Bárðarbunga reader question

Image by Tom. Upper part shows a closed propagating dyke. The lower shows a rift open down to the mantle. The upper version draws its magma from a central volcano, the lower from the mantle. Upper alternative would give a smaller eruption than the lower.

Image by Margaret E. Hartley/Thor Thordarson. Upper part shows a closed propagating dyke. The lower shows a rift open down to the mantle. The upper version draws its magma from a central volcano, the lower from the mantle. Upper alternative would give a smaller eruption than the lower.

Richie, one of our readers emailed in a good question that is a good starting point for a brief update on Bárðarbunga.

Could you do an article comparing this intrusion to others? Looking at the post it appears that it is almost 40 Km long but how wide is it and in terms of volume. I am not sure if any diagrams are available to give an indication of the size underground. ”

It is hard to compare this intrusion to any other that we have instrumental data on. The main reason is that we have not seen one like this from a mantleplume volcano, nor have we seen something like this from a rift volcano.

It has a little bit of semblance from the Krafla Fires rifting episode. But I think that comparison is just too simple. First of all that was a much thinner intrusion that never reached this deep, so it was never even close to get down to the mantle. And the most obvious thing is that it kept to its own fissure swarm.

This intrusion has now been inside 3 different fissure swarms, and has the potential for more magma output when it breaks to the surface. In a way it is much closer to how the Skaftár Fires (Lakí) looked, but that eruption also seems to have stayed within its own fissure swarm.

Image by the Icelandic Met Office.

Image by the Icelandic Met Office.

I would now say that it is a unique intrusion and that makes it all the harder to understand and potentially more dangerous.

I am not aware of any exact diagrams or plots of the intrusion, but Tom made a couple that is interesting where he compares two possible solutions for the shape. One is a bottom closed intrusion with no mantle contact, and the second is a full Skaftár Fires version with a wedge shaped obloid intrusion open down to the mantle.

I currently think we have the first option, but that it is really close to the mantle and that it sooner or later will turn into option two. If I am right this will most likely lead to an increased risk for a flood basalt event.

The rift is now 45 km long and roughly 17.5 km high. Calculating the width is though a bit more interesting. If we take the east and west dilation between the Dyngjuháls (DYNC) and Kverkfjöll (Gengissig, GSIG) is by now 44.5cm. To get the correct values we have to take to recognize that the GPS-station are a bit far from the rift so the value is larger. Now, if we compare with the apparent dilation on further out stations we can roughly calculate that the true value is around 135cm. That would make the current volume of intruded magma into 1.05km3.

Update on Bárðarbunga

Image by the Icelandic Met Office. Note the curious pulsing of the magma reservoir visible in the up component.

Image by the Icelandic Met Office. Note the curious pulsing of the magma reservoir visible in the up component.

At the going rate the intrusion will slam into the eastern side of Askja’s magmatic system in 2 to 3 days. The effects of that could become slightly troublesome.

The large earthquakes are continuing at the caldera of Bárðarbunga and it seems like at least a partial ring faulting might take place there as magma rushes out from the magma reservoir. On the other hand the lowering of the caldera floor seems to be fairly small so the influx of magma is barely smaller than the amount going out into the opening rift.

Earlier tonight I noticed something interesting in the next volcano over. And that is that according to the Grimsvötn GPS it seems like the volcano is pulsing. That is a bit odd for a volcano that is not erupting and looks like it is not doing an intrusion of itself. And it becomes even more quirky since it seems to happen at the same time as the Bárðarbunga intrusion hits roadblocks.

One intriguing possibility is that the Bárðarbunga intrusion hit an old intrusion in Grimsvötns containing molten material and that it due to higher pressure in the Grimsvötn system took that infamous left-hand turn down Grimsvötns fissure swarm. It would certainly explain the marked pulsing on the GPS plot. Having Iceland’s two largest volcanoes force feed a rifting dyke could become slightly interesting in the future if it is correct.

