Fagradalsfjall eruption 2

After several days of heavy shaking, the new eruption started today. We know very little and are mainly enjoying the view. That there was an eruption is not a surprise, the location perhaps was.

The earthquakes showed an intrusion in the general area of Fagradalsfjall. They were located a little east of last year’s dike, running from the mountains to east of Keilir. Soon, a large range of the Reykjanes fault zone joined in leaving only the western and eastern edges of the peninsula excluded (poor things). However, the plot above shows that the kink (the intrusion) was clearly at Fagradalsfjall. The other regions just responded to the pressure from the centre.

The intrusion had started with some weaker earthquakes at a depth of around 10 km. Here is the original events, from Saturday 30 July showing these weak ones, which were shortly followed with larger shallower events. The rocks below 7 km or so are different from the ones above and tend not to show much activity. The weak quakes signify a more significant event. We saw the magma moving up, in a way we had not seen in last year’s eruption.

After this things moved quickly and by yesterday the magma was reported to be just 1 km below the surface. The rest is history.

We don’t know whether the intrusion infiltrated the original dike from last year. The largish earthquakes suggest it founds it own way up. The eruption started close to the location of most of the activity. It is on the side of the hill next to the northern edge of the Meradalir lava field.

One may wonder whether the eruption actually started earlier. Below the thick crust, much of the Meradalir lava will still be liquid. Magma could have been seeping into it before. But the current fissure seems to be above the old lava field and is therefore a new one. This also shows that the new dike followed the same line as the old one, but offset to the east. The location could have been a lot worse. Lava here will largely cover empty ground in the heart of the peninsula, and of course will provide a new layer on an already existing field. Tourists will have to walk much further though than before. I would not recommend walking on the old lava field before knowing what is going on below you.

Last year’s eruption started very slowly, moved a bit, and became larger after weeks when focussing on a single cone. It always kept a low flow rate, and this helped to keep the lava field contained within the old mountains. The current eruption has been developing faster, perhaps because there was already magma available at the magma collection points some 7 km deep, from where the dikes intrude. However, the limitations which caused a low flow rate last year will still be there. The magma pressure is distributed over a larger area, so it would be reasonable to again expect a slow eruption. The eruption could also be short-lived if the intruded amount is small – certainly we have not seen that much inflation. The Krysuvik GPS showed an intrusion closer to Keilir and INSAR showed a clear dike, but the movement was much less than last year. However, it the eruption taps the existing reservoir, it could be more extensive. At the moment, we can only guess.

It is again notable that the eruption does not make use of old conduits. Every eruption here seems to create its own fissure (later to become a cone). The region is unpredictable. In fact, if ten years ago you would have predicted something here, you would have gone for the volcanic centres on either side. Fagradalsfjall, lacking hydrothermal activity or any holocene eruption, would be not be high on the list.

What is clear now is that the race for the next eruption has had a winner. After 800 years of solitude, Reykjanes has won twice in two years. We can declare a new era of Reykjanes fires.

And now we are waiting to see what Grimsvotn will do. After all, it also is on a yellow warning.

Albert, August 2022

update: fissure map fixed, now with a more correct (but probably not yet perfect) location

125 thoughts on “Fagradalsfjall eruption 2

  1. Thanks Albert, I saw the lava on facebook and wasn’t sure if it had got confused with the previous eruption – very interesting 🙂

  2. Thank you Albert. I enjoy the dull metal hammering sound that comes from my pet theories being knocked flat. 🙂
    This will be another fascinating eruption. Let’s hope the cameras settle into position swiftly!

  3. The fissure is drawn too far to the east. It’s along the western side of the ridge coming down from Meradalahnúkar.

  4. Looks like it is thankfully in a relatively safe place, though as you say hopefully the wandering tourists don’t walk on the old lava field, would be good for the Iceland authorities to get ahead of this though I doubt tourists will be allowed (as they shouldn’t) just yet.

