Krakatoa! East of Kilbride
by Keir Liddle
The Icelandic volcano Eyjafjallajokull has been erupting since the 25th of March, but this eruption only yesterday started to cause massive disruption both in Iceland and in the UK. Iceland is no stranger to volcanic activity: the island has 130 volcanoes, of which 18 have erupted since settlement of the island, and over the past 500 years the volcanoes of Iceland have accounted for 1/3 of total global lava output. This is no surprise, as the island is a volcanic hot-spot due to its position astride the edges of the Eurasian and North American plates.
Earlier today, I spoke with Dr. Thorvaldur Thordarson, Reader in Volcanology, from the University of Edinburgh’s school of Geo-Sciences about the eruption.
Dr Thordarson explained that the eruption in Iceland was caused by its positioning on the plate boundary, which makes Iceland particularly volcanically active. Beneath Iceland is a great plume that rises from great depths within the Earth, bringing extra material to the surface which melts en route and becomes molten rock or magma. Eruptions like the one currently taking part in Iceland have been seen before, and there have been two eruptions in a very short period of time there: one on the Eastern flanks which occured in an ice free region on the 20th of March, and the current eruption.
According to Dr Thordarson, the current eruption in Iceland is more powerful because it is taking place under an ice cap. Thus as the magma (at temperatures of around 1000 degrees) comes into contact with the ice it causes a lot of melting, and as the lava comes into contact with the water, it “super boils” it, causing an explosive expansion of steam which leads to more intensive explosions.
It is also anyone’s guess as to how long the eruption will last. Dr Thoradson noted that it is currently showing no signs of stopping, so that we are faced with one of two scenarios: if the eruption remains explosive, as it currently is, then it probably won’t last all that long. However, if there is a phase change in the eruption such that it becomes a more lava producing one, then it could last much longer as potential sustained activity might lead to more minor explosions, lasting for many more weeks.
Dr Thoradson also reported that it was unlikely that the eruption, as it stands, would have any significant effects on the weather or climate, as the eruption is far too small to be climatically significant. It would need a concentration of an element like sulphur, or a far higher volume of material escaping the volcano, to cause such a change. We might see some effects on the sunset or perhaps even a blue moon near to the volcano, but probably not further afield.
Although, Dr Thoradson was quick to point out that volcanoes are notoriously unpredictable, and did not fully discount the situation changing. He also noted that while it seems unlikely, in his view, that this eruption could trigger other eruptions in Iceland, the country does seem to be entering a period of increased volcanic activity. Judging on what we know of eruption history in Iceland, we can perhaps expect more eruptions of this or a similar scale.
It is also worth pointing out to all those who have been inconvenienced by the volcano’s eruption, with delayed flights and the like, that the volcano has caused flash floods by melting the glacier. These have caused significant damage to farmland in Iceland as well as to the main highway that circles the island. Which is far worse, in most cases perhaps, than a delayed flight and a night in a hotel.