CARL
Update:
Using Down Under ( Andrew)´s comments:August 27, 2014 at 05:04

Everybody, please welcome the dike into the Askja domain.

Credit IMO 27.8.2014

Credit IMO 27.8.2014

bvservlet-1

He also did some trajectories starting August 28th

Down Under (Andrew) August 27, 2014 at 05:04

and August 29th:Down Under (Andrew) August 27, 2014 at 05:08

www.midhus.is webcam pointing at Bardarbunga Up in the sidebar of VC

http://www.midhus.is webcam pointing at Bardarbunga
Up in the sidebar of VC

Spica

1,502 thoughts on “Bárðarbunga reader question

  1. Go team Grimsvotn! 😀

    Tuesday
    26.08.2014 23:23:49 64.410 -17.410 0.1 km 2.0 99.0 6.6 km W of Grímsfjall

      • Is it coincidental that the larger quakes seem (I cant find a program to plot far enough back) to be happening around low tide in the region, ie relieved pressure on the plate tectonics?

  2. Gus – Nope they stick with low values at 99% for hours sometimes then jump to 5.x – that’s been the pattern.

    EMSC detected a 5+ from many sensor networks.

  3. The “most likely” scenarios from IMO and IES scientists seem a tad less dramatic than a lot of the predictions I have read here and in other places.

    26th August 2014 11:50 – from the Advisory Board of scientists
    Scientists from the Icelandic Met Office and the Institute of Earth Sciences, and representatives of the Civil Protection in Iceland, attend the meetings of the Advisory Board.

    The following three scenarios are still considered most likely:
    -The migration of magma could stop, accompanied by a gradual reduction in seismic activity.

    -The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dyke. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.

    -An alternate scenario would be the dyke reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
    -Other scenarios cannot be excluded. For example, an eruption inside the Bárðarbunga caldera is possible but presently considered to be less likely.

    • I hate to disagree with IMO, but they are working on a model based on the Krafla Fires (their own statement), and that is by now a false assumption that senior volcanologists have started to doubt. Chief amongst them the godfather of Icelandic volcanology.

      Do note that the difference in what I believe and the current IMO statement is actually minor differences in percentages (not that any are given). My last two articles have mainly just pondered on one of the less likely scenarios since I find it scientifically interesting.

    • “-Other scenarios cannot be excluded. For example, an eruption inside the Bárðarbunga caldera is possible but presently considered to be less likely.”

      I think this is the key. Like Carl was saying a lot of the people here more or less agree with the IMO’s statements of the “most likely” scenarios to one degree or another. Here, we get to talk about the “other scenarios.” IMO, due to being the official source for information, isn’t really at liberty to speculate (through official channels at least, who knows what is being talked about behind the scenes) on other scenarios until they become increasingly likely due to the possible alarming nature of those scenarios. Can you imagine if one of the bullet points was the following:

      “- A rifting fissure eruption forms and develops into a Skaftar Fires (Laki) type event as magma erupts from the mantle through the rift.”

      Even if they gave the caveat that the likelihood of such a scenario was say 10%, the media would have a field day. “Dire predictions from Icelandic officials” “Could Iceland split in two in a fiery eruption with global consequences?” Then after a media fueled hype storm and 24/7 RiftWatch, one of the “more likely” scenarios occurs and a small surface fissure takes an effusive lava poop on the glacial floodplain and now IMO ends up looking like a bunch of fear mongering incompetents despite their best attempts to manage expectations.

      One of the reasons I like this site is that most of the posters are driven to provide data-driven predictions and fact-based discussions where alarmism is looked down upon. It doesn’t mean that people can’t ask, “What if?” and get some realistic answers though.

