Azalean Overlords and Reader Participation Invitational

Azaleas at Bellingrath Gardens Photo: Wikimedia Commons

This was originally going to be my Ruminarian VIII, but since the whole topic of stratospheric SO2 has been previously covered, I kept it short.  If ya want to call it Ruminarian VIIa, I’m okay with that.  This one is simply kicking around the potential SO2 of the current eruption.

Throughout Earth’s history, there has always been a “dominant” species. This is typically the species that is best suited to exploit the available resources and either has no predator, or has eliminated/nullified its predators and/or optimized itself to use what resources are available to it.   In some cases, over specialization has made it vulnerable to changes in it’s environment, and due to subtle shift in that environment, becomes wiped out. (Typically this is due to the unfortunate convergence of two or more species wide devastating events.)   For example, the ongoing Deccan trap eruption coupled with the untimely arrival of a large asteroid at a nearly antipodal position on the Earth. Hello K-T boundary.

There are a few posters here on VolcanoCafe that firmly believe that the Holuhraun eruption will culminate in a new shield volcano. Their reasoning is quite sound, though a few others have alternate opinions about what the end result will be. Supposing that the final magma effusion is on the order of 2 cubic km, with a bit of poking at the data we can get a ballpark figure for what sort of SO2 emission will accompany that. The publication “Preservation of Random Megascale Events on Mars and Earth, Influence on Geologic History.” (edited by Mary G. Chapman) contains a paper by Thordarson et al titled “Effects of megascale eruptions on Earth and Mars” (2009). Figure 6 from that publication presents a graphic representing sulfur content of magma vs the TiO2 to FeO ratio. Cycling that through Dplot and determining the formulaic relationship for fully degassed magma, then running that on the Holuhran geochemical data, I get a value of around 200 ppm by mass for the sulfur release. The resulting SO2 mass is approximately 2 x the mass of the released sulfur. (Oxygen’s standard atomic weight is 15.999, Sulfur is 32.06.)   Assuming that the magma from Holuhraun is basalt, it’s mass is about 3100 kg/m³. 2 km³ is 2 x 10^9 m³. Multiplied by the mass, you get 6.20E+12 kg. This would equate to about 1.24E+09 kg of sulfur, or 2.48E+09 kg of SO2. Or 2.48 million metric tones.

That may look big, but reportedly the really large scale events of 1000 km³ or so emit in the range of 5 to 10 gigatonnes. From researching a previous post, I discovered that the sulfate from a stratospheric SO2 injection can linger for around 50 months. So far, the plume from Holuraun hasn’t come anywhere near reaching the stratosphere, and has been a purely troposphere affecting event. In the troposphere, the SO2 is churned around in the relatively turbulent air (the troposphere contains all “weather”) and the moisture acts to leech the SO2 out at a much higher rate than the stratosphere.   Yes, there will be more acidic rains due to it, but it will not linger long enough to really affect the climate.   Many years ago, I moved a plant from one part of my yard to another.   Concerned about what the plant needed to thrive, I found out that Azaleas love acidic, well drained soil. In the grand scheme of things, this means that any Holuraun SO2 that doesn’t burn the leaves, should make them healthier, giving the roots a more favorable soil. Will they go on to become the dominant species? Beats me, but to be safe, let’s just be nice to our future Azalean overlords.  Keep em watered and they may in turn keep thee!

ESTIMATED SO2 release based on the 95% conf range of the geochem data verses fully degassed magma total volume.

On behalf of our Future Azalean Overlords,




Reader-participation article, invitation for YOUR contributions!

The eruptive plume and the lava stream 20 November 2014 at 5PM. Pulsating activity; every 10-15 minutes an explosion in the crater was followed by a gush of magma down the lava stream with splashes to either side. Photo: Ármann Höskuldsson.

The eruptive plume and the lava stream 20 November 2014 at 5PM. Pulsating activity; every 10-15 minutes an explosion in the crater was followed by a gush of magma down the lava stream with splashes to either side. Photo: Ármann Höskuldsson.

