Water, Grimsvötn and Stromboli

The bubble bursting, photograph by Richardo Messina.

After a couple of rather hectic volcanic weeks in the world of volcanoes I thought I would write a little something about two of these events. Namely Stromboli and Grimsvötn, the reason I am cherry picking those two is that they have a common theme, water.



Aerial photograph of the eruption of Stromboli. Note the difference between the white and the ash coloured caused by the water vapour. Photograph by Fernando Caballero.

Unless you have been to Stromboli you will not have a good grasp at how minute a volcano it is. The island itself, which basically is the volcano, is small compared to other single volcano islands. The two vents used to be tiny, and the small strombolian puffs of lava that it emits are miniscule.

How miniscule? Well, at least 2 000 years of recorded non-stop activity has not even made a dent in filling in the scarp after the flank collapse.

This has led people to assume that the volcano is a safe and tame volcano that you can climb and sit down watching its gentle fire fountains. And for fairly good reasons I might add, I have spent 24 hours sitting fairly near the vents studying them.

Problem is in the main driving mechanism. Most people would say that it is the magma moving upwards, but that would only have caused a minor trickle of lava slowly oozing over the crater rims. What produces the fire fountains are the opposite of fire-like lava, it is water.

Stromboli’s magma has an unusually high water content, making the volcano into a steam powered gun hurling lava into the air.

So, what happened was not necessarily that a larger amount of magma entered the system, instead a blob of magma with an even higher amount of water entered the system, and as the water expanded 900 times in volume it emptied out the entire barrel of the volcano in one big hurl.

Depending on how much of this water rich magma entered the system, the new modus operandi can continue for quite some time. So, it is a good idea that the authorities are performing at least a partial evacuation.

The videos of the eruption contain a couple of interesting clues just prior to the big hurl. First you have an explosion as the vent is blasted apart by gasses running before the big lava ball, and you can also see how the increased pressure is deforming the mountain causing a rock-avalanche to run down the mountain due to a partial flank collapse. Yes, it was not a pyroclastic flow as many states, that came later.

If you look at the images of the ash column you can see that it has two distinctly different colours, one is the regular ash from a blast like this, the other is eerily white. The white part is steam from the propellant force.

It will be interesting to see if this was a one off, or if this will be a new pattern for Stromboli.



The newly exposed cliffs of Grimsvötn that has been hidden for 50 years. Image from Ruv.is.

Words like minute, small and minor, has never been associated with Grimsvötn. Basically, only two things are the same between Stromboli and Grimsvötn, that they are both volcanoes, and that both are heavily influenced by water.

If changes in Stromboli’s water content is a local problem, any changes in Grimsvötn’s water treatment is potentially a global problem, and most definitely a problem for Iceland. And something has definitely changed dramatically in Grimsvötn, and I will give a try at explaining what that means.

Up until 2011 Grimsvötn basically erupted the dregs left after the global-impact eruption of 1783. In 2011 the ejecta was juvenile material, and that means that it was hotter and richer in volatiles, compared to before.

If water is the main volatile ingredient in Stromboli, this is not so at Grimsvötn. Instead the volatiles at Grimsvötn is predominantly sulphuric gasses. This means that the lava itself is not overly explosive, and that without the water in the sub-glacial lakes, and the glacial ice itself, Grimsvötn would during eruptions produce fire fountains 700 to 1700 metres high.

The geothermally opened lake shown in red. Lots of ice is floating on top, but it is open downwards. Image grabbed from Ruv.is.

A while ago Andrej made a couple of plots trying to see how the system had changed as represented by location of earthquakes around the upper magma reservoirs.  The plot below shows the potential rim faulting based on the seismic data. The colorbar shows the terrain elevation for the plot on the right side.

What we found was dramatic to say the least. The influx of large amounts of high-temperature magma had enlarged the chamber significantly around the southern magma reservoir. The red square actually shows the area that is used by IMO for the cumulative seismic moment plot for Grimsvotn.

Earthquakes pre 2004 plot. I am using this one since it is clearer from eruption earthquakes. Image by Andrej Flis.

Prior to 2011 the reservoir basically followed the caldera wall, but now the reservoir has expanded 1 kilometre further in an area running from southeast to southwest. Normally this would have been performed by intrusions into the bedrock and it would have been a very noisy process.

Instead it seems like the hot magma has relatively quietly melted the reservoir walls. The reason that this was even possible is due to the ambient temperature of the surrounding bedrock.

Post 2011 plot. It is showing how the pressure induced earthquakes have moved further to the east and southeast shadowing the enlarged magma reservoir. Image by Andrej Flis.

The implication for the available eruptible magma is staggering. We are talking about a further 10 cubic kilometres of eruptible magma that does not show up on the GPS-stations as inflation. Not that there is a lack of inflation over at Grimsvötn, it has inflated well enough in the usual manner after 2011.

This increase in heat and new magma volume has had other drastic effects. It has increased the amount of geothermal energy release, probably with as much as twice the previous wattage per square metre. It has also changed the locality of the release of the energy.

Previously the main energy release was inside the lake, causing constant glacial melt that in turn caused large glacial water outbursts in the form of Jökulhlaups. As the water accumulated below the uniform glacial cover it after a while lifted the glacial ice and the water gushed out through a crack in the caldera wall.

Now instead the main location is around the east, south and western caldera edges. And the amount of energy released is so large that it has melted the glacier enough that rocks not seen for decades, or even centuries, are visible. And there are even a few spots where the glacier has melted sufficiently for the sub-glacial water to come to the surface.

This means that the melt either can go directly out under the glacier without causing lift of the caldera glacial cover, or that the water can expand freely and move up through the ice free (sort of) parts of the lake. In other words, the days of the large Jökulhlaups are over for now since the water pressure can’t build up enough.

The lack of large Grimsvötn Jökulhlaups is a great boon for Iceland, for as long as that now lasts. Not having to worry about the water content of 100 amazon-rivers gushing forth every now and then, makes life a lot simpler.

The drawback? Let us start with the most famous bet in volcanology.


Albert vs Carl Grimsvötn Forecast Bet

Cumulative Seismic Moment plot courtesy of Icelandic Met Office.

This bet was made under the mutual assumption that we could use the previously well-functioning model of forecasting, namely lazily looking at the Cumulative Seismic Moment curve handily supplied by the Icelandic Met Office and combine it with earthquake plots and GPS-trajectories.