      • I can say that there is a tendency both in the media and sources that potentially feed it to be very politically correct and to discount, minimize and downplay possibilities of anything that could be perceived as destabilizing, having the potential for economic hardships or that could result in a level of fear that would impact consumer confidence, travel and commerce, etc, etc. This is because there has been so much change and destabilization on so many levels. People are shell shocked and are trying to forget all the things that are going wrong. They want to forget about the recession, about all the wars, the global weather extremes, volcano’s, all the preppers, etc, etc. ad nauseum. Its very politically incorrect and almost offensive for anyone to say something “alarmist” or fear mongering. When soldiers and shell shocked and coming back from a mission, they don’t want to hear gory details about the dangers of the next mission. They want QUIET! But Volcano’s and tectonic plates are going to ignore those people and do whatever they do. And we are in a period of increased volcanic activity in Iceland and things are heating up and we don’t know where this is heading. Humans hate: danger when it is unpredictable and they don’t have control over it, where they feel helpless. So, they want to hear things like, “we have downgraded the flight alert to orange and there is currently no volcanic activity and its very unlikely we will see an event like April 2010, etc, etc. Make everything go back to normal like it was in a couple of words to make us feel good. Volcano’s don’t care. Find another way to “feel good”

    • There are a few reasons.

      1. IMO has to operate strictly off known science and hard facts, especially in their reports and publications. The problem here is that there really isn’t much for them to compare this event to. Krafla fires as Carl mentioned is their best bet, but this is a lot different than that event already.

      2. This is a volcano blog. We try to keep this very scientific, but compared to volcanologists and the scientists writing papers for peer review, we get a lot more room for speculation, so we can operate with a little bit more opinion and theorycraft than they do (at least in our commenting).

      3. Much of the data and information about the Skaftar fires that people are referencing here was done independently and by Carl himself (I believe). As such, information we’re using here to model a potential eruption is not information that IMO can use when trying to make scientific predictions and risk mitigations. Despite how big of an event it was, there just isn’t a metric ton of research done on the Skaftar fires, and it’s likely that quite a few pieces of the information there is outdated anyway.

      4. Even in the event of a big eruption, Bardarbunga is quite literally in the middle of nowhere. IMO has much more to lose by scaring the population than they do by notifying the populace of the risks (even if they’re hypothetically understated).

      5. Since this is a volcano blog, we like discussing potential black swans and bigger events. Theorizing about the possibility, the why, the science behind such events is much more interesting than discussing a small and benign eruption such as what we see at Hawaii all the time.

      • Exactly my thoughts. I agree especially with #4. There is more potential downside to creating fear than being able to say, “I told you so” or we were wrong, but we did say anything can happen. This is what makes this and Jon’s blog so great is that there is a free exchange of information where there are no stupid questions or idea’s and no harm in conjecture. I feel comfortable being stupid here, which I am 🙂

        And like Lee stated, we do have the luxury of exploring all relevant possibilities based on piecing together data, history, geomorphology, etc, without the fear of creating fear or harming our PhD reputation. So then, I will say it: This current activity, in my opinion, in this glacier, has the unquantifiable possibility in the coming years of affecting crops, weather, economies, lives, etc, and the risks are mounting. Not alarmist, just an increasing risk that can’t be quantified and that time will bear out. Having said that, hopefully, Barda’s magma will blow out some fissures away from the glacier and be short lived and calm down for another 100 years.

  4. Anyone getting anything out of the Askja drum? 17:20 last reading! Is it common for the drums to go down? What does it entail to repair-a helo and a hike? Thanks That caldera rim is just getting hammered- the ring of fire is near complete!

    • “Repair a helo?” Well, a couple of my acquaintances used to work in aircraft maintenance in the depot level repair facility here in Pensacola back before they BRACed it out of existance. If you wish I can actually go ask them. One, however, is going through his second childhood and is sporting around town with his new girlfriend. Evidently his stint worked quite well.

      • I think he was asking what it takes to repair a downed seismometer at Askja… A helicopter ride, and a hike on foot?

        Btw, I’m also in FL… Tampa.

  5. If high pressure at Grimsvötn pushed the intrusion away towards Askja, wouldn’t Askja conceivably do the same once the intrusion makes direct contact with Askjas magma reservoir? I am assuming it is very pressurized given the time since the last eruption in the 60’ies. The question may then become where it then goes… Hardubreid?

