Eyjafjallajokull 2010: chronology of magmatic processes and their linkage to unrest signals and eruption behaviour

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The eruption of Eyjafjallajokull volcano in 2010 caused widespread disruption, travel chaos and economic damage across Europe, closing airports, stranding tourists and halting air freight. At least 13 major travel operators went bust in 2010, with the eruption being a significant contributing factor.Whilst many studies focus on the behaviour of ash when injected into the atmosphere, this project is concerned with the magma itself. The Eyjafjallajokull eruption followed over a decade of periodic unrest, with suspected magma movements beneath the volcano in 1994, 1996 and 1999. When it did erupt, the volcano produced a magma that was clearly a mixture of three components, an evolved, sticky magma and two different hot, basaltic magmas, which interacted with and heated up the evolved component so that it could be erupted. Crystals in the magma record the mixing event, by growing zones with different compositions. If the crystals sit in a hot magma chamber, they gradually reset towards a uniform composition. By looking at how far this resetting process has gone, we can determine how long it has been since the zones formed, and by inference, since the magmas mixed. Our initial work looking at these samples has shown that there are multiple mixing events, occurring up to 18 months before the eruption itself occurred. A major mixing event seen in many crystals correlates with the start of the summit eruption, and it is reasonable to expect that new mixing events - representing fresh magma input - would have a strong impact on the state of the eruption. This project will have two research strands, operating at Edinburgh and Leeds, with involvement of the British Geological Survey as a key stakeholder. The role of Edinburgh is to refine what we know about the character of the products, to identify the three mixing components and their properties such as temperature and water content. The role of Leeds is to determine the times at which the magmas have mixed before they erupt, and to then use this to show the series of events that happened in the magma chamber beneath the volcano, both before, and during, the eruption.With this data, we will be able to "date" the mixing events recorded in crystals from throughout the eruption deposit, looking for when magma pulses arrived into the magma chamber, and linking this to the eruptive activity as seen at the surface, as well as the signals that were recorded by the Icelandic scientists monitoring the eruption as it happened. We will then discuss our results with Icelandic colleagues in order to improve our model for the plumbing beneath the volcano, better understand the linkage between magma supply and eruption style and to better relate monitoring signals to magmatic processes.