When the next eruption begins in the Reykjanes peninsula, there may be precious little time to react, according to the latest report from the Icelandic Met Office on the matter.
Magma filling fast
The Met Office notes that, as in previous eruptions, magma is gathering in great volume beneath Svartsengi. As of February 22nd, it is estimated that there are some 5 million cubic metres of magma recharged into the reservoir beneath Svartsengi.
“Considering the trend observed prior to previous volcanic eruptions in the Sundhnúkur crater row, the likelihood of an eruption is very high once the volume reaches between 8-13 million cubic meters (derived from joint InSAR-GNSS models),” the report states. “Based on the results of the model calculations, this could occur early next week if magma accumulation continues at the current rate.”
They emphasise, however, that “there is a degree of uncertainty in this interpretation, and it cannot be assumed that the behaviour will be identical to the past eruptions here.” At the same time, the magma system itself may evolve in such a way that it may take even less magma than before for an eruption to occur.
Three likely scenarios
The Met Office outlines three possible scenarios:
An incident similar to the eruptions of February 8th and last December 18th, wherein sudden and intense earthquakes followed by an eruption between the mountains of Sýlingarfell and Stóra-Skógfell. This would give a warning time of thirty minutes or even less.
The second scenario would be similar to the January 14th incident, wherein there is an eruption by Hagafell with lava flow reaching the barriers around Grindavík within an hour. This would give a warning time of approximately one to three hours.
The third scenario would be the worst case scenario for Grindavík–an eruption within the town itself. There would be a warning time of one to five hours from the first earthquakes to the start of the eruption.
As always, every aspect of an eruption is notoriously difficult to predict with perfect accuracy. This is especially the case as what is happening beneath the surface of Reykjanes is fluid, quite literally, and although predictions can be made, they are subject to change.
“Please note that these scenarios are based on interpretations of the latest data and the observed development of the previous events at the Sundhnúkur crater row area,” the Met Office concludes. “Uncertainty must be accounted for in this interpretation, as it is only based on few events.”