GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Article
    Article
    Changes in eruptive style during the A.D. 1538 Monte Nuovo eruption (Phlegrean Fields, Italy): the role of syn-eruptive crystallization, (2005)
    Associated volumes
    Details Availability
    In: Bulletin of volcanology, Berlin : Springer, 1986, 67(2005), Seite 601-621, 0258-8900
    In: volume:67
    In: year:2005
    In: pages:601-621
    Type of Medium: Article
    ISSN: 0258-8900
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GEOMAR CATALOGUE
    Link to Library Catalog
    get availability status
  • 2
    Electronic Resource
    Electronic Resource
    Role of carbon dioxide in the dynamics of magma ascent in explosive eruptions (1999)
    Springer
    Bulletin of volcanology 60 (1999), S. 583-594 
    Details
    ISSN: 1432-0819
    Keywords: Key words Carbon dioxide ; Magma ascent ; Explosive eruptions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The role of carbon dioxide in the dynamics of magma ascent in explosive eruptions is investigated by means of numerical modeling. The model is steady, one-dimensional, and isothermal; it calculates the separated flow of gas and a homogeneous mixture of liquid magma and crystals. The magma properties are calculated on the basis of magma composition and crystal content and are allowed to change along the conduit due to pressure decrease and gas exsolution. The effect of the presence of a two-component (water + carbon dioxide) exsolving gas phase is investigated by performing a parametric study on the CO2/(H2O+CO2) ratio, which is allowed to vary from 0 to 0.5 at either constant total volatile or constant water content. The relatively insoluble carbon dioxide component plays an important role in the location of the volatile-saturation and magma-fragmentation levels and in the distribution of the flow variables in the volcanic conduit. In detail, the results show that an increase of the proportion of carbon dioxide produces a decrease of the mass flow rate, pressure, and exit mixture density, and an increase of the exit gas volume fraction and depth of the fragmentation level. A relevant result is the different role played by water and carbon dioxide in the eruption dynamics; an increasing amount of water produces an increase of the mass flow rate, and an increasing amount of carbon dioxide produces a decrease. Even small amounts of carbon dioxide have major consequences on the eruption dynamics, implying that the multicomponent nature of the volcanic gas must be taken into account in the prediction of the eruption scenario and the forecasting of volcanic hazard.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004450050253
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    A study on the reproducibility of counting vesicles in volcanic rocks (2011)
    Geological Society of America (GSA)
    Details
    Publication Date: 2011-02-01
    Description: Vesicle size distributions in two and three dimensions of two samples were independently measured by three different researchers to investigate whether or not such measurements are reproducible. Additionally, two different software programs were used to measure the three-dimensional vesicle size distributions: the 3D Object Counter plugin for ImageJ and Blob3D. Manual thresholding by each of the authors produced similar results for both samples using both programs; however, use of the automatic, maximum entropy technique for thresholding produced measurably different results because it did not discriminate between vesicles and plagioclase crystals in one case and between vesicles and some cracks in another. Use of asymmetric erosion and dilation processes on the images is shown to affect the vesicle size distribution, but it does not have a significant effect on the power-law exponent that describes intermediate-sized vesicles or on the vesicle number density in these samples. However, such a technique is not recommended.
