Greip update (June 2019)

After a wonderful series on Krakatau by Albert, a mysterious island by Carl and a seismic “Intermezzo” by Lurking, I have decided to take things back to Iceland for a while. Most of us know Greip by now, and we are going to take another look at it, from a more seismic perspective with some fresh plots.

Here are links to last two articles on Greip, by Gaz and Carl. They contain important information and theory on Greip, which is a must read.

https://www.volcanocafe.org/greip-expectations/
https://www.volcanocafe.org/getting-to-greips-with-things/

After all these posts, what is there even left to say? Greip has not erupted (for now) and it just does what it does best: transporting magma upwards in a noisy fashion. I like to follow all the data I can get on Greip, which is for now mainly seismic. Carl has talked about GPS signals in his post linked above, but it’s not easy, since Vatnajokull is rather crowded with volcanic features in that part.

This year so far, was quite productive for Greip. In January-May period, we recorded the highest number of earthquakes for any 5 month period in Greip so far. That is also due to the better monitoring equipment in last few years, but generally in the last decade (or prior), no period comes close. For this purpose I have produced a new type of plot for Greip, where we can see earthquake numbers and the seismic moment release. Both parameters are part of the story. Data used for the plot was filtered by depth and magnitude. Holuhraun eruption period was also removed due to obvious reasons. It produced noise since it was in the same region as the plot. Some of the earthquakes in 2015 are also cooling quakes of the Holuhraun dyke, but it would be too hard and time-consuming to manually filter and remove all that data. So I decided to use cut-off filtering at 9km, which is very effective, since that is the upper limit of Greip core and lower end of the Holuhraun dyke. In the 2001-2012 period, there were M2s recorded and a lot of higher-end M1s, which over those years pushed up the energy total, while keeping the earthquake numbers at a relatively low count for such a long period.

GREIP moment energy and earthquake numbers. By Andrej Flis (@Recretos)

It is obvious right away that the earthquake numbers are increasing. Energy on the other hand, is stagnant or even reducing. It takes more and more earthquakes to release the same amount of energy. What this obviously tells us, is that the magnitudes are reducing. We see weaker earthquakes, but more in numbers. The most obvious and “practical” reasoning behind it, is that the crust in the core area of Greip is getting cracked to the point where not much more strain can be build up for stronger magnitudes. Total moment energy release so far from Greip core (9km+ depth), based on the data recorded in the catalogs, is equal to an M3.4 earthquake. That is earthquake energy only, not including the accompanying tremor energy. That is a decent amount, considering being in the hotter/warmer part of the crust.

On 31st. May 2019 we have seen one of the strongest dyke intrusions at Greip in the past few years, with tremor being recorded/detected on SIL stations from Askja to Katla. There were 17 earthquakes recorded in the core with that dyke intrusion, but the strongest earthquake detected was just M0.9 in magnitude. Crust in/around the core area of Greip is likely getting hot and cracked enough to start slowly loosing its “structural” integrity, which slowly reduces/limits the amount of solid/cold material to crack in higher magnitudes. The crust around it is likely still strong enough that higher (M2+) magnitudes can happen, if there were dyke intrusions outside the current main core area. But that is currently low probability, since the dyke intrusions seem to be focused very well on the specific area for now. I usually compare such “dyke swarms” like Greip, to lightning. Just like lightning, magma also pushes in the path of least resistance, with each individual dyke intrusion being like an individual lightning bolt.

A lightning analogy to Greip. Image by: Wilke See-Tho

The drumplot from the DJK station (the closest station to Greip), shows the dyke intrusion at Greip from 8:39am UTC to 8:51am UTC.

DJK station drumplot. Graphic by IMO

Looking at the magnitude vs depth distribution, we can see that the main area of energy release in Greip is between 10-20km deep. Below that, it is possible that the crust is getting too hot/ductile, or the main cracking has happened well before monitoring began on a high enough level. I used 2011-2019 data for this plot, which is the period where monitoring was getting a lot better across the region. Data was filtered by depth, showing only earthquakes below 8km depth, to remove some of the noise from the cooling Holuhraun dyke (LD2). This plot does not show any actual shape of Greip, but only presents earthquake magnitude distribution by depth.

Since this plot includes long-term data, I asked myself how the Holuhraun seismicity fits into this model. I have made a few cross sections that include Greip and the LD2. What is notable right away, is that the Holuhraun dyke is not completely linear in vertical shape. It made a turn at around 10km depth, tilting NW, away from Greip core area. It is also slightly tilted away above 9km.
To explain the graphic, we are looking at the data within the yellow lines (cross-section). Blue is the Holuhraun dyke, red is the pre-eruption seismicity, and white is post-eruption seismicity. White dots in LD2 are cooling earthquakes. We can see a tilting of LD2 starting around the area where the Greip core starts, and going down in a similar angle as Greip goes up.

Looking specifically at pre-eruption data we can see how Greip core was well established. Some older data includes shallower earthquakes, which are not really seen since the monitoring grid upgrades, so it is hard to judge how legitimate those locations really are. But the Holuhraun eruption and its related seismicity did affect the stress fields in the area, so it could be related to that aspect.

And comparing with post-eruption seismicity till the present time, we see the cooling quakes in the LD2, and a very good-looking Greip core area, which by this time has a more circular and cylindrical shape. It does seem expanded a bit towards E/SE, while the border between LD2 and Greip to the NW remains fairly stable. This data is also of a higher quality/accuracy, thanks to the much more sensitive monitoring grid.

Looking at the longitude components from Greip (9km+ depth data), we can see the slow movement/expansion towards east in recent years.

Looking specifically at the seismicity in the past year, we see that Greip is tilted/leaned slightly towards east with height That was evident also on pre-eruption and historical data.

It is evident that there was some force present that managed to “deflect” the Holuhraun dyke away from Greip below 10km depth. It is quite likely that there is possible magma accumulation in that area in Greip, which was present before the Holuhraun eruption. That should at least in theory provide some alteration to the surrounding stress fields to possibly deflect the Holuhraun dyke only at that specific area and depth. Looking closely at the plot above, we can see that Greip has two more features. A shallow seismic “cap”, and a gap in seismicity between 5-10km depth. The Holuhraun dyke is also tilted a bit away above 9km depth.

Looking at the SW-NE profiling of Greip, the shallow cap is nicely seen. It is a rather new feature, seen more in the recent year. It is possible that it is a stress field response to the LD2 formation and cooling, or it could be a shallow response to the potential inflation stress of Greip, being more prone to seismicity as a potential extension of the Grimsvotn fissure swarm. Usually it is a combination of many things. On the cross-section, we also see the large seismic gap between 5km and 10km depth. There is currently no valid explanation for that. It is possible that the crust there is cold and dense, so Greip intrusions were not yet able to crack that part of the crust. If this is true, than this is a potential area for higher magnitude earthquakes, perhaps even a star or two, if pressure from below is high enough. The second option is that there is perhaps magma accumulation there, like a magma chamber, which usually does not have much or any earthquakes. If that were the case, that would explain the connected shallow seismic cap. But such a large accumulating body of magma, should also have seismicity surrounding it on the horizontal level as well, as it expands horizontally, not just vertically above and below it. So this is not a favorite option for now, but it remains plausible. There was some seismicity recorded in this layer, but has gone quiet in recent years. Time will eventually show what this area really is.
Also of note on this graphic, is potential sill formation between 18-26km depth.

Speaking of time, I have to include a time plot of Greip, showing its evolution. Some data is of course from the cooling Holuhraun dyke, especially in 2015, but generally it tells the tale. Holuhraun eruption period is removed for obvious reasons. We can see the seismic gap between 5-10km in the recent times. Some of the data in that depth are cooling quakes from LD2.

To put Greip into perspective, I have to finish off with a size comparison between Greip and some central volcanoes. By size, Greip is no pushover, and is in itself strong enough, and likely transporting enough magma, to kick-start many Icelandic volcanoes, were it “used” in that way.

