Chiles-Cerro Negro: The Final Swarm

Chile-Cerro Negro, Colombia.

I’ve been tracking Chiles-Cerro Negro for almost 10 years now and it’s been an interesting ride to say the least, full of great highs and terrible lows. My odd relationship with this volcano is going to be on pause and I will be exploring other volcanoes. As such this will be the final article on the volcano unless it erupts. (I’ll keep you updated in the comments.) I’ve written several articles about this volcano already but I am not happy with their quality. For one I was extremely excited and under a lot of unrelated stress at the time so I wasn’t being very articulate in conveying my ideas. Second, the situation at the volcano has undergone several important changes and developments so we have plenty of new information. This will be my most in-depth analysis on the volcano so you don’t need to read past articles to understand the current situation at CCN.   As you might know, I’ve had a bad feeling about this volcano for years, ever since the volcano first made headlines in 2014, there was just something off about it and as the years have passed this volcano has only gotten scarier in my opinion. This volcano is actually a very clear candidate for a future caldera and I will stand by that statement. In order to understand why I am making such a bold statement, we need to go back to the beginning.

 In the Pliocene, lava flows started to pour out from deep below at what would be the border of Ecuador and Colombia. A volcanic field was in the making, and soon 2 major volcanoes would be formed, Chalpatan and Potrerillos. Unfortunately, there is little information about the eruptive history of Chalpatan and no information about Potrerillos but these two volcanoes are among the few large calderas in the northern Andes, both being around 6-8 km in diameter, However these volcanoes would lose steam rather quickly and far as we know both volcanoes only produced one major caldera eruption with Chalpatan’s taking place around 2 million years ago. Oddly around the same time these two volcanoes started to wane the two cones of Chiles and Cerro Negro on top of the Pliocene lava flows and a  new volcano would be constructed. After years of effusive and explosive activity, the Chiles volcano stopped erupting 160,000 years ago and with few, if any eruptions at the Cerro Negro cone. However, despite no surface activity, the region holds immense geothermal potential as there 3 strong hydro-thermal chambers, 2 at CCN and 1 at Chalpatan. 

Before we talk about the recent swarms, we must ask 1 question as an eruption grows more likely, why now? Why couldn’t the volcano erupt in over 160,000 years and why would it erupt now? A 160,000-year dormancy between eruptions at a volcanic system is rare, so rare that I can’t actually think of any more than 3 or 4 other volcanoes where this could’ve happened and none of them were stratovolcanoes. The volcano doesn’t look like it’s lacking any life now and the chamber has a higher melt percentage than other formerly dormant volcanoes so what’s going on? Once again, why is Potrerillos and Chalpatan having volcanic quakes and inflation directly related to Chiles-Cerro Negro? I think we can answer both questions. First off, these volcanoes likely weren’t always connected but they formed very close together and likely shared a deeper source.  When magma ascends, it “chooses” the path of least resistance just like all fluids would do under similar circumstances. What decides where this path is, depends on the geological setup of the region. Usually, the path of least resistance is in the vertical direction but this doesn’t always have to be the case. I am thinking that the reason why none of the volcanoes erupted in the past 160,000 years is because the volcanoes started to merge and magma flowed laterally instead of vertically.

The merging of 2 volcanoes sounds dramatic but it doesn’t have to be. As 2 or more chambers get closer, it would gradually become easier for magma and their associated products to move sideways thus relieving chamber pressure without an eruption. If more pressure is lost than gained during the merger, an eruption is completely impossible. This process is usually seen in rapidly developing volcanic regions with relatively high rates of supply (Katmai, Agung & Batur, Samalas & Rinjani, etc) so these mergers usually start and finish relatively quickly.  I don’t think our system had high enough rates of supply for a quick merger. This system is millions of years old with nothing very impressive on the surface!  Kikai, Toba, Katla, Campi Flegrei, and many more have done more in 100,000 years than this system has likely done in 2 million+ years. Slow supply equals slow merger and it is already hard for magma to break through the crust at CCN because the crust is elastic and compressive, not something that cracks or ruptures easily. Even after the merger was complete, it had been so long that volcanic vents had been sealed shut and the volcano was completely plugged. 

Alpha and Beta Swarms

Chiles, Potrerillos, and Chalpatan were all considered extinct up until 2013 when the magmatic intrusion began and the first seismic crisis started. The IGEPN and SGC set up monitoring stations and alerts were raised. The swarms started in November 2013 but it wouldn’t peak until Autumn 2014 when over 250,000 quakes were recorded in just 2 months! Due to limited monitoring, a lot of earthquakes weren’t located but they seemed to be mainly taking place to the SW of the Chiles cone. At the same time, inflation was recorded over not only CCN but also Potrerillos to the SE as well. The seismic crisis would wane but the inflation would remain constant and actually intensify along with moderate seismic activity. The volcano was alive but how alive was the question. After all, the volcano hasn’t erupted in 160,000 years, after the crisis ended no one thought too much of the system, the inflation was widespread but not very fast so nothing seemed too abnormal. I was under the impression that the volcano would do a slow resurgence before it would erupt again if at all. I wouldn’t notice a lot of oddities concerning the volcano until the second swarm started.

