Askja for Beginners

The two lakes of Askja. Víti in the forefront and Öskjuvátn in the background. The mountain ridge in the background is the Caldera wall of Öskjuvatn and not the main caldera wall. Photograph by Boaworm.

I love large caldera volcanoes. The first reason is that they are always very beautiful, especially if they have lakes in them. The second reason is that most of them are of a class of volcanoes that leave their pointier cousins far behind. Size matters after all.

At one end of the beauty spectrum, you have Amatitlán with its lush greenery, flowers, small towns, lake with traditional fisherman, and stratovolcanoes poking out of the morning mist. It is a very human type of beauty but turned to the maximum end of the spectrum.

At the other end of the spectrum, you have Askja, it is stark and otherworldly. The two lakes are different shade of blue, one is a deep blue, and the other is turquoise. It is a landscape of ash and jagged rocks, instead of flowers hiding the raw power, you get the beauty of raw power undiluted.

I do not know if it is my knowledge about volcanoes causing it, or if it is some sort of weird affinity, but at calderas I can always feel the monster deep below murmuring to me when I visit them. Only one other volcano has ever talked to me like that, and that is Hekla. After all it is in the pre-stage of going caldera.

Regardless of type of caldera, or location, they can and often do quite a bit of alterations in the landscape without even erupting. Something that I will discuss more below.


What is a caldera?

Compared to Boaworms more detailed picture we here get the inner and outer caldera walls for scale. Photograph by Wolfgangbeyer.

I will here simplify things a bit, but generally a caldera volcano is a volcano with an underground volcanic system that is too big to be contained by the edifice above it. The feed rate from the depth is to large over time and magma reservoirs build up over time to prodigious sizes.

For a subduction volcano the calderification is often explosive, and for mantleplume volcanoes the calderification is often effusive. Exceptions do obviously exist, some mantleplume volcanoes explode, and some subductions effuse themselves into big holes in the ground.

In Iceland the large calderas are mainly caused by effusive eruptions draining large magma reservoirs, causing the overburden to drop down into them. Either in a blocking calderification where the overburden breaks up into blocks and drop down (Askja for instance), or as a piston (Bárdarbunga), where the magma reservoir is so deep that the entire overburden moves down in one piece (more or less).

Katlas calderification is less well known, but it is presumed to have been mainly effusive in origin. Grimsvötn is the oddball here, it has 3 calderas that formed during the Saksunarvatn tephras, a series of 5 very large explosive eruptions.

Obviously all four volcanoes have dabbled all over the spectrum, but as a general outline this is good enough.


The Icelandic Calderas

Icelandic volcanism fill the entire spectrum. At the lowest end you have tourist eruptions like Fagrafjall (the mountain formerly known as Fagradalsfjall). After that you have central volcanoes like Eyjafjallajökull that can at times be a spot of bother.

Next in order are the bigger central volcanoes, and minor caldera volcanoes. Here we find Hengill, Hekla, Krafla, Öraefajökull, Torfajökull. There are around 10 of these that can cause some serious problems for air traffic and the local population.

And at the far spectrum you have the Big Four. Askja, Bardarbunga, Grimsvötn & Katla, these are the volcanoes that potentially can cause problems on a global scale. All four of them have deep magma reservoirs, upper magma reservoirs, fissure swarms, and in some cases even satellite central volcanoes on their fissure swarms drawing from the same deep magma reservoirs.

As volcanoes go, they are very versatile and can do a wide number of different types of eruptions at different scales of destruction. From minor mild effusive eruptions to big climactic eruptions altering world weather patterns.


Askja Caldera

This might end up an article one day. The two types of eruptions out of the Big Four. A is Dyke Propagation eruptions, Holuhraun is a splendid example of this. Type B is a Lakí example.
I have often talked about the elongated deep magma reservoirs under Grimsvötn and other volcanoes, here is finally a good picture of it. And yes, all of the Big Four have those deep reservoirs, but can erupt either as A or B depending on the location on their respective fissure swarms.
Image from Hartley & Thordarson 2013; “The 1874–1876 volcano-tectonic episode at Askja, North Iceland: Lateral flow revisited”.

Askja is an old volcano, it is at least 200 000 years old, so it has had ample time to evolve into the volcano that we see today with all its sub-features. It is a nested caldera, and the original caldera event is unknown. One guess is that it occurred during the last ice age, we do though know that it did not happen post-glacially.

