Did you notice the erupting Supervolcano?

Carl

This idyllic scene is from Lake Tondano situated within the 20 by 30km Tondano Caldera

This post was written by Carl in 2012, during an eruption of Soputan. Some updates have been done and some hindsight has been added.

Some volcanoes just can’t catch a break. Imagine for a little while that you are a bona fidé supervolcano. You are the largest of your type on the planet, you are highly active, and by gosh you have shown what you are capable of. In a perfect world your 20 by 30 kilometer caldera explosion should have put the world into awe, and the 1,000 cubic kilometer of DRE you ejected in the form of pumicious tuff covers an entire sub-continent. Yepp, you really did reach the small highly exclusive club of VEI-8 volcanoes. You smirk at your little siblings with their VEI 6 and 7’s – just to show the you did a VEI 7 yourself as well, as an afterthought. To top it off you have a huge underground reservoir of liquid acid that would seriously alter the planets weather if you felt like discharging it. You are also perfectly located to have a maximum kill ratio. So, you wake up and stretch your arms and start a double eruption from two different sub-volcanoes just to celebrate the new day. You have your largest eruption in recorded history. Then you look around to see the fearful faces of the residents as they offer up motorcycles in your name, you expect volcanologists doing somersaults as they play lip banjo, and literally thousands of blog pages glorifying your power and shear awesomeness. What do you find? Yawning people and a cockerel trying to wake up a pig sty. You find that for being an erupting supervolcano you are a massive PR failure. One single small earthquake at Yellowstone outperforms you in publicity.

Tondano

The quarternary volcano of Tondano in northern Sulawesi (Indonesia) had a massive caldera event. Later, a newly formed volcano blew up in a VEI-7 or so event and formed the Pangalombian caldera, 5 by 3.5 km across. Parts of the Pangalombian caldera were later covered by the now dormant Tompaso volcano that ejected large amounts of basaltic andesites in a long series of VEI-6 eruptions.

The caldera formed within a pull-apart basin, aided by a slip-strike fault to the west, through the two mentioned caldera-forming eruptions. They left their deposits, up to 200-meter thick white rhyodacitic ignimbrite and tuff which extend as far as 50 km north of the caldera, and grey dacitic tuffs found mainly to the north and west. The large eruption which produced the Tondano tuff has been dated to 900,000 years ago although older dates have also been suggested. The dacitic eruption that was produced by the smaller Pangalombian eruption happened some time before 500,000 years ago. Outside of the major eruptions the region produced andesite and basaltic andesite. Lava that predates the caldera formation includes hyaloclastites, indicating was at or below sea level.

The main volcanic activity is now on the western side where the Soputan volcanic complex is. The development seems not well studied. The region has many smilarities to Toba, which also formed in a pull-away basin, but because it is older it is not as well preserved or obvious.

Today’s Tondano is known for having acidic maar eruptions inside the caldera, a couple of mud volcano events during recorded history and no less than 4 active volcanoes, Lokon-Empung, Mahawu, Sempu and Soputan. Quite often Lokon-Empung and Soputan have tandem eruptions.

Lokon-Empung

Lokon-Empung is a double coned strato-volcano located at the northern rim of Tondano. The two peaks of Lokon and Empung are 2 kilometers apart. Lokon is a flat topped probably dormant volcano that no longer exhibits a crater on top and Empung is a historically active volcano that last erupted 1775. From 1829 onwards, Tompaluan, a smaller double crater situated in the saddle pass between Empung and Lokon, has been the site of no less than 25 eruptions. It erupted in 2011 in an eruption that lasted until September 2013, in 2012 briefly in tandem with Soputan. The eruption ended in 2015 and this highly active volcano has not erupted since.

The 2011-2013 eruption was a VEI-2 eruption, with multiple small explosive ash eruptions.

Soputan

This small stratovolcano is located on the southern rim of the Tondano caldera. It is part of trending line of ring dyke vents that formed in consecutive eruptions ending with the formation of Soputan stratovolcano. It normally erupts from either the flanking vent of Aeseput ((which formed in 1906) or through the unusually large summit crater that pretty much has the same width as the top of the stratovolcano. This is of course a sign of a very young volcano with a potent vent system.

Explosive eruptions have become frequent at Soputan with 12 episodes since 2000, the last one in April 2020. A lava dome began to grow in 1991 and began to collapse in 2005.

The more recent of these eruptions resulted in destruction of an active summit lava dome that had been growing since 1991. On three occasions did eruption lead to ash clouds more than 10 km high. Soputan is an unusual example of an explosive basaltic volcano.