After over 2 years of relative quiet, another uptick in seismic activity began in 2018 and lasted until the end of 2020. On an ironic note, the least intense swarm recorded at this volcano would be the one to seriously catch my attention. Most of the quakes took place at CCN proper in the beginning but as the swarm progressed, more and more quakes would take place at Potrerillos and Chalpatan. Around 200,000 quakes would compromise this swarm making it much weaker than the last but still very significant. Despite this swarm’s relatively low intensity, it would produce more fluid-based earthquakes than its predecessor by a wide margin.  While I tracked this swarm I started to have major questions. First off, why was there more uplift at Potrerillos then at CCN and why wasn’t more seismic activity taking place at Potrerillos if that is where the bulk of the uplift is? What is causing these deep LPs( around 25 km below the surface or more ) and why are they clustered away from the VT quakes and inflation to the NW of the Cerro Negro cone? This swarm never got an official explanation but the IGEPN postulated that the changes of pressure within the magma reservoir were the most likely culprit. Inflation didn’t get faster, no tectonic quakes, and the hydrothermal systems didn’t seem to change that much so whatever caused the swarm was expansive and significant but subtle at the same time. 

As you can clearly see, the area of inflation is actually very large, and we have new studies concerning the size of the magma reservoir. The studies give the chamber the dimensions of 15 km wide and 8 km deep which give a volume of around 1,400 km3 with 14% or 196 km3 of melt. These are just 2 studies so this measurement is not absolute but I am very sure that this number underestimates the chamber’s size. The dimensions that this study gives for the magma chamber are substantially smaller than the inflation area. If you were to use the dimension of the area of uplift i.e. 25×15 km as a proxy for the magma chamber (assuming that the melt percentage and chamber depth is correct), you’d get around 2,300 km3 with around 322 km3 of melt. The first studies on volcanoes are usually the most inaccurate but in any case, evidence is supporting my claim that this volcano is far bigger than it looks. 

Quiet Period

After the Beta swarm ended, inflation abruptly stopped and seismic activity fell to new lows and for the entirety of 2021, nothing major happened. I’d honestly thought that the intrusion had ended when it took place but something still didn’t seem right to me. As Chiles-Cerro Negro waned, the nearby volcano of Cumbal to the north grew more notably agitated. Nothing major but nothing insignificant.  This along with continued instability on the inclinometers gave me the impression that CCN wasn’t quite finished. The current seismic activity at Cumbal is driven by a hydrothermal system that is influenced by regional faults. CCN and Cumbal share the same regional fault system so it’s not a crazy claim that Cumbal would see a modest increase in activity due to the unrest at CCN. However if Chiles-Cerro Negro caused the uptick at Cumbal that would have to mean that it significantly destabilized the regional faults in its quietest year.

This is actually supported by the inclinometer data, as the Cerro Negro Inclinometer showed insane motion for 2021 shifting over 45,000 micro-radians in 1 ½ years! Sometimes moving at speeds of 150 micro-radians a day! After consistent reports of this data, I have no reason to suspect a broken instrument.

Gamma and Delta Swarm

  In 2022, another swarm would begin and would be the most energetic swarm since the seismic crisis back in 2014, starting at May and lasting into October,  consisting of around 180,000 quakes. Once again, the number of LPs and other fluid motion quakes in this swarm beat both of the past swarms combined. The formerly deep LPs shallowed greatly from 32 km below the surface to just a few km at depth.  Fast uplift began in April rising at rates at over 3x the speed of the 2014-2020 inflation period. While no official explanation has been given for the cause of this swarm it would be safe to assume that ascending magma played a major role in this period of unrest. Somehow, uplift stopped again in Nov 2022 and seismic activity subsided. One might think that after the insane movements on the inclinometer, this swarm would bring dramatic shifts on the instruments but on the contrary! The Inclinometers showed less instability during and after this swarm.

Inflation would begin again Feb 2023 but would either stop or wane by the end of March. Following the uplift would come the most recent swarm, which began abruptly on March 9, peaking as soon as it started on March 10 and 11. This swarm didn’t last, only lasting 3 months, with total quake numbers roughly reaching 190,000.

 You may have noticed a trend with the first 3 swarms, they all started off kind of slow but gained in intensity after some time, peaking then slowly losing intensity before the swarm ended. The quakes took place all over CCN, Potrerillos, and even Chalpatan at times.   This swarm was the weirdest because as soon as it started it peaked and the quakes were mostly concentrated in one area. Inflation preceded both the 2022 and the 2023 swarm which is also something we don’t usually see. Since 2018, there’s been a change in activity every year with major swarms for 4 out of 5 years since then of ever-increasing intensity. So whatever caused the 2018 swarm marked a changing point in the volcano’s unrest. You’ll also notice that one area saw the most quakes in all 4 swarms and that area is near an intersection of several regional and local faults which is almost certainly no coincidence.

There are three options, either this zone is where a volcanic vent is forming, a small destabilized volcanic chamber, or the result of volcanic stress on the 3 faults

Future Caldera?

Tons of swarms but can we get some explanations? I’ve thought about this volcano for a while and I’ve got an explanation. I believe that the 2018-2020 swarm was the result of stress from the newly merged chamber being pressurized and the 2021 quiescent period was the result of the chamber going past its “safe” pressure limit. When you stretch an elastic object to its limit, right before it breaks it loses its flexibility and stops stretching. It didn’t seem odd when it happened but in hindsight, the quiescent period was the weirdest year for the volcano. Why in the world would a volcano under intrusion stop producing inflation and quakes only for strong swarms to begin again the next year with no clear explanation? I initially thought that the intrusion may have gotten plugged but I’ve never seen or heard of that happening before, and the inflation at this volcano has so far been on/off since 2022 with an atypical swarm for 2023. In both the previous swarms, the quakes started AFTER uplift began, several weeks after which is something that doesn’t typically happen when a volcano goes under intrusion. In fact, when the uplift rapidly accelerated in February 2023, there were no extra quakes or anything more than 14 VLF earthquakes. 