 

Greip is a noisy bugger, which has entered a new type of seismic pattern in the past year, where we see more tremor accompanying the earthquakes, and the elevated shallow sesimicity above its core in the 0-5km depth layer. It will only get more interesting with time, since it is hard to believe that its momentum would stop, given that we are entering (or have entered already) a new plume pulse. Being a 3D plotter, I naturally have to include a 3D spin-around video of Greip, showing 2012-2019 seismicity. You can see the Holuhraun dyke (LD2) passing by it. I recommend watching in HD and full-screen.

Andrej Flis
Down Under (@Recretos)

175 thoughts on “Greip update (June 2019)

  1. Definitely an impressive cluster. It would be nice to establish the dimensions of the 50% or 70.7% ellipsoid. That could roughly establish the size of the potential chamber. (Ellipsoid containing that percentage of quakes)

  2. Excellent post Andrej!

    What to think IF a connection between dyke and Greip was made. Joined forces to Holuhraun eruption or maybe the Holuhraun to be just had been sucked up by Greip?

    • Not sure how to put the term stressfield in the context of the LD2 dyke bending off. Is the exsisting fissure system that gave the dyke an easy pathway a stressfield? I am struggling with the term stressfield. Could someone enlighten me a bit?

      • Can’t help very much. But a stress field as I understand it. Is the tensile or compressive force felt over a region that deviates from the forces felt by that same region in a stable unperturbed state.

        For example. Take a lump of clay and push on it from each side. The body of that lump of clay will feel a compressive forces that acts to deform each grain of clay, causing it to ooze into a new position that removes the stress upon it.

        Do the same thing to a brick and with enough force. The brick will eventually suffer brittle fracture on order to achieve the same result… release of the stress.

        Rock has an inherent resilience to forces acting upon it. Many studies have looked at tensile strength of various types of rock to determine its strength in various stress regimens. One well known characteristic is that rock can withstand far more comprehensive load than it can tensile load. That is why concrete (an artificial rock) is usually reinforced with steel and rebar.

        Now, back to the issue. A mode 1 failure is when rock is pushed apart. This is what is going on when a dike is propagating. The rock is experiencing tensile stress as the finger of magma pushes it’s way through the rock. Once the hydraulic pressure of the magma drops below the tensile strength of the rock, the dike slams shut.

        Where the stress field comes into play, is that it acts to bolster the strength of the rock, making it harder to push through, or easier to push through, depending on the dynamics at play. Usually the overburden pressure (lithostatic pressure) acts to increase the tensile strength of the rock. But changing tectonic stresses can act to lessen or increase the resilience of the rock. This is what happened with Holuhraun as the dike was wandering around prior to eruption.

        I good model of the dynamics of dike propagation can be made with the “hoop strength” formulas to determine if a dike coming out of a chamber can penetrate the host rock. Since lithostatic pressure is lower in shallower part of a chamber or propagating dike. They tend to migrate towards the surface over time because the tensile failure point is lower towards the upper part of the rock.

        Please forgive any typos, this was done on a phone and my coffee hasn’t kicked in yet.

        • The clay example above. Is ductile failure. The brick (also made from clay) is brittle failure.

          • Thank you Lurk, your answer certainly helped. Though I still see some contradictions….

          • Unfortunately, we are not in a classroom setting so I can’t look at you to see where the information falls short. You’re going to have to state where you are getting wheel wrapped in the data.

            Note: I think you did just that in your 20:08. If so, good targeting with your question. 😀

            Meanwhile, here is something that could thoroughly confuse everyone. It’s handy, if you can grit your teeth and study it. Caution, it will take you into the concept of “Pore Pressure.”

            Visualizing Stress and Visualizing Strain.

            And something probably obtuse… but it illustrates some of the complex stress functions going on in a magma chamber environment. From “Caldera formation by magma withdrawal from a reservoir beneath a volcanic edifice” V. Pinel, C. Jaupart / Earth and Planetary Science Letters 230 (2005) 273–287

            “For other shapes, one may rely on three basic principles. One is that a concentrated load acting on a thin roof induces bending, and hence tensile stresses, at the top of the reservoir. A second principle is that a large edifice generates compressive stresses over a large depth range. The third principle is that the hoop stress due to magmatic overpressure depends on the local wall curvature [42]. The chamber shape affects the magnitude of induced stresses. The most
            important parameter is the aspect ratio of the roof region, and one recovers the behaviour of a flat roof by considering a large reservoir.”

            My earlier note about a dike slamming shut when the chamber pressure drops below that needed to keep the pathway open comes from the same reference.

            If anyone wishes to get into the dynamics of caldera formation, that is packed full of models and equations that can keep you quite busy. My main drawback is getting decent cross sections of volcanic terrain. I did have a routine that I could query Google Urts terrain data APIs, but they locked that down so that you can’t easily do that anymore. The only other decent terrain references that exist I can no longer access since I am retired.

            Going completely off the rails, in regards to the North Arch volcanic field mentioned in the last article’s comment chain, you will probably find that it’s location in reference to the island chain of Hawaii is probably related to the same mechanism that seems to dictate the spacing of the Canary Islands… crustal flexure from the mass of the islands. The above Pinel and Jaupart reference can also help you in looking at that from a mathematical point of view. I have a gut feel that something like that could be at play in Iceland in the spacing of central volcanoes and could be why Greip has yet to make a solid appearance.

            (The proximity of the masses of Bárðarbunga and Grímsvötn keeping a lid on Greip until it can get up enough horsepower to punch through.)

          • But this idea does point to Greip’s eventual manifestation possibly being a very energetic event.

          • Yes right the 20.08. 🙂
            The link does work, geolurking, but my tablet won’t eat the downloads, maybe a server isn’t willing to let it, I am travelling a lot these days.
            I’ll try once more in the quiet hours using my laptop. Interesting subject.
            Thanks again.

        • I imagine it as: fill a cake pan with sand pour water in so that the level of the water is even with the sand, if you put a plate on the sand, or your fist and push down, the water will move away from the stress so that you make a little dry ‘island’ in the sand from the pressure

        • Yea these submarine flows are very strange indeed.
          Some of the North Arc submarine flows are almost 200 km long and thick sheets
          High eruptive rates recent submarine flood lavas at – 500 m depth North of Ohau

          The most astonishing is..
          the composition! Its Nephelinite.
          Nephelinite ( 100 to 500 km3 per flow ) flood lavas
          Nephelinites are produced by the smallest ammounts of partial melting in mantle
          It usualy NEVER appears in any large ammounts.
          So large vigorous flows of extremely alkaline lavas are a geological mystery.

          Almost all huge flows on Earth are Thoelitic Basalt made from large ammounts of partial melting.
          Alkaline lavas are a normaly a miniority

          North Arc Flows are a mystery
          Since its Nephelinite its then asks the question if its even related to the mainly thoelite basalt partial melting in Hawaiis hotspot to the south.

          But its likley weakness causes by the plume head and the load of the Islands huge weight causes on the litosphere

          But how souch huge Nephelinite flows can appear I cannot explain

      • If there is a direction of compression or decompression, the dyke will preferentially form in a direction perpendicular to this. So in an area of rifting, it will follow the rift. If Greip is overpressured, the dyke will go around it.

        • But when a central volcano is overpressured it doesn’t take always the easy path of the riftsystem, like Bardarbunga did to jump ‘another’ rift system. I read many caldera type volcanoes have the radial bunch of dykes to relief overpresure and (probably easy) can jump on to a next fissure system. Suppose Greip was over pressured at the time of the Holuhraun event, the radial dyke could have jumped into Greip?

          • Not likely. Suposed that Greip was/is pressurised during the 2014 events, it would cause compression to the crust around it. Meaning that a dyke from Bardarbunga would rather avoid it, than penetrate it. Tho any possible pressure from Greip might not be huge, given that the dyke itself has a strong stress filed alteration and compression of the crust, its very unlikely that the dyke would just ram into Greip. It is a reason that we see a “seismic deflection” of the holuhraun dyke away from the Greip core.

