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Publications (10 of 19) Show all publications
Rhodes, E., Burchardt, S., Parker, C. F., Barker, A. & Dahrén, B. (2019). What is the role of Wiki during volcanic eruptions?. In: : . Paper presented at Wikimania 2019, August 14-18 2019, Stockholm, Sweden.
Open this publication in new window or tab >>What is the role of Wiki during volcanic eruptions?
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

A team of scientists from the Centre of Natural Hazards and Disaster Science (www.cnds.se) and Uppsala University are planning a study on the role of Wikipedia during volcanic eruptions.

Pageview statistics show a spike of up to 200 000 views (e.g. Anak Krakatau eruption and associated tsunami in December 2018) at the onset of a volcanic event. In acknowledgement of this, the team want to explore the role of Wikipedia as a disaster response resource during such events, when accurate and readily accessible information can save lives. The poster will outline our current approach to this project, propose suitable methods and illustrate the work in progress.

Keywords
wikipedia, disaster response, hazard mitigation, social volcanoology
National Category
Geosciences, Multidisciplinary Sociology
Identifiers
urn:nbn:se:uu:diva-392171 (URN)
Conference
Wikimania 2019, August 14-18 2019, Stockholm, Sweden
Available from: 2019-08-30 Created: 2019-08-30 Last updated: 2019-08-30Bibliographically approved
Andrén, M., Stockmann, G., Skelton, A., Sturkell, E., Mörth, C.-M., Guðrúnardóttir, H. R., . . . Kockum, I. (2016). Coupling between mineral reactions, chemical changes in groundwater, and earthquakes in Iceland. Journal of Geophysical Research - Solid Earth, 121(4), 2315-2337
Open this publication in new window or tab >>Coupling between mineral reactions, chemical changes in groundwater, and earthquakes in Iceland
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2016 (English)In: Journal of Geophysical Research - Solid Earth, ISSN 2169-9313, E-ISSN 2169-9356, Vol. 121, no 4, p. 2315-2337Article in journal (Refereed) Published
Abstract [en]

Chemical analysis of groundwater samples collected from a borehole at Hafralækur, northernIceland, from October 2008 to June 2015 revealed (1) a long-term decrease in concentration of Si and Naand (2) an abrupt increase in concentration of Na before each of two consecutive M > 5 earthquakes whichoccurred in 2012 and 2013, both 76 km from Hafralækur. Based on a geochemical (major elements and stableisotopes), petrological, and mineralogical study of drill cuttings taken from an adjacent borehole, we areable to show that (1) the long-term decrease in concentration of Si and Na was caused by constant volumereplacement of labradorite by analcime coupled with precipitation of zeolites in vesicles and along fracturesand (2) the abrupt increase of Na concentration before the first earthquake records a switchover tononstoichiometric dissolution of analcime with preferential release of Na into groundwater. We attributedecay of the Na peaks, which followed and coincided with each earthquake to uptake of Na along fracturedor porous boundaries between labradorite and analcime crystals. Possible causes of these Na peaks are anincrease of reactive surface area caused by fracturing or a shift from chemical equilibrium caused by mixingbetween groundwater components. Both could have been triggered by preseismic dilation, which was alsoinferred in a previous study by Skelton et al. (2014). The mechanism behind preseismic dilation so far from thefocus of an earthquake remains unknown.

Keywords
geochemistry, Iceland, groundwater, earthquakes, mineralogy
National Category
Geochemistry
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-291373 (URN)10.1002/2015JB012614 (DOI)000381626700007 ()
Funder
Swedish Research Council
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2017-11-30Bibliographically approved
Dahrén, B. (2016). Magma plumbing architecture in Indonesia and the North Atlantic Igneous Province. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Magma plumbing architecture in Indonesia and the North Atlantic Igneous Province
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Magma plumbing systems represent the physical framework of magma transport and storage from the source region in the mantle, through the crust, until reaching the surface in a volcanic eruption. Characterising the different aspects of magma plumbing, in particular the distribution of magma storage zones throughout the crust, is of key importance to better understand the behaviour of individual volcanoes. In particular, shallow crustal magma storage and associated magma-crust interaction processes could potentially explain some of the worlds most unpredictable and explosive volcanoes. This thesis studies magma plumbing architecture in the Sunda Arc (Indonesia), and the North Atlantic Igneous Province, based on elemental and isotope geochemistry, and derived petrological modelling.

In this study, I have employed petrological models, so called geothermobarometers, to calculate pressures and temperatures (P-T) of crustal magma storage. Geothermobarometers are calibrated thermodynamic formulations based on the composition of magmatic minerals and their co-existing melt as a function of the P-T conditions of crystallisation. Using the calculated P-T estimates, I was able to derive the depth of magma storage, and thereby reconstruct the architecture of magma storage systems. A number of different geothermobarometers based on different mineral phases, including plagioclase, clinopyroxene and olivine, were used for this purpose,

The geothermobarometric modelling was combined with additional elemental and isotope geochemical analyses, as well as collaborations with geophysical investigations. These additional approaches were used to corroborate the findings of the geothermobarometric modelling, and also to model and quantify magma-crust interaction processes that take place during crustal magma storage, such as assimilation of crustal lithologies into the magmatic system.

