Reykjanes surprise

Source: https://www.visir.is/g/20212093433d/ny-sprunga-ad-opnast-a-reykja-nes-skaga

The eruption in Geldingadalir seemed to be waning. The flows from the two cones were notably weaker this morning. The cracks in the back of the cones which has been emitting steam had stopped doing so. The raised lava pool in front of the cones was emptying, and earthquake activity was almost absent. Activity has gone up and down over the past week, but this was definitely a down. Even the Icelandic activist making a nuisance of themselves in front of the cameras (and not being a particularly good advertisement for the country) were largely absent. The valley was largely filled with lava but the edges were not rising very fast. Yes , the eruption was definitely in advanced middle age.

At 11:32 today UTC), weak earthquakes occurred in the area. They were only about 1 km deep. At 11:37 a stronger event happened. And suddenly, reports appeared of a new fissure which had opened. By luck, it was in view of the main camera (but behind the second one) and we had an immediate good view. The fissure is perhaps 500 meters long, is showing weak fountaining along its length, and is producing some lava. It is located 1 km northeast of the twin peaks. That puts it along the dike, and this is clearly fed by magma in the dike.

The location is on the high plateau adjacent to Geldingadalir. We have had discussions which way the lava would take out of that valley; the most likely route involved a roundabout way to get to the Meradalir valley. It was unlikely to make it at the current flow rate: it would likely solidify on the way. It turns out, the lava found a better way, underground. The new fissure is near a gully that empties into Meradalir. The lava quickly found its way into this gully (which is no more), and within hours reached the floor of the valley. It is now expanding into Meradalir, albeit out of sight of the cameras.

The map shows the approximate location of the new fissure. The accuracy is not guaranteed! (This is an updated version, which moved the fissure to the far side of the gully). (Update 2: the extended fissure is beyond the gully, as pointed out by Reykvolc. This has been added to the drawing.)

The map shows the Geldingadalir flow, as it was expected to develop. The yellow area shows what was needed to get an overflow into the next valley, with a roundabout path to the lower valley of Meradalir. The magma decided against this and choose a short-cut instead. The red line show the new fissure (it is a bit guess work and I have assumed it is perfectly aligned with the original fissure which may not be true). It shows the two gullies, and indicates the one which the lava has chosen.

What caused this new fissure? There are two possibilities. One is that the magma pathway to the twin peaks was beginning to be blocked, and that the backed-up underground flow found a new weak spot. The second possibility is that the dike was slowly closing as the magma inside was cooling and that this squeezed out the remaining liquid. To tell we need to know the composition of the new lava. It is hard to tell the viscosity when it is flowing through such a steep gully.

How will it evolve? If it behaves like a normal fissure, then the new eruption will quickly focus on one or two spots, with the rest of the fissure ending its activity. This may be happening already as most of the fountaining now comes from two or three spots at the middle of the fissure. However, there is also new fountaining activity at the end of the fissure where it approaches the gully. A southerly extension of the new fissure has opened up here in the past hours which may take over from the earlier fissure. Four cones can be recognized along the fissure, including two in the new extension. The northeastern end of the fissure has a ridge only.

https://www.facebook.com/Almannavarnir/photos/pcb.4244255905606160/4244254928939591

We already have the first time lapse of the new fissure, thanks to astropgrah99

It is guesswork whether this new fissure will become the main eruption site or that it will be a short-lived excursion. It is fun to guess though. If it continues, the fissure could extend further towards the valley, purely because that would be a shorter way to travel for the magma. It may be time for a new camera.

How about the old eruption? The activity there remains notably weak. The two cones are slowly being eaten away from the inside, with frequent minor collapses. The cones are both cracked and if the eruption continues, may collapse. The surface flows now stay close to the cones. They have build up a lava pond enclosed in levees, and every now and then a levee develops a leak and a break out happens. Much of the flow is out of sight. The flow rate is hard to judge by eye. The composition remains fairly primitive (for Reykjanes), suggesting this is magma that had collected around 15 km deep at the interface between the deep crust above and the mantle below. how long it spend in the dike is not known, but there was no indication that the magma was aging during the eruption. That would be expected if the eruption was fed purely from the dike.