    I wrongly predicted Grimsvotn but I think it’ll be soon too.
    Also I’ll predict that a few more rifts open up, likely slightly further northeast.

    • I think those other rifts might be for later eruptions, there will eventually be a whole line of large cones and maybe some shields going all the way from Natthagi to near Keilir, but will be some years before it shows fully I expect. Something like on Lanzarote, maybe even a comparable volume but it will take several decades, so more like Pu’u O’o but with many locations.

  5. Thanks, Albert. Fantastic work getting news, background and analysis up so quickly after the eruption started.

    Two comments:
    1) I read a report on one of the Icelandic websites (RUV, Visir, or mbl) quoting one of the well-known geologists who thinks that we could be in for a bigger eruption than last time. Apologies, not only can I not remember the source, but I can’t remember the argument for the view, either. But in the end, as you say, we don’t know.
    2) The eruption site: how confident are we that it is where the map shows it? Piecing together some maps and photos (eg here: https://twitter.com/StefanEiriks/status/1554854025094483970/photo/1), I was wondering whether it might be two “prongs” to the West of where it’s marked on the diagram in your post: the long, slim one below the reddy-brown patch. That is, the valley W of the westernmost of the three Meradalurhnukar peaks.

    • Re i) I saw that on RUV.is. I think they were basing the estimated volume of magma on ground uplift.

    • Source RUV.IS and google translator:
      “The eruption that started today is probably five to ten times more powerful than the eruption in Geldingadälar last year, says Magnús Tumi Guðmundsson, professor of geophysics. ”
      2021 eruption when it stared, for comparison:
      https://youtu.be/Q5VnL9pAbe0?t=19

    • I read that a prelimanary estimate is 10x the flow rate of the previous eruption.

  6. Many thanks for getting this post up so quickly Albert. I was just going to ask if anyone had any links to good maps and here they are coming aplenty, Thanks also to all you posters who are updating with links to videos and other info. Volcano Cafe is always on the ball so quickly. And looking at the topography from the air I see now why Jesper spoke of a rootless lake. I had assumed the fissure was at the lowest point.

  7. I see the vegetation fire west of the Fagradals crater is smoking again.
    Perhaps there is some intrusion heat coming up there, too?
    Or the Brussels spouts have been left on for a few hours too long…

    • Excellent! Thanks for the link. It’s interesting to watch the cone development!

      • Clive, it may have shrunk, but since the rift in on a mild tilt, some of the lower elevation outlets may be under lava now, rendering them invisible. Is that possible?

  8. Great! Now no one will be able to talk about some actually dangerous volcanoes.

    • Very hard to beat Iceland on volcano-appeal. It has the scenery, the culture, tourism facilities and no snakes. I actually prefer my volcanoes to be non-dangerous – but that is not something we can control.

        • It is said you’ll have a two hour hike in, IF conditions permit, and the terrain is demanding. By 8/5 the accessibility may change drastically.

      • For volcano tourism, Iceland is the best location and this would be a good eruption but in terms of engaging discussion? This current eruption is as bland as bread, the first eruption was a bit engaging but in my opinion, the reaction was overblown. Over 21 articles and entire comment sections dedicated to one small eruption? Taal’s dangerous activity and Etna’s spectacular eruptions were sidelined for Fagradalsfjall and now Chiles-Cerro Negro, Taal, Sakura-jima, and potentially more might all be put to the side for this unremarkable eruption

          • I totally agree with you a320. In Iceland we get to see actual footage of a real volcano and also no anyone injured in these eruptions it is usually the persons own fault for foolish behavious. THAT is the tye of volcanos I love, not the ones that engulf villages and destroy the lives and livelihoods of the poor people who have no resources to flee a dangerous area,

          • So much gas coming off the vent, seems much moreso than last year’s eruption. Looks like the wind shifted in the past few minutes too and filled in the area near the cameras.

