Large-magnitude fissure eruptions in Iceland

Laki eruption scenario

Aerial photograph showing the crater row where the Laki fissure eruption took place. Photograph by Oddur Sigurdsson, copyright of Iceland Meteorological Office.

Report on the source characteristics of a Laki-type eruption for scenario modelling and findings of an expert consultation and elicitation

The BGS and the UK Meteorological Office are working with government departments, agencies and academic partners across the UK and Iceland, to ensure that plans are in place in Iceland, the UK and the rest of Europe to respond to future Icelandic volcanic eruptions.


During the Eyjafjallajökull eruption in 2010, a Scientific Advisory Group in Emergencies (SAGE) was set up.

One of the tasks of the SAGE was to consider potential future eruption scenarios that might affect the UK.

One of the eruption scenarios adopted in the UK National Risk Register (NNR) is based on the 1783–84 fissure eruption of Grímsvötn volcano, commonly known as the Laki eruption.

The Laki eruption had significant impacts across Europe, and devastating impacts on Iceland: more than 60% of the grazing livestock was killed by fluorosis and ultimately 22% of Iceland's population died as a result of induced illness, environmental stress and famine (Thordarson and Self, 1993 and 2003).

Understanding eruption impacts

The BGS was contracted by the Cabinet Office Civil Contingencies Secretariat (CCS) to characterise the source parameters (e.g. the height of eruption column, the rate of emission, the distribution of particles etc.) and their uncertainties needed to model a Laki eruption scenario, i.e. the atmospheric dispersal of eruptive gases and aerosols. This is critical to better understand the possible impacts of such an eruption.

In order to do this, a meeting was held in May 2012 which included an expert elicitation, deliberative discussions and consideration of the existing literature.

A multidisciplinary expert group with specialist knowledge of this particular type of eruption; eruption dynamics, volcanic degassing, remote sensing of gases and aerosols, atmospheric processes and dispersion modelling; was nominated to take part, along with experts on health and environmental impacts of volcanic eruptions to provide guidance on their modelling requirements.

Scenario characterisation report

The report, Large‐magnitude fissure eruptions in Iceland: source characterisation, presents the outcomes of the meeting, the preliminary uncertainties on source term parameters identified as a result of the elicitation, a monitoring discussion and contains references for key research papers.

Areas where our scientific understanding is limited or still emerging are highlighted as 'knowledge gaps', and research to tackle these gaps is therefore recommended.


Thordarson, T, and Self, S.  1993.  The Laki (Skaftár Fires) and Grímsvötn eruptions in 1783–1785.  Bulletin of Volcanology, 55, p233–225.

Thordarson, T, and Self, S.  2003.  Atmospheric and environmental effects of the 1783–1784 Laki eruption: a review and reassessment. Journal of Geophysical Research, 108, D1.


Contact Dr Sue Loughlin or Dr Charlotte Vye-Brown for more information