          • But Greip may expand higher temperature areas by taking in more magma. Pressure may build up more and the stressfield will change as well. In this way magma chambers will be able to merge. So the stressfield can be changed after all in a way that makes contact possible. The three chambers of Grimsvötn? Or several chambers within a volcano.
            Well I let it rest, maybe I will understand more of it after some more studying. Not convinced.

    • Bardarbunga has a very well established deep source of magma, that also seismically “lit up” a few years prior to Holuhraun events. I do not believe Greip has much to do with Bardarbunga, based on the current data available, especially steaking magma from Bardarbunga. The LD2 and Greip are not really seismically connected in such a way, tho one could argue that they “touched cheeks, but did not kiss”, which is kinda the emphasis of this post.

      A more detailed petrology study of 2014 Holuhraun lava, publidhet in August 2018, came to this conclusion:
      “The 2014–2015 Holuhraun magma is compositionally indistinguishable from recent basalts erupted from the Bárðarbunga volcanic system, consistent with seismic observations for magma ascent close to the Bárðarbunga central volcano, followed by dyke propagation to the Holuhraun eruption site. Whole-rock elemental and isotopic compositions are remarkably constant throughout the eruption.”

      The source of the 2014 Holuhraun lava is proven many times to be the Bardarbunga central volcano. Petrology, seismic and geodetic studies all point to the same source.

      Greip perhaps had something to do with previous Holuhraun lavas, that is not to be dismissed, but the 2014 events are by now well understood as far as sources go.

      One day when Greip erupts, we will be able to analyse the lava/material, and we will get the final answer where it fits. 🙂

      • Bardarbunga – Holuhraun magmas was also probaly the hottest lavas ever seem by cameras in Iceland. Holuhraun was 1185 C to 1195 C
        Making it the hottest Icelandic eruption filmed so far.

        • Well, first, we are not in Hawaii, tho some examples might be similar in some way, or collapses. 🙂 You do have to realize that there are not two volcanoes in Iceland that have exactly the same or even “indistinguishable” magma composition as the Holuhraun was from other Bardarbunga central sourced basalt eruptions.
          Magma might come from the same source 80-400km below Iceland. But before it gets to the surface, it has to rise through the crust, one way or the other, through many different layers, where its compoaition changes in a unique way.
          Holuhraun magma/lava was said to have a rather low residence time in the crust, meaning it was rather fresh/primitive. This basically points to Bardarbunga rather than Greip actually. Why? Because to have low crust residence time, means it had to have a rather quick ascent. And for that, you need a well established magma plumbing system, rather old and likely semi-open at very depths to moho. That actually fits Bardarbunga nicely in all points. Greip on the other hand is a dyke swarm, composed of individual dykes, and likely also sills. Considering it is a rather new feature (geologically speaking), just a few decades or centuries old, you will not only have more time in the crust, but also more crustal assimilates in the magma composition. Basically there is extremely low probability that magma in Greip core would be indistinguishable from the Bardarbunga plumbing system basalts. In a dyke swarm, it starts to change composition already in the long time in the dykes, before even getting to any proper “chamber-type” accumulation volume. And even if it would just partially feed Holuhraun, there would still be an impact on the composition and would leave its fingerprint. 😉

          • Holuhraun magmas where also good proof of the Hotspot under Iceland. 2014 s magmas where quite similar to kilaueas 2018
            in composition.
            Holuhraun was extremely gas rich and strongly thoelitic in basaltic composition. One of the hottest Icelandic eruptions ever seen by cameras
            Holuhraun was a melt from very high levels of partial melting In the mantle.
            Holuhraun acended from great depths but is worth to remeber that 80 km down in Iceland the temperature in Vatnajökull is close to 1510 C so Holuhraun magmas cooled to 1188 C on the way up as it ascended through the thick 46 ( 50 ) km thick Icelandic intrusive and partly flood basalt formed Igenous plateau crust.
            Grimsvötn 2011 was also strongly thoelitic and primitive and fresh from great depths

          • Holuhrauns very hot arriving magmas where also mixed with still very very hot basalt magma that was residing inside Bardarbunga
            As the dyke broke into the resovair inside Bardarbunga and filling it to overpressurize and later the dyke broke out channeling the magma towards the Holuhraun desert.

            Now 5 years after the show
            The caldera roof plug have finaly settled and stopped making these mag 3 and higher quakes.
            I expect Bardarbunga to stay quiet for a long time now.
            Any more seismcity woud be either mid ocean ridge interacting with it
            Or magma refilling the drained under resovairs
            Holuhraun was 1,4km3 Im supprised it did not became much larger. Bardarbunga Rifting lava floods tends to get quite large
            Anything from 4 km3 to 30 km3
            Large but also very infrequent shows

  3. 3D fly through! Great stuff. The size comparison of Greip to Iceland’s other prominent volcanoes is very interesting. Many thanks for this, Andrej.
    Take care, now.

  4. Is there any feature in the bedrock surface below the icecap, at Greip?

    • Based on what was available, its hard to tell. No clear indication. But if you can somehow manage to get me the data that was used for this image in a gridded format, I can do some high resolution modelling. 🙂

    • It doesnt look like it, only what looks like a flat area next to a lake. Maybe if holuhraun happened 100 years in the future it woukd have been a bit more explosive, being that a lake exists above where it intruded so more groundwater?

      Very interesting rendering.

        • Next to kverkfjoll, its not right on top of greip. There is no structure above where greip is right now so probably there hasnt been an eruption there recently.

      • Note that the lake shows what would be there without the ice. It does not mean there is currently a lake: just that the area is depressed.

    • Where did that picture come from too, is there an overhead view or interactive map of it? 🙂

      • It is from Helgi Björnsson, his book “The Glaciers of Iceland: A Historical, Cultural and Scientific Overview. ” The version I have is the 2017 english translation. This figure appears in it; it refers to
        Björnsson 1986a, Surface and bedrock topography of ice caps in Iceland mapped by radio echo soundings. Annals of Glaciology, 8, 11–18;
        -, 1988, Hydrology of ice caps in volcanic regions. Rit Vísindafélag Íslands, 45;
        -, 1996, Scales and rates of glacial sediment removal: A 20 km long and 300 m deep trench created beneath Breiðamerkurjökull during the Little Ice Age. Annals of Glaciology, 22, 141–146.

    • I found little evidence of a feature when I wrote the first Greip article back in 2017, I had found some older topological maps from the 90’s (I think).

  5. This is hilarious…It’s too much

    It is also the worst pseudo-science ‘news’paper in the UK and we prefer not to add to their click bait. Link removed – admin.

    • why do you humor these guys they write obviously titillating garbage, if I see Express UK I ignore it. My mother used to tell us kids when we got hurt “Oh, you’ll live through that and die of something else” which is true until that final thing get’s ya, but seriously, although I suppose one of those could get us, it does not need a daily scare fest, it serves no purpose.

  6. Another topic related question (yeah, hold on 😉😈).
    It is about the plot “earthquake magnitude, distribution by depth”.
    There are many series of three, four or five dots aligned near to another. How could those be explained?

    They look quite like the small aligned earthquake series that took place in the magma chamber under Kilauea whilst its recent collapse, plotted in the USGS website.
    https://volcanoes.usgs.gov/observatories/hvo/hvo_earthquakes.html
    But that was a flat position graph….

    • Kilauea experiences only relativly shallow quakes
      Since the volcanos interior is so very very very hot and ductile. Kilauea is the volcano with highest heat loss when it comes to geologic heat given off to the atmosphere

    • Well, as the text just next to the plot nicely explains: “. This plot does not show any actual shape of Greip, but only presents earthquake magnitude distribution by depth.”

      The plot shows magnitude versus depth for earthquakes. So when you have 1000 quakes, its not hard to get three or four quakes of similar depth and magnitude. But its not an actual shape of greip, since this does not include any horizontal data.

        • It is not a coincidence. That is just the data distribution. I interpreted the basics of this plot, and what it shows, and I emphasised that this doesnt show any shape of Greip because it does not contain any horizontal data. Its a plot that shows only 1 actual spatial dimension (z) of a 3 dimensional field. So you cant derive any shapes from this plot.