    • Askja is not having that much pressure, it deflated from the start of Krafla Fires untill recently. It is not even back at the levels prior to Krafla. But I am more thinking about old pockets of Rhyolite.

      • Good point, although I find it strange that Grimsvötn has built up such a strong pressure compared to Askja given its recent massive eruption and the fact that it has seen few earthquakes (and presumably little filling) since then

        • A lot of filling again at Grímsvötn and very fast, also:

          (Univ. of Iceland data)

          Has anyone GPS data from Askja?

  6. @ newbies…if it seems like old friends are gathering for a party, (hello P.Frito!) this blog started around the time of the Eyjafjallajokull eruption….many of us lurk, drop in from time to time as life permits, etc…but, when it might be party time…..we gather by the fireside knowing that any and all have a chance to contribute to the conversation…however, over the years Carl, the dragons and studious posters have done such a fantastic job of education that many of us lesser mortals are by nature more than content to just provide the virtual coffee cups and Bardycakes, which are being stockpiled now….

  7. Magnitude M 4.2
    Region ICELAND
    Date time 2014-08-27 01:52:04.0 UTC
    Location 65.08 N ; 16.97 W
    Depth 10 km
    Distances 258 km NE of Reykjavík, Iceland / pop: 113,906 / local time: 01:52:04.0 2014-08-27
    85 km SE of Akureyri / pop: 16,563 / local time: 01:52:00.0 2014-08-27

  8. As a usually silent reader on the blog I want to express a big thank-you to Carl and the other contributors. I’m curently on holidays (at Yellowstone at the moment! :-)) and I’m following the events from the hotels with WiFi.

    What I really like is the presentation of many possible scenarios and the possibility to make up your own mind – especially long-term-followers learned a lot of things about the geology of Iceland. Being a scientist myself I really like the approach of this blog.

    And even more – once again Iceland gave a clear demonstration that it is always open for surprises. Two weeks ago I still would have put Hekla or Grimsvötn on the top of the list for the next eruption – and it still can happen. 😉

  9. Very sharp uptick in tremor just now. I have a feeling our “stalled” swarm is about to jump forward. I guess time will tell if I’m right or not.

  10. Magnitude M 4.2
    Region ICELAND
    Date time 2014-08-27 01:52:04.0 UTC
    Location 65.08 N ; 16.97 W
    Depth 10 km
    Distances 258 km NE of Reykjavík, Iceland / pop: 113,906 / local time: 01:52:04.0 2014-08-27
    85 km SE of Akureyri / pop: 16,563 / local time: 01:52:00.0 2014-08-27

  11. Thank you, everyone, for elevating my volcanic knowledge by several orders of magnitude!

    In these eruption scenarios, we talk a lot about explosive forces, ash deposits, and quantities of lava. With a girlfriend currently in The Hague, has there been any modelling done on LEL-concentration of SO2 plumes during eruptions? Does the concentration or relative quantity of sulfur dioxide emitted per km3 of lava erupted vary globally, or change based on the type of event?

    -A Friend in Texas

    • None that I have seen. However, from past SO2 and Sulphate modeling off of a paper that I read, whatever the amount of SO2 that gets lofted to the stratosphere, it will peak sulphate levels there about 2 to 3 months later, and that will last anywhere from 40 to 80 months until it sediments out.

      I used a one metric ton release so that the graphic could be easily scaled to whatever amount actually gets lofted.

  12. As someone who has wandered here randomly, mainly since I am planning to visit Iceland in 2 weeks time… can anyone (or Carl) give me an idea of how the scenarios could threaten the area around?
    As I gather, Bardarbunga is in the middle of nowhere and in the case of an eruption, the ash is more likely to be wet and heavier than the dry ash of Eyjafjallokull. I know this article was a little more speculative but what radius of area could be threatened and how would areas on the periphery f Iceland be threatened (if at all)?