The findings of this thesis build upon the growing body of evidence in support of the prevalence of shallow magma storage in different volcanic settings worldwide. This realisation is relevant to volcano monitoring and hazard mitigation worldwide.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. p. 46
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1328
Keywords
magma plumbing, geothermobarometry, plagioclase, clinopyroxene, magma-crust interaction, hazard mitigation
National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-267764 (URN)978-91-554-9430-8 (ISBN)
Public defence
2016-01-28, Hambergsalen, Geocentrum, Villavägen 16, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2016-01-04 Created: 2015-11-26 Last updated: 2017-07-12
Budd, D. A., Troll, V., Dahren, B. & Burchardt, S. (2016). Persistent multitiered magma plumbing beneath Katla volcano, Iceland. Geochemistry Geophysics Geosystems, 17(3), 966-980
Open this publication in new window or tab >>Persistent multitiered magma plumbing beneath Katla volcano, Iceland
2016 (English)In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 17, no 3, p. 966-980Article in journal (Refereed) Published
Abstract [en]

Recent seismic unrest and a persistent Holocene eruption record at Katla volcano, Iceland indicate that a near-future eruption is possible. Previous petrological investigations suggest that Katla is supplied by a simple plumbing system that delivers magma directly from depth, while seismic and geodetic data also point toward the existence of upper-crustal magma storage. To characterize Katla's recent plumbing system, we established mineral-melt equilibrium crystallization pressures from four age-constrained Katla tephras spanning from 8 kyr BP to 1918. The results point to persistent shallow- (≤8 km depth) as well as deep-crustal (ca. 10 – 25 km depth) magma storage beneath Katla throughout the last 8 kyr. The presence of multiple magma storage regions implies that mafic magma from the deeper reservoir system may become gas-rich during ascent and storage in the shallow crust and erupt explosively. Alternatively, it might intersect evolved magma pockets in the shallow-level storage region, and so increase the potential for explosive mixed-magma ash eruptions.

Keywords
Katla volcano; mineral-melt equilibrium thermobarometry; persistent multi-tiered magma plumbing system
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-285922 (URN)10.1002/2015GC006118 (DOI)000375144700019 ()
Funder
Swedish Research CouncilThe Royal Swedish Academy of Sciences
Available from: 2016-04-27 Created: 2016-04-20 Last updated: 2017-11-30Bibliographically approved
Troll, V., Deegan, F., Jolis, E. M., Budd, D., Dahrén, B. & Schwarzkopf, L. (2015). Ancient oral tradition describes volcano-earthquake interaction at Merapi volcano, Indonesia.. Geografiska Annaler. Series A, Physical Geography, 97(1), 137-166
Open this publication in new window or tab >>Ancient oral tradition describes volcano-earthquake interaction at Merapi volcano, Indonesia.
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2015 (English)In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 97, no 1, p. 137-166Article in journal (Refereed) Published
National Category
Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240752 (URN)10.1111/geoa.12099 (DOI)000350500400010 ()
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2017-12-05Bibliographically approved
Jamshidi, K., Ghasemi, H., Troll, V., Sadeghian, M. & Dahrén, B. (2015). Magma storage and plumbing of adakite-type post-ophiolite intrusions in the Sabzevar ophiolitic zone, northeast Iran. Solid Earth, 6(1), 49-72
Open this publication in new window or tab >>Magma storage and plumbing of adakite-type post-ophiolite intrusions in the Sabzevar ophiolitic zone, northeast Iran
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2015 (English)In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 6, no 1, p. 49-72Article in journal (Refereed) Published
Abstract [en]

Subduction-related adakite-type intrusive rocks emplaced into the late Cretaceous-Paleocene Sabzevar ophiolite zone, northeast Iran, range from Mg-andesite to rhyodacite in composition. Here we investigate the magma supply system to these subvolcanic intrusive rocks by applying thermobarometric mineral and mineral-melt equilibrium models, including amphibole thermobarometry, plagioclase-melt thermobarometry and clinopyroxene-melt barometry. Based on the results of these thermobarometric models, plagioclase crystallized dominantly at pressures of similar to 350 (130 to 468) MPa, while amphiboles record both low pressures (similar to 300 MPa) and very high pressures (> 700 MPa) of crystallization. The latter is supported by the calculated pressures for clinopyroxene crystallization (550 to 730 MPa). The association of amphibole with clinopyroxene and no plagioclase in the most primitive samples (Mg-andesites) is consistent with amphibole fractionation from very hydrous magmas at deep crustal levels of the plumbing system, which may have been a key process in intensifying adakite-type affinities in this rock suite. Barometry, combined with frequent disequilibrium features such as oscillatory-zoned and sieve-textured plagioclase crystals with An-rich overgrowths in more evolved samples, implies that final magma differentiation occurred in an open upper crustal magma system that developed progressively stronger compositional modifications during high-level magma storage.