The outer caldera has been infilling with fresh effusive lava, as well as deepening at least once post-glacially during the 10 000-year-old large explosive eruption. This eruption was either a very large VEI-5, or a VEI-6 eruption.

It is also possible that a couple of large (5 cubic kilometre sized) effusive eruptions increased further the depth of the caldera.

The inner caldera we can though date with a fair bit of accuracy. It happened during the 1874-1876 volcano-tectonic event (it was so complex that the word eruption is not sufficient, hence the event moniker).

It all started in 1873 with the unrelated eruption of near Holuhraun I. Up until a decade ago it was believed to be an eruption in the same sequence as Askja, but we now know that the lava came out of Bardarbunga due petrochemical testing as well as having experienced Holuhraun II.

I am here leaving out that Holuhraun I (1797), would imply that the 1873 eruption would be Holuhraun II and the 2014 event would be Holuhraun III (aka, Nornahraun which is the official, but never used name for what should be Holuhraun III but is known as Holuhraun II). It is Iceland, it is confusing, and the recently erupting mountain should be renamed into Fagrafjall since it is a pretty mountain. I digress as per usual.

The only reason that I mention this eruption is that there might be a regional eruptive circle going on here. If so, the Holuhraun II eruption in 2014 might be related to an upcoming eruptive cycle at Askja. But many might bees, ifs, and buts… So, please take it with a huge pinch of salt.

Prior to 1874 Askja was relatively unknown, just one minor volcano causing minor mischief in the hinterlands of Iceland. With Katla, Öraefajökull, Hekla and Grimsvötn doing their best to kill people in Iceland nobody noticed it to any degree.

In 1874 a rifting fissure eruption started 45 kilometres north of Askja along the Sveinagja Graben, with epicenters slowly opening up closer and closer to the volcano, with the last one only 25 kilometres north of the volcano. A couple of hardy Icelander’s hiked up there and noted that it was impressive, but nothing like their grandfathers had seen during the Skaftár Fires (Lakí) 101 years prior.

An impressive rift eruption in the hinterlands was though not much to write home about in Iceland.

Map of Askja with GPS-stations marked out.
Image by Icelandic Met Office.

Inside the caldera all was calm on the surface, well probably since nobody bothered with checking. With modern equipment the picture would probably have been different. What we now know is that hot fresh material was coming up from the deep reservoir, and it went into an old stale disconnected magma reservoir. That magma reservoir was filled with evolved magmas, and it was rapidly heated by the fresh intruding material.

On the 28th of March 1875 a sub-plinian eruption started from that old magma reservoir, it rapidly grew in strength and on the 29th of March it turned into a climactic phreatoplinian eruption. This part of the eruption was a VEI-5 event causing so much distress in Iceland, due to killed livestock and poisoned water wells, that many had to leave the island permanently.

The ash travelled over to Scandinavia where ash was found all over the place, quite to the initial surprise of everyone there. This part of the eruption left a crater behind that later on filled with turquoise water, today it is known as Víti.

The eruption continued until 17th of October 1875 in abated form. At this point the calderification began as the magma reservoir near Víti started to block up and drop down. After more than a year of blocking a caldera had formed that was more than 12 square kilometres in size.

It started to rapidly fill with water, and it is today known as Lake Öskjuvatn, it is 220 metres deep, and from time to time suffers from caldera wall collapses. At the beginning it was quite warm, but nowadays it freezes over during the winter.

After this climactic eruption came a series of seven eruptions between 1919 and 1938 where dregs from the large intrusions was pushed out. And in 1861 there was a small rift eruption at Vikraborgir that came from the deep reservoir, but that seems to have been unrelated to the Askja Caldera.


Caldera Landscaping

The intrusion, slowly abating. Image from the Icelandic Met Office.

The problem with Iceland is that Askja’s 3 siblings are all iced over. This means that we do not have any good data from inside the calderas of Bardarbunga, Grimsvötn and Askja. We can only infer from distal data what might be going on, but we do not see what the caldera floors are up to at any given point in time.

Instead, we will have to look at historical data from other large calderas around the world that are active. What we find there is that they can perform some serious landscaping without even being close to erupting.

Even the comatose Yellowstone can cause quite a bit of uplift, earthquake swarms, and new geothermal features and geothermal blowouts, without it being a sign of an upcoming eruption.