    • We won’t know until it starts. Please read Carls post ( 2 days ago) were he speculates on possible scenarios. But until B blows, there is no way of knowing, if it starts that is.
      We will try to keep you updated on this blog.

      • Thanks all!
        I have been following a lot of the possible scenarios, both here as well as the IMO’s and yeah, it doesn’t seem as terrible unless you actually camp out in the Vatnajokull… 🙂 Convincing my gf is a trickier proposition.
        That said, my main source of curiosity lies in how the extension of the Dike could possibly affect the current events. IMO mentioned the Dike extending upto the Askja volcano perhaps and the rift is over 40km long now. Can this lengthening of the rift and “meging” with other volcanoes in the area create a bigger event perhaps, especially if it just keeps festering for a while?
        I believe some tremors were felt in Akureyri town which is quite far away from Vatnajokull!

        I hope some of these questions make even a little bit sense. 🙂

  13. And another green star at Askja… this one initially labeled 5.2 by IMO

    Edit – Apparently another 5+ at Bardy?

  14. Interesting thing about the most recent 5.2 quake at Bardarbunga is that its at 12.9 km depth. Almost all the other quakes at Bardarbunga (especially the large ones) have been between 2-6 km in depth, the area where the magma chamber would be..

      • Pure Speculation: Mantle Magma conduit collapsing under frictional flow/pressure?? I noticed that!–Interested to read those much more informed! Trying to construct a visual dynamic model- and event or trend removes the logic and keeps me guessing:)

        • Maybe… but the distance is given as 9.6km which is likely to be measured from Bárðarbunga’s centre point. Given that the main crater is 11km across, this would put the quake at least 4.1km outside the main crater so it may have more to do with the pressure/strain (not sure which is the right word here) on the rock walls down below as more magma is injected into the system. I notice from the tremor chart that the red spiked just as or before the ‘quake started and as the red line (low hz) indicates magma flow, this could be what is happening.

  15. The Baering site is showing two simultaneous 5.2s, one in Bardar and one at Askja. Is that a glitch or did that really happen?

    • It was initially reported at the edge of the fissure and was corrected to near Bard. They’re not handling the correction properly.

      • I noticed some days ago that the Baering data wasn’t well correlated to IMO data. I’m not sure why that is.

  16. On another note, who was the person making up the dispersion maps, might be time to make a new one including the projected path of Hurricane Cristobal on rsoedis alerts, heading straight for Iceland in a week or so, given it will be in a diminished state, it’s circulation patterns will still exist.

      • I think you’ll find that these earthquakes aren’t actually at Trölladyngja but 19-21km east of there, ie in the intrusion line.

      • Herdubreid

        It has been rocking for years now but as close to 100% of them as makes no difference have been tectonic. That said, there’s a great many deep and wide cracks that are just waiting to be filled with magma. Alas, it is on the Eurasian side of the MAR with Askja and the intrusion on the other, American side, so an eruption there is highly unlikely.

        But let’s speculate! Assume that this intrusion somehow avoids Askja, doesn’t break through elsewhere and reaches Herdubreid where it eventually breaks the surface at the top:

        * Big quakes as the intrusion makes its way through Herdubreids by now almost certainly solidified conduits. Massive rockslides on the flanks
        * Initial eruption BOOM. Explosive VEI 1-2 as there cannot be enough old, fractionated and eruptibleandesitic-to-dacitic magma
        * Hawaiian to strombolian eruption that goes on for weeks to months that could erupt in total anything between 1/4 to several cubic kilometres of basaltic magma
        * The magma reservoirs under Bardarbunga would probably empty to the point where they cause another, smaller, caldera collapse like the one five hundred years ago or Katmai in 1912
        * Herdubreid would turn into a shield volcano with an odd hump in the middle where the old tuya will be buried – new word: sublavatic.

        If this very unlikely event came to pass, it would be the most photogenic eruption of this and the past centuries my friends. Even if we’d lose the most beautiful tuya on the planet, the exchange would be well worth it.