          • So odd, not sure why this comment was posted up here. Pretty sure I entered at the bottom of the page.

        • There was a good bit in the comments from one of the Nyiragongo articles about Chiles – Cerro Negro and the surrounding Dacitic volcanism of the area. Hector, Chad, and a few others had some really good and insightful comments, especially about its potential magma chemistry and what other nearby systems have done.

          Was actually really happy to see everyone dive into it for a bit.

          Would love some more discussion of Sakurajima and what it’s doing. I really haven’t seen much on it, anywhere. The increase to alert level 5 was confusing given it looked like only moderate vulcanian explosions, but I gather it was lobbing volcanic bombs distally enough to threaten the vicinity?

          • If someone wants to see a particular volcano getting attention it is just a matter of posting comments or even articles of this volcano, as long as one other person interested in this volcano shows up then we can have a discussion.

            I sometimes get disappointed myself, that there is no one for me to deeply discuss Martian flood basalts, which have the biggest, most powerful eruptions in the Solar System. I’m sure however that there are other people interested in Chiles-Cerro Negro and such volcanoes, as was seen in the Nyiragongo post, back there I learned from Cbus insight into the silicic volcanism of that area, and Glenn Rivers made me ponder into some interesting questions.

            No topic however is going to match the interest on Iceland or the Canary Islands and that’s just the way it is. Even with Hawaii there might be a lot of discussion sometimes, but it is very few of us that make that discussion happen. There is nothing wrong with this. It is natural that the interest would be directed towards volcanoes closer to home, that are being recorded by several webcams at the same time and last long enough to calmly watch them erupt.

        • Tallis
          Of course you are right.
          Any of these would cost many lives and be sudden, short and destructive.
          However in C21 what counts is good coverage by a reliable source.
          Iceland.
          Which is wrong, as you say.

        • Y’gotta understand that this blog is European-centered. I’ve grown to accept it–and learn from it–but I understand your view nonetheless.

          Depends on where the action is, to an extent, too. Myself, I’m getting bored with Kilauea’s dribbles, and I feel I might not see another audacious ERZ eruption in my lifetime.

          • We know the reputation and the majority of the admins live indeed east of the sea. But we do try. There are twice as many posts this year about the rest of the world as there are about Europe (not counting non-geographical ones such as the Earth’s mantle). Hunga Tonga was spectacular if brief. Effusive eruptions last much longer, so get longer attention, and these are called ‘Icelandic fires’ for a reason.

          • There will be much more ERZ eruptions, as soon as the summit is filled up enough that the pressure will force magma into the intrusive complex of the ERZ it will be erupting in no time. There are two, one from Mauna Ulu to Kalalua (east of Pu’u O’o) and then another that is roughly centered on the mid 18th century shield of Heiheiahulu. I think most of that complex formed in the 18th century, the complex that exists east of Napau is probably entirely since 1950, and that which is west of Napau is maybe about 1000 years old but grew in the past 70 years mostly to the east as said above.. They are what allows large shields to form away from Kilaueas summit.

            Kilaueas summit is boring now in a way but relentlessly filling, at its current rate it can overflow the entire caldera by 2030, assuming the ERZ connector doesnt take up long before, which is unlikely. The intrusive complex under Heiheiahulu is the one to watch, it is the last one to become active but when it is, it means the whole volcano is full abd ready to go caldera. It is where 2018 started.

    • We have webcams (plural!) pointed at lava continually flowing out of the ground, together with drone footage and live reports from people standing right next to the thing. That is… enthralling.

      The problem with the dangerous ones is that things change sllloooowwwwlllyyyy if at all. Little is immediately interesting until they go off (or are just about to). Plus, the data is often sparse and incomplete, making any forecasting or understanding even more of a shot in the dark.

      I love talking about the lurking beasts and imagining their awful power, but as a volcano nut, there’s just something about watching red stuff come out of the ground. I can’t get enough.