Time lapses of the ‘old’ eruption thanks to Virtual

Finally, the poll we had on the duration of the eruption has given a clear winner. We had over 500 responses, from 40 different countries as far apart as Greenland and New Zealand. Regrettably, two voters had to be disqualified for submitting multiple identical responses. The electoral authorities in their respective countries have been informed. After this edit, we received the following votes (note that ‘Longer’ means longer than 5 years):

Interesting, if we look at votes from Iceland only (in the ranking of umber of voters per country, Iceland was fourth), a different picture emerges:

Are these votes from the Iceland tourist board? I guess time will tell! So far, this is a typical Icelandic fissure eruption with a dike, multiple eruption sites and some but not enormous amounts of magma. The only uncommon aspect is the lack of involvement of a central volcano. We do not expect that a central volcano will develop here: that is not the way of Reykjanes. Once this eruption is over (whenever that will be), the next eruption will occur somewhere else on the peninsula and it will firget about this fissure.

There have been suggestions a shield may develop here. That would be most unusual, but cannot be excluded. However the new fissure indicates that the eruption has not yet reached stability. Wait and see. Iceland may yet surprise us. Again.

Albert

687 thoughts on “Reykjanes surprise

  1. Perhaps the new fissure is extending to the northeast of the gulley?

  2. From https://www.facebook.com/Natturuva/posts/2875545335992888
    “Below are two different presentations of the same Q-lava+FlowGo model run, showing the most likely flow path of the lava from the new fissure. It predicts a main path through Meradalir, just as we are experiencing at the moment. Also, it is interesting that it is a possibility that these fissures, if they continue to erupt, may add lava to Geldingadalir.”

  3. Nice maps, but the fissures should be on the upper plane, north of the red arrow. From there the lava stream turns left onto the slide leading down to Marrakesh (no wait, it’s Meraldalir), towards the magic pond…

  4. That it nearly immediately opened up two new vents after the old one suddenly lost its mojo suggests that the magma supply below must still be healthy.

    I think that this vent was already there. Close to breaking through the surface.
    But just when it was ready to break through, Geldingadalir beat it to it and stole its fuel..
    So when this morning suddenly something disrupted the flow to Gelding. The new vent got the last push it needed to erupt. However seeing its still sharing its output with the Gelding vents. I doubt it will get the output as big as that one.

    Its interesting though that we will soon have twin volcanos, each consisting out of twin cones.

  5. Is there any possibility of obtaining the cracks in the ground map from the IMO? They seem to indicate that they were aware of the cracks before the fissure eruption occurred.

    • Thank you. Looking at the verified quakes map since March-29th is interesting (this map is not posted in the English version of IMO website) https://skjalftalisa.vedur.is/#/page/map seems to show the fissure extent underground from the Gendingdalir location clear to Keilar as delineated by the quake swarms. It is of interest to see the swarm near Keiler.

  6. Thank you Albert! I’m looking forward to new measurements of the gasses and the type of lava and what’s in it. The new fissure looks impressive.

  7. What are the elevation of the 2 sites ? Trying to find map on it. If someone have a good Map over aria i would be very happy. 🙂

  8. Remember how when the dike was first being created that it had a supply rate of about 20 m3/s, but effusion rate at the vent was never really close to that, the new fissure is bringing it up to about that now. Its hard to tell the effusion rate but it seems to be relatively much more than the first vent was, has got significant sustained fountaining at the start of the lava channel with a few cones growing already.

    • We don’t know the current effusion rate. You can’t easily tell by just looking. The fountains are not particularly tall and I don’t think the flow rate of the new fissure is that high. Tomorrow we may have a decent measurement. My guess is that the twin cones are down compared to the past. If the new is similar to what the old was than we are talking about 7-8 m3/s, but this is little more than a guess. I am happy to be proven wrong on this but I don’t see the evidence for a fourfold increase in eruption rate.

