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”

  3. They are moving really fast now.. another two minutes and it looks like 60 meters or so movement.. that fissure is breaking wide open.and moving quickly towards the cones..

    • I agree, it is lava headed towards the cone, very hot lava

  8. Might be very near Camera 2. See some gas in the bottom left of that feed.

  9. From RUV.

    A new crack has formed

    Clever viewers of the webcams noticed that at midnight a new eruption fissure opened just northeast of the original eruption in Geldingadalur. The Meteorological Office’s nature conservation expert confirmed this to the news agency right in this. The new fissure appears to have been found at the site of the rescue operation.

    • That’s us!!!! we’re the clever viewers.. scoring a first!!! yeah Volcano Cafe !!!!

    • That camera may have minutes left in its live-span only…

      • Time stamp for when it first appears pretty much 00:00:00!!

        • On the horizon right between the old twin cones on the left and the Easter Monday fissure on the right. Plus a cracking view of the new, second lava river down the new gorge. You can rewind the ruv cam on Youtube but not on the ruv page itself.

  15. I recorded the new fissure opening from the webcam – left of screen;

    • wow, thanks a lot.. Volcano Cafe is making news tonight!!!! we’re made a scoop!!!

    • Excellent, well done team! I have been shopping, came back to this, always late to the party… Tomorrow is going to be fun, fun, fun…

      New names for the features now??

  16. one goes for dinner and comes back to fissure. K100 cam certainly is lucky to be where it is. i hope the current view is just change of exposition, not actual exposition.

  17. well, this really makes my later afternoon, watching a fresh brand new 3rd fissure set erupt and send very hot lava down the slope to the lava pond where the old cones are. I think emergency services did declare the area from the 2nd fissure set to the cones as a dangerous area, according to IMO

  18. The view on the mbl camera is both stunning and a little bit terrifying right now!

    • I got almost 6 minutes on simplescreenrecorder and rendering it right now to a video. Will post here.. looks like a scene from hell.

  21. anyone in the office to pan the camera around a bit?

      • ahhh….rats. Yes, you’re right….it just zoomed.

        Need a zoom in on the old cam 1 from ruv for a bit?

  22. Well, it’s no clear how far the mbl.is camera is from the new flow, but if it stops all of a sudden we know what happened. The radiative heat may overwhelm whatever protective cover they may have installed.

    We can watch it happen live…

  24. Definitely a renewed vigour in the original two vents also that seems to coincide with the new fissure opening up. A fresh emplacement of magma into the system possibly?

    • HUGE fountaining from norður vent a couple of minutes ago. Caught me off guard!

  25. There looks to be a duel brewing in that there ‘valley’

  26. Was just about to head off to bed then thought to myself “ooh, best just have a quick check on how the eruptions are getting on…”, first link I clicked on was the mbl.is webcam ( http://k100streymi.mbl.is/spila/webcam0 ) and you can imagine my surprised/confused/excited reaction to seeing lava creeping close across the camera from an unknown source haha! The saga continues eh?

  27. That lava from the new fissure is absolutely gushing into the scene on the MBL camera!

    • This is why we come to Volcano Cafe!!! We love it!! and we made what news people call a scoop! We called in the 3rd fissure breakout at 23:59:57 pm 6-Apr-2021. Volcano Cafe should be proud!!!

  30. ok… remember that burning stuff on the left of the original cam at the very beginning and we talked about it being an extension of the eruption and in line with the vents??? Who thinks we might have been a little premature but still right… anyone? anyone? https://www.youtube.com/watch?v=7-RhgB1INII

    • the fissure must be just to the left of K100 camera. I hope we get lucky and no random bomb cancellation.

  32. Welcome to Earth, 2 billion BC.

    “Martha…Martha, you wanna bring some more of that wunnerful iced tea of yours over here on the porch? Dang, it’s gotten right warm out.”