One of the delights of reading the comments section are the many scenarios, ideas and interpretations our readers come up with. As there is merit to most of them, Dragon Kilgharrah has decided that she will collect your entries and select the most interesting and intriguing of those for next Friday’s VC article. In order not to inundate Kilgharrah with a flood of papers a million words or more and in order to give her a chance to sort through your contributions, please try and keep within these limits:

  • Your proposal should be no more than 500 words long and supported by no more than two graphic representations or pictures
  • You email your entry to who will pass it on to Kilgharrah in the Den
  • Wednesday 24.00 UT/GMT is the deadline
Thermal images (FLIR) of the craters, seen from the west (hence N to the left and S to the right). The image on the left was taken on 18 November 2014 at 16:00. Thermal convection is greatest from the northern part, Heimasæta, and the temperature is somewhere in the range 1147-1188°C. The image on the right was taken 23 October 2014 when craters Baugur and Heimasæta were both active. (IMO & Institute of Earth Sciences, information from the field group.)

Thermal images (FLIR) of the craters, seen from the west (hence N to the left and S to the right). The image on the left was taken on 18 November 2014 at 16:00. Thermal convection is greatest from the northern part, Heimasæta, and the temperature is somewhere in the range 1147-1188°C. The image on the right was taken 23 October 2014 when craters Baugur and Heimasæta were both active. (IMO & Institute of Earth Sciences, information from the field group.)

Be creative in your thinking but not “too creative”! Your idea of what will happen should ideally be within the realms of the possible, so perhaps a few reminders are in place:

  • We are dealing with a very large volcanic system, known to have set off large eruptions at great distances from the main vent such as the Torfájökull eruption of 1477 and the Veidivötn eruption of 1480. Bardarbunga is situated where the Mid-Atlantic Ridge splits the North American and Eurasian continental plates and directly above the centre of the inferred Icelandic Hot Spot.
  • The Holuhraun eruption is fed by magma from the reservoirs of Bardarbunga. In spite of Ármann Höskuldsson being (mis-)quoted as saying that the temperature is some “200°C higher” for a basaltic eruption, the 1147-1188°C as measured at the vent is actually some 100 – 200°C lower than it would be if it was juvenile magma direct from the mantle. Also, the chemical composition is such that it has sat for a while, cooling and begun to fractionate.
  • The crust is considered to be up to 40 km thick even if it is suspected that it is much thinner directly underneath Bardarbunga, perhaps no more than 20 km. Thus the Holuhraun while forming a shield is not yet a shield volcano in the making as it has no independent supply of magma. In order to do that, it must break through to a depth of some 30 – 40 kilometres and this far, the deepest nearby quakes have been placed at 22.5 km.
  • The total amount of seismic energy released in the form of earthquakes, to date in excess of 400 TJ, TeraJoules (1 TJ = 1,000,000,000,000 joules), is equal to a single magnitude 6.5 earthquake such as the Eureka earthquake (California, USA), 2010. In spite of the awe-inspiring number of earthquakes greater than magnitude 3.0, even in spite of the very great number of magnitude 5.0 to 5.7 earthquakes (1,000 to 10,000 times more powerful than a “mere” M 3.0), remember that we are dealing with the movement of so many tens of thousands of cubic kilometres of bedrock that it truly boggles the mind.
  • The subsidence of the caldera is real. It cannot be explained by loss of volume due to melting ice as the energy requirement for such a glacial melting would be enough for at the very least a M 10.5 earthquake or roughly 1,000,000 greater than the cumulative seismic moment for the entire Bardarbunga crisis!
Animation showing earthquake focal points since September by VC reader Thomas Andersson

Animation showing earthquake focal points since September by VC reader Thomas Andersson

Hopefully, we will all have a very interesting read come Friday and who knows? Amongst those may be one contribution that predicts and explain the exact course of events! If all goes well, on Sunday November 30th, Carl will as promised give us his analysis of “What is going on at Bardarbunga”. So sharpen your brains and break out those plots!

Please remember the Wednesday November 26th deadline!