The 2012 eruption lasted from 26 Augustus to 19 September and reached VEI 3, as is common for Soputan, with small to moderate explosive ash plumes. The ash columns according to the Darwin VAAC were up towards 12.1km, with several slightly smaller columns reaching 9km height.

The system

As any volcano capable of a large caldera event Tondano has a large and intricate internal plumbing. It is believed that there is a very large reformed magma chamber at depth. As pressure increases in that magma chamber when new hot magma arrives it is believed that the magma either goes up into the caldera as emplacements, and that those sometimes cause maar explosions or reheats the very active thermal fields contained within the caldera. Or that the magma is pushed up into smaller sub-chambers under the active rim volcanoes. When that happens eruptions normally follow very rapidly. The rim volcanoes appear systemically interconnected somehow. During 2012, Soputan erupted after Lokon-Empung ceased, and when the latter volcano resumed Soputan stopped 4 days later while Lokon-Empung continued for just over a year. In 2020, volcanic earthquakes led to warnings being raised for Lokon-Empung, but instead Soputan erupted. It seems that one volcano can release the pressure on the other.

As any Somma volcano the Tondano caldera is highly intricate and complex, and still it is surprisingly badly researched. The only good material is an Icelandic funded study on the possibility for hydrothermal energy plants in the region. Yepp, the Icelanders are going international with their know-how.

Why it won’t happen

Image by Andreas / AFP – Getty Images. This image shows how relatively close the volcano is to villages, the height of the ash column and at the same time that the base of the ash column is equally wide to the width of the top of the volcano of Soputan.

For those who dream dark dreams about enormously destructive eruptions Tondano is a bad bet. Why? Tondano has it all really, large magmatic influx, steady inflation, a large central chamber, active volcanism. Pretty much everything that it should need for a VEI-8 eruption. Except for 3 small things.

It does not any longer have the amount of water necessary to drive an eruption like that. As many of you know water is a large part of large caldera events. When Tondano went massively caldera it was situated pretty much at ocean level, so as the final large eruption (probably a large VEI-7) happened and the top of the caldera slumped inwards the ocean roared in and what is probably the largest steam explosion happened. Think of it as hundreds of Krakatau eruptions happening at the same time, and you have the picture. As time has passed the land has been lifted due to tectonic uplift.

Second thing is that the magma before the massive caldera event was highly crystallized rhyolites. After the eruption the magmas have been predominantly alkali basalt-andesites.

And the third reason is that Tondano is very well vented as long as the rim volcanoes are connected to the central magma chamber. As soon as the pressure gets above a certain level the magma squirts into the sub-chambers and the volcano on top erupts.

To put it simply, Tondano is a champagne bottle with 5 bottlenecks. The cork is well fastened on top of the actual central chamber, so it cannot erupt that way. Then it has one volcano with the cork slammed back fairly well (Sempu), but that is not fully dormant, one that has the cork put lightly back on (Mahawu) and two bottlenecks that haven’t seen a cork for hundreds of years.

Basically, the pressure is almost constantly being released by Lokon-Empung and Soputan, and when that is not enough Mahawu erupts too. The last time Mahawu erupted with another of the volcanoes it coincided with Lokon-Empung in 1958. Currently even if the pressure got really high the only thing that would happen is that all 4 volcanoes would go off in minor eruptions

The only risk for anything really interesting happening would be if one or two of the vents got blocked off. Even then no caldera event would happen, but the likelihood of a Vesuvius like event would increase. Currently the candidate for that is either Lokon-Empung or Soputan. Soputan seems to have a very wide bore caliber vent so it could probably release the pressure without exploding from the face of the planet. But Lokon-Empung has evolved quite a lot more, and as it has grown older the vent has narrowed down considerably. If Lokon-Empung was subjected to high pressure it would probably not be able to handle the stress and subsequently could go off with up to a VEI-6. This is though not likely at current geological timescale.

The only real risk is that a magmatic emplacement will happen in, or around the large reservoir of sulphuric acid (water with a ph of 2). I think anybody can imagine how un-nice a maar event, or even worse, a phreatic explosion, would be if it happened to cubic kilometers of liquid acid. Not a nice thought , an acid caldera event. I would decidedly not want to be around if that happens.

Tondano today

A 2013 eruption of Lokon-Empung

For being a highly active volcanic region with at best medium risk of fatalities the volcano is surprisingly badly monitored and highly under-studied. Almost all I have written is from one study alone, and that was produced by Orkustöfnun as a part of the geothermal engineering program.

