Greip Expectations

 

Part 1 of a Greip Series

This week, under the rumblings of Torfajökull, we return to one of our favourite areas within Vatnajökull that is yet to show it’s true hand. Or has it already and is there evidence to support that? Due to some recent activity, Carl has been getting increasingly excited in the back channels and put his secret volcano lair on hold. He wanted to write another article on the subject of Greip with some interesting interpretations and speculations about future possibilities. It’s been a couple of years since I wrote the original Greip article and she’s been rather busy during that time. Since then I had wanted to revisit the deadzone as well as some other article ideas but a rather long period of anxiety and depression decided to make an appearance and five months off work flew by without any constructive input into anything, let alone the VC blog. I had lost all interest in my interests, hobbies and passions. Other than my family and friends that supported me through it, the one passion that did help was music. That gave me the drive to get up and do something constructive as well as appear in front of a crowd. Well, as much of a crowd as you get with doom metal! So, this is my cathartic piece now I’m back and able to contribute. 

Carl and I decided to collaborate on this one as we wanted to do an in-depth series and make a claim on Greip and what it could become. Carl will be discussing GPS movements and musings and myself covering the earthquake activity and graphical speculations. So, without further ado…

Wind of Change

So, what’s changed since July 2017? Well, let’s take a broader look at the deadzone and Vatnajökull first.

Figure 1. Overview of the deadzone and western Vatnajökull showing all earthquakes from July 2017 to present. Plot by Andrej, data from IMO.

Things seem to have picked up in recent months with a few volcanoes showing signs of unrest. Öræfajökull has been discussed at length and excitement was growing last year that we might see some red hot volcanic action, but now it’s gone relatively quiet, save for a few scattered quakes. We’ve also been excited to see a few quakes in the deadzone, some on the same line as the 939 AD Eldgjá fissure and some on the Bárðarbunga and Grímsvötn fissure swarms. We know about the other usually noisy volcanic culprits so I won’t detail them, but what stands out here is the activity along the Grímsvötn fissure swarm; from the eastern and southern edges of the Grímsvötn caldera system, through Haabunga and onto Thordarhyrna.

We’ve discussed Grímsvötn’s climb up the cumulative plot in other posts and an eruption here could occur soon, with the right nudge and preceded by a decent earthquake swarm. But, I’m not going to speculate on that here as Albert and Carl have already done that. What I’d rather speculate on is the nature of a future eruption, which I will do so as we work our way through Andrej’s map porn.

The Deadzone

Figure 2. Cross section of the deadzone with Torfajökull to the west and the Vatnajökull systems to the east. Plot by Andrej, data IMO.

So, is there anything interesting going on? The middle deadzone is still a relatively quiet place and any quakes are in the top 10 km of crust. Whilst we’ve seen a few quakes on old fissure lines it certainly does not mean they’re about to wake up and have ‘Jesperitus’ (lots of runny lava). It could, however, point to increased tectonic strain in the area resulting in brittle fractures of upper crustal rock. As we near the peak of the rifting cycle, this strain will only increase in intensity until relieved at some point along the rift. We’ve also seen that Torfajökull has been noisy recently with a few swarms occurring near the Bárðarbunga fissures that enter it on its western margin. The recent activity along the southern tip of 1477 Veidivötn fissure occurred after this plot was made, so for those details please refer to the plots in this article. Some deep quakes can also be seen under Vatnajökull, under the Thordarhyrna and Hamarinn systems.

Grímsvötn Fissure Swarm

Now we’ll move on to Grímsvötn and friends to see what’s been going on there.

Figure 3. Cross section plot of quakes along the Grímsvötn fissure swarm and Greip area. Plot by Andrej, data IMO.

Whilst we’ve waited an age for Grímsvötn’s cumulative plot to get out of the blocks, it has recently started to pick up speed, finally. Activity around the caldera is commonly found around the southern caldera rim where the most recent eruptions have occurred. Lately, more shallow earthquakes have occurred towards the eastern caldera rim as well as some mid-deep quakes. As is Grímsvötn’s nature, deep quakes are rarer than potassium woven swimming trunks. We can postulate that the lack of deep >20 km quakes under Grímsvötn is indicative of an open conduit system or a wide area of hot ductile rock underlying the colder intrusive bodies of the upper caldera system. Melt influx from depth into the upper magma chamber(s) should be mostly silent, mostly. Expansion of the upper magma chamber(s), and the increase in earthquakes generated may be our only seismic clue to the pre-eruptive state of the volcano, we don’t get the earlier warning of deep quakes. There have been a few quakes stretching out to the NE towards Greip, but not enough to draw any serious beard stroking of a connection between the two, but more on that later.

Greip

On to the troubled sister. She’s been busy, busy enough to repeatedly catch many an eye on the blog and stir up continued interest. What stands out more than anything in the figure above is just how noisy Greip has been in just two years. That’s a lot of data points and I’d hate to imagine the global warming input from Andrej’s PC from running and analysing all this data.

Figure 4. A plot of all Greip earthquakes from 2001 to present showing frequency, depth and magnitude. Plot by Andrej, data IMO.

As you can see from the graph above, the frequency of earthquakes has been much higher in the last couple of years. If we look back further and discounting the noise from the August 2014 dyke intrusion, we see that there is a burst of activity following the end of the eruption in 2015. It appears that something changed at this point in the Greip system. The deep area between 15 – 25 km depth has been very active since Holuhraun finished erupting and is the main focus of Greip’s activity. Magnitude also appears to be on the rise but we may need another few years of data to establish any definite upward trends for this.

Figure 5. A plot of magnitude by time at Greip. Plot by Andrej, data IMO.

We’re not sure why the 2004 – 2010 time period has such high magnitude data in comparison to the rest of the data and it skews the plot somewhat. Maybe mislocation of noisy quakes from bardy and Grímsvötn were attributed to Greip due to the poor seismic network at the time. It does seem strange that all lower magnitude quakes are missing even though they were detected before this time period. Moving to more recent times, the events of 2014 can be seen as a prominent vertical line. But there’s that other ‘stack’ that appears in 2015 as bardy finally stops dropping and reinflation starts anew.

Figure 6. A plot of earthquake depth by time from 2008 to present. Plot by Andrej, data from IMO.

Here we see the same trends as the other plots in terms of activity bursts. Another noticeable feature is the separation of surface quakes from deep quakes. Maybe a possible lid on surface progress due to a more resistant crustal layer or the existence of an already present melt pathway laterally at approximately 12 km into other volcanoes in the area. Something I’ll discuss later.

Figure 7. Cross-sectional plots from the south and east showing the vertical nature of Greip. Plot by Andrej, data IMO.

Starting in the lair of Cthulhu (unofficially >20 km depth), we see many, small magnitude quakes indicating a continuous rate of influx of melt from the MOHO. How do we know they are due to magma movements? Well, thankfully lots of other scientists have studied these quakes and their low-frequency signals. Being a bass player in B standard tuning, it’s not what you hear, it’s what you physically feel as your internal organs start to liquify (think just off brown note territory). Deep, magmatic earthquakes have low-frequency profiles. There’s only hot, ductile crust down there so no high-frequency brittle fractures like you get at the surface. Some fracturing of the crust does occur during dyke and sill formation, but any high frequencies are tempered somewhat by the Queen-sized pressure. Here is a snippet from a paper on Askja discussing deep, magmatic quakes:

“There is a possibility that the lower-crustal earthquakes have a tectonic, not magmatic origin. However, the striking mid-crustal gap in seismicity from 8–12 km depth, and non-overlapping epicentral distribution between the upper-crustal (tectonic) seismicity and the lower-crustal events is evidence against this explanation.” H. Soosalu, et al. (2009)

This has been a common pattern since the end of Holuhraun, see Figure 6. above. Are we seeing increased melt influx during recent years or are we seeing a particularly noisy episode of sill storage expansion via CO2 exsolution or crystallization in situ? We’ll have to wait on that one until more evidence comes to light or we see more data patterns over time. The earthquake scattering pattern splays out towards depth as we would expect from it sitting right on the active extensional rift zone, with each side being pulled apart in opposite directions. Remember the upside down boat hull that’s often discussed? More on that later…

Moving up, the 20 – 10 km midsection is represented by a vertical column that is fairly horizontally confined. We’ve seen some greater magnitude earthquakes in this region recently, above that of the general tick. If we infer that all quakes in this area are due to sill expansion then we could imply that the growth of the plumbing system has accelerated in recent years due to higher melt influx. With the additional data from the next 2-3 years a much clearer pattern may be apparent and we could start speculating on cumulative plots like the Grímsvötn one. Estimates of the volume are possible using the denser earthquake clusters, but they are likely to have a large margin of error. I’ll leave that for others to speculate on.

The view from the east shows the cooling dyke as a separate column to the right of Greip. Can we imply a connection from the few quakes at ~15 km that seem to connect the two columns? Not from this data set, but the evidence for a connection was much stronger during the 2014 eruption and from an increased dataset and subsequent papers on the subject.

The upper 10 – 5 km section is mostly void of earthquakes, especially if we discount the dyke. As discussed in H. Soosalu, et al. a gap of seismicity between lower and upper crustal earthquakes lends weight to the deep quakes at Greip being of magmatic origin.

The upper 5 km of the crust has a reasonable scattering of earthquakes and we can infer, through the logic above, that these are of tectonic origin. We are, after all, sat on the middle of the rift. Greip also has some big neighbours, all of which offer their bulk and stress to the surrounding area. I’m not convinced of any hydrothermal activity here, I’m certainly not aware of any evidence for hydrothermal activity at this point. The cauldrons seen in the ice 2014-2015 were much further north above the dyke path and into the graben. Do correct me if I’ve missed something in Icelandic news.

Figure 8. An earthquake to area plot where the main scattering of earthquakes by depth layer has been grouped. Plot by Andrej, data by IMO.

The shape profile of each depth layer lends itself to a rather interesting situation. We see the deep earthquakes aligned with the Grímsvötn fissure swarm in the SW-NE bearing and we see the yellow midsection reaching out to Bárðarbunga and the dyke path. That’s not to say that it’s definitely on Grímsvötn’s fissure swarm; this orientation is common due to the rift angle at this point in Iceland.

Volcanic Love

Volcanoes in Iceland have a bit of a habit of stepping on each other’s toes, especially where fissure swarms overlap. Take a look at the recent unrest at Torfajökull along the historic Veidivotn fissure lineament and, after layering historic fissure eruptions on top, you can see what Bárðarbunga has done to poor Torfajökull over the years. Various intrusions have ripped this volcano apart and left it a steaming pile of beautiful rusty rhyolite hills. Holuhraun I was initially attributed to Askja, but after an investigation during Holuhraun II, this was revealed as a first jab by Bárðarbunga. Redrawing the fissure swarm areas of these volcanoes with the increased data from petrology led to a fair overlap in the lava plains beyond Vatnajökull. There’s no shortage of takers in Iceland when the rift opens and they certainly don’t abide by our lines and boundaries drawn on maps.

Bárðarbunga

Activity to the NE, Kistufell, is often suggested on the blog to be the originating point of the 2014 dyke intrusion due to its place on top of the plume head and the presence of precursor earthquakes prior to the main unrest at Bárðarbunga’s caldera. Now, after a bit of digging and nodding off whilst reading scientific papers in the early hours of the morning after being woken up by the kids, I came across a paper by Green (2015). In it, he discusses the stress changes induced by the dyke’s propagation. He discounts the precursor activity at Kistufell as the source of the intrusion and attributes it to a building stress field from magma accumulation under the caldera. During the dykes propagation to the SE and then to the NE, secondary tectonic earthquakes were generated and then dampened by the changes in the positive and negative stress field, respectively.

So, if Kistufell isn’t the source of the magma, where did it come from?

