Kilauea I: Magma waves from the phantom rift

Each volcano is an expression of a magma architectural construction, a great sculpture of chambers, pipes and sills, as intricate as an ant colony, or rather like the roots of a plant. This is all hidden away from our view, under kilometres or tens of kilometres of rock that makes it impossible for us to know what lies down there, or perhaps not? To me a volcano is a puzzle of many aspects, geochemistry, earthquakes, structure and eruption behaviour, among others.  A puzzle can only be completed by taking all the pieces and putting them together. Not an easy task. I will attempt to assemble the puzzle, or at least part of it, of my favourite volcano. Kilauea. And it all starts with a caldera collapse in 2018.

As I write this, three years ago the summit of Kilauea volcano in Hawaii was collapsing into a caldera. Its shallow magma chamber emptied laterally through fissures in its rift. It might seem like this was a while ago and is now over, but is it? The collapse set off a series of cascading consequences that are still rippling through the molten structures of Hawaii Island. The deflations of Mauna Loa, a swarm of tremor and earthquakes under the town of Pahala, the recent eruption of Kilauea, all might be connected and it has just barely started, I will argue how this all happened and how all the events would be related.

We should first know a little about the connections of Kilauea with Mauna Loa and Pahala.


Kilauea and Mauna Loa

These two volcanoes have quite an interesting relationship. When one volcano is more active the other is less so. In particular each takes over for a period of 100-250 years, during which it gets most of the magma supply in Hawaii, then this activity goes to the other. They share the same magma supply. A far as I know this has been going non-stop for at least 2000 years. On a future article I will talk more about this aspect.

Volcanoes of Hawaii Island. From USGS.

Kilauea was dominant throughout the 18th century and until 1840. 1840-50 was a transition decade. Mauna Loa was dominant from 1850 to 1950. And Kilauea from 1960 to present. We are currently in an era of Kilauea and there is still more than forty years to go.

This relationship is best seen in the supply and the chemistry of the magmas. While Mauna Loa was dominant it erupted every ~3-4 years at an average rate of 1.2 m3/second. The total supply would also include dyke intrusions and slow spreading which could increase the total number by a factor of two or so. After the 1950 eruption its eruption frequency plummeted spectacularly. Dormancy periods have been 25, 9  and 37+ years. The output was reduced to 0.11 m3/second, a difference of a whole order of magnitude!

Kilauea mirrors Mauna Loa but in the inverse way. When Kilauea erupted continuously in the 1840-1920 period it did so at a rate of 1 m3/second and there were practically no large dyke intrusions. In contrast when Kilauea erupted continuously after 1960, during the Mauna Ulu and Pu’u’o’o eruptions, it did so at a rate of 4.1 m3/second, four times greater than in the subdued state. Ever since 1960 Kilauea has been rapidly inflating, spreading, and erupting. It has produced over 6 km3 in this time. The most productive volcano in the world. Overall Kilauea seems to erupt more, but it is clearly impacted negatively when Mauna Loa is more active.

From USGS.

Both volcanoes must feed from the same magma reservoir at depth, and through some mechanism the supply to this reservoir goes to either one or the other. But where? And how? All will be answered, but will have to wait for future articles, lets first take a look at the Pahala Swarm.


Kilauea and Pahala

A swarm of earthquakes has been raging under the town of Pahala since 2019. Actually the swarm has always been there, but its earthquake rates have skyrocketed starting in January 2019 and rising to unprecedented levels. The earthquakes are 30-40 km deep. And there is the tremor. The area just offshore Pahala is an extraordinary source of volcanic tremors. Almost all deep tremors of Hawaii originate from this location and are thought to be caused by magma rising up from the depths. Pahala would be a magma conduit then. The swarm has two parts the southern, deep, offshore swarm of of tremors, and the northern, shallower swarm of fracturing earthquakes. These two distinct parts are important when looking at the post-2018 series of events.

Deep earthquakes August-October 2019, when the Pahala Swarm was starting to ramp up. From USGS.

The Pahala Swarm is thought to be the magma feeder to Kilauea. How could we know this? When looking at a map the connection shows up quite clear, the Southwest Rift of Kilauea, which runs straight from its summit to the swarm, providing a useful connection. However the Pahala earthquakes are very deep, 30 km, does the rift really extend down to here?

Hawaii has a peculiar tectonic system powered by the magma supply. The rifts and the decollement faults. A rift is like a fracture system that is opening up and filling with magma, when simplifying things down a lot. The rift pushes away the flank of the volcano to open up space for the magma. The flank creeps on top of a nearly horizontal fault that is slightly upslope, a reverse fault, this fault is know as the basal fault, the basal detachment, or basal decollement. Why basal? Because it runs through the base of the giant lava pile that is Hawaii. Here the volcano rests on top of the depressed ocean floor 8-10 km below sea level.

The flanks of Hawaii Island are moving like a series of blocks away from certain rift zones. Crustal decollement refers to the basal fault. Created in Google Earth.

Because Kilauea is the volcano getting most of the magma now, then it is in front of Kilauea’s main rift, the East Rift, where we see these processes in action. The East Rift is continuously spreading very slowly,  pushing against the south flank which swells upward and contracts, being squeezed by the lateral pressure. This can be seen in action if one visits the data of the GPS stations that the Hawaiian Volcano Observatory is monitoring on the south flank. When the basal fault can hold no more it breaks. The fault can rupture in earthquakes reaching M 7.9, some of the most powerful volcano-tectonic earthquakes in the Planet.

With all the mightiness of the basal fault a second, more modest system is often forgotten. Which is this unfortunate fault? The Mantle Fault Zone. It is called this way because it runs at a depth of 30 kilometres, in the lithospheric mantle. It happens to be a nearly horizontal fault similar in many ways to its shallower, larger relative, it can produce earthquakes reaching up to M 5.2, but most importantly has a very particular slip direction, 137º clockwise from the north, exactly perpendicular to Kilauea’s southwest rift, and positioned is such a way that it would open up the line from Pahala to Kilauea’s summit, and at the perfect depth. To put it simple, the southwest rift extends down to the Pahala Swarm and could provide an effective pathway towards Kilauea. More evidence for a Pahala-Kilauea connection is seen in the events following 2018.