There has been no official explanation for the Gamma and Delta swarms, not even an official guess, or postulation has been given. I have my own hypothesis but I am not in a position to confirm it. It is of my opinion that these swarms were the result of cracks and/or ruptures at the magma chamber, and honestly, I can’t think of any other potential cause. Ruptures at the magma chambers would be preceded by inflation, causing strong earthquake activity including fluid quakes as the magma rushes to occupy the newly made space, and this all could happen without an eruption If this is actually the case then an eruption is more likely than not at this volcano. The sudden stabilization of the inclinometers during 2 seismic crises could easily be caused by the loss of crustal elasticity and would fit with my hypothesis

. Let’s just think about this for a minute, this volcano is likely as evolved as you can get, has no vents, has not produced any measurable gas emissions of any kind, and the geological setup is hostile to volcanoes, working against magma ascension but despite this, an eruption is becoming more and more likely with every swarm and year under intrusion. Just think about the pressure required to punch through 6-8 km of solid rock, that is a tall order for any volcano. If Chiles-Cerro Negro erupts soon then it has likely been building pressure for centuries or thousands of years. Data on the recent intrusion at this volcano shows that this intrusion is not that big and is almost definitely not large enough to break a volcano like this.  This is how large eruptions happen, the condition at the volcano becomes hostile towards eruptions i.e. pressure is gained much quicker than is lost before something breaks, relieving mass amounts of pressure quickly. The volcano has almost all of the markings of a pre-caldera volcano.

  • Evolved system?  
  • Plugged?
  • Long-dormancy?
  • Past caldera events?
  • Large reservoir?
  • Large amounts of eruptible magma?

The last point is the most significant and I can’t answer this question. The amount of eruptible magma is unknown and since this volcano seems to have been lacking large amounts of supply for most of its lifetime it is completely possible that this volcano doesn’t have enough good magma for a large eruption. 

Omega Swarm

This volcano has produced over 1 million quakes from 2013-2023 and chances are that another swarm is going to happen sometime in the next couple of years.  What will the final swarm look like? If we’re assuming that my hypothesis is correct then the final swarm would be preceded by massive uplift. Not 12cm/yr but 12 cm/week or more. Volcanoes that erupt at newly made vents have massive local uplift and there is no reason to assume that this volcano would be any different. The peak uplift speed seen at this volcano was 36 cm/yr so this tells us that if the past 2 swarms were caused by ruptures, they were small ruptures which gives us an idea of how bad the final swarm would be if a small rupture would cause 180,000+ quakes. The fracturing quakes would be followed by fluid quakes and magma would rush to the surface. It would be pretty obvious that an eruption is on the cards. 

It’s possible that this “Omega swarm”  has already started! On August 5th 2023 another(!) swarm would begin and unfortunately, I don’t have enough information on this to make a detailed analysis on it but we have an official cause for this swarm! This swarm is the result of significant disruptions to the hydro-thermal chamber. Which is indicative of either tectonic and/or crustal instability from ascending magma or an influx of volcanic fluid into the chamber. In either case, this means we’re getting closer to an eruption. I don’t know how fast things are going to move from here but this volcano needs to be monitored like a hawk. This volcano has too many oddities and red flags to be ignored. [] []

Tallis, August 2023

112 thoughts on “Chiles-Cerro Negro: The Final Swarm

      • one typo – I think you might be missing the word ‘formed’ in the second paragraph – in this sentence

        the two cones of Chiles and Cerro Negro on top of the Pliocene lava flows
        the two cones of Chiles and Cerro Negro formed on top of the Pliocene lava flows

  1. Fascinating and scary!

    So if and when this goes Boom it has all the possibility of being a big BOOM!!! on the scale of Tambora to, gods forbid, Toba or Yellowstone?

    Oh that could be ‘fun’ /sarc

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    • I doubt this volcano would pull a VEI 8 but I do believe that this volcano is capable of producing a Hatepe or Tambora sized eruption. It all depends on how much eruptible magma is in the system.

      • It might also depend on the stability of the edifice and surrounding crust. For a big eruption, you might also need a rapid drop from e.g. edifice failure in the constraining pressure (e.g. Tambora 1815, Krakatoa 1883)

    • Such a cataclysmic event would certainly redirect the course and resolution of present environmental controversies, wouldn’t it.

  2. Quote: so rare that I can’t actually think of any more than 3 or 4 other volcanoes where this could’ve happened and none of them were stratovolcanoes.

    Mount Haku, Stratovolcano: Age of rock: 300,000–400,000 years
    Last eruption April to August 1659

    Mount Fuji, Stratovolcano:
    Scientists have identified four distinct phases of volcanic activity in the formation of Mount Fuji. The first phase, called Sen-komitake, is composed of an andesite core recently discovered deep within the mountain. Sen-komitake was followed by the “Komitake Fuji”, a basalt layer believed to be formed several hundred thousand years ago. Approximately 100,000 years ago, “Old Fuji” was formed over the top of Komitake Fuji. The modern, “New Fuji” is believed to have formed over the top of Old Fuji around 10,000 years ago.

    I believe that Las Cañadas, Tenerife also has a history like that. El Teide also a

    This is important proving that your assumption is not far off at all.

    • I think that when it says stuff like that where the age of rock is ~400,000 yeads old, I alwaus assumed it meant the age of the oldest known rock not that there was a gap of that long before historical activity.

