity range (100.5-103 Pa·s). Results show a decrease of about 2 orders of magnitude in viscosity if ~ 3 wt% of water is added to the dry melt at 1300 K. At high temperature the viscosity of Vulcanello melts is intermediate between that of andesitic and basaltic melts. In contrast, at low temperatures (≤1050 K), the shoshonitic melt is characterized by a lower viscosity with respect to the two previous melts. Based on our new data set, a calculation model is proposed to predict the viscosity of the shoshonitic melts as a function of temperature and water content. The viscosity data are used to constrain the ascent velocity of shoshonitic magmas from Vulcanello within dikes. Using petrological data (temperature and crystal content of the magma) and volcanological information (geometrical parameters of the eruptive fissure and depth of magma storage), we estimate the time scale for the ascent of magma from the main reservoir to the surface. Results show time scales in the order of hours to few days. We conclude that the rapid ascent of poorly evolved melts from Moho depths should be taken into account for the hazard assessment of Vulcano Island.
    Description: Published
    Description: 89-102
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: open
    Keywords: dikes ; ascent velocity ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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    High-temperature viscosity measurements of hydrous albite liquid using in-situ falling sphere viscometry at 2.5 GPa (2007)
    Elsevier
    Details
    Publication Date: 2020-10-29
    Description: In-situ falling-sphere viscometry using shadow radiography in a multianvil apparatus was conducted on a series of samples along the NaAlSi3O8–H2O join up to 2.8 wt.% H2O at the Spring-8 synchrotron radiation facility (Hyogo, Japan). This allowed us to determine viscosities normally too low to be measured at ambient pressure for hydrous silicate melts at high temperatures due to rapid devolatilization. Pressure was fixed at 2.5 GPa for all experiments allowing us to gauge the effect of chemical composition on viscosity. In particular, the series of samples allowed us to vary the melt's degree of polymerization while maintaining a constant Al to Si ratio. Our results show that, for all samples, viscosity decreases as a function of pressure between 1 atm and 2.5 GPa at 1550 °C, indicating that the pressure anomaly can still be observed as depolymerization of the melt increases from nominally 0 (dry albite liquid) to NBO/T=0.8 (assuming water speciation entirely as hydroxyl groups at experimental conditions). We also find that the magnitude of the decrease in viscosity over this pressure interval does not appear to be dependent on the amount of water in the melt (i.e., NBO/T). An explanation for this behavior might be that the molar volume, at least over this limited compositional range, is nearly constant and the effects of compression of these melts, though different in degree of polymerization, are similar.
    Description: Published
    Description: 2-9
    Description: JCR Journal
    Description: reserved
    Keywords: Viscosity ; Silicate melts ; High pressure ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    The evolution of the Calabrian Arc: Evidence from paleomagnetic and GPS observations (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The present-day arcuate shape of the Calabrian Arc has been accomplished during Neogene and Early Pleistocene by large and opposite vertical axis rotations along the two arms of the Arc. Clockwise (CW) rotations have been systematically registered in Sicily and Calabria, whereas counterclockwise (CCW) rotations were measured in Southern Apennines. Such opposite vertical axis rotations ceased in the uppermost part of the Lower Pleistocene (about 1 Ma ago) along almost the entire Calabrian Arc and are not observed in the present-day GPS velocity field. The end of the Calabrian Arc bending during the Quaternary marks a decrease in the efficiency of the tectonic processes related to the long-lived subduction of the Ionian slab, which caused the halting of the back-arc opening in the Southern Tyrrhenian Sea.
    Description: Published
    Description: 259-274
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Calabrian Arc ; subduction ; paleomagnetism ; GPS ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    Viscosity and glass transition temperature of hydrous float glass (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Viscosity of water-bearing float glass (0.03–4.87 wt% H2O) was measured in the temperature range of 573–1523 K and pressure range of 50–500 MPa using a parallel plate viscometer in the high viscosity range and the falling sphere method in the low viscosity range. Melt viscosity depends strongly on temperature and water content, but pressure up to 500 MPa has only minor influence. Consistent with previous studies on aluminosilicate compositions we found that the effect of dissolved water is most pronounced at low water content, but it is still noticeable at high water content. A new model for the calculation of the viscosities as a function of temperature and water content is proposed which describes the experimental data with a standard deviation of 0.22 log units. The depression of the glass transition temperature Tg by dissolved water agrees reasonably well with the prediction by the model of Deubener [J. Deubener, R. Müller, H. Behrens, G. Heide, J. Non-Cryst. Solids 330 (2003) 268]. Using water speciation measured by near-infrared spectroscopy we infer that although the effect of OH groups in reducing Tg is larger than that of H2O molecules, the difference in the contribution of both species is smaller than predicted by Deubener et al. (2003). Compared to alkalis and alkaline earth elements the effect of protons on glass fragility is small, mainly because of the relatively low concentration of OH groups (max. 1.5 wt% water dissolved as OH) in the glasses.
