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

Related posts

687 thoughts on “Reykjanes surprise”

  1. Zoom sequence on the lavafall camera starting at 15:27. Looks like some of the flow has become entubed to me.

  2. Please refer to the cams as cam 1,cam 2a, cams 3- and 1b+, 3R, epsilon* and dK2. Makes it easier to follow.

  3. I came across this scientific paper which offers food for thought, particularly figure 3. Is there any similarities with present events? “Oblique rift opening revealed by reoccurring magma injection in central Iceland” https://wenbin16.github.io/paper/Ruch_2016NC_oblique_graben.pdf

    I would guess with careful SAR mapping, we should be able to pick up on the curent graben formation and progress.

  5. Pyrotornado moves right to left at 16:56 on the Meradalir Camera, forms about top middle of the lava field

    • 17:16:50 pm shows another one, I saw 1 other one, a bit smaller form, after crossing the hot lava field.

  7. It’s going to get a bit busy in Meradalir if the lava from the original cones heads that way too.

    • That’s a good atmospheric run. These drone videos are very good, the drone in general has certainly made headlines this eruption.
      We are lucky positioning wise, it is relatively speaking “accessible”, Iceland is not usually as forgiving. Also time of year…

    • From about 6 secs into the video for the next few seconds, we can see that there is no thermal heat between the two cones and the new fissures, along the underground dyke as was surmised by a pattern of melting, the snow cover looks undisturbed.

      • I need to add this now – The magma near the surface

        “The cracks are visible from the surface and are about one meter deep and heat rises from them,” says Einar Bessi Gestsson, a nature conservation specialist. No magma can be seen in the cracks and so far no gas has been detected.

        so from afar the drone pictures show no evident melting as what we would expect, but up close, heat is coming up.

  9. Iceland is doing Iceland.

    Two small swarms of magmatic earthquakes recorded deep in both Katla and Oraefajokull. The ones near Katla occur in an unusual spot, far outside of the caldera, which also had a swarm several years ago. This means both volcanoes are receiving new magma now.

    Also the earthquake swarm SW of Keillir continues. A potential site for an eruption if pressure remains.

    • Katla haves a much greater eruption potential in eruptive rates than the current show
      But Katla wont be a long lived show If it erupts .. Summit Caldera eruptions are very powerful But only last a few days

      • With the potential havoc that Katla is know to be able to create downstream, and the ashcloud that most likely will disturb the airspace. I think most people will be happy with only a few days.

        That being said, the weather better good when it happens, so that we can get some awesome footage and data for science.

        • at least if there is going to airspace disruption, best get it out of the way when not many people travelling

    • Man, out of all of Icelands’s volcanoes, this is the one I hope to never see erupt. That will be a mess.

  12. On the mbl. cam-sudri’s sprung small leaks on the flank to the right of the lavafall

  13. so after all the pizza oven start to deliver its goods! round and jusy like a good pizza, a brand new lava pond, deep, full of stuff leaking with a lot of tomatoto souce like…you guess…LAVA! Right now I cannot and didnt want to compare the twins powers….who’s who? who’s cersei who’s jaime? starks are the icelanders for sure…where are the dragooonns? is Katla the mother of them? while the others are fissure openings and the wall is made of volcanism knowledge…after all the winter is comming!

  14. Loving the split screen on the ruv website. Seems like the pressure is being spread out now and we might continue to see further outbreaks due north east.

      • the right vent start to burst lava rom two surces…one deep into the oven and oone huge burst head from the ridge of lava flow…that’s interesting.seems like two vents head into one pool

  19. I’m missing the action after my move, thanks to no internet connection, courtesy of the prdvios owner doing some sort of dodgy connection in the main socket.

  20. https://twitter.com/krjonsdottir/status/1379500454959321096
    Amazing #InSAR from Sjonni showing localized deformation surrounding the new fissures. Importantly, no shallow deformation is spotted anywhere else, meaning magma is likely not close the surface elsewhere in #Fagradalsfjall.

    InSAR data of the eruptive fissure opening on 19 Mar. & 5 Apr. southwest of Reykjavík, showing similar ~10 cm displ. towards the descending radar (i.e. SE/up displ.) southeast of the dike opening, but less displ. northwest of it (where NW and Up displ. tend to cancel). @ESA_EO

    • Thanks, this answers one of my science questions very nicely, and probably answers the GPS displacement vectors also (meaning hardly any movement except near the fissures, with orthogonal displacement)

  21. I really like how the river has split up into several smaller rivers (before joining again), but it looks lke we might get a second big river/lava fall (The red line)

    • It’s very close to doing that now, there is a red flow extending further along

  22. I think there are a new vent opening to the left of the most far lava fountain…

    • … Luis, there is a car driving on the Meradalir webcam (on the mountain to the left) …

      • Yes… lol when i saw it was a light side by side with the far vent… i feel stupid!