In reality if we look beyond the doom and gloom prophecies of a large caldera event volcano the risk is the bad monitoring. The area is heavily populated and an unexpected VEI-4 eruption at a flanking vent, or lahars, or pyroclastic flows will kill people, potentially quite a few people.

A thought

When a volcano of this size erupts and the world’s volcanologists, volcano-bloggers, and generally the large number of volcano aficionados yawn and continue to look at other less interesting volcanoes that are not even erupting, then something is a bit wrong. I happily admit that it took me almost a week before I actually got around researching the volcano. Then my jaw dropped and I started doing somersaults while playing lip banjo. It is just the sad truth that there are more well known supervolcanoes in the western world that steal all the attention.

While we sit and moan about there being no interesting eruption we did not even reflect as we read that two more volcanoes in Indonesia erupted simultaneously 30km from each other. The only comments about it was that people rode their motorcycles inside an ash cloud to get to and from work (Lokon-Empung), and that a rooster cackled at a video of Soputan barfing up a 9km ash column. Then we went back to looking at out Katlas, Heklas, and the rest of the non-erupting volcanoes. Indonesian volcanoes could do with a good PR-agency.

CARL

http://www.os.is/gogn/unu-gtp-report/UNU-GTP-2010-03.pdf

81 thoughts on “Did you notice the erupting Supervolcano?

  1. In terms of being alerted to danger, I am reminded of a night about 20 years ago when I was woken at about 4:00 AM by an alcoholic girlfriend gently sliding the serrated edge of a steak knife across my throat. I lay still and she quietly slid the knife back under her pillow and went back to sleep, as did I.

    Knowing what she was capable of, the next day I made arrangements to send the woman and her pet cat back to her homeland, putting 15,863 kilometers between us. I’m not sure where the local residents around the Tondono Caldera should be going, but I am quite certain it involves a considerable distance.

      • Nah. She was an American I contracted for a software project. She wanted to bring a 45 Magnum to Australia for protection; but we have gun laws that preclude that. The steak knife was an easily available security alternative. She’d had a tough life with cause to be wary of men. The possibility of cutting my throat was not the first outside the box thought she’d entertained and not actioned. Her idiosyncrasies made her a clever and entertaining thinker. I was more bemused than afraid. It would have required violence on my part and fear on hers for that knife to draw blood. There was a bond of mutual affection that engendered trust; but the potential for a psychotic episode was obvious; and I am generously endowed with flaws that can trip anyone’s sanity hair trigger.

        Back to psychotic volcanoes and how to avoid them.

        • .45 Mag… good stopping power.

          The cartridge did not gain much popularity due to the intermittent availability of the Wildey and LAR Grizzly pistols.

          Trivia note: The US Military adopted it as a side arm since the .45 had a greater stopping power over the .38 during the Moro Rebellion. The higher kinetic energy virtually ensure that your target is gonna drop. But to go with a magnum version? Jeabous. She means business.

          Note: Modern 9mm weapons have come into common usage as side arms due to comparable energy and increased magazine capacity. Personally, I still prefer the .45 ACP though it is not as nasty as the magnum load. Though fairly proficient with a 1911A, I could barely qualify with a “service six” .38, even going as far as putting a round in the wrong target on a K course. The weapon has that much slop in its construction.

          • I was told Alabama menfolk are 23.6% harder to stop because they are raised on shrimp and grits.

          • The Sahara used to be much wetter. Even 3000 years ago it was more habitable than it is now. It is related to the earth orbital changes. We are now pretty much at peak dryness. Over the next several thousand years it may start to recover and by 10,000 years from now it should again be green.

  2. Indonesia seems to have quiet a few volcanoes which have been changing history, is it because it mostly is near the equator and the rotation of the earth is collecting all the stuff for a release a.k. eruption ?

    • Not really. Indonesia lies along the plate boundary between the Indo-Australian plate and several smaller plates, e.g. the Sunda Plate. The Indo-Australian plate subjects under the other plates; dehydration melting caused by the subduction generates the magma for the volcanoes.

  3. “Super volcanoes” erupt relatively frequently. One issue I would contend is the lack of water, Volcanoes well inland and away from abundant sources of water have produced huge explosive eruptions.

    • Not sure you need water for a caldera forming event, either. Many caldera’s are formed when the roof of the magma chamber / reservoir sinks after the magma that supported it has evacuated.