The King of Landscaping is obviously Campi Flegrei that can do several metres of uplift without erupting. And let us not forget Amatitlán that is slowly tilting to its side, drowning entire towns on one side, and uplifting other towns on the other side. One entire Mayan city is now under 30 meters of water.

There is something to learn here. Big calderas equal big landscaping. And even big landscaping does not equate an eruption. At Campi Flegrei and Amatitlán we have very long historical records, but at Askja we do not.

For Askja we have data from 1961 and onwards, from the beginning the data was simple tiltmeters, and today we have a good GPS-network combined with all sorts of other equipment. During these 61 years we have seen several minor deflation and inflation events, but nothing major.


Askja Today

Same station, more years.
Up-Down, Up-Down, Up… Spot the actual intrusion game.
Image by the Icelandic Met Office.

Let us begin with what we see at Askja, what the data gives at hand. We see a well-defined area of inflation inside the caldera that is nearing 40 cm in upwards motion. We know that the area affected is small for being inside a large caldera and situated NW of Lake Öskjuvátn.

The distal impact of the inflation is very limited outside of the caldera, in fact it is less than the inflation rate post the 1961 eruption judging from the limited data available back then. We also know that the intrusion is shallow in origin at between 2 and 3km depth.

We also know that the intruding volume is small, between 0.001 and 0.003 cubic kilometres, and we all know that this is not something to write home about in Iceland. If this would erupt it would be an Icelandic equivalent of a shart.

What is not being seen at Askja is probably more interesting. And there is a lot of nothing to be had. Let us start with what the intrusion is not.

We are not seeing any evidence of an increased rate of magmatic inflow from depth, nor are we seeing a deep intrusion taking place, this explains in turn the minute volume of intruding volcanic fluids. This is not good news if you want a big boom at Askja.

We also see background levels of seismic activity. Prior to an eruption being close we would see quite a bit of activity on this front. It is even probable that we would see several large earthquake swarms spanning years prior to the start of an intra-caldera eruption.

We are also seeing no increase in volcanic gases, nor do we see an increase in geothermal heat output in Lake Öskjuvátn, except for a minor heating event a few years ago heating parts of the lake a bit early in the spring.

So, if it is not Hellmageddon 3000 that we are seeing, what then is it? Let me speculate here a bit, but it is speculation based on fact and data from other similar volcanoes, so I do not expect to be far off the mark.

What we are seeing is accumulation of volcanic fluid in a limited reservoir. I do not think these fluids are magma, instead I think it is water moving into hot ambient rock, causing the water to expand further as it heats up. Basically, we are seeing a deep geothermal field being born.

As the size increases of the field there is a minor risk that this will cause a phreatic upwelling and a Maar will be born. It is not as of now a sign of an upcoming major eruption.

This being said, sooner or later Askja will erupt again, after all it is what large volcanoes do on a regular basis. Prior to that we will see a lot more activity. For now, sorry to be the party-pooper.

Carl Rehnberg

83 thoughts on “Askja for Beginners

  1. If I find more than one comment-thread about Ionization of Io I will get mighty miffed.

    One thread to rule them all, etcetera.
    Otherwise I will start chucking comments into Orodrúin. 🙂

    And yes Jesper, that means that you do not get to do ionoclasting in more than one thread.

    • Well I moved them To the VC Bar
      But seriously Ionian Volcanoes Maybe the most intresting of all volcanoes

      Anyway will Askja erupt now then ?
      With luck Maybe Askja will be very active like it was in 1920 s ? Hopes to visit Askja when I moves To Iceland in the future

      • I think I just wrote an entire article answering your question 🙂

    • Most Impressive thing with Askja is How long it can intrude magma .. was one of the 1800 s intrusions kind of 100 km long ?

      • 45km long to be exact.
        But, there are a couple of older ones that went 100km if I remember correctly.

        • Measured on google earth it is about 65-70 km from the north edge of Askja caldera to the northernmost fissure of 1875. The fissure line is 24 km long, but most of the eruption seems to have been near the north end, the southern fissures are barely more than spatter cones. I also read somewhere there were many separate eruptions over most of the year, it was not a single event like Holuhraun.

          It is quite clear to see the path of the dike in the landscape. There are lots of large faults in the ground, mostly near the fissures but even as far as the base of Askja itself. The faults are widely separated in the south and narrow as you go north, showing the dike getting shallower.