This figure above from Hudson, et al. (2017) implies a connection with Bárðarbunga using the data from the 2014 eruption. It also gives a nice hypothesis on why there was an area of aseismicity at the knee/elbow of the propagating dyke; an area of shallow melt accumulation, and therefore ductile rock, at the base of the brittle upper crust. The seismic analysis of some of the quakes within the Greip column has been interpreted as non-double-couple brittle rock fracturing within the sill complex as melt enters the system once rock fracturing has taken place. This appears to be a continuous process as earthquakes appear weekly, if not daily at times at Greip.

“There appears to be an approximately constant average rate of deep seismicity over the time period, with no obvious change associated with the eruption. An apparent lack of deep seismicity during the dyke intrusion and eruptive periods shown in Figure 2 could indicate a genuine lack of any melt movement at depth during that period, but it is more likely that the seismometer network is less sensitive due to the many earthquakes generated during the dyke intrusion and eruption”

Figure 9. A plot of earthquakes from the last two years of the Bárðarbunga and Greip area. Polt by Andrej, data from IMO

Looking at the activity from the last two years between Bárðarbunga and Greip, we see no clear signal of seismicity connecting the two. We see residual quakes from the 2014 dyke cooling and contracting. If there is an aseismic zone connecting the two we are best looking at alternative sensors to help us see what’s happening. There is evidence that melt accumulation started again following the end of the eruption in 2015 (Jónsdóttir 2017) but GPS readings don’t tie up – Carl will discuss this in his part.

Bárðarbunga is likely to have multiple feeds up from the lower reservoir, due to its mature stage in life, with some being almost aseismic. We do see deep earthquakes indicative of magma movement under the caldera with the melt constantly percolating upwards and filling the sills and magma chamber(s).

Grímsvötn

So, let’s say Greip is connected to Bárðarbunga by a noodly magmatic appendage, is there any evidence for a connection to Grímsvötn?

Figure 10. A plot of earthquakes from the last two years of the Bárðarbunga, Grímsvötn and Greip area. Polt by Andrej, data from IMO

The greater distance between Grímsvötn and Greip is the first thing that stands out in the figure above. But, that didn’t stop Gjálp back in 1996 from getting Bárðarbunga and Grímsvötn sharing bodily fluids. Was Greip involved in priming this eruption via feeding Bárðarbunga or Grímsvötn? It’s possible, but sadly the sensor network wasn’t sensitive enough to pick up the low magnitude quakes at Greip. I suppose a by proxy connection to Grímsvötn via Bárðarbunga could be implied if a little contrived.

The main eruptive activity at Grímsvötn has recently been on the southern rim of the clustered caldera complex, quakes in this area are no surprise. What is noticeable is the deeper activity in the NE area of the complex, an area that not been active for some time. Could this eastern caldera reactivate? Are we seeing increased melt influx across the broader NE area of the Grímsvötn fissure swarm and can this be linked to Greip? That’s hard to say as it could easily be tectonic in nature with the strain being released along the rift.

Figure 11. Cross-section of the Grímsvötn fissure swarm based on the boat hull magma reservoir theory championed by Carl. This differs from the gravity fed model championed by Albert. Graphic by Gaz, theory from Carl.

If we infer that Greip is the next volcano inline within the Grímsvötn fissure swarm then we could see co-eruptive behaviour during a major rifting event. We could witness dykes propagating between them through seismic activity, but more than anything else we would be in awe of watching a volcano being born in an area where data and imagery are so rich.

Offset

One thing that stands out above all is the offset of Greip from the other neighbouring volcanoes if we are to interconnect them. We grow up seeing the classic volcano illustrations in school books of a nice straight magmatic conduit rising up and leading to a perfect layered cone belching pulverised rock to the wind. In some settings this could be true, but not in Iceland where everything has been stretched and squeezed over the millennia. The fractured nature of a rift zone creates many variable paths for magma to work its way up.

We saw this offset of deep magmatic influx at El Hierro in 2011 (Domínguez Cerdeña 2013) as well as the current and historic activity at Askja where the offset is to the NE (Soosalu 2009). Also, Katla’s main deep feed can be found on the east side of the caldera imaged by recent seismicity, but it’s not as displaced as the others mentioned above.

So, it’s completely possible for Greip to be a melt feeder, especially for Bárðarbunga, but could it be more in the future?

Future World

So what does all this evidence mean for the future? Well, for a start we desperately need some more sensors in the area, the more data we have the better supported our hypotheses are. Are we finally seeing the magmatic appendages of the Illuminati of the volcano world and its influence on the volcanic powerhouses of Vatnajökull? Is this a sign of the top of the mantle plume head nearing its peak and the main source of magma for the plume volcanoes? Or are we seeing a formative volcano in the making that reached out and had the power to slap Bárðarbunga 90° and may be about to steal its magma as well as its thunder? On to Carl for more ruminant ruminations on that subject.

Beardy Gaz

Sources

Domínguez Cerdeña, et al. (2013) – Seismicity Patterns Prior to the 2011 El Hierro Eruption

Green, et. al. (2015) – Triggered earthquakes suppressed by an evolving stress shadow from a propagating dyke

Jónsdóttir, et al., (2017) – Bárðarbunga volcano – post-eruption trends following the Holuhraun eruption in 2014-2015

Hudson, et al. (2017) – Deep crustal melt plumbing of Bárðarbunga volcano, Iceland

Soosalu, et al. (2009) – Lower-crustal earthquakes caused by magma movement
beneath Askja volcano on the north Iceland rift

271 thoughts on “Greip Expectations

    • Mental health is something we should all talk about more, it should never be a taboo subject. It’s been hard, very hard but I’m getting there.

  1. What an amazing article you guys made!
    Excellent geological data!

    22 April 2019 http://hraun.vedur.is/ja/vatnajokulsvoktun/grf_uppsafn.html
    Here is my update on Grimsvötns cumulative seismicity. Earthquake activity have become a bit more frequent since 2017 but its still not the even rising climb that it was after 2004 s event. The Earthquakes are caused by the magma body expanding and pressning on brittle bedrock walls.
    The volcano is refilling but it still seems to be Re – covering from the huge 2011 event. There been numerous strong swarms thats increased pressure alot and in 2018 the volcano seems to be started a slow steady climb knowing it haves the highest magma supply in Iceland. Still it can be rather tricky we may never know how the plot will behave.
    This is a good way to learn just how much Grimsvötn can recover after a large volcanic event
    And it seems its refilling pretty well after 2011 s event. Knowing the diffrence between magmatic quakes and tectonic ones can be a bit tricky.
    Grimsvötn arera is open conduited and experience little quakes overall only major rifting or as this case increased magma pressure in the upper magma chamber. GPS on ground says Grimsvötn arera have inflated almost 50 cm since 2011 and thats another sign of magma Re-charge.
    The next eruption is impossible to predict for the moment as the plot needs to behave in a more straightforeward manner I think ( steady increased climb like the 2 events before ).
    It will likley take longer for it then between 2004 and 2011 knowing 2011 was a rather large event.
    But Grimsvötn seems to be recovering from last event.

    • To be honest I think Grimsvötn is taking a semi – nap half sleep after 2011 s huge 1km3 event
      It have refilled a bit.. But its not the steep climb that it was in 2004 and before 2011 in this plot.
      This is very useful information and gives clues to magma supply and just how fast this volcano can recover after major eruptions.
      It have recovered a good bit… but its not the steep climb… thats needed for eruption

  2. i try to teach all my grandkids that everybody has crap… the modern world paints it’s self with happy colors on the internet, but that’s not the truth. The world has a full spectrum of colors and some of it is black. The brain is a part of the body and subject to body problems… broken bones, malnutition, poisons, fatigue, and just cells that don’t work well. We think the brain is the person so when one’s brain isn’t working well we feel like failures and experience shame. But that is not right. Would we blame the leg for getting broke? Would we expect the leg to still fulfill the duties of being a leg if broken? Would we expect the leg to figure it out, work through it, or just get on with standing up as our families and friends need us to stand up? Depression is a disease of the brain and it’s not fair to expect the brain to still function when sick. The leg needs healing, it cannot heal it’s self and the brain even more so. i wish we could see the brain as only a part of the person and sometimes in need of help and attach the amount of care and concern with a broken brain like we do with a broken leg……. and use those crutches! They are there to support You while You heal. All the Best! and as my 90 year old friend says….. Glad You are still on the planet! Something really exciting might happen tomorrow and You wouldn’t want to miss it. All the Best!motsfo

    • Trust the little old ladies for advice! They have seen it all. It is for a reason that they are still on this planet. And yes, recovery from mental health issues is agonizingly slow with false dawns and setbacks, but you do get over it. It is so difficult because it cuts to the heart of who we are. I was at a concert recently where the lead singer started to talk about mental illness being a stigma. I never heard the audience being so quiet (before the applause). It makes you realize how common it is, and how many people feel they need to keep theirs hidden.

      But back to the volcano: is it near the saddle point of the rift?

        • Can’t tell you – I am not a little old lady. Walls have been tried but lava tends to go over it.

      • Hard to pin down in this area using quakes on their own, when Carl discusses GPS movements it may shed some light on it. I wouldn’t be surprised if it was the new triple junction point.

    • Amen to that. My wife, kids, and I all have some sort of depression or the other, so I know how it is. With everything going on in this world I think most folks have some sort of anxiety going on.

      • Beardy Gaz, I forgot to congratulate you for this amazing post and article. Very exciting stuff.

        And my best wishes for you personally. I know how it feels depression, I have had myself often and it’s good for people to talk about it and support each other, or sometimes just speaking out!

        I keep discovering every month new tips to keep my life and my moods better. Simple stuff like being a lot outdoors, doing things we like, getting enough sleep and good food, getting social time, and of course talking about volcanoes 🙂

        • I know about it too. I wasn’t far from doing stupid things at one point a few years ago (I had it rough in school to say the least) and I promised myself never to let it get that bad again. Sometimes it seems impossible (especially when I had major spinal surgery this January- very successful thankfully) but god damn it is worth the battle. It is always eye-opening to see/hear how many people go through things like this. Volcanic therapy for the win- apart from the sulphur!

  3. I have updated my Grimsvotn plots, adding data since the previous posts on this https://www.volcanocafe.org/living-dangerously-another-grimsvotn-prediction/ and https://www.volcanocafe.org/living-dangerously-grimsvotn-forecasted/

    The new plots are below. The predictions are exactly the same as in the old posts, so you can see whether the new data follows the predictions.

    Red is old, blue is new data. The two plots show two different fits. The one on the left assumes that the slow start in 2011 and the halt in2015 were fully recovered by the subsequent earthquakes, i.e. the fit ignored these. The one on the right assumes that the slow start was because of the 2011 eruption came too early and that the build up to the new eruption started only later. The equations are described in the post: they are standard for failure modes.

    The new data fits perfectly on the left plot, so well that the data is hard to see. I am beginning to be a bit more confident about this. Failure happened the previous times when the number on the vertical axis reached 3 or 4. That indicates an eruption in early 2021.

    I will now go in hiding because (1) Jesper will say the plot isn’t big enough; (2) Carl will say he has scheduled a big earthquake which will trigger an eruption by June; (3) Turtle will say that Hawai’i is bigger.

    • straightforward or not, if it’s a good fit to the “modeled data” then it’s a good model. (BTW, a “model” in this context means a mathematically fitted formula that tracks with the empirical data.) When new empirical data fits what the previous model predicted, then that adds strength to the validity of the model.

      Where this process goes sideways is when the data is adjusted to fit the model. In that case, the model isn’t worth the ^@#$ it’s made out of.

      If it’s not “straightforward”, then you need to define what that means. Hard to see? Generally that is a function of eyesight and the screen size you are using. That is not the model’s responsibility. You could use a few of he correlation coefficients to measure how well it fits, but that is actually a bit deeper information than we really need in this context. Albert noted the issues with the two plots and which one seemed to have the best fit. Many of us don’t have the experience or knowledge to know what “goodness of fit” numbers mean anyway. The media tends to use our lack of knowledge to boast about how certain some pet topic of theirs is, even though it actually means very little.