  33. For all the time spent wondering when/where the lava would fill up the valley and spill out…it’s amusing that the lava’s now flowing INTO the valley!

      • Thanks and sorry, I take it all back after having seen another angle.

  35. A day or so back I half-joked that the disappearance of lava down a hole just north of Gollum (Nordri) was not what the Icelandic geologists said. I reckoned it went down an opening rift and would meet magma rising from the mantle.
    Now, I rest my case. I believe there’s a huge crack under the lava in Geldingsdale, between Gollum (Nordri) and today’s brand new fissure. That’s why the lava dropped down, and I guess it might unzip and start fountaining in due course.
    Watch that space!
    (Experts, of course, are invited to put the boot in…!)

    • I think you are right, not an expert but your explanation fits logic
      The crack is the fissure and it may well get opened up even longer, it probably already is just below the surface.
      Fountains well who knows, sounds right.
      I hope its not dangerous to the rest of Iceland, but fountains of say 300m would be lovely.
      Probably over by Christmas LOL
      Just think of all that lovely drone footage tomorrow…

    • Just so you know what I have in mind:
      Please try not to laugh. But that lava went somewhere….!

      • Well done, Clive 🙂 Makes good sense – and yes, the lava *had* to go somewhere!

      • That is not a bad hypothesis at all, it happened with the opening of fissure nº 2 as well: Output from the twin cones dwindled, fissure opened, then activity went up again. We’re starting to see a pattern here…

    • I believe you are right! Last night I metioned something ‘cracked’ on the mbl-cam at 23:20. It looked like Some lava sunk. Watch it for a wilde, then went to bed cause nothing happened. Just checked in and saw new fissure. Could that moment be a sign? I think so!

  36. So just as the flow rate goes down to 5 m3/s again a new fissure opens, seems that it is less the vents actually declining and more a temporary diversion to feed a new vent. It looks like overall the eruption is increasing.

    Now I think we can call it Chadagigar 🙂

    • Wow, google reduced the image quality, it is 1560×914 pixels, not their reduced version. Sorry about that.

  38. There seems to be a lot more smoke (gases?) being emitted tonight – or am I wrong?

    • I thought this too, but I’d put it down to little/no wind tonight allowing gases to hang around longer. That being said, it does seem that activity in general has also increased so it may be a combination of the two.

  39. Clearly, this is no longer a ‘tourist eruption’. They won’t allow anymore people into the vicinity for quite a while, that much is certain. The potential for serious calamities would be too large.

    At first light the area will look quite different than what it looked like yesterday (Iceland time).

  40. Is that some fountaining beginning in the lava pool between the original cones and the new lava coming down from the new fissure?

  41. The flow rate from the new fissure into Geldingadalir is extraordinary!

    • With regards to your previous hypothesis about the fissure near Gollum:

      Note the glowing from the “oldish” breakout near the base of Gollum….I’d put some money down on your thoughts for sure!

  42. What I’d give to be able to take a slice out of the earth right now and view a cross section of what’s going on a few metres below the surface in this area… 🙂

    • Me too, Sam.. would be most interesting to see! What I wish too, is that somehow we could better figure out when the fissuring actually occurs, as it seems rather silent. Certainly there must be some way to predict this? Yes, I recognize it has not been seen in 800 or so years and this is a rift eruption, not a stratovolcano eruption.

  43. Something is going on downstream from the original two vents, lots of fresh lava with white light on the cameras

  44. Hard to make out on the cams but the new fissure seems to still gradually be unzipping towards Geldingadalur.

  47. The new fissure is definitely unzipping towards the original cones. New lava fountains and a new lava stream can be seen just behind the main lava stream from the new fissure on the Mila cam.

  49. it looks to me as if the lava stream from fissure 2 has branched / divided and the southern stream is now headed down hill towards fissure 3

  50. I think I see some spurting light from somewhere behind the MBL camera as see from the original RUV…?

    • Sorry – should be pinpricks of light, not spurts…

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