    • I think I know a few cases from large calderas with longer dormancies. There is Acoculco caldera in México which produced the rhyolitic Tecoloquillo eruption 700,000 years ago after 300,000 years of dormancy. It was a larger, and particularly more explosive, eruption than usual, but not a caldera-forming event. Then there is Valles whose last eruption 60,000 years ago came after 500,000 years of dormancy or so. Valles’ eruption was relatively normal for the volcano, a VEI 6 rhyolite eruption followed by a lava flow of a few cubic kilometres. And lastly if Tambo Quemado is an eruption of the Laram Pukara dome then it probably follows a dormancy of over 1 million years. These are all rhyolitic systems with voluminous resurgent domes, and a ring of lava domes surrounding the uplift, so they are a different kind of system from Potrerillos.

      There are also volcanic fields that go for very long dormancies. The last erutive period of Leucite Hills (a field of very rare lamproite eruptions), happened after 900,000 years of dormancy following the preceding activity, eruption of Leucite Hills are always minuscule regardless of the dormancy. Or the likely last two eruptions of the McBride volcanic field in Australia, the Murronga and Kinrara eruptions, happened with a 150,000 year dormancy in between, McBride eruptions are always huge.

      • Added to this the “top three” (my top three) supervolcanoes of the world, Yellowstone, Toba, and Tatio, are all in similarly long 60,000-80,000 years long dormancies, although all three of them have very active hydrothermal systems.

          • Tatio is a name I created in this article:


            The Tatio system would refer to the magma chamber that supplied 4 giant rhyodacitic domes/flows in the Altiplano-Puna complex, including the massive 26 km3 Cerro Chao flow. Cerro Chao is unique for its volume and enormous thickness, over 300 meter thickness of lava despite being a single sheet supplied at relatively high eruption rates. There are two strong geothermal fields, El Tatio and Sol de Mañana in the area, El Tatio being one of the most important geyser fields in the world, and the space between the two geothermal fields is elevated and faulted by a number of grabens. Presumably this is the location of the magma chamber, an inflated dome that spans El Tatio and Sol de Mañana, and also including one of the domes. The other three domes I now believe are satellitic and outside the magma body.

          • Wow, thank you!

            Honestly this answer was so much better than what I was expecting, lol. I was assuming perhaps Tatio was a Spanish name for a system known as something else more commonly in English, but the actual answer was SO much more fascinating.

            And thanks for linking to the article, this place has such a mind boggling back catalogue of information to go through. VC is one of a kind…

          • Like of course you named your own enormous magma chamber in the Altiplano Hector, you absolute rockstar.

            And now I have my reading material set before bed.

            Very glad I asked =).

      • How do we know these pre-eruptive dormancy periods for any of them other than Leucite Hills? For example, if Tecoloquillo had many small eruptions but no medium to large ones from 1Ma to 700Ka, and the ejecta never got far from the vents, the big one at 700Ka might have wiped out all evidence of those smaller eruptions. A lack of more distant ashfall from Tecoloquillo during that interval could rule out larger eruptions but not, I think, small ones. Would a hypothetical VEI3 Strombolian lava-sputter that stayed within 1km of the vent 400 years before the big one have left any surviving trace? Would we know about it?

        • That is a good question. You can’t be fully sure, but you can have a large degree of certainty. You would need to make some reasonable assumptions. You would need to classify the vents as monogenetic or polygenetic. If the volcano has a monogenetic-vent behaviour, then each eruption is represented by a crater or lava flow. If all the vents are dated, then you have the full number of eruptions. A monogenetic vent is a plug, a lava dome, a maar, a cinder cone feeding a lava flow, a low lava shield with one vent. A polygenetic vent is a stratovolcano, maybe a large ash cone if formed by individual explosions, maybe a tall dome complex with a thick pyroclastic flow and debris avalanche apron, or tall, symmetrical cone with interbedded lava flows if constructed by paroxysmal style activity. Valles is a ring of simple lava domes that lack complexity, so they appear to be monogenetic, all the lava domes are dated with precision so the full eruption history “should” be known in detail. With McBride you have low lava shields, and the only two young-looking ones are dated. In Leucite Hills there are plugs and small flows, all dated, I think. Acoculco is similar to Valles, and while not all vents are dated, the dating is still very dense, probably dense enough to show that there was a main period of activity where most eruptions happened, and then an outlier (Tecoloquillo) that happened much later.

  3. If we look at wo Jima (Ioto), the next VEI 6-7 will be around several hundred years.

    On the other hand I think CCN could also make a VEI 6. Do you think it could eruption within 1 and 5 years?

    Thanks for you answer

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    • It would seem that the current destabilization of Hyrdro-thermal system isn’t caused by an influx of magmatic gases but by crustal and/or tectonic instability in the surrounding region. I am thinking it could erupt in a couple of years but that’s just a guess at this point. The previous swarm caused several surface cracks and fissures, the crust is weakening but not at the point an eruption is inevitable or we can predict when it’ll occur.

    • … great, the Dragons are mining again. I knew I should have put that shovel away…

      • Hi Lurking, I know you’re a plot maker/data finder – is the data there to get a nice 3d rotating plot of those quake swarms over time ?

  4. Good piece, btw. And certainly the right instinct of yours to keep an eye on Chiles-Cerro Negro.

  5. One concern I have is the whole complex of Cerro Negro, Chiles, Potrerillos, Chalpatan, and area in between is only about 400 km^3 and the associated bulge other than the two small peaks averages <1km tall optimistically. Like the combined volume of addition+doming for the entire complex is similar to Mt. Adams in Washington, and several times less than Crater Lake, Pinatubo (main peak is small, relatively low elevation, but its bulge covers 1600 km^2), Katmai complex, much less Tambora (that is a *monster*). That may still be optimistic as it is part of a broader line of high ground it pretty seamlessly transitions into elevation-wise.