    • Altiplano-Puna case in point, think it just requires a firm lid (ice cap or thick crust) and a large upwelling or melt. Of course these might have large hydrothermal systems.

    • Aira Is a Scary volcano, with monsterious capabilities if its not well vented. A 600 km3 pyroclastic event today woud kill tens of millions.

      But its well vented with Sakurajima and perhaps haves no large sillic resovair avaible for now? Aira is probaly deeply feed by evolving basalt / basaltic andesite

      • Not sure that Sakurajima does enough to be reassuring, some evidence that the caldera is inflating despite Sakurajima’s efforts – which have in fact erupted very little magma since the last major episode (1914?). Recent activity has been pretty well the volcanic equivalent of a wet fart with no effect on the main magma body. Not too different from Aso in that regard

      • Jesper,

        Sakurajima has been able to vent some, but the larger Aira magma chamber is still inflating. So in other words, while there is some venting, it’s not offsetting re-accumulation of magma in the bigger Aira system.

        I truly believe that southern japan has a lot of similarities to a young and developing Taupo Volcanic Zone.

        I wrote this a while back, and it’s still a good read on the region:

        https://volcanocafe.wordpress.com/2013/07/22/southern-japan-calderas/

        • The region is collecting more magma than is being erupted. We briefly discussed it in our Up post https://www.volcanocafe.org/up/ If the 130-year gap between major eruptions hold, than the next significant eruption may happen in the 2040’s.

        • Nice to see the return of some of the older articles. When the website changed it made it much harder to find the oldies.

          • If you have any requests, let us know. The ‘oldies’ do sometimes need updating.

          • Been interested in Hokkaido of late. Anything there would be good. Also the Philippines (Mindanao specifically).

            I’m sure others have other interests.

  4. Good evening, excuse me for the out of theme, but a russian scientist, Lobanovsky, revisited the estimated energy from the Krakatoa eruption in 1883, togheter with the energy of other phenomena (Chelyabinsk meteor, Tunguska, etc…). It’s very interesting. Taking in consideration different factors, for example historical documents, infrasound waves, the distamce of the windows broken, etc… the energy of the Krakatoa eruption is approximately 1 GT, a very different estimate than the official one, 200 MT, which is, for him, very little.
    I think that the reference is to the explosion of the 10:02 of 27th August, the greatest, not to the entire eruption.
    Personally, for me this research is very good, the only doubt is this: how is it possible that an explosion of 1 GT didn’t destroy, besides almost the entire Krakatoa, Lang and Verlateng too?
    Furthermore, I don’t think that Tambora eruption was more powerful than that Krakatoa.

    https://arxiv.org/ftp/arxiv/papers/1311/1311.6565.pdf

    • In facts, simulating a surface (not airbust) 100 MT explosion with Nukemaps: https://nuclearsecrecy.com/nukemap/
      can be seen that the shockwaves breaking the windows reach the coastline of the Sunda Strait, but they are far to reach Batavia (Jakarta), at the distance of approximately 150 km. But windows in Batavia was broked.
      Another doubt is the presence, at the time, of vessels, like Norham Castle that reported the shatterd ear-drums of half of its crew; how is it possible that, however, they survived to a approximately 1 GT explosion? Nautil.us http://nautil.us/issue/38/noise/the-sound-so-loud-that-it-circled-the-earth-four-times reportes that Norham Castle was 40 (nautical) miles from Krakatoa; they are 74 km. I wonder if the shockwave of such an explosion at that distance is so weak that it only destroys the eardrums.

    • The explosion may not have destroyed the island of Krakatau; it is believed that sank as the magma chamber emptied.

      The large blasts on 27 August 1883 may have been caused by seawater getting into the magma chamber and/or sudden magma mixing.

      All the vegetation on Lang and Verlateng was destroyed and the islands changed shape – ultimately enlarged by tephra fall. Polish Hat disappeared.

      No idea why Lang and Verlateng were not destroyed, other than the land did not sink under them. Perhaps the blast was not big enough, there were gaps between islands for the blast waves to pass through, or the blasts were directional?

      Would a boat survive because it was on water and facing in the right direction? So it could move with the blast wave rather than be knocked over?

