The Hell Machine

Guest post by Chad

The three musketeers, firing away

As is now abundantly clear, a new eruptive cycle on the Reykjanes Peninsula has begun. While an isolated eruption did happen in the ocean off the end of the peninsula in 1783, there has not been an eruption on land since 1240, today 781 years ago.

The eruption ongoing now has ratherbroken the regular cycle of eruptions at Reykjanes. Normally those begin at Brennisteinsfjoll and go west over a few hundred years, but this vent is on Fagradalsfjall, a mountain right in the middle of the peninsula. This area would not be expected to activate for at least a century yet, but here we are, watching the camera religiously as this new volcano grows before our eyes.

The magma is being generated at a great depth, nearly 20 km or twice as deep as normal eruptions in this area begin, and by mantle that is nearly totally melted to result in a lava that has a very high concentration of olivine. This sort of basalt even has its own name, picrite, and it is the closest thing to the ancient komatiite lava that erupts on the Earth today. This has been interpreted as a possible case for a shield volcano to form at, something which has not happened here for many millennia, but I think there are rather more profound implications for this. The magma is fluid and extremely hot, well over 1200 C, and that is enough to allow both physical and thermal erosion of the interior of the conduit, which will serve to only allow more magma to flow, in a compounding effect. Direct mantle eruptions are rare, but one that is currently ongoing if hard to observe is going on under the ocean near the island of Mayotte near Madagascar. It is not particularly intense, but since it began in mid 2018 some 5 km3 of lava has erupted to date.

The magma for eruptions like this is created by decompression melting as the pressure drops, a self feeding cycle that is limited only by the rate of mantle flow to the area. It is a self sustaining machine, the Hell Machine as I like to call it.

Hell Machines are a rare sort of eruption. Like said above they are perhaps best categorised as some sort of hybrid between a shield volcano and a lava flood fissure eruption. The eruption rates may be sustained at a relatively high rate for a long time, well above the rate seen in the formation of shield volcanoes but also never getting to the colossal rates seen in the big fissure eruptions, at least not for any long duration.

Mayotte is an example of a Hell Machine that is erupting now, it is in the deep sea and it may be that most such eruptions are, but there is a historical eruption like this that occurred on land and it offers some tantalising clues.

On the 1st September 1730 an eruption began on the island of Lanzarote, in the Canary Islands. It was relatively large, creating a cinder cone that was ultimately named Caldera del Cuervos, as well as over a few months the similarly sized Caldera del St Catalina and Pico Partido cones. This constitutes what would have been a typical if somewhat larger than average eruption in the Canary Islands, but we now know this first eruption managed to set off the Hell Machine. Eruptions continued into the next year, though it had declined from the initial high rates as expected, the flows were still fed at an impressive volume to sustain over a year. Submarine eruptions well off the west coast and going up all the way to just inland beginning in June of 1731 marked the completion of the hell machine, it was now in full working order, and eruptions marched eastwards back onto land to flood even more of the island. Observations after this are poor as few inhabitants stayed beyond this point but the eruptions continued into 1736, erupting some 5 km3 of lava, constituting the large majority of the volume of all eruptions in the Canary islands in recorded history. Lanzarote has no active central volcano, and has not possessed one for millions of years, the eruption of 1730-1736, or Montanas del Fuego as it is known locally, was fed out of the mantle directly by extensive melting under the base of the crust. Perhaps most notably, all the eruptions from the late Pleistocene and Holocene on Lanzarote before this were on the northern part of the island, the area where the Montanas del Fuego eruption occurred had not been volcanically active for possibly several tens of thousands of years or more, a certain similarity it does share with Fagradalsfjall.

Lava fields on Lanzarote. Source: Becerril et al. ,Assessing qualitative long-Term volcanic hazards at Lanzarote Island (Canary Islands), 2017 Natural Hazards and Earth System Sciences, 17, 1145-1157

The Signs

The first sign of a hell machine is that the eruption is persistent and erupts out of the mantle directly, something clearly the case already. An eruption should also be a rifting event, where the rift is kept open by new magma, and this also seems to be happening, as a dike has formed within the crust going from less than 2 km depth down to at least 7 km, with possibly many feeding points below this that are not resolved. The very high temperature of the lava will also serve to enlarge the pathways, something that may take longer than a week to become evident but which is expected.

So far our eruption is quite small, even tiny, but it has a big future. The first obvious sign could be that the vent increases in output, or that it stays constant but another vent opens. We may already be seeing this, as the vents are rather a lot larger than they were to begin with, and the output appears to have increased. Deflation is not observed along the dike either, which would suggest the eruption is being fed by continued decompression melting in the mantle, a process that may increase accordingly with the eruption rate and set the hell machine in motion.

