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Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
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- PublicationRestrictedScanning tomography of SO2 distribution in a volcanic gas plume(2008-09-10)
; ; ; ; ;Wright, T. E.; Department of Earth Sciences, University of Cambridge, Cambridge, UK ;Burton, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Pyle, D. M.; Department of Earth Sciences, University of Oxford, Oxford, UK ;Caltabiano, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; Two-dimensional cross sections of the sulphur dioxide (SO2) distribution in the volcanic gas plume of Mt. Etna were reconstructed using tomographic techniques. The data for these projections were generated by a network of five automated scanning spectrometers, positioned on the flanks of the volcano. These measure slant-column amounts of SO2 at 105 different angles, every four minutes. Stable wind conditions allow the plume to be monitored on 82% of days. A time-series of plume cross sections was computed, revealing the potential of this method to track variations in plume position and structure on timescales of minutes to hours, a result of potential importance for air traffic and civil defence in case of eruption, when copious amounts of fine ash can be transported.219 22 - PublicationRestrictedVisualising volcanic gas plumes with virtual globes(2009)
; ; ; ; ;Wright, T.; University of Cambridge ;Burton, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Pyle, D. M.; University of Oxford ;Caltabiano, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; The recent availability of small, cheap ultraviolet spectrometers has facilitated the rapid deployment of automated networks of scanning instruments at several volcanoes, measuring volcanic SO2 gas flux at high frequency. These networks open up a range of other applications, including tomographic reconstruction of the gas distribution which is of potential use for both risk mitigation, particularly to air traffic, and environmental impact modelling. Here we present a methodology for visualising reconstructed plumes using virtual globes, such as GoogleEarth, which allows animations of the evolution of the gas plume to be displayed and easily shared on a common platform. We detail the process used to convert tomographically reconstructed cross-sections into animated gas plume models, describe how this process is automated and present results from the scanning network around Mt.Etna, Sicily. We achieved an average rate of one frame every12 min, providing a good visual representation of the plume which can be examined from all angles. Increating these models, an approximation to turbulent diffusion in the atmosphere was required. To this end we derived the value of the turbulent diffusion coefficient for quiescent conditions near Etna to be around 200–500 m2s-1.158 32 - PublicationRestrictedSweet chestnut (Castanea sativa) leaves as a bio-indicator of volcanic gas, aerosol, and ash deposition onto the flanks of Mt. Etna in 2005-2007(2009-01-15)
; ; ; ; ; ; ; ; ; ;Martin, R. S.; Department of Earth Sciences, University of Cambridge, Cambridge, UK. ;Mather, T. A.; Department of Earth Sciences, University of Oxford, Oxford, UK. ;Pyle, D. M.; Department of Earth Sciences, University of Oxford, Oxford, UK. ;Watt, S. F. L.; Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR, UK ;Day, J. A.; Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK ;Collins, S. J.; Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK ;Wright, T. E.; Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK ;Aiuppa, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Calabrese, S.; CFTA- Dipt. Chimica e Fisica della Terra e Applicazioni alle Georisorse, Università degli Studi di Palermo, Via Archirafi 36, 90123, Italy, INGV- Sezione di Palermo, Via La Malfa 153, 90146, Italy; ; ; ; ; ; ; ; Sweet chestnut leaves (Castanea sativa) collected from the flanks of Mt Etna volcano in 2005–2007 were analysed by inductively-coupled plasma mass spectrometry to investigate the spatial and temporal variability of element concentrations. The aim of this work was to determine whether these leaves are a bio-indicator for volcanic gas, aerosol and ash deposition and to gain new insights into the environmental effects of quiescent and eruptive volcanic plumes. Results show a positive correlation between sample variability in the concentration of elements in Castanea sativa and enrichment factors of elements in the plume. The spatial and temporal variability of chalcophilic elements (As, Cd, Cu, Mo, Tl, Zn) is consistent with prevailing winds transporting eruptive plumes to the south-east of the summit, resulting in enhanced plume deposition onto the flanks of the volcano. Similar spatial and temporal variability was found for the halideforming elements (Cs, K, Rb) and intermediate elements (Al, Co, Mn). The spatial variability of chalcophilic, intermediate and halide-forming elements during quiescent periods was diminished (relative to eruptive periods) and could not be explained by plume deposition. In contrast, the concentrations of lithophilic elements (Ba, Ca, Mg, Sr) did not show any clear spatial variability even during eruptive periods. Comparisons between enrichment factors for elements in Castanea sativa and literature values for enrichment factors of the volcanic plume, groundwater and lichen were made. Whilst Castanea sativa offers insights into the spatial and temporal variability of deposition, the species may not be a bio-indicator for plume composition due to biological fractionation.336 16