    • This is a poor paper. Not even a student paper could get away with quoting Wikipedia and Discovery channel as their primary evidence. They ignore the refraction of sound waves closer to the eruption. That does not affect high altitude bursts, but it is vey important for explosions at sea level. Within tens of kilometer, the sound bends away from the surface and you don’t hear anything. People that far from St Helens never heard the explosion. You can see a distant thunderstorm on the horizon, but you can’t hear it. Further away the sound reflects of the stratosphere and is focussed to the ground. So you hear bangs again, often compared to cannon fire. Mining explosions are sometimes heard in one location several hundred kilometers away. The acoustic energy is obviously uncertain. But this does not solve it.

        • That the only place in the Taupo Volcanic Zone that is currently showing inflation is on the coastline and that it is also underneath the town (city?) of Whakatane…?

          If it isnt that then dibs…. 🙂

  5. Sangay did a good sized eruption FL400 yesterday.

    Video is a compilation of sources with good footage from Martin Reitze included.

    • An eruption to 40,000 feet is pretty impressive; even allowing for the fact of the crater being at an elevation of around 15.000 feet. One day Sangay will collapse into the Amazon lowlands, it’s done so at least twice already

      • How tall did it get before it collapsed before? 5000M is a tall stratovolcano, especially if relatively isolated.

        • The 5000m figure is its height asl. The ‘prominence’ of the cone (height above its base) is around 1700m or c.5000 feet, so not oversized, BUT on the eastern slope of the Andes, so not, as it were, on a level playing field

  6. The Grimsvötn CSM is again trending upwards, will this perhabs be the last vertical push for it? Could or could not be…

    • Kilauea is trending upwards too, now quite noticeably. Will the two erupt together in tandem? Has been a while since we got to see any flowing lava so to have these two ramping to eruption at the same time is exiting 🙂

      • I don’t see much evidence for a notable uptick. There is no clear pattern. The DI events have stopped, that is notable.

        • Its in the GPS, they are all going up now, and actually up as in vertical not cross caldera distance (which is also increasing). The quake count along the upper east rift and summit is also much higher, 10+ a day on the quake map and constant tremors. The DI events historically are actually correlated strongly with eruptive activity, and new breakouts or rift eruptions occurred during the Pu’u O’o era when DI events stopped and continuous upward trend on the tiltmeter was observed.

          Im not sure exactly what HVO are actually expecting to see to increase the alert level because Kilauea is clearly the more active of the two as of recent weeks but still on green alert while Mauna Loa is yellow from doing basically nothing. Im not confident there will be as much warning as they expect, there have been prior eruptions preceded by mere hours, 1967 was something like 15 minutes and that was after 2 years since the previous eruption.

          🙂

          • And the 1952 eruption was preceded by just about 1-2 minutes of tremor, so basically nothing.

            DI events could have a lot of value on forecasting behaviour of the volcano but only if they were well understood, or even a little understood, because currently we really know nothing about what causes them. They do not always stop before eruptions, the Kamoamoa fissure eruption 2011 was for example preceded by large deep DI events, as far as I know there is no correlation.

            I do not see anything to indicate an upcoming eruption right not, but an eruption could happen any time really, or could still be far off.

          • Seismometer grid wasnt very sensitive in 1952, it was upgraded in the 50s upon recognition of increasing activity at Kilauea, particularly after 1955. Still 1952 was very abrupt, and you are right about actual felt seismicity being only a few minutes.

            DI events are I believe associated with gas pistoningn the lake could be dissolving a lot of SO2 and masking that there could be magma shallower than 1 km below the lake, there are also those two persistent hot fumaroles on the wall. The recent DI gap also begun after a swarm of tiny quakes along the summit and upper east rift, the same areas showing much activity now, and GPS showing inflation since then too. Agreed that an eruption is not immediate but almost certainly before June next year. That is also the sort of calculated range of the next Grimsvotn eruption, still a possibility 🙂

          • I think 2011 was not typical, before that you had a massive lava lake and at least 4 vents in the Pu’u O’o area degassing the magma, that eruption was a simple gravitational drain and erupted directly out of the Pu’u O’o feeder, the eruption rate was high but fountaining was relatively low so the magma was probably degassed somewhat most likely by the summit vent. 2007 saw a superficially similar event and a tiny eruption, but this was a direct eruption from the summit not from the Pu’u O’o system. It was also before the lava lake appeared too so the 2007 fathers day intrusion and eruption never went near the surface before, it saw no DI events prior.

            I dont know about other eruptions before 2007 but I suspect DI events are linked to stability, when they stop usually means something is going to happen.