Pyrite & Kilgharrah


707 thoughts on “Azalean Overlords and Reader Participation Invitational

  1. Just a question, what do you think about these small but very deep EQs yesterday? The one under the dike have just been verified last hour. It seems to be just at the limit of the mantle for the 2 deepest ones… Magma coming directly from it? (IMO data)

    25.11.2014 01:43:03 64.818 -16.902 26.9 km 1.3 99.0 15.1 km ENE of Kistufell
    25.11.2014 01:08:23 64.758 -17.594 39.2 km 1.4 81.15 13.4 km NNW of Bárðarbunga
    24.11.2014 23:47:55 64.735 -17.518 16.5 km 1.1 99.0 10.5 km N of Bárðarbunga

    • My first reaction is: why did IMO not manually process the second quake in your list (along with some other big quakes that happened that day)? My second reaction is that the two verified quakes (first and last in your list) are outside Bárðarbunga and extremely small so they’re probably just the crust settling in a more comfy position and nothing much else.

  2. Verified earthquakes over the past 48 hours. All with mag > 1.5 are at or above 10km. I’m pretty sure this has happened before, but a week ago there was a strong column all the way down to 13 km. (Just reporting, not interpreting.)

    • I think the vertical scale on the graph has been extended downwards, to 40km now, on the site (to cater for the deeper earthquakes that are occuring).


    We have strong reason to suspect that SO2 output at Holuhraun is significantly lower. Thus I suspect we will see the end of eruption in soon, perhaps just a few more weeks at weak level.

    In Sept and October, it didn’t matter wind direction or speed, storm or calm, high or low pressure, one area downwind in Iceland would always suffer from severe pollution. Now it has been 2 weeks, we had all wind directions, high and low winds and no SO2 pollution anywhere.

    For me, this is a sign that magma has now fully degased (clearly much less SO2 released at Holuhraun), and this fits well with the observation of a much lower eruption rate and of a pulsating nature. Like Jon Frimann, I am thinking this eruption could be approaching its end.

          • Leslie, I think that decreased SO2 rate for the past 2 weeks is a sign that eruption is coming to an end…
            Degassed magma?

            • I wasn’t addressing the SO2 part of what you said, because I have completely no experience / knowledge in that area. … I’m not trying to be picky with you, just following my own (often non-linear) thought processes.

            • My logic in the the chuffing is from watching steam whistles that have piping mostly filled with condensate (water) trying to clear a path. The fun part is watching underway watch standers on the flying bridge scrambling for cover as this nasty rusty water comes spewing out. It’s pretty much a larger version of the classic “water hammer” effect where an acoustic wave propagates around the piping.,, potentially bursting a pipe. It only stands to reason that a similar hammer effect can be at play in a magmatic system, though logically, when a portion of the system fails from the overpressure, you get a new magma pathway. The interesting bit is will it finally pop a seam along one of the ring faults back at the main caldera?

            • The hammer effect? No. Just a large amount of moving mass that suddenly becomes blocked. Inertia provides the overpressure that is then distributed throughout the medium as a compression wave. (and sound is a compression wave, which is why you can hear it so readily when your plumbing system goes into oscillation with a train of hammers running back and forth through your pipes.)

              One cubic meter of basalt moving at 10 m/s carries about 155,000 Joules of kinetic energy. (lest I horked the math)

      • Dunno how good that may be. If the chuffing is what I think it means, then the whole system is being subjected to transient pressure pulses, one of which could hammer open a new pathway.

        • But eruption now releases very low SO2, compared to 3 weeks ago, This low SO2 has been since 2 weeks.
          What do you think of that? Magma fully degassed?

          • Could you expand on the “magma degassed?” question/comment please. The way you are asking makes a newbie like me, feel like I am missing something obvious here.

            Are you talking less gas in the magma coming from the ground? Or that the amount of gas coming out of the magma already above ground has dropped? Or have I completely missed your point?

        • I’ve said it before but it’s like a firework that getting near the bottom of the tube. I used to make them years ago and when you have a tube that’s choking itself with its own solid by products in the neck of the tube it goes into that un-nerving pulse that makes you think it’s going to self destruct, which I have seen them do.