I should also say that the magma chambers of Kilauea are most of them aligned with the southwest rift. This shows when there are deep sources or deflation or inflation, one of the most common sources of deformation that shows up is an egg-shaped pattern that is centred just southwest of Kilauea’s summit, is aligned with the southwest rift, and has the long end pointing towards Pahala. The main caldera of Kilauea formed in 1500-1790, has its outer scarps rectangle shaped with its long sides running parallel to the strike of the southwest rift. Currently the main axis of the Southwest Rift runs more or less coincident with the southeast margin of Kilauea Caldera, making a nearly perfect N 47º E direction line, that is perpendicular to the Mantle Fault Zone slip, and connects the most primitive magma eruptions of Kilauea, at Kilauea Iki, and Keanakako’i Craters, and the December 1974 dyke which marks the main rifting axis of the rift zone. This is seemingly a little detached from what must have been its original position.

The “egg pattern”. From USGS.

There is yet another structure that links Pahala to the summit of Kilauea. The Kaoiki Pali. I think this pali, which means cliff, is none other than the rim of an large ancient caldera of Kilauea. Why? you may think. Because it hasn’t ruptured in over 9000 years. Fault-related scarps like those linked to the slumping or to the rifts rupture frequently over and over. Kaoiki Pali also wraps around the summit of Kilauea like other caldera faults do.

The formation of this structure happened at a very particular time. Kaoiki breaks the Pahala Ash layers that formed until 11,000 years ago, but is covered by 9000 years old flows of Mauna Loa. It formed at 11,000-9000 years. This marks the most important transition in the recent volcanism at Hawaii, where Kilauea ended a lengthy period of powerful explosive eruptions known as the Pahala Ash, and resumed summit overflowing. Mauna Loa went from a period of low activity to a period of very high activity, maybe even almost uninterrupted dominance lasting a few thousands of years. It was a big change. Kaoiki Pali could have formed if the whole complex of magma chambers and sills placed along the Southwest Rift of Kilauea collapsed. Which I think is the best, although perhaps not only, explanation.


After the 2018 eruption

Back to the big eruption. In 2018 Kilauea erupted 1.2 km3 of lava and its summit caldera underwent a nested collapse. An event on this scale had not shaken the island since at least the 1868 eruption of Mauna Loa, if not since 1790. If there was any eruption that could disturb the hellish furnaces deep under the mountains of Hawaii it would be now. What do I mean by this?

An eruption drops the pressure of a magma chamber by extracting magma from it, which may increase the resupply from the magma source to restore the pressure. It just happens that 5 months after the 2018 eruption ended the seismicity of the Pahala Swarm started ramping up towards record levels. The seismicity of the previously suspected feeder to Kilauea Volcano. So presumably it did react to Kilauea’s pressure drop.

First came the tremors. As I’ve said the Pahala Swarm has two parts, the tremor swarm at ~40 kilometres deep, and the fracturing swarm at ~35-30 km. The Pahala tremors tend to always start with a sudden jolt and then a series of later spikes, these can be located much more easily, like they were earthquakes, than other types of tremor.

The tremor came much stronger than usual in 2019. There were 4 pulses. The first pulse had its main phase in January 11-January 23. The second pulse peaked March 14-April 2. The third May 12-June 3. The last pulse came more dispersed in a series of peaks and could be considered more like a bunch of small pulses lasting from June 26 to July 27.

After the 4 big pulses the tremor activity dropped to the typical low levels until mid-2020 or so when a second series of strong tremor pulses started. I will focus only on the first series though. I do know however that there was at least one pulse in the second series, in January 2021, that does rival the 4 big pulses of 2019.

Characteristic Pahala tremor episode.

The fracturing swarm exploded into existence in August 2019. I remember being really impressed by this strong activity and yet this was nothing compared to what was to come. The rock fracturing of this type is thought to be volcano-tectonic, caused by an increase in magma pressure which shatters the rock around the magma. The Pahala Swarm started almost above the location of tremors. If the tremors were related to magma flow, then the fracturing may have been due to this same magma pulse pushing against the rocks on its way up.

The swarming initially exploded near Palima Point, and then propagated 10 km northeast, towards Kilauea, until it reached the opposite end of the Pahala Swarm, where I suppose the magma must have dived into the southwest rift of Kilauea. This happened around the time of peak earthquake activity on February 2020, when HVO was locating 80 earthquakes per day here. Unprecedented for Pahala. The levels then gradually dropped through the remainder of 2020. In 2021 earthquakes rates have started rising again and have nearly reached the levels of February 2020. The first rise August 2019-February 2020 seems to correlate with the first series of strong tremors, the second rise in 2021 seems to correlate with the second series of tremors.


Magma waves?

I was eagerly waiting the magma pulse to hit Kilauea. Perhaps a bit too impatient. It took more than a year for the pulse to move just 10 km up and 10 km sideways from the tremor area to the closest end of the swarm to Kilauea, it was obviously going to be a long wait! But finally something happened, not in the way or the place I would have expected however.

Mauna Loa got weird. Weird means that the volcano started deflating quite markedly with no apparent reason to do so. This was around October 20, 2020. Hawaiian volcanoes, and volcanoes in general, deflate when magma is removed from their magma chambers to feed intrusions or eruptions. There was certainly no eruption. I didn’t notice any intrusion either, and I think I would have noticed, or at least HVO would have. If magma wasn’t removed by the conventional ways, where did it go?

Mauna Loa deflates twice. Modified from USGS.

2nd deflation event. From USGS.

The next thing did happen where I was expecting the way I was expecting. On the morning of December 2 a sudden surge of magma hit the summit of Kilauea. It was quite dramatic. I had been following Kilauea since the 2018 eruption and not much had happened. But all of a sudden there was the fastest inflation I had seen, within a matter of hours the summit “broke”, a dike rose towards the surface but failed to erupt. Kilauea kept inflating, on December 20 it snapped again this time the dike intersected the crater of Halema’uma’u and started an eruption.

History then repeated again, Mauna Loa started deflating abruptly on March 23, 2021. Then on June 1 Kilauea set off in another episode of rapid inflation. It was time to write down the hypothesis.

Kilauea getting two magma surges. The first was responsible for the December 2020 eruption. The pause in supply that ended the eruption could be correlative with the pause in tremor activity seen in Pahala before the 2nd tremor pulse started. Modified from USGS.