This has worked well for the last couple of eruptions and would presumably have worked for every eruption after 1783 if we would have had the recorded data for that period. More data would probably have made our forecasts even more accurate.

Albert came up with 2020 as the most likely year, and I came up with 2019, both of through quite a bit of data wrangling and basic math. The price would be that the loser would have to buy the beer the next time we got around to having a few rounds in person.

The bet was of course made in good fun, and as a means to prove that you can forecast an eruption based on stringent scientific modelling, if you have enough data, and that the volcano does not change too much.

Both me and Albert caveated ourselves heavily on the “change” part, since we well know that if any larger changes occurred, we would both be thrown off by a curveball changing the basic parameters that we made our forecasts on.

I am a stickler for scientific honesty, and Albert is an even larger stickler. And I am quite happy with conceding that my interpretation is made invalid by the changes to the geothermal release and the changes to the upper magma reservoir.

The reason for this is that the method we both used is basically a function of pressure causing the roof of the reservoir bursting at a specific point, and that we could forecast a likely moment using Cumulative Seismic Moment analysis as a tool of measuring pressure increase.

That model did not take into the account the effect of hotter magma melting the sides of the magma reservoir, and presumably at the same time melting the roof of the reservoir, as evidenced by drastic increase of geothermal energy release. At least for me I have lost the bet due to nature throwing curveballs.

Even if I hit the date, it will be for the wrong reasons, so no beers will be claimed by me.

So, now that we are both probably wrong, we can do the fun part of science, trying to find a model for the new conditions that nature have produced. I am therefore proposing that we reset things and make new forecasts as soon as we have put the new possibilities into our respective models.



Another gorgeous gorging caldera rim picture graciously stolen from Ruv.is.

This will be a bit ad hoc since it will obviously take me some time to figure out what the effects will be.

The increased volume might indicate that the risk for another Lakí style eruption has increased, but I do not really believe this since there should not be enough strain yet at the fissure swarm.

Instead I think it is increasing the risk for an eruption even larger than the 2011 eruption. And since the reservoir has expanded beyond the caldera rim, a larger eruption could imply a future partial caldera event. But this is so far just a small possibility, with a 2011 sized eruption being the most likely outcome.

There is also the possibility that the eruption will be voluminous, but not overly explosive, since the eruption will quickly build a cone or a fissure hump sticking up out of the water and ice. This is the solution that would make the Icelandic people happy, since this would limit the amount of ash that they get dumped on their front porches.

One thing is though clear, we will not have a small insignificant eruption when it happens.



201 thoughts on “Water, Grimsvötn and Stromboli

  1. I am happy to claim the Grimsvotn beer..

    Earthquakes can be an art form

    • Nah… You won’t win that easy 🙂

      To claim it you need to write an article explaining how your old forecast is still valid in the light of the changed parameters 🙂

      And that one would have to contend with my soon upcoming revised forecast that will utilize the latest data.

      Much fun to be had before claiming the beers. Unless of course you are coming here soon, or I go to where you are now. Then beers will be had anyways. 🙂

      • My point was that even if I would “win” and it erupted on time, it would be for the wrong reasons. And it would be like I was cheating to win since I feel that I would not deserve the beer since it would have been a fluke and not based on my modelling being stringent and fact-based.
        In my opinion the changes are so large that it is basically changing how I have to look at the volcano to much.

  2. I imagines the 2011 without Ice and water to be like an oversized version of Kilauea Iki 1959 or Etna 2015.
    Grimsvötn without the Ice woud be lovely hot lava fountains.
    But some says its so gas rich that it woud blow up into basalt ash anyway
    The new fresh magma at Grimsvötn is probaly over 1200 C if it melted the bedrock walls from the expanding magma chamber. Also the larger expanded chamber will take longer to pressurize.

    Still there is norhing that should prevent Grimsvötn from forming a permanent conduit up from the chamber and build tuya formation ( shield that grows out the ice )
    No recent Grimsvötn eruption have reached a tuya phase after the ice above the vent have been removed.
    Imagine a huge lava lake in south caldera where an explosive tuya forming eruption built above the water and ice.

    • Carl with souch enormous ammounts of basaltic lava shallow to the surface….
      A permanent conduit up should be possible.

      No recent pherato-glacial Grimsvötn eruption have reached a tuya phase after the ice above the eruptive vent have been removed. If that happens one day.. we haves the settings for a enromous lava lake to form there.
      But I also knows that lava lakes are extremly rare
      Erta Ale is in a very similar tectonic and geological setting rift and hotspot

      • Only diffrence is that Ale is a continetal one ( but Icelands oceanic crust is almost as thick ) and Erta ale is on northen edge of a triple junction boundary

      • There is nothing pointing towards it Jesper. After all, no other Icelandic is behaving in that fashion, and also one would have to remember that Grimsvötn is quite a bit cyclic in its behaviour.
        That being said, it is not entirely impossible.
        It could be argued that the Grimsvötn Fissure Swarm is on a triple-junction, but I will have to get back on that one in another article I have planned.

        • The huge influx of fresh magma into Grimsvötn and the fact that the uppermost magma chamber is very shallow ( makes alot of sense with all the geothermal heat, bedrocks have poor conductivity musy be close to the surface )
          Suggest my scenario maybe true one day
          But the lack of lava layers in Grimsvötns caldera wall suggest mostly it does short powerful exploisve eruptions.
          But its here where Iceland Hotspot is
          My scenario is unlikley but not impossible

        • Hold on — in another comment here you claim not to have any future articles planned. These two comments appear to directly contradict one another. Which one is correct?

    • I have a theory that lava lakes are not actually driven by total lava supply but by the gas content. All the volcanoes on earth that have lava lakes are volcanoes that have high gas emissions, and also dont actually erupt very often they just have an open conduit which is basically a really hot gas vent, erebus possibly hasnt actually properly erupted for millennia, and the last time masaya erupted lava flows was in the 18th century, but both are near constantly active with lava lakes. If said volcano has slightly cooler magma then it becomes more strombolian, like stromboli itself, the effect is the same. Volcanoes that actually have or had a huge supply dont seem to do lava lakes, they just erupt. That is probably because at high supply rates the volcano is able to erupt on that alone, then you get continuous outflow, which makes a lava shield. This shield often has a lava lake on it but the lava circulates because it flows into a lava tube not because of convection, often the lake is temporary, the flow becoming channelled towards the exit tube and the thing crusts over to seal the tube.