  7. Just in time for the article, Greip got hot again. A dyke intrusion with a tremor episode, that was felt all the way up to Herdubreid. 5 earthquakes were recorded out of it, no stronger than M0.7. Most of the energy was in the tremor, not in the earthquakes, which is the “new” norm for Greip. The total energy of individual quakes is below M1, but the acompanying total tremor energy can exceed an M2 equivalent.

    • What’s the big green one? I’m just eyeballing it but it looks bigger than an 0.7 to me …

      • Check the timing, look for it in the quake list, find this M1.3:

        Saturday
        08.06.2019 13:57:37 64.452 -17.343 4.0 km 1.3 99.0 6.3 km NNW of Grímsfjall

      • Meanwhile in Hawaii…

        Hotspot Wars: Episode III

        -Kilauea: I AM HAWAII

        -Mauna Loa: NOT YET

        -Kilauea: Its treason then

        Lavasaber duel, Mauna Kea, Haleakala and Hualalai get lava-stabbed. We will have to wait several tens of thousands of years to know who wins, okno we all know, Kilauea will. But there is a Loihi lurking in the shadows (or in the waters, or maybe in Tatooine).

        Waffle, Admin

        • I’m rather curious what the eruption rate from Haleakala is, not all that easy to find a whole lot of info on it online

          • I don’t think there is any estimate, but it would be small compared to Mauna Loa or Kilauea.

            A hawaiian volcano erupts almost all of its volume during its shield stage then it goes extinct or transitions into another stage of lower, less frequent activity, the postshield. Haleakala had its shield stage between ~1.9 to 1.2 million years ago during which it built a massive edifice, maybe the largest in Hawaii. Haleakala has remained active since then, making it the longest postshield stage of any hawaiian volcano but activity has declined a lot, if I have to guess then currently the eruption rates might be somewhere around 0.001-0.002 km³/year.

            Activity at Haleakala seems to come in pulses, its last eruptions were in ~1350 and ~1550, but between 800 and 1100 it had around 10 eruptions following a period of low activity.

    • East African volcanism? well I guess that depends on what exactly are you looking for, on Afar you won’t find much, that is uncharted territory, but there are publications of 21st century eruptions that have been studied through remote sensing, Manda Hararo 2005-2010 is an interesting event. In southern Ethiopia (the Main Ethiopian Rift) there are a series of large Pleistocene calderas, at least one of them Awassa has had a VEI 8. There is the Kenya Rift with many volcanoes such as Emuruangogolak, Menengai, Logngonot or Suswa. Then there is Ol Doinyo Lengai in Tanzania for which I imagine there must be a lot of info given its uniqueness. Then there is the Virunga Volcanic Province with the 2 hyperactive volcanoes, Nyiragongo and Nyamuragira, http://www.virunga-volcanoes.org/

      There are some posts of VolcanoCafe centered on the EARS:
      https://www.volcanocafe.org/rungwe/
      ttps://www.volcanocafe.org/turkana-and-the-dawn-of-man/

      • I was thinking Volcano observatorys and other monitoring organisations. To keep up with whats going on. I’we got family from/in the region and therefore it’s a little extra interesting.

        The countries are poor, so i understand monitoring is not up there with Iceland or the US.

        • The Virunga Volcanoes page I linked might be the closest thing to what you describe, but still it doesn’t provide much real-time monitoring and the monthly reports are not avaliable.

        • Valid points. But VAAC are typically via pilot reporting or satellite monitoring. In that regard, I would have more faith in a VAAC report since their job is to protect and warn flights… keeping in mind that they may over estimate things just to err on the side of safety.

          • I think the 55,000 ft just means the top of the air space and tells flights that they should not attempt to fly above it but have to go around. It doesn’t mean ash was actually as high as that. I think.

  8. What fascinates me, is despite all the talk and information (many times uncalled for) about Hawaii in every comment section under every article, there were only 2 or 3 articles written on Hawaii here at VC, since the 2014 Holuhraun eruption, despite the recent activity and even an eruption. To me, that speaks volumes, and shows the realistic fascination/excitement level that Hawaii is able to produce. In that aspect it seems to have a hard time even getting close to the scale of the small 2010 Eyjafjallajokull eruption. I truly respect all volcanoes and would like to see diverse article content here at VC. So this is a call to all the Hawaii fans here at VC, that give out huge amout of information and numbers on Hawaii and like to talk the talk. A call for you to put your money where your keyboards are, and start to walk the walk and write articles about it. The more diverse the content here, the better. 🙂

    • Yea its probaly my Hawaii entusiasm thats too large
      For now I will be silent about Hawaii

      But trust me: Hawaii is very very very underestimated
      When it have Done One of the largest lava fountains ever photographed year 1959, 1961, 1969, 1983 – 1986 and 2018 some of these older fountains been 600 m tall.
      And Kilauea haves an absoutley insane magma supply
      Capable of doing km3 sized bleeds both fast and slow ones every 10 years
      Kapoho 1961 ( 1km3 ) Mauna Ulu 1969 – 1974 ( 1,2km3 ) Puu Oo 1983 – 2018 ( 8km3 ) and Leilani – Puna ( 1,1km3 ). Extremely vigorous magma supply

      But now no more Hawaii talk from me 🙂

      • Hehe, well, I would like to see your talk and all that knowledge and information from you, Turtle , and others, focused in an article where it can really shine in the spotlight. 🙂

        • Andrej Flis
          I think Grimsvötn is making itself ready for a New eruption
          The mountain been getting more seismicaly active
          The upper sourthen magma chamber in Grimsvötn is growing causing shallow quakes: Its open hot conduit and lacks deeper earthquakes.
          The next eruption will likley be repeat of 2004

      • Waffle removed by Admin. It is glorious somehow to succeed with waffling as an answer to a comment by an Admin warning about the foibles of waffling. But, good things are coming down below.


    • Waffle removed by Admin. Warning handed out for waffling.

    • Activity Loihi vicinity continues

      2.8 51km SSE of Pahala, Hawaii 2019-06-10 10:59:32 (UTC) 9.7 km
      2.4 50km SSE of Pahala, Hawaii 2019-06-10 06:37:37 (UTC) 8.0 km
      2.3 53km SSE of Pahala, Hawaii 2019-06-09 14:49:08 (UTC) 8.7 km
      2.4 50km SSE of Pahala, Hawaii 2019-06-08 08:41:05 (UTC) 11.7 km
      2.2 47km SSE of Pahala, Hawaii 2019-06-08 06:26:48 (UTC) 9.1 km
      2.2 51km SSE of Pahala, Hawaii 2019-06-08 05:51:14 (UTC) 8.0 km
      2.5 46km SE of Pahala, Hawaii 2019-06-06 23:40:02 (UTC) 10.3 km
      1.7 47km SE of Pahala, Hawaii 2019-06-06 08:23:16 (UTC) 9.6 km

  9. Grimsvötn starts to look uneasy/ restless/fertile/ happy/ charged up/ again for an eruption
    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 e

    • No worries Jesper. As pointed out here before, Grimsvotn is following the model quite closely and that suggests an eruption is at least 12 months away. Unless it does a Carl and a sudden earthquake doubles the stress. Not impossible.

      • Seems that a Grimsvotn eruption will happen sometime in 2020 (between Jan and Dec 2020) with perhaps a 80-90℅ probability.

        Ohhh thanks to maths I might just be able to boldly and accurately forecast an eruption one year in advance!

        Fingers crossed. I like that curve (cumulative seismic release). I find Grimsvotn to be one of the easiest volcanoes to predict, unlike Katla or Hekla!

        • Correction, Grimsvotn actually looks more likely to erupt sometime betwern Jul 2020 and Dec 2020. So I am narrowing my forecast even more…

          • I would include early 2021 and reduce the likelihood a bit. Otherwise I agree

      • I have a question regarding this plot. In 2004 a cumulative seismic moment of 4 was reached, in 2011 the eruption started at a cumulative seismic moment of 3.