    Description: Published
    Description: 223-236
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: open
    Keywords: Glass transition ; Pressure effect ; FTIR measurements ; Alkali silicates ; Soda-lime-silica ; Fragility ; Viscosity ; Water in glass ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
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    Water solubility and speciation in shoshonitic and latitic melt composition from Campi Flegrei Caldera (Italy) (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We report new data on water solubility in two melt compositions representative of volcanic units of the Campi Flegrei Caldera (Italy). The first composition is a primitive shoshonite and the second one is a more evolved latitic composition that have been chosen because of their less evolved nature compared to the other erupted products of Campi Flegrei. Water solubility was investigated at pressures from 25 to 200 MPa and 1200 °C following synthesis in an Internal Heated Pressure Vessel (IHPV). The glasses obtained from water-saturated experiments were analysed using both Fourier Transform Infra Red spectroscopy (FTIR) and Karl Fischer Titration (KFT). KFT was used as an independent method to obtain water concentration for the calibration of molar absorptivities of infrared bands at ∼3550 cm−1 (total water), ∼4500 cm−1 (hydroxyl groups) and ∼5200 cm−1 (molecular water). Water solubility in the shoshonitic melts is similar to that of a basalt while a slightly higher water solubility is observed for the latitic composition. As regards the speciation, we have investigated the water speciation for the shoshonitic composition only and we have made a comparison between the data resulting using different molar absorptivities obtained for basaltic compositions similar to our shoshonite.
    Description: Published
    Description: 113–124
    Description: reserved
    Keywords: Water solubility ; Shoshonitic melts ; Latitic melts ; FTIR ; Molar absorptivity ; Water speciation ; 04. Solid Earth::04.01. Earth Interior::04.01.04. Mineral physics and properties of rocks ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
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    Crustal motion along the Eurasia-Nubia plate boundary (2007)
    American Geophysical Union
    Details
    Publication Date: 2017-04-03
    Description: We investigate crustal deformation along the Eurasia-Nubia plate boundary in Calabria and Sicily revealed by the GPS velocity field obtained by the combination of continuous site velocities with previous results from episodic campaigns. We recognize two distinct crustal domains characterized by different motions and styles of deformation. Convergence in Sicily is taken up by crustal shortening along the former Tyrrhenian back arc passive margin, in agreement with seismological data and geological evidence of recent cessation of deformation along the Plio-Pleistocene subduction front. The analysis of the GPS data and the consistency between earthquake slip vectors and convergence direction suggest that Eu-Nu convergence in Sicily does not require intermediate crustal blocks. Significant Eurasia ( 3 mm/yr to NNE) and Nubia-fixed ( 5 mm/yr to ESE) residual velocities in Calabria suggest instead the presence of an intermediate crustal block which can be interpreted as a forearc sliver or as an independent Ionian block. According to the first hypothesis, subduction is still active in the Ionian wedge, although we find no evidence for active back arc spreading in the Tyrrhenian Sea. The N115 E oriented Sicily-Calabria GPS relative motion is consistent with the extension observed during the 1908 Mw 7.1 Messina earthquake. We suggest that up to 3 mm/yr ( 80%) of this estimated relative motion between Sicily and the Calabrian Arc may be taken up in the Messina Straits.
    Description: Published
    Description: 1-16
    Description: reserved
    Keywords: GPS ; Calabria, Sicily, Active tectonics ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
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    Active crustal extension in the central Apennines (Italy) (2007)
    American Geophysical Union
    Details
    Publication Date: 2017-04-04
    Description: We present the first GPS estimate of crustal extension in the central Apennines (Italy) through the analysis of the deformation of a sub-network of the National GPS Geodetic network IGM95 in the interval 1994–1999. The selected sub-network spans the entire active deformation belt perpendicularly to its axis and allows the evaluation of (1) the total extension rate absorbed in this sector of the Apennines and (2) the seismogenic potential of the normal faults active in the Late Pleistocene-Holocene interval within the network. Results of this reoccupation are consistent with an extensional strain rate of 0.18×10−6 yr−1 concentrated in an area of about 35 km width, giving an average extension rate of 6±2 mm/yr across the central Apennines. The pattern of active deformation suggests active elastic strain accumulation on the westernmost of the two fault systems active in the Late Pleistocene-Holocene interval and may also suggest the presence of another active fault system not recognized so far.