      The only volcano that actually has high total magma supply and also has a long history of lava lakes is kilauea, but it is not so contradictory to my theory as it immediately appears. The overlook crater lava lake was fed at very low supply with high gas emissions, because all the lava was erupting at puu oo which was 350 meters lower. When it did actually capture higher supply, it overflowed quickly and acted the same as puu oo, as it did in 2015 and 2018. In 1967 a lava lake formed but it was very different to a stable convecting body of lava, same with 2011 lava pond in puu oo, both were rising up through intrusion of more lava under them, which often erupted out of the peripheral ring faults in both cases. The net effect is that a lot more lava went out and not much went back in if any at all in either case, and when it did go back in a lot more went out through the rift. In the 19th century to 1924 the supply to kilauea was low compared to today, with more magma going to mauna loa so the effect was similar, and the supply rate was more in line with other lava lake volcanoes elsewhere. All these phenomena have the one feature in common of diverting most of the magma elsewhere than into the lake itself.

      All this data actually goes heavily against grimsvotn ever having a lava lake.
      If grimsvotn ever engaged in a long duration eruption that isolated itself from the glacier, it would probably be very similar to the 3 years of tall fountains that puu oo formed in, which is basically a lava geyser.

      • Puu Oo .. was resposible of keeping the overlook lava levels low
        IF Puu Oo did not exist… the 2008 – 2018 overlook lava lake woud get all the pressure of the 0,2km3 yearly influx and pretty much constantly overflow I think.
        Without Puu Oos pressure valve its KIlaueas summit that woud do the shield building.
        And by 2018 there woud be a large Mauna Ulu like shield in Halemaumau with a high standing lava lake feeding tubes.
        The observatory shield in modern era…
        Kilauea is well known doing large and very long lived summit lake – tube feed eruptions that covers the volcano in Pahoehoe lavas. Souch summit lava lake tube feed eruptions can last 100 s of years as Kilaueas base supply can easly compensate for low eruptive rates

        • yea excuse me.. I forgot VC Bar is kind of that place chit chat
          My memory is poor when stressed
          Now back to Iceland and Stromboli

        • Do they have the ability to move the article over to the chat site and provide a link? Give a warning if it continues move to chat site with link maybe even put up a waffle icon.That seems like the best way to resolve these waffle sessions without causing too much grief, they get their say, just not here.

          • I already did, the chat site is the vc bar which is linked in the menu.

      • I am afraid this has not been thought through. Ambrym has an extreme magma supply, and long-lived lava lakes. That lava lakes have high gas emissions is expected as the lava is at the surface. Grimsvotn could well develop a lava lake, especially when filed with fresh low viscosity magma – Iceland has many eruption modes not all of which may be present at any one time. But Grimsvotn’s problem is that the pressure required to push lava into its caldera could also open up the connected rift which at much lower elevation. I would not be surprised though, if there had been a lake present prior to Laki. Same with Katla and Eldgja. Speculative comments is fine, but don’t use fairly random observations as proof, and you final conclusion goes far beyond the data, in spite of what you say. A comparison of volcanoes with lava lakes would make a good post. No need to draw conclusions – just a comparison would be interesting.

        • Yes
          First a premanent conduit needs to be sent up and erupt a hole in the water and ice and pile up an tephra Island in the meltwater lake
          Then the lava lake can form ….

          I wants to see more of Grimsvötns caldera walls that can give us a sense of history of this volcano. Thin Lava layers indicate lava lake activity
          The New outcrop seems only to be loose tephra and tuff

        • You’re conjecturing a *subglacial* lava lake? I don’t know how that would work with the heat, reflexively you would say something would *have* to give; either the ice would chill and solidify the lake, or the lake would ‘win’ and melt the ice cover.

          But any hypothetical lake *must* have been subglacial, otherwise the glow would have been seen and recorded; the records from Viking times are… ‘informal’, but still quite informative, and even moreso for Laki of course.

          • Maybe in the years after laki there was a lava lake, in 1784 and 1785?

          • No an eruption first blasts a hole through the ice and water
            Then it builds an tephra Island in the meltwater lake
            Then the lava lake can form ….there

          • And submarine lava lake is entierly possible too specialy if the convection is fast
            Rock conducts heat poorly thats why submarine flows can tube and flow so far underwater insulated.
            Lava Lakes deep underwater are 100% possible but convection must be vigorous heat loss is faster than on land

      • What if the gas alone was hot enough to keep the lava lake molten, the lava supply then can be minimal, .

  3. To somehow defend Stromboli’s honor here… Yes, the island is tiny, but the volcano really isn’t. It’s almost 3000 meters tall. Erupted volumes are indeed small, but the sector collapse 5000 years ago which removed a good third of the island and a huge chunk under water has been filled about 2/3 in 2000 years, so its still erupting quite a significant amount.

    • Yes Leonard, you are quite correct. But, it in comparison to most volcanoes on the planet it is not that impressive sizewise. The stamina is on the other hand un-parallelled.

      • Indeed Stromboli and Ysaur been doing strombolian burping for 100 s / 1000 s of years

      • On Stromboli not being very impressive size wise I completely agree. Compared to other volcanoes it is tiny… I just found that the text hinted a bit at Stromboli being exceptionally small… Which it isn’t. Sorry, I tend to nitpick when it comes to linguistics / semantics, comes with my education:)

        • A 3000 metre cone is not tiny. Pretty much average in truth. While ‘sea level’ is important to us humans, it’s rather less so for volcanoes. It would be interesting to compare the edifice heights and volumes of, say, Stromboli, Sangay and Mayon

          • Well the height alone says only so much. Etna is only about 300 meters taller than Stromboli, but the overall volume of the edifice is many times that of Stromboli. Stromboli is very very steep and therefore is way smaller at its base than Etna or even way smaller volcanoes than Etna.

    • An aftershock from 1872…

      In a chicken-or-egg conundrum, it’s never been clear whether this region is the site of continuing off-fault aftershocks of the 1872 M~7.6 Owens Valley earthquake, or whether, because the crust is heated, weak, and shocks are abundant, all of the local stress is continuously being released. If that were the case, then the 1872 shock may have been arrested just to the north because it ran out of stress (Stein, 2016).