    • If I don’t comment about a given volcano, it’s usually because it is unknown to me, so I’m reading the views of others who DO possess that knowledge… Or maybe because it is so remote from me that it has no bearing on my life (fickle, but honest)… Or a dozen other reasons.
      Tallis, I can tell you that I know next to nothing about ANY volcano, but from what little I know I consider Taal
      in particular to be very worrying. But as of this moment in time I have nothing of value to contribute to any discussion on the subject.
      Nor do I have contacts in the vicinity who need me to give them any tip-off (they’d probably already know), or feed me information from the locality.
      In fact, to a large extent I look to you to keep me updated, so please continue doing what you do.

      But in defence of this Icelandic event, I don’t think it is in the least bit unremarkable. The opportunity such a “safe” and accessible eruption gives for study is surely not an opportunity to be missed. It may not be Toba, but from my point of view, that’s a good thing.

  9. The valley is getting heaped up with the lava from the eruption. I suppose it can only go south and join the main outpouring from Fagradalsfjall.

  10. Pingback: Postcard from Fagradalsfjall – Zoopraxiscope

    • Whats the temperatures of this lava
      In daylight the camera color is not good at all .. Althrough looks clear yellow now in evening

  11. Civil Protection: please don’t go to the eruption site just yet!

    Only 10000 show up (estimated number).

  12. I am amazed at how we keep missing the exact moment when the lava bursts through the ground and starts the fissure eruption. We missed it on the first eruption and we missed it here. Are fissure eruptions in Iceland stealthy? I do remember that time when the north fissure opened up near noon hour right under the feet of the people walking in the area, fortunately no one was hurt.
    Questions:
    Why is the last 1 km of magma ascent quiet?
    While reactivating through the old fissure complex, a new fissure formed east, does this suggest that the old fissure conduits became as hard as the neighboring rock around it? One would guess that old vents get reused, but this doesn’t seem the case for fissure eruptions.
    Did the vapor and steam coming from the old cone give a reliable signal to the nearness of a fissure eruption?
    Just some things I wonder about

    • The Keilir camera caught it, although at quite a distance. Smoke/gas formed a blob, then another next to it, expanded into a cloud and then the fissure unzipped.

      • Actually I re-recorded the Mbl.IS cam and it started at 13:15:52 local Iceland time from the steam plume which becomes visible. I do have the mkv video saved of this event.

    • RE:”I am amazed at how we keep missing the exact moment when the lava bursts through the ground and starts the fissure eruption…” There’s a video of that on YouTube. You’ll have to search it. I suppose there were those on ‘BobNation’ who watched the tube 24/7. I have a life.

  13. Looking at the maps, the lava seems to be confined in a small valley. If the eruption continues, it can either flow over the old lava field and add to Meradalir, or it can go north over quite a flat area. Nothing is particularly at risk at the moment.

    • What is problematic is the actual flow rate of the new lava. This eruption certainly looks more effusive than the last. I saw a quote of 5x to 10x previous rate. How long does it take to get a good handle on the flow rate?

    • What I wonder about is that the old conduits are not reused. Is this due to cooling and hardening of the magma underground? It would appear that a lot of energy was used again to replow a brand new fissure. It is remarkable that the fissure doesn’t even care if a hill is in the way, the split goes partially up the hillside.

      • I think, old conduits can be reuse only for ash and stratovolcano, but not in MAR fissure eruption. Look on google map Reykjanes area. There are many old fissures with small craters. Its means that eruption appears because the land is spreading and give to magma easy ways to go out, but recent previous eruptions filed this ways, and new eruptions develop in the vincity not filled by cooled magma.

      • My thought precisely.
        The most obvious answer is that its not lava pushing up that breaks the rock but the fault opening. In this scenario the old eruption has removed the strain so has no energy to reopen. Further along the fault, where there is still significant stress, the rocks eventually open up and the lava simply fills the gap, and if there is over pressure, erupts onto the surface.
        This is not to say that a significant part of the stress is due to a big blob of hot rock underneath and doming the area due to buoyancy, but that’s more at depth.