        Mind you: SPECULATION ONLY!

    • I’m excited to see what happens. There was a 5.3M at the west side of askja around an hour ago. Though the caldera is prone to landslides but I haven’t seen one that large near there. And there were two very large ones at Bardar again

  17. The dike punched through and is again starting to move north! That is also the reason for the tremor uptick.

  18. Question — are there any sources of drum recorder data that detects lower frequencies (~1 Hz) that are associated with magma movements? My understanding is that the existing drum recorders available on the web are sensitive to higher frequencies, like 10 to 40 Hz, meaning we can’t really get a handle on harmonic tremor activity. Alternatively, is it possible to use the raw data to filter for the long period frequencies? I’m not sure why we’re not using this data.

  19. Does anyone have an explanation of why the Bardarbunga-caldera EQ’s seem to be getting progressively deeper over the past 36-48 hours? The Baering plot does a good job of showing it.

  20. I cannot take credit for the Graphic used Carl. That is taken from page 2 of this paper: https://www.repository.cam.ac.uk/bitstream/handle/1810/245154/Hartley%20and%20Thordarson%202013a%20-%201875%20volcanotectonic%20episode%20at%20Askja%20lateral%20flow.pdf?sequence=1

    Excellent paper that Mopshell came up with from Margaret E. Hartley/Thor Thordarson by the way, explaines what was going on around Askia at the Nýjahraun eruption and may help understand (at least for me) what is going on now. It states for example that Lava previously erupted where the current dyke is, was likely from Bárðarbunga:

    “The Holuhraun basalt is more similar to lavas erupted on the Barðarbunga-Veiðivötn volcanic system than to postglacial basalts from Askja, indicating that particular geochemical signatures are not necessarily confined to the tectonic or structural surface expression of single volcanic systems. ”

    The paper goes on explaining the Holuhraun area:

    “The older ‘‘Holuhraun-1’’ lava was erupted from a 2 km-long fissure located 15 km south of Askja,while the younger ‘‘Holuhraun-2’’ lava erupted from a fissure that begins 23 km south of Askja and extends southward beneath Dyngjujökull glacier. Historical accounts can be used to tentatively date these lavas. It is known that new lava was erupted north of Dyngjujökull between 1794 and 1835, where previously only a sandy sediment cover had existed [Jonsson, 1945]. The eruption that produced this lava, Holuhraun-1, most probably over the winter of 1797. Holuhraun-2 is possibly associated with fiery eruptions seen in the Dyngjujökull region between 1862 and 1864. If this is the case, then the Holuhraun-2 fissure was active at the same time as the Tröllagıgar fissure on the Veiðivötn volcanic system. “

    • And some projections for the heck of it:

      I have put the relative humidity (moisture) on the bottom table, so we can get the idea of the moisture the ash could go through. And repeating, that these flow projections are not actual ash dispersion. These just show the road that ash can take, but not how far it would get, since that depends on the ash characteristics.

    • Hello Andrew!
      Remember that these are unverified quakes. When I check with verified quakes image the intrusion is not at Askja yet. About two to three days remain before that happens.

      • I’m going to plot the verified quakes from Dreki and see what that looks like. Now that the intrusion has moved off the glacier (not literally of course as it is/was underneath the glacier but you know what I mean 🙂 ), location measurements on IMO’s table appear now to be taken from either Trölladyngja or Dreki rather than Kistufell. There are still mentions of Kistufell but fewer and fewer as the intrusion moves north.

          • I’m just interested to see if using Dreki and Trölladyngja as reference points is a good way of illustrating the distance of the dyke intrusion from Askja. (graph on following page). Oh and it’s fun to do! 😀

  21. For the plotters and code fiddlers out there.

    Based on the recent large quakes, my formula for estimating Mo from the magnitude is now

    =10^(9.13+1.489*Mag)

    Results are in Newton-meters. The formula has a 0.9991 correlation factor in matching ESMC derived tensor solutions. Previous versions were 0.9989 and 0.9990%.

