There have been some fabulous views of the volcano. And some less excellent ones. Where has it gone? Where is it going?

Who doesn’t dream of escape? Perhaps you have a mind-numbing job, a repressive social environment, or a damp and cold house. It may be an escape in (and from) a computer game, trying to reach the exit while being chased by your real-time friends becoming virtual enemies. Sometimes we need to escape from a dream, an unrealistic and damaging expectation of life. We may look forward to a better future, while forgetting that our life is the here and now. Terry Pratchett wrote about it in a children’s book, Only you can save mankind. It is about games and dreams as escapism from real life. The children have only vaguely fleshed-out personalities: they are forgotten by a world that is dealing with more important things. They come to life only in their video games, and it provides their ultimate escape.

Volcanoes too go for escape. The purpose of lava is to recreate the land: it should not be locked up inside a crater. The local people see things different, of course: it is a damaging inconvenience to have your property being claimed by lava, just for the purpose of recreation. And us, volcano watchers, are in two minds. Like Jonny in the book, we see both the game of lava and the events in the real world. It excites and frightens in equal measure.


The Geldingadalir eruption was exceptionally well placed for the purpose of isolation from the real world. The cone erupted on the side of an elevated plateau, Fagradalsfjall, in an area where a number of valleys had been eroded into the ancient lava shield. The valleys vary in depth, but have in common that they lack a direct outlet. Geldingadalir consisted (note the past tense) of two valleys with a small ridge in between. The volcano first erupted on this ridge. It was presumably a pressure ridge as it was located on – but perpendicular to – the Reykjanes fault. The lava flows remained confined to these two valleys. But they were also within walking distance of the main road. You can’t get more tourist friendly than that. In this perfect lava video game, there was to be no escape for the lava, and civilization was saved.

After a while the eruption upped its sticks and moved to higher ground next to Geldingadalir, from where it eradicated the original valleys and began to fill two others: Meradalir and Natthagi. Natthagi is a deep lying valley reaching for the coast, with an outlet only a little higher than the bottom of the valley. Escape from here seemed inevitable, but it was stopped by a combination of Icelandic engineering (the wall – from now on an essential part of any Simcity game) and volcanic temper (it stopped erupting in this direction). This saved – for now – the coastal road, a historic farm, and the newly build wall. The flows continued into Meradalir, a deep double valley separated from the lowlands beyond by a ridge. The steep ridge comes from an ancient eruption underneath the ice of the ice age – we think 35,000 years ago, based on the movement along the fault. This ridge became a useful location to put viewing cameras. The lava slowly filled up the valleys but it had a long way to go. The confinement remained.

But if the eruption continues, it is inevitable there will be an escape attempt. There are some places in Meradalir where the natural barrier is potentially overtoppable. At the moment the lava no longer seems to reach these places, because of a somewhat lower eruption rate and perhaps because of increased viscosity of the flows – they don’t look as runny as before. In the last week some of the flows have been notably sluggish. But at other times it is flowing like there is no tomorrow.

Assuming the eruption continues, where would an escape be most likely to happen? Where should we send the engineers to game a solution? Where are the danger points? And which property is ok for building a hotel?

To flow where none have flowed before

Let’s first look at the current extent of the flow. The image below is a preview of a Skysat (Planetlab) image obtained August 14, during a period of clear weather. (This probably counts as an extreme weather event in Iceland.) The image itself is high resolution (0.7 m/pixel) but is commercial and requires a hefty payment – after all, these satellites are not free to build, launch or operate. The preview shown here is of much lower resolution, but it gives a good indication of the most recent size of the lava field.

Preview Skysat image Aug 14, from Planetlab

In this image, some of the hills look dark enough to be confused with lava, because of the shadow. The sun was fairly low in the southeast when this image was taken. In Natthagi, the dark and smooth-grey is lava, and the stripy lighter grey is the shadow of the ridge on the right.

For a while lava flowed into Natthagi. The lava came close to the exit from this valley but had not quite reached it when the volcano changed direction. Over the past weeks, the eruption has left Natthagi alone and the lava has instead gone east, into Meradalir. Not all the lava went down: a fair amount remained close to the cone and build up an embankment and a shield. The embankment contains the main outflow channel. The new parasitic vent is growing on the side of this embankment. To the east of the cone the lava shield has been rapidly rising. This rise has already eradicated one hill, which first turned into an escarpment with the lava lapping against the ridge, and then was swamped by overtopping lava. The transmitter which had been mounted on this hill became the subject of a rescue attempt, not entirely successful. The rest of the lava has been flowing into Meradalir, first into the western valley and later extending into the eastern one.