    Description: Published
    Description: 2121-2124
    Description: reserved
    Keywords: GPS ; Apennines, Active extension ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
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    Co-seismic displacements associated to the Molise (Southern Italy)earthquake sequence of October–November 2002 inferred from GPS measurements (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The 2002 earthquake sequence of October 31 and November 1 (main shocks Mw=5.7) struck an area of the Molise region in Southern Italy. In this paper we analyzed the co-seismic deformation related to the Molise seismic sequence, inferred from GPS data collected before and after the earthquake, that ruptured a rather deep portion of crust releasing a moderate amount of seismic energy with no surface rupture. The GPS data have been reduced using two different processing strategies and softwares (Bernese and GIPSY) to have an increased control over the result accuracy, since the expected surface displacements induced by the Molise earthquake are in the order of the GPS reliability. The surface deformations obtained from the two approaches are statistically equivalent and show a displacement field consistent with the expected deformation mechanism and with no rupture at the surface. In order to relate this observation with the seismic source, an elastic modeling of fault dislocation rupture has been performed using seismological parameters as constraints to the model input and comparing calculated surface displacements with the observed ones. The sum of the seismic moments (8.9×1017 Nm) of the two main events have been used as a constraint for the size and amount of slip on the model fault while its geometry has been constrained using the focal mechanisms and aftershocks locations. Since the two main shocks exhibit the same fault parameters (strike of the plane, dip and co-seismic slip), we modelled a single square fault, size of 15 km×15 km, assumed to accommodate the whole rupture of both events of the seismic sequence. A vertical E–W trending fault (strike=266°) has been modeled, with a horizontal slip of 120 mm. Sensitivity tests have been performed to infer the slip distribution at depth. The comparison between GPS observations and displacement vectors predicted by the dislocation model is consistent with a source fault placed between 5 and 20 km of depth with a constant pure right-lateral strike-slip in agreement with fault slip distribution analyses using seismological information. The GPS strain field obtained doesn't require a geodetic moment release larger than the one inferred from the seismological information ruling out significant post-seismic deformation or geodetic deformation released at frequencies not detectable by seismic instruments. The Molise sequence has a critical seismotectonic significance because it occurred in an area where no historical seismicity or seismogenic faults are reported. The focal location of the sequence and the strike-slip kinematics of main shocks allow to distinguish it from the shallower and extensional seismicity of the southern Adriatic block from the northern one.
    Description: Published
    Description: 21-35
    Description: JCR Journal
    Description: reserved
    Keywords: GPS ; molise earthquake ; 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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  • 10
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    Calibration of atmospheric effects on SAR interferograms by GPS and local atmosphere models: first results (2007)
    Elsevier
    Details
    Publication Date: 2022-03-02
    Description: A comparison between the ZPD (Zenith Path Delay), obtained from GPS measurements, and the expected delay, derived from models used to compensate tropospheric effects on SAR interferograms, is made. The results of the two methods are comparable, though the available data set is not large enough for a complete statistical validation of the methods. The results of this preliminary study suggest a possible integration of GPS-based ZPD data with cheap and standard meteorological data, since the estimated atmospheric component proved to be similar. Furthermore, the impact on volcanology of the effects measured by GPS, and in particular on the determination of the depth of the volcanic sources, is discussed.
    Description: MADVIEWS EC Project ENV4-CT96-0294
    Description: Published
    Description: 1343-1357
    Description: JCR Journal
    Description: open
    Keywords: SAR ; GPS ; Tropospheric delay ; 01. Atmosphere::01.02. Ionosphere::01.02.05. Wave propagation ; 01. Atmosphere::01.02. Ionosphere::01.02.06. Instruments and techniques ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
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    Kinematics of the Iberia-Maghreb plate contact from seismic moment tensors and GPS (2007)
    Elsevier
    Details
    Publication Date: 2021-09-03
    Description: The Iberian Peninsula and the Maghreb experience moderate earthquake activity and oblique, ∼ NW–SE convergence between Africa and Eurasia at a rate of ∼ 5 mm/yr. Coeval extension in the Alboran Basin and a N35°E trending band of active, left-lateral shear deformation in the Alboran–Betic region are not straightforward to understand in the context of regional shortening, and evidence complexity of deformation at the plate contact. We estimate 86 seismic moment tensors (MW 3.3 to 6.9) from time domain inversion of near-regional waveforms in an intermediate period band. Those and previous moment tensors are used to describe regional faulting style and calculate average stress tensors. The solutions associated to the Trans-Alboran shear zone show predominantly strike-slip faulting, and indicate a clockwise rotation of the largest principal stress orientation compared to the regional convergence direction (σ1 at N350°E). At the N-Algerian and SW-Iberian margins, reverse faulting solutions dominate, corresponding to N350°E and N310°E compression, respectively. Over most of the Betic range and intraplate Iberia, we observe predominately normal faulting, and WSW–ENE extension (σ3 at N240°E). From GPS observations we estimate that more than 3 mm/yr of African (Nubian)–Eurasian plate convergence are currently accommodated at the N-Algerian margin, ∼ 2 mm/yr in the Moroccan Atlas, and ∼ 2 mm/yr at the SW-Iberian margin. 2 mm/yr is a reasonable estimate for convergence within the Alboran region, while Alboran extension can be quantified as ∼ 2.5 mm/yr along the stretching direction (N240°E). Superposition of both motions explains the observed left-lateral transtensional regime in the Trans-Alboran shear zone. Two potential driving mechanisms of differential motion of the Alboran–Betic–Gibraltar domain may coexist in the region: a secondary stress source other than plate convergence, related to regional-scale dynamic processes in the upper mantle of the Alboran region, as well as drag from the continental-scale motion of the Nubian plate along the southern limit of the region. In the Atlantic Ocean, the ∼ 3.5 mm/ yr, westward motion of the Gibraltar Arc relative to intraplate Iberia can be accommodated at the transpressive SW-Iberian margin, while available GPS observations do not support an active subduction process in this area.
    Description: Published
    Description: 295-317
    Description: JCR Journal
    Description: reserved
    Keywords: GPS ; Kinematics ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods
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