Reykjanes surprise

/ 05/04/2021

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

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687 thoughts on “Reykjanes surprise”

  2. Lava effusion rate update 7m cubed/s new fissure 3m cubed/s old one for a total of 10m cubed/s

    [Welcome! First comments are held for approval, but here you are! / Lugh]

    • okay, the first 3 of my science questions answered. Hoping to see land uplift and crustal motion from SAR and GPS

    • The trigger for the new fissure opening seems to have been an increase in the supply rate of Magma from the deep fissure (or dyke). At 07:22 or thereabouts, lava was emerging at the two vents in Geldingasdalir at a very high rate and breaking out of the levees of a very full lava channel, including one spectacular breakout in from of a rather surprised spectator.

      Then, suddenly the flow rate decreased from both vents, and all the lava channels on top of the main flow drained down by a few metres. This drop in flow rate (in hindsight) is probably the moment that the new branch of the fissure opened and magma began to head northeastwards. Several hours later, this magma emerged at the new fissure(s)

  3. They switched the new camera on at time stamp 22:29:50. At the time of the switch you see lots of vehicles headed down the hill.

  4. https://www.youtube.com/watch?v=OEYCQvKtR8w
    Bjorn Steinbekk – A guy with a drone
    He is good, he has destroyed 3 drones already as with the other videos, breathtakingly close to lava. This video is a taster I presume, the new fissure at an earlier stage before the lava river got right down into the valley.

    • Great video! Looks like he may have roasted another drone just for this video, almost going through the eruption towards the end. I felt the sizzle just by watching…

    • Holy cow! That’s crazy sending in a drone so close to the lava, especially the fountains!!! Great find, though!

      It must get pretty expensive to go through so many drones.

    • Now its got message retracted, so it must be taken as no action near Mt. Keilir after all.
      That would have kept me awake alright!

    • If you scroll back to 2200 and then backwards from there, you’ll find fountains for pretty much all the vent openings.

      It’ll help with trying to keep perspective with regards to the new view….I hope the first camera is kept active as well! (gotta cost a lot, though!)

  7. Looks like another breakout at 23:26 pm, next to the two cones, but on the line to the new fissures.. showing up in the camera now as a new light

    • Must be a pond breakout, the camera is very sensitive to low level light, and the creek of fast flowing lava from the new fissures is ponding up on its way down to Meradalir, then when the ponds get full, there is a breakdown down the small canyon to the next pond.

  8. I see the regular camera has moved to Maresdale lava river. Is there one available for the fires?

  10. I don’t know what that is, RUV, but it is not 720p. 😛 (00:17)

  13. Amazing shot of the heat sources moving the fog/mist almost vertically. 🙂

  14. Well 90 minutes of observing from the new RUV camera has shown that the fissure lava flow is definitely occurring in surges, separated by at least an hour or so. A fresh surge is on the way now 00:45 am 6-April-2021 as made obvious by the bright glow in the sky.

  15. If you are interested in the potential of this event, just look at the surrounding terrain.

  16. Pacaya doing its best to get some attention, massive lava flows etc. but too bad, everybody watching the Icelandic puppy.

    Mauna Loa and La Souffriere both having some grumbles too.

    Since we have become single laser focused on Reykjanes who is doing the general around the world news?
    https://lechaudrondevulcain.com/blog-spotlight-two-column/ seemed to have pretty nice world view.

    • Yes, I can recommend him. Pacaya’s lava is endangering populated areas

    • And a basalt thats faaar cooler and more viscosity than Fagradalsfjall .. Pacaya makes huge Aa rivers .. smooth channels almost does not exist

      Pacaya is alot cooler and that does the diffrence in viscosity.

      Still pacaya is fluid enough to move concidrable distances at high eruptive rates .. perhaps the town will be swallowed under Aa?

  17. Thinking out loud so apologies if this is bobbins but I am curious about the imo map of the recent cracks and that the new fissure is at the most elevated point of those cracks.

    This event is unusual in that it is a rifting episod on land that is being fed from below rather than from a magma chamber under a neighbouring elevated edifice, e.g like the recent eruptions in Hawaii and Vatnajokull. In those examples, gravity rules and the likely location of the vent for the dyke is the lowest point of terrain. This event however has now twice produced vents in the most elevated point of terrain. I am wondering if you have a graben like feature in this situation, the centrally slumped section follows gravity and falls towards the “downhill” meaning the faults on the downhill side of the graben are harder to open up as the slumped section is bearing down on those faults. For the uphill side of the graben however, the slumped section peels away, so the most likely point for a vent is always going to be the most elevated fault?