          Not a realistic comparison I know, but the best explanation I’ve got is that harder material within the magma is choking the vent by deposition, increasing pressure. Probably deepening of the lava lake is causing some back pressure and the magma under greater pressure the a smaller aperture keeps forcing it out of the way periodically.

          I’m sure it will close up this vent in the near future. Then we will have the pressure building again in the system.

          • Probably more realistic than you think. Probably a combination of the two ideas, though pressure from the gas release is probably quite a bit less than the sudden pressure change due to choking back the momentum of several tonnes of moving magma.

            That lake is a good point, I had forgotten about that.

  4. This is one of my favourite pieces of music from my childhood. As I recall, I used to dance around the room to it, including over the furniture! 🙂 As you’ll appreciate, it’s notoriously difficult to play.

  5. I hope you all also keep checking George Vittons very nice blog. He has good connection and very often the latest news.
    He points the attention to Fogo, Popocatepetl and Pavlov in his article from yesterday.
    You could also watch El Popo through this cam:
    and of corse Graniya also has El Popo in her cam collection!

    • That’s the most amazing photo – but look at the shape of the cone: higher on the right of the picture than the left – I think it was taken from the west side of Nornahraun. You can see the edge of the lava very clearly and its reflection in the water around that edge.

  6. Irpsit mentioned last night the lack of SO2 reaching areas of habitation, and this morning we have what must be the thinnest column of vapour rising from the vent, since the eruption began.
    Is the eruption decreasing or is it just pausing for “breath”?
    There still seems to be plenty of movement in the lava in the cone.

  7. I have been watching the pulsing on Mila cam 2 about 50 minutes just now and kept notes when a new pulse started.

    A new pulse starts every 6,5 – 7,5 minutes. It lasts about 2,5 minute quite intense, the blobbing lava can be seen clearly then. After about 2,5 minutes the blobbing isn’t visible anymore and it takes about 4 – 5 minute before a new pulse starts. 🙂

  8. Note from the Den

    Dear all – apologies to anyone who may have seen a wonderful post about Alaska come up briefly on the site this afternoon, and then disappear again. Just a case of an eager little mouse inadvertently clicking on buttons that weren’t ready to be pressed! Naughty mouse!!

    Fear not, the post (and it’s a beaut!) will be published in due course.

  9. I find it quite surprising that the main lava flow still seems to be running SSE when all the mapping indicates that is almost going uphill.
    Maybe the north flank flow will start to move more quickly as it comes east, and encourage a change of direction. 😉

    • It certainly appears to be moving north now. Though I’m quite happy for it to go south – I’d like to see what happens when a lava flow meets the glacier…

    • People have been setting up GPS devices (on Kverkfjoll I think). See Univ. of Iceland facebook –

    • Forgot to add

      Preliminary analyzed data by the SIL seismic monitoring group of the Icelandic Meteorological Office up to Nov 27th

    • Ian’s plot raises the question whether the average depth of the earthquakes is changing. It probably depends on which size earthquakes you select. The M3.5+ above may show some deepening over time. For the M3+, I find little evidence. Below is a plot of the average depth, per week, of those quakes, in red. In blue is the same but weighted by the energy. The red is constant at 6 km (perhaps a small downward drift is possible). The blue is flat, and a little less deep at 5 km. (The difference indicates that the larger earthquakes are on average a bit less deep).

      • GPS looking interesting in the Grimsfjall area – large movement westwards from yesterday..

        The GPS don’t seem to have been moving a great deal recently, until I saw this.

        • Weird. Grimsvotn moves towards rift. Also THOC, GJAC; KIDC move towards rifting.

          In Grimsvotn maybe magma is arriving south/southeast of it. Me and Carl had said this in the past.

            • Thanks Ursula, I don’t know how you did that, but first the movement lines weren’t there, then they were, then they weren’t again; I don’t know what’s going on but it was good while it lasted!

            • Look at HAFS, VONC, GJAC, and DYNC.

              Four stations, all close to Bárðarbunga, all moving significantly, *at roughly 90 degrees to each other*.