        Your current calculation/prediction is also based on a value of 3. if Grimsvötn sticks to that, no problem. But what if a cumulative seismic moment of 2.6 or 2-5 is enough to set it off?

        • It hasn’t in the past, at least for the two eruptions we have data for. Towards the end the moment increases very fast so there is not too much difference between a ‘3’ eruption or waiting for a ‘4’. An eruption at lower moment could be quit a bit earlier. But that is the joy of model predictions: if you get it wrong it gives a clue where the error lies.

          • Also, and this is very important, Grimsvotn usually erupts every 2-7 years, often during hotspot maxima, but also has periods of dormancy like between 1938 and 1983. It would have been great to have the cucumulative seismic release data for that period!

  10. Greip idea: if you look at the spacing of volcanoes along to the two delineations, they are fairly constant. Along the same rift, they are separated by about 28 km or so. That counts for Hamarinn-Bardarbunga-Kistufell and for Grimsvotn- Thordarnhyrna. (There are more eruption centres there which I assume are rift fed and not separate volcanoes.) The two lines are themselves also separated by about 25 km. That separation probably not accidental, but may represent the area over which a single conduit can suck up magma. In fact, to the west, Tungnafell is about the same distance from Bardarbunga.

    But Grimsvotn and Kverkfjol are too far apart. There is room for a separate volcano in between. Greip?

    https://i2.wp.com/www.volcanocafe.org/wp-content/uploads/2018/11/word-image-10.jpeg

    • I found this very interesting. What do you exactly mean by “That separation probably not accidental, but may represent the area over which a single conduit can suck up magma”?

      • I’d read that as an implication about the underside of the crust – and what is the largest area which can withstand upwelling magma without fracturing and allowing magma through in a new spot. If the area is about 25km x 25km then as soon as you get to 50km between two volcanoes you get a fresh crack appear between them. Dunno if I’ve got that right – but it feels like it might make sense (even if my example number may be wrong).

        • Yes. Imagine you are a dollop of magma, 30 km below ground, trying to find a way to the surface. If there is a conduit nearby, you will probably take that (the easy) route. If the conduit is too far away, it becomes easier to burn a new one. This process works for volcanoes: look at Hawaii. If you have a hotspot underneath a moving plate, you may expect it to burn a line through it. But it doesn’t happen. Instead it burns a hole (also known as a ‘volcano’) and channels the heat through that. Until the hole has moved away too far, and the hotspot burns a new one. So you get a sequence of volcanoes, rather than a long rift.

          In Hawaii the heat is deep, and therefore the volcanoes are a bit further apart. In Vatnajokull (speculation alert) the magma is closer to the surface and the holes form closer together.

          How does it sound: convincing/plausible/far-fetched?

          • In Iceland the plates move West and East. Iceland Hotspot is situated right over the spreading boundary and Burns volcanoes west and east.

            As long as Icelands Hotspot and Mid Atlantic Ridge are lined up togther like this, Iceland will be the fastest growing island in the Atlantic.

          • That sounds eminently reasonable and is indeed a good argument.

            Those damned volcanoes, though ….

        • I have seen it said as at least a plausible speculation that, at least for subduction volcanoes, the spacing between them is approximately equal to the thickness of (brittle) crust in that area

    • Reuinion is erupting again and quite large
      That island is tiny compared to Iceland
      Albert how many times higher in the magma feed in Iceland compared to Reunion

    • That chart is kind of neat – it keeps updating itself.

    • Storm Watching with high levels of rainfall in southern UK (not very serious, really). It’s my other hobby, there being no handy volcanoes in Surrey (yet).

    • Working and done a beach cleanup, found a piece of pumice floating in the water, most likely it has been broken off a cliff somewhere in the area, would be nice to know where though. Otherwise, nearest volcano activity is Iceland, and I don’t remember any recent pumice creating episode there recently.

      • Coud be a evolved submarine eruption that happened in the ridge from an old stale gassy magma pocket
        Even if most ridge activity is effusive and thoelitic basaltic and produce pillow and sheet lavas

  11. Agung just erupting again tonight.
    Wed, 12 Jun 2019 18:06Agung (INDONESIA): DISCRETE ERUPTION TO AS HIGH AS FL300 OBS VA DTG: 12/1806Z (Darwin VAAC)
    Wed, 12 Jun 2019 18:30Agung (INDONESIA): DISCRETE ERUPTION TO FL300 OBS MOV SW 25KT OBS VA DTG: 12/1830Z (Darwin VAAC)
    Wed, 12 Jun 2019 19:19Agung (INDONESIA): DISCRETE ERUPTION TO FL300 OBS MOV SW 25KT OBS VA DTG: 12/1920Z (Darwin VAAC)
    ​Wed, 12 Jun 2019 20:13Agung (INDONESIA): DISCRETE VA TO FL300 MOV SW 25KT. VA TO FL180 MOV W 15KT. (Darwin VAAC)

    • And for those of you playing the home game. The plume height from this graph is the height ABOVE the edifice. Mass ejection rate is in DRE m³/s. VAAC Heights are in Hundreds of feet. FL300 ≈ 30000 feet.

      • Hmmm, 30,000 feet seems a reasonable size eruption, or am I wrong? Looking at the video it seemed to eject a fair amount of lava as well as ash. Sorry I lost the link.

        • Sizable? Yes. But not likely to reach the topopause at it’s location. This means that it’s affect on the aerosol layer is minimal at best. It never made the stratosphere. The only way it’s SO2 can reach that is via diffusion during the normal course of atmospheric circulation… and the longer it’s SO2 remains in the troposphere, the quicker it’s SO2 becomes sulfate before ever contributing to the aerosol concentration. Normal weather will leach it out long before it’s a global problem.

          The direct injections to the Stratosphere is where it really becomes problematic. This is why the Kamchatka and Icelandic volcanoes are the worrisome critters. {But even with that, the SO2 and Sulfate has to climb a pretty steep “hill” to get up on top of the Hadley cells over the tropics to have much of an effect.}

          • Note, the tropopause as represented in these plots is based on the 200mb elevations. The actual tropopause is where the lapse rate changes from negative to positive. This is typically around 200mb, but it is not a hard fast rule.

            {Side note: In the troposphere, with higher elevation temperature decreases. In the stratosphere, with higher elevation, temperature increases.}

            In other words, my plots are an approximation.

            “Your mileage may vary”, “Objects in mirror may be closer than they appear”… etc.

            If any actual meteorologists wish to chime in, it would be welcome. {I generally just play in the rain.}

        • Seems like there are two likely directions that this current eruption on agung can go. The first is an escalation to a bigger eruption, the second is a long lives series of vulcanian eruptions like what happens at sakurajima. The first option seems the more likely one though, given the location, but it probably also wont be a massive plinian eruption either, VEI 4 is most likely for now.

          Eruptions at batur have produced extensive lava flows in the caldera there though so maybe the activity at agung might do that.

          It would be interesting to find out what the youngest volcano in indonesia is, many of the well known volcanoes staryed out as basalt volcanoes that were often shields but later became more andesitic stratovolcanoes and later still calderas, anak krakatau is the youngest cone but it is growing in an older volcano, which already went through that whole lifecycle at least one other time.
          Last time I checked there are no dominantly basalt volcanoes in indonesia, they all seem to be somewhat evolved.

          • I am not saying that a cataclysmic VEI 7 or anything like that is likely with Agung. But this volcano is only recently active as it’s first recorded eruption in the holocene was in 1808. I think a larger eruption(VEI5+) could be on the cards with a volcano like this.

          • 1808 was not its first holocene eruption, it is way too smooth and symmetrical for that. Its lava is also pretty mafic for a subduction volcano, 1968 was andesite but the new stuff might be more basaltic andesite if it was dormant for 10000 years it would be rhyolite and a lot more obvious.
            The volcanoes here dont seem to do VEI 7s from being dormant a long time but more from becoming too big for the crust above their magma chambers to support them. Tambora was trachyandesite, which is a lot less evolved than a typical eruption product from something that big. All the volcanoes here are enormous by world standards, nearly as big as kilimanjaro, and about twice as big as most volcanoes in similar settings. Tambora was over 4300 meters tall before 1815, making it the second tallest island on earth after papua new guinea, and the tallest volcanic island on earth, 100 meters taller than hawaii which is the record now. In the ice age they all would have been extensively glaciated and tambora almost certainly got snow in historic times.