What will become of the Reykjanes peninsula if this occurs? Perhaps the most direct consequence is that land within perhaps 10 km of Fagradalsfjall is potentially at risk. There is no danger to Reykjavik but Grindavik may suffer if not from the lava then from the gas emission. The effect it will have on the normal Reykjanes cycle is also unknown, most typically the section of the transform fault at Brennisteinsfjoll is the first to go but this time around the section going through Krysuvik was set of by the recent intrusion, leaving Brennisteinsfjoll in a precarious situation. Decompression melting at Krysuvik may well have already begun now in preparation to its awakening, and Brennisteinsfjoll could wake up rapidly following its eventual quake. Eruptions here will resemble those from the Reykjanes Fires, but taking a back seat to the lava flood that is just beginning now at Fagradalsfjall. We are watching history creating itself.

Perhaps this will not come to fruition, it may turn into a shield instead, or even stop. But with all the signs it is looking like the future is grand for the new little volcano.

Chad – 2021

859 thoughts on “The Hell Machine

  1. Shield volcanoes on the Reykjanes Peninsula are though to originate from small fissures, which eventually coalesce into a main vent. Think it is still early days to say whether or not we are going to see The Fagradalsfjall Fires or a shield. Guess it is the wrong lava type to form a new Hekla?

    Mind you, a brand new shield volcano on your doorstep is going to be a bit disruptive, at least while it is forming. Fagradalsfjall was contained as a table mountain by the then ice-cap. There is no such constraint now.

    • Yes, that is the problem right now it is all very early. Back in 2018 at Kilauea the eruption still looked tiny by this point, fast forward a month later…

      I should also say I wrote this back in March, so it is good to see at least one of my predictions has come true, that more fissures have opened, and stayed open, without killing the first vent 🙂

  2. Interesting post, Chad, thank you. & thank you to everyone for the other Reykjanes posts.

  3. A timelapse from the Meradalir ruv camera only.
    First part is just to give an idea of the weather and the lay of the land, and I like the colors 😉

    Around 23 it’s more or less continous with a good view. Don’t expect the spectacle from the day before though.

    https://youtu.be/BszISIr4QDk

  4. Thanks Chad
    Are there full whole rock and or a comprehensive suite of ICP assays on the lava to date. Any gas sampling results? Any olivine characterization results

  5. with the earth now having two similar eruptions going, where would the next one happening to balance things out ?

    • When the eruption is over there must be a plaque placed on that spot, it was such an important place for people all over the World.
      I pray for another camera also…

      • It was the first live camera in the world knocked out by a Rifting fissure eruption lava flow!

        • No there were a few lost in Hawaii in 2018, they werent live at the time but were abandoned and the house they were in was burned down near the end of the eruption by a fire started by the lava.

          • But I believe it was the first webcam overwhelmed by lava while on ‘active duty’, i.e. transmitting images worldwide over the web. As Lughduniense indicated, clearly THE BEST!

            Of course the newly departed webcam has friends in webcam heaven, e.g. the webcams that filmed the oncoming wildfires in California over the last years. However, no other webcam can claim to have died of lava inundation, I believe…

    • I saw this in the twitterverse, claiming to be the remains of the mbl camera. just barely buried, but most definitely no longer in working condition.

  6. Thanks for the kind comments everyone 🙂

    Post is a bit more of a thought experiment than a detailed analysis, something else to consider as an outcome of this activity.

    This is also where I decided to give this eruption the name of Chadagigar, or Tjadsgigar as I have been told is the correct spelling. 🙂

  7. Great stuff.
    The Hell Machine is a great name Chad, very interesting time to have good internet connection…
    I was rather hoping for say half a degree of global cooling out of this in the next few years, go on Satan be a devil.

  8. 14 comments in 1 hour, if there is 4 days to a new post that is 96 hours, so 1344 comments, yes lets do it new record 🙂

    When this eruption or year is over there should be a look at what percentage of all comments written on Volcanocafe are about this eruption lol

  9. A good one Chad. And it touch little in to my reading aria just now. Canarias and Azores.

  10. Thank you Chad. What an interesting read! I think the Hell Machine in Iceland is having a rest….gaining som more oomph? Loved the comparisons to other odd ball eruptions .!

  11. Bravo Chad. A very enjoyable read, Lanzarote 1730..1736 has long struck me as an oddity among oceanic Island eruptions. Here we have a long lived, voluminous eruption with dozens of overlapping episodes on an old and much eroded island with no pre-existing central volcano. Lanzarote appears to have had only limited Holocene activity prior to 1730. Without a weathered old central volcano it also doesn’t seem to be an example of the rejuvenation stage of eruptions seen in some hotspot chains (e.g. Honolulu volcanics). Your idea about mantle decompression driving a self sustaining event seems worth pursuing to me … and a potentially good explanation for the current eruption.