      And back on the “volcano” aspect of it. Even if you had a model with a correlation coefficient of 1.0, you know good and well that a volcano is not going to follow it. In my opinion they hate stats and schedules. A statistical measure of any volcano is only going to be valid over the long term… such as “geological time” long. Get down into the short term (human scale) aspect of it, and it all goes to @#$% in a hand-basket. Albert even noted that a large quake could easily throw the models prediction way off.

      And if you remember, even IMO’s discussions about Holuhraun noted that it acted in response to a regional stress field change. Grímsvötn and the Dead Zone are on the southern side of that same MAR centered event. We may see weird stuff happening there if that stress field change happens to manifest itself down there. Torfajökull’s recent activity could even be related to it. Not meaning to be a wet noodle, but IMO is in the best position to see that if it’s coming. They have access to the high end technical data that we don’t have.

  4. Thanks for a fascinating article, Beardy Gaz. Glad you recovered from your depression. It’s a bummer, as a dysthymia sufferer myself can truly acknowledge. Onwards and upwards! (And ditto with the magma, too…)

  5. Wow. What a great read. Can’t wait for the next instalment. You guys are putting some serious work in here, so thanks for your endeavours. It’s much appreciated that I, a layman who’s been interested in volcanoes since childhood, can read such interesting articles without my brain exploding.
    Beardy Gaz, having been through depression myself I know you can, and will, get through it. Your loved ones are there to help, and you’re doing the right thing by getting it out in the open. And Death Metal is always a tonic! The very best of luck, sir.

    With thanks.

  6. Prestations, work, a job generally is seen as an important issue in life. That important, if you don’t succeed in participating in, most of people think you don’t fit. Most of people cannot make up their own minds. Repeating statements others tell them…
    This morning I read someone shot a stork from its nest last night near where I live. Since this bird does fine again (after a long period when the extinct was near), a rumour has developed they eat all (yes all) hares. Bad stork. Shoot it. Sigh. How to understand a human brain. Most of us can’t understand/oversee the complexity of matters; just a characteristic of our species. 😐

    Trying to understand/oversee volcanism in Iceland… 😉 Enjoyed your article very much Beardy and Carl. Thanks a lot! Lookin forward to the follow up!

    To topic. Looking at the graphs I see that the 2015 stack is proceeding slowly upwards and declining in Magnitude at the same time (blue and red lines). Just an observation, dunno what to think of it. In 2017 there was a slight uptick in the Holuhraun dyke activity that matches with Greip who gives it a go too (orange line). I have been wondering, but logical ofcourse: Greip likely has been included in the graph Bardarbunga 2015 –

    What makes me ask: could you provide a map of what area exactly Greips data are taken from?

    • But not convinced about Greip included in the last graph above. The part “focal depth” shows far less data than included in Andrej Flis’s… If not the dyke is showing an uptick at the same time Greip really is activating (March 2017).

    • I’ll try dig out a graphic, it’s probably been tweaked since then but take a look at the ones in my first Greip article from 2017.

      • And I who lived under the impression that storks was wading birds that only ate fish and frogs.
        Beautiful birds anyways.
        Now returning to my current tv craze, watching Alaska State Troopers on Youtube. Every time they are driving around in visible range of Cleveland I ponder if they are driving past your house.

        • of all the live dramas “Alaska State Troopers” are actually telling the truth. Spot on.

    • Hey Rob, glad you are interested in the data.

      I made a graphic showing the area boxes of the data used by me and IMO. Its pretty self-explanatory. Basically the green box is the area that is used for the plot you have showed. Yellow box is what they use for the caldera plot, which is on the same page as the plot you have linked. I assume that is the same area that is being used for caldera part of your plot above.

      And red is of course the area I used for the Greip time plot.

  7. I have a question, given that the dike from holuhraun seems to come from greip, and there is a mentioned connection that might exist between greip and bardarbunga, is it possible the dike that fed holuhraun came from greip and that the deflation seen at bardarbunga was just because that was the spot with the highest magma stand?

    Through all my knowledge on kilauea there is one think I have been consistently trying to put forward and that is that the east rift doesnt connect directly to the shallow system feeding halemaumau but instead connects at a deeper level from the base of the volcano up to maybe 3 km deep and only approaches the surface again near mauna ulu. This ‘bend’ is similar to the shape proposed for the holuhraun dike, and in both cases the magma has to move in a direction that is against the zone of lowest resistance to reach the end point. Last year during the deflation associated with the magma moving to the LERZ the summit markedly deflated and so did the east rift between mauna ulu and heiheiahulu, most significantly at pu’u o’o, but the part between mauna ulu and the caldera pit showed very little change and only stsrted deflating when literally all of the area surrounding the caldera was doing the same anyway. This shows there is no active shallow magma here, and that while there was a continuous hydraulic connection between halemaumau and the east rift it wasnt as simple as a lot of models show and certainly not a shallow tube, the old USGS map showing the rifts being molten cored is much closer. The same thing seems to happen at bardarbunga, the quakes showing the 2014 dike are obvious but do not actually form a line all the way to bardarbunga itself, rather starting at or near greip and with a seismic quiet zone between them. This zone could be a magma body which is common to both, and as said before regarding kilauea the only thing necessary to show the observations is a hydraulic connection between holuhraun and bardarbunga, it doesnt require the magma erupting at holuhraun to actually come from underneath bardarbungas caldera.

    • The initial rumble started at Bardarbunga. First 5 days of the action.
      If Greip was involved, as source, there should have been a some quake readings there I guess.

      Graph by IMO.

      • WOW so large these calderas are!
        Bardarbungas caldera is freaking more than 10 kilometers across and 700 meters deep
        That fits well for the drained volume of the 30km3 Thjorsahraun flood lava event.

        If Greip really is a magma chamber… then a chamber draining event or summit eruption coud form a New caldera Greips first caldera.
        Souch an event woud be very large with good over 10km3

      • In one of the papers I sourced they discussed the lack of quakes at Greip during the dyke progression. The sensor network was saturated with earthquakes so many lower magnitude quakes at Greip would not have been manually checked.

      • Thank you for dragging out that one. If you happen to find the same for the period leading up to the dyke propagation it would be swell.

          • Maybe the supply rate is matched by the rate of spreading, so it only erupts when a big amount of magma moves in or the roof of the chamber breaks from being stretched too far. If they coincide then that could be 1783. I guess this means grimsvotn has technically got a very high total supply but actually a very low ‘true’ supply rate, otherwise I’m sure it would be erupting as a lava shield like kilauea or basically any other basalt volcano with that sort of magma source would be. Maybe when the glacier melts shields will start forming in the area, bardarbunga has shields north of it, maybe greip will start as a shield, while the area southwest of grimsvotn is more prone to rifting fissures like 1783. If greip does erupt as a long term effusive eruption like an icy version of pu’u o’o that would surely be a tourist attraction, especially if there is no major water around it to make things more lively. Or maybe greip will come into the world as a flood basalt, who knows 🙂

          • The supply rate is roughly 0.13km3 per year that goes into the spread, and about 0.36km3 in total, or equivalent to all of Hawaii.
            The reason that you do not get a lot of big ones is that the crust is to thin to withstand high pressures, but stable enough to not putter on (and that would be quenched by water and ice anyway).

            Greip would definitely not be a tourist eruption. 1km of Ice would sort it into the ashy as heck bin of eruptions 🙂

          • And “tourist eruption” is a bit of a misnomer. Even the nice fountaining ones tend to be to large and unwieldy to allow tourists in.
            Krafla had a couple, but to remotely. The only real one I can come up with would be Fimmvörduhals 2010.

          • I was more meaning that greip might not erupt until most of the ice is gone, then become a shield with a similar lifecycle and eruption progression to puu oo, except longer lasting and probably bigger. Grimsvotn is prone to rifting but north of there is more shields like trolladynjya and all the shields around askja. Greip is maybe in an area that would do shields or tuyas like herdubreid.

            Also I would maybe not put grimsvotns supply as the total to fill the rift that feeds the area, only the amount to cause the observed inflation because that is actually the difference, the rift will fill anyway but the inflation is added extra magma that can erupt. Hawaii eruption rate average is about 2/3 of the magma erupts and 1/3 stays in the rift zones and becomes olivine crystal mush, while in iceland maybe 1/10 of the magma erupts and probably less so even with higher rates at depth the amount of lava erupted is smaller.
            Much more lava has erupted in hawaii since 1790 than in iceland. I chose 1790 because it removes the massive outlier that is the skaftar fires, that is far from a normal eruption.

            Holuhraun dike and 2015 caldera is also much bigger volume than 2018 dike and caldera on kilauea, >3 km3 vs 0.1 km3,despite similar eruptions so it shows the difference well here too.

          • Ah, I see where you are going Turtle.
            That depends on the time frame, pesky time, somebody should take to volcanoes about getting decent clocks. 🙂

            In general there should be more frequent and larger eruptions in the not so distant future as the ice-deloading starts to go full swing. But, at the time that Greíp is poking up I hope I am not around.
            Best guesstimate now seems to be between 100 and 1000 years before the glacier is completely gone.

            Then it will be “tourist eruptions”, well, that is if there are any humans around to tourist about. We are after all working extremely hard at extincting ourselves.

            I will though return more in depth to Greíp in the next article, so I am keeping this a bit sweeping.

          • Ref Carl’s note about Fimmvörduhals 2010; I used to sit and watch the video of this one back where I used to work while in between bench work. (allegedly croaked PCs brought in that occasionally contained herds of cockroaches. Which is another startling story. I had never seen Ironwolf hop around the shop like that until they came streaming out, we closed it up and tossed it in a garbage bag and liberally applied insecticide in the bag outside.)

            Anyway…. Fimmvörduhals 2010 eventually sputtered down to what appeared to me to be a single blow-torch like emision from the remaining vent. Then a quick succession of relatively shallow quakes shot across to the Eyjafjallajökull upper chamber and everything went sideways fast. Shortly after that, the floor of the upper chamber “failed” and the conduit to the lower feed system opened up all the way to the moho.

            In my plots of the time, the quake stack to the moho seemed to have a sort of embedded helical shape, but nothing really certain. Just an oddity.

          • Regarding the glacier melting though the bit in the valleys between volcanoes will probably melt first, probably quite fast if a big jokullhlaup goes through the north part or south of grimsvotn again. The last bit of the glacier might be on oraefajokull, or the mountains north of it, that might last a thousand years because eruptions are not likely anywhere in that area except oraefajokulls caldera, but the part at grimsvotn and over the dead zone is probably not going to last more than a few decades from now if said volcano really does something. Skaftar fires didnt do much to vatnajokull because it was a pretty normal hawaiian eruption by that point but another eruption of the scale of the 1783 opening stage but closer to the central volcanoes could make a reall mess of the glacier, like gjalp but 20 times bigger and 10 times longer… At the rate of melting something like that would leave a permanent impact.

            If greip has something to do with holuhraun and bardarbunga like the way I proposed too then the holuhraun dike could erupt again, not where it did in 2014 but further up under the ice, and eventually there will be a point where the amount of ice around will not be able to replace it so the glacier retreats to the mountains and greip valley can start getting serious.

      • If Greip eruptions last very long
        An island grows out the meltwater lake and lava flows out. Forming a tuya formation

        • I don’t think you have enough ice for that. Much of it will be blown to smithereens when it starts.

          The conditions for a Tuya will only last a few minutes at most. (if not seconds)

          • That will happen after a while when a cone forms in the meltwater lake
            Its very much a subglacial version of surtsey.
            When the cone grown large enough in the meltwater lake lava flows out and it becomes effusive

  8. Gaz, swell article. Talk about a monster to follow. Thankfully I have a few ties ins for the conclusion.

    In regards of my wedge theory and Alberts gravity theory, I think I should clarify that I firmly believe that both theories are correct, and that both play a part. I am as always afraid of a single simple solution to any real world problem. Part of it is gravity, part is buoyancy driven eruptions from fissure swarm wedges. Hunting for a single way to look at a volcano would only leave one standing there as a one-legged donkey at Ascot, wearing a silly hat, and be named Rees-Mogg.