  9. There are two types of comments. Comments about metrics and theories about the eruption. And comments about amazing photos and videos. I usually post the first type but now for a change, I am posting this outstanding drone video.

    Wow what a river.

    https://www.mbl.is/frettir/innlent/2021/04/05/nytt_dronamyndskeid_af_sprungunni/

    When I lived in Iceland I remember driving through the south coast of Reykjanes and seeing steep cliffs with frozen lavafalls from quite high and I imagined it might have been quite a show when it happen thousands years ago. It turns out it’s happeninf again today.

  10. What a turn of events!

    Now we need a new webcam from the other side of Meraldalir, allowing us to see the lava fall into Meraldalir and the accumulating lava fan at its bottom. It would be quite a sight, particularly during the night.

    Let’s see how long it’ll take for the enterprising Icelanders to get around to it… (keeping fingers crossed).

  11. Albert, the new fissure is further west than you show. the short, lower section is clearly on that little triangle of land surrounded by valleys. Attached image made in paint shows location and the part of Meradalir valley covered a couple hours ago. The orientation comparing topography on map and in picture appears to be more north-south than for first fissure.
    https://imgur.com/a/jPz16tS

  12. Thanks again Albert! Couple of questions/thoughts though if I may?

    – No/little chance then that this is the result of an increased supply from depth then? (Perhaps the conduit began melting its surrounding rock deep down/upstream of the dyke feeding the old site, and this process found a new route to a separate dyke?)

    – Something I am struggling to get my head around: If there was a blockage of the conduit/dyke, causing a reduced flow from the old site and increased pressure leading to the new eruption, surely we would have seen a reduced flow but with higher pressure before the new fissure opened up (ie. less magma in the rivers/flows, but greater fountaining)? Instead, it seems like the pressure remained pretty constant at the old vents and did not change even with the opening of the new fissure (and surely we would have expected lots of new earthquakes during this process if it were driven by pressure changes).

    • The flow out of the twin cones is restricted by the width of the conduit below, perhaps 100-500 meters depth. If that gets smaller, less magma can be pushed through. As the output channel (the cone) stays the same width, the fountaining will not increase. You are thinking about closing off part of the end of a hose. But this is more like a constriction halfway in the hose. I don’t think there has been an increase in magma supply, because that would have been seen in the on-going eruption as well.

      • Couldn’t it be that due to the high temperatures the path to the new vent opened and that pressure release slowed the activity at the old cones down and not the other way around?

        • Who knows what happens underground! But I expect that a pressure increase would have aided the on-going eruption.

      • That makes sense, thank you – I appreciate the response! Presumably this is the working theory as it stands then:

        – we have a conduit “section” that has narrowed
        – the deeper magma supply upstream (ie. the piping closer to the MOHO) is likely unchanged
        – this magma found it easier to find a new route (potentially to an older dyke given the lack of earthquakes/tremor) – although the magma looked pretty primitive from the get-go so maybe it just exploited some major deformities from the tectonic quakes we’ve had in the region – to the surface as it was easier to do this than re-expand the pre-established conduit section

        If only we had the technology to know exactly what was going on underground, would love to know exactly what was behind these changes – then again, that might just take away part of the fun ha! Apologies for my ramblings…

  13. Just watched the mbl cam and the south cone had a collapse afain, although it quickly recovered. It seems it is getting back its strenght. Seems to me that these eruptions both will keep on going for a while.

  14. camera 2 has a nice view of some increased activity. Time stamp is 18:00 started around 5 min before.

  15. Wow, again spot on with all the information in one place. Can I add that the new valley is Meradalir, not Meraldalir? Think of a mare, and swap the vocals around. Mera = mare, a she-horse.

    • Thank you! Corrections are most welcome. Write in haste.. This has now been fixed

    • Within 3 minutes of the collapse of one of the new cones at the rift that started today. There was a surge of magma in the lower cone at the old site that allowed the lava to start flowing out.

    • One big change is that the right vent lose some altitude due to conduit crack….anyhow still working to that pizza oven …maybe got some production memory to fullfil?