    • Yessss wants to move to Iceland
      These High Fantasy Dark moody volcano – glacial landscapes is like a dream .. specialy the Laki fields or Katlas Coast .. scenic as Hell really its like a dream really

      Its now Impossible for me to not think of Iceland every minute.. I haves to move there ! looking for ways

      Indeed Iceland is tastey as hell 🙂
      And really unique

      Big Island does not have unique these landscapes .. its just an extra overgrown tropical deep ocean Island

      PS Askja also haves its own Geothermal pool an extra bonus

    • Excellent Article anyway .. guess I haves to visit Askja Lakes one day

    • Very nice piece, Carl. I am a bit absent here because of a knee problem that affords some lying down and all other work done at a slower pace. Happened while gardening, most dangers are hidden in House and garden, ladders and spades. It happened while digging a whole with a spade, very simple. You survive though, at least if no ladder is involved. I hate it.

      Amatitlán and Campi Flegrei are fascinating because they are inhabited. Therefore there are more historical data, of course. Askja is beautiful and not that dangerous because of a lack of population.

      My favorite caldera is a caldera in a caldera in another caldera with a volcano on top, no lake. This is, of course Las Canadas IV aka El Teide.

  2. Thanks Carl! Another hoped-for eruption to cross off my bucket list… Viti’s colour always fascinates!

      • Is that also the reason for the turquoise colored rivers I saw coming out from the glaciers on the Bergen – Oslo railway?

        • Not a clue, but it is possible. It is definitely some sort of suspended matter.

          • Yes, this deposition of silica puzzled me for quite a while.
            One plausible mechanism is that soluble silicates (Na, K etc) on meeting air would react with CO2 to form carbonates and silica. Silica being VERY insoluble it would precipitate out even if silicic acid were more acidic than carbonic.
            This will only work if the water is rather alkaline so alkali metal silicates can form.
            K2SiO3 +CO2 -> SiO2 + KCO3 (via carbonic acid).

            Alternatively (and perhaps more likely) hot water dissolves minutely more silica than cold, and it just precipitates out when the saturated water cools. Given the very low concentrations even in hot water, the precipitate would be very small crystals indeed.

            Wiki”Water solubility

            The solubility of silicon dioxide in water strongly depends on its crystalline form and is three-four times higher for silica[clarification needed] than quartz; as a function of temperature, it peaks around 340 °C.[51] This property is used to grow single crystals of quartz in a hydrothermal process where natural quartz is dissolved in superheated water in a pressure vessel that is cooler at the top. Crystals of 0.5–1 kg can be grown for 1–2 months.[8] These crystals are a source of very pure quartz for use in electronic applications.[11] “

          • And here it is good to remember that Blue Lagoon is geothermal wastewater stored in that hot pool cooling off before getting pumped down again.
            Víti is also geothermal water squishing up naturally, so it is easier for suspension to form.
            And yes, this is the beginning of a nice little mineral deposite.

        • That is a gorgeous journey! Did it in 1977. I remember those waters well.

        • Very similar – those would be rivers running out from the snouts of glaciers carrying very finely milled ‘rock flour’ that has been crushed by the movement of the ice. The Hvíta (white) river in Southern Iceland is similarly milky from all the debris being carried down from the Langjökull glacier.

  3. Recently, the urls for the FAF drumplot and tremor have stopped working for me. What gives?

    • Icelandic weather happened.
      Most likely the seismometer will be moved to a more interesting volcano, it was one of the Icelandic movable stations.

      • It’s not just the graphs being noisy, not updating, or having gaps. I now get “404” errors for both, as if they never even existed. It’s quite bizarre.

  4. If this was the beginner level article about Askja, then I can’t wait for the intermediate level version. All the details it would include…

    For the advanced level article I would then expect it to be written in Islandic, just to increase the level of difficulty for most of us.

    • Excellent idea, I will get right on it 🙂

      In reality this was one of those articles where I intended to keep it short and simple, and failed miserably and it turned into a 4 page article.
      Askja = No, kind of needed an explanation. 🙂

      • Don’t worry, the exam is not until next week. Plenty of time for revision. Perhaps it will only have one question ‘which Icelandic volcano exploded in 2010’ with all marks given for spelling.

        • Eyjafjallajokull, spelled off memory 🙂

          Or as it sounds to those not well versed in Icelandic, Ayafyaltlayokutl 🙂

          • Impressive. But can you do it at the exam and using the Icelandic alphabet? (Which admittedly only differs in one letter from yours.)

        • No, it will be a two parter.

