Bárðarbunga daily update 24-September-2014

This information is going to get outdated quickly.

Current status in Bárðarbunga volcano at 21:47 UTC

  • Eruption in Holuhraun continues at the same phase as yesterday. There is however just one or two crater erupting at the moment. New crater might open without warning if anything changes.
  • The lava field is now around 40 square km in size. It is now second largest lava field in Iceland at the moment. Largest lava field did come from Hekla volcano in 1947 in 13 month long eruption. It is expected if anything changes that Holuhraun lava field is going to reach 80 square km size in about two weeks (or one and a half) time.
  • Largest earthquake since midnight had the magnitude 5,2. Other earthquakes today have been smaller in magnitude.
  • Bárðarbunga caldera continues to subside around 50cm/day. Total subside is now around 27 meters.
  • The lava field is going over a path that has been used by geologist to get to the eruption. The path in question is called Gæsavatnaleið. At last check that lava field had around 200 meters until it was going to go over the road and close it permanently.
  • Earthquake activity is increasing in the dyke. This suggest that pressure is increasing inside the dyke. This also means there is high risk of an eruption in new location in the dyke, inducing under the glacier with everything that follows it (glacier flood, volcano ash and so on).
  • If eruption happens under the glacier the harmonic tremor is going to jump up and glacier flood is going to be visible soon after that. Depending on where the water is flowing under the glacier.
  • No major change has taken place today.

Other things

I am sorry for this late update today. I got a hardware to watch Icelandic Television in Denmark over the internet (IPTV). But the video kept freezing and it took a while to figure that out. Turns out the problem is my current router, it just can’t handle the traffic. So I had to get a new router that did cost me 103,78€. The new router is going to solve this problem for good. The last router that I did buy did cost me 25€, I had to buy cheap router since I was broke at that time.

Article updated at 22:06 UTC. Corrected numbers about the lava field size.

149 Replies to “Bárðarbunga daily update 24-September-2014”

  1. Some of the quakes were felt in the town of Akureyri about 200 km to the northwest.

    It depends on the faults, if you would feel it and the fault direction (SWS – NEN) would not connect it to Jökulsárlón.

    BTW: When there, try the waffles with whipped cream and jam.
    And don’t forget to go on the boattrip!

  2. 2014-09-25
    16:35:19 UTC M4.2 ICELAND
    14min ago Depth:10 Km
    216 km E of Reykjavík, Iceland / pop: 113,906 / local time: 16:35:19.6 2014-09-25

    Not confirmed, on the YouTube live Mila feed watching the ongoing eruption can be scary enough but when you see a Death Star super imposed on the live feed it takes everything to a new level lol

  3. From today’s Smithsonian / USGS volcano listserv’s weekly summary:

    “During 17-23 September, IMO maintained Aviation Colour Code Orange due to continued activity at Bárdarbunga’s Holuhraun eruptive fissure. Chemical analysis and geophysical modeling indicated that the source of the magma was at a depth of more than 10 km. Persistent subsidence was detected from the Bárdarbunga caldera and crustal movements signified that the volume of magma in the dyke slightly increased. On 21 September the lava field measured 37 square kilometers. Field scientists estimated that about 90% of the sulfur dioxide gas from the eruption originated at the active craters and the rest rose from the lava field. Dead birds were also found around the eruption site. A report on 22 September noted that the total volume of the erupted lava was 0.4-0.6 cubic kilometers and the flow rate was 250-350 cubic meters per second. Persistent subsidence was detected from the Bárdarbunga caldera; the volume of the depression was an estimated 0.6 cubic kilometers on 23 September.”

  4. Might it be possible that the caldera is subsiding in steps, but that the more gradual drop in height being measured by the Bardarbunga GPS is due to melting ice at the base of the glacier? The melting caused by a small eruption / gentle heat.

    Glacial ice is full of trapped air pockets, so is less dense than pure ice. So when glacial ice melts it will take up much less volume as its liquid equivalent.

  5. Also bear in mind that water trapped under a sheet of ice will behave very differently to water that is ponder and exposed to the atmosphere. The pressure exerted by the ice could cause the underlying water to flow up and over geographic features that ponded water would be held back by.

    This could make a jokulhaup flood out in unexpected places.