          • Of course now that I decide to point this out the quakes stop and tilt flattens out 🙁

          • 2011 and 2007 are similar to each other, they are among the largest intrusions of the Pu’u’o’o eruption, there are nice dyke models of the 2. 2007 was a doble event, one dyke fed from the Aloi chamber and the other from Alae. 2011 was one dyke that fed from both Napau and Makaopuhi. Both were ERZ events, that means the magma comes from the ERZ itself, the summit only plays the role in resupplying.

            I do not see any unusual stop in DI events before any of the two eruptions. There werent many DI events before 2007 but neither were there in previous years, overall DI events were unfrequent back then. Their number has generally been going up during the past decades.

  7. There was life here once, but now there is nothing. Nothing but a cold silence and remnants of a once bustling blog. Am I alone? I don’t know. Is there anything for me left? I don’t care. All I can do is wander this silent comment section hoping for just a glimmer of life. A cruel fate but something I’ve grown accustomed to, something I’ve lived with ever since I was a baby. This is my life

      • Who shall impede my progress? One must rise up from here to combat my efforts to awaken every caldera on this good Earth, and have them rain death upon these wretched humans. If one refuses then the sunlight will fade into eternal darkness, it’s heat gone, making way for a terrible cold. I shall succeed and the only hope you all have is to stop me.
        That is if you can.

        • You’d have more luck raining death upon humanity if you didn’t rely on geology to achieve it Talis. The show starts soon.

          Edited – rather severely. You were attacking all sides equally but it could still be seen as against our first rule. And the bar (socially distanced) is better suited for discussions on this topic – admin

      • All the Icelandic volcanoes are currently moving along SLOWLY. Same thing with Hawaii.
        The activity with the restless but huge systems Corbetti, Tatun, Campi flegrei, and Weishan (Apparently) hasn’t changed at all.
        The calm before the great storm! This is a good reboot period so I will continue my dark musings. Conspiracy theories can only sustain me so much and with all of the material this year. Maxwell’s arrest, the pandemic, politics, and bigfoot has filled my meter for the moment.

  8. More footage from Sangay, these are clips from inhabitants of nearby towns.

  9. On the subject of terrifying eruptions. Santorini/Thera may have given us the word Tera.. Terrible. and on with the others. It was certainly a game changer for the Mediterranean civilizations at the time.

    • The poles are very convective
      Probaly because the atmosphere is much colder there. And lack of equator jetstreams that draw out the thunderstorms into bands.

      I hopes one day there will be a new atmospheric probe, with a camera on, always been curious how Jupiters disturbing bottomless abyss really looks like! the hydrogen scattering skies are probaly blue.
      The convective cloud regions maybe very Earth looking?

    • Ummmm rain, hailstones and snow falling into a bottomless pit where it evaporate in the hot depths, rises up and forms clouds again.

      The lack of surface is quite disturbing.. But its a gas giant after all

  10. I might be wrong, but looking at the deep quakes beneath Vatnajökull glacier in general, we are seeing another influx of fresh magma from the hotspot. And there is a clear uptick in seismic activity at Grimsvötn, so the volcano might erupt very soon.

    • Yes Grimsvötn is about to blow soon: the upper magma chamber is quite enlarged now.
      Coud be a surtseyan Island phase in the caldera, If we gets a large eruption thats slower than 2011, but lasts many weeks.

      • Maybe this is where it finally turns from Grimsvotn into Grimsbunga 🙂

      • Yes perhaps
        Grimsvötn haves a very large deep supply .. and open conduits. ( the SO2 emissions are massive now )
        It woud not supprise If it does something long lived now

      • I don’t think that this will happen. The volcano will evaporate most of the lake and will start growing from there. I can’t imagine that the meltwater will submerge the erupting volcano.

      • 2004 was pretty much violent surtseyan all through, had it continued it woud form a tephra Island in the meltwater lake.

        1998 was even more gentle

        • Hawaii is mostly built from pahoehoe shields, it would seem the only reason Grimsvotn is different is its icy environment and that is all. Kilauea has also done eruptions comparable to the 2011 Grimsvotn eruption too, very similar volcanoes in all likeliness if you take out the ice then Grimsvotn starts frequent small eruptions and builds Grimsbunga.

          🙂

    • Dirk S
      It will be like Surtsey but in Grimsvötn. First surtseyan – pheratoplinian.. then an ash island hill grows out the meltwater lake. After that lava fountains out building a tuya.

      • OK, but in that case the “Surtseyan” phase will last only a few seconds. 🙂

    • Think you are right. Two swarms of deep quakes. May be signs of fill up from below. Exciting!

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