The best map of the lava field is from, dated to 27 July. (The flow has thickened since but expansion has been very limited.) To the east and north of the lava flow (the ‘hraun’) is the old shield of Fagradalsfjall (which we estimate at 100,000 years old, dating from the previous interglacial). (Note that our ages come from assumptions on what lines up with what across the Reykjanes fault, and should be taken with caution and not as scientific fact.) This fjall acts as a block. Various other ridges contain the flow but these have some gaps. I have indicated the potential routes where the lava may flow through the gaps and perhaps escape. The coast lies waiting.

The current flows are down the slope into Meradalir. Natthagi is not being resupplied. The picture below is a screenshot from one of the many drone views. It shows how well developed the cone has become. The route to Natthagi would start at the back, to the south, were the cone is highest and best protected. There is no sign that a collapse here is likely. The outflow is the weak part of the cone, but any potential break here (perhaps related to the current parasite vent) will still feed towards Meradalir. A reinstatement of the Natthagi supply route can not be excluded, but it does not appear likely or imminent.

The cone and outflow. This is from before the rapid growth of the parasite vent

There have been some excellent views of the lava flows recently – as well as some very foggy days. Below is a combination of daytime view of the field on Aug 15, and a night-time view of the lava flows. The hot flows are white. Mostly it follows the northern edge of Meradalir, fed by the embanked lava river coming off the cone. This flow first runs southeast and turns northeast where it enters the slope down to Meradalir. This turn is a memory of the transmitter hill which blocked this direction before being overtopped. There is now also a flow going south and turning southeast. Finally, there has been a small flow going northwest, visible on some satellite images, but no other indications that we are missing lava.

Aug 15: day time image of the lava field, combined with a night time image of the fresh flows. Click on image for full resolution

The way out

Let’s go through the possible escape routes via Meradalir. For an overview of Meradalir, this Gutntog drone video covers it well and it is worth watching.

The north

Starting along the northern edge, lava has entered a small canyon between two ridges. The lobe is just outside of the cameras: the Meradalanuknur_SV camera is on the adjacent ridge but on the wrong side. The following image is taken from the drone video, showing this lobe – and lava flowing past it.

Drone screenshot from Gutntog, Meradalir, northern edge

Overlay of July-27 map (brown/green) with the Aug-14 image (black for lava)

contours and expansion route

The Jul 27 map shows that the lava had at this time reached the contour level at 140 meters. It has expanded further since dat date. This is evident in the overlay with the Skysat image of Aug 14: it is now approaching the 160 meters contour. The flow can expand further by about 1 kilometer if it reaches 170 meters. That is about the limit. The plateau beyond is at 200 meters: if it were to reach that height here, there would be serious outflows elsewhere. We can expect significant expansion of this lobe but not an escape.

North by northeast

A bit further east is a second lobe going north to northeast. It is running into a steep upward slope, requiring 60 meters of ascent, indicated by the arrow. This flow did not expand in the period 27 July to 14 August. The Skysat map and the July map overlap perfectly, following the 140 meter contour. However, a lava flow reached this area on Aug 15, when the flow expanded as indicated by the red hashed area. The area of the red arrow was out of sight of the camera. It may have expanded there as well. It seems plausible that the 150 meter contour had been reached here. However, the confining slope is too steep and high. This is not the way out.

Second lobe. The hashed area indicated expansion on August 15

The eastern valley – northeast

Next we come to the second valley of Meradalir. This is a fairly narrow basin running southwest to northeast. The lava has not expanded here between July 27 and Aug 14: the flows have not reached this second valley, possibly because the eruption rate reduced a bit in this phase. The current level is around the 130 meter contour. That is 45 meters above the original deepest point – in most of the valley the lava is currently some 35 meters thick, and in places more. (As an aside, at that thickness it will take a long time to cool down. Even after a month of down time, and a solid looking crust, most of the lava underneath may still be liquid. Don’t go there.)