      Now, the Ridgecrest M 7.1 has delivered the answer: There was plenty of accumulated stress, enough to permit a quake with 3 m (10 ft) of slip. That suggests that one can, indeed, have aftershocks 150 years after very large mainshocks, an argument we advanced in Toda and Stein (2018). This was inspired by the work of John Adams (Natural Resources Canada), John Ebel (Boston College) and Seth Stein (Northwestern University).

      …The biggest loser is a 30-km stretch of the Garlock Fault just south of the action that was hit by a Coulomb stress increase in excess of 2 bars. Remarkably, this section has not lit up in aftershocks. Could this stretch of the Garlock be waiting to go all in one big event?… An end-to-end rupture on the Garlock, if (still) possible, would be in the magnitude 7.6-7.8 range.

      • Hawaii earthquake of 1868 still has some aftershocks even today, which is I think the longest period of aftershocks still ongoing. Its a different cause than the quakes in california though so I dont know if its at all comparable.
        I think that USGS just draw the line until another sufficiently big quake happens at the same spot.

    • Another one from Temblor

      We see that the the 7.1 quake likely brought faults in the Coso Volcanic Field closer to failure, consistent with the abundant aftershocks there. But although the quake also strongly increased the Coulomb stress on a 30-km (20-mile) stretch of the Garlock, most of the aftershocks along the Garlock have in fact appeared in a blue zone to the southwest. Satellite radar imagery spanning several years before these quakes suggests the Garlock may be slowly creeping in the blue zone [Tong et al., 2013], which if real could play into seismicity there, but that signal is within the noise level of the dataset. Satellite radar imagery and other geodetic (surface deformation) data and field observations will help piece together what has been going on, not only near the Garlock but everywhere in and around the Ridgecrest sequence.

    • Anyone care to comment on the proximity to Long Valley Caldera? This is what I posted to another less scientific group. “Searching for commentary on how the Ridgecrest earthquake night have impacted Long Valley Caldera didn’t turn up much, but there’s plenty of technical information on that quake here. Long Valley Caldera, 50 miles to the north, is America’s other supervolcano, and like Yellowstone is restless, still active, and nearing the beginning of another eruption cycle if past geologic history is any indication.”

      • I think there is no risk regarding any volcanic activity. Hydrothermal activity could be affected by earthquakes. It is too far from the main shock but there have been aftershocks some distance away from the original epicentre and these could cause more shaking at Long Valley – in theory. Movement on a local fault can change the water circulation, affect ground-water and/or release pent-up gas.

        • There are volcanoes all up and down the back side of the Sierras (the Sierras themselves are a giant granite batholith) but they don’t do very much except occasional earthquake swarms and hot springs.

  4. excellent reading…. but from a totally unsciency view… Stromboli looks dangerous from a tourist point of view. Not enough area on the island to get away from any really bad explosive blowout. And not enough boats to move the people away fast enough and far enough. and is there any possibility for a Mediterranean wide tsunami from a total collapse? Excuse the apoctaliptical question… don’t want to feed the trolls and please remove this comment if needed… but have always wondered if another Santorini lurked in the Mediterranean. Best!from motsfo, sweltering in record breaking heatwave in alaska at 26C (and don’t forget about my forest fire burdening my air which is almost 100,000 acres)

    • I think that many people underestimate Stromboli because of its usually benign eruption style. But I also don’t think you can compare Stromboli to Santorini in any way. I see the real danger at Stromboli in its very steep build which makes it prone to flank collapses or in general mass wasting events. Those have happened a few times in the past und are likely to happen again in the future. But even if such an event happened, I don’t think the resulting tsunami would affect the whole mediterranean. It would certainly be bad news for Southern Italy, Sardinia and Sicily, but I doubt that Stromboli has enough volume to really cause a tsunami which would significantly affect coasts further away. Maybe the riviera and southern France, but that should be it. Still…. I hope that people are getting more aware that, although Stromboli seems like your friendly neighbor volcano, it can still kill you in seconds if you don’t respect it. If that explosion had happened an hour or two later or would have been directed an a slightly different direction, we would not be talking about one death right now, but hundreds.

      • Yes, at dusk there are hundreds of people at the summit, only 100 yards/metres from the craters. A few shelters (3?), with instructions that “if you cannot reach the shelter, do not panic”! The Skyline webcam is further away, and that got plastered with red hot lava.

        “you can also see how the increased pressure is deforming the mountain causing a rock-avalanche to run down the mountain due to a partial flank collapse”

        Every video/timelapse I have seen doesn’t show the start of the rock-avalanche – the pale rock/dust is already there all the way down to the sea – does anyone know how long it was between the avalanche and the eruption? The Skyline webcam usually have a 24hr timelapse, but it seemed to go missing on the day of the eruption and the day after.

        Looks like it was not much time by this video, taken by Brazilian tourists. They’re watching the rock fall when the explosion happens, and they don’t stay around long to film it!


        • Apparently rapid inflation started showing on the tilt meters about 8 Minutes before the explosion, so I would guess that the avalanche started around that time or a bit later. I don’t have seen any video showing the start of the avalanche though.

        • Before the explosion there were lava flows that apparently reached the ocean, not sure about that last bit but there was heightened activity in the hour before the big eruption, and at least lava flows in the summit area.

          After the big eruption the pressure decrease also lead to lava fountaining continuously in the new crater for over a day with lots of new lava, it looked like an eruption on etna or hawaii, much more than stromboli usually does. Perfect example of rapid decompression causing eruptions that are much bigger than the normal for that location.

          • I mean to say that possibly the lava flows entering the ocean was actually the avalanche they talk about… ?

  5. I’m a bit confused about something you wrote about Grimsvotn (No Icelanding keys on this keyboard…).

    If I understood you correctly, you’re saying that the earthquakes having moved South shows an expansion of the magma reservoir, but you also say that this has likely been a quiet melting process, rather than a more noisy process of intrusion (and then melt?).

    But, would not the earthquakes you are using to identify a southwards expansion be indicative of the process not being that quiet after all? Or are you thinking the process should have been a lot noisier if this was a primarily intrusion-based process?
    Or (more likely), did I miss something and just get everything upside-down again?