  14. 4 different live cameras all in one place. https://eruption.acme.to/

    I just saw people in the foreground walking around the edge of the lake. It really gives you a good guide to judge the huge size of the lake.

      • Thanks. My own first guesstimate was half that, based on the area covered but I used a low thickness of the flow of 1 meter. The fissure follows the intrusion and swarm of December 2021 (seems so long ago) so I guess the set-up was already there. So no earthquakes at this location and a fast start. It may settle down to a lower value for the flow rate

        • Interesting, the lava thickness is already 5.9 meters. I guess it is hard with limited camera angles and rough visual estimates to determine thickness and flow rates

  15. Thanks Albert for the super quick article. When it closed down last year I thought we’ll that’s it for a decade Well glad am wrong ,viewing the 2022 eruption it feels am at home.The landscape familiar,local names familiar..it’s so good. Well as long as it is ‘people friendly ‘ .I imagine that the Icelandic tourist industry will be stoke.

  16. Eldgos í Meradölum – flugmælingar sýna hraunrennsli upp á 32 m3/s fyrstu tímana
    3. ágúst 2022
    Í dag hófst eldgos í Meradölum, á um 300 m langri sprungu sem liggur í NNA upp í hlíðar vestasta Meradalahnjúksins. Sprungan er um það bil einn kílómetra norðaustur af megingígnum sem var virkur í gosinu Fagradalsfjalli í fyrra. Það gos stóð í sex mánuði frá mars fram í september á síðasta ári. Staðsetningin fellur vel að því að gossprungan liggi yfir suðurenda gangsins sem verið hefur að myndast í jarðskorpunni undanfarna daga.

    Volcanic eruption in Meradöl – aerial measurements show a lava flow of 32 m3/s in the first hours
    August 3, 2022
    Today, a volcanic eruption started in Meradälur, on a 300 m long fissure that runs in the NNA up the slopes of the westernmost Meradalahnjúk. The crack is approximately one kilometer northeast of the main crater that was active during the eruption of Fagradalsfjall last year. That eruption lasted six months from March to September last year. The location fits well with the fact that the eruption lies over the southern end of the tunnel that has been forming in the earth’s crust for the past few days.

    Here is a snippet from the post of the lava effusion rate etc

    • Welcome! First comments always get held back by the demon-in-charge, in a ready-made dungeon, for release by an admin. That is why the delay. Future comments should appear without delay

  17. I love the safer eruptions too but I will get chills looking at the caulderas. From Toba, Tambora and Rijani. My mind can just imagine what ultimate hell they unleashed on those living near. We are lucky to have these to view and delight in nature. I hope we have a long, long time of these because one of those others would combined with weather uncertainty be devastating.

    • Forming a rootless lava lake
      Somehow the lava is quite viscous and Aa like

      • Might be stuff that was in the dike from last year, at least in part. It is also erupting in a flat area so hard for it to flow away

      • It adds to the existing year-old lava lake.The most likely flow path of the lava is back up the old flow field and into Meradalir. Escape to the north followed by westward flow around the Fagra plateau is also possible but requires a bit more altitude

      • Coud it get heavy enough to break the crust on the earlier rootless lake ?

        • I dont know if that lava really ever was a true rootless lake, it only ever partly foundered a couple of times and that was when the lava changed course in July to run directly into the valley at high speed, and following that the majority of it was buried by fast a’a that seems to have not had trouble flowing over it. Probably there is not as much liquid lava now, it has been some 8-9 months, the lava was not as thick. Probably new flows as opposed to reactivated older ones.