    • EMSC → European-Mediterranean Seismological Centre

      Mo → Moment magnitude. The actual energy release from a quake.

      Just be glad I am not using my Twinkie™ analogy… I used to express quake sizes in Cheeseburgers and Twinkies, just to point out how small a particular quake was. This was a take-off on the Ghostbusters Twinkie reference… which actually had a lot of errors… mainly in the mass of the twinkie they mentioned. It would not have weighed 600 lbs based on their dimensions.

    • Ok so I have a question – I’m liking the plots

      lets assume the ash cloud reaches 10km altitude in an initial plume
      obviously to reach that height – it needs to pass through all the heights below that
      and lets assume the eruption lasts 1 week – and keeps kicking out ash to the 10km height (I’m not sure if that is actually plausible – lets assume it is for a minute)

      so looking up at this chart http://shrani.si/f/3O/H6/3BSfh5Zm/142403trj001.gif

      I wonder what percentage of ash would follow the 10k line – does the ash spread out between the red blue and green lines in proportion to where the bulk of the ash reaches in the plume height ?

    • Oh, also I see the winds in the http://shrani.si/f/3j/Zt/1xZrmWLu/142618trj001.gif plot cross where I think the ural mountains are – is that what makes the lines which were heading toward lower altitudes head back upward ?

      how tall are those mountains in that region – do they normally get a lot of rain (I think air rising normally causes rain – right?) would that wash most of the ash out ?

  22. I have recreated the Energy released per location charts. In order not to spam this thread I’ve put them on Pbase in a folder http://www.pbase.com/its_tom/bardarbunga

    Would you rather have it this way or directly linked into these threads?

    Energy still in GJ. some graphics topped to 500GJ or even 5GJ to show the dyke.

    Question: While the surface graphics look nice I think they distort way too much when I cap the max value. Shall I do bar graphs only?

    DragonEdit: All commenter created plots are prefered to be as images. /Carl

    • Ok, will link them directly then in future. Data from 16th until 24th by DFM.

      Still open question: While the surface graphics look nice I think they distort way too much when I cap the max value. Shall I do bar graphs only?

  23. Interesting charts Tom… is it possible to plot them somehow as a function of depth, like latitude for X and depth for Y? It would be interesting to see how the energy distributions work out vertically.

      • That’s it! Interesting, I figured there’d be a rather uniform distribution from 0 to 10 km but it does look like it peaks at 6 km depth.

        • Remember that the 5.7 probably had more energy than all others combined. I’m sure someone can calculate that for you 🙂

            • When you create a chart in Excel, it will set up the X axis in ascending order. To change it:

              > click on the X axis and it will show in a ‘box’;
              > right-click inside the ‘box’
              > choose “format axis” in the pop-up;
              > the “axis options” pop-up appears
              > check the “Values in reverse order box”
              > close the pop-up and you’re done!

  24. Loco mentioned in the last comment page on the previous post, that Hurricane Cristobal is heading straight for Iceland in a week or so, and though she’ll be in a diminished state by the time she gets there, how will she likely impact on the weather and trajectories? Perhaps though it is too soon to say as hurricanes, though more predictable than volcanoes (most things are!) still have an unpredictability of their own. I know this from living in a cyclone area myself. 🙂

  25. Traveling today – very exciting – you all are our main ancker in not letting ourselves being confused by fears of family and friends ;-)) See you on the flipside – and thanks so much again and again

    • Only in the blue 2 – 4 Hz range (water). The line that matters, the red 0.5-1.0 Hz line where volcanic tremor appears, is still well within range. Nvm the blue line!

  26. @Mopshell

    Well I’m just waking up here so I’m slow to take things in – needed this second look so thank you for that. 🙂 By the way, the dragons are going to spank you for posting an en.vedur.is link! No, absolutely none, nada, nil en.vedur.is links allowed! Info yes but NOT the link. And trust me, it’s best not to annoy dragons!

    Thanks Mopshell!

    I try avoid not to annoy dragons!