  18. Watching RUV this morning (Early) and I see the twin peaks very active as I the new fissure. No obvious dumbing down of the original fissure and the new fissure adding new flow with gusto!https://www.youtube.com/watch?v=5tGnOydeVUQ

    Remember Milo Thermal that we were watching, waiting for the eruption right at the beginning . Newbies were wondering what the eruption would look like. here is the answer…you can’t really miss it!

    https://www.livefromiceland.is/webcams/keilir-thermal/

  19. So twins are happly living after same old duty they fullfil, one (left) bubbling and the other (right) cocking some pizza in that oven that try to build. Maybe now I do understand the stuborness they have show since the beggings, maybe tha’s why they gracefully avoid leak outside the Geldinggadalur valley, they knew that there will be others and left the Meradalir for the rest of the crowd…

  20. Cerise . Looking at the heights of the twin flares I think they are as strong and active as ever. Remember they are showing over the tops of cones, the bases of which have been covered by layers of spattering, I think the pressures that are forcing the eruption are as much as in the new fissures, we just don’t see the flares from ground level, just the tops. I am wondering if the deep magma has just found and opened another weaker crack in the crust . since the magma seems to be coming not from a chamber that can be emptied, then possibly more fissures will be breeched . This makes further fissure opening, maybe in the direction of Kellir, possible. I watch the occurrence of earthquakes with interest!

  21. It looks like there could be some more small vents in between the first cone and the new cone, the area has started to sink as a graben forms as well as apparently turning into a landslide. Would not at all surprise me if the whole area inbetween the main cones ends up erupting over the next days/

    I expect that over the year the entire length of the dike will erupt at some point, the inflow of magma into the dike at least when it was forming was around 20 m3/s, which is sufficient to erupt at around 50 m3/s when degassign is taken into account. It was going at 5 m3/s up until the past day, now it is at 10 m3/s possibly more, but it still has potential to get quite a bit higher yet.

    • and noticed some light starting to come up inbetween the two vents now… wheeeee.

  22. While watching some clips of the new fissure, I caught a couple of glimpses of the “exit” area of Geldinggadalur valley (behind the cones from the old RUV perspective). Looks to me like it’s finally about reached the highpoint. My guess is that, if the flow from the two cones continues, we’ll see an exit flow from the valley soon.

    Is it known roughly where the deep magma source conduit joins the dike? I’m wondering if we might see more vents open between the current areas and where the magma enters the dike.

    I’d like to thank Albert and this site for the great coverage in this article, which was both excellent and incredibly fast. I’d also like to thank the compiles of the timelapses and other videos, and also the great commentary here. This is definitely the go-to site for anything volcano-related.

    • I think that magma intrusion is somewhere around the tip of peninsula…and Keillir is back head, so of lava is let’s say fluid, any surge at south will send a pressure wave at north. In my pov that’s the explanation for seismic events, both surge from mantle as well as pressure bump trigger cracks, small seismic sorces…now regarding the gap between….yee…all along dike profile lava will breach thru surface accordinglly, also, to fluid law…wherever it finds weak opposition…or old lava tubes?? I start to wonder what about that Hattangy valley that was considered first eruption choice….and yes, as Randall says…some pressure maps will help, GPS…so on

      • Also waiting for an eruption south of Keillir. But as I understand it, the magma intrusion was directly from below and into the dyke that goes from around Keillir southwest passing the first eruption site. Not from the tip of Reykjanes along the transformation fault.

      • The lava flow today… is a bit more runny than Holuhraun.. ( perhaps somewhat lower viscosity) but not very much.. But its 40 C hotter this eruption than Holuhraun

    • The eruption is also… a bit hotter too even if this is not the Icelandic Hotspot thats erupting
      1220 C is eruption temperature of fagradalsfjall lavas… Holuhuraun was 1180 C

      The eruption also suggest reykjanes… is hotter and more molten than I previously realized but the crust is thin… and astenosphere is close to the surface. This eruption is much much hotter than Fimmvördhals 2010 .. but that one.. was a cool alkaline basalt… and made visocus strombolian eruptions like Etna.