    If the chamber is really 8km deep, I imagine it must be rather dense and chilly on balance. Or I suppose it is quite possible it is rather irregular in shape so much of that area is native rock. Chalpatan seems like it was fairly unimpressive given its width, only ~150 meters deep and slope around it is not much. 10km^3 DRE is pretty generous for that event. Like could this throw out a VEI 6? Sure. Seems quite iffy though for a VEI 7. Either of course assumes the whole thing is even liquid enough for much of the theoretical volume of the magma chamber to occur. Seems pretty likely for it to erupt small. And even being reasonably liquid is no guarantee. Like volcanoes of course sometimes blow spectacularly after long dormancies, but small eruptions or effusive ones are quite common.

    Like is it interesting and worth keeping an eye on? 100%. Activating system at risk of a VEI 6 is nothing to laugh at. I'm just doubtful it has much realistic odds of being the next Tambora.

      • That’s an interesting point, this system is very unimpressive on the surface, the only reason the chamber is so big is because of a lack of surface activity and a possible merger. I am not sure about the quality of the magma but a large magma chamber and a decent amount of melt is present so this volcano is not normal in a lot of ways. Kind of wish there are more studies on such a tricky volcano

  6. Thank-you Tallis for your description and analysis!
    If we look back on Pinatubo and St. Helens, the first initial eruptions were hydrothermal/phreatic eruptions. Small compared to the main eruption, but the beginning. Mount Mazama (Oregon) maybe had a similar development like CCN that produced the present Crater Lake. Another example is Tambora 1815.

    • RE: “Another example is Tambora 1815.”
      Hmmmm. Might just get another classic ‘ghost story’ out of something like that.

  7. It seems two be right in between – that’s to say not to far from – two prominent neighbours, Ecuador’s Reventador, eruptions ongoing since 2009, and Colombia’s Galeras, last eruption 2012-14. Of Galeras wikipedia says:

    “Two major caldera-forming eruptions have occurred, the first about 560,000 years ago in an eruption which expelled about 15 cubic kilometres (3.6 cu mi) of material. The second some time between 40,000 and 150,000 years ago, in a smaller but still sizable eruption of 2 cubic kilometres (0.48 cu mi) of material.”

    So, the whole area is continuously active with big time spans between bigger eruptions.
    Because of Pasto with at least 450.000 inhabitants Galeras became a Decade Volcano. Chiles and Cerro Negro don’t seem to have a major town nearby. Cumbal, Colombia seems to be the next town, about 30 km as the crow flies.

    Chiles-Cerro Negro don’t seem to be prominent on maps of volcanoes. This is like the unsecured crossing. When a person is run over a red light is installed afterwards.

    • I wish it wouldn’t be your last post on this, Tallis.

      I think an imagination what a VEI 6/7 could produce as consequences would be interesting as this is near the equator.

      In my country where most young people know today (or believe they know) where best to eat and what, they might yawn and say “volcanic eruption in South America – big deal”, until the food becomes too expensive. The whole chain is to be taken seriously as it might have contributed to the extinction of the longnecks.

      This one died out at the end of the Jurassic though, it seems:
      Colombia’s longneck Perijasaurus lapaz, found recently

      • I’ve been wanting to write articles about other volcanoes, like Katla, Udina, Tatun, and more but every time I start considering it CCN does something that steals my attention and then proceeds not to erupt! Like a toxic friend, it won’t let me find new friends while not delivering what I need. I am putting my foot down.

      • You want a VEI7 near the equator, try Tambora and Krakatoa’s VEI 6 was quite destructive.

  8. Thanks for a nice article Tallis! It really looks like this has the potential to do something scary in a not too distant future.

    Regarding the volume of magma, I’m a bit skeptical.

    “These are just 2 studies so this measurement is not absolute but I am very sure that this number underestimates the chamber’s size. The dimensions that this study gives for the magma chamber are substantially smaller than the inflation area. If you were to use the dimension of the area of uplift i.e. 25×15 km as a proxy for the magma chamber…”

    Here you need to consider the fact that the whole ground inflates like a balloon. The area of uplift will be much larger than the horizontal dimensions of the magma body. Here’s a schematic illustration of what to expect:

    To properly assess the dimensions and depth of a magma body, one has to look at both uplift and horizontal displacement and match that to some model parameters. Using the entire surface area that has been affected is simply going to overestimate the extent of the magma chamber. I think the numbers from the study are probably closer to the truth than the numbers you give here. Other than that, a very interesting read.

    • The referenced article states that the dashed line shows the surface deformation in an exaggerated way; so, you cannot infer the relative volumes of the intrusive body and the surface deformation. I think that the purpose of the illustration is just to show the form of the uplift, not the volume.

      • Exactly! And my point is that the shape of the uplift covers a larger area than that of the magma chamber.

        There are precise models for the deformation. If a basic shape is assumed, then the size and depth of that shape can be inferred from the surface deformation. The dashed line is as you say just an illustration.

  9. Even if this is just an effusive eruption it is still significant, Chilles and Cerro Negro arent small domes they are actual proper mountains, so either the eruptions last for years or more, or we get to see a new mountain literally form before our eyes 🙂

    I imagine it being something like Bagana but perhaps stickier. There could be some explosive activity but volumetrically minor. Santiaguito might be another good comparison. I think for really huge eruptions long dormancy may actually be a negative as it crystalizes the magma and makes it more viscous and unavailable to erupt. Lots of very large calderas are also very active volcanoes and erupt frequently, including some that are qualified VEI 7-8 monsters. Kikai, Aira and Aso are all supervolcanoes, Aso even got to VEI 8, and all have erupted in the past couple years.
    Dormancy may only be a key factor if the volcano maintained high supply without any major eruptions, so a lot of magma can build. Otherwise you are basically left with a hot pluton that needs to be remelted, which may be the requirement for CCN to become a VEI 7.

