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dc.contributor.authorHutchison, William
dc.contributor.authorBiggs, Juliet
dc.contributor.authorMather, Tamsin A.
dc.contributor.authorPyle, David M.
dc.contributor.authorLewi, Elias
dc.contributor.authorYirgu, Gezahegn
dc.contributor.authorCaliro, Stefano
dc.contributor.authorChiodini, Giovanni
dc.contributor.authorClor, Laura E.
dc.contributor.authorFischer, Tobias P.
dc.date.accessioned2016-08-19T11:30:19Z
dc.date.available2016-08-19T11:30:19Z
dc.date.issued2016-08
dc.identifier243585354
dc.identifier0a0af43c-21f7-4c33-a150-0031dfb82ff8
dc.identifier84982840815
dc.identifier000384808200004
dc.identifier.citationHutchison , W , Biggs , J , Mather , T A , Pyle , D M , Lewi , E , Yirgu , G , Caliro , S , Chiodini , G , Clor , L E & Fischer , T P 2016 , ' Causes of unrest at silicic calderas in the East African Rift: new constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopia ' , Geochemistry, Geophysics, Geosystems , vol. 17 , no. 8 , pp. 3008-3030 . https://doi.org/10.1002/2016GC006395en
dc.identifier.issn1525-2027
dc.identifier.otherBibtex: urn:a63e11d61a56205b58e5f7d8a92e2655
dc.identifier.urihttps://hdl.handle.net/10023/9338
dc.descriptionThis work is a contribution to the Natural Environment Research Council (NERC) funded RiftVolc project (NE/L013932/1, Rift volcanism: past, present, and future). W.H., J.B., T.A.M., and D.M.P. are supported by and contribute to the NERC Centre for the Observation and Modelling of Earthquakes, Volcanoes, and Tectonics (COMET). Envisat data were provided by ESA. ALOS data were provided through ESA third party mission. W.H. funded by NERC studentship, NE/J5000045/1. Additional funding for fieldwork was provided by University College (University of Oxford), the Geological Remote Sensing Group, the Edinburgh Geological Society, and the Leverhulme Trust. Analytical work at the University of New Mexico was supported by the Volcanic and Geothermal Volatiles Lab at the Center for Stable Isotopes and an NSF grant EAR-1113066 to T.P.F.en
dc.description.abstractRestless silicic calderas present major geological hazards, and yet many also host significant untapped geothermal resources. In East Africa this poses a major challenge, although the calderas are largely unmonitored their geothermal resources could provide substantial economic benefits to the region. Understanding what causes unrest at these volcanoes is vital for weighing up the opportunities against the potential risks. Here we bring together new field and remote sensing observations to evaluate causes of ground deformation at Aluto, a restless silicic volcano located in the Main Ethiopian Rift (MER). Interferometric Synthetic Aperture Radar (InSAR) data reveal the temporal and spatial characteristics of a ground deformation episode that took place between 2008 and 2010. Deformation time-series reveal pulses of accelerating uplift that transition to gradual long-term subsidence, and analytical models support inflation source depths of ∼5 km. Gases escaping along the major fault zone of Aluto show high CO2 flux, and a clear magmatic carbon signature (CO2–δ13C of −4.2 to −4.5 ‰). This provides compelling evidence that the magmatic and hydrothermal reservoirs of the complex are physically connected. We suggest that a coupled magmatic-hydrothermal system can explain the uplift-subsidence signals. We hypothesize that magmatic fluid injection and/or intrusion in the cap of the magmatic reservoir drives edifice wide inflation while subsequent deflation is related to magmatic degassing and depressurization of the hydrothermal system. These new constraints on the plumbing of Aluto yield important insights into the behaviour of rift volcanic systems and will be crucial for interpreting future patterns of unrest.
dc.format.extent2465541
dc.language.isoeng
dc.relation.ispartofGeochemistry, Geophysics, Geosystemsen
dc.subjectGeothermal resourcesen
dc.subjectInSARen
dc.subjectDegassingen
dc.subjectContinental riftingen
dc.subjectMagmatic processesen
dc.subjectGE Environmental Sciencesen
dc.subjectDASen
dc.subject.lccGEen
dc.titleCauses of unrest at silicic calderas in the East African Rift: new constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopiaen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. Earth and Environmental Sciencesen
dc.identifier.doi10.1002/2016GC006395
dc.description.statusPeer revieweden
dc.identifier.urlhttp://onlinelibrary.wiley.com/doi/10.1002/2016GC006395/full#footer-support-infoen


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