              The caldera is being pushed and pulled and every way at once – and *twisted*. No wonder the poor thing is sinking and shaking! I don’t think it’s *necessary* to invoke too much in the way of magma to explain it. Not saying magma isn’t involved, but just keep that regional stress field in mind.

              I’d like to see a bigger map, showing the same data for (hypothetical, possibly nonexistent) GPS stations NE and NW of Herðubreið, and southwest down the rift beyond Hamarinn towards Veiðivötn; do we *know* for sure there aren’t significant movements at the further ends of the system?

            • Odd, I was under the impression that BB was on the mar and was under extension (as against compression). However with vonc and gfum closing it looks like it is getting squeezed. This makes the movement downwards if the caldera, with the inverted cone, more understandable as its being forced down by the compression. This also makes it more sensible why any reservoir at some depth (ie containing relatively unevolved magma) might be being extruded at Holuhraun. I can’t believe I haven’t spotted this before (not to mention everyone else) so I am hesitant to post. Have I missed something?

              Heeeelp, what am I missing?

          • “maybe magma is arriving”

            Or, the recharged magma that has come in over the years is also getting drained by Holuhraun. Remember Bardabunga’s dike entered the Grimsvotn swarm and hung a left. This could indicate that it made contact with one of Grimsvotn’s chambers. The collective thought at the time was that it turned away due to the greater pressure at the Grimsvotn end of the swarm as it passed by.

        • Often such large movement by a single station is followed by movement in about the opposit direction. At least that did happen few times already. Curious if that will be the case tomorrow also…

          I wonder if these single station movements are some kind of ‘error’ readings, caused by ….?

          • The stations do indeed move back and forth in usually small amounts on an almost daily basis. Sometimes there is a period of some days of more progressive movement, as there was in a spectacular way in late August when the rifting was underway. Also about a week ago some of the stations moved away from the rift for a day or two, about the time the Holuhraun eruption appeared to get more intense, but most of the time they just seem to move a little, and randomly. I guess if they moved toward each other, across the rift, it would squeeze it shut and choke off the eruption?

            • I was thinking of some particular dates EchoohcE and looked it up at .

              ie GFUM at the dates movingnorth and south, GJAC moving in opposite directions too.

              or at several stations on the dates
              moving ‘there & back’

              Some more examples can be found.

              I think to totals of the movement mainly were caused by the initial rifting event in the beginning of the event.
              Are there data available of the movement par day (numbers, not maps)? Would be fun to see movement per week, since the beginning … 🙂

            • Yes I keep looking at that linked site Rob, it’s fascinating but a tad annoying when it keeps refreshing every couple of minutes and you lose your position! A lot of data to take in; there must be a more brain-friendly way of looking at it. What we need is a graphics genius to sort it out… anyone? 🙂

            • The experts have been telling us for some time now that this GPS array is to measure crustal movements rather than tectonic plate movements. This is how they have determined where the magma has been moving and in what volume.

            • Not going to happen. The rift opened due to the plates moving apart. The GPS’s moving together are moving because of deflation: Magma is moving out of Bardarbunga, thus they are relaxing towards each other as the magma pressure, that held the caldera up, subsides.

  10. RÚV news at 22:00 (radio)

    Bárðarbunga caldera has sunk 50m since the start.
    Magnús Tumi does not expect the eruption to end soon.

  11. Goooooodmorning from Barda!
    I’m awake now 🙂

    28.11.2014 06:14:02 64.670 -17.440 1.1 km 4.9 50.5 5.3 km NE of Bárðarbunga

    And that is only 50%, so unchecked.

    • Holuhraun from a new webcam .
      During daytime we can now see Bardarbunga volcano in the background.
      As soon as it is getting dark, we can see the waxing crescent moon enter the scene from the left.
      The fissure eruption is still going strong & the pulsating character of the eruption is clearly visible in this video
      Published on 27 Nov 2014 icelanderuptions

  12. Telur litlar líkur á gosi í Bárðarbungu 27.11.2014 23:28
    gurgled ……..but the message is understood
    The box in Bárðarbunga has sunk about 50 meters from the volcanic activity in the region began . Dean geophysicist considers unlikely eruption Bárðarbunga .