    • Right click on the image at imgur and copy the image/link location then just use that in a post on it’s own line.

      Here’s a later view which does now have some small recent Garlock fault quakes

  6. For various reasons this will be my last article, and my last comment.
    It was a good run, and I thank the readers of Volcanocafé for the time that has been.

    Ce la vie!

    • Dear Carl,

      Very many thanks but I fear this place will be very much depleted and made a much poorer place with your absence.

      I just hope this is due to pressure of work/family and not for health reasons, but whatever the cause please accept my good wishes and have the very best of good luck.

      Hopefully you will pop in using an avatar on a few rare occasions.


    • Dear Carl,

      As a “long time lurker/never poster”, I am definitely going to miss you. Grimsvotn has long been a source of constant joy, amusement, bafflement and wonder to me, and so by extension, have you. I sincerely hope that all is well in your world and that we get to hear from you again when circumstances allow.


    • Nooooo!! Sad news! I always enjoy your articles. Volcanocafe will not be the same without you 🙁

    • Sorry to hear this Carl, you have been an anchor of reason along with Albert to keep the ship on track. May the wind be at your back and your path gently down hill.

    • Wishing you all the best Carl and hoping circumstances may change in the future and allow you to reconsider. Your articles and your humour was one of the things that brought me here in the first place. I may not often comment on the subject of the current post but that’s quite simply because I have nothing to add – not that I haven’t read and enjoyed them!

    • Very sad to read this, I really enjoyed your articles and wit. Wishing you all the best, I hope nothing has happened because this is rather sudden. Take care.

    • VC will be greatly impoverished by your leaving, Carl.
      You have done us all a great service, and enriched the quieter hours of my working life in my shop, where I can try to fathom out the mysteries of what lies beneath our feet, after reading your articles.
      I’m very sorry to hear this news. Very sorry indeed.
      But whatever you will be giving your attention to, I wish you all the very best with it.

    • You will be sorely missed, please do pop in from time to time. You’ve penned several of my favorite articles.
      Take care and best wishes!

    • Rumor has it there’s a new site called volcanocarl.org

      • We will all have to go onto it and Greip about his disappearance. Sorry. That’s a really bad joke. I’ll get my hat and coat and leave the building…
        I hope he’ll be back…

    • Noooo Carl, like uppermerseytas I’m a long time lurker, I’m not qualified to comment more than newbie ramblings, but I can certainly say my newbieness has been improved by your inputs. Please come back to us when you are able.

    • Nooooo!! This is your website, or so I thought.
      Your articles will be very much missed.

    • Will miss your deep knowledge and the extra spice you added. Still hope you will reconsider..

    • Right… so one of the founders and greatest contributors leaves the ship. That’s not ok. Carl isn’t answering anymore, so can someone with an access badge to the backchannel please explain this?

      • I don’t want to go into details right now as we (admins) are still discussing the issue.

          • Another long time lurker dismayed by this news. If it was those two they should get life bans. This is Carl’s site. Come back Carl, please. You are its heart and soul.

          • If Carls quit even 10% because of me then im leaving anyway no ban needed though ill probably get one after this anyway. If me being here means every time I talk for longer than a sentence will be met with scores of people who never comment turning up to talk about those two again in completely separate comments as if it somehow makes it less clear who they are referring to, then im not staying around. Nothing personal to any andividuals but this has all gone too far and im putting an end to it.

          • PLEASE allow a man to quit with dignity.
            He chose not to give reasons. Can we not respect that?
            Conjecture on such things seldom helps anybody.

            I too would have preferred him not to sign off. But he did, and that is his business, not ours.

          • Well I, like others, have finally lost patience with the persistent problem. Seeing as he apparently doesn’t want to listen, I’m far from disappointed that he’s gone. Talking about moderation is not allowed in here (which is fair) so I won’t go there but my word I have wanted to!

          • I have been lurking since the start of this blog on the other platform, followed Bob avidly. Just because people don’t comment doesn’t make them any less part of this site. The fact that the debacle over the Hawaii over-commenting drew scores of non-commenters out to complain surely tells you something, Turtlebirdman? Then and now.

          • I have to disagree. I’m not a frequent commenter because to be honest, when it comes to volcanology, I’m out of my depth. The ‘two’ you mentioned, to the best of my knowledge are being criticised for talking about volcanoes too much. So they aren’t the volcanoes you want to hear about? You know what, that’s okay. Some of us still learn something. Scan over the comment, ignore it if you don’t like it. You want to censor intelligent conversation; censor things you don’t want to hear? Do they offend you? Unlikely. There isn’t enough intelligent conversation about volcanoes anywhere on the internet and I for one – and I have a soft/hotspot for Icelandic volcanoes myself so this is not a bias thing – just enjoy hearing people talk about volcanoes, wherever they are, however well informed the conversation. The name ‘Volcanocafe’ implies a certain informality that this discussion belies. My understanding is that this is an informal place for people to chat about volcanoes. This is playground stuff, unbecoming of such minds. Carl, come back, please, you can see the weight of opinion here. The other ‘two’, don’t go either, let’s all learn to get along.

          • Can we please not discuss moderation on the blog. Use our email address to voice any concerns.

            We (admins) consider the this issue closed and relevant persons spoken with. I am hopeful that Carl will return soon, but the final decision rests with him.

    • Almost 8 years is more than a “good run”! You’ve given us all a once-in-lifetime opportunity to learn and digest all that is great and interesting about volcano’s and geology in general. Wishing you all the best, as I sense this decision came on rather suddenly. Hopefully we’ll hear back from you from time to time to let us know yer OK.

  7. Carl? You’re leaving us? Nooo! I have so much enjoyed your presence, science and sense of humour. And the Guatemala connection too.
    I hope you have a change of heart and return in the not too distant future. After all, I’m sure Grimsvotn will want to hear from you after she has done her thing.
    Good luck and thanks for all the biscuits.

    • Seconded Hope whatever is behind this all comes to pass quickly and Carl reconsiders.

  8. Oh, Carl! Don’t know what’s going on but i’ll always wish You the Very Best! ps and a rather flippant remark made to fond friends is “Write when You get work.” so………….. hope to hear from You in the future.
    a sadder motsfo

  9. Carl,

    “Instead it seems like the hot magma has relatively quietly melted the reservoir walls. The reason that this was even possible is due to the ambient temperature of the surrounding bedrock.