    Electronic ISSN: 1553-040X
    Topics: Geosciences
    Published by Geological Society of America (GSA)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Explosivity of basaltic lava fountains is controlled by magma rheology, ascent rate and outgassing (2020)
    Elsevier
    Details
    Publication Date: 2021-03-30
    Description: The dichotomy between explosive volcanic eruptions, which produce pyroclasts, and effusive eruptions, which produce lava, is defined by the presence or absence of fragmentation during magma ascent. For lava fountains the distinction is unclear, since the liquid phase in the rising magma may remain continuous to the vent, fragment in the fountain, then re-weld on deposition to feed rheomorphic lava flows. Here we use a numerical model to constrain the controls on basaltic eruption style, using Kilauea and Etna as case studies. Based on our results, we propose that lava fountaining is a distinct style, separate from effusive and explosive eruption styles, that is produced when magma ascends rapidly and fragments above the vent, rather than within the conduit. Sensitivity analyses of Kilauea and Etna case studies show that high lava fountains (〉50 m high) occur when the Reynolds number of the bubbly magma is greater than ∼0.1, the bulk viscosity is less than 10^6, and the gas is well-coupled to the melt. Explosive eruptions (Plinian and sub-Plinian) are predicted over a wide region of parameter space for higher viscosity basalts, typical of Etna, but over a much narrower region of parameter space for lower viscosity basalts, typical of Kilauea. Numerical results show also that the magma that feeds high lava fountains ascends more rapidly than the magma that feeds explosive eruptions, owing to its lower viscosity. For the Kilauea case study, waning ascent velocity is predicted to produce a progressive evolution from high to weak fountaining, to ultimate effusion; whereas for the Etna case study, small changes in parameter values lead to transitions to and from explosive activity, suggesting that eruption transitions may occur with little warning.
    Description: RCUK NERC DisEqm project
    Description: Published
    Description: 116658
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    MeMoVolc consensual document: a review of cross-disciplinary approaches to characterizing small explosive magmatic eruptions (2019)
    Details
    Publication Date: 2021-06-25
    Description: A workshop entitled “Tracking and understanding volcanic emissions through cross37 disciplinary integration: A textural working group.” was held at the Université Blaise Pascal (Clermont-Ferrand, France) on the 6-7th November 2012. This workshop was supported by the European Science Foundation (ESF). The main objective of the workshop was to establish an initial advisory group to begin to define measurements, methods, formats and standards to be applied in the integration of geophysical, physical and textural data collected during volcanic eruptions so as to homogenize procedures to be applied and integrated during both past and ongoing events. The working group comprised a total of 35 scientists from six countries (France, Italy, Great Britain, Germany, Switzerland and Iceland). The group comprised eleven advisors from the textural analysis field, eleven from deposit studies, seven geochemists and six geophysicists. The four main aims were to discuss and define: 1) Standards, precision and measurement protocols for textural analysis; 2) Identify textural, field deposit, chemistry and geophysical parameters that can best be measured and combined; 3) Agree on the best delivery formats so that data can be sheared between, and easily used by, each group; 4) Review multi-disciplinary sampling and measurement routines currently used, and measurement standards applied, by each community. The group agreed that community-wide cross-disciplinary integration, centered on defining those measurements and formats that can be best combined, is an attainable but key global focus. Consequently, we prepared a final document to be used as the foundation for a larger, international textural working group to serve as the basis of fully realizing such a pandisciplinary goal in volcanology. Thus, we here report our initial conclusions and recommendations.
    Description: Published
    Description: 49
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Mechanisms of Ash Generation at Basaltic Volcanoes: The Case of Mount Etna, Italy (2020)
    Details
    Publication Date: 2020-02-06
    Description: Basaltic volcanism is the most widespread volcanic activity on Earth and planetary bodies. On Earth, eruptions can impact global and regional climate, and threaten populations living in their shadow, through a combination of ash, gas and lava. Ash emissions are a very typical manifestation of basaltic activity; however, despite their frequency of occurrence, a systematic investigation of basaltic ash sources is currently incomplete. Here, we revise four cases of ash emissions at Mount Etna linked with the most common style of eruptive activity at this volcano: lava fountains (4–5 September 2007), continuous Strombolian activity transitioning to pulsing lava fountaining (24 November 2006), isolated Strombolian explosions (8 April 2010), and continuous to pulsing ash explosions (last phase of 2001 eruption). By combining observations on the eruptive style, deposit features and ash characteristics, we propose three mechanisms of ash generation based on variations in the magma mass flow rate. We then present an analysis of magma residence time within the conduit for both cylindrical and dike geometry, and find that the proportion of tachylite magma residing in the conduit is very small compared to sideromelane, in agreement with observations of ash componentry for lava fountain episodes at Mount Etna. The results of this study are relevant to classify ash emission sources and improve hazard mitigation strategies at basaltic volcanoes where the explosive activity is similar to Mount Etna.
