New swarm of deep earthquakes in Katla volcano

This morning (20-May-2015) a swarm of deep earthquakes took place in Katla volcano. This earthquake activity was at depth and it means that magma was moving or dyke intrusion taking place at depth.

Earthquake activity in Katla volcano this morning. The earthquake swarm took place close to 1918 eruption site. Copyright of this image belongs to Icelandic Met Office.

Deepest earthquake in this swarm had the depth of 28,9 km. Shallowest depth was 17,3 km. At this depth there is only magma that can create earthquakes, since crust at this depth in Iceland almost never has earthquakes (it might happen, but is rare event) that is not related to magma movements. This activity is something that needs to be monitored since it might suggest that conditions inside Katla volcano might be changing. There is no way to confirm at this point that to be the case. At the moment there is nothing to suggest that eruption is imminent in Katla volcano at this point. This deep earthquake activity appears to be over for now.

40 Replies to “New swarm of deep earthquakes in Katla volcano”

  1. Jon there has been speculation that Katla is overdue for a major eruption imminently.
    What is your opinion?

    1. Katla is not overdue for a major eruption. Those intervals are irregular. There is always the small possibility for something bigger (1+km3 ejecta), but the max from Katla (7-10km3) is out of reach atm, because of the phase its plumbing sistem is in atm (as stated in a study).

  2. IMHO for Katla: These are in my opinion the final steps to the onset of the last pre-eruptive cycle, or we are in it already. Deeper quakes were constantly but slowly increasing, but lately, the frequency of these deep magmatic quakes has increased substantially, along with the magnitudes.

    This graph will be interesting to see when it gets updated.

    Also of note is a slow but steady inflation, tho not in the pre-eruptive magnitudes.

    Tho it is slowly waking up, Katla is enough of a beast to give clear signs of an imminent eruption. Katla will give us the “oh shit” moment when it decides her time has come and starts the quake storm, and those will be some interesting times, like every eruption onset phase always is. Not to mention wide scale GPS deformation.

    What to expect from Katla? Besides the usual flooding, personally I would expect something on the order of 0.8-3 km3 of ejecta and air travel disruption, depending on the wind conditions. So a VEI4.8 to VEI5.3
    I also expect an explosive eruption (obviously), given the volcano is under a glacier, its explosive past and due to high posibility of evolved magma in the chamber(s) (andesite to rhyolite) below the caldera.
    A new caldera forming event is highly unlikely, but with volcanoes you never know, so there is always that small small percent of probability for every volcano to do something out of the ordinary, which in this case would be the new caldera forming event and/or a VEI6 eruption. But very unlikely is not the same as impossible.

    Bottom line, to wake up a volcano like Katla, it takes quite some time and especially energy. Katla is a “fun” volcano to monitor, and when it decides its time, we will have a great chance to learn something new and to repeat the old. 🙂

    But all the doomsday prophecies around Katla are not really legit. She would really have to erupt above 7-10km3 of ejecta to cause something noteworthy weather-wise on a more global or at least hemispheral scale, given its north location.

    We will see. Katla is my favourite volcano, and its really fun to monitor its development. But untill it erupts, we still have the Vatnajokull activity, especially Grimsvotn starting to get a bit restless in its own respect and Oraefajokull getting some deeper quakes lately. And Oraefajokull is another rhyolitic beast by Icelandic scales, which would be another big problem for aviation and Iceland, and possibly N Europe and UK due to ash, should it decide to go off.

    As I have said for Katla, I expect it to erupt 0.8 to 3km3 of tephra ejecta. For comparison, Calbuco in April had 0.21km3, Mt. Saint Helens 1km3, last Grimsvotn had 0.7km3 and Eyjafjallajökull had 0.25km3.
    So bottom line, we are looking at a possible decent eruption whenever it happens, at least on the order of Mt. Saint Helens, but it could also be easily twice or three times the size of it.

  3. Agree with Mr. Bragason! Nature will do its own thing, but this is a good read. Thanks for sharing your opinion!

  4. The eastern and nothern rift zone seems quite active now. The process starting with the activity last year seems to continue and now it is spring time.

  5. @ David – I live nearby too, I was woken, 2.50am the house shook, it only lasted a few seconds. Thankfully no injuries or damage reported.

      1. I guess the answer is: P-waves and S-waves causing different strains on buildings

      2. P-waves contract the ground in horizontal movements, so chimneys will shake from one side to the other and collapse. S-waves lift the whole house up and down like on waves, chimney stays intact, but maybe whole house collapses if intense

    1. You have to love the British sense of humour…

      And I got the Folkestone quake wrong…is was a 4.3 and shallower. With “Stefans” explanation, it makes sense.

