Distal deposition of tephra from the Eyjafjallajökull 2010 summit eruption

• Published in: Journal of Geophysical Research: Solid Earth
• Main Authors: Stevenson, John, Loughlin, Susan, Rae, C., Thordarson, Thorvaldur, Milodowski, Antoni, Gilbert, Jennie, Harangi, Szabolcs, Lukács, Reka, Højgaard, Bartal, Árting, Uni, Pyne-O'Donnell, Sean, MacLeod, Alison, Whitney, Bronwen, Cassidy, Mike
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley-Blackwell 2012
• Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences; Bergen; Faroe Islands; Norway; Eyjafjallajökull; Iceland
• Online Access: https://nrl.northumbria.ac.uk/id/eprint/22740/; https://doi.org/10.1029/2011JB008904

The 2010 Eyjafjallajökull lasted 39 days and had 4 different phases, of which the first and third (14–18 April and 5–6 May) were most intense. Most of this period was dominated by winds with a northerly component that carried tephra toward Europe, where it was deposited in a number of locations and was sampled by rain gauges or buckets, surface swabs, sticky-tape samples and air filtering. In the UK, tephra was collected from each of the Phases 1–3 with a combined range of latitudes spanning the length of the country. The modal grain size of tephra in the rain gauge samples was 25 μm, but the largest grains were 100 μm in diameter and highly vesicular. The mass loading was equivalent to 8–218 shards cm−2, which is comparable to tephra layers from much larger past eruptions. Falling tephra was collected on sticky tape in the English Midlands on 19, 20 and 21st April (Phase 2), and was dominated by aggregate clasts (mean diameter 85 μm, component grains <10 μm). SEM-EDS spectra for aggregate grains contained an extra peak for sulphur, when compared to control samples from the volcano, indicating that they were cemented by sulphur-rich minerals e.g. gypsum (CaSO4⋅H2O). Air quality monitoring stations did not record fluctuations in hourly PM10 concentrations outside the normal range of variability during the eruption, but there was a small increase in 24-hour running mean concentration from 21–24 April (Phase 2). Deposition of tephra from Phase 2 in the UK indicates that transport of tephra from Iceland is possible even for small eruption plumes given suitable wind conditions. The presence of relatively coarse grains adds uncertainty to concentration estimates from air quality sensors, which are most sensitive to grain sizes <10 μm. Elsewhere, tephra was collected from roofs and vehicles in the Faroe Islands (mean grain size 40 μm, but 100 μm common), from rainwater in Bergen in Norway (23–91 μm) and in air filters in Budapest, Hungary (2–6 μm). A map is presented summarizing these and other recently published ...