Timing of events

What do we know? First, Mauna Loa and Kilauea share the same supply and must be connected at some depth somewhere. Second, a large amount of magma rose through the Pahala Swarm in a series of 4 pulses in 2019. Third, Mauna Loa and Kilauea each have been hit by two rare magma waves, producing inverse effects on them.

Here is what I think. There was a magma chamber which reacted to the 2018 eruption, this chamber is where Mauna Loa and Kilauea are connected. A series of magma pulses rose, each pulse sent two waves, a positive wave towards Pahala and then Kilauea, and a negative wave towards Mauna Loa. Why negative? With each pulse the magma chamber pressure would have dropped pressure, remember that pressure drops when it feeds an eruption or an intrusion. This is an intrusion. The pressure drops would have manifested eventually at the summit of Mauna Loa, which is apparently closer to the source because it was hit by the changes earlier. Basically it would have lost magma due to the 2018 draining of Kilauea needing urgent resupply.

Presumably each volcano has been hit by the first and second pulses of tremor that took place in 2019. There is one problem though, the distance between them seems to have changed. The first and the second came 62 days apart in the tremor region, 154 days apart as they hit Mauna Loa, and at 181 days as they hit Kilauea. This would suggest the second pulse is travelling slower than the first. It is possible that the speed at which the waves move could be slowing down. The depressurization wave created by Kilauea was the fastest to reach Pahala in 8 months, the first pulse took 23 months to travel the same route up, the second 25 months.

This makes predicting the arrival of the third pulse complicated. Assuming that the interval between the second and the third changes by the same factor as the first interval, the arrival of the wave can be estimated, though how accurate it may it be remains to be seen. It may arrive at Mauna Loa on August 17, and at Kilauea on November 20. The third could be the strongest if the number of tremors are a good indicator.



The 2018 eruption of Kilauea keeps giving new surprises 3 years later. It seems that it set off a series of waves that are rippling right now through the magma system under Hawaii, and might continue to do so for years to come. There could be a lot to learn from this. The third pulse could provide the final confirmation that Kilauea and Mauna Loa are connected through a magma chamber that feeds into Pahala, and it may also provide data regarding the properties of this connection.

Kilauea is likely to keep erupting from Halema’uma’u Crater episodically and fill up the caldera or part of it. Seeing how the pulses interact with the filling of the caldera will be most interesting.

I plan to continue this article with some others about Kilauea too. See you in the next one!.

901 thoughts on “Kilauea I: Magma waves from the phantom rift

    • I think it is on the south iceland transform fault and not on the Hekla rift but it is very close. will it do a Reykjanes?

    • Is in the area just south, where there were eruptions in 1725 and 1554, its part of the Vatnafjoll volcanic field. Probably is just tectonic but if an eruption happens here it will be a lot like Fimmvorduhals, a strombolian eruption. Magma here is alkaline direct mantle source, closer to Hekla there is much more partial melting so magma becomes less alkaline.

      An eruption at Hekla itself though will be a lot bigger, same sort of Etnean fountaining, but with it being 21 years since its last eruption it will probably be big, maybe 0.5 km3 total by now.

  1. There is a digger driving up to Natthagi, visible from 7:53 on the Geldingadalir camera

      • …and at 0735, dozer coming down, across, and over to Natthagi. 0825, tape going up along/across the trail – area where they’ll be digging for berms?

  2. Diggers working away on Natthagi exit barrier but last nights frenetic lava outflows seem to have stopped or very much reduced.

  3. In the history of Iceland, have there been any volcanic eruptions in the same period of time? If yes, which ones ?

    • I guess you mean two eruptions happening at same time in Iceland. Yes it probably has happened. And more than once as far as I remember.

      In August 1727 both Krafla and Oraefajokull were erupting at same time.

      The years before had been exciting:
      In May 1724 Krafla erupted
      In Feb 1725 Grimsvotn erupted and in April 1725 Hekla erupted. Both eruptions don’t have a known end date so they have had erupted at same time too.

      In Feb-May 1726 Bardarbunga erupted. And then In April and Dec 1728 Krafla erupted. In between these was the infamous year of 1727.

      Then in Jun-Sep 1729 Krafla erupted and Kverfjoll erupted in Feb-Mar and in Aug. So that August featured again two Icelandic eruptions at the same time.

      Moreover Bardarbunga is thought to have erupted also in 1729 so that year might have had 3 eruptions at the same region (East Iceland) at the same time, and the least in the very same year.

      • Theoretically this is quite likely to happen in 2021. Fagradalsfjall could be joined by either Grimsvotn and Hekla. Askja, Reykjanes and Krisuvik are good candidates.

      • I dont know if the first 4 years of the Myvatn fires counts as erupting, Viti formed in 1724 but the first lava was in 1727, only rifting before that. The eruption at Hekla in 1725 was also a rift too, there is the known vent south of Hekla but there was also one on its southeast flank, and another northeast in the same area as the 1878 fissure. The later ones are mostly buried since.

        1783 is another one, eruption at end if Reykjanes, out in the ocean, and then of course Laki.

        • I guess if the whole rifting event is counted as the eruption though then Hekla and Grimsvotn both erupted within the duration of the Krafla fires, for the most recent example.

  4. Theory incoming. This new barrier is to block the easy passage to the road and the ‘doomed farmhouse. Is the lava to be redirected to overflow eastwards between Slaga and Langihryggur, to cross the road and enter the sea over Skollahraun?
    Evidence: the farmhouses and summer cottages don’t seem to be empty, vehicles are there, curtains at the windows, etc etc. If this belonged to me, I’d be moving my stuff by now.
    The cable is being reinforced to the east, not in front of the Nátthagi exit. Gutn Tog’s videos leaving the area show this clearly.


      Really confused now, the contour map shows the overflow just ends up in the same area, unless the berm is going to be half-way above the rock barrier. That will be some earthwork to throw up and maintain long-term.

    • As was mentioned some time ago….is there going to be an effort to save any topsoil from the area that they figure will be overrun?

      Don’t want to strip areas that could well be spared….that would be ugly and counterproductive….but that soil is kinda priceless, no?

    • It does not seem so. The barrier would have to ba a lot higher than it currently is. It would need to be >20m to even redirect that way (behind Slaga) for a short time; unless I am reading the maps incorrectly.