  6. Some clarification. Airborne radioechosounding is the standard technique for mapping the bedrock surface under the much thicker Antarctic and Greenland icesheets, so it can certainly detect the floor of the BB caldera. Glacial ice deforms quasi-plastically under pressure. Even though there may be water at the bed, the interior of the ice mass in the caldera is not going to be full of air or water-filled cavities. The annual melt season must be finishing around now, so the ice surface is highly unlikely to be lowering by around 0.5m/day due to surface melt, especially at around 2000m elevation. And the depression in the ice surface is bowl-shaped, so its volume is very substantially overestimated by multiplying caldera area by maximum surface lowering. None of this helps to explain why the caldera floor is sinking, however!

      1. Where has all that volume gone? Meltwater? Or has it turned to steam and blown out of the Holuhraun fissure? There is a lot more steam above the that fissure than I would expect from basaltic lava.

      2. It has not gone anywhere. The shape of the rock has changed and the glacier is falling with it.

        If there was a void in the caldera roof allowing water to reach the magma chamber, you would know about it. Otherwise, the caldera is impermeable and water is incompressible.

        What is going on with the glacier volume is by far the easiest side of this puzzle.

  7. Radio wave reflection is dependent on dielectric characteristics which are different each for water, ice and acid which you would expect to form with the very sulphur laden gases from an eruption. Any changed state at the boundary would show up on the reflections of tbe radio signals. This is how eruptions under ice can be detected. There is no evidence of an eruption in the caldera. Lookup Radio glaciology on wikipedia.

  8. LocoMoco said: September 25, 2014 at 19:17
    From today’s Smithsonian / USGS volcano listserv’s weekly summary:
    “… On 21 September the lava field measured 37 square kilometers… A report on 22 September noted that the total volume of the erupted lava was 0.4-0.6 cubic kilometers and the flow rate was 250-350 cubic meters per second… ”
    Anyone knows if it’s possible to define an estimate of VEI for the present BB eruption based on the above information only? Thanks.

    1. VEI doesn’t apply here (see above). It’s just for explosive eruptions. This has been discussed before.

    2. VEI 0 or VEI 1.

      Because eruption is non-explosive.

      But I know what you want to know. Eyjafjalljokull, VEI4 was 0.3km2 of tephra in a month. Grimsvotn, VEI4 was 0.8 km3 of tephra in 3 days. Krafla rifting fires, VEI0, was 0.3km3 of lava in 10 years. Laki was VEI4 (explosive-wise) but 15km3 of lava in 6 months. Even better, Trolladyngja was VEI0, but 45km3 over several years to even several decades.

  9. @Pochas,
    a glacier is not just a sheet of ice or just a frozen lump of water, it is a dynamic system that has a LOT of energy in it on its own.


    There are tremendous forces at work inside the glacier alone, in this case there is a volcano waking up underneath a HUGE glacier. Just imagine the shear power that will be released when the caldera collapses, the energy of the combined systems will be released at the same time.

    Just imagine the tonnes and tonnes of ice, compressed and pulled on very heavily by gravity, on top of a volcano that is just about ready to collaps on itself. I really understand why they are monitoring and worrying so much at the moment.

    Now about the GPS measurements, for an event occuring in the mountain, underneath the glacier, causing the sudden drops and rises at the surface (Where the measuring devices are.) it would take something like the energy that would be released when all the stones from Stonehenge would be doing summersaults and backflips on top of the caldera. My educated guess on why the sudden drops and rises occur is: the glacier responding to the shockwaves of the earthquakes/movements of the ice and adjusting itself back to equilibrium. A glacier is under a tremendous amount of stress on its own, a volcano having hiccups underneath it will cause a lot of extra stress.

    It is absolutely true that the sinking motion is caused by the slow collaps of Bardarbunga, the adjustments the glacier makes to itself are in my opinion the reason of the relatively sharp falls and rises on the GPS measurements, in other words, the drop of roughly 50 to 80 centimetres a day is the collaps of the caldera and the drops and rises that occur during the day is the glacier adjusting itself.

  10. It is clearly evident that over the last couple of days the subsidence has started to slow down. It has now started to moved above the top moving trend line ,this is the first time since the chart started. It could revert back to the same drop per day, or there could be much larger falls or it might stop.
    I can only see a couple of reasons what may have caused this. and the main one is that magma is increasing in the chamber and thus slowing it’s subsidence.
    Looking at the EQ plot it looks like they are moving outwards I would think this is the magma looking for the emergency exit. the big question is what happens if it find one.

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