          1. Which two East and West volcanoes erupted last in 1783? Write an essay on how you translated their name in your reporting for Al-Jazeera.

          2. Which volcano caused a commotion in 2007 with a large deep intrusion? Write an essay on how you translated it for Fox News.

          • Is that the actual serious real name of the mountain, not just a random name given to a formerly unnamed mountain?

          • No, that is a very serious set of names.
            Nordic language humour is an acquired taste. 🙂

            In Sweden we have both ‘Menstruation Swamp’ and ‘Bovine Vomit Regret Snot’ as names for places.
            And let us not forget that prominent parts of Stockholm are named Moist Vagina, Yankballs and Balls Torture.

          • I do know of a volcano in the San Francisco volcanic field that had somewhat of a “cursed” name. SP Crater was named by some rancher in the 1880’s by the name of C.J. Babbit. Initially, he thought it looked like a chamber pit (i.e. basically a toilet), so he called it Shit Pot Crater and, later on, people called the particular cinder cone by that name.

            The map makers, however, did not want to spell out the whole thing, so it eventually became SP Crater. To this day, the cinder cone is a little controversial, not by its name, but ratherly its age and the way it is formed (the question of either the lava flow came first or the cinder cone came first). Just a odd fact to give out, since I knew about from Wikipedia.

  5. Askja is a very Intresting volcano because its a volcano that can do almost anything.Depending on the magma composition ( which chamber ) and the gas content and many other variations.

    It ranges from decades decades long lava shields and decade long pahoehoe plains emplacement.. to near Laki scale fast Fissure eruptions, to smaller Galapagos and Piton De La Fournasie like Fissure events. And it can do sillic plinians and pyroclastic events and even lava domes If it erupts from shallow stale chambers. Bimodial Caldera .. but Askja is mostly basaltic in composition ..

    The staler the supply the more sillecous in composition Icelandic Central Volcanoes get in their upper chambers .. haves a felsic body inside them, Askja blew out most of its sillicous magma in 1870 s event

    Grimsvötn and Bardarbunga haves high enough supply to be almost purely Basaltic

  6. A couple more Icelandic calderas:

    There’s been a suggestion that Krýsuvík has a caldera, albeit buried.

    Torfajökull has a caldera and has produced both basaltic and rhyolitic lavas. A silicic eruption from here may be interesting.

  7. Recently I wrote a new Geology section in the article for Viðey just off the coast of Reykjavík, discussing its Pleistocene caldera geology.

    I did what I could to supply it with references. One of the references is a link to a specific section of a detailed (but mostly unlabeled) geology map of Iceland, and it indicated there are other similarly old calderas underlying the Reykjavík metropolitan area.

    But they’re harder to google information about. It’s complicated by the fact that when you google anything that involves Reykjavík, it will either refer to all of Iceland, or mention a feature’s geographical distance from Reykjavík, but it hasn’t been easy to find detailed in-depth textually-described geological information on the Reykjavík area itself.

    It would be interesting to learn a lot more about Iceland’s less-recently-active calderas, like those that last erupted more than thousands of years ago. The geology map reference teases the locations and shapes of various such older calderas, but does not give them names or other more specific information. I want to find more and read more!

    • There are no large Reykjavik Calderas that recent.
      But, you have the Esjan Volcanic Complex, and that is a big one.
      It is though a lot older, about 1 million years old, and have not erupted during or after the last glacial.
      But, when looking at the deep structures there’s a lot of hot material still there, it is probably the oldest Icelandic volcanic system that is still receiving hot material without erupting.

      • I know there is nothing in Reykjavík that recent. Even the Viðey caldera is about 2 million years old and long extinct. I’m still curious about those extinct calderas though. 🙂 I’ll certainly read more about the Esjan Volcanic Complex.

      • 1 million years ago was still the Pleistocene, just not the late Pleistocene that is what most people think of. That is sort of arbitrarily given as the last 100,000 years up to 13000 years ago I think.

        Its really a bit silly how the Holocene is given its own epoch, when we consider the other ones in the Cenozoic all lasted multiple millions of years and the Cretaceous period on its own was longer than the whole of the Cenozoic… Also that there were many other interglacials exactly like this one. Only real difference is what we have done to the environment and megafauna but then most of that is basically modern history, not 13000 years old.

  8. Looks like Etna has leaked a new fissure within the last hour, at a much lower level. But I’m assuming that as it’s still in the Valle del Bove, it’s not a danger to settlements yet. The following is from the Etnative Facebook page.