    I think that Albert fervently agrees on this.

    • Cheers Carl.

      I think I should try doing a graphic that incorporates both the gravity and wedge theories. Another article in the making for the future…

      • I think that would leave you trying to whack in 4-dimensional partial path integers into your poor computer. You might end up with a Riemann rug in your Minkowski-room. 🙂

        Edit: That is probably how my brain meandered off the beaten path of reality as normally understood in physics. Strike the probably part, it is exactly how that happened. I am though happy with the fringes and tufts on my personal Riemann rug.

      • It is likely, but not assured in any way.
        There are oodles of things we do not know about Bardárbunga.

        • Isn’t it true that the location of the source vents for the Thorsjahraun flow is unknown? If this is true, this sounds a bit odd to me, unless the source vents are deeply buried under the Vatnajokull Glacier, or younger flows. For such a huge eruption of lava, there should be large rows of spatter/cinder cones and stuff, but… I don’t know how old Thorsjahraun is, but it’s likely very early Holocene.
          Not a whole lot of info on this flow I can find out on the Internet!

          • We do have a fairly good inclination at which row was the culprit.
            But, proving it is not as easy as just stating that this row is the culprit since there are oodles of rows in the area laying next to each other.
            You kind of have to go out there in person to understand what I am talking about. It is not so clear cut out there…

            Edited for clarity.

      • Here is some more Jesperitus for you to ponder:

        If you make a 3D plot of all quakes under Vatnajökull since dawn of time (which for publicly listed quakes in Iceland would be 1995), then the combination of quake stacks under Hamarinn, Grímsvötn, Háabunga, Thordarhyrna, Geirvörtur and Hágöngur makes up a cylinder shape that looks like the ring fault of a caldera that would be some 20km in diameter. Imagine if this really was the home of a large magma chamber and the listed volcanoes are just features along its rim…

        I’ll go hide under a blanket now.

        • Ding!
          You just won a free ice cream machine. You can go and shoplift it at the Åhléns of your choice.
          This is pretty much how it works with the deep magma reservoir. But the central volcanoes have discrete upper chambers of their own.
          This means that the replenishment during eruptions is quite high, and that they can erupt more than they technically are supposed to be able to on their own.

        • That’s the hotspot plume… 🙂 ahahah!
          She says: “Surprise surprise! You found me!”

  9. Over in the Mongolian town of Ulgii a very ancient conundrum might be about to be solved.

    As drunken hoards of tourists complain about being quarantined by something as mundane as two people dying of bubonic plague the real news might be that we perhaps finally have found the true host animals.

    The two victims had eaten the kidneys of the local variant of the Tarbagan marmot. While the rat has always been blamed for the bubonic plague we have always known that it is not the natural host animal since they also die from the disease. A true carrier host animal will at best just become sick from it, but most likely not even that since the bacteria and the animal have adapted to each other over a long time. Just look at the African fruit bat and Ebola.

    In some animals the bacteria can even work as a population control, if the animal grows in numbers to much the bacteria kicks in and starts to kill them due to something called population stress, this is common among voles who are regularly knocked down by hanta-virus, giardia, cryptosporidium, leptospirosis and tuberculosis.
    During normal years they are happy and not dying off in large numbers, but during vole-years the diseases that they are host animals for start to whack a mole in alarming rates. And they only cause epidemics during those years.

    Same thing might be true for the marmots and that might explain the irregular pattern of bubonic plague outbreaks.

    Mongolian authorities are treating the tourists with large doses of alcohol for their cellphone withdrawal symptom (not really true, but it goes with the homo stultus meme).

      • Not to mention that swedish microbiology is already at insane levels of sophistication… the attempt would likely be mitigated before you were caught.

        • And not to mention the level of sophistication on key word searches on the internet to find comments like that… I would guess that Jesper just ended up on a watch list.
          And that all of his trash for the next year will be checked for traces. 😉

    • Okay… “Yuck.”

      …”The tarbagan marmot has been eaten for centuries in the native cuisine of Mongolia, and in particular in a local dish called boodog. The meat is cooked by inserting hot stones, preheated in a fire, into the abdominal cavity of a deboned marmot. The skin is then tied up to make a bag within which the meat cooks.”

  10. Greips of Wrath next ? Young volcano setting out from the ash(dust) bowl – for the artic circle in search of magma, making land and a brighter future?

  11. Very nice article Gaz, thanks a lot!

    Here is what those deep swarms at Greip look like on the drumplots (image credits IMO):

    I circled the waveforms that are visible on both DJK and DYN stations and where the delay between the signals is consistent with quakes at Greip. Note that out of these waveforms, there are currently only two quakes listed by IMO. Sometimes these quake trains pass completely unnoticed by the system and sometimes they result in an entire cluster of quakes in the list. Could be that they are too small, or that you can’t separate individual events out of the almost continuous waveform. Carl might be able to tell.

    • It also has a bit to do with what IMO is putting effort into, spending hours on hard to define weird quakes out in nowhere, or immediately fix a few at Katla and Hekla. They always correctly opt for the latter.
      To determine weak earthquakes at depth without distinct and clean initial breaks is a headache.
      So, you are pretty much correct on all accounts. I just wanted to add that there is also a priority list for the IMO.

      • Fair point. Speaking of weird quakes in the middle of nowhere, there’s currently quite a lot of popcorn activity at the KIS station. It’s been going on for at least a few days and my impression is that they are getting more frequent. Now, this could simply be expectation bias from my part, but the popcorn at KIS always seem to appear when Bárdarbunga is getting closer to one of its larger quakes.

      • Ref IMO. Remember that their primary job is to protect life. It is safe to assume that efforts toward that end would be their primary focus.

    • The cone of Yasur is made of basaltic andesite, it is not the first time though that a lava lake has been reported at Yasur, as many as 5 simultaneously active lava lakes/strombolian vents (they are usually halfway in between) have been observed here. What is impressive is that dating of carbon at the base of the recent tephra sequence indicates that this activity may have been continuous for the last 800 years, and it has been reported to be erupting since it was first seen in 1774

      • It is one of the volcanoes that have had the longest known continuous eruption. Stromboli for instance has only been erupting since 1934, and Gagxanul (Santa Maria) since 1922.
        Who would’ve thunk that Gagxanul have erupted for a longer time than Stromboli. 🙂

        So, Yasur is probably the longest running eruption that we know of. But, I might have missed a volcano or two that are even more stubborn.

          • Gagxanul is the correct name of the volcano. I try to use the correct names on the Guatemalan volcanoes. It is kind of a point of pride for me. Problem is just that I am both confused and befuddled, so I do not remember the correct names for Fuego and Agua when I need to remember it.

          • It was noted in a recent Youtube video of a PBS program that the local populace have placed and emphasis on relearning their pre-conquistidor past.

            And a political aspect of the whole ordeal that really applies to everyone in general. “Those who cannot remember the past are condemned to repeat it” — George Santayana

            And in regards to the Kʼicheʼ people, it is something that was forced upon them and not a lackadaisical attitude on their part.

          • {snicker} I like that. “Chi Q’aq’ (Kaqchikel for “where the fire is”)” (Fuego) and Agua is “Hunahpú” in Mayan according to Wikipedia.
            (i.e. “Your mileage may vary” or “Objects in mirror may be closer than they appear“)

            Fuego – Wikimedia – Paul Newton, Smithsonian Institution


            OT, one thing that I find cool about it all, is the idea that many of the religious processions and celebrations are essentially just carry-overs from ancient traditions with a veneer of Catholicism painted over them. Sort of like our idea of Yule Tide.

          • I don’t think that is unique to christian festivals. Halloween is based on a time when we had 8 seasons in a year, and it was the start of the last one, the beginning of the dark weeks. (It should be about 10 days later than the US has it – there has been some date confusion.) Easter is based on an ancient festival at the start of the Jewish year (before they moved their year to begin in the autumn). (Full moon, of course, is the best time to have a party as you have light during the night. A feast during new moon (without artificial light) is not going to work well.) I expect that that too has an even older origin. Go back, and you will find that most of our ‘natural’ events were obviously the best time to party in the distant past as well. Even independent cultures would have settled on more or less the same dates, just with different rituals. I do find it rather funny when people want to ban (rename) christmas while being happy with halloween – just because halloween is a different religion.

          • I did a bit of data digging in UN data for birth rates by month. Backing out a 9 month gestation, there are peak conception rate spikes at easter/start of barbecue season and at October/harvest festival season in many countries. A stereotypical Scandinavian location, the Aland islands, show their peak at midsomerfest

        • The area around Yasur has also inflated 20 m during the past century. Yasur doesn’t have a large lava output so while it is actively degassing it doesn’t seem to be reducing pressure much.

          • Vanuatu has a tendency to do explosive, basalt, andesite or dacite it seems to rather blow up. I don’t know if this has to do with the volcanoes not rising much above sea level and the calderas sometimes hosting lakes of water. The calderas of Gaua and Ambrym have formed through maybe the largest Holocene basaltic plinian eruptions, large VEI6 or VEI7. Ambrym had an initial dacite phase but the bulk of the eruption was basalt.

            Ambrym and Yasur have similar summit activity consisting of lava lakes that shift to strombolian or vulcanian activity but Ambrym has a much bigger summit vent complex and a rift zone running WNW-ESE

  12. You know me…. OT trying something here: Ed Douglas
    @edwardjdouglas
    The legendary
    @AstroMCollins
    joined twitter & doesn’t even have 4K followers yet??

    He was up there with Buzz & Neil on Apollo 11, & at one point was the furthest any human has ever been from another human!

    Let’s never let him be that lonely again & get him some more followers

    so if You need another follow on twitter ….
    Best!motsfo

  13. In the Volcanic Love section
    “Holuhraun I was initially attributed to ” spelling mistake/typo?

    Depression is a bitch, I’m myself recovering from a severe assault from back in 2012 with related injures and such, there have been some depressed periods. Talking and being open about it is always good, hope you’ve seen the last of it.

    Great article as well! Looking forward to the following installments.

  14. OT.

    Just hot my packet of Carolina Reaper pods. Curious about all the hype. I ate a pod. They ARE as hot as claimed… but in my opinion, are not all that different than a standard Habanero, just a bit sharper in sensation. To me, this means that all the panic you see in the Reaper challenge videos is just the reaction of people unaccustomed to real heat.

    Caceat: I mess around with Habaneros quite a bit so I may have a higher tolerance than most.

    Now if I can get these buggers to root I’ll be a happy camper. It’s gonna be a whole season before my “ghost peppers” put on fruit. With success. They will both “put on” about the same time later this year.

    • Not an expert, but just put my habs in. Have grown Reapers and Trinidad Scorpions over the last couple years. Full disclosure, for ornamentals and conversation value (not habs, use those. The other two). As in Jalapenos and other peppers, heat level can vary. My reapers a couple years ago blew my habs away. I think I may have mentioned it before on another pepper discussion, but I’m a bad parent. Got one of my sons to bite a reaper (cost me $20). 🙂

      • $20 well spent in my opinion.

