Tuesday, November 4, 2014

Bardarbunga Volcano Largest Eruption In Iceland In Over 200 Years

Bárðarbunga volcano in Iceland is defying expectations and is producing so much lava, it is now the second largest eruption in Iceland's history, after the 1783 eruption of Laki, which erupted for over 8 months. The current fissure eruption, which many volcanologists and bloggers like myself believe to be a precursor the main event, has now produced nearly 100 square kilometers of lava, and the gas being emitted is definitely beginning to cause problems for Icelanders, much like the Laki eruption.

Bárðarbunga volcano is a caldera and fissure system, which can be, and is, a potentially deadly combination.

Since my last blog post on the subject, not a whole lot has changed, except now some predictions such as caldera subsidence, jökullhlaups (glacier outburst floods), and massive amounts of SO2 being emitted are starting to come to fruition.

The main caldera of Bárðarbunga continues to subside at a steady rate of around 40-50cm a day, and it is showing at the caldera rim. A large 'cauldron' where the ice-covered caldera lies is clearly visible now during overflights. Other smaller 'cauldrons' are appearing near the rim as well, as heat from magma getting close to the surface warms the rock. The latest report on the caldera is saying around 2 cubic meters per second of ice is being melted (that's a lot), and they are expecting drainage at any time.

The biggest danger to people right now is twofold. The SO2 gas can and does cause lots of breathing issues, especially for people with asthma, and the elderly. People are advised to stay indoors if they encounter poor air quality, as SO2 can easily damage the alveoli in your lungs, causing permanent damage. The other threat is that of jökullhlaups, glacier flooding, which occurs when a large pocket of water is generated within a glacier, causing the temperature difference to eventually rupture out of the ice wall with near explosive force. This can happen at any time, and has caused massive damage to property and infrastructure from much smaller volcanoes.

The current situation at Bárðarbunga is getting more and more dangerous as the fissure eruption progresses. The worst case scneario right now is if the caldera continues to subside, with ice and rock eventually coming into contact with the magma conduit, which would result in not only flooding, but a very explosive eruption, much larger than that of Eyjafjallajökull, or Grimsvötn (Grimsnes). If I were to estimate the scale of the eruption, it would likely be around a VEI 3-5 event, depending on the internal mechanics.

However at this time, the eruption remains stable. Since the fissure has opened, it has consistently maintained its flow, and seismicity has decreased. This means that currently, as much magma is flowing into the dike intrusion as is being erupted as lava onto the Holhuraun lava field. If the fissure stops erupting and magma flow remains steady, it is anyone's guess as to what could occur. One possibility is that the eruption ceases altogether, which is unlikely. Another is that other fissures will open when the magma finds another route to the surface. Another is that the caldera of Bárðarbunga inflates, and an eruption occurs due to changes in caldera structure which will now have more fractures and avenues for the magma to reach the caldera.

Really, nobody knows for sure where this is going, but one thing is certain, this is a whopper of an eruption for Iceland, and is truly fascinating. FUTUREVOLC, a project which is using Iceland as a laboratory to study volcanic mechanisms is practically thrilled with the data they're able to be collecting, and Iceland itself does see an uptick in tourism. Many are braving the harsh conditions and risk of gas exposure to capture photo and video of the volcano (I'm fine right here watching the webcam), which can be risky. Earlier in the eruption, a billionaire from Europe defied orders by Iceland to stay away from the eruption site, to visit the volcano and take a 'selfie'. Believe me, this was an incredibly dangerous and stupid stunt, as any wind change could have killed the whole group.

There truly is not a whole lot else to report until something else changes with Bárðarbunga. But I did want to give a quick catch up and synopsis of what's going on there. 

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