    The implication for the available eruptible magma is staggering. We are talking about a further 10 cubic kilometres of eruptible magma that does not show up on the GPS-stations as inflation.”

    Sorry to intrude, but could you enlarge on that? (no puns intended!)

    Talk volumetrics; magma has melted the reservoir walls, you say. Fair enough. But solid or liquid, the material takes up around the same amount of space. So there’s no net volumetric change. No new material, just a change in the status of existing material, from a solid to a more liquid phase. But does that render it eruptible? What does the literature say? Are you saying it’s not just been melted, but recharged significantly with volatiles, to render it eruptible? Not just melted wallrock, but turned back from lava into magma, so to speak?

    • this is also an interesting question I hope someone can answer 🙂

  10. I’m not sure if if this has been discussed but is buried in the comments, but could this explosion in any way (aside from coincidence) be related to the minor explosion at Etna just prior? I know they’re not near close enough to be influential on one-another, but sometimes it would seem to the unscientific-minded observer that those two volcanoes are communicating with one-another.

    Also, does the little observatory at the eastern edge of the Sciara del Fuoco have a proper name, and am I correct in presuming it is a volcano observation station?

    • No My Dear friend Spike… they are two magmatic systems over 100 km apart
      The Geology of that arera is extremely complex

    • @Volcanohead No no no sir… @EtnaBoris has hands full of local truthers suggesting such a thing.
      They both erupt so frequently that overlap at times is a given certainty.

    • Twitter cone 😀

      I would say that frequently one erupts whilst the other is at background levels so what happened on those occasions (Had they fallen out and not on talking terms frequently lol) .

      Seriously tho they both are extremely active volcano’s so overlap is certainty over time.

      Much love from Twitter Vesuvio 😀

    • @Spike Page.

      The much hyped Eyjafjallajökull – Katla relationship is quite similar. Katla is such a frequent eruptor that usually, anytime Eyjafjallajökull erupts, Katla has already just done so, or is close to erupting all by itself.

      Looking at the quake stacks under all the edifices reveals that each system had its own separate stack. Eyjafjallajökull, Godabunga, and Katla. All angling away from each other.

      The only “solid” connection is from the Fimmvörðuháls vents to the Eyjafjallajökull upper chamber. I did find an almost connection in the quake line towards Godabunga, but it never connected.

      • …however, Huluhraun did prove nearby volcanoes can interact via dikes. (Though Katmai’s summit collapse sort of already proved that when Novarupta drained its chamber in 1912.)

        Technically. This makes Novarupta a side-vent of Katmai.

      • Functionally. This makes Novarupta-Katmai similar to Huluhraun-Bardarbunga. Though The dike that was involved in all this came from a 3rd system and involved Bardarbunga incidental to it’s path. Griep was just a waypoint along the way or else it and Grimsvotn could have joined the fracas. The subsistence of Bardarbungas caldera floor tracked quite well with Holuhran allowing Albert to reliably predict the cessation of magma at Holuhraun. Albert spotted the correlation and constructed a model and theory to the process. Personally, I think it is a rock solid (no pun) theory about how central volcanoes interact with fissure line (dead zone) eruptions. There might be some issues with chemistry of the magma at different locations along the rift, but I think it mostly fits the model.

        • It is weird that novarupta was able to erupt so far from the volcano feeding it. The distance is nothing for basaltic volcanoes but rhyolite doesnt flow the same, and it was evidently viscous with the lava dome at the vent.
          Usually rhyolite fissure eruptions or dikes are actually still vertical above a basal magma chamber, like mono inyo craters or cordon caulle, those volcanoes look like a central volcano with rifts, but are not, and are structurally very different from something like kilauea or bardarbunga where magma moves laterally mostly from one place, which is actually what novarupta seems to be. Probably way more complicated than that but still.

          I think katmai mountain also didnt collapse until well after the eruption but I might be wrong.

          • Yes something doesn’t quite add up with the Katmai-Novarupta story.
            Maybe there is ONE volcano with TWO vents?

  11. BOSEG… ← It’s an acronym… equivilant to → 😀

    Filet Gumbo…

  12. Why are the cliffs at Grimsvotn “newly exposed” after 50 years? Is this climate change or volcanic heat?

      • A lot of non-volcanic mountains are losing their glaciers. Why I asked.

          • Carl’s article mentions the weight of glaciers as one of the metrics used in calculating eruption characteristics….then at the end mentions that some of the assumed variable values in the Carl vs Albert bet may have been off a bit.

            Is this about the glaciers? Carl won’t say. He left.

  13. Hi everyone, as a long time lurker I have been dismayed by Carl’s announcement, especially as I had just decided to write my first comment. I hope he will be back, his contribution is invaluable.

    The bet on Grimsvotn made by Albert and Carl brought to my mind another prediction, on Campi Flegrei, published in a Nature article by Chiodini et al (2016) Magmas near the critical degassing pressure drive volcanic unrest towards a critical state. I read about it in the comment section a few years ago, probably many readers are familiar with it.
    We are now entering in their confidence interval for the date of eruption and the trends they had identified in CO, CO2 emissions and inflation have continued pretty much as expected, suggesting that the geothermal system is continuing to heat up and pressure is increasing. INGV also registered an increase in tiny shallow quakes, nothing suggests an eruption is imminent but I wondered if somebody with more expertise wanted to have a look at how things are progressing relative to the forecast.
    Monthly reports published by INGV contain all the variables used in the article, they are in Italian but I believe English speakers should be able to understand most of the data reported in them quite well.


    • Haven’t read it. But I’m my opinion INGV scientists are first rate, despite what any money seeking slime bags have to say. INGV always seem to be “on their game” when it comes to volcanoes.

      • The problem is that in Italy there are regulations (Agreement DPC-INGV 2012-2021) that prevent INGV from making public any data or research that is connected to a risk. INGV is obliged to transmit this data to the Civil Protection, and only after the Civil Protection will decide whether and what to make public. Therefore, if INGV were aware of worrying data, it could not speak publicly without the permission of the Civil Protection. This is the reason why in the Italian volcanology sites we don’t find any real time data of gps, or chemical etc., except seismograms.
        We can only have some monitoring data in weekly and monthly bulletins, but little data; recently thanks to the legal battles of a Neapolitan lawyer the publication on the bulletins of more data was obtained.
        It seems that in Italy the monitoring of volcanic risk is a state secret.

