Friday, 19 December 2014

Live monitoring of flood basalts... by Evgenia Ilyinskaya

Evgenia at the eruption site in Holuhraun, Iceland
September 2014
 
Remember the volcanic eruption at Holuhraun, Iceland which started back in the summer? Now, three months later, it’s still ongoing and has reached a size category called ‘flood basalts’  (>1 km3 erupted lava). It is now the largest flood basalt in Iceland since the Laki eruption in 1783-84, which caused the deaths of >20% of the Icelandic population by environmental pollution and famine and likely increased European levels of mortality through air pollution by sulphur-bearing gas and aerosol.

This is the first time in the modern age we have the opportunity to study the environmental impact of a flood basalt  as it happens. Now Dr Evgenia Ilyinskaya (pictured above), from the BGS Volcanology team, has led and won her first ever NERC research grant to allow a multidisciplinary team to continue this cutting edge research. Here she explains more about the work and why it's so important...

Flood basalt eruptions are one of the most hazardous volcanic scenarios in Iceland and have had enormous societal and economic consequences across the northern hemisphere. In 2012 the UK not only included an Icelandic flood basalt eruption in our National Risk Register but listed it as one of the highest priority risks. Such an eruption is hazardous not because of ash (for instance, Holuhraun is not producing any ash at all) but because of volcanic gases and aerosol which can cause air pollution and even impact the climate.

The air pollution from Holuhraun has been intense since the beginning, repeatedly reaching hazardous levels of SO2 gas in populated areas in Iceland. Moreover, elevated concentrations (albeit not at dangerous levels) have been detected in the UK and mainland Europe.

Holuhraun, Iceland, October 2014
The blue colour of the eruption plume is typical for sulphur-rich emissions
The available measurements from Holuhraun suggest that the sulphur emissions (per kg of erupted magma) may be exceeding both that of other recent eruptions in Iceland and perhaps also other historic basaltic eruptions globally, raising questions regarding the origin of these prodigious quantities of sulphur.

A lack of understanding of the source of this ‘prodigious’ sulphur, the conversion rates of SO2 gas into aerosol, the residence times of aerosol in the plume and the dependence of these on meteorological factors is limiting our confidence in the ability of atmospheric models to forecast gas and aerosol concentrations in the near- and far-field from Icelandic flood basalt eruptions.


Our project will contribute to two broad issues with sulphur:

  • The magmatic controls on the sulphur content of flood basalt eruptions. There is evidence to suggest we may have underestimated the sulphur output from older eruptions by several orders of magnitude.
  • The lifetime of sulphur in the atmosphere which is critical for both the magnitude and scale of the environmental perturbation.

We propose to address these questions both through petrological analysis of the erupted rocks, measurements of gases and aerosol in the volcanic plume, as well as plume dispersion modelling.

This project involves collaboration between a number of institutes in the UK (British Geological Survey, Universities of Cambridge, Oxford, Leeds, Birmingham and Manchester, and the UK Cabinet Office Civil Contingencies Secretariat) and Iceland (Icelandic Meteorological Office, University of Iceland and Icelandic Civil Protection). The first step is to plan some very challenging fieldwork in winter time Iceland (January 2015), and again in the summer if the eruption is still ongoing.

Evgenia

On Twitter follow Evgenia @EIlyinskaya and the BGS Volcanology team @BGSvolcanology

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