    Scientists from the Institute of Earth Sciences , University of Iceland flew over Bárðarbunga yesterday with equipment that measures how much of the ice box Bárðarbunga has sunk . According to the latest measurements peeling now sunk about 50 meters . Most likely, it is believed that erupted in the hollow lava continues .
    ” Yes, we must consider the likely results and today we got off the flight yesterday and they are telling us that we do not see any end to this . This is all very similar , ” says Magnus Tumi

    Another option is to bring up the fissure glacier but it is not as likely , says Magnus . ” Then the third option and that is that it replaced the soda Bárðarbunga itself and it is unlikely most of this . ”

    About 130 cubic meters of magma flow before Bárðarbunga per second and come up in the hollow lava . Recent measurements indicate that magma under Bárðarbunga reach the two to three kilometers . ” However, the results show petrology studies of swarm loved unequivocally that it has not come up in less depth than 9 kilometers . ” This indicates that the dynamic system under Bárðarbunga is not just a simple chamber high in the Earth’s crust , but some . ” Or it is considerably high , several miles in height and dynamic to come from the bottom of it and the dynamic sit at the top , it is then not move it down just a victory . “

    • The change between 24/11 and 26/11 seems large compared to previous ones from this graph. Is subsidence accelerating?

      • The whole graphic seems strange. I can’t figure out a nearly linear subsidence in there that took place (we know thx to the Bardar-GPS).
        If the last two dates with -43m and -49m are right, a serious speeding up is happening.

        • Here is the giggle of the notes with the diagram

          We took a flight with TF-FMS yesterday, November 26. Sig Bárðarbunga was recommended and depth sigkatlanna in vesturjarðri and the SE corner of convexity.

          The following chart NS profile of the box set has been repeated on 5 September.
          Slowly reduce the speed sigs in the middle of the pack, but also has sunk extended. Change in volume sigkálarinnar from the last measurement (November 4). Measures 0:22 to 0:23 km3. This is equivalent to 130 m3 / s outlet magma. This is similar to the average for the period 17 September. – 26th November (140 m3 / s), but less than the first month (16 ág.-17. Sept.) When it was close to 200 m3 / s.

        • There it is written! Thanks Ian. 4. November.
          Time for a small reader comment on RUVs website. Not argueing, just for putting it right. Maybe they change it.

  13. gurgled …….This impressive lava waterfall has formed in the hollow lava . There is a new breach to the north reached lava front and flows like a waterfall out of lava .

    Lava now covers nearly 75 square kilometers . About 130 cubic meters of magma flow before Bárðarbunga per second and come up in the hollow lava

  14. Sorry to rabbit on about this but that eq – 06:14.02 6.9 km M5.1 4.8 km NE of Bárðarbunga
    fed right through to Hekla’s borehole strain gauge, there has to be a direct connection, maybe a conduit. It should surely have lost more impetus than this by the time it reached here –

      • I just think Its quite a feat delivering that level of shock through many miles of fractured rock and it arriving at the sensor still so strong, or am I just looking at it wrongly? The time of arrival appear more or less instantaneous.

        Hekla/Burfell gauges have been responding quite a bit to recent activity, and as has been pointed out by a few in here, in other circumstances that would be major news. It was only March past that Hekla was on alert level and in 2000 it was only 79 minutes after an eq that it erupted without warning.

        I dunno maybe I’m trying to make events fit a theory in my head.

        • None of the quakes on that screen relate to Hekla. They are Bardar quakes showing up on the Hekla instruments. I will definitely dance up and down when there is a Hekla quake, but there is not one on that screen.

      • Well, the interconnected idea has been put forth time and again. I even poked around in the quake data trying to find the much fabled Eyjafjallajökull-Katla connector to no avail. What I found pretty much confirmed that the feeder pipes trend away from each other with no hint of mingling. The astounding part about the Bardabunga eruption at Holuhraun, is that IMO tracked the dike from Bardabunga, INTO the Grimsvotn swarm, and then out to the Holuhraun site. That has never been seen before, and it even caught Carl off-guard. Now the GPS is seeming to indicate that Grimsvotn is showing a bit of deflation, likely meaning that some of it’s magma could be draining out through Holuraun also. That would be evidence of the Bardabunga magma actually affecting the Grimsvotn chambers. Again, something never seen before.