      But Holuhraun came from an orginaly much hotter plume source than 2021 eruption… it just cooled a bit on the way up

    • That new cone after a day is as high as the old twins after all this time. Massively more output I guess

      • Output of the new fissure was calculated at 7 m3/s, while that of the original cones being at about 3 m3/s, for a combined total of 10 m3/s. It was at 5 m3/s before so effectively the eruption has doubled.

        It also looks like the output of both vents could have increased even more since the last measurement, the new fissure could be fountaining up to over 50 meters continuously. The quakes close to Keilir are also still ongoing, that area seems set to erupt too. Some point we will see an eruption along every part of the dike. I think it could still go on for years but its too high eruption rate to create a pahoehoe shield now.

        • Around 7:40 one of the right cones (new fissure) slowly collapsed. That was followed by some vigorous fountaining at the same location. After that, visible activity has been subdued. The long term viability of this fissure is not yet proven.

      • don’t forget that the original cones filled a valley…. first.

  24. The new fissure looks so different from the rest of the terrain it’s almost like someone photoshopped it in there lol

    • I had the same thought-it does look like a photoshopped it! It shows Benja we are not alone with our own thoughts.

    • impressive! really puts the eruption in prespective… and the first cones look so ‘untidy’. 😉
      Thanks!

    • The lava in Meradalir is not that far away from the pond. Also: It seems reasonable that the water of the small lake would be found at the lowest point of the plane, making it an attraction point also for the lava. Right?

  27. I watch Randall’s excellent view of the eruption. Can’t help wondering if a lave tube is in progress at certain points as it makes it’s way to the valley.

  28. The steam at the north cone was sending us a message and I wonder now if some new fissures might occur between the cones and the new complex? Someone mentioned this possibility. I have noticed that steam always seems to appear at the two ends of a new fissure

  29. Had a quick watch on the RUV cam, and have the lava path widened ? Even the rapid parts of the channel seems wider than yesterday. And what causes a narrow and rapid part of the channel to overflow? Obstructions or increased flow that does not fit in the channel?

  30. From RUV this morning:

    Landslides between craters
    Rescue crews on duty at the eruption sites on the Reykjanes peninsula reported to the Meteorological Office’s nature conservation expert from the first hour of the night that they had spotted what appears to be a landslide between the craters in Geldingadalur and a new eruption fissure north of them. It seems that the earth has sunk by up to a meter where it is most. Whether this is a harbinger of further changes in the volcanic eruption is difficult to say, but developments will be closely monitored.

    • That’s interesting. These fissure eruptions are well written about, but we are kept guessing what the next move will be.
      Classic action adventure volcano!
      I somehow imagine it getting longer and bigger now.
      But with action and adventure movies, predictability would be boring.
      Reykjanes fires are keeping us on our toes.
      The landslide is one to keep an eye on, but it could be just a distraction.
      It would be cool if the two eruption sites connect, I would not bet on it though, it may well just issue gases and steam. But…

    • What the laymen thinks:
      1. The two original vents (Castor & Pollux) got fed from the north,
      2. Landslide happened (accounting for the quake registered) and cuts of parts of the supply,
      3. => C&P show less activity,
      4. magma in the dike finds new way to the surface.
      Just an obvious idea.

      • There is a minor mistranslation – shocking from Giggle I know – but what bulletin was talking about was that a new graben, a linear sinking in the ground that may be a precursor for a new fissure, was forming late in the night

  33. HVO recently posted a photo of an outbreak from the edge of Kilauea’s crusted lava lake, these had been happening since early in the eruption but have been given very little attention, now I wish there was a video of how the happen. These small rapid outbreaks seem to be the way that the lava lake grows sideways, while the lava erupted from the active vents builds up in a liquid state below the rising crust.

    I have also noticed that Mauna Loa is deflating again, the 4th deflation event since June 2020, and by far the strongest. I think these strange rapid deflation events might be some sort of pressure waves created by the 2018 eruption of Kilauea, the pressure changes may have slowly travelled downwards from the draining of Kilauea in 2018 towards the Hawaii Hotspot and then returned upwards towards Mauna Loa.

    • They call it an ‘ooze out’ but it looks in reality to be a very fast flow, the whole thing is bright incandescent.