        • @Scienza Obsoleta
          You’re right that there is a weird secrecy about row data, probably derived from the Giuliani case before the L’Aquila earthquake (a scientist who claimed to be able to predict the earthquake using radon). But they are actually providing public assessments of current risks without passing through Protezione Civile, which I definitely woud not trust, they are a politicized body and did a huge mess before the L’Aquila earthquake, mainly because admitting the existence of an increased risk would have required doing something about all the public buildings they perfectly new to be totally unsafe in case of a large earthquake. They are also terrified of triggering false alarms and maybe evacuate thousands of people for a risk that fails to materialize, this is possibly a huge issue.
          On the other hand, I completely trust INGV, for Campanian volcanoes they only issue weekly and monthly bulletins because there is no imminent risk, if needed they woud do more. They cannot order evacuations but can inform about potential eruptions.

      • Actually some of the authors of the article are INGV scientists and the article is cited in all Campi Flegrei bulletins, that’s why I’m taking it so seriously. It is interesting as an experimental attempt to long term forecasting of a restless caldera, much like what Carl and Albert did on Grimsvitn, for short term risk assessment there are other tools.
        But as I doubt the authors or INGV will provide public follow-ups on the model, I was trying to understand how is it going.
        I’m a statistician, not a geologist, all I can say is that the parameters they used have maintained their previous trend, which implies that, if their model is correct and I have understood it correctly (big ifs), this could point to an eruption about two years from now (2019-2023 was their confidence interval).

    • I remember that article.
      There was also a really interesting article a while back about the seamount Marsili (is that the correct spelling)?

      • Perfect spelling (let’s see if I manage to put a comment exactly where I want to)

        • Marsili is quite prominent on Google Earth and very centrally located (surrounded by other volcanoes on at least three sides). Would love to know if further work has been done on that one.

          • I’m not aware of new research on Marsili, probably it is not a priority for INGV as it is too deep to cause problems in c’è of eruption and it does not seem prone to flank collapses that may produce tsunamis.
            The geological setting is fascinating, very deep earthquakes have been recorded (up to 600 Km, three years ago a M5.7 470 Km deep) as the remnants of the Tethys ocean plate are still resisting subduction.

    • It’s on the usual tectonic fault (southwest of the mountain). Not related to the volcanic system.

    • They are saying it’s a typical swarm, but if so it is a robust one! Maybe triggered by the So. Cal. quakes. Hood is about an hour east of where I sit, so if it decides to prove USGS wrong I have a nice view of the fireworks!

      • Sn hour on foot or by car?

        If it pulls a Hekla you could be in the debris field from breccia…

        • By car… so if it does pull a Hekla (the geological record shows it usually doesn’t, but “things happen”) I can bail pretty quick.

      • A swarm at Mt Hood would only be concerning if it was directly below the volcano. No notable seismicity has ever been recorded there to date.

  14. …watching with amusement the coverage of this predicted hurricane that has yet to even have closed circulation yet. Even though it in a perfect environment to form.

    In order for it to meet their projection. It’s going to have to go through a “bomb” strengthening stage. The broad midlevel low has been drifting off shore for a day or so but can’t seem to crank up into a tropical storm yet.

    • Yesterday I had a thunderstorm roll through that left me with two small dogs and a 98 lb monster shivering in my lap.

      • Our little 10lb. Maltipoo is totally impervious to thunder,lighting fireworks, etc. when my Redneck neighbor spent a good chunk of money on Fireworks on the 4th.(last year he burned down his city garbage can. ) Our little girl slept through it all with all four feet in the air.
        Although they had an Awwww. sh****!! moment when someone dropped a cigarette into the fire works pile..
        The late teen son actually extracted the cig
        with his bare hands-the pile did not go off…

      • The small dogs have been “boom shy” since before I had them. The tooth monster is afraid they will get attention and he’ll miss out.

    • I imagine the Hurricane hunters are having a blast. Duke Field is a C-130 airfield on Eglin just south of Crestview FL.

      Almost no travel time to get to the storm. Lift off and your in it.

      And if you need a part. Put down at Duke and you have the best C-130 maintenance crews in the world sitting there waiting on something to do.

      • Yep being close to maintenance is always a good thing..
        Nothing says sucks -like changing a Volkswagen sized engine in a 35 kt. Arizona sandstorm..

        • For all, he means the engine was the size of a whole Volkswagen, not just the engine of a Volkswagen.

        • Hurlbert Field is probably a very welcome stip. One of its approaches comes in off the water with the (wide) strip just North of hwy 98. Typically it’s used to play with V22 Ospreys.

      • New Orleans had put in place an effective “no wake” zone on its streets. Any thing over 5 mph in standing water is subject to a citation.

        A year or two ago, I spotted an actual “street sign” that stated “No Wake Zone” in Chipley Florida. It wasn’t an actual municipal street sign, but one placed by a nearby resident in a low spot on the road. Evidently they were tired of having the bicycle parked next to their front door being knocked over by the wake of passing cars.

    • 000
      WTNT32 KNHC 131152

      Tropical Storm Barry Intermediate Advisory Number 12A
      NWS National Hurricane Center Miami FL AL022019
      700 AM CDT Sat Jul 13 2019


      LOCATION…29.3N 91.9W

      …The estimated minimum central pressure based on surface observations
      is 991 mb (29.26 inches). An Air Force Reserve Hurricane Hunter
      aircraft is currently enroute to investigate Barry.

      • Now Hurricane Barry if this is correct.

        AL, 02, 2019071312, , BEST, 0, 293N, 919W, 65, 993, HU

      • And it is official now.


        WTNT32 KNHC 131454

        Hurricane Barry Advisory Number 13
        NWS National Hurricane Center Miami FL AL022019
        1000 AM CDT Sat Jul 13 2019


        LOCATION…29.6N 92.0W

        • Probably the most gimped out “Hurricane” I’ve ever seen. Bill the Cat would have been a more accurate name.

          • Back down to TS at the latest advisory and over land. Most of the heaviest rain still to come onshore though.