          • And Mount Kenya
            Was a real behemoth of a continetal rift volcano when it was at its peak in Early pleistocene

            Todays eroded very alkaline evolved volcanic massive is around 5 km tall and almost 70 km wide. Kilimanjaro is similarly Big but much more active and less eroded.
            Mount Kenya been estimated to been 7,2 km ( 7200 m ) tall when it was at its peak and covered by a thick icesheet down to 2800 m in pleistocene. Kilimanjaro may been at similar height when it was at its peak of activity )
            Enormous size for not being an ocean Island shield. Mount Kenya seems to have been mostly gentle dome building and blocky flow activity it became inactive in late pleistocene and covered by an enormous Vatnajökull like icecap

            Kilimanjaro and Mount Kenya are isolated hyperdiverse rainy Islands is a hot sea of Savannah Grass. They makes their own weather and climate zones

            Very very large volcanoes knowing they are so extremely alkaline in magma composition ( very small ammounts of partial melting makes these magmas ) souch alkalinity
            usualy dont make any large volcanoes.
            Mount Kenya and Kilimanjaro are Phonolites – Tephriphonolites, Tephrites, Trachytes
            Sillica rich alkaline magmas
            But that arera of Africa is well known for extreme alkalinity.

            Kilimanjaro is still active and Mount Kenya likley too ( Kilimanjaro haves hot sulfur fumaroles on the summit and its inner ash pit formed by vulcanian eruptions looks very very Young ) Kilimanjaro is alive and will erupt later.

            Mount Kenya is much much less active
            But it have some Young looking coulees and domes / blocky flows on its flanks thats likley just a few 1000 s if not a few 100 s of years old knowing how much it rains there.

            These are very large volcanoes
            But they are very small compared to Hawaiis deep sea Giants

          • Mount Elgon in Uganda
            Is a similar continetal rift – hotspot alkaline
            Giant eroded Stratovolcano
            Its 85 km wide and around 5 km high.
            Its too likley reached above 7 km when it was at its best prime days
            Its badely eroded but a 11 km wide caldera is still clearly visible. And that was indeed an explosive mazama type caldera. Either a very large VEI 6 or most likley a Major VEI 7 knowing its great depth when its already eroded and filled in ( 400 km3 ? for Elgons last large collapse eruption? )
            Kilimanjaro, Mount Kenya, Mount Elgon are all complex alkaline stratovolcanoes
            They are absoutley enormously huge compared to the ” normal sized ” stratovolcanoes in US west coast and Andes and everywhere else whatever.

            The African Stratovolcanoes are very Big indeed Cameroon, Mount Kenya, Kilimanjaro, Mount Elgon. Its supprising how very alkaline they are ( small ammounts of partial melting deep down ) Yet they grow so enormously huge. Strongly alkaline systems tends to be very small infact .. most alkaline volcanoes are monogentic fields and cones, Not like these enormous Giants of continetal Africa

      • duration of eruption would also make a difference, yes?

    • Seismo TMKS indicates, there is a supply of new magma from depth

  12. Guys, I really like this blog because in addition to the high quality articles it is a great source of information of what’s going on in the wicked world of volcanoes. I also appreciate the updates about Hawaii – it is an interesting place and we all know that it is just a matter of time until something happens again.

    Although I can only speak for myself, I have two kind requests:

    Can we please treat Hawaii like Iceland, the Canary Islands or any other place in the world? When something happens, comments and discussions are welcome. But if all is quiet on Hawaii and nothing to report, we should focus our attention to other places.

    And please stop the hype about lava flows and what some volcanoes are capable of. I really can’t hear the words „huge lava flows“, „worlds largest erupter“ or „largest magma supply in the world“ any more. This can be part of an article to put things into context but I don’t like to read the same comments all over again over a period of several weeks.

    Volcanoes are fascinating but they are not part of a TV competition show.

    Thank you, gentlemen.

    • Long time lurker signing in to second this. It’s a real bore wading through screeds of whatiffery regarding the likely size and extent of certain volcanoes next eruptions. I thought the dragons had got on top of this but it’s starting again. I know you are enthusiastic (three posters; you know who you are) but your obsessive postings are overwhelming this place. Dragons – weren’t you going to set up a separate area for their musings? Please?

      • Dirk, yes that was the plan. We’ve all been too busy to action and test it. It will be done as soon as possible.

        • The unsung heroes in all this are the admins fighting the back end of WP trying to make it bend to our will.

          Me, I’m just sitting around waiting for orders from high command and trying to get a few super hot specialty cultivars of peppers to germinate. If I succeed I’ll have 4 of the hottest varieties of peppers on Earth growing.

    • er… ah,,,, not to split hairs, but aren’t there also female dragons? and the last time i looked, i was female (i know it’s been a long time 😉 ) OH, it just occured to me that that is a signature and refering to themselves… They are the gentlemen in the signature… nevermind (in my best rosanna rosanna danna voice) Best! from raving motsfo suffering from a fever and a migraine…uggghh.

      There are indeed female Dragons, they bite far worse than the male Dragons.

      • There is indeed, although not currently active (dormant). There are others, but not with access to the admin hammer of comment squishing.

        Gaz is confused, there is currently one active Dragon of the female persuasion, and one that is retired (for now). There is also the Eternal Dragon in the Sky (Sissel)

        • Why is it “female persuasion?”

          Do they have to be convinced of something? Most that I encounter already have their minds made up and convincing them otherwise is near impossible. (Wife is an ESTJ)

    • I have to agree, its also rather boring and tedious after the 20th time. Many posters have so many other interesting things to say and the threads always seem to have someone butting in with an Hawaii quote that isn’t relevant or interesting.

      • I second this….I have started to scroll by these posts, but I find it tedious. Also please stop hijacking posts about other topics and turning it into hawaii-o-rama.

        • It’s been noted and it will be actioned as soon as one of us (non-gender specific) dragons finds the time to sort it all out. Please have patience while we tidy things up.

    • I coincide in that such things as: constant volcanic competition, spamming and fake data are a problem needing to be improved, and from my view these have been occurring recently, and often in relation to Hawaii.

      Stating that one volcano is better than another is always going to bother someone because everyone has its favourite volcano/volcanoes and it is also pointless since there is not a way to decide which volcano is better. It is also pointless to say which volcano has the largest volcanic edifice or the highest supply rate given that there is not a person to have gone through every single one to find out the values and there are many ways to approach this question.

      Spamming won’t add any new information so I think it is obvious that if someone has read 5 times virtually the same exact comment it is going to find it boring.

      Fake information is out of place in a scientific blog such as this, people should try to be well informed if they are about to make an statement of some sort.

      I however must say that not everyone finds the same things interesting, and that no one is to decide what is or what is not interesting in general. Some of my comments about Hawaii volcanic activity have been aimed for certain people and I am aware that maybe others won’t have the information to understand or the interest to read the comment but if two or more people want to discuss what happened at a hawaiian volcano in the past, a comparison to the present situation, or similar stuff… I don’t see where the problem lies as long as it is kept to one thread without flooding the entire chat. Also, the separate chat for Hawaii seems a horrible idea to me.

      Currently even though there aren’t any currently ongoing nor imminent eruptions seemingly coming nor behaviours drastically changed for any volcanoes of neither Hawaii nor Iceland, these are still dominating the chat (lately together with Sunda, but this one well deserved). The same way Iceland triggers admiration, particularly among many long-time lurkers, to others Hawaii does. Some moderation seems however necessary for the first aspects I mentioned.

      • It will be a separate comment chat for everything OT, not just Hawaii. It’ll be a place where theories can be bashed out and refined to then appear on the main blog comment section or an article.

