Is Iceland’s next volcanic eruption about to happen? The Iceland Meteorological Office has increased the risk of an eruption at Bárðarbunga (or Bardarbunga) volcano, after hundreds of earthquakes were reported over the weekend. The risk level has been set to orange, which is the fourth-highest on a five-level scale. Dave McGarvie, a volcanologist at The Open University explains: We have known for some time that Bárðarbunga was going to do something. Because it is covered in ice, we rely on instruments to reveal its behaviour. The clues from the patterns of earthquakes and earth movements reveal two clusters where magma is moving towards the surface, and if it gets there it will erupt. But whether this will be a gentle or a violent eruption is still uncertain. There is no way to predict when the eruption may happen, but we should get a few hours notice. The good news for air travel is that both clusters are away from the heart of the main volcano which makes it less likely that an eruption will produce the fine ash that causes disruption. The worst-case scenario may be that this is the start of a major volcano-tectonic event at Bárðarbunga, which may further develop to the southwest. This is a concern because in the southwest there are fissures that have produced Iceland’s most voluminous lava flows, since the ice melted some 9,000 years ago. It is emphasised that it is not known yet whether this is an isolated event or the start of a more prolonged and larger volcano-tectonic episode. It may be years before we know for certain. But at some time in the future there will be a major fissure eruption to the southwest of Bárðarbunga – we just don’t know when. The Eyjafjallajökull 2010 eruption caused a lot of disruption to flights in Europe. However, old flight rules – avoid all ash – have been relaxed so aircraft can now fly when there is some (but not too much) ash in the sky and the Met Office revised its model that estimated ash concentrations in the atmosphere, so we now have more certainty about how much ash there is and where it is. The forecast is: No knowledgeable volcanologist worth their salt would ever suggest basing western Europe’s ash cloud mitigation plans on a repeat of Eyjafjallajökull 2010, because it is very unlikely. A short-lived but powerful injection of ash into the atmosphere like Grímsvötn 2011 is more typical. Image1: Subglacial Gjalp eruption in 1996. Oddur Sigurdsson, Iceland Geological Survey, CC BY Image 2: Bardarbunga caldera is about 10km wide in diameter. Iceland Geological Survey, CC BY https://theconversation/is-icelands-next-volcanic-eruption-about-to-happen-30642
Posted on: Mon, 18 Aug 2014 23:07:53 +0000
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