    Description: Published
    Description: Article 193
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    The unexpected explosive sub-Plinian eruption of Calbuco volcano (22–23 April 2015; southern Chile): Triggering mechanism implications (2020)
    Details
    Publication Date: 2020-02-24
    Description: Plinian-type eruptions are extremely hazardous, producing pyroclastic fallout and flows extending many kilometres from the vent. The most commonly invoked eruption trigger for Plinian-type eruptions is the intrusion of fresh magma, generally associated with precursory ground deformation and seismicity days/weeks before eruption. Closed-system internal triggering has also been proposed, such as protracted crystallisation of magma, which can produce a build-up of exsolved volatiles and thus pressurise the system prior to eruption. On 22–23 April 2015 Calbuco volcano, Chile, produced a sub-Plinian eruption with 〈3 h seismic precursory activity and no clear deformation signals in the preceding months. Here, we show that petrological and geochemical evidence do not support a hypothesis of eruption triggering due to pre-eruptive intrusion of fresh magma, but instead are consistent with an internal trigger. We found that basaltic andesitic magma was stored at depths between 8 and 12 km (i.e. 230–320 MPa) beneath Calbuco volcano before the 2015 eruption. The stored magma had an initial temperature of 900–950 °C, was water-saturated (5.5–6.5 wt% H2O) and formed phenocrysts of titanomagnetite, orthopyroxene, clinopyroxene and plagioclase cores (An78–93). Gradual cooling of the magma chamber produced thermal gradients and magma convection, evidenced by plagioclase overgrowth rims (An58–77) and blocky microlites (25–250 μm). Our interpretation is that this continuing crystallisation induced second boiling and an over-pressurisation of the system, leading to the rapid onset of the 2015 eruption. Petrological and geochemical evidence therefore shows that a closed-system magma chamber can evolve into a highly explosive eruption with very little precursory warning, posing a challenge for current volcano monitoring paradigms. We propose that internal triggering should be carefully considered as a mechanism for unexpected sub-Plinian eruptions, prompting a potential revision of existing hazard management strategies.
    Description: Published
    Description: 35-50
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Calbuco ; Sub-Plinian eruption ; Internal trigger ; Crystallisation ; Volcanic hazard ; 04.08. Volcanology ; Petrology ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    From magma ascent to ash generation: investigating volcanic conduit processes by integrating experiments, numerical modeling, and observations (2018)
    Details
    Publication Date: 2021-09-03
    Description: Processes occurring in volcanic conduits, the pathways through which magma travels from its storage region to the surface, have a fundamental control on the nature of eruptions and associated phenomena. It has been well established that magma flows, crystallizes, degasses, and fragments in conduits, that fluids migrate in and out of conduits, and that seismic and acoustic waves are generated and travel within conduits. A better understanding of volcanic conduits and related processes is of paramount importance for improving eruption forecasting, volcanic hazard assessment and risk mitigation. However, despite escalating advances in the characterization of individual conduit processes, our understanding of their mutual interactions and the consequent control on volcanic activity is still limited. With the purpose of addressing this topic, a multidisciplinary workshop led by a group of international scientists was hosted from 25 to 27 October 2014 by the Pisa branch of the Istituto Nazionale di Geofisica e Vulcanologia under the sponsorship of the MeMoVolc Research Networking Programme of the European Science Foundation. The workshop brought together the experimental, theoretical, and observational communities devoted to volcanological research. After 3 days of oral and poster presentations, breakout sessions, and plenary discussions, the participants identified three main outstanding issues common to experimental, analytical, numerical, and observational volcanology: unsteadiness (or transience), disequilibrium, and uncertainty. A key outcome of the workshop was to identify the specific knowledge areas in which exchange of information among the subdisciplines would lead to efficient progress in addressing these three main outstanding issues. It was clear that multidisciplinary collaboration of this sort is essential for progressing the state of the art in understanding of conduit magma dynamics and eruption behavior. This holistic approach has the ultimate aim to deliver fundamental improvements in understanding the underlying processes generating and controlling volcanic activity.