  16. It is clear that there was a lapse in time between the time the lava pond lessened in height and the volume of lave emitted from the cones diminished and I am sure decreased in temperature before the new fissures opened up, I am guessing about 3 hours later. Clearly the loss of pressure at the original site was due to the new fissures opening up, not because the eruption was ending, which I mistakenly thought.

    My science questions:

    1. New flow rate? m^3/sec
    2. Old flow rate at 2 cones?
    3. Combined total?
    4. New cracks in the ground, does a topo exist showing their extent?
    5. Does quake swarms 4 or 5 days ago give a hint of new activity on the underground dyke
    6. Do updated SAR maps exist?
    7. Do GPS maps exist showing ground motion?

    What I find fascinating is the phase change in the lava at a certain temperature, when watching the pond overflow, the lava was very fluid, quite low viscosity, but below a certain temperature, all of a sudden the flow turned to Aa’ type, chunky, blocky and slow moving.

    My final question:

    8 What is the temperature of the lava emitted in the new fissures? It is very hot, based on how quickly it flowed into the Maradalir valley down the coulees.

  17. Did anybody hear squeaking from any of the cracks? If yes, that was most probably the former president.

    (Gggl translation of the visir.is page)

    • I almost chocked on my sandwich due to that Giggle-foo

      Today i was reminded that in Icelandic “tweets about…” and “squeaks through…” are the same phrase, you just gotta guess which 😂

  18. Kristín Jónsdóttir of the IMO office makes some comment https://www.ruv.is/frett/2021/03/18/bein-utsending-fra-gosstodvunum-nyjar-sprungur-opnast

    Google translates

    “It’s just that you should not let anything surprise you and this tells us that there is every reason for rescue teams and us to have this preparedness. The earth is reminiscent of itself, “says Kristín Jónsdóttir, group leader of nature conservation at the Icelandic Meteorological Office.

    She says that they have examined and mapped a large part of the cracks that are now erupting and are wondering why magma is coming out of them now and not when it started to erupt in Geldingadalur. “We do not fully understand what made it work.”

    She says the omens have been almost non-existent on the Meteorological Office’s measuring equipment this afternoon, some have talked about more gas pollution “but then it just happens.”

    She says that the new fissure is as long as the one that opened at the beginning of the eruption in Geldingadalur and that it is probably as big. It is, however, an impressive sight to see this lava river flowing down into Meladali. “You realize how hot and thin it is. It probably goes about ten meters per second, which is really fast. ”

    Kristín says that it is almost impossible to get to this area without being in danger and even though the lava flows in a narrow stream now it can change and there is a risk that people who are tempted to look at the eruption may become trapped. “This has become a more dangerous area than it used to be.”

  19. It’s snowing again. George RR Martin approves: it’s become “Game of Cones: A Song of Ice and Fire”.

    • yeap…I askk since yesterday were are the dragoons??? and yeap..The winter is comming! the new fissure got lenght and run toward the twins….

      • There were ravens circling the new fissure. Dragons can’t be far.

        • Jesus! you’re right I saw them both…so we have to expect 2 new events? or dragons?or the mother of the dragons is comming? cose the winter is already here…

  20. I wonder if as the exit of the lava gained height, it reached a point where it was no longer enough of a downhill slope to overcome the back pressure from opening the new fissures. I would guess the opening gained 20m+ since it started and was not gravity assisted as much as before.

  21. Do we have a new crack south of the new rifts showing around19:23:09 on camera 1?

    • Ahama but start to leak a lot earlier…and I believe that got to right a new head…tere is a small reddish point I also saw t previously

      • Or is simply the cam angle that’s tricky and in fact there is the lava river just leaking down and got some degasing points…

        • It is easier to see now. Perched river of lava overflowing at times. I think that the camera is also not level, making it look like it is running up hill.

  22. When the eruption started, there was earthquake activity in the northern and southern parts of the dyke and a silent area in the middle between Geldingadalir and a point just southeast of Þráinnsskjöldur. I speculated that the silent part of the dyke was silent because it is the transport path between the point where the dyke is fed from the mantle and the eruption site. The other two parts of the dyke show quake activity because the magma from the intrusion is just sitting there getting cold.