    You also piqued my interest with the tangential reference to the long vanished komatiite.

    • Lanzarote does have an eroded central volcano but it went extinct in the Miocene, I think about 15 million years ago. Probably it does play into rejuvenation volcanism, the crust is moving much slower here, but that more seems to concern the magma type rather than the mechanism of eruption. Im curious why Oahu doesnt have eruptions like this actually, given its underlying structure is two rifting volcanoes. Kauai seems to have had voluminous rejuvenation eruptions, maybe an old comparison.

      There is also the fissure eruptions of Thjovahraun about 3600 years ago which were in the Þinvellir rift. Most eruptions in this rift are shields which seem to begin in the mantle, including the most recent one at Hallamundahraun about 1000 years ago. Thjovahraun is a fissure though, and a pretty big one at that, about as big as Holuhraun, but it lacks the massive scale flows of being a fast eruption. It looks to me like a compelling case of another hell machine.

      • Very interesting, thanks Chad. So this proposed mechanism could be in play anywhere we have had geologically recent mafic volcanism and relatively thin crust?

  12. A very short comment : Thanks a lot for this interesting post!.
    And greetings from Switzerland.

    [Welcome!! First posts are retained by out guard dog Akismet, but here you are!! / Lugh]

  13. Thank you Chad. A most interesting article.. Meanwhile it looks VVerryy cold on the peninsula this morning. It is perhaps the warmest spot around.

  14. https://www.mbl.is/frettir/innlent/2021/04/06/baedi_gossvaedin_i_beinu_streymi_a_mbl_is/
    The cam 4 or what ever it is. Now the ice is half gone it has revealed what looks like further lava progression across the desolate snow field, towards the webcam slightly, from fissure 3.
    Some of the ice on the camera is melting rather than sublimating, so that will speed up the clear view before dark I hope.

    There is an opening in the market for a live volcano cam lens heater.
    Or perhaps a drone could fly in and clean it LOL
    This time in 10 years eh!

  15. Interesting read Chad! My first experience of hot ground and crusty black lava is from a family trip to Lanzarote in 1979. We found and collected small samples of olivine in the lava, still in my box at home today. I hope to get to show my kids this ongoing eruption on Iceland soon, that would be a thrill.

  16. There have been a number of quakes under Krysuvik today, is it something to ponder on? Could there be more than one mantle crack opening on the Reykjanes peninsula, is it to far to be fed with the same dyke that is feeding Gelingadalir/Meradalir?

  17. Surtsey also was fed by magma that had collected near the crust-mantle boundary, 20 km deep, although this magma had also spend a bit of time at lower depths. It may be more similar to the current event: intermittent, long lasting, various eruption points along a short rift. It wasn’t a huge eruption overall (a but smaller than holuhraun). I would expect this eruption to do something similar, and it should stay nicely confined away from any habitation. You could perhaps have mentioned Nishinoshima although that seems to lack the rift. Mayotte is a dark horse. We don’t really know where the magma came from.

    • Surtsey was an alkaline basalt
      Much less melting than under Reykjanes

  18. Kudos Chad. Most timely and informative!
    Much appreciated for taking the time for sharing your insights (and history lesson). I have asked myself the same question as to what other global precedents we may have that’s analogous to what is going on along the Reykjanes Peninsula, and Lanzarote never crossed my mind.
    So, now that we have a glimmer of what a Hell Machine is capable of, what would/does it take to shut down an Icelandic (i.e. inland vs. underwater) closed-loop/self-sustaining system like this?
    As you explained, there is virtually unlimited heat available…more than enough to keep lava/magma from solidifying all the way to the surface, plus a magma source (mantle) to serve as main ingredients. Since the tectonically-induced quasi-extensional fracturing that was the precursor event(s) to the dike/crustal cracks to open up, (IMHO it was the earthquakes that allowed magma to being to migrate upwards, and it was not the pressure of upwards migrating magma that triggered the earthquakes) the dike/mantle magma feed is not going to close back up again due to tectonics.
    Thanks again for any additional thoughts.

    • Two obvious mechanisms could shut it down. One is to deplete the available mantle material, or the available heat, in the vicinity of the bottom of the siphon. The other is for the lava field, cones, any shield that forms, etc. to raise the overburden pressure until it is too high for further decompression melting.

  19. Thanks CHAD, interesting model with decompression melt and hot magma melting/widening and keeping dykes open. Dead end dykes would then cool and solidify whereas parts with magma flow would persist and widen as long magma is flowing. Must reach a balance somehow between heating/melting and cooling and dependent on flow rates..

  20. Finally, you have relieved my suspense, it is funny that out of all the volcanoes in Iceland, it’s this one to produce some of the richest magma we’ll likely ever see. It’s so interesting, that I might write an article on it, it wouldn’t be good as my felsic articles though. the eruption is getting more intense, albeit slowly.