    Description: Published
    Description: S0666
    Description: 4V. Dinamica dei processi pre-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    A novel protocol for resolving feldspar crystals in synchrotron X-ray microtomographic images of crystallized natural magmas and synthetic analogs (2019)
    Mineralogical Society of America
    Details
    Publication Date: 2021-09-03
    Description: X‑ray computed microtomography is a non-destructive imaging technique recognized in the geosciences as a powerful tool to investigate rock textures directly in three dimensions (3D) at the micrometer and sub-micrometer scale. The quantitative morphological and textural analysis of images requires segmentation and characterization of phases in the reconstructed volume based upon their gray levels (related to their relative X‑ray attenuation) and/or morphological aspects. Often the differences in X‑ray attenuation of some phases are so small that no contrast is observed in the reconstructed slices or, although the human eye can discern the differences between these phases, it is difficult, or sometimes impossible, to reliably segment and separately analyze these phases. Facing this challenge, we propose an experimental and computational procedure that allows the segmentation of phases with small density variations in geomaterials. By using an experimental protocol based on phase-contrast synchrotron X‑ray microtomography combined with a customized 3D image processing procedure, we successfully segmented feldspar from the glassy matrix in both a natural volcanic sample and a synthetic analog. Our results demonstrate that crystallized natural volcanic rocks and synthetic analogs can be characterized by synchrotron X‑ray phase-contrast microtomography and that phase-retrieval processing is an invaluable tool for the reconstruction of 3D multiphase textures.
    Description: Elettra- proposal no. 20120015
    Description: Published
    Description: 2301–2311
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Keywords: Synchrotron X‑ray microtomography ; Phase-contrast X‑ray imaging ; Phase-retrieval ; 3D rock textures ; Crystallization ; Feldspars ; Synchrotron X-ray microtomographic images of crystallized natural magmas
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    Determining the Effect of Varying Magmatic Volatile Content on Lunar Magma Ascent Dynamics (2021)
    Wiley-AGU
    Details
    Publication Date: 2021-12-15
    Description: The Moon is not volcanically active at present, therefore, we rely on data from lunar samples, remote sensing, and numerical modeling to understand past lunar volcanism. The role of different volatile species in propelling lunar magma ascent and eruption remains unclear. We adapt a terrestrial magma ascent model for lunar magma ascent, considering different compositions of picritic magmas and various abundances of H 2 , H 2 O, and CO (measured and estimated) for these magmas. We also conduct a sensitivity analysis to investigate the relationship between selected input parameters (pre-eruptive pressure, temperature, conduit radius, and volatile content) and given outputs (exit gas volume fraction, velocity, pressure, and mass eruption rate). We find that, for the model simulations containing H2O and CO, CO was more significant than H2O in driving lunar magma ascent, for the range of volatile contents considered here. For the simulations containing H2 and CO, H2 had a similar or slightly greater control than CO on magma ascent dynamics. Our results showed that initial H2 and CO content has a strong control on exit velocity and pressure, two factors that strongly influence the formation of an eruption plume, pyroclast ejection, and overall deposit morphology. Our results highlight the importance of (a) quantifying and determining the origin of CO, and (b) understanding the abundance of different H-species present within the lunar mantle. Quantifying the role of volatiles in driving lunar volcanism provides an important link between the interior volatile content of the Moon and the formation of volcanic deposits on the lunar surface.
    Description: Published
    Description: e2021JE006939
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...