    • I was going to write a detailed comment but i think what i will say is that i agree broadly with many of the comments below. The volcanic one up manship, what ifs, possible entrenchment has perhaps stiffled this fine blog to a degree.

    • Its been calm for a while so i guess the dragons are a bit restless for a new bath.

      Perhaps its a idea to start a forum or discord for more general discussion. Or stick a article in the navbar at the top to give general iceland and hawaii discussions their own place?

      • I second that last idea, this place is probably just way too big to have only one comment section now. The average article since kilauea erupted has gotten about 200 comments, before it was half that and mostly still holding onto iceland after holuhraun. Before holuhraun it was more around 200 comments still but most comments then were single sentences and often general discussion about nothing volcanic.
        What this says is that generally people have a lot more to say now (not just me and jesper 🙂 ) and also that most people here arrived either from holuhraun or kilauea and might be generally disinterested in stuff elsewhere. Only a very rough observation but still notable.

        Something else that might help is a 100 word max for comments, or something like that, allows discussion but not comments that could be entire articles.

        • I was lurking for years before I actually said something. Just because someone only recently started commenting, doesn’t mean they haven’t been reading.

          Too much focus on Iceland and Hawaii is not good either. Both are very well-studied and well-monitored. Which locations have potentially dangerous or dramatic volcanoes that are not well-studied?

          South America? East Africa? West Africa? Philippines? Galapagos Islands? Is there a volcano under Lake Victoria? If not why is there a giant depression in the middle of a rift zone?

  13. Kilimanjaro is not dead at all
    There are hot sulfurious vents in the summit
    Thats a very strong sign there is active magma inside the mountain
    The summit ashpit also looks very very Young

  14. My personal theory about the state of Agung: I think the eruption in November 2017 was a half-dud. As I remember, there were two distinct plumes: One of ash and one of almost exclusively gas/water vapour. I think that because of that, the magma lost too much volatiles to keep up the eruption and turned “stale”. This would explain the infrequent short explosions which happen every time the (low) gas pressure-build up over time overcomes the weight of the pancake-like lava covering the crater.
    IF Agung now had a influx of fresh magma rich in volatiles it might get interesting.
    So, people who know way more about volcanoes than me: would this scenario be plausible?

      • Yes, that is a good paper. It shows the interferometric data indicating where Agung’s magma intrusion was at…. between Batur and Agung.

        • Squeezing up between two edifices. Agung and Batur are very close together so it is quite something to try to squeeze another volcano in there. Maybe that’s why the new magma chamber decided to use the Agung plumbing.

          • But why not Batur? A sizable chunk of it went bye-bye some time ago.

          • Lurking: good question. I am also wondering why two eruptions or so ago Agung spit up unusually pale ash. Top of the mountain keeps changing colors. (Agung webcam is my screen saver/work break view).

      • Thank you for posting those two papers! Very informative.

  15. Etna is showing signs of activity in its voragine crater, which is the same one that erupted in 2015 and 2016 in spectacular fashion and made the 2 km tall lava fountain in 1999, it is generally much more violent and explosive in its eruptive activity than the southeast crater complex which is mostly effusive. Interesting how one volcano can erupt so many different ways in such a small area.

    Also I read the comments, a fair point was made which is why I havent gone on here at all in the last 3 days (not sure who the 3rd person is but I know you are talking about me and jesper), but in saying that I havent actually seen anyone else even try to start a discussion over another volcano that is not directly on topic with the article (which in this particular case you cant really ask many questions, we dont know the necessary information), most of the time a non-article comment is made it is a talk about something completely random and locally personal to the commenter that often has nothing to do with volcanoes at all. Im not in any position of authority here so this doesnt really matter but I would like to at least bring this up, it has equally been bugging me as much as my hawaii discussion appears to bother others, and I know this same topic has been brought up before too.

    A more important question we should all be asking is why none of the admins at all have commented in the last week…

    Rest assured that we are keeping an eye on things. Always.

    • Well that last paragraph didnt age well… 🙂

      Good of you to notice

    • Turtle, I don’t think anyone wants to forbid OT posts. Everything else would be ridiculous. The point is that the constant flow of posts of huuge this bigger that better this, which are almost to the letter identical to previous posts gets tiresome. I personally have nothing against going OT (as long as it stays vaguely volcanism / geoscience-related) in principle.

    • “A more important question we should all be asking is why none of the admins at all have commented in the last week…”

      Why is it a more important question?
      We do all have lives, very busy at times, and there will be periods of quite from us.

    • 14/06/2019 – 13/06/2019 = 1 day.

      Now, if you really want, I can post images of my germinating ultra-hot pepper seeds, but I think most are here for volcano info and not plants.

  16. Personally, I rather enjoy the off topic discussions, especially when volcanic news is a little thin. They often provide an insight into the personalities of the site’s contributors, which can be as interesting as any volcano.

    However, the long, topic repetitive monologues can become tedious, even if the enthusiasm and erudition behind them is obvious. Maybe remember that trick to good writing is to consider what the readers will enjoy; otherwise, to borrow a colloquialism, you are just farting because you like the smell of your own shit.

    As the volcanic news is a little thin, I would like to point out the Sun newspaper’s scientifically substantial article on the imminent destruction of Melbourne by a massive volcanic eruption and the prospect of lava running down Bourke Street. Tsk. Why has the city not yet been evacuated?

    https://www.thesun.co.uk/news/9272194/volcano-alert-australia-melbourne-lava-streets/

    And here is an opportunity I am surprised the British tabloids have not yet made a meal of: the large lump of metal on the moon bigger than Hawaii’s Big Island. What could it be other than a giant alien space ship that crashed into the moon in a failed invasion of Earth?

    https://www.mnn.com/earth-matters/space/stories/moon-mass-crater-dark-side

      • Its resedues
        The vaporized remains of the Asteorid
        The speed is so insane it vaporizes
        Asteorid impacts are hotter than surface of the sun

      • OT in reponce to OT.

        South Pole-Aitken Basin is supposed by some to be one of the causative effects for the Lunar mare that we see as the dark splotches on the visible side of the Moon. One idea that I saw discussed on the SciChannel is that the impactor that made the South Pole-Aitken Basin caused severe fracturing in the Lunar crust on the visible side, and that subsequent impacts released the molten material as flood basalt. To demonstrate this, they had someone at JPL run a test with a high energy impactor in a glass (actually probably lucite) ball in a vacuum using a high energy cannon.

        The result was that the antipodal shock wave focused on the far side and began rupturing the material from within before it reached the surface. The test impact came in from the lower right corner of the image.

        The only real relationship this has to our setting, is the occasionally discussed anti-podal hot spot idea.

        The residual large mass detected in the South Pole-Aitken Basin supports the idea that it is likely just a residual core fragment from a planetismal. The inner solar system was a literal shooting gallery for quite some time after the accretion disk started forming planets.

        Additionally, this is not that difference than the discovery of a large gravity anomaly that lead to the discover of Wilkes Land impact crater. Of note, is that purportedly, it was antipodal to the Siberian Traps that formed at about the same time. {250 million years ago} and in some ideas (mine), the 65 myr old Chixilub impactor may have ramped up the intensity of the ongoing Deccan Traps though they were probably not in direct alignment with the antipodal position at the time.

        • Sounds credible. Would you expect to see some evidence of the bulk of such a planetismal on the surface after all this time?

          • That might be what they are reporting on. In high energy impacts, the crater is usually of a complex type where the debris and melt-pool fill in the excavated crater… along with rim-wall collapse.

            Something caused the late heavy bombardment, this might just be a shard from that event.

            (The Grand Tack might be related… as is the Jumping Jupiter idea)

            One thing that intrigues me, is that from what I understand, in the various scenarios, a fifth heavy planet seems to be one of the more sane model runs, with the lightest of them loosing out and being ejected from the solar system. This could account for the yet to be sighted “super Earth” that is proposed to account for oddities in the orbit of some Kuiper belt objects.