    • “Even if this is just an effusive eruption?” The volcano hasn’t started erupting yet! It’s been ages since the volcano erupted, so long ago that the volcano’s previous eruptive history likely doesn’t speak to the volcano’s current potential. The current stress at the volcano is caused by magma trying to break through the thick and elastic crust not by the stress from the magmatic intrusion which is only modest in size by most accounts. You need a significant volume of good magma to cause these conditions. I can’t see uneruptible mush driving the conditions we are at the volcano now.
      According to my hypothesis, this wouldn’t be your normal caldera eruption, and not really comparable to Aso or Kikai. The only reason why this volcano is so big now is likely that 3 reasonably developed volcanoes slowly merged and got a major plug. This volcano hasn’t had a significant eruption in 160,000 so all of the supply went into making this volcano big. I doubt that this volcano will be a repeat offender unless it merges with another nearby reasonably developed volcano.

      • Thats why I said -if- it is only effusive 🙂 although I think it is not unlikely to erupt.

        The comparison to those calderas was not to imply that is what CCN is like, but to highlight that eruption size is not necessarily related to the activity level of the volcano, that it sleeping for a hundred millennia is not a recipe for a disaster when it wakes. I mean, the biggest eruption of the 21st century by an order of magnitude was from a volcano that had erupted not even 5 years before, and numerous times in the past century. And that volcanoes which have done multiple eruptions at supervolcano scale in their history are also among the most active volcanoes on the planet today.

  10. Such a captivating and thought provoking piece; incredible job Tallis! Thanks for concluding your series on Tallis – Cerro Negro with such style and substance.

    While I do hope you revisit CCN in future articles whether it erupts in the near future or not, certainly keep us updated in the comments as things continue to develop. And I do hope to see you write more for VC in general whatever the topic, Tallis.

  11. Thanks for the good overview Tallis!

    I appreciate your updates on this volcano!

  12. This area is silicic-volcanism prone partly because of the subduction of the Carnegie ridge.
    Not sure if this link will work but here’s an image I made in Google Earth showing some known volcanoes in this particular area, very closely spaced to one another too.

  13. A real-time earthquake map like the one in Iceland or the volcanoes in the Canary Islands would be useful.
    But it probably seems that in these countries they are so poor that they cannot afford even that.
    Just an update every now and then on earthquakes with magnitudes greater than 3.0.
    I agree that this volcanic system will probably produce a caldera similar to Quiltoa, perhaps even with a lake.
    It remains to be asked when an eruption could actually occur, it is a rather interesting and intriguing volcanic system.
    Excellent analysis.

  14. at 5:08 local time shows strange ground mist on the ground around the Litli-Hrutur eruption site but on new ground untouched by the eruption. The camera operator took a long look at 3 areas of this unusual ground mist not sure what to think about this.

    • Definitely coming up from the ground, watched it carefully on 1.5x magnification, see

        • I watched for almost 2 hours, you could see the mist coming up from the ground in small tendrils which indicated fumeroling. I took a video showing this. There were 3 areas where this was occurring. The one in the foreground slowly migrated to the left of the picture before fading out around 7 am.

        • A person in the Iceland geology FB group contacted me and sent a video he recorded on July 10th or so before the eruption. It is “Hverinn eini” or old steam geyser, which has been known for quite a while to local residents. Interesting that the activity had picked up to the degree that the camera operator was panning and zooming in on 3 areas, not just this one. I believe that the steaming is connected in some way to the outgassing activity at the cone

    • Looks like burning moss smoke, but 3 areas? I wish that they had a playback feature so we could go back to the hours of 04:00 – 05:07 am to take another close look.

    • Find a way to show Just Icelandic, he might fly over the area with his thermal drone. I know he has been on here a few times though so perhaps no need 🙂

  15. Very interesting morning watching the Litli-Hrutur camera. Around 5:07 am 3 patches of white mist (maybe burning moss smoke?) with the camera operator panning around to look at all 3 in high detail. By 7 pm they are all but gone. Around 6:47:23 a white cloud appeared at the top or behind the top of the highest mountain in view as a dense white block and it then rose up and dissipated but a center core like a emitted center was the last to disappear. Then before 7 am three iceland sheep appeared in the extreme bottom left of the camera view. I wish that the operators would have had playback on this camera. Also the cone is smoking this morning too

    • Carefully considering the 111 minutes I have been watching this via the webcam, I think that the white mist is water vapor, not moss smoke, as it evaporated without leaving residue in the air. So we have some hot ground out there, over towards Driffel. I cannot seem to locate the exact location of the webcam using google earth, but it is somewhere near Driffel and Trolladyngda. This would help to exactly locate where the hot patch is.

      • It’s hugging the ground too much to be mainly water vapour? Could have SO2 in it? Based on seeing it again tonight.

        It’s a good demonstrator of how volcanic gasses accumulate near the ground. If I’m right about the composition, you would not want to hang about near it for too long. A bit problematic if it’s not easy to see in daylight.