    COMUNICATO DI ATTIVITA’ VULCANICA del 2022-06-07 18:41:17(UTC) – ETNA.
    L’Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, comunica che sono state osservate delle nuove fratture alla base della parete settentrionale della Valle del Bove, in zona Serracozzo, dalla parte più a valle di questo sistema di fratture sta avvenendo emissione di lava. Il punto di emissione si trova ad una quota di circa 1800 m. E’ in corso un sopralluogo da parte di personale INGV. Per quanto riguarda l’ampiezza media del tremore vulcanico, dalla tarda serata di ieri, si osserva una fase di graduale decremento che ha portato tale parametro da valori alti a medio-alti. Le sorgenti del tremore sono localizzate nell’area del cratere di SE ad una quota di circa 2900 metri sopra il livello del mare. L’attività infrasonica è bassa, tuttavia il forte vento di stamattina potrebbe aver inficiato il rilevamento degli eventi infrasonici. Da una analisi dei segnali di deformazione del suolo, non si evincono variazioni al di fuori del rumore nelle ultime ore alle stazioni delle reti clinometrica e GNSS.

    • Giggle translat:

      VOLCANIC ACTIVITY RELEASE of 2022-06-07 18:41:17 (UTC) – ETNA.

      The National Institute of Geophysics and Volcanology, Etneo Observatory, reports that new fractures have been observed at the base of the northern wall of the Valle del Bove, in the Serracozzo area, from the most downstream part of this fracture system, lava is being released. The emission point is located at an altitude of about 1800 m. An inspection by INGV personnel is underway. As for the average amplitude of the volcanic tremor, from late yesterday evening, a phase of gradual decrease is observed which has brought this parameter from high to medium-high values. The sources of the tremor are located in the SE crater area at an altitude of about 2900 meters above sea level. Infrasonic activity is low, however the strong wind this morning may have affected the detection of infrasonic events. From an analysis of the ground deformation signals, no variations outside the noise in the last hours at the clinometric and GNSS network stations are deduced.

      • It is in this area.

        Actually, very far down the mountain relatively speaking, the flow is very slow but if it is part of a dike then we might be looking at a more distant flank eruption soon, something like 1929 or 1971 which both also happened in this same area. 1929 was very destructive.

      • Hmm. Since ‘the Sicilian affair’ I have a hard time believing anything from “Sezioni di Catania Osservatorio Etneo Instituto Nazionale Geophisica e Vulcanologia” …

        • They are good sports, according to persistant rumours they are still giggling from The Sicilian Affair.

      • Its inside valle del bove not outside according to INGV Thermal webcams

        • Yes, under the Serracozzo, which is where I marked. Quite surprising, the flow is very slow, the lava erupting higher up is much more fluid and faster, almost pahoehoe, but this new vent is so viscous it almost doesnt look like a liquid. Must have been moving slowly underground for days maybe, and a bit leaked out now.

          • Remember what you saw in Leilani. The vents there initially were very viscous. They pushed out magma that had collected there years before

          • 1978 lava erupted in this same area and flowed at speeds of at least 3 km/hr, reaching near inhabited areas within a few hours. Goes to show sometimes Etna does erupt very fluid lava. My guess is most of the time it is effusive we see the lava that has been cooling in the conduit, if we get some sort of shallow magma chamber forming then eruptions might get larger and with both higher effusion rate and more fluid lava, which could be rather dangerous. Also for the fact such a situation would likely end with a major lava flood down on the lower flanks.

    • Many slow lava flows vent are active in valle del bove now supplying lava channels and Aa flows downslope its been going for weeks soon. I wonder If it will form a lava tube .. in more fluid basaltic flows that woud have already happened .. Althrough the eruption Maybe too fast to form a lava tube

      • The view of the flow heading towards the distant city lights was a bit disconcerting.

  9. Speaking of calderas/possible large eruptions, the other day Tallis Rockwell mentioned the Chiles-Cerro Negro volcano on the border of Ecuador and Columbia.

    There is a new video by Geology Hub referring to this (apologies, not sure how to embed it)…

    • It’s about time someone else mentioned it! This volcano can’t seem to be quiet for very long and stays pretty interesting but Taal is still on the top of my list

    • It is still early days, but it does indeed starting to look a bit like it may have had some effect on the global weather patterns.
      Obviously we will not know until the end of the year if true, but there are a few pictures from ISS that looks very much like it did after Pinatubo.