            The way I understand it, the researchers claiming it’s existence first started off trying to disprove something else was out there. After they found the strange orbits, the mathematical models that accounted for a large perturber doing this also predicted a second set of strange orbits on a diametrically opposite side from them, and they ran across objects that fit that also.

    • You should have read The Independent’s article, by its resident Science correspondent Andrew Griffin. Sadly, it has been corrected now. But it originally contained these gems:
      “The crater that the mass sits on top of is over-shaped and 2,000 kilometers wide.”
      and:
      “Instead, it was examined by data to sent to researchers by Nasa spacecraft that sent back data on the small changes in gravity around the Moon.”
      You don’t need the tabloids to muck up stories! The Independent made its own meal of that one.
      It’s worth following Andrew Griffin’s articles; he has a unique gift for tortured description. My favourite was the Martian Lander he described as a Rover (but it had no wheels).

  17. Tell me what you think of this. I need some outside perspective.

    caeterarum animarum
    no.2

    After all my years hunting in this neighborhood I have never experienced this, a dog wanting a conversation. I wouldn’t be surprised if he was planning on ambushing me. A dog usually wouldn’t be so cunning but I shouldn’t underestimate Tiberius. I can always use my wings to get away from him, a big dog like that can’t sneak up on anything.
    One of his messengers said to be at this spot by noon but he is late. I am his rival and sworn enemy, at least that is how it has been but why would he want to seek an audience with me now? What exactly is he after and does he think he can get it from me? Is he mocking me? If he is I can make him pay.
    In the distance I can see two small dogs heading in my direction. This must be the help. I must give Tiberius credit, the way the dogs here are disciplined is admirable “Please follow us sir.” One of them says as they bow to me.”This way.”
    It is amazing how stoic and respectful they are, I have only seen Tiberius’s corpses, the way he treats his victims is horrible, slowly killing them over a period of hours instead of a quick death. His bodies show a savage, cruel beast but his men show discipline, respect and intelligence. I am curious about this monster. What is he truly like? What is his goal in talking with me?
    They are beginning to lead me out of this neighborhood and into a wooded area. The more I look at these dogs the more I get worried. These dogs aren’t pets, they are stray dogs and are not even from this area yet they are firmly under Tiberius’s authority. I thought that he only controlled a pack in this area but it would seem his reach is more expansive then I had thought.
    The trees are not conducive for hiding anything but I still feel as if at any moment a dog is going to burst out and attack me. I would not put it below him a cruel beast like him would never shy from using dirty moves like those. Most of the animals here despise me, the hawk, but they have not been in that beast’s teeth. They should feel thankful that I give them a merciful death.
    The tall trees are giving way to an open field and even at this distance I can see his shadow. Even while sitting he is almost as large as a human. I have no idea what type of dog he is but it wasn’t natural. He is sitting in the field with his back facing the forest unfazed by my arrival. I can smell something dead in that area as well. It seems that he has something for me.
    As soon as I enter the field the two dogs bow their heads as I pass ahead of them. “Leave us.” Tiberius says.
    They walk away and disappear into the forest. In front of him he has a body of a recently killed rabbit that has been killed quickly. I face him, his expression is that of a negotiator not a beast. “So why have you requested my presence? I don’t have anything you need and have done you no wrong.”
    “I am interested in seeing the infamous hawk among almost everything fears here.” He says with a calm, almost stately tone.
    “Is this why you set this up? To measure us?” I scowl slightly.
    “No. I have come wanting to discuss business. Please help yourself to the animal, I killed personally and groomed to your tastes.”
    What kind of dog is this?! This tone, his demeanor, his actions are not like that of dogs! “What kind of business?” I have to cut straight to what he wants.
    “Your presence in my neighborhood is detrimental to my goals as such I would like you to leave.”
    “What in the hell do you mean? Do you intend to force me out of this area? That would prove painful for your smaller soldiers.”
    “Give me some credit, if I had wanted to force you out this would not be the way I would go about doing it. I respect you as a fellow predator and would like to avoid a bloody confrontation. Please enjoy the rabbit.
    I must admit it does looks very appealing, there is no point in resisting. “How else I am supposed to take that? You are telling me to leave my territory at your wishes. That would be disrespectful. I am not a member of your pack so don’t think you can order me.”
    He chuckled to himself. “You misunderstand, it is not an order but a recommendation for my sake and yours.”
    “What do you mean? Are you threatening me?”
    “No. You see this area has plenty of animals to hunt. I killed this here and there are scores of rabbits surely this a better place for your type. Here you would be free from the interfering hands of the humans. Here you would not have to worry about competition from me and my group.”
    “Sounds too good to be true.”
    “It is not surprising that you would not trust me so feel free to survey this area for yourself after our talk.”
    “Why would you do all this? What do you want?”
    “I want the neighborhood, I want every cat, rat, and dog to fear my name. that is hard with your distinguished reputation. I would like for them to fear me and me alone.”
    This dog is insane yet there is a charm to his demeanor but where it comes from I can’t figure. “Whatever the case. I would like to thank for providing me with a meal. Most predators would’ve preferred to fight me directly so what stirred you away from fighting me?”
    “I don’t need to. What would fighting you gain me? Respect? I already have that and more. A mutually beneficial resolution to our issues is more accessible then a fight.”
    “You are one of the strangest dogs I have talked with. Not a lot of your kind talk with such charisma or intelligence.”
    “That is just the truth of my species most of us are either too weak or too eager for conflict and we are but at least we are not as bad as cats.”
    I could not help but chuckle at his remark. “A cat could never do what you are doing now.”
    “Do you enjoy meat?” He asks.
    “Very much. I love the texture and the taste.”
    “I don’t care much for all of that fur but I do like the taste. The hunt is what really matters to me.” A devilish smile emerges from his calm expression. “Oh excuse me. Got a little bit excited there.” He quickly regained his composure.
    “I get peckish when I talk about my favorite prey as well. I suppose that is how it is supposed to be. I will take a look around this area before dark and give you me response.”
    “And I will be waiting right here.”
    As I fly away I can still see him just sit there like a statue. I am probably going to say yes, an offer this good can’t be wasted. I would like some insurance though. I can see all types of rabbits, cats, possums and raccoons . Even after eating that meat, I can still feel the urge grasp at them. I spend 20 more minutes looking for a threat but there is none.
    Tiberius is still in the same position all my doubts that were somehow still there is gone. He is crazy.
    I can see a big smile on his face. “Do we have a deal?”
    “Yes. Yes we do.”

    • Depends on your target readership. It has the makings of a good story for early teens perhaps? Try a literary agent if you want to find a publisher.

  18. Star Fleet logo found on Mars 🙂

    Dune Footprints in Hellas

    These curious chevron shapes in southeast Hellas Planitia are the result of a complex story of dunes, lava, and wind.

    Long ago, there were large crescent-shaped (barchan) dunes that moved across this area, and at some point, there was an eruption. The lava flowed out over the plain and around the dunes, but not over them. The lava solidified, but these dunes still stuck up like islands. However, they were still just dunes, and the wind continued to blow. Eventually, the sand piles that were the dunes migrated away, leaving these “footprints” in the lava plain. These are also called “dune casts” and record the presence of dunes that were surrounded by lava.

    Enterprising viewers will make the discovery that these features look conspicuously like a famous logo: and you’d be right, but it’s only a coincidence.

  19. Tomorrow there will be an announcement post.
    It will present a solution to the recent (ahem, well long-standing), problems with extensive Hawaiianisms.
    We will also inform about our brand new rule number 4 in that post.
    The new list looks like this.
    1. Be nice
    2. Thou shalt not spam
    3. All comments about moderation shall be made privately and via email
    4. Thou shalt not Waffle (this one will be explained in depth tomorrow).

    That being said. Here is the verdict:
    1. Turtlebirdman is banned for a full week on Rule 4. This is the final warning before a permanent ban and his 3rd time in the Dungeons, the first two times was on Rule 1.
    2. Jesper, Warning on Rule 4.
    3. Dustdevil, Warning on Rule 4.

    I repeat Rule no 3, this will be enforced on this issue.
    No comments allowed on this.

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