        All of this is amateur interpretation of the data presented. I am far from anything resembling a volcanologist. However, I do look forward to reading the papers that detail these possible never before seen interactions. They will be quite educating!

        • Think of it as an widening rift (the MAR) sucking in magma from the surrounding chambers. You don’t need to assume a direct connection between G. and B., just that both are leaking into the same hole. Possibly.

        • DING.

          I said that way back when. This whole pretty paper notion of ‘oh that was a *Grimsvotn* eruption from the *Grimsvotn* system in the *Grimsvotn* fissure swarm’ turns out to be a considerable oversimplification. We have to re-evaluate our concepts of exactly what a ‘central volcano’ IS, and a what a fissure swarm IS, in the context of Iceland. I’m not sure just how meaningful or helpful the concepts are. It’s certainly one of the ways Holuhraun is rewriting the books.

        • Yes, we need to rewrite books.

          Holuhraun proved that magma can travel in between 3 different volcanic systems, in a short period of time: Bardarbunga, Grimsvotn, and you forgot, Askja. Because Holuhraun is erupting inside the official Askja fissure swarm. And so, some of its earlier Holuhraun eruptions, thought to be from Askja, were probably from Bardarbunga, or even Grimsvotn. It gets confusing without a lava analysis.

          Another data pointing to Bardarbunga-Grimsvotn *indirect* connection is the events of 1996 at Gjálp.

          Also proven connections are between Grimsvotn and Thordarhyma, and possibly Bardarbunga and Hamarinn towards Veidivotn, and then towards Torfajokull (so, it could even be a connection between 3 central volcanoes separated by more then 100km)

          There is some data showing an indirect connection between Askja and Krafla, in terms of GPS. And let’s point that the first 1874-1875 fissure eruption, a dike from Askja, was nearly within Krafla system. Almost like the events now, but just involving two other volcanoes.

          A possibly similar case, and now I am just speculating, is between Hengill and Prestahnukur volcano. But here data is very scarse. I just look at the local geological and evidence of previous eruptions.

          Between Katla and Eyjafjallajokull, well we don’t see a connection between dikes, but that does not mean (just because there is an absense of earthquakes), that there isn’t a connection, the dikes might connect at a greater depth. In fact they have the same origin: Icelandic hotspot. However I favour more an *indirect* connection between both, as quakes in one, can trigger unstability in its neighbour, without requiring a proper *direct* magmatic connection

          There are other *indirect* connections. Shortly after Laki eruption ended, the strongest ever recorde sequence of SISZ earthquakes occurred in 1784. Five years down the road, another series of devastating earthquakes occurred in Hengill, with a non-magmatic rifting event occuring (a paper spoke of a magma-starved rift that never erupted that year of 1789)

          And recently, we have also speculated about an indirect or even direct connection between Bardarbunga and Tungnafellsjokull. At least there is an indirect causal link between them.

          But what drives most of this is two processes, and they go across volcanic boundaties: the tectonic and the hotspot plume.

          • This is very interesting. What would be a good reference for reading up on the proven connection between Grimsvotn and Thordarhyrna?

    • I’ve said on here many times that the Hekla instruments are very sensitive and pick up quakes from miles around – they pick up mega-quakes (over 7m) from anywhere in the world. The only reason to watch the Hekla meters (unless you are a Hekla nut) is as an early warning of Bardar quakes. This is actually better seen on the Brunnur screen now it is available. There is no direct connection between the two volcanic systems.

      • Maybe no direct connection, but according to IMO SW tip of Bardarbunga system is reasonably close to Hekla and Burfell which is why I keep it on my checklist, that and its reputation for unpredictability –

        • Well, obviously they are both on Iceland and both on the MAR. That green colour says ‘lava flows and thick tephra deposits’ from Bardarbunga which to me means above ground evidence of past eruption, not underground evidence of pipes and dykes etc..