      So I am not sure it can be done. The area behind Slaga is quite flat for a long time. So unless you go for making a kind of channel (artifical lava tube) or otherwise actively control the flow, there has to be quite the gradient to make lava flow stably in that direction. So the barrier would have to be even higher to redirect that way for an extended amount of time.

  5. Still minimal flow on the mbl camera, going back in time it seems to have stopped about 5 or 6 hours ago, around 04.45 camera time (i.e. time shown at bottom right of picture).

    At 7.33 camera time a guy turns up with a screwdriver to maintain the camera and solar panel, it’s 8.11 before he finishes.

    Was it Carl who said it would stop?

    • Its flowing in hidden lava tubes now thats why: and woud not be supprised that eruption rates increased. This is becomming a true pahoehoe eruption

    • Only the pulse has stopped, at 09:13 you can see the fog glow above the crater

      • There was no pulse last night that I could see, just continuous lava emission.

        I know it’s foggy, but you’d think there’d be some evidence of lava flow after about 5 am this morning. Find it hard to believe its putting out anywhere near the same volume.

        Guess we’ll find out when the fog/cloud lifts.

        PS – might have been Albert who forecast a drop or stop to emissions, based on ground deformation measurements.

  6. The Natthagi entrance cam has a new position, looking north up the path to the lava.
    It is interesting to see how heaped up the lava field looks from this point.

    It’s also an ideal position for visitors to star in their very own “Tourists Lack Talent” show.
    I look forward to it. (Not!) 🙂

    • That is the new barrier, not heaped up lava, I think. And it seems a different camera. They switched feeds

    • That should be the left (western) exit of Natthagi as shown e.g. on the following drone image:

      On the very right you can also see the distinctive green patch on the hill that was visible on the cam yesterday (right exit of the valley).

      Who would have thought that we would actually see Natthagi filled up with lave after only a few month of eruption?

      • It looked like it would take much longer than it has and it has filled up other valleys too.
        The old lava flow maps from Iceland’s (not just Iceland) previous eruptions hide many deep filled valleys, perhaps this allows us to view them differently, it certainly makes me think differently.
        If we had a time machine I think we would be quite surprised how many deep places are filled and turned into planes by relentless lava.
        That slow fissure eruption is relentless and a bit quicker than most thought it was I think.

      • It’s not full yet!

        I reckon it needs around another 1 mm3 of lava before it heads south. One days worth at current flow rates.

  7. How come this guy is in the right place at the right time?? One piece of evidence partially disproved… I’ll have to see if I can find out which summer house this is.

      Gutn Tog says in his description that this is one of the threatened summerhouses in his video that I linked above.

      Here is a screen grab from Reykjavik Grapevine’s #112 video about the doomed farmhouse. Note the fresh lorry tracks across the grass, and the double axle wheelbase (not sure that’s the correct term). And a small digger to help with the move?
      On google earth there’s a small building behind this larger extened building. I reckon that’s the summerhouse on the back of Gutn Tog’s articulated lorry.

    • Thanks for the link.
      Isn’t it typical that, with thousands of square feet to walk around in, four people walk right across his filming of the wall. Right in front of his camera. How rude can they be? Don’t these people look? It must have been painfully obvious Gutn Tog was filming.
      Rolls eyes….

    • Not sure how this is going to affect any Manxmen…
      The giggle translate is:

      “A three to five meter high defense wall will be built in the mouth of the Nátthaga valley to try to delay the lava flow from the eruption down to Suðurstrandarvegur and over Ísólfsskáli. A press release from the Civil Defense states that based on the activity in the eruption now, lava will probably reach the road in the coming weeks.

      South of Geldingadalur there is now a guide park and construction was completed yesterday. It is intended to direct lava flow from Geldingadalur from Nátthagakrik and down to Nátthaga. This is to protect important infrastructure to the west from Nátthagakrik. The guide park is about 5 meters high and 200 meters long.

      Regarding the defense wall in Nátthaga, it is expected that it will be able to delay both lava flows over Suðurstrandarvegur, so that it does not end immediately, and delay lava flows over fiber optics. “As before, the lava flow will eventually cross the park and hide its traces on its way to the sea,” says the announcement.”

      From this I gather that this newest barrier will only be a delaying tactic, to extend the time for moveable infrastructure to leave the area and immovable stuff to be protected where possible. I still like my idea of diverting the outlet eastwards over Skollahraun (the main casualty would then be the pathway up to Langihryggur).

    • They are getting less ambitious. Previously they predicted that the lava would go for to Nigeria. I guess that was the giggle translation of Natthagi, so Nigeria is now lost to Iceland’s lava

      • Probably due to Volcano Cafe patrons such as myself, who use Google translate then hit the “edit” button on the translated half to correct the translation. The giving their algorithm a little heads-up on his to improve itself

      • Just for the record ..

        I suggested this very location for the next berm project
        in a post to this thread on 06/20/2021 @ 16:47 ..
        ( see first page of comments to the OP )
        It wasn’t well recieved if you care to check the response(s) ..

        • Yes you did and asked why they did not, and got a variety of answers…

        • this is in response to Albert…. not anyone else… and yes, Triffin, in this world of uncertainty, it’s very nice to be right… long sighted You are… Gold Star! feel better now??? Hugs!

      • This should have been a new comment, not a reply to anyone in particular.

      • Mr Sigurbjörnsson does some nice stuff. i posted one of his vids of the area at the beginning of the eruption. Fagradalsfjall in the winter – hills all black with snow on top.

  8. The newly repositioned camera at Geldingadalir just switched to yet anothe angle, Natthagi from Litlahalsi. 10.06.58

  9. Friday
    25.06.2021 10:07:25 63.361 -24.166 10.0 km 3.1 99.0 23.0 km SW of Eldeyjarboði

  10. 06/23/2021 drone footage mostly of the vent but
    includes a slow 360 degree panorama view of the
    entire lava field

    • Pin sharp, too. Might that be Gutn Tog striding across the picture at 2:19? Looks like him!

  11. Another day, another batch of cam problems. The Langihryggur one has gone into blank-grey mode again, and the mbl closeup one has fallen victim to some kind of Youtube screwup. YT now refuses to display it and claims “this video is private”, even though obviously that is not correct as it’s an interionally publicly accessible webcam and has been accessible without that message for weeks.