National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-252267 (URN)10.5194/se-6-49-2015 (DOI)000352161500004 ()
Available from: 2015-05-05 Created: 2015-05-04 Last updated: 2017-12-04
Weis, F. A., Skogby, H., Troll, V., Deegan, F. & Dahrén, B. (2015). Magmatic water contents determined through clinopyroxene: Examples from the Western Canary Islands, Spain. Geochemistry Geophysics Geosystems, 16(7), 2127-2146
Open this publication in new window or tab >>Magmatic water contents determined through clinopyroxene: Examples from the Western Canary Islands, Spain
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2015 (English)In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 16, no 7, p. 2127-2146Article in journal (Refereed) Published
Abstract [en]

Water is a key parameter in magma genesis, magma evolution, and resulting eruption styles, because it controls the density, the viscosity, as well as the melting and crystallization behavior of a melt. The parental water content of a magma is usually measured through melt inclusions in minerals such as olivine, a method which may be hampered, however, by the lack of melt inclusions suitable for analysis, or postentrapment changes in their water content. An alternative way to reconstruct the water content of a magma is to use nominally anhydrous minerals (NAMs), such as pyroxene, which take up low concentrations of hydrogen as a function of the magma's water content. During magma degassing and eruption, however, NAMs may dehydrate. We therefore tested a method to reconstruct the water contents of dehydrated clinopyroxene phenocrysts from the Western Canary islands (n=28) through rehydration experiments followed by infrared and Mossbauer spectroscopy. Employing currently available crystal/melt partitioning data, the results of the experiments were used to calculate parental water contents of 0.710.07 to 1.490.15 wt % H2O for Western Canary magmas during clinopyroxene crystallization at upper mantle conditions. This H2O range is in agreement with calculated water contents using plagioclase-liquid-hygrometry, and with previously published data for mafic lavas from the Canary Islands and comparable ocean island systems elsewhere. Utilizing NAMs in combination with hydrogen treatment can therefore serve as a proxy for pre-eruptive H2O contents, which we anticipate becoming a useful method applicable to mafic rocks where pyroxene is the main phenocryst phase.

Keywords
Canary Islands, NAMs, clinopyroxene, hydrogen, magmatic water content
National Category
Geophysics Geochemistry
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-263041 (URN)10.1002/2015GC005800 (DOI)000360247200007 ()2-s2.0-84938855029 (Scopus ID)
Funder
Swedish Research CouncilThe Royal Swedish Academy of SciencesSwedish Research Council
Available from: 2015-09-29 Created: 2015-09-24 Last updated: 2017-12-01Bibliographically approved
Dahrén, B., Troll, V., Barker, A., Meade, F. C., Holm, P. M. & Søager, N. (2015). Plagioclase mineral chemistry in the Faroe Islands Basalt Group. Paper presented at The 4th Faroe Islands Exploration Conference, Torshavn, Faroe Islands, 1-2 May 2012. Faroe Islands Exploration Conference: Proceedings of the 4th Conference
Open this publication in new window or tab >>Plagioclase mineral chemistry in the Faroe Islands Basalt Group
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2015 (English)In: Faroe Islands Exploration Conference: Proceedings of the 4th ConferenceArticle in journal (Refereed) In press
Keywords
plagioclase, magma plumbing, Large Igneous Province
National Category
Geology Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-267639 (URN)
Conference
The 4th Faroe Islands Exploration Conference, Torshavn, Faroe Islands, 1-2 May 2012
Available from: 2015-11-25 Created: 2015-11-25 Last updated: 2016-01-13
Dahrén, B., Burchardt, S., Troll, V., Emeleus, C., Mattson, T. & Berg, S. (2014). 3D-model of the Rum central complex. In: : . Paper presented at Volcanic and Magmatic Studies Group Annual Meeting.
Open this publication in new window or tab >>3D-model of the Rum central complex
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2014 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Geology Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240938 (URN)
Conference
Volcanic and Magmatic Studies Group Annual Meeting
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-01-08
Troll, V., Deegan, F., Jolis, E. M., Dahrén, B., Blythe, L., Harris, C., . . . Freda, C. (2014). Magma storage at Krakatau volcanic complex. In: : . Paper presented at City On volcanoes.
Open this publication in new window or tab >>Magma storage at Krakatau volcanic complex
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2014 (English)Conference paper, Oral presentation only (Refereed)
National Category
Geology Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240897 (URN)
Conference
City On volcanoes
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-01-08
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