Potential escape routes from Meradalir

This region has a number of potential escape routes which are coming into range.

Starting with the northeastern tip of the lava, there is a plateau further northeast at an elevation just over 150 meters, which is about 20 meters above the current level of the lava. This plateau is fairly wide and would give a large surface to expand into, of 500 by 500 meters, doubling the surface area of this second valley. Once it has covered this space, there is a path around the big hill to the east, where there is a shallow descent to the south. This escape route is slow, because of the wide area to be covered and because of the shallow slope.

The second valley – the routes south

There are three other escape routes from the valley, as indicated by the arrows. These are easier and more likely.

The clearest exit is in the middle of the valley. Here, the saddle in the confining ridge is less than 10 meters above the current lava surface. Crossing this saddle will bring the lava into a new valley running to the south-southeast, sloping down to the south. It is the lowest of the exits, but the saddle is narrow and this might restrict the outflow, at least for a while. However, it is the most likely path out.

The southern tip of the lava has two ways out. The lava here is at 125 meters elevation. To the southwest the saddle is 25 meters above the current lava; to the southeast the exit is some 20 meters above. These two exits have the advantage of being the shortest route to the coast and bringing a wider flow channel, but it is higher than the central way out.

Going out, may be some time

In conclusion, none of the three routes appear imminent because lava has not reached here for some time. Some outflow will happen here with a 5-10 meter rise in level, and a major outflow will occur if the level reaches 20 meters higher, to the 150 meter contour .This level has been reached in the western valley of Meradalir, but not yet in the eastern valley. If the lava flows reach this second valley again, the lava could reach this level quite quickly. The required volume is 1km by 0.5 km by 20 meters (the rough size of the eastern valley), or 0.01 km3. The eruption is producing that much in about 10 days. Of course only a fraction of the lava will reach far enough. Once it gets here again, a minor outflow may happen in a week and a major escape could occur in 2 months.

And that seems to be it: none of the available routes is likely in the near future. The nuclear option would be the flow being completely redirected away from Meradalir. However, a look at the contour maps shows that the old Geldingadalir and the valley-with-no-name (named Sydri-Meradalur on the map) are filled to between 210 and 230 meters, while the flow into Meradalir begins at 200 meters, which is considerably lower. Gravity favours Meradalir, and using the first law of physics (‘Einstein is always right’), gravity always wins. In Meradalir the flows should remain confined for the next month.

A by-pass?

Does this mean the coast is clear? Not quite. The recent re-arrangement of the volcanic cone has indicated another possibility. Over the past month the embanked lava channel has channeled the flows largely to the northern side of Meradalir. But the new vent, and holes on the side of the cone and embankment are now providing a route that runs along the southern edge of wide slope into Meradalir.

It is visible on the image at the beginning of this post. It is a shorter route into the eastern valley, although so far it hasn’t reached that. However, the region along this side where the 150 meter contour has been reached has expanded to the entrance point of the eastern valley.

A by-pass?

This opens a potential short cut. The new flow is coming down along the high hill where the contours drops from 200 meter to 150 meter. The hill ends at 180 meters. There is a passage at the 180 meter contour, in a place where the lava has already reached the 170 meters. It would not take much to enter this gap.

The arrows indicate the flow paths this could open up. It provides a shorter route into the eastern valley. It is not without problems: the gap is narrow, and may be higher or more restricted than apparent from the maps.

After the exit

An escape can therefore happen if the eruption continues as it is at the moment, perhaps by early Autumn. It brings the lava into a long, open-ended valley. It is still quite a distance from here to the coast. Progress may not be fast and the lava may get stuck if the flows are not voluminous enough, so that they solidify before getting to the exit. That would be the preferable outcome, of course, leaving both the virtual tourists and the locals happy, the former with some brilliant views, and the latter by keeping their property safe from recreation. Everyone wins in this game of life.

But if the flows heads for the coast here, it would be harder to stop it by building a wall. Simcity-Volcano has just become a lot more complicated.

Game over

Albert, August 2021

236 thoughts on “Escape

  1. In addition to the new opening in the left side of the crater rim Albert just posted about, The rim overall has shown a lot of erosion from this latest (and spectacular) eruptive episode. Several new channels in the rim are evident, whereas the rim’s crest at the beginning was much more uniform.