    Does anyone have a working URL for a cam with a decent view of the vent?

    And why am I having to post here and ask that question every few days??? I don’t see any technological-feasibility reason why we can’t have a decent cam available at a fixed URL for however long the eruption lasts, instead of this constant scramble to find one that’s usable. Some problems have been with weather at the site or cameras actually getting hit by the lava, but the vast majority have been human-caused in character, from people blocking the view or hogging the bandwidth at the site to various screwups and tripped over cables at organizations like RUV, MBL, and Youtube, and this bogus “this video is private” error is yet another of these. And the frequency of the human-caused problems is not decreasing. Nobody seems to be learning from these incidents how to do better in the future. Instead, they fix whatever got broken — usually — and then just carry on exactly as before, and inevitably it happens again. This is becoming frustrating, and since I am not the one(s) who keep(s) screwing up, that is unjust.

    • It is probably exactly what you say, the providers blocking access to their streams for whatever reason. But it isnt likely malicious, they could have been required to stop the stream for any number of reasons, or even if it just got too long, like I said the last time you are taking it way too personally, its not like they stopped it on purpose to piss you off.

    • This is my go to link:
      Both of the ‘close up’ camera’s are currently unavailable and am not aware of any others except for the Langihryggur RUV camera when they periodically zoom in on the vent as part of a cycle also including Natthagi and the new berm being constructed.

    • I am afraid that VC does not control the weather in Iceland. The cameras high up on the hill will get hill fog, and the blank-greyness is exactly what there is to see at such times. At least you can know that the eruption has not gone explosive as the airborne ash would turn the view pitch black. All my views are working (I have three feeds open) but none are particularly exciting at the moment. The return of the episodic fountaining will be very nice to watch once the pea soup clears. You may expect issues with the feed – it happens to me all the time. Even VC has gone off air on rare occasions, for reasons ranging from an unpaid bill to theft of the site! As to the camera providers, do remember that every time a camera needs significant maintenance, it costs the organization ten thousand dollar. We are not paying and they are not putting adverts on. (Icelandic tourists are using the feeds to advertise a variety of bums but perhaps they are proud of them – can’t blame the companies for that.) And IMO has set the scene by making all of its instruments publicly accessible. The only regret I have is MBL forcing Virtual to take down his impressive videos, for a reason I don’t understand but what I guess involves their finance department getting upset about MBL’s investment for no clear return. My own attitude is gratitude rather than upset at teething problems.

    • I for one have had enough of reading your constant complaints. As if anyone here at VC can do anything about it.
      Being able to watch the eruption at all is a privilege. You write as though you have some kind of entitlement to see lava 24/7. In reality, we are lucky to be able to watch this at all.
      Some of us remember the days before the internet, when we thought ourselves fortunate to get a 10 second clip of an eruption on the evening news.
      You should be grateful for the fantastic views we have had of this eruption, and show support for the great organisations that allow us to see it at no expense to ourselves.
      Please consider your next post carefully. If what you have to say adds nothing to the discussion, I respectfully request that you keep it to yourself.

      • I find it truly marvellous that I can sit here in Brisbane, Australia and cast high quality video of the eruption to my TV in near real time. I have nothing but thanks for the efforts of RUV, MBL, IMO and the efforts of various enterprising Icelandic citizens.

        I doubt we’d get as good a view if a comparable eruption had occurred in any other country, except perhaps New Zealand which has a similarly pragmatic and sane attitude. Certainly if our own system in Far North Queensland were to erupt it would probably just trigger Government overreaction and OH&S nightmare with nobody allowed anywhere close.

        I really see no need for ANY complaints. Viewing this eruption is not a right, rather it is a privilege and a great pleasure… and paid for by others with no contributions from the likes of us.

  12. The eruption is episodic again, and I think it has taken out the close up live cam because it isnt showing up anywhere.

    Looks like the pulses are all directed to geldingadalir now, so could see filling there, its got quite a gradient going towards the south. Flow to north meradalur seems to be constant, in a now deeply buried tube, but flow to natthagi is episodic, sometimes it is nothing but other times it is most of the eruption going there. North meradalur will eventually reach the ocean as tube fed pahoehoe, natthagi will be a much faster flow though I think, but not long lived.

    • Fog cleared enough on the langyryggur cam to see one of the pulses, it is just like the ones through May and early June but the lava is much less channelised, though the flow is mostly into geldingadalir. There is also a powerful dome fountain, presumably the same one as before, it likely reaches 20+ meters tall, and fountaining in the main crater could be nearly 100 meters with how big the thing is now.

      • The cone hasn’t grown in height for several weeks now. I don’t think the fountains are nearly as high as they were.
        Looking at the overview camera, the standing waves during the 23.45 pm surge were spectacular.

        • hasnt grown because the fountains are not tall enough to easily reach the rim, but it is really tall now. I dont know how tal lexactly but it is easy 100+ m, my guess is even closer to 150, adding that it has also raised up the terrain around it. The cone itself is maybe 60 meters tall, but 150 meters above the ground that was there before it began.

          Something like this, I took a screenshot of the 400+ meter fountain back on May 8, so the cone then was about 70 meters tall. Now it is much bigger, might have overestimated the fountains, but they are still in the range of at least 50 meters tall, which is pretty big for lava lake activity. I would assume if there wasnt a lava lake above, that the fountains would be immense, the lava lake is going to be something like 100 meters deep in the cone by the time it overflows which is just too much to fountain through.

          • Just one sort of caveat to that last bit – if there are large enough gas bubbles, I’d still expect fountaining unless the cone rim is very high above the lava surface within it. Although now that I type that, I wonder if perhaps because the lava lake’s surface has expanded its area (ie. larger diameter/radius/circumference), bubbles are allowed to expand laterally prior to breaching the surface, thus dispersing the energy enough to avoid fountains big enough to see? That still doesn’t seem like the whole story since fluids try to take the shape of least surface tension (gas is a fluid, and that shape is a sphere). Don’t know.
            Maybe the answer is a combination of larger cone/lake and fewer large gas bubbles rising to the surface. We see splashes of methane bubbles in the ocean surface from the ocean floor (same concept – gas rising through liquid), so it doesn’t seem likely that depth is a relevant factor. I’d be happy to be educated though 😀

    • Doesn’t look that fashionable, but the plastic is perfect when you want to sit nearly anywhere without having to worry about wet ground.