          • Talla, Bardarbunga dike/ magma in years 873 and 1477 travelled all the way from central volcano of Bardarbunga until the place marked as Landmannalaugar and even a bit further southwest in year 873. It was a massive lava and also ash eruption (because riting fissure crossed a previous lake).

            So that makes twice Bardarbunga magma coming very close to Hekla volcano. I tell you how close: 15km.

            But if we extend the fissure swarm further down, it will not cross Hekla, but instead the highly dormant Tindfjallajokull central volcano (which by the way, had the largest explosive eruption in Iceland, in a long time, 54000 years ago)

            However the entire area between Landmannalaugar/Torfajokulland Hekla is full of small parallel rifting eruptions, so if we know one thing is that Bardarbunga dikes can jump into adjacent systems.

            I don’t say it’s possible such connection, but I also don’t say it’s impossible although pretty unlikely. However I came to think one interesting coincidence, that the birth of Hekla itself occurred at same time as the Thjorsáhraun eruption. And with it, I often had a crazy thought on my mind, whether it was possible that a dike from Bardarbunga could have gave birth to Hekla. I hope Carl is reading this… he is going to enjoy this thought.

            I mean we know nothing about what happened 8000 years ago, how Hekla was born. All evidence is covered by plenty of recent wide Hekla lavas. But under all of it, is the Thorjosáhraun lava which then emerges further southwest and runs all the way until the southwest coast of Iceland. In one of the most crazy events known to have taken place in Iceland. A 165km long lava river.

        • Yes, not exactly as you mean it, but there is a reason for this. Earthquakes wave propagation will lose intensity each time it travels through parallel fissure swarms (imagine waves travelling thtough alternating lines of ductile rock or magma, and then hard solid rock, and so on).

          There is only one system parallel to the Bardarbunga–Veidivotn-Torfajokull line, which is its neighbour Tungnafell-Hagongur-Skrokkalda and Hekla further southwest, if one could prolong that imaginary fissure swarm. So if the Bardarbunga quake is focused towards southwest it will have no trouble hitting very well the sensors at Hekla. And maybe that explains why before yesterday we even felt another quake of Bardarbunga here in the south of Iceland (which was a first time for us, in terms of Bardar quakes).

          I don’t think that magma is moving southwest. No. Otherwise we would see signs (earthquakes) at Hamarinn. But propagating waves and any new dike propagating from Bardarbunga could trigger a rifting episode southwestwards, which is our worst case scenario. We don’t want that.

          Just see the lava of the Thjorsáhraun eruption! I live near Selfoss, so a massive “tsunami” of lava 8000 years ago, was just running near where we live! It would be a total disaster. By the way, the worst case scenario for a Bardarbunga flood would travel more or less same path.

          • A lava tsunami coming down hill – an impressive sight from a safe distance. I would assume that even the fumes from such an eruption would already have led to evacuations.

      • Good morning/evening everyone. I’ve been regular visitor since someone published my video BBGlidnar203 here. I have found this to be an interesting blog.
        I made new video with small changes. The GFUM station is now on Hreppaflekanum and caldera is shaped like the one on the IMO images.

        I also made this system image some time ago if people are interested.

          • If you view the video you will see the opening of the fissure is at major in west and the east of the caldera . I think is obvious when you look at the cracks in the sand at the glacier snout, there would be water going down them if it is running near. It might also one of the reason that no water is coming from the glacier ?. Size is of scale in the image but it I believe must be at least some part of the system.

    • The earthquake signal is impressive.
      I was asleep and many were too, so no reports of having been felt.

      But it seems that this quake had an unusual propagation southwestwards. Not only Hekla instruments picked it very intense, but also Jon webicorders and the drumplots in south of Iceland.

      Per se, it means nothing, but I think its magnitude was probably near M5.5 and probably a deeper quake.

      When I woke up and saw this, I immediately thought, hmm, there was a really big quake somewhere in the world… but I was wrong, just another local Bardar quake..

      • I think the quake was inside the NE caldera fault. Reflections from the curved fault may have focussed the waves towards the SW?

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