    • Is that a new vent half way down the lava river, or burning vegetation? There’s a lot of smoke.

      • At the bottom of the braided lava river, on the right, partially obscured by the ridge. There’s a lot of smoke for it to be just degassing or burning vegetation. Eye of faith can see low level fountaining?

        • Looks to be in this dark brown depression, I guess it is the vegetation in the area that’s burning. However let’s be optimistic and say that depression is a small graben/rift that now is open 😉

        • Guess that would be the wrong place. At least if we believe in a rectilinear dike. Most probable place should be between the two fires (left ridge on the old RUV cam). Apropos, the mbl cam stands not far from that spot. Hope they can remotely turn that one in case a new vent comes up.

    • I checked the K100 camera on the old cones, the lava looks hotter there too and more energetic compared to about 3 hours ago, (assuming no one monkeyed with the saturation/gamma on the camera) as it is showing white hot now. The south cone lava level has noticebly decreased, closer in height to the north cone now. (21:50 pm 6-Apr-2021)

  26. The stream of Lava on the right is now much hotter and moving faster than the other stream on the left.

  27. A lot more activity from twin peaks and new vents. Also from helicoters. They seem to be flying very close to the new vent. I too see smoke towards the end of the lava flow. I think it’s burning vegetation. but hey! Who knows? The whole scene is being very closely monitored tonight. The new vent looks fierce.

  28. “A new survey of the lava was done today, 6th of April, using vertical aircraft photogrammetry. The results indicate that lava flow is very minor at Geldingadalir and the average flow rate since yesterday in the new fissure is 4-5 m3/s. The total flow is estimated as 5-6 m3/s. Apparently, the increase seen yesterday was temporary. The eruption intensity is therefore similar to what it was in the days before opening of the new fissure.”

    • it gives the feeling of actually being on the edge of flowing lava.

  32. Nice outbreak on mbl.is now as well. Maybe its pining for Meradalir.

    • Awesome colors. Also the other vent did zoom out, front advancing.

      • I wish the Meradalir camera would zoom out or pan left a tad so we can see it cascading down the hill better.

  33. Apparently, lava is also flowing from the new vent towards Geldingadalir and the two can merge as soon as tomorrow.

  34. If you go to the RUV Geldingadalir camera you can see some SAR people, might be looking for someone?

    • There’s someone flying a drone, it can be seen quite clearly on the meradalir cam. Here’s a screencap from 22:23+ people with lights in the green circle, drone in red.

    • Either that or they are making sure everybody knows they are there… so no sneaking into the area.

  35. If you rewind the Meradalir RUV feed to 20:51:25 you will see a person walking on the west side of the rivers. From this view it looks like he is within 100 feet of the perched lava river. I believe this is where the new Lava river is now flowing. Hope they got out of there.

  36. Wow something just cracked at 23:20 on the mbl.is cam. Not your average spillover/breakout. Nice!

  37. Looking at the Meradalir RUV feed it appears that the lava flowing into Meradalir has changed paths and will very soon find a new route. Should be fun to watch a new lavafall being created.

    • sorry, it was at 00:00:08 am when the white spots appeared at the top of the camera somewhat in the middle.

    • Looks indeed like a new one. The place would fit very much to the predictions. Again exciting …

  45. I believe a new fissure is starting, 00:00:08 am when I first saw the light in the RUV2 camera, and the flickering and subtle flaming now gives strong hints that it is a fissure, not a flow.

    • Yeah. The right spot. Not far from the mbl cam, which alas is looking into the wrong direction …

      • How can we back up the RUV1 camera to see the exact moment when the fissure occurred? my timestamp is 00:00:08 am when I saw it.

        • Amazingly, I got 23:59:59 in the moment the first glimpse of the new fissure appeared on the stamp in the left bottom corner.

        • 1 have it starting at 4:07, hope it is not just a new lava stream from the one new(old) vent heading towards Geldingdalur(sp?)

          • I thought this first, too. But you can actually see the eruptions and as far as I can see, the fire is on the ridge. Also, this is exactly the place where we expected a possible new fissure.

  46. Can anyone read the sieismographs? What does the quakes show?

  47. Move the camera to the left a little operator of RUV camera 1, please

  48. Lol..and they were going to open the area tomorrow because according to InSAR data suggested magma was nowhere close to the surface in that area..

    Woopsy

  49. Given that the mbl cam has the vents slightly offset an extended fissure should be east of the cam

    • That’s clever. The cracks weren’t perfectly aligned though, I think, …

    • They are moving, in about 3 minutes or so, another 10 meters or so to the right.. are they going to connect with the old cones? Pretty good movement on opening up… we might have a lot of runny very hot lava soon.

Comments are closed.