      It’s also great as an improvised toboggan (bum slider) when playing on snow. Just poke two holes in the bottom corners of a plastic shopping bag, stick your legs through and off you go down the slope 🙂

      • Sarcasm was my uppermost emotion whilst creating this post. I choose to hike in clothes suitable for all conditions.
        Cardboard, tea trays, lino flooring, plastic bags; all great sledge improvisations I have seen in local parks over the years.

    • Ah – the “bumcam” at its best! Funny why they absolutely have to stand in the line of view from the webcam.

  13. I’m almost disappointed the Iceland vent has gone back to pulse mode. I enjoyed the apocalyptic outpourings yesterday night. The pulse version is a bit of a let down!
    Can someone ask the Civil Defence department to flick the volcano switch back over to full ‘on’, please?

  14. Drone video of the lava river leading to the active cone – today June 25th.

    • I wish they wouldn’t pan so quickly and abruptly, it sets my inner ear imbalance off dreadfully. 😫
      Great views nonetheless.

  15. Have the pulses of lava from the cone increased? I know that there is surging going on, but the FAF seismogram seems to show more activity then the past 2 or 3 weeks, when a pulse hits.


    Very fluid lava from Etna, only a bit more than in Iceland, and way more than is typical for a stratovolcano. Maybe Jesper is right about a lava lake being possible after all… 🙂

    The way that the lava starts gushing out of the side of the cone as the fountain peaks is concerning though, shows it might not take a lot for a flank eruption to happen.

    • That basaltic lava near the vent is still very much more Viscous than Fagradalshraun that flows like a metal flood again now.

      Etna flows at least that one haves
      No smooth paintlike crust on it.. its always broken because of higher viscosity and stress .. Etna is almost always Aa even in fast rivers

      This older Etna paroxysm while having higher eruption rates.. does seem alot more fluid

      Really really really runny lavas haves a thin plastic near vent skinn .. thats rides on it like paint and does not break up .. souch things been observered in Fagradalshraun and other Insanely runny volcanoes.. as well as sheet like overflows of glass


      Etna haves very low sillica 47%
      But temperatures are low too around 1090 C explains its higher viscosity
      But its still a quite fluid melt .. the low sillica and alkalis maybe helping Etna to stay quite fluid at lower temperatures.

      Pacaya also seems to have similar viscosity to Etna .. as well as Heimeay infact many basaltic stratovolcanoes sourely do.

      This Etna vent maybe coud be called
      ”hawaiian style” But with higher viscosity than Hawaii

      True real pahoehoe.. is quite rare on Etna

      • Etna is much more productive than any other basaltic stratovolcano though, its even outdoing most shield volcanoes. In fact individually only Kilauea significantly outperforms Etna, all the other big hitters just erupt less often, but are not too different.

        The reason for viscous flows probably is because of high fountains, lava cooling in the air. That is because of high volatility coming from rapid magma ascent, if there was shallow storage it might be different, and a lava lake would probably form. Maybe Etna did have a lava lake before 1669.

      • Etna is indeed very productive…

        But its lavas are more Viscous than Hawaii ..

        Even calm vents at the summit of Etna haves a rather Aa like structures and small scale summit activity is strombolian and can be very viscous

        But in 1998 she did some highly mobile summit lavas

        But I dont know of any true Hawaiian / Icelandic fluidity from Etna

    • Dear old Mt Etna showing off again! Myself with hearing difficulties-but appreciate hearing the raw noise-no dumn down music to ‘gentrified’ natures noise!

    • I think I get the gist with auto subtitles; magma is coming from deeper source, no signs of an imminent flank eruption, the frequent paroxysm patterns are similar in nature to the 2000 series, and the battered eastern lands cop the fallout again, although they do also get the benefit in extremely fertile soils. Did I miss anything vital?

  17. So we’re back to the old pulse pattern after a week or so of continuous outflow stopped early yesterday morning.

    Camera situation seems to be

    Ruv2 – now showing the Natthagi exit, extremely dull with no diggers and probably weeks to go before any overflow. I wish they’d go back to the Langihryggur one which showed the cone but occasionally switched to Natthagi or the Route A wall construction.

    Mbl – for some reason the close-up, probably best view feed is restricted, hope they can sort it. This page also shows Natthagi aka Bums Of Iceland (though not the height at the SW exit where the new wall is, pity) and the cone from the east side, probably the best currently available view. Lava overnight seemed to be heading south/west i.e. Natthagi via any of 3 available routes.

  18. Why did no one tell me? Katla out on Netflix since 17th June. I know what I’m doing this evening. Although it’s more of a weird one than a volcano erupting story.

    • Could a dragon please add a Trigger Alert to that video. Actually lots of trigger alerts. I meant to but I pressed submit in error and now can’t go back.

      • That is some weird stuff indeed 🙂

        I wonder if the Icelandic tourism association was happy about that production 🙂

        • My favorite volcanoes, Katla, Corbetti, Ishcia, Etna, Crater Lake, and Tatun! Let’s hope that Netflix gave one of my babies a good showing.

    • We watched it last week. We love Nordic noir – and this is definitely noir.

      Loved it.

    • ‘Katla’ on Netflix curiouser, and curiouser. Is the environment shown in the series truly that depressing or was it dressed up for the screen?

  19. Could a dragon please add a Trigger Alert to that video. Actually lots of trigger alerts. I meant to but I pressed submit in error and now can’t go back.

  20. Meradalir is filling fast. Since the last measurement on the 11th, it has filled 1/3rd of the way. Comparing to the topography map, it rose 6-7 meters in west Meradalir and about 9 m at the narrows and in east Meradalir. My calculation is that Meradalir has gained about 8 million m^3.

    12 m^3/s is about a million m^3 per day. Natthagi gained about 4 million, add Meradalir, and that leaves maybe 2-3 million m^3 unaccounted for. Some of that was an increase in Geldingadalir allowing the flow to Natthagi, and there has been a lot of accumulation around the cone in all directions (including toward the new route to Meradalir).

    • Based on the view of the Meradalir camera, the level there should be close to the overflow out of Meradalir to the east. Unfortunately that point is outside the view of that cam (to the left). You can clearly see that the Lava is still going that way, but almost entirely below the surface.