          If old lava is pushed out it will be viscous a’a

  18. Some nice close up footage of the fissure from the Reykjavík Grapevine newscast on Wednesday afternoon:

    https://youtu.be/rQI1Ws572gE

    As usual with Reykjavík Grapevine newscasts, the host Valur Grettisson is gleefully effusive and the videography (including several drone shots) is beautiful. As a bonus, at the 12:50 mark Valur interviews some young geochemists (or perhaps grad students) with the University of Iceland while they are collecting samples.

  19. I can’t help myself…
    A timelapse from one of the MBL IS cameras.
    Last time I ran into copyright issues, so unless I get permission this will probably remain a one-off timelapse from me.
    https://youtu.be/CUS6iLNtxb8

    • Looking at today’s live mbl footage, I think the red contour line has already been reached. Comparing with the early footage from lunchtime yesterday, that’s a lot of new lava.
      And Virtual’s timelapse shows this in awesome fashion. Bravo Virtual; encore, encore!

  20. So much gas coming off the vent, seems much moreso than last year’s eruption. Looks like the wind shifted in the past few minutes too and filled in the area near the cameras.

  21. It looks like because the eruption started in a depression and flooded itself quickly, this time around we might actually get a proper shield forming. Of course the lava might also break out into Meradalir and drain the lake a bit, with maybe fountains getting taller after. But with 30+ m3/s effusion rate it is at least unlikely the lava is going to stay near the vents for long.

    Question is how long can the effusion rste hold, it might very well be that the feed rate from the mantle actually is this high, the dike in 2021 did have a fill rate of something like this. Even if not though and it drops to the same as last year, this intrusion isnt as long, and near vertical, from the deep source, and higher rate will tend to cause more erosion of the vent so that a conduit might form quickly. If this evolves into something like 1980s Pu’u O’o I wont be entirely shocked, last year was similar and this is much stronger.

    The fact the flow rate is still the same after almost a day is a good sign I think 🙂 if there is no magma chamber then this has to be at least close to the deep supply rate, which is probably very high at present (probably higher than the rest of Iceland combined right now). Question now is if this will put a stop to intrusions near Grindavik for a while, it is not unreasonable to think the deep sources of all the Reykjanes volcanoes are interconnected, just that their surface expressions stay separate.

    • So “shield building” in this area would be individual dike intrusions producing monogenic rifts and vents, but over time having their flows stack enough to build up the land?

      Is it possible for a proper conduit to form here that will erupt sequentially (separate intrusions from the same vent)?

      • I gather that would probably also need a static magma chamber. If the source is deep it makes sense every intrusion pops up in a different spot.

      • That has not happened since the early holocene. It doesn’t really do shield building at the current time. You can get multiple eruptions from the same fissure/dike. In the future this eruption would be seen as a continuation of last year’s event, just shifting the eruption outlet to more convenient site.

        • Wow that’s so true!

          If this flow were being studied hundreds of years for now it would be seen as part of last year’s flow.

          Just like so many past events at other volcanoes that get labeled a sequence of eruptive pulses over a short period of time.

          That just clicked. Perspective is so important.

          Thanks.

        • To be fair Fagradalsfjall has also not erupted since the early Holocene 🙂
          There was an eruption on the mountain 8000 years ago but that seems a part of a different fissure swarm that could be part of Svartsengi, not related to what is causing the eruption now.

          There actually have been shields on Reykjanes more recently too, Leitinhraun in the Blafjoll near to Hengill is 5400 years old, and Krysuvik has a shield that is broadly similar age, they are both middle holocene at earliest. So shields are possible now just not likely.

          It does also depend on where the line is drawn, last year is shield shaped and if the cone collapsed into the conduit at the end it would be a proper shield. The large flows from Brennisteinsfjoll in the middle ages made shield-like formations, only they are made of a’a not pahoehoe, from episodic overflows. I think that still counts as a shield, and is most likely what we get here.

    • Are you soure that the deep supply in Vatnajökull is not bigger ?
      Well the crust there is much deeper there and there are large stoorage regions and the supply also goes to shallow chambers, but most goes to rift deep stoorage in Iceland

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