The word on the street in Reykjavík
I’m in the Reykjavík this week on fieldwork. People here have been following developments at Bárðarbunga since the earthquakes began on Saturday. The word on the street is wait and see.
The story is on the radio and in the papers, but it remains the same: lots of earthquakes, some quite large, but no sign of them moving towards the surface.
The Civil Protection Agency have evacuated the highland areas to the north of Bárðarbunga. If an eruption happens beneath the glacier, then it is likely that a flood will travel in this direction and could destroy the roads. In technology-loving Iceland, you can still get mobile phone signal in this remote region, so they identified all the phones in the area and sent them SMS messages to let them know that the region was closed.
This afternoon (Wednesday), the Coastguard plane is flying over the region to map the glacier. This will be a reference to make it easier to see changes. It is using the same radar that brought you the famous ‘Scream’ image of Eyjafjallajökull. If an eruption begins beneath ice, a depression will form on the surface of the glacier as it melts at the base. I expect that they will release results form this later.
What’s going to happen?
The best answer to this is no-one knows.
There is a reasonable chance that the answer will be nothing. The earthquakes continue, and their source seems to be extending towards the NE at a depth of 5-12 km. This is rifting; North America and Europe continuing their continental drift apart. GPS data show that magma is filling the gap. Many rifting events do not produce an eruption and the earthquakes simply settle down.
If the earthquakes move to the surface then the most likely outcome is an eruption of basalt. If the cracks reach the surface under ice, then this can be explosive, if it reaches the surface outside the glacier then we can expect lava. Dave McGarvie has a more detailed discussion of scenarios here. Some news reports focus on some much larger eruptions in Bárðarbunga’s history where rifting extended far in the opposite direction (to the SW) through the Veiðivötn region, but these are worst-case scenarios and are much less likely.
There is a lot of information available from official sources in Iceland. The three main ones are below:
There is also many blogs covering the unrest and lots of interesting discussion on Twitter. In particular, the Bardarbunga list list compiled by @gislio has many key contacts and links to interesting articles.
Some background reading
I’ve written lots of posts about Iceland volcanoes and ash clouds. The earthquake swarm could continue for some time. Here are a selection that you can read while we wait and become an instant Iceland expert.
- Sounds of the Underground: Much of our information about what goes on beneath volcanoes comes from study of volcanic earthquakes. This post lets you ‘hear’ what they are like.
- Why people are scared of Katla: A major hazard in Iceland from subglacial eruptions is the flooding and Katla is a notorious example.
- Gas, not ice, makes subglacial rhyolite explode: This post explains what makes an eruption produce ash (explosive) or lava (effusive) and how glaciers can affect this.
- UK ash deposition from Grímsvötn 2011 eruption: The most recent eruption in Iceland deposited ash in the UK. This post explains how citizen scientist volunteers helped map where it fell.
- A history of ash clouds and aviation: Every Icelandic eruption since 2000 has affected air travel, but not all cause serious problems.
- Do Iceland’s volcanoes pose a threat to the UK?: Video of a lecture that I gave recently at the Geographical Association Annual Conference.