      • It is filled roughly to the 120 meter line across Meradalir. The exit should be still 15 meters or a little more higher than the current level. If it keeps up the rates of the past two weeks, it will overflow end of July/beginning of August (surface area will go up somewhat over time and west Meradalir increased less this time, but has now evened out).

        • Isn’t the lowest exit to the north? At least based on the maps i looked at.

          • No, the lowest I think is to the east, then turning south (but with only a very low grade slope southward).

            Towards Keilir, the entire area slopes upward, but only very slightly so.

  21. It seems like THE live cam (the original one, showing the first cone from the west) is gone for good, is that right? That is a bit sad, it was the only one left that allowed to see what is going on up in Geldingadalir (and hence have some advance info about whether lava will soon come down into Natthagi).

    Interestingly, it does seem like a lot of lava is going into Geldingadalir direction from the cone, but since nothing is coming out via one of the overflows into Natthagi, there must be some below-surface connection that allows for equilibration between Geldingadalir and the lake southeast of the volcano (technically south Meradalir, I think). If that is so, and if the volcano stays somewhat stable (no strong pulsin, no significant sputtering), that could mean the current flow of all new material effectively ending up in Meradalir could continue for a very long time.

    • There’s a good perched lava stream that haas been spreading its way into Geldingadalir across from the cone over the last few days. A lot of cracks and low points can swallow up a fair bit of lava. When we have had these sheets of fluid lava, they are very shallow, and possibly look to contain a lot more volume than they really do. There are also many areas of Geldingadalir to be filled, this cent seems to be very egalitarian about levelling up all the surrounding valleys.

      Yes, the original valley camera seems to be moved; such a shame as the lava switched to flow that way shortly before the change.

    • Yikes. How many meters do you think? Seems bigger than the last several.

      Where is all this magma coming from? The chamber, if it is just one chamber, must be enormous.

  22. Fagradalsfjall closing episodes, non-stop outflow again. Last 15 minutes…

  23. It was beautiful weather today after the pea soup hill fog cleared. Here are today’s satellite pictures. First in visible light showing the current extent of the lava flows

    And here with infrared colours added showing the active lava flows. As can be seen, most is in Meradalir but there is also a stream moving south which doesn’t get very far but if it continues should go to Natthagi.

    • Wow, nice! Those IR images make things VERY clear…. Is that from Sentinel?

      Does this imply that the east of meradalir is now a complete lake with a solid cool top layer that gets lifted from below, with lava showing up around the edges? Can a lake surface crust be that stable?

      But also clearly there is stuff going on in the Upper Geldingadalir. Might mean that the Natthagi escape will get a new layer on top soon.

  24. The lost tourist has been found alive and well. He had lost his sense of direction in the fog and gone northeast instead of south. He had also left his phone in the car, so had no possibility to make contact.

    • “He had lost his sense of direction in the fog and gone northeast instead of south.”

      Easy to do with no compass (remember them?), GPS or phone. Mountains in fog become unrecognisable.

      Did he find his way back or end up on the Hafnarfjordur road? Long walk.

      • If I got the translation right, he stayed put when he realised he was lost, which reduced the search area required to find him. Still, it took more than a day to do so.

  25. Etna has been making a nice long lava flow from the new hole at the base of the SE crater.
    It has been flowing for at least 6 hours after the last paroxysm.

    So, if magma rises to the top of the crater with enough pressure to force it into the air, it is also being pressed into every crack and crevice within the edifice, and thus new “mouths” can open up. (someone correct me if I’m wrong)

    Is this what causes a risk of flank eruption, that the mountain is demonstrably full of magma to the top and then some? I saw a video of the 1963 Agung eruption (with a flank collapse) and it looked like the entire interior of the mountain was hot, like a pudding, but that one is andesite.

    Note for Jesper: I can confirm now that having a typo in your email address will cause a comment to appear with the wrong “face”. It happened to me yesterday (above).

    • These mountains are demonstrably piles of junk and St. Helens spoke to that effectively.

    • I was just thinking yesterday that it was about time for an update, time to go flying again!

  26. Does anyone have a new volume estimate, and with that a flow rate estimate over the period since the last mapping flyover? I haven’t seen numbers for those here in a while.

    • It’s usually posted a couple of days after a new 3d-model is published. It’s data from the 3d-model, compared to baseline data from before the eruption, that’s used for computing the volume of erupted lava.

    • interesting how the lava skins back and folds under…. great info for anyone wanting to walk on the stuff. Thanks!

    • Those soft waves of lava moving like cake dough just make me want to poke my finger into them like when I was a kid finding tar bubbles on the road. Irresistible. It’s probably a good thing that I have very little chance of making it to Iceland.

  27. The Visir webcam is back online, but just showing fog…

    • It’s been renamed Fagradalsfjall, and it’s been moved around to view the other side of the cone!

        • great picture even in the mist, visible lava flow heading west so Natthagi destination, some fountaining.

        • I reckon it’s back-filling to the northwest corner. This looked to be lower than the rest of Geldingadalir on the latest-but-one 3D model.

        • Is there a YouTube version of this video? It would be nice to have a timeline to see earlier events. At around 22:48 today I saw some strange activity to the right of the main cone. It looked like lava bubbling and frothing just like it does in the main cone, but it didn’t last very long.

        • Amazing how it changes daily. Now lava streams on the surface, looking to just pass west of former Theatre Hill.

          “back-filling to the northwest corner”

          Could be, pretty much everywhere in the valleys is lower than that massive lava shield between the cone and Theatre Hill.

    • Must be some sort of record this year, the amount of eruptions. 43 this year and there were a few at the end of last year too, it must be getting near 50 since the current episode began. I cant see how this wont end with a flank eruption, an eccentric eruption that could be at low altitude. The power of this years eruptions too is extraordinary, especially the 2 km tall lava fountains a few months ago. The SEC complex is huge now, it is hundreds of meters tall and would be a full stratovolcano in its own right if not at the top of Etna, and most of it is formed in the last 10 years.

      The high fluidity of the recent lava is concerning, shows it is hot and fresh, a major flank eruption of that stuff is going to do a lot of damage.

