Thursday, September 11, 2014

Bárðarbunga Eruption Continues With Potential For Caldera Collapse

This is a continuation of the main blog post about Bárðarbunga.

Bárðarbunga continues it's fissure eruption north of Vatnajökull in the 
Holuhraun lava field, and signs are indicating that the main caldera of Bárðarbunga is starting to collapse. If I haven't stated this before, that's going to be very bad news for Icelanders if it occurs, however, it's going to be a slow process that can take months. What could happen? Under the main caldera is a magma chamber. That chamber was cut by the magma dike that is feeding the fissure eruption to the north. This allowed magma which was previously stored in the large chamber to escape northward, potentially leaving a void in the chamber. 

Without all that magma to support the chamber ceiling with pressure, gravity takes its toll, and the volcanoes caldera walls begin to get sucked into the void. Once it fully collapses, tons of solid rock, ice, and melt water will come into direct contact with the magma at the bottom of the chamber, resulting in a very large explosion. This explosion will have high concentrations of ash, and gas, and could spur a week-long eruption similar in style to the Grimsvötn eruption, but on a larger scale. This absolutely would disrupt air traffic, and will result in massive flooding to the West of the caldera. 

Currently, there are no signs the eruption is stopping. IMO reports that they think the amount of lava being erupted by the fissure north of the Bárðarbunga caldera is probably equal or less than the amount of magma entering the dike and chamber, which means the system is STILL very much primed for more action, which at this point will probably occur. No less than seven eruptions (6 of them subglacial, and quite short lived) have been confirmed so far, so the entire region has a potential to spawn a new fissure at any time, and the slow subsidence of the Bárðarbunga caldera is very worrying.

Icelandic scientists will probably not sound this dire in their press releases, because if they sound the alarms and nothing happens, public trust erodes. I am in the 'better safe than sorry' crowd, myself, and would advise people to make plans to evacuate flood plains well in advance of this impending eruption. There are simply no signs right now that this eruption will be coming to an end any time soon, and the longer it goes, the greater the danger will be to those who have not prepared.


  1. Hi,

    with special permission I had the unique chance to photograph directly at the eruption – a few of my best pictures are online on my website:

    Kind regards,

    1. Excellent work Lukas! And what an awesome sight!


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