            LOCATION…29.8N 92.1W

          • Flash Flood and Tornado Warnings in Mobile

            Tornado Warning
            National Weather Service Mobile AL
            202 PM CDT Sat Jul 13 2019

            The National Weather Service in Mobile has issued a

            * Tornado Warning for…
            Monroe County in south central Alabama…
            Northwestern Escambia County in south central Alabama…
            Western Conecuh County in south central Alabama…

            * Until 300 PM CDT.

            * At 202 PM CDT, a severe thunderstorm capable of producing a tornado
            was located over I65 And AL 21, or 5 miles north of Atmore, moving
            northeast at 30 mph.

            …The National Weather Service in Mobile has issued a

            * Flash Flood Warning for…
            Mobile County in southwestern Alabama…
            Baldwin County in southwestern Alabama…
            Western Escambia County in south central Alabama…
            Northwestern Escambia County in northwestern Florida..

          • Yeah, I took a photo of one TV channels coverage of the warning and sent it in as a weather photo to a competing TV station that is blocking access to my area.

          • All three tornadic cells were Doppler Indicated with no reports of surface interaction.

            Additionally, we have been deluged with zero inches of rain here. You could see lightning over Mobile all night long.

    • Just remove the /pub from the link and it works. You can click your way there from the earthquake page. When you get to a map, click “Time series”, then “Allar stöðvar”.

  15. Slightly OT: Seattle area quake er,”quake eruption” and it is:” not connected to the California quakes.” no kidding, Kemosabe’.

    • I haven’t looked at the focal mechanism. But I have to wonder if it is related to crust flexure for the Cascadia…

    • Good heavens these people need to get some perspective!

      “So far there is no tsunami warning”!!!!!

      A tsunami warning?! From a magnitude 4.6 earthquake! The only sort of tsunami an earthquake like this could cause would be a landslide-related one and that would be so localised as to render any wider tsunami warning system pointless.

      They also show footage of the California quakes. Nicely panic-inducing and unprofessional there.

      Yes you can feel a magnitude 4.6 earthquake, but unless there are extremely freakish circumstances it will not result in anything more than very small amounts of damage.

      • Embarrassing, to say the least- acutally surprised they didn’t tie the quake to Yellowstone..

      • It could be that people are expected to flee to higher grounds when they are near the coast after a quake regardless of ther being any warnings. Becouse generally those kind of warnings are musterd after supper if you are close enough to feel the quake.

        Giving an all clear warning then would be just a signal that they can get out of hiding.

  16. There’s a star at Torfajökull

    12.07.2019 17:16:40 0.1 km 3.2 99.0 11.5 km WSW of Landmannalaugar

    • It’s in the same area as the swarms that got some attention a while ago. I don’t have my plotting tools at hand, so I can’t check if it’s actually on the same swarm or if it’s a bit to the side. Stars are not unusual at Torfajökull, but given the recent history of this particular corner it is worth keeping an eye on.

      • Looks like the same spot as the recent swarm but very shallow..

      • I agree. If this is another indication of the reactivation of the Veidivötn fissure swarm, it would be not a good sign.

    • Torfajökull Is a very old volcano
      Its often re-activated by intrusion from Bardarbunga as the basalt magmas force out the stale ryholite in Torfas chambers. Some 1477 magmas where basalt – ryholite mix the two melts where souch diffrent in viscosity like oil in water. In Torfa you can find basalt rocks with pale ryholite chunks in

    • Looks like ice melt all the way down to solid ground. A lot of energy to make those holes.

    • Did a Giggle, but it is hard to translate, for me anyway. What I caught is this (in short):

      Geothermal activity causes open water in the cauldrons all year now. Sulfur smell is noticed at the eastern cauldron. Also (bed?) rock can be seen, that has been covered by glaciers thousands of years.

      I am not sure…, were these cauldrons at the southeast rim of B? Or were they above the path of the dyke to Holuhraun?

  17. @DrChuck.

    You have two comments in the pending que {aka “The Dungeon”}. The second comment says to ignore your first. Would you like me to leave them both in pending or bin them both?

    Note:Even if your response is binned, I can still read it.

  18. Is it a aa or aaa or maybe a litium. Maybe we can save the world when we set of a volcano. Hekla only need a +4 battery

  19. Katla may be about to erupt now..👏. it has a bunsh of eq. Maybe some one have charged its battery

    • This time of year it is best to first look at the depth of quakes for that area.
      Summer is hear and the Ice cap will experience some seasonal quakes.

  20. Interesting but small little rattle under Hekla at 2.3km down. The higher sensitivity network is picking up these small quakes, and there has been a slow but steady trickle of them the last year.

  21. Katla, Hekla, Grimsvotn. Bardarbunga, Torjfakull, and Hedrueid (Maybe Askja too) are all restless. Could this be the start of a mantle plume pulse or bad luck?

    • We are already in that pulse likley
      Its been many large VEI 4 and small VEI 5 both effusive and explosive events in era 1996 to 2014

  22. I wanted to write an article on that but that would be out of my weight class If the bardarbunga eruption and grimsvotn eruption was a result of the start of the pulse and it still hasn’t peaked yet then I wonder if there could be a VEI 5+ in the future.

    • I have been waiting for years and years… i am now all out of hope. There has been speculasion on a litle eruption in katla some years ago. Can it be the 4. Something 1 1/2 year ago. Katla been more or less quiet after that

    • Funny that. Got hungry last night and noticed I was out of frozen burritos, so I made a quick etouffee. Normal shrimp.

      • Living in an old fishermens community on a small Island I am preparing for retirement within a few years with a small fishing boat, makrell rigs and some crab/lobster cages. Shrimps are out of reach with a small boat. My neighbors, a couple in their eighties are, most of the year fishing allmost all food themselves. Their recepies are uneatable for anyone else. So seafood recepies are needed.
        Back to Iceland, going there again next week, and for the first time I have rented a 4x jeep and plan to inland on the F-roads to have a closer look at Hekla, Myrdalsjokul, Askja and maybe Holohraun. Hope I will not break Lurkings “rule of thumb” – not to be there when it happens. By the way, while excellent with fish, why no crabs or lobsters in Iceland??

        • We are awaiting your post describing the adventures! Do take a camera..and let someone know where you are at all times..

        • If you want to eat lobsters in Iceland, head east to Höfn and visit Humarhöfnin restaurant. It will probably cost you a day of travel but if it’s lobster you want, then lobster you’ll get.

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