Open Access Research

UK monitoring and deposition of tephra from the May 2011 eruption of Grímsvötn, Iceland

John Alexander Stevenson1*, Susan C Loughlin2, Anna Font3, Gary W Fuller3, Alison MacLeod4, Ian W Oliver5, Ben Jackson6, Claire J Horwell7, Thor Thordarson19 and Ian Dawson8

Author Affiliations

1 School of GeoSciences, The University of Edinburgh, Grant Institute, West Mains Road, Edinburgh, EH9 3JW, UK

2 British Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9 3LA, UK

3 MRC HPA Centre for Environment and Health, King’s College London, 150 Stamford Street, London SE1 9NH, UK

4 Department of Geography, University of London, Royal Holloway, Surrey, UK

5 Scottish Environment Protection Agency, Riccarton, Edinburgh, UK and School of Physical & Geographical Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK

6 Scottish Environment Protection Agency, Riccarton, Edinburgh, UK

7 Department of Earth Sciences, Durham University, Durham, DH1 3LE, UK

8 Met Office, Eskdalemuir, Dumfries and Galloway, DG13 0QW, UK

9 Faculty of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik IS101, Iceland

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Journal of Applied Volcanology 2013, 2:3  doi:10.1186/2191-5040-2-3

Published: 24 May 2013

Abstract

Mapping the transport and deposition of tephra is important for the assessment of an eruption’s impact on health, transport, vegetation and infrastructure, but it is challenging at large distances from a volcano (> 1000 km), where it may not be visible to the naked eye. Here we describe a range of methods used to quantify tephra deposition and impact on air quality during the 21–28 May 2011 explosive basaltic eruption of Grímsvötn volcano, Iceland. Tephra was detected in the UK with tape-on-paper samples, rainwater samples, rainwater chemistry analysis, pollen slides and air quality measurements. Combined results show that deposition was mainly in Scotland, on 23–25 May. Deposition was patchy, with adjacent locations recording different results. Tape-on-paper samples, collected by volunteer citizen scientists, and giving excellent coverage across the UK, showed deposition at latitudes >55°N, mainly on 24 May. Rainwater samples contained ash grains mostly 20–30 μm long (maximum recorded grainsize 80 μm) with loadings of up to 116 grainscm-2. Analysis of rainwater chemistry showed high concentrations of dissolved Fe and Al in samples from N Scotland on 24–27 May. Pollen slides recorded small glass shards (3–4 μm long) deposited during rainfall on 24–25 May and again on 27 May. Air quality monitoring detected increased particulate matter concentrations in many parts of the country. An hourly concentration of particles < 10 μm in diameter (PM10) of ∼413 μgm-3, was measured in Aberdeen at 02:00hrs on 24 May 2011. Significant peaks of non-anthropogenic PM, which is most likely to have a volcanic origin, could be tracked as far south as the English Midlands (> 53°N) on 24 May but no negative effects on health were reported. Although the eruption column reached altitudes of 20 km above sea level, air mass trajectories suggest that only tephra from the lowest 4 km above sea level of the eruption plume was transported to the UK. This demonstrates that even low plumes could deliver tephra to the UK and suggests that the relative lack of basaltic tephra in the tephrochronological record is not due to transport processes.

Keywords:
Tephrochronology; Volcanic ash; PM10; PM 2.5; Citizen science