      • More study needed! It is also a La Nina year and that has a big impact on Australia. The weather has been peculiar for almost a year. But frost in the north is not normally associate with La Nina. The amount f dust was insufficient to affect the climate, and the sulphur content of the eruption was very low so that would not have done it either. But the injection of water into the stratosphere may have had an effect on weather patterns. It caused a sudden stratospheric warming over Antarctica and was perhaps to blame for the Antarctic heat wave. I am wondering whether the southern jet stream was affected.

        • Yes, lot’s of them.
          Here the summer seems to be indefinitely postponed.

          I am the first to say we need more data, preferably a full year at least.

          But, a wild guess is that we have one factor working towards cooling, and that is crashing with the general increase in heat. We have both superheating (India par example), and a large area without summer spanning from Scandinavia down to Rostov-on-Don.
          Also, wars tend to affect climate. People forget that the winters during WWII was arse cold.

      • 20 C in Malmö: not summer? Pretty hot in the sun anyway .. 26 C in shadow is too hot for me

        But I know that Carl wants around +45 / +50 C in shadow to thrive

        But I gets problems at over 20 C

        • It’s 17 degrees Celsius here.
          We’ve had one day with +20, and that day ended in a storm and back to 13-14 degrees.

      • Looks like the eruption had effect.. not superhot yet in Mediterranean .. and been mild in Otherwise hot regions

        And effects of Chicxulub is not to be even thinked off ..

        Tonga Reached almost 60 km up with its eruption plume

        • 44 degrees in spain, they never had these temps so early in the year

      • Carl, would you happen to have a link to the images from the ISS you’re speaking of? When you mentioned them a few days back I was looking but couldn’t really find anything, but I was probably looking in the wrong places.

        If you have some time, no worries!


          • No worries man!

            If you happen upon them again sometime do share with us. That’s very fascinating.

        • And Holuhraun is more like “Whole-you-phrain,” right?

          Wife and I have been trying to learn more Icelandic, we’ve only been there three times now with a forthcoming two week trip this October!

          My favorite place on earth.

          Last time we languished around Snaefellsness for days and meandered all over the peninsula with no particular itinerary. Just gorgeous.

          • I actually dont know any meaningful Icelandic, only names of some places and meanings of those. Probably the same as a large chunk of the internet after this past year.

            Holuhraun sounds like Holohroon where the R is rolled and slightly with an L sound, it sort of Most of this is from watching the Reykjavik Grapevine and listening to Valur’s accent 🙂 Probably to someone with a native language in that family it sounds different, but to me Hraun sounds like it rhymes with Dune.

    • Flank vent is still going, looks a bit less viscous than before too. Still not like the older vents but those were pretty viscous to start with too. Maybe the lower flank vent will get more fluid over the next few weeks, could become a problem if it lasts a while.

  10. Theres been some more quakes at Grindavik and also more generally in that part of Reykjanes. Some are quite shallow too under 3 km depth, so might mean it has only to recieve a slight push to erupt now, one more intrusion might be one too many.

  11. Nope, if you filter for M2+ earthquakes that are fairly reliable in regards of depth, then it is quite obvious that the magma is stuck still at 5km downwards.

    • Note that the advisory stated : STATUS: EXER which presumably stands for Exercise. The volcano is just exercising and VD was a touch jumpy today.

      • Ah I see. It trapped me abroad for an extra week in 2010 (not 2011!).
        Was hoping it would trap me away from work by acid raining down my factory this time round.

    • Nailed the spelling.

      For anyone who’s seen “The Secret Life of Walter Mitty,” it contains my favorite mispronunciation of that volcano “ Ey-ya Flooti Koot.” Lol. Brilliant.

      “Ey-ya Fyat-la Yo-Koolt” is generally how I say it after listening to native speakers. It’s said quickly and with all emphasis on the “Ey-ya,” but that’s a good approximation.

      • Tuppence Middleton plays an Icelander in Sense8 and pronounces it along with a few songs.
        Not sure how correct the pronunciation is.

  12. It looks like the Smithsonian site has ranked the Hunga Tonga-Hunga Ha’apai eruption as a VEI 5 now, but from the evidence I had read it was said to be a VEI 6 slightly larger than Pinatubo.

    • Perhaps they got it from us.. Or they are being cautious as it is now clear it is either high VEI 5 or low VEI 6.

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