  16. It is about here, more or less 🙂

    I dont think there was any notable activity in this area before or during the eruption, but still interesting

  17. And the preliminary results from the field trip to Askja are here:

    “Preliminary results indicate no changes in the gases or waters compared to previous years while further sample and data analyses are ongoing. Visual inspections and temperature and pH measurements do not point to any clear changes in geothermal activity around Askja including in Víti. The observation on 12 August at the edge of Bátnshraun which was reported as a possible steam plume is now recognized as dust caused by a minor rock fall on a steep slope of the caldera wall.”

  18. Just one thought from me.

    When considering the evolution of seismic swarms in caldera systems, remember, you’re not looking for the earthquakes – you’re looking for the *hole* – the place where seismicity does NOT happen. Because that ‘hole’ constrains the location and dimensions of the magma reservoir; the ‘hole’ is the area where the material is too hot and ductile to undergo brittle fracture.

    We saw this very clearly during the recent Taupō unrest episode.

    • Speaking of NZ I’ve noticed that Ruapehu and White Island (Whakaari) never get dropped to Alert Level 0, I’m guessing that’s because of their geothermal activity?

      • Probably to make sure it is always prohibited to go there again after what happened in 2019. Ruapehu though might be more interesting given it is usually a ski mountain.

        Never got to see either when I was in NZ, Tongariro is a very long way south of Auckland as it turns out… 🙂 also no CCS fast chargers south of Taupo until near Wellington.

    • There is a seismic hole to SE of the Chiles cone, in between Potrerillos, inflation is also slower there as well. I didn’t consider that before!

  19. Wow big jump in quakes today, I dont think I have seen it get this high in a single day at any point in the last 5 years.

    • I think it ranks number 6 over the past 5 years, albeit in a plot that may have a resolution of a week rather than a day

      • Yes that is a week, before most of the last few eruptions it held numbers of 100-150 for a week or more, so obviously many more. But nearly 250 in a single day has not happened since the 2018 eruption, or at least since the start of 2019, that I am aware of anyway.

        The way the SWRZ connector is visible makes me think this might not just be another summit eruption, although there is no way to be sure until something breaks.

      • The same timescale for deformation shows a convex inflation = positive 2nd mathematical deduction (accelerating growth):

        If I see it correct, the change from negative to positive flection was in fall 2022. During the eruption in February/March 2023 the flection became additional stronger and growth has been steep since late winter. Flection appears to have reduced to zero (linear trend), but it will likely turn negative again.

        • The Modi model is a good first attempt to fit this. It assumes a round magma chamber which pushes up the ground above and around it. If it grows larger, there is a pattern of mostly linear surface inflation. But if it moves up, the inflation becomes focussed on a smaller area. That gives accelerating inflation in the centre, slower growth around it and deflation further away. It is compared to a Mexican hat pattern. This GPS is probably not directly above the magma chamber, so the pattern suggests the magma is at a depth of perhaps a few kilometres. If it moves up further, you might see inflation reduce but caldera length increase

          • Now the inflation is so high, that sooner or later a downward trend must come. But eruptions often make a sudden disruptive vertical fall.
            Is the magma chamber an old, previously used magma chamber or has a new one been built? Would we notice the creation of a magma chamber seismically anyhow?

          • ‘magma chamber’ is a flexible term. It isn’t (normally) an underground sea – it consists of a mix of magma pockets and solid rock, where the pockets can grow, empty, solidify and new pockets can form, often as sills. It can actually be easier for magma to break a new path through rock than to break into an existing magma reservoir, because higher pressure can form against brittle rock. So if you have a new dike forming, it is often runs parallel to an earlier one but does not meter with it. But that is not an absolute rule: if there is an easier way, magma will take it regardless of any rules.

          • In the case of Kilauea now the chamber actually is probably a single melt body, hence why it collapsed in 2018 and has resumed so fast. The sills and dikes model would fit well with activity in the 20th century but at least after 2008 things have changed. Well, for the shallower system, deeper down is probably more dispersed.

          • How does the extension of magma chambers/pockets work? They have to either melt solid rock or push it apart (an extension). This must supposedly cause tension and quakes.

          • They expand through elastic deformation, when that fails is when something cracks and an intrusion happens. The area around the magma chamber of Kilauea is very hot and plastic, the map looks like it is going crazy but very few of those are proper quakes that would break enough rocks to be felt unless you were maybe right above it. I imagine them being more like when you inflate a balloon and it creaks as it expands. When it cracks for real is when the red stuff comes back 🙂

          • Mogi model?

            In the case of the recent Taupō unrest, we found a simple Mogi model could not explain the observed deformation; it required setting both a Mogi source, and a second, linear, Okada dislocation for best fit IIRC.

          • A Mogi model is a simplistic approximation but useful especially if the data is limited. The more data points, the better the chance to find the deviations from it.

    • This is a piece of a Volcano Watch article on the 1982 eruptions, highlighting what we can maybe expect if an eruption happens out of the current swarm location. Seems no matter what things move very fast, only 2 hours even though this was putside Halemaumau.

      “This brief eruption was followed by a larger eruption beginning at 6:45 p.m. on September 25. This eruption was preceded by nearly 2 hours of increased seismicity and abrupt summit inflation. As magma was rising to the ground surface, it reopened old cracks in and near the eastern end of the Halemaumau parking lot, as the first observer discovered at 5:15 p.m. upon arriving near the site of the eventual outbreak. An obvious asphalt patch across Crater Rim Drive hides this crack today.”

      The swarm is still ongoing, and looks to be increasing if anything, but still focussed under the south caldera and SWRZ rather than Halemaumau.

      • The EQs so far are doing a handsome job of illustrating the extent of the ‘Seismic SWRZ’, while the ‘Volcanic SWRZ’ is as quiet as a mouse. (The architecture of the SWRZ is bizarre and hard to define, it seems there is no connection between the two different SWRZs at all).