  21. Thanks very much Chad (and of course Albert along with Carl and Héctor). Always looking forward to the next post.
    If this becomes a shield volcano, then we will not have Chadsgígar (Tsjadsgígar) but Tsjadsskjöldur and Tsjadsskjaldarhraun. Names to rival Eyjafjalljökul.

  22. Question : Does anybody has actuall numbers, how much Lava has erupted so far???
    Thanks….

  23. Interesting article Chad, thank you!

    I was having similar thoughts about a potential self-sustaining eruption with a positive feedback of decompression melt feeding more decompression melt, and the extreme heat of the magma at the very least preventing the conduit from narrowing.

    I do wonder what potential outcomes there are from this mechanism though; perhaps with no widening of the conduit we “just” end up with a shield (or something more short-lived), perhaps if the conduit does widen too much you end up using up the mantle-melt faster than it is generated and the eruption becomes too unstable resulting in an early termination? There must be some sort of goldilocks-zone that is optimal here because otherwise we would end up with the Siberian Traps every time decompression melt and no shallow magma chamber was involved…

    Right now I am sceptical however that the conduit has widened as, barring some brief periods of volatility before/after new vents have opened up, the output has remained remarkably static from what I’ve been able to read (despite my eyes/wishful thinking suggesting otherwise). As you say though, it’s still early days, so we shall just have to wait and see – it’s thrilling stuff!

  24. Perhaps this will form a ”Flood Shield” a term chad invented a while ago ..

    But the Morgoth vent is now dominant

    • What about east and north directions? the volcano i am looking at has recent shifts in both directions? This is actually turning into one of the most bizarre situations I have ever encountered while tracking a volcano.

  25. I see a lot of vog trailing downwind, hugging the ground and moving horizontally, from both the original eruption site and the fissure 3 cone, but none from fissure 2. Has fissure 2 shut down? 19:12 on the Meradalir RUV cam.

    • Wait — at 19:14 lava becomes visible spilling out from the fissure 2 rift to the right of the big spatter rampart. Still very little vog there though!

  26. Nice article Chad

    I’ve been noticing a lavaflow growing in the mbl cam (in the red circle), it is outside the frame of the Meradalir cam, (the green line denotes roughly the edge of the Meradalir cam, based on visible lava in both cameras at the same time). Anyways, if that lavaflow continues to grow(in the “right” direction that is), we should get a nice new river over the edge. as can be seen in the super fancy graphics below 😉 the location is most likely going to differ quite a bit from what I’ve drawn, if it even happens. But hey, one can dream 🙂

    • It looks like a fissure is opening up just north of that cone right now, between your red circle and the cone. A lot of spatter there it is…

  27. Thank you Chad for your interesting article. You were right, the eruption hasn’t slowed down, it might pick up still.

    In regard to Oahu if you go to the Halona Blowhole Lookout on the Kelaniana’Ole Highway and go over to the east side, you can find some extrusion of almost white lava in the lava tunnels, in what appears to be fairly recent activity, within the last 50 – 35,000 years as it appears that very mild volcanic activity extended the shore line out in 2 places at this location.

  28. Ignore the previous image thingy from me, seems my estimates of camera angles were wrong. Red circles here are of the same flow.

    • I was watching that as well, praying for the camera to turn right/zoom a little.

      Since the third fissure it is incredibly hard to keep track of the flows, as half of them are out of cameraview.

  29. Question: why are fisuures 1 and 3 very ‘smoke’ and fissure 2 not at all? (At least from what I have seen the last 2 hours or so)

        • I think there is. Earlier in the day you could see the smoke being blown just above the ridge, well below the cone. The ridge is build up by the lava flow itself, by the way. The smoke apparently came out low, on the other side of the ridge flow. At the moment the peak of the cone looks much more active and you can see the smoke again higher up.

          • Ahh thanks Albert! I translated ridge a bit differently, (english always been a bit difficult ). I understand what you say now. And indeed it is smoking more now.

          • There was another effect as well. From the camera point of view, the tip of the cone is against the sky, not the background hill. That makes the smoke hard to see.

  30. Just watched a few minutes ago an emergency vehicle driving down the hillside into Meradalir. I had the view zoomed in on it, and about half way down the hill it stopped and two people ran very quickly to it from the right and got in. I wonder what that was all about?

    • How much do we believe has been erupted thus far (in km3)?
      Got to be close to 0.1km3 surely?

    • Looks on the video as the flow from vent 3 (and 2) is starting to go downhill towards Meradalir but further to the south. Looked like the bikes were about to get surrounded, they left in a big hurry to the east instead of to the south.

  31. I have been mostly incommunicado for a while, except for one comment up above… So I am curious, are all the eruptions now connected by lava?

Leave a Reply