  35. The pizza oven is just now at the old level of output. it is impressive much more than yesterday, maybe more than the days before.

    • Yes that was beautiful. I’m glad you kept up. I probably stop for a while to consolidate everything I have.

  38. This morning there is/was a slight snow covering of the area. Now, snow melting between the new and the old vents could be indicative of possible new vents? Of course the temperature differences at the surface should be marginal, but the thin snow layer will melt suddenly when a certain temperature is reached. Maybe some patterns can be observed on aerial images? Plus, flying with the Geocopter over the place is cool anyway.

  39. More smoke on new fissure area… more vents opening?

    • I think its where lava has overflowed and started a small fire, that spot is pretty out of line with the rest of the fissures so I wouldnt expect lava to erupt there, not when there is an existing vent so close. There has been some overflights though so we will know soon 🙂

      It is interesting how much that gully has filled in, the channel formed a tube in the deepest section and lava has just kept flowing over the top and filling it in, its much more substantial now. Its still an open channel at the vent too, not often that an open channel actually flows into a tube, usually its the other way around.

      • Tube at higher eruptive rates too ..that explains the enromous Ionian lava tubes tubes that can be 300 km long.. feed by over 100 m3 a second

        Lava tubes on earth are often small in girth and rarely exceeds 100 km and most are just a few kilometers long

      • The slope there at new fissure… helpt the lava tube to form.. slope channels often form tubes like they do on Kilaueas Pumala pali

    • I’ll ask my daughter to deliver you a pizza. She’s a Pizza Hut delivery driver!

  42. This eruption is amazing almost 1220 C … thats rare on Earth surface… most magmas even basaltic emerge much cooler after stoorage. Most other basaltic magmas on the planet just barely reaches above 1100 C.
    And many evolved magmas are much cooler about same as a well built large camp or bonfire

    • I think they should just have 3 cameras, one to look at Bob, another in the same place to look at the new vent that also needs a name 🙂 and then the 3rd that looks at the lava cascade. There also should in my opinion be a webcam looking down the axis of the dike from the top of Keilir so if an eruption happens somewhere far from the existing vents it will still be seen immediately.

      I think that yesterday was also one of the only times that the opening of a fissure has actually been caught on video in detail, it was already started when they panned over but probably began within a few minutes, and most of it opened on camera.

      • I would say that the videos from Kilauera/Puna a few years ago were more detailed. Lots of footage of the first spatters from cracks.

    • Looks like Gollum and Smeagol vents are in slow shield building speed of effusion… they refuse to give up. Perhaps the previous come complex will be a lava shield after all… ?

      • Hmmm perhaps the previous cone complex will be a lava shield after all… ?
        But the lava is stuck in a valley and is ponding more than flowing out

        • There is not much left of that dale to be honest, the lava pond is not at or higher than some of the original ridge the fissures started at. Question remains is ow much is being put out into tubes out of sight towards the edges of that field. It does not have far to go to two different spillover points

    • A pan/zoom sequence started at 13:19. Watch for the alien being thrown from the new vent just as the camera zooms in.

  44. Orientation question ..

    Looking at the new Meradalir valley view ..

    Two cone “Bob” on the upper left ??
    and
    Larger new fissure cone on the upper right ??

    Is that the correct layout ??

    • That’s my assumption.

      Using a clock face orientation, the original vents are around 11:30 and are roughly above the dirt road that runs up the hill side behind the lava flow on the valley floor, new cones are roughly at 2:00.

  45. Looking at Geldingadalir what is now Cam2 (old Cam 1). On the slope to the left facing the camera there seems to be some slumping and a new gap? Or is this just a water gully visable due to snow and light?

  47. There were several collapses on the vent wall on BOB starting at around 14:07:00 on the time stamp.

    • It appears that RUV added a zoomed-in camera on their north-facing valley view rig….least that’s what I can figure out from various comments/descriptors.

      • Sorry, macusn – this was a reply to Westfjordian, must have clicked the wrong clicky thing.

        • I do that all the time, specially when trying to use my phone. But yes, that aggregate live stream creator said himself in his live stream comments that the 4th “stream” was just a zoomed in section from the RUV1 cam

  48. I think it would be good to see some aerial photos of the area around the new vent, from today. To see how it has developed, from the distant view only the biggest cones seem active now.

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