        I gave my grandson one of my two packets and advised him of my first hand impressions. He know what I can come up with and has had my hottest before. He is taking his pods to work for his coworkers, a group of welders and fabricators. It’s an almost certainly they will try them just from the testosterone aspect of it. Snipe/engineering types will almost never back down from a personal challenge. ☣😄

      • And thank you for reminding me of the Scorpions. I just ordered a few of the other screaming monsters to see how my crop turns out. Here is my manifest:

        Trinidad Moruga Scorpion, Pot Douglah, Datil, Scotch Bonnet

        The Datil are in the mix because I got blindsided by a Datil sauce a couple of years ago. They are not even supposed to be in the rankings of the Habanero strains, but they kicked my butt and formed the basis of my “if you can’t taste the food” belief. That sauce ruined a perfectly good Philly Cheese Steak I had bought. What I wound up with after putting the Datil sauce on there, was akin to eating a loaf of bread with hot-sauce and some sort of chewy meat of unknown origin. That shop uses Boars Head as a vendor, so I know it was good meat. I just couldn’t taste it. (Yeah, this is sort of an endorcement of Boars Head, I’ll give you that. But I’m not paid to say it and I am not with the mob.)

        Note, most of the cheese steak shops I saw in Philly during a yard period used Boars Head as a provider. All were quite excellent, except for one shop near the ex-Philadelphia Naval Shipyard.

        • That reminds me of a prank that I heard while in the yards there. Someone conned the quarterdeck to pass the word over the general announcing circuit (1MC) the following: “Metro Machine worker Rocco Siffredi, contact the Quarterdeck” Many of us about choked when we heard that. It is quite unlikely that they had a worker by that name. (Siffredi has other employment than working for Metro Machine) The difficult part about it was explaining to our female crew-mates why we were laughing our asses off.

        • I lived in the Philly area for a while after high school (my parents moved up there). Actually, west of Philly (Downingtown) but got into Philly regularly for Phillies games, take friends around, etc. Good cheese steaks. Was never down by the Naval Yard (but never had a reason to be). Boars Head is good meat, and also personal opinion. Of course, we were close enough that we could go to Lebanon, PA and get real, local Lebanon Bologna.

    • Can you imagine the salsa made from the combination of the reaper and the ghost? Where’s the fire extinguisher?!

      • I’ve done my own Pico de Gallo before. But it was more trouble than it was worth. I intentionally toned it down because of my “if you can’t taste it” mantra, but with just the fresh jalapeños and onions it was a scalp ripper. So I can imagine what sort of terror that would be.

        Side note: A stocking clerk (archaic “stockboy”) pissed me off when directing me to the tomatillos. (Not where he claimed, just Vidalea onions).

        Note 2: Vidalea onions are sweet, mild onions that by regulation around here HAVE to be from Georgia to qualify for that nomenclature. Something I don’t understand because it requires an ultra low sulfur content in the soil for the best Vidalias…. and Georgia is one of the regions that was affected by the CAMP. There are dike swarms all along the South Georgia Rift that eventually came to a stop as the Atlantic opened up. I have no idea where the sulfur went. (South Georgia rift stretches from here up into S Carolina.) I was going to go looking for dikes last Christmas but wound up not taking that trip.

  15. Thank you very much for the insight into Greip.

    It almost sounds like a scientific criminal story, with the main suspect hidden below the ice, slowly preparing her crime. So focused and concentrated that she even ignores the knocking on the door by her allies, the Bardarbunga dyke creepers. 😉 But agents Beardy Graz, Andrej Fils and Carl found her secret hideout and are dissecting it piece by piece. 🙂

    From a more scientific viewpoint, the article is yet another example how complex the situation under Vatnajökull really is. Although Bardarbunga and Grimsvötn are situated on their own fissure swarms, there’s much more interaction than just the common deep magma source. Esjufjöll and Kverkfjöll are still mysterious volcanoes to me, though. Why doesn’t the latter erupt more often? Are Grimsvötn and Bardarbunga stealing away the magma because of their rather open conduits?

  16. The prediction for the Atlantic hurricane season are for a normal year. That will be a bit of a relief after the last two years.

    • Not that pleased with a “normal” prognostication. We’ve had a dearth of tropical systems and “normal” would be bad.

      • Well with El Nino cooking things tend to slow down tropically. We’ve had a
        really wet spring here in NE Oregon . Lots of growth-and it is now warming up and drying out..do not like that trend.

        • I live in SW Washington, and with the temps getting up into the 90s we are getting worried about the fire season starting early…

        • I have a pile of yard trimmings that got too large for me to outright burn safely, so I purchased an old 55 gallon steel drum. So far I am about ¾ of the way through my two year pile of rubbish. Conditions here are perfect for it. Every thing is pretty much saturated from our periodic heavy rains, but the trimmings are still mostly dry and easy to kindle. A side effect of the rain, everything is GREEN!!! But it stays muggy. Local forest service is probably quite happy right now.

          The only place that I have seen with this much green is County Cork in Ireland. Now I can understand why Irish immigrants liked the deep South. Looking across the landscape there was not all that different that looking across a pasture in Mississippi. Other than the brush growth along the fences not having stone walls inside of them. Barb-wire, yes, even electric at times. (Makes holding the wires apart for your cousin to cross a bit crazy. If you get hit, you let go of the barbwire and he catches it in the back and the crotch. While you are jumping around from the zap, he is cussing your existence. “Trickle Chargers” are the norm. That affords the livestock a chance to get away from the fence. Momentary on, then off for a period, then on, etc. Tip: Pull up a long piece of grass and lay it against the wire and watch it a bit. If its electrified, it will start small arcing where it touches when the current turns on.) One other hazard, if you are on the wrong side of the fence and the Brahma bull sees you… GOOD LUCK. It’s best to determine his location before trying to cross his field. Generally, he has the speed and weight advantage. YOU DO NOT WANT TO BE THERE. It’s also a good idea to find out if you can clear the fence at a dead run… it might come in handy later. (also why we typically had jeans that were torn at the lower leg from snagging the top wire when trying to get over it fast.)

          Man… I sort of miss the idiocy of my youth. (Yes, people can levitate. I’ve done it. Push a limestone rock off the top of a cut at an old lime pit and look down to see a coral snake between your legs and you will hover too!) Yes, I am a member of Homo Stultus, I know.

    • Meanwhile. This grinning PoS thought the cheering onlookers were there for him. Heads up dip$!^^…they were cheering because you were caught. He’s gonna have LOTS-o-fun in the Mississippi penal system.
      No real word on what prompted him to walk up to the patrol car and execute the officer. But I think those politicians who call for violence against law enforcement should stand trial with him.

      Side note: I don’t know if the video that accompanied this clip was at he unloading at his destination, but they had a K9 unit out walking around. If it was at his arrival, that means they were ready for him to bolt. That would have been funnier than @#$@.
      According to the news report, an off duty officer going home spotted him walking along the side of the road in Wiggins MS and called Wiggins PD to assist in the apprehension. From him not being on a stretcher, I don’t think he put up a fight. (wise move)

      Elsewhere, in Alabama. Police arrested a fleeing driver after someone threw a wheelchair out the window during the high speed chase. Turns out the driver was a paraplegic driving getaway for a robbery. They stole a 55″ TV.

      In general, if Floridaman™ doesn’t show up on the news for entertainment, our neighbors can fill the gap.

    • Carl is the specialist on this one. I would just point out that Hekla seems very young, young enough that the lithosphere is still adjusting to its weight. There probably was a pre-Hekla and it may be a bit arbitrary what is called Hekla and what not. But in general, taking the current volume of Hekla and dividing by 10,000 yr should give a fair idea of the eruption rate. And Hekla is not associated with a spreading ridge, so there is no need for filling gaps underground. Your number sounds right . The 1913 and 1878 eruptions were offset from Hekla so it is not excluded they sourced their magma from somewhere else. Heck – we don’t even know where Hekla gets its magma from. There is no heat source underneath it.

          • But if you poke a hole in another hole… how is that a layer? And why does it occasionally cough up a furball of magma chemicaly similar to subduction zone magma.

          • It is like Mauna Loa, formed by a central conduit into a rift. Hekla’s rift is rather short compared to Mauna Loa, but the two mountains have basically the same shape. You get this shape from asymmetric stress. In Hawai’i, the stress is lower north-south-ish because of the sliding of the island, making it easy to rift east-west-ish (this is not quite the direction but you get the drift). In Hekla the spreading centre gives a low stress direction, so Hekla is oriented perpendicular to that (along the spreading axis) even though it is too far from it to get much benefit.

            https://www.volcanocafe.org/dissecting-hekla/

          • It works like Hekla 🙂

            Remember, whatever can be done arsed-reversed, Hekla will do it.

            I was the guy inventing the term stratofissure volcano since I got tired of that the main-class of volcanoes containing only Hekla had no nomenclature of its own, so I named it stratofissure.
            Hekla-class sounded like an English class of old bomb-cruisers commanded by Perry.
            The rational was that it looks like a Strato-cone from the arse end, and it is a fissure.

          • Mauna Loa looks that way too, if you look at it through the wrong end of binoculars. Turtle, I wasn’t saying that Hekla was sliding, but that there is a direction with much lower stress. The reason is different, the effect similar. With such a young volcano, there is no telling what Hekla will do next. And with such a busy area, eruptions close together can be fed by very different sources.

            I think that Hekla is strange because it lacks a heat source. Which is very different from Mauna Loa.

          • That also happens with shield volcanoes, most shields are elongated along a rift zone, like Mauna Loa while some are cone or bowl shaped like the volcanoes of Galapagos, you also get triangular pyramid shield volcanoes when there are three rift zones like Tenerife and El Hierro in the Canary Islands, but no distinction is usually made between them. Regarding stratofissures I could think of some volcanoes that maybe could classify in there like Tarawera, Cordon Caulle, Dabbahu, Dubbi or Cumbre Vieja.

    • It was actually not me that bumped those from the official Hekla-eruption list. That was Professor Erik Sturkell. But since he is as awesome at discovering things about Icelandic volcanoes as he is at not being in contact with the rest of the Universe, I got the honor of spreading the word a bit.

      There is distinct and excluding petrochemical differences between Vatnafjöll and Hekla lavas that are mutually excluding a common source. Baring a full on article on the differences that I plan to write one of these years, I will just state it here (I have though referenced it in previous articles).

      Vatnafjöll lavas are though similar to the those distal eruptions at for instance Mundafit and Lambafit. If you wish for lavas like at Hekla you will have to meander off to Thingmuli.

      Also, the fissure swarms of Hekla and Vatnafjöll are different, also the tectonic and seismic regimen is different.

      To much Hekla pondering often leads to a need for cask strength whisky as one ponder who the evil bastard was that ordered a volcano that is a main-group of one volcano on the planet. Whatever any other volcano does, Hekla will do it arsed-reversed.

        • There is no vertical mixing in the magma chamber: there is a strict sequence of erupted material. That suggest no strong heat source from below. Perhaps the chamber is fed from the side.

          I don’t think Hekla is becoming more active. The 1947 eruption was large (smaller only than 1104) but one eruption does not make a pattern. It has moved to frequent small eruptions rather than less frequent larger ones but it has been 20 years now so perhaps it is changing back.

        • Turtle, let me here brutally state that we definitely know that the magma origin is not the same.
          Vatnafjöll is MORB/Plume-intermediary derived basalt, Hekla is alkali-andesite transitioning rapidly after about an hour to alkali-group basalt. Hekla is extremely rich in fluorine, Vatnafjöll is not.
          Basically Hekla seems to use pure Plume-derived basalt (no MORB) to melt up an underplating slab of oceanic crust.
          The same goes for trace REEs, way different.
          So we jolly well know that they are not related.

          Most people spend way to much time looking at the silica content, but it is just one tiny part of the puzzle. Especially for a volcano that is bimodal.
          Initial erupta is indeed high silica andesite driven at extreme levels of volatiles (producing the hellish opening phase that is extremely explosive. That quickly changes to intermediate alkaline basalt with high volatile content (causing those long distance lava bombs hitting farmers at Olympic marathon distances), after that comes the runny stuff with medium volatile content.

          Yes, the andesite is indeed very hot for being andesite, but that is not that odd since it is fed from a plume and probably follow another development regimen for separation than at other volcanoes.
          The best fit solution is that the stack is functioning the same way as a heat driven oil refining column exsoluting volatiles and light stuff to the top far fast than unheated oil (magma) would.