    Interestingly, the new fissure is along my speculated “warm” path. Maybe this is just part of a sequence where activity will gradually shift closer to the source and finally focus activity on a spot next to Þráinnsskjöldur, creating a new shield there.

      • Sorry, got the spelling wrong. Þráinsskjöldur, with one n.

        • Please belive me that n I dont iven saw it there…..you know..I’m an engineer and we are alike dogs, smart but also speechless. Its better to use graphics.

  23. As we dutchies have a saying this comes as ‘mustard after the meal’

    (Slow) timelapse April 5 04h00 – 12h45 Ruv camera.

    At the end the camera changes to a view of the new fissure being born.

    https://youtu.be/AyYnt4qCMEc

    A video of the other cam will be posted soon as well (but no new fissure, some great bursts though), but I won’t create a new post here. The blog is already overflowing with comments.

    I think I won’t do this as regular anymore. I simply don’t have the time.
    The volcano has more stamina than I have.

    Thank you for your kind words in comments about it

    • At 7:41 minutes into the timelapse you can suddenly see the smoke from the new fissure coming into the frame. That must be when the fissure broke. Shortly after the camera moves to the new eruption. The old eruption clearly suddenly diminishes a few hours earlier. I think that the new fissure is being fed by the same magma that feeds the old one. That would suggest that the new eruption is likely to cannibalize the old one. As Thomas suggests, the new one may be closer to the vertical conduit.

  24. Well, I don’t know; I get up, look at my iPad & the twin cones are fountaining away nicely & a break-out going on. I go to feed my chickens, come back in & the eruption seems to have dwindled down to almost nothing! I did wonder where it was all going… but was too busy to keep up until this evening. A surprise indeed! I look forward to the next installment…

  25. Well! What a turn of events! My first thought was “Thank goodness the Icelandic authorities and weather have kept tourists at bay. My second is , as every one else is thinking, what happened and what next?. Thank you Albert of keeping us informed….. So sorry if I bore you all with my “problem” But…….. My drainage is not going ahead until Wednesday , I shall be so happy when it’s all more sorted than Geldingadalur. This morning saw me scuttling to the loo next door in a horizontal snow blizzard. Thankfully the snow has melted but it’s still very cold. Visiting the bathroom in slippers and warmth will be soooooo wonderful!!! However at least Iceland is keeping my mind active and alert wondering why and what and away from my own vents, tubes,cracks and overflows.

  26. Last night about 8 pm I sent email to Dr Páll Einarsson about a new type of fissure ejection going on, where around 9:28 am local Iceland time, the bursts of lava became very sharp and decompressive, with the production of tephra, not the usual splattering that we see from the North cone. For one brief moment I saw the north cone eject a black cloud of tephra, which was rather startling.

    Dr Einarsson in his reply mentioned that “The transition to tephra production appears to have begun on Friday, April 2, see the facebook entry of Thor Thordarson, my colleague: https://www.facebook.com/thorvaldur.thordarson.7/posts/10221923826958794.”

    THis is very interesting in light of the fact that the two cones languished today, then a new fissure eruption started. Apparently the pressures in the dyke were such to cause this brief episode of teprahing on Friday and following then we see ground splitting and two new fissure eruptions starting today Monday (or one, if you want to link the two together by close location)

    • Ha, that was a good April Fools joke! It must have been Fool’s Gold which he found? Anyway, tephra is quite impossible in this type of eruption, that’s what we all have learned here on VC!!

  27. I am still waiting for a good metaphor that explaines why the eruption switched its focus from the valleys of the geldings to the valleys of the mares. Any horse breading geologists out there?

    • Someone to trot out a metaphor pregnant with meaning? Something able to sow the seeds of understanding and contribute to our galloping knowledge of volcanic processes?

  28. Visir has a nice clip from the upper part of the new flow. I think this is bigger than the other flows were, just look how the lava tumbles out of the upper cones of the new rift.