      • I’m a bit hazy about it, but I seem to recall geophysicists / volcanologists saying that the magma and eruption style for Etna was undergoing change. I read about it back in the 1990s (desperately racks aged brains for information…memories…anything other than a deep dark hole). It was about the magma source changing from the movement of the Africa and that platey bit with Sicily on it.
        (I need another coffee….. Sorry 🙁 )

        It would seem this is happening now. Curious to see how the continues.

        • Every time I look at that Webcam of Etna the cone is in a different place. I assume it’s the camera view changing, and not the cone wandering around!
          That’s a heck of a big cone evolving there. A bit worrying, really.

          • I presume that the different layers of spatter that make up the cone are among its potential issues, some layers will be weaker or more likely to be slippery when weight is added, like the cones in the current Icelandic eruption.
            I loved the way the cone fragments wandered down the valley earlier on in Iceland.
            Etna would not see such slow movement I guess.
            Boris said in an interview a while back, “In the past 1000(I think he said 1 or 2 thousand) years only 71 people have died because of Etna eruptions.”
            I guess most of the death toll would be pyroclastic flank related.
            Still not a bad high total for such a dangerous looking beast eh?

          • Actually most or all the deaths are people standing near lava when it flows into water of some sort, steam explosions and such.

  28. I need the help of a meteorologist.
    What is the deal with southern Reykjanes?
    In Iceland we have recently had the best days of summer. Clear skies and beautiful weather in the south and a heatwave in the east and north. But Geldingadalir, FOG!

    • Iceland is mostly affected by a sourhwest flow in summer, which brings cloudy or rainy weather to the southwest and wear but warm and dry weather in the rain shadows which is the east and north of Iceland.

      Thw rain shadow phenomena means good weather can also occur in some spots across the south of Iceland, but at Reykjanes even in dry weather, fog tends to form. As it is a peninsula surrounded by water.

      • and here a near by town always has fog when Cook Inlet bakes in beautiful sunny weather and sends the fog northward. The rest of us have beautiful weather… no one wants to tell them shhhh.

    • In addition to everything mentioned, enclosed valleys also trap moistrue and will take longer to clear. You also have the gas production and probably small bits of dust/rock etc, which enables droplets to form. Add to that the effect of telephoto lenses compressing any impurities in the air and visibiliey will seem even worse.

  29. Given all the excitement happening at Etna this year, maybe the dragons can send out an invite to Boris Behncke if he’d be willing to write a guest post about Etna? In years past he was active on a variety of volcano blogs and willing to share his insights. Maybe he’d be willing to make a guest appearance here?

  30. This Sentinel dataset from 26/6/2021 clearly shows recently erupted lava in Geldingadalir slowly making its way south, as well as still hot lava in northern Meradalir

    • Thanks for the link to that site! I did not know that portal, it is pretty amazing…

      • It is scary yes, a lava flood so close to Reykjavik. Even if the city itself is likely safe it is a scary situation. If a fissure opens further along the rift than Burfell though it could be a real threat, I think the terrain could be higher that direction so an eruption will break out of the dike further south but you never really know.

  31. There were news of an American tourist that almost died at the eruption site by getting lost. He did several mistakes despite being a somewhat experienced hiker:
    He didn’t carry a mobile phone
    He didn’t carry water
    He separated from his partner and they followed different paths.

    All stupid mistakes that can cost your life.
    If you want to hike in Iceland do also this:

    1. Take waterproofs and warm clothing and boots (for cold chilly conditions) even if the weather is warm and dry (you never know it!). If you don’t have these, stick to stay where the crowds are
    2. Always but always take water and food with you. Food boosts energy and morale and low blood sugar is a life threat. Dehydration also kills you within days.
    3. Always take a charged mobile phone and be aware that network might be not possible. Therefore carry also a map and compass (it’s cheap so no excuse not to have one). At least have these in your phone. You might be alone, break a leg and be in a site without mobile connectivity. What do you do then?
    4. Tell someone where you are heading, exactly. So if you “disappear”, someone else will call a rescue to you.
    5. Carry an emergency blanket and ideally know how to make a fire in the wild or have a flare, so if you get lost you can show yourself to the search teams
    6. Be mindful of what you can do and you cannot do and know your limits (if you never hiked that much before, Iceland shouldn’t be your next step up because of a multitude of risks and difficult terrain and weather). Do not walk in dangerous sites like steep or slippery slopes as risk of fall is significant in those sites (avoid rainy weather and windy weather for big ascents). Did I mention to avoid narrow ridges with falls in both sides, yes, avoid those especially in windy or rainy weather!
    7. Winter hiking is a whole new level of risk, so I am not even to talk about crampons, ice axe, avalanch reading or avoiding crevisses and snow bridges. Summer hiking is far safer than winter hiking. Most deaths to hikers occur in winter.
    8. Be very careful fording rivers. Don’t do it if you feel water is too deep.
    9. Stay well away from erupting vents, lava flows, (and also from glacial flood terrain). Walking over fresh lava is out of the question!
    10. Do not walk over geothermal fields and springs. Ground can break and you can burn yourself very seriously. It happens to people in Iceland.

    Be mindful of these 10 points and if you are not a fool, you will be able to enjoy your hiking in an adventurous and safe way.

    • all good points…. and one more… “silty” water has a greater force than clear. Hypothermia can happen any day.

    • Even in england, let alone much of the USA and iceland looks very hazardous to me and I have done quite a bit of hiking. Always have a map and compass (in fact all rucksacks in this house have a small combined whistle, compass and thermometer tied to them, you never know). Cheap as chips eg eBay item number:
      373408924229.Avoid fording streams unless the weather is hot and dry (ie tropics/desert areas, bilharzia check) because they are always 10x harder than they look if its stony. If you do not have a map even well marked trails can kill. Most places outside the UK provide local maps at the park entrance, use them or better buy a local map (if staying in one area). Iceland looks to be a lot like the UK moors, all the hills are similar shapes, similar colours and there are no landmarks so without true gps its easy to get into trouble. The only saving grace is they do not seem to have the large expanses of peat bogland found in the UK moors.

    • “Ground can break and you can burn yourself”

      I remember at Reykjadalur a small hole in the path with boiling water beneath – on the way back it had increased in size perceptibly. Reported it to the tourist lady in Hveragerdi, when we returned a year or two later it had eaten the whole path which now featured a bridge over a boiling pond!

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