          My point in the end is that it is about as fruitful to compare Hekla to Grimsvötn or Kilauea, as reading the manual for an electric toothbrush and then try to fly a fighter jet.

      • Turtle, you are just plain wrong here. Almost nothing of the blue part has anything to do with Hekla.

        • I should here state that the reason Turtle is wrong is spelled Global Volcanism Program.
          They have refused to change their list of “Hekla-eruptions” for 7 years now. Regardless of the progress of science. It does not matter who tells them, IMO, Thordarson, Sturkell, and so on. They just go: NO CHANGE.
          Even Ian Carmichael had a try, but still NO CHANGE.

          So it is understandable that people get fooled. The official IMO list is quite different though.

  17. Impressive geological news, these from my home country Portugal:

    Portuguese scientists reveal proof that a SUBDUCTION ZONE is beginning to form southwest off the coast of Portugal and Spain, which explains the mysterious origin and intensity of the large earthquakes that occur periodically there.

    One of them was the famous 1755 earthquake and tsunami. But previously large tsunamis might have occurred in centuries prior to 1755, namely in 1722, 1531, 1009, 382, 33BC and 63 BC (some of these had significant tsunamis confirmed). In 1969, a M8.0 earthquake occurred also in the region, with a small tsunami.

    https://www.nationalgeographic.com/science/2019/05/tectonic-plate-peeled-apart-could-shrink-atlantic-ocean-geology/

    Shockingly, they reveal that another large quake may be just around the corner.

    The European Subduction zone is poorly known and understood, but has the ability to generate some of the strongest earthquakes in European continent.

    • Not the most reliable source, sadly. The original paper can be found at https://meetingorganizer.copernicus.org/EGU2019/EGU2019-6001.pdf and is a bit more restrained. It is not proof, but they say what they found may be a step on the way to forming a subduction zone. It is a deep area with fairly old crust, and a future subduction zone may form here, although it hasn’t yet, according to what I understand from the paper. Another quake near Lisbon is not impossible: it is a fault-ridden area. A repeat of the M8.4 Lisbon quake is not imminent, I expect. But other events may happen.

      • If a subduction zone would form, where in Portugal and Spain would mountains and a volcanoes arc form?

        Their absence is a clear indication that a subduction zone is just beginning.

        • Good question! A subduction zone may form in the next 20-40 million years, i think (the ocean doesn’t seem quite deep enough yet although it is getting there). You should get mountains and volcanoes (not necessarily in the same place). But it should also pull Europe apart. Spain is only loosely attached to Europe anyway. I expect that it will split from Bordeaux, through the Pyrenees towards southeaster Spain, helped by the rotation of Italy. So the Basques will be in Spain but the Catalans will separate from Madrid.

          • Looking at other subduction zones around the world, I see that most mountain and volcano arcs form about 400-600km inland from the subduction fault where earthquakes occur.

            So that would place the beginning of the mountains and volcanoes in the Rif-Beltic system…

            Obviously the subduction is just probably starting (geologically speaking) and it eill take a few million years until volcanoes form and the volcano arc extends northwards and southwards.

          • So, the Catalans will get their independence after all? But may have to wait 40 million years for it?

            And what the hell is going on with the comments? First I kept seeing empty comments by Jesper Sandberg. And now today a ton of comments by him and turtlebirdman have been changed to just “/Comment edited by Admin”. Including ones from all the way back on the 5th that definitely can’t have violated the rules or they’d have been edited long before today. I don’t think older comments that were not considered at the time to be violating the rules should be edited like that, especially not if they have replies, as many of them do. It makes it much harder to figure out what some of the conversations are saying!

          • See rule number 2 here Irpsit.
            We also remind about rule number 1. This comment was not especially nice.

            /Dragon with Katsup bottle.

  18. After rereading the comments above I leave the debate.
    It seems to be quite fruitless to be honest.
    I do not have endless time to correct every single error. Nor does it seem that the answers are read.

    I have pretty much written all I have to say about Hekla in my articles and will happily in the future limit myself to writing the articles without commenting. This has become a farce.

    /Elvis has left the building.

    • Bull$#!+!!!

      I find your discussions on Hekla to be quite entertaining and eye opening. The whole reason I mentioned Hekla’s odd furball magma was due to something you mentioned months ago. I still can’t come up with a plausible explanation for the strange stuff. That’s why I stick with the stacked slab idea to account for the odd stuff since a bonafide subduction zone existed in this region back before Iceland even formed. With the Jan Mayen microcontinant crust sitting next door to Iceland propper, I see it as proof that REALLY strange tectonics have been at play during Icelands formation. So the stranded subduction zone crust remnant seems more plausible to me as at least a partial explanation for Iceland’s anomalously thick crust compared to other oceanic volcanic islands. This is the only reason I don’t really buy the “Hreppar starting to subduct” idea.

      Other than that, I have no issues with your statements on Hekla. After all, I’m here to learn from the knowledgeable.

      And to occasionally be a jerk.

      • From my time living for 4 years inside Hreppar (in Iceland!) I also came to the assumption that Hreppar cannot explain for the explosive behavior of Hekla, or that a local subduction is happening. None of those hypothesis make sense for me.

        I ask instead some interesting questions:
        – Why is Hekla so rich in Fluoride? What does that mean?
        – Are there any similarities in the magma specific to only Hekla and its neighbor volcanoes?
        – Do any other volcanoes exhibit magma related to Hekla
        – Why are two unusual non-basalt volcanoes next to each other? Hekla and Torfajokull (rhyolite)? Could there be a common explanation for those?
        – Are there any crust anomalies specific to Hekla region? And why aren’t there more “Heklas” in other parts of Iceland? Why is Thingmuli case similar to Hekla? What does that mean?

        • Also confusing Vatnfjoll with Hekla is a bit like confusing Veidivotn with Torfajokull. – It’s an easy thing to do.
          – Both are distinct types of magmas
          – Veidivotn basalt magmatic intrusions sometimes enter the Torfajokull rhyolite caldera and trigger eruptions there, and both magma types erupt very close to each other, at same time.

          Could it be possible that basalt feed directly from the plume trigger the same at Hekla (which has its own different and unique magmas) and explain the dual magma mode of eruption?

          • More of doing a phreatic blowhole on the FB backchannel.
            Gaz and Tommy calmed me down a bit. 😉

          • The phreatic blast seems to have swept away a lot of comments on the blog as well. Personally I think that’s a bit sad to see. I thought the blog only had one rule – “be nice”, but maybe we should add a “be correct” rule as well? I understand the frustration, but these are two enthusiastic young persons who sometimes get a bit over exited with their comments. It would be a shame to see them lose their passion. It’s not like the cryptodome guy who was trolling the blog after Holuhraun.

          • Yes, that is a pity. We lost some discussion there. I would side with Carl in the discussion, in that there are eruptions around Hekla that have nothing to do with Hekla’s magma reservoir, but in some cases it may be less clear what is what. Although Hekla is quite recognizable.

            Eldgja is an example of an eruption that produced two different magma types. Along most of its length, it was Katla. But at the far end, it ejected some magma for the other side. After Leilani, I now think this was old magma left in the rift from the Vatnajokull side, which Eldgja managed to push out. The same location can apparently be fed from different magma reservoirs at different times. Iceland is funny that way. Or perhaps that is just the dead zone.

            I do wonder (in general) how accurate volume estimates of lava flows are. Turtle assumed a thickness of 5 meters. What I have seen at Kilauea is that this may be reached in places or after a lot of time (i.e. Pu’u’O’o did this), but most of the flows I saw in motion were nowhere near that thick, and were tens of centimeters, not meters.

          • It seems like an admin removed a few comments.
            This is not a redo of the rules. Just something that had to be done in this particular case, and that we regret that we had to do.
            We do hope that the message of not drowning out things completely will be understood.
            Let us write it up on Special Circumstances of The Culture. (Ian M. Banks for reference).

          • I am siding with Carl on this one.
            Free speech is one thing, provocations masked as “debate” are another.

            It was never about being correct, but the problem was flooding the comment section with repeated stuff that is off topic (which is also not that big of a deal) and/or borderline fantasy. And asking questions to get a reply from a specific person, just to then throw 10 more replies at them, basically with repeated content from the previous 20 replies.

            I guess some self-control is always welcome to keep the debate on a normal level.

        • I even have the intriguing hypothesis which is: could Vatnfjoll magma be just an extension from Veidivotn dead zone magmas?

          I left that question to the ones that know the chemical composition of both magmas…

          One day we will see again an eruption of Vatnfjoll and also at the 1913 region. And then we will have a more deep understanding of what is going on. Just like with Holuhraun, we may be surprised…

          • It is not entirely out of the question, sort of. It has its own root-feeder, as is evident on a plot that Andrej did for an upcoming article.

            That being said.
            If one would extend the fissure swarm of Vatnafjöll just a few kilometres more it would hook up with Veidivötn.
            Let us say that it at least seems to be downstream of the same magma source.

          • The next eruption of Hekla will be much better recorded than any before, thanks to all the hardware upgraded. The seismic data should really light up its internals and we should get a better picture of whats below ground.

            I did a cross-section over Hekla fissure SW-NE, and it revealed interesting things, like a quite possible deep source NE of the summit.

          • Bigger questions arise: why activity in Vatnfjoll was high and now dormant? In same manner, why does the same occur with Reykjanes volcanoes? Até other volcanic regions taking up the rifting during the periods where other regions become dormant?

            Could this explain the seemingly alternation between Hekla and Vatnfjoll? Does the same dynamic explain the active/dormant behavior of other Icelandic volcanoes?

          • Andrej, is that deep region NE of Hekla the Lambafit region? If so, then we could be seeing the early stages (deep quakes) for an eruption there…

    • This could be disturbing, if humanity does little or nothing to do something about all those greenhouse gases being dumped into the atmosphere.

      At this rate, I’ve read somewhere that the Vatnajokull ice cap could be gone in as little as 200-300 years, This could mean more frequent eruptions, obviously. During the Last Glacial Maximum about 18,000 years ago, Iceland was entirely covered in a thick ice sheet. This apparently had the effect of suppressing volcanic activity until the early Holocene, when volcanic activity resurged quite a bit.

    • And IMO have followed the shrinkage and ever so quietly changed out their maps that they plot things on. You can see it a little on the Vatnajökull plot, but the really changed on is the second largest glacier, Langjökull. Poor thing has really worked on fitting in those slimline pants.

      Þar kemr inn dimmi dreki fljúgandi,
      naðr fránn, neðan frá Niðafjöllum;
      berr sér í fjöðrum, – flýgr völl yfir, –
      Niðhöggr nái. Nú mun hon sökkvask.

      There from the mists the dragon flew,
      adder from, down below Mount Niða;
      The feathered bear – flown far above,
      Shocking grace hits. Now clean she will.

      (translated from forn-Nordic, not Icelandic, to modern English by me)

      • What did the original map look like? I can’t remember it well enough to compare (and wasn’t able to dredge up a different map than this one after poking around their website)

        • I have been hitting myself quite a bit over the head when I finally noticed it, because I wish I had the originals. This one was exchanged in 2015 as par example. And I did not notice it until 2018.
          On older glacier maps the glacier pretty much covered the upper caldera, and more parts of the lower. Let us say that it will soon be Shortjökull instead of Longjökull, and that it has gained a definite midriff…

  19. Comment deleted due to rule violation.
    All discussion about moderation is to be done via email.

      • /24 hours to ponder reading what people write.
        The rule broken is once more this one: “All moderation is to be taken privately via email with the moderators.”
        It was stated by an Admin above, and by Carl further up.

        • Alright I think everyone should just drop this now. I know it’s not my place to tell people what to do but this isn’t going to end well if this conflict continues. I’m not taking sides and there is no need to.