    And the narrower part of the stream looks like its building a roof for itself.

    The Icelandic daredevils better hurry up building that asbestos-boat for white water rafting down the new flows before it turns to a lava tube.

    https://www.visir.is/k/3879b742-2972-4254-b045-28d878fc34aa-1617640981775?jwsource=cl

  29. My tenuous supposition is this. At 7:44 this morning the back of the north cone collapsed – you can see it best on the mlb.is camera. There was so much it blocked the vent; perhaps it somehow blocked both of them. This increased the pressure leading to the new fissure. The tremor at faf changed at the same time.

    I should add, I know nothing about volcanos 😛

  30. Love the colours right now (21.00-ish). But I was wondering if someone sees the same thing I am seeing…

    The new eruption (btw it needs a better name) seems to be more of a rift with 2 groups of ‘cones’, 1 one the left and 1 on the right. Then you have the river flowing to the top-right of the screen before it drop out of sight. But on the bottom right I see some glow creeping towards the camera. Is there a chance this will flow into geldingadalir? Or towards the cam? Or am I just imagining stuff from watching the cams for waaaaay to long?!

    • Saw a drone flying around little while ago.. maybe its video can shed some light… hopefully someone finds it and post it here 🤞

    • You are right. It is a break-out that is slowly creeping towards the camera. If it continues it would eventually flow towards Geldingadalir. The main flow remains down the gully though.

    • See the diagram in Bjarki’s post at the top. It is from a tweet that is also found on the RUV page with the livestream – just scroll down.

      • Just to clarify, I was wondering if it was happening, because the screen on my phone is very small en zooming pixelated the image to much to be sure.

        I saw the graphs in the post, lightblue means it was unlikly to flow there (if I read those correctly, viewing them on phone also). So I was just checking I it was hopefull thinking on my part or actually already now flowing towards camera (and geldingadalir). Bit soon, but makes me happy nonetheless.
        Thanks Albert for confirming, happy I am not imagening stuff (or at least not this time 😉). And thanks eccentricviewer for explaining!

        Hope they put a camera on the other side though, love to see the “main” flow going down the gully like a waterfall.

        • kinvr25 ..

          Try the link in Diana Barnes post up thread @ 20:29 ..
          That’s the view you’re looking for ..

  31. We saw some lava simulations earlier here in the cafe. The models suggest that at one point the lava may also turn right (not left) after leaving the new vents, which would then not lead down to Meradalir, but – guess where? – back to the good old Geldingadalir.

    The new vents are close to something like a watershed, or in this case a lava divide. A slight change, maybe a small blockage, and the lava will turn the other way down to Geldingadalir. That right?

  32. It is amazing to see the difference between the old and tired looking cones in Geldingadalir and the young and vigorous new cones up on the hill. The way things go, the old cones may diminish step by step and soon stop erupting altogether. They were very entertaining during their prime.

    We’ll see how much of a spectacle the new cones can provide in their place. The long awaited lava falls are here already. As ulwur suggested, Icelandic lava rafting can’t be too far off now, can it?

    I imagine titanium boats with aerogel insulation, and passengers clad in silvery insulation suits. Just make sure the boat doesn’t capsize while going down the rapids…

  33. Not sure if this has beenput up yet (not sure how to post tweets so hope it works). Good map.

    Gisli Olafsson (@gislio) Tweeted: The location of the new fissure is shown on this map drawn a few days ago by @uni_iceland scientists under leadership of Asta Hjartardottir – they had seen cracks in the earth depicted in yellow and blue – and the Northernmost cracks are now forming the new fissure. https://t.co/lrqGbs6Cou

  34. With the current earthquake activity around Keilir, I wonder if we’ll get a vent in that area.

  35. Annnnnnd – here’s a new view from the ruv crews! @ 2231 yay 🙂

  36. New camera. On the mountain behind the old view of the new vents from camera 1

    • You can see both groups of vents and the lava pooling in the valley. See the vehicles just ahead of the lava in the valley. Old vents on left and new on right.

Comments are closed.