    DragonEdit: Here is your cake ilel100

  27. If my questions been looked at but ignored, that’s fine, if it’s overlooked then here I mention it again.
    Is it purely (as far as I can get charts to work for me here and data I have available) coincidence that the biggest quakes seem to be happening relatively half an hour either side of low tide for the region?

      • The Moons influence of the lava level must be microscopic compared to the massive headlosses pushing thru the dyke?

        • I was just curious, as someone pointed out (might have been Carl) that they felt this event was tectonically driven, thus with low tide there is less water pressure in the plate region.
          The biggest ones seem to be low and night time, rather than low and day, though there is a peak around the day low, just not as severe.
          Or it’s just coincidental data. I haven’t got access to records beyond the last 36hr, to make a better pattern.

          • It’s not far from the coast but but does the tide really influence the ground water level 50km from the coast?

            • Not a question I could answer.
              The gist of my question wasn’t about ground water but rather changes in sea water mass on plates, I mean if you carry a full bucket of water (influenced by gravity) and dump more than half out, it get’s easier to carry, thus if you are exerting the same amount of muscle force to hold the bucket it would rise upwards gradually as you emptied it. So in that perception as tide goes out for the region, there is less water mass (oceanic) on the two plates, relieving pressure that then could be inducing the major ones in this situation (only).

              Someone already made a pattern that the tremor lows and highs were pretty much lining up, but that doesn’t indicate what is causing the bigger quakes, just that the bigger quakes are followed by rises in tremor. My question wasn’t linking to that.

            • Loco, there could be a connection, we have Sea tides and also following by Earth tide. Big forces pulling the Earth in different directions by the Sun and Moons gravity.

    • As for your question, I understand from previous comments that if there is a pattern in the data (as can be seen on the tremor graphs) that pattern is probably a result of meltwater, as a lot more ice melts during (sunny) daytime. So you may be right in seeing a pattern, but it is not the tide. (I’m not an expert at all, but from what I’ve read, I think all the experts on here agree that the tide/moon is not a factor in this. )

    • Now for a serious answer.
      No, there is no effect whatsoever. Volcanoes are only affected by tidal waters if they are islands in the process of being born.

      • Thank you.

        I won’t grow in knowledge if I don’t ask the questions. Just thought I saw an inkling of pattern.

        My line of thinking had nothing to do with the doomsdayers and nibirutards etc.

    • Let’s have a look at that:

      27.08.2014 _ _ _ 2:50am _ _ _ 5.2 _ _ _ 7.5 km E of Bárðarbunga _ _ _ Low tide: 12:46pm

      27.08.2014 _ _ _ 12:16am _ _ _ 5.4 _ _ _ 3.2 km SE of Bárðarbunga _ _ _ Low tide: 12:17am

      26.08.2014 _ _ _ 1:26am _ _ _ 5.7 _ _ _ 4.8 km NNE of Bárðarbunga _ _ _ Low tide: 12:26pm

      25.08.2014 _ _ _ 4:19pm _ _ _ 5.1 _ _ _ 4.1 km SE of Bárðarbunga _ _ _ Low tide: 12:06pm; 11:49pm

      24.08.2014 _ _ _ 8:39pm _ _ _ 5.3 _ _ _ 8.1 km E of Bárðarbunga _ _ _ _ Low tide: 11:20pm

      24.08.2014 _ _ _ 5:33am _ _ _ 5.1 _ _ _ 4.6 km SE of Bárðarbunga _ _ _ Low tide: 11:47am

      24.08.2014 _ _ _ 12:09am _ _ _ 5.3 _ _ _ 1.9 km NNE of Bárðarbunga _ _ _ Low tide: 11:47am

      The second in the list is the only M5+ earthquake at the same time as low tide and that’s a coincidence as none of the others have any correlation whatsoever. 🙂

      (Tidal times: http://magicseaweed.com/Iceland-Surf-Report/2855/Tide/?start=1408856400&end=1409720400 )

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