          In future, let’s keep conversations concise- it does overshadow other things sometimes (this applies to everyone not just Turtle and Jesper)! The last thing we want is to potentially repel/dissuade future contributors. A little diplomacy goes a long way- it isn’t a competition!

  20. Did a quick plot of the Herdubreid swarm. Its in a region where at that exact point we have not seen a swarm yet, or at least not a recorded one.

    For a historical perspective I am adding a plot of historical data, where you can nicely see the deep feeder root of Herdubred and also a possible separate root for the Upptypingar activity.

    • Herd seems an underrated volcano in view of her big sister in the West and her big cousins in the South or North. But everytime I see those beautiful plots of you Andrej, she reminds me that’s she’s like a little child screaming for attention. One day, her family who buried her 10.000years ago, will be amazed by wizardry in their backyard. That’s because she was a little late to the party of the plume and hotspot. Though since she’s a wizard now, she arrived precisely when she meant to. That’s enough word play for me for this week.

  21. I will here give a short statement on why we did what we did.

    It had nothing to do with matters of opinion.
    It had to do with the regular commenting being drowned out.
    We have for months received numerous complaints from many commentators who have chosen to leave Volcanocafé. We have therefore numerous times over several months given warnings to two persons, and told them that this is a problem. No heed was given.

    As the comments was cleaned, every single one that was on topic was left, all that was OT was removed. As you all can see the ratio is unsettling to say the least.

    We have always allowed OT, and we will not change that, but if 90 percent of all comments written by a person are OT, then we have to take action against the person performing that massive OT-fest. And, we have pointed it out several times that it is time to cool things down. It was not advice heeded.

    The option was banning. Make no mistake about that. It was discussed, instead four different admins voted early in the morning (unanimously) for cleaning OT from the persons involved up until such a time that we have a new chat-room established for that specific purpose.

    We have generally 3 rules in here.
    1. Be nice. We found that it is not particularly nice to drown out other commentators with 90 percent OT comments, and the bulk majority of the comments above was OT written by two people alone. For this we cleaned.
    2. All discussion about moderation shall be taken via email with the administrators. This rule was soundly broken above, a warning was given out, that warning was disregarded, and a 24 hour ban was handed out.
    3. Do not spam. Well, see the part about 90 percent OT.

    In the end, we have tried to control things, but they did not listen. Even if this seemed brutal, the option was either permanently ban, or even for a while shut down commenting.

    I once more remind about Rule 2, if you have opinions, or suggestions, about moderations. Send them in via email.

    • Good to see this wrapped up. I hope that’s the end of it and we can ‘reset’. And I do sincerely hope the two- shall we say ‘over-enthusiastic’- people do come back. They do contribute even if things went a bit wrong. I guess you can say everything is good in “moderation”- hahahaha!

      Last thing on this from me- perhaps when someone does want to “go off” on a gigantic tangent, they could upload their comments to a free text host and put a link here or something so they can still post but not flood the chat?

      Anyway, that’ll do.

  22. Now, back to Greip.

    At 15.35 there was an earthquake registered there:
    Wednesday 08.05.2019 15:35:03 64.576 -17.190 24.3 km 0.7 99.0 17.6 km ESE of Bárðarbunga

    The earthquake had an initial clean break at 15:28:05 and had a duration of 8.5 minutes.
    Obviously this is not an ordinary run of the mill earthquake. Also, it reverberated across all of Iceland, and is detected by over 90 percent of the seismometers there.
    Such a long coda is normally only associated with movement of volcanic fluids, and there is no particular reasons to assume otherwise here.
    As such, it is the clearest volcanic earthquake detected at Greíp so far.

    • The thing that ticks me off is that Iceland has seismic gear out the wazoo compared to other locations… but only one station over in Reykjavik appears in the global network with raw data available for download. It’s not anyone’s “fault”… it just falls outside the reason for IMO’s network and wouldn’t support their mission goal of public safety.

      I guess my issue is that there’s no one to be mad at about it.

      • One of the reasons for the Reykjavik thing can be blamed on the GPS system on a global scale. REYK is one of the global reference stations, so they also hand out raw feed for the seismo, so that it will be possible to track changes due to larger earthquakes.
        On the other hand HOFN (the reference for the Eurasian part) does not come with a public nice seismo via IRIS.

        I think that it in part is due to IRIS, the Icelanders can easily set up a system able to send out all the data via IRIS, but I think it is IRIS that does not have the capacity for gizmos playing kazoo out of the wazoo.

        • So you are saying my assumption is correct, that I have no one to be mad at?

          … and it really doesn’t matter at this moment because I can’t find my @#$@ software, and a snippet from a seismology book where I remember a nugget of really cool stuff you can do with an FFT of the waveform. It was something about estimating the size of the responsible fault face. No one take this as fact, but if I remember correctly, the frequency of the first knuckle (roll-off) is related to the fault face size. The long coda indicating fluid movement would probably not have anything to directly do with it.

          I think it was in “An Introduction to Seismology, Earthquakes, and Earth Structure” by Stein and Wysession (Blackwell Publishing), but I am not even sure of that anymore.

          • It sucks to have nobody to be angry at for these things.

            Yes, in a “normal” tectonic earthquake the energy level of the initial break relates to the length of the earthquake energy release, thusly giving the area of the fault plane.

          • Good morning,

            Does this quake represent a change of behaviour in this situation, one worthy of more discussion?

            If the quakes until this this point were techtonically generated from the pulling apart of the plates (or lesser magmatic) quakes is this reverb magmatic intrusion quake signify maga on the move to fill a space?

            Is such a quake a continued statement of intent by Greip or is Greip now saying more?

            Richie
            (Long time lerker, seldom poster)

          • Hello Richard!

            It does not represent a change in behaviour since the earthquakes have been caused by intruding magma from the start.
            In a way this is from the beginning being caused by the strain of pulling apart has created a weakness at this spot, but that was done prior to any of the current activity.
            What is different was the level and length of tremor, and how large area of Iceland it was visible at.
            See it as an increase of the level of activity and an indication that the root-feeder intrusion rate has increased.

    • As Carl says ( keep to the subject in topic )
      Is there any other studies Done on Greip area that suggest there is indeed a forming central volcano there?
      This Volcanocafe Greip data is excellent and soon detailed enough about Greip that a PHD may be written about this subject …
      Im excited about more information on Greip
      Andrej Flis data is turning out be very valuble in understanding this arera

      • With regards to Andrej Flis, I have to agree. His plots are first rate in my opinion.

        As for the pHD thing… well, I’ll keep my mouth shut. I’m not one but I know of a couple who have been poking around at the topic. 😀

        As for removed comments, no one should take it personal. I’ve even had a comment or two removed from the thread flow by the other Admins. (For being obtuse and/or wildly off topic)

      • No, Greip is indeed a VC special, there is though a paper on its deep feed that Gaz referenced in the text. It may have been involved in the Holuhraun eruption in 2014. So, we are not alone in having noticed it as a volcanic feature, but we are the ones proposing it as a budding little central volcano.

        And it is not only Lurking that has been edited a wee bit by other Admins… It has happened to me too. We apply the rules every bit as hard to ourselves. And god only knows that we can go off on tangents and go OT from time to time. That being said, it was the volume of things.

        Have a nice day Jesper.

  23. I commend the moderators, although they are perhaps too reasonable.

    For a little while I have just scrolled past lengthy and (to be honest) boring posts by certain people, which means I miss anything of interest they may have said amongst their own noise. I have been in usegroups (unmoderated) that have been destroyed by a single person despite standard software allowing easy ‘killfiling’ and it would be tragic if this happened here.

    Note this IS a moderated group, even if the moderators have chosen (generally correctly) to moderate with a light touch and to ban only in extremis.

    This does have a commensurate moral obligation that users in general should do as they are requested by moderators, if they do not then actually its the moderators painful duty to ban them for the good of the group.

    It should be born in mind by all users that moderation is actually an onerous and time consuming job with zero pay and consuming much time and effort and users should avoid making it any harder than it already is.

    To end: thank you gentlemen moderators (and ladies if any).

    • Very good comment that I can only second, together with completely backing the stricter moderation of comments.

      Thanks Gaz for this very interesting article. Props for the section on yourself, keep on going!

      Everytime when the connections between the different volcanos are discussed I get the impression that Iceland is just one huge volcano with various chambers/vents that can “flirt” with each other, depending on the local stress/pulses from below. The idea of an independent central volcano is a bit blurred when it comes to Iceland!

        • I do not think I was the trouncer, but I have no memory these days, so if I was the trouncer I have changed my view on the subject.
          Reason I think I was not the one is that it in a sense of it is correct, at least for the volcanoes mostly affected by the plume.
          The entire concept is though running completely awhack with the collected wisdom of volcanology, so we would have to do one heck of a job to prove it.

          • I think it has to do with the setting of the volcano, in Hawaii you are never going to see one volcano interchange magma with its neighbour. Each volcano has its area of intrusion and you do not mess with someone else’s rift zones, they butress each other rift zones, seem to compete for the same supply (at least Mauna Loa and Kilauea), and they do want personal space, Mauna Loa gave such kick to the edifice of Kilauea in 1868 that it collapsed its caldera. Though they might push between them or try to suffocate the other under basalt, appart from this rather competitive interaction there doesn’t seem to occur any exchange of magma of any sort above 30km depth from where they behave as central separate volcanoes.
            On the other hand, continental rifts or spreading ridges like Iceland probably make it possible for volcanoes to establish connections by sharing fissure swarms. As an example from somewhere else, in Afar three volcanoes: Dabbahu, Gabho and ‘Ado’Ale shared the same dike intrusion from 2005 to 2010, ‘Ado’Ale even seems to have inflated Dabbahu and Gabho over the years after the initial intrusion was over, all of this known thanks to InSAR. I don’t know much about Iceland but I recall there being evidence of something similar having taken place on multiple occasions in the past.

  24. OT: I always thought there was only one image of Bezymianny pre-collapse, but I found this on KVERT’s site, apparently from 1946 and was in a 1955 Soviet book on Kamchatka volcanoes:

    • Here’s more or less of a literal translation (Caveat: I used Google Translate and and another site – I do not know Russian, although I can tell apart letters to a limited degree):

      Fig. 1. Volcanoes Kliuchevskaya, Kamen’, and Bezymianny (from left to right). View from the west. In the left corner – the far flat volcano.

      That volcano to the far left of the trio is Ushkovsky (formerly Plosky, which basically means “flat” in Russian).

      At least Google Translate can translate from Russian better than Icelandic!

  25. Iceland has become a quiet place in the past few months. Of course there’s a lot of more or less hidden activity which will lead to a new eruption but there’s nothing pointing to an eruption in the next weeks or months.

    The re-charging of Grimsvötn is going on at slow pace (I have to admit that I expected an eruption in spring or summer 2019 but this is most likely not going to happen it seems).

    Katla has become very quiet and the activity at Öræfajökull has also decreased. And of course, Bardarbunga has also become less noisy.

    Maybe we are looking at another year without eruption in Iceland?

    • Things can change quickly in Iceland. There are a few volcanoes quite capable to kick off rapidly, if we do not count Hekla I would say that both Katla and Grimsvötn could kick off with just a few weeks of pre-action, and a few other with a couple of months of seismic activity.
      But, I agree… With the exception of Herdubreid and Askja it is looking pretty dry so far.

      • Speaking of Hekla:

        Miðvikudagur
        08.05.2019 22:42:58 63,993 -19,697 1,5 km 1,4 99,0 1,5 km V af Heklu

        It’s shallow and right under the edifice, so could just be settling from the weight of the mountain, but it is a bit larger than usual for Hekla.

      • … And again I have an eye on the area around Herdubreid.
        Although I don’t know the exact location of the sensors. Nor do I know what sort of signature the local quakes have.
        But I notice that they continue to get more shallow.
        No expertise here.