  2. 12:21 EDT 21 August:

    That spillway on the left appears to have remodeled some across the past 60 minutes. From the nature of the activity, that rim might just rebuild from the adding and cooling.

    • At 17:30 it looks like the flow is headed directly towards the camera!

  3. Just amazing! I feel privileged to be able to observe this.

    • Well.. sometimes reloading the page isn’t enough to see new messages I see 😀

  4. I left the Fagradal volcano one hour ago. After several hours of observations as the eruption grew in intensity. There was a break to the left in the crater rim that grew larger over time and is now letting a lot of lava escaping towards Geldingadalur . Some lava seems to creep unseen perhaps in tunnels far down the valleys towards the ses. Vapor/smoke in many places in Nathagi that showed no signs of emissions when we passed by in the morning.. sorry. No good photos and I do not know how to post.

    • The volcano is getting nearer to producing a real shield!
      Three valleys lava fed at the same time, Geldingadalir, Meradalir and Natthagi.

    • The new flow into Natthagi came unexpected. It is nice to have someone on the ground! Could the vapour be weather dependent (more humidity) or do you think the lava field is getting new heat? Is it busy around the volcano?

      • Very dry weather teatersatsning untill 1630 so I think wapor/smoke comes from new hot stuff arriving under the crust. Also, lively lava streams disappeared down under the crust high up closer to the eruption sits.

  5. Here’s a video by a visitor showing the new development:

    • Super video, panning a full 360 degrees at the end. 18.11pm, a second burst of lava has gotten 4/5ths of the way down to the valley floor. Looks like the pooled area around the saddle area got released.

    • Nina has posted another couple of videos of the stream, further down.

    • Best video I’ve seen in a while. Shows how big the mountain now is and over tops theatre hill! Most videos seems a bit obsessive about looking just at the piling in the crater. It would be nice to see a bit more of where the lava goes, or even what the crater looks like during the pause. Anyone got any recommendations for this?

  6. I’ve been enjoying watching the flows from the vent and the stills photos. Once the overspilling ceases to the southern wall, then it seems like more lava flows out of the normal eastern exit. Several few paths look to be covered over, starting overspills just upstream. One has diverted a couple of streams closer to Theatre Hill. It may have enough steam to get to Nátthagi, if the episode doesn’t shut off first.

  7. Nátthagi camera @ ~20:17:00. Lots of steam in areas from presumably rain fall near to the camera. Is the steam a consequence of past eruptions where the lava is still cooling down but still warm enough or could new freshly erupted lava already found it’s way there undetected via lava tubes and increasing temperatures close to the surface?

  8. On videos it looks like basically all the lava on the surface goes into Natthagi, theres some tube fed lava going elsewhere but how much of the total that is I dont know. But a major flow direction change seems imminent.

  9. Might be a bit hard to see but I made this, it is the approximate outline of the lava field as of now and overlayed onto Kilauea. It does really put things into perspective a bit, the volume is not trivial but perhaps we are forgetting mountains in this area are only 300 meters tall… 🙂

      • Kilaūea is insanely massive
        Most other stratocones can fit inside Kilaueas summit caldera..

        And dont forget the puna ridge its submarine slope. The whole Kilauea massive is 170 kilometers long and around 53 km wide. And still an relatively infant Hawaiian shield

        She will grow Into a massive behemoth in the future as she have just started the main shield building boost.

        Chad: How Big will Kilaūea grow? Perhaps as Big as Punahonū?

        Loihi I dont how big it will become in the future

        • Thing is I have been thinking a lot about Hector’s recent articles about Hawaiian volcanism and it makes a lot of sense. All that would mean Kilauea is not its own volcano but a satellite of Mauna Loa, which is itself a satellite of Hualalai, where the primary mantle source is. I have on my own for a while though Hualalai is a massive volcano that has been partly buried, that the Alika landslides were from it and Mauna Loa simply was more active so its rift moved to occupy that space. This is basically a variant on my idea, and going further.
          I do though have questions, because Kilauea has got multiple magma chambers, if it is a satellite itself are these magma chambers potentially their own things too, with Kilauea only properly refering to the magma body underneath the caldera and the east rift magma chambers are embryonic central volcanoes. Perhaps another 4th center will form in the area of Mauna Ulu and Pu’u O’o, when the area is deeply buried under many km of rock in the future.