        Most likely case is another September 1982 piddlefart eruption, although a repeat of December 1974 would be spectacular. A differentiated-magma eruption like the Kamakaiʻa Hills is the least likely but would be the most interesting.

        • The volcanic SWRZ is basically a crack that goes into Halemaumau, it is probably dead when there is a deeper caldera like now although if the lake keeps filling that will not be the case soon 🙂

          The seismic SWRZ is the SWRZ connector and is probably the same thing as the ERZ connector that has been so extremely active in the past half century. Well, up until August 2021, when it seems to have completely died, and what happened in that month? An intrusion in the south caldera area that also lit up the SWRZ connector like a portrait of the milky way… Whether this means anything long term we cant know but most likely the next eruption will be in the Kau desert and perhaps much more significant than the stuff visible on the surface there now 🙂

          • The seismic SWRZ is certainly overdue. No intrusion since 1981. Since then the ERZ has seen many important intrusions, 2018, 2011, 2007, 1992, 1983, and others. So maybe it’s the Seismic SWRZ’s turn now? At the same time the caldera is still very low elevation and might be the preferred place to erupt.

  20. Shishaldin seems to be in eruption and ramping up, but as usual you can’t see a thing in the webcam, during the day the view was just grey all the time, and I thought Iceland’s weather was bad.

    • Aleutian islands are similar weather.. and despite being far south of Iceland they have just as bad weather, If not worse, being in a coldwater current and marine.

      Both have similar enviroments on the Islands, volcanic glacial landscapes thats now very green in summer. They look so similar in landscapes that a beach in aleutian and Iceland is Impossible to be telled apart 🙂 volcanic landscapes in cool subpolar oceanic locations.

      Aleutian islands sadley receives none of the summer warmth of mainland Alaska so is dog poop weather all year around

    • Shishaldin is the Mount Doom of the Alaska : ) looks very similar when it erupts

  21. Hi Albert how much carbon is stoored inside Earths mantle? soure mostly is iron magnesium sillicates but is there carbon atoms there too ?

  22. I think the melt percentage of 14% is too high for the entire magma reservoir. The value of 14% corresponds to the slowest velocity detected at the center of the anomaly, representing the structure with the highest concentration of melt that can be resolved, rather than indicating the average melt percentage across the entire reservoir. A rough estimation based on figure 8 suggests a value closer to 10%.

    The simplest interpretation is that a low melt percentage implies the melt is locked within a crystal mush, rendering it in an uneruptible state. But there’s a possibility of having unresolvable structures containing significantly higher concentrations of melt that exceed the eruptibility threshold (50%). But then these structures would also contain a much smaller volume compared to the total melt volume in the reservoir.

    • But I suppose it doesn’t matter. I think that crystal mush can be remobilized into eruptible magma in as little as a few years. I hope to I get to see a VEI-7 or higher in my lifetime.

      • I’d say that 10% isn’t low melt but it isn’t that spectacular either. In any case that’s still 140km3+ of magma but I am unsure of that amount of melt would be enough cause this level of unrest. Hopefully we get some more studies on the size of the volcano.

        • Do we think CCN is plausibly waking up for the first time in many thousands of years, or would you speculate it’s had other extended periods of significant unrest in the past? That’s something I’ve wondered about with this system. Regardless, the number of quakes CCN has been generating since 2014 is really spectacular. Hundreds of thousands… even if many are hydrothermal, there had to be a significant change to trigger that sort of major unrest in the historic era.

          I do think we’re heading towards an eruption, otherwise I’d of expected the activity to die down and stay down, which CCN just keeps avoiding swarm after swarm.

          • I think that this volcano has had intrusions in the past, the intrusion is pretty modest in size, barely over 10^7 m3/year. For reference, Campi flegrei is in a similar position regarding a future eruption and it has had a larger intrusion with less hostile crust and is still taking just as long to erupt.

  23. With permission of Hreinn Beck of “Live from Iceland” I was able to make a timelapse video of steam fumeroles located near Driffell. See Two days ago there was a large release of mist from this location and 2 others, so much so, that the camera operator panned around, making it obvious that he/she was surprised by the large amount of vapor/mist release. I stayed up late last night to capture a release, and it worked out fairly well.

  24. Hector

    Finally updated and now at 20 cm in 9 months, the rate is about half the rate of immediately after the eruption last year but at the same time has far surpassed the contraction seen during the eruption too. In vertical about half the drop has recovered. So the supply of Mauna Loa now is somewhere around half the volume of the last eruption has happened since December last year. Considering the 2022 eruption was one of its largest on record at 230 million m3 in only 2 weeks, the current supply could be close to 150 million m3 a year equivalent, which is as high as Kilaueas normal supply. Kilauea though is of course surging so not to be outdone could well be even double this rate presently. None of this is likely to last more than a year but it is equivalent to 450 million m3 yearly supply, more than double the already world leading supply.

    In light of your own analysis on the activity this could be profound, extraordinary even.

    • Yes, this is extraordinary, I think. The inflation rate has been variable. Some spectacular inflation was of 5-6 microradians per month during March and April. But inflation then slowed down, and Mauna Loa also started doing recurrent deflations of its shallow magma chamber, so during May and June there was only 1 microrad/month. During July inflation has increased somewhat to 3 microradians per month, and so far in August we have 4 microradians, although a deflation can hit any time. I think this is the fastest Mauna Loa deformation since at 1975. I don’t think half the eruption volume has been recovered though; the dike will have induced inflation that will have cancelled the deflation from the early part of the eruption.

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