    • Ouch, I feel sorry for Burns who was quoted wildly out of context.
      And the hysteria in it reached new levels of inaccuracy.
      Only one sentence was correct, that large eartquakes can cause landslide. They stuck that at the bottom.
      It was exactly as Tallis wrote, a horrible article.

    • The way to make the Daily Express collapse into its own caldera would be to tell them that Brexit causes volcanoes.

    • You know its legit becouse of the UFO stories.

      What was that old saying again.. The news generally is very reliable.. except in the subjects you happen to have knowledge in.

    • If I’m not mistaken the caption translates literally as “changes in land elevation”, so I would say yes.

    • This is from the Hotspot I think?
      Its located in the plume arera in Iceland
      Looks like magma is accumulating in Vatnajökull area.

      • Yes, it is accumulating in the Vatnajökull area, as should be expected from the plume. Things did though change a bit just after this one, Skrokkalda stopped inflating, and the plume pulse came along moving the center of the inflation a bit to the north.

    • The figures are basically correct, but slightly understated compared to the later figures in regards of Katla Hekla area, and compared to the Kistufell, Trölladyngja are.
      There also effects to take into account for Askja and Theistareykjarbunga in the longer time series compared to this, the inflation is increased in later figure for Theistareykir and Askja has reversed from deflation to inflation. It also does not take into count Herdubreid and Greip area.
      Much has happened in Iceland in the last 15 years. 🙂

      • It would be very a very informative plot to see updated to current data or even a dynamic one over time to show how the movements changed

    • It is definitely one of the volcanoes I am having on my watch list. Taal is pretty much under-rated and can definitely do a fair bit of damage.
      Also, it is a highly interesting volcano with a lot of various sorts of faults and other activity causing trouble even when it is not active.

    • Keep your eyes on the news for a fish die-off. Taal has a lot of aquaculture endeavors going on there in the lake. Mostly Tilapia. In fact, I’m thinking about trying out a smoked tilapia recipe for just that reason. Sort of a curiosity and a sick volcano fascination.

      And while I entertain my volcanic perversion, and quick note about the subducting slab that feeds the volcanoes in the region. The Palawan Continental Terrane is just that, “continental.” That means that the melt derived from it will not be as juvenile as oceanic crust. This may be part of the reason that Taal formed a “Large Caldera” rather than a tall mountain like Pinatubo, just under 150 km away. Pinatubo is offset to one side of the Palawan terrane in the grand scale of subduction there along the Philippine Mobile Belt.

      Note: My idea has not been vetted with the other Admins. and I could be blowing smoke. It’s just an idea anyway. Mr. Jim Beam and I have been sitting here discussing it. It’s amazing what 8 year old Bourbon can convince you of. No, don’t worry, my keys are on my dog’s collar. I’m not stupid enough to try that. I’ve seen first hand just how far FHP will reach for a bust. (I wasn’t the target, I had just gotten finished holding a victim in place while EMS was removing the seat-belts and stabilizing the patient that was upside down.)

      The messed up bit? According to the skid marks, the upside down guy caused the accident and the one they nailed for DUI was the victim.

      As far as I know, everyone survived… except for the DUI guys wallet.

  26. And, while I am enjoying my refreshments, I’d like to say that your guys are world class students. I’m not a teacher, but I was at one time, a qualified US Naval Instructor. You get pretty good at reading students after a while, and you guys are quite good in my opinion.

    The kick arse part about it, is that you require almost no motivation to seek answers to the vagaries of Volcanoes and Geology. Now, as I have mentioned in the past, I am not qualified to provide authoritative answers to your questions. My level of experience comes from a keen interest in the topic and the patience to wade through numerous papers about it. That being said, the KEY to being an instructor, is the ability to assimilate information from the actual experts, and to relay that to your students. During Instructor training, several of our “Lab” topics was to develop a lesson plan about something that we knew fairly well, and to present a class-room session on it, complete with visual aids and what not. For that reason, I have had a short course in Egyptian Mummification techniques, as well as the proper way to change a spark-plug. (Other student’s lesson plans, no direct connection to the USN, just a student instructors chosen lesson topics) My specific lesson was on reading and interpreting resistor color bands.

    ..But, as a two tour instructor, I have had a few hundred students in my experience. Ranging from a likely confused young woman with an apparent over-active libido, to a self proclaimed vampire. Both of them did not make it through training due to complications of their own making. (The girl was likely just experiencing being out from under an overly authoritative parental environment for the first time, and the Vampire kid, well, he had legal issues witch kept him from returning from a mandatory court date in his home town.) I’ll not detail the two here. Either one could be a reader here and I don’t want to say anything embarrassing to them. My point is, I’ve seen quite a few students. The hardest part of teaching ANYTHING, is developing an interest in the student. Since you AND I are all students of this topic, I think you guys are quite good. Now a secret…. {grin}, there are at least two pHDs among our staff. They usually act to keep us other admins in-line and within the bounds of sound science. 😀

    Personally, I’m a two time drop-out, but I respect the attention to detail and rigor that the pHD’s bring to our articles and discussion. {The hilarious bit? My first drop out I had a GPA of 0.57. The only thing I could pass was Calculus and Psychology. I even had computer Science as an incomplete… and here I am working in that field… WITH state certification. As well as CompTIA.} Homo Stultus LIVES!!! 😀

    Either way, Volcano-cafe thrives due to you guys. Many Thanks!

    • I concur absolutely.
      Former training officer for a major UK charity specialising in paralegal work, and a big time advocate of learner-centred learning.
      That’s what we get here, over time.

        • Not personally.
          I was based out of the West Midlands area office in the centre of Birmingham. Most of my training was in that general vicinity.

    • A less than flatering side note about the female “Problem çocuk”. Due to a few years under my belt, I had a nagging feeling in the back of my head about sending her to NavHosp under instructor escort. All but one of my instructors were male. The only female instructor I had available was a veritable thorn in my side when she was my Leading Petty Officer. Since I was promoted past her, she then worked for me. One thing that caught her unaware was that I kept her as the LPO for the work-center. She figured that I would be vindictive… which I was. She was a “hard ass” at her job and she did it well. I wanted that as an LPO. I tasked her with escorting the problem girl over to NavHosp in order to protect my male staff from bogus charges. That was just the sort of vibe that I got from that girl. WImp move on my part? Yeah, but it saved a lot of heartache and likely a career or two. When it came down to a final disposition of what to do with the girl, I looked the female LPO in the eye and asked, “Would you want her in your shop?” She replyed “No” and that sealed the deal for me. I recommended drop from training. “Administrative Burden

      Note for all, just because a Female supervisor may seem to be a jerk, that doesn’t mean they don’t know what they are doing. I made my former difficulty into an asset and it kept my shop in top working order. I transferred before I could find out, but I am almost certain she got picked up for CPO in a later cycle. She may have been a jerk, but sometimes that’s the only way to get an onerous workforce to follow the guidelines. She isn’t there to be a friend, she’s there to get the job done. {Note, this applies equally well to male jerk supervisors. I’ve played that role as well. When you are pushed up against a wall, you make it happen, period!}


      In a similar vein, I had the toughest, meanest OS2 in my watch section “ride herd” over the other females in my watch group in order to keep their on watch activity in line with command policy. Every time the evaluation cycle came around, I gave her high recommendations to her CPO.

      When it came to on-watch conflict with “the girls”, I backed her up every time. OS2 Thomas, I actually miss you. You were first-rate.

      EWC(SW) {ret}


      “Problem çocuk” that’s the way the title of “Problem Child” was spelled on the movie poster in Ismir Turkey.

      • OPINION. In the US, Women in the military is an occasional issue that pops up in the news. Having seen it first hand, the problem is not women per-se, but how men deal with it. It flat out skews the action men will take in a dire situation, and also tends to affect their normal behavior. It’s called “Being Human” and there is nothing you can do about it with policy or rule changes. The IDF seems to have found a method to make it work, but I don’t know the details. All I know is that I had to rely on highly professional and well motivated women to overcome issues that I had with those that were non-complaint with command directives and policies.

        Any thing more would be well outside the bounds of Volcano Cafe’s standards and topics.


        SOMEWHERE in this house, is a brand new 18V Lithium Ion battery still in it’s plastic packaging. Beats me as to where…

      • My time in the army came in two distinct versions.
        First came 150 days of basic training. It was very loud and came filled with people screaming about making the bed, shining shoes, and push-ups.
        The change to the rest of the rather long time, it was like a switch was flipped. All of a sudden we were supposed to solve any problem coming up without the screaming part and being told how to do everything loudly.

        I thrived on the second part, but soon noticed that many did not. Those disappeared over the next 300 days.
        After that the cycle started over and I discovered that my great military short-coming is that I do not especially like screaming at people. I did it, but it was noticed and I was circled out of the yelling part into ops-planing and ops-execution (also known as problem solving).
        After a while I circled myself out, but due to the vagaries of Swedish draft-laws I have been circled back in a couple of times as some problem or other needed solving.
        Now many years later I have come to the conclusion, you either train your soldiers mercilessly in problem solving, or you scream at them. I know which type of soldiers I dread to meet in the field.

        Morning rambles before coffee… Anyways, I like your keydog solution. Nothing worse than drunk drivers.

        Oh, and in regards of the PhD part. Mine is more of an addendum since I had nothing more useful to do in life after leaving the army. I am not in any way a serious academic since I am way to easily distracted and tend to quite literally meander off for new problems to solve.
        I am a hack compared to the other PhD, who has made a life out of being one of the best scientists in the game. I am more of an over-educated science writer.

        At work my staff has since a long time learned that it is a good idea to keep me away from anything tedious and that involves routinely doing the same thing. That leaves me free to meander about solving problems and coming up with my usual hair-brained ideas. Everybody is happier that way, and routine things that needs to be done will be done (amazingly well really) without my interference.

        The hairbraned ideas normally comes equipped with me running in blathering all over. It is amazing that my staff is still remaining, they do though groan quite often.

        • “Keydog” isn’t really a full proof preventive measure. Doggie will come over and love on you no matter your state. Unless you are an obnoxious drunk… in which case it works better because the dog will run. But with the dog having your keys, it does make you stop and wonder why. Sort of a reminder that you’re not in any state to make decisions.

    • Actually there seem to be 2 swarms; 1 at Herdubreid proper, the other one some kms more to the south east (Herdubreidartögl?).
      I guess there’s some chance of an eruption there. If – and really if – there is an eruption, would we be seeing some sort of Icelandic/Hawaiian fissure style or more of an explosive, strombolian style with a spatter cone?
      To me, it seems there’s at least 2 separate dykes or sills forming, driven by fresh basalt. Could it be it passed the evolved magma chamber of Herdubreid, or should that chamber be locked and sealed since there probably wasn’t an eruptive period since the Holocene; for more than 12.000 years?

      I’ll go back and read the previous article:
      https://www.volcanocafe.org/seismic-unrest-and-the-future-of-volcanism-at-herdubreid/

      • I agree. This region has been having earthquakes for years, and many deep quakes, including several intrusions. The inflation is still small in instruments, but I am unsure how near Herdubreid most stations are.

        There is a change of an eruption at this site, which could start as an explosive one, and then become effusive, something like a VEI3. So far, things do not look out of ordinary.

        I have no sufficient data to make an educated guess whether an eruption is likely or not.

        • Having no expertise and limited access to data I can only offer the observation that over the last 18 months or so, quakes have been getting progressively more shallow.

          I think that if it actually erupts, we’ll have a very noisy period first.

      • Herdubreid stands in the largest pahoehoe flow Fields in the entire Iceland
        The whole North Rift Zone is covered by pahoehoe lavas of diffrent ages
        This huge flow field is called Odadahraun I think
        I think its acossiated with Askja and other central volcanoes in North Rift
        It shows that eruptions can last for years and decades as slow oozes in that arera.
        There are lava shields too in that arera ( more than 3 and 2 large ones ) looong slow Puu Oo like phases

Leave a Reply