          Anyway Hualalai Nui as I will call it is indeed bigger than Puhahonu, or at least the same size, it could well get a lot bigger too. Looking at Haleakala when it peaked around 2/3 of its rift was subaeiral, maybe even closer to 3/4, and this is the same of the other volcanoes further back too, all of them except Kilauea. I think ultimately about half of the Puna ridge will eventually surface to bring the total subaerial section of the rift to a length of around 90 km, which would also bring the summit to at least equal with Mauna Loa in elevation and that is before the alkalic volcanism sets in and builds it up further, like at Mauna Kea, that might get it to elevations enough to be glaciated permanently…

          • Thats really strange then..

            Needs more data to confirm his theory

          • Well many USGS data says that its Mauna Loa that sits directly on the Hotspot rather than Kilaūea and Loihi

            So yes perhaps This is correct after all

          • I am waiting for Hectors next post in the series, that is goign to explain it all better than I ever could.

            I suspect that Iceland also has this effect, where many supposed central volcanoes are in fact satallites of another. The massive volume of eruptions there will create calderas, yet in a few cases such eruptions are attributed to volcanoes with no calderas. Case in point is Heidarspodar, to me it is obviously a satellite of Krafla, all the eruptions in that area, of which there have been just 3 in the Holocene, are massive, Laxahraun (or younger Myvatnhraun) was an eruption of a comparable intensity to Laki, a 20 km curtain of fire and nearly 100 km long lava flow.

          • True satellite cones can be at any distance from the main cone. Independent cones have to be some distance apart, so that the magma chambers and conduits do not interfere. How far depends on the depth of the magma chambers. In Hawaii. the main volcanoes are a set distance apart, about 30 km, which indicates they have their own magma supply. Deeper down, of course, they do come from the same mantle melt. In Iceland the volcanoes are a bit closer to each other, and in Vatnajokul there is interaction between the magma supplies of different volcanoes at the bottom of the crust, and between separate volcanoes along the same rift. So it becomes a bit semantic what counts as ‘satellite’

        • Perhaps Kilauea is a “parasitic cone”……. 😀
          (I am not being serious, by the way.)

          • It actually could be, technically, though it is really on a scale that ‘cone’ isnt the best word I think 🙂

            Of course not all of the magma comes laterally, I think all of the volcanoes would get some amount of more direct feed, like at Kilauea Iki in 1959, that magma was from north of Kilauea not from Pahala. But in the intense heat of a plume probably the deep rifts of the volcanoes would have effects on the crust underneath, heat above and below, much weaker material.

            I do think that possibly all the magma chambers at Kilauea, where all the pit craters are, those could all count as satellitic volcanoes though. Kilauea Iki is probably a total case, it has its own deep connection and everything, just like halemaumau but less active, and it is on the ERZ but not the shallow connector.

      • Perhaps Kilaūea will reach ancient Pūhāhonus size 🙂 perhaps bigger even knowing the current sourge in Hawaii hotspots geological supply

      • chad

        While Hawaii will continue to make Islands for a very long time ..

        Whats your opinions on Icelands geological future?
        It will grow larger as long as the Hotspot as active and the ridge is spreading

        How Big will Iceland become ?


          Well, actually Iceland hotspot could have been responsible for the Siberian Traps… Than it moved over the Arctic Sea, to Newfoundland, Greenland and than to it’s present day location of Iceland. It could have been responsible for the NGLIP. I think the type of crust the hotspot is located under will also determine what kind of activity or eruptions it has.

          Yellowstone for example is moving under a deep craton. Not sure exactly what kind of implications this will have, but probably that eruptions will be even less common, and perhaps more powerful or that it will be able to crack through the craton and split, create a new ridge (like what happened during the end Triassic extinction?). The Siberian traps were also under a craton.

          Yellowstone is kind of interesting, since it’s too is tracked previously from western US to Alaska to Arctic Sea, and most likely Siberia too. The two hotspots were both supposedly in Siberia 250 million years ago?

          Also, another controversial suggestion that i haven’t been able to back up, but that i’ll just float… What if hotspots are created by massive asteroid impacts on the antipode of it’s location? like this crater for example, some people also have suggested it was responsible for the separation of Eastern Antarctica with Australia.

          • The Wilkes land crater is highly speculative. We don’t even know that it is a crater, as the signatures are not circular. At the suggested size it would be the largest one in 2 billion years. The debris should be everywhere. None has been found. That already suggests that if there is a crater it must predate Gondwana. Say a minimum of 1 billion years.

  10. Seems tremors is going up again in Iceland, let’s hope the fog does the same.

    • Sadly, the only remaining working camera is our fog-bound RUV ‘Muppet Cam’. (The one that has crowd control issues and ski-pole tossing competitions.)

      It would be good if the MBL and RUV teams could get the other cams working again. They’ll just have to send their engineers wading through rivers and pools of lava to reach them. No big deal, I’m sure, with the right overalls and boots. 🙂

      Hoping for better weather…

      • The MBL Natthagi camera does seem to be working, but everything (bar some mild steaming in the foreground) is lost in the mists.

      • Yes, it is about time the real big show of this year got its due recognition. Etna is going on at least 2x the erupted volume of Fagradalshraun in about the same timeframe.

    • Etna is incessant, wonder why there’s so much melt there and yet not so many earthquakes in that area of collision…or maybe that is the reason, it’s all mushy. Calabria is subducting extremely slowly too.

      • It is not entirely a subduction volcano, the high alkalinity of the magma shows it is from deep down. Theres a lot of places like Ambrym, Kamchatka, Masaya and New Zealand that produce tholeiitic plume basalt in an arc setting, that isnt made by hydration melting. In these places I think the volcanism is not related to subduction at all but the tectonics create a weak area for mantle decompression. True arc volcanoes tend to be dominantly andesitic from the start.

        • Good point about Ambrym and especially Masaya, probably a weak point in the crust, crust was stretched in the tyrrhenian sea

          • Come to think of it Taal probably should be in that list too, not sure of exact magma composition but it is obviously very different to the other volcanoes of Luzon.

            I did notice all the places above are rift volcanoes too,

  11. Well, lava is flowing

    That’s South Meradalir in case you were wondering 🙂

  12. When you look at the fog long enough stranger things happen ….

    • If they keep going like this, they’ll be competing with NZ for the title of the Shaky Isles.

      All in all good that the South Sandwich Islands are not exactly densely populated, so any damage will be very limited.

  13. Please post a working camera URL. None of the links I have seem to be working anymore, except a useless Nátthagi one where nothing much is happening.

    • Here is a link to all the cams. It looks like only 2 are working at the moment and a few still cameras. There is a large storm currently over south west Iceland, so it’s nearly impossible to see anything right now.

    • You are not missing much. It is pea soup weather up there. Can I point out that Grimsvotn had a yellow day and week? The first one this year, I think

      • Is this an exceptable translation of our ‘snertweer’? If so I just learned something rather useful!

        • Not identical, I am afraid. One is cold and wet, the other fog. Of course you can use any expression if it conveys the idea. Expressions evolve.

  14. It appears that something is happening…the thick fog is bright orange.

    • Long wavelengths of light penetrate fog more readily than shorter wavelengths; so the fog makes the glow of erupting lava look redder.

  15. I know it is stupid but still… Could Etna deep down be associated with iceland? Is activity so high in both places at the same time only coincidence.

    • For Etna I don’t know, but with Stromboli, it is described by Jules Verne in “Journey to the Centre of the Earth”.

  16. Not fairy tales.
    I’m looking for some serious research if there is one

    • Connected as far as they are both on Earth, otherwise no. There is a general idea that Iceland is a branch off the superplume that is under Africa, but that is on planetary scale. Etna doesnt erupt plume basalt, its magma is very similar to the magma erupting at Katla and Hekla but that is probably reflective of a similar process in the mantle than a connection, large degree of hydration melting in the mantle, so you get oxidised and alkaline magma, though melting is large.

    • It is safe to say that volcanoes more than 500 km apart are not connected at the depth where melt forms. They may still be located along the same volcanic arc, i.e. caused by the same plate collision. But Iceland and Etna are on different plate boundaries

  17. Dōshite albert-san o karakawanakereba naranai no?

  18. Pingback: Iceland’s Volcanic Theater – Dr. Roseanne Chambers

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