  6. A fun fact about Katla repose time (time between two eruptions), since a lot of people like to say that the current near 100 year repose time will make the next eruption bigger. Naturally, that is a logical assumption to be made, tho some people take it too far and expect another Vedde ash event or a Katlatubo eruption. 😀

    Ok, now the facts: In the past 750 years, there were 4 larger eruptions at Katla, all VEI5. There was also a bunch of 4s and 3s in between of course, but lets look at the big ones in this period.

    In 1262 the VEI5 had a repose time of only 17 years, following a VEI4 that had 35 years of repose time.

    In 1625, there was a VEI5 with a repose time of only 13 years, following a VEI4 with repose time of 32 years.

    Next two are more fun.
    In 1721, the VEI5 had a more normal repose time of 61 years, following a VEI4 with the repose time of 36 years.
    Now the next eruption was in 1756, just 35 years later, and it was another VEI5.
    So Katla had two VEI5 eruptions just 35 years apart.

    But there were also quite smaller eruptions at Katla with longer repose times. So in the correlation sense of “repose time vs eruption strength” Katla is quite a random volcano. The 4 phreatic or subglacial eruptions (55,99,2011,2014?,) since the last explosive euption at Katla (VEI4,1918), probably also had an effect in delaying the inevitable. Katla does have a general period of repose time, ranging from 10 to 100 years simplified, so you could say that Katla is still in its normal repose time and not overdue.

    Volcanoes can sometimes change their patterns (eruptive or repose) on a irregular basis, due to many factors, either geological (tectonic settings, different size/strength of dike intrusions, etc…), “mechanical”(changes in the plumbing system, etc…), etc…
    So personally I dont see a problem or a big surprise that Katla is “relatively dormant” for this long period of time. Its different repose times also tend to approve the fact that Katla is a multi magma chamber volcano, in a sense perhaps like Askja with its pockets of rhyolite with a bad attitude.
    Tho the studies of seismic tomography have shown a fairly unified shallow magma chamber under the whole caldera. I also tend to go with the theory of another deeper magma chamber. But thats for another time.

    Bottom line, the current repose time of Katla is nearing 100 years, but that IMHO isnt something to really worry about, since it is still within the normal operating parameters of the volcano. But it is tho interesting and I am also curious what will come out of it, since there is always a small small chance or percentage for almost every volcano, that it does something uncommon, rare or out of the ordinary for its norm. Perhaps you could put the last Bardarbunga events in this category.

    1. Great comments DW. I wonder how well documented are the factors that affect the actual repose or eruptions are. One such factor was Eyjafjallajökull eruptions being associated historically with Katla eruptions and whether they share plumbing systems and whether these associations are statistically significant.

  7. I know what katla is capable of, but my money is on Hekla for the next eruption. On the subject of climate effect, I do believe holuhrauns emissions are affecting northern hemisphere’s weathers, not just the el nino element, the combination of the two phenomena could give us an extraordinary winter this year.

    1. I do not believe that Holuhraun has any effect on the weather, because the eruption was juat too small (just 1km3) and over too big time span (~6 months), and the sulfur never reached any real height.
      Would it be opposite, 6km3 over 1 month, than you would at least have something better to talk about.

      As far as the winter goes, I also believe it will be colder/snowier in Europe and USA, but not because of the eruption, but as you have said, the El Nino, which has the tendency to make the Greenland blocking in winter, and because of the disruption and breaking of the stratospheric polar vortex.

      1. I have been observing the jetstream data alongside with much other environmental data, the theory that the total holuhraun gas emissions would have had to have been ejected to high altitude is, I feel, trying to write off the massive volume of CO2 and SO2 (the main two of the six gases) that has been expelled.

        An official study was launched in January since the volume was greater than kilauea or Etna. No such study has been done in the northern hemisphere before. There have been many estimates around 35,000 tons per day being one, 60,000 another, I think an average of 20,000/ day over the eruption period more likely. Regardless of the accuracy of these estimates the quantity IS affected by weather conditions and hot and cold air interactions will elevate the gases in the same way as mankind’s pollution. This is more than Europe’s entire emissions by some margin.

        I maintain this will affect the weather and as with all the professional experts, opinions on this are just that.

        For the first time earths atmosphere recorded over 400ppm co2, that was not all ejected it simply found its way via weather systems. Remember NASAs earth observatory forecast it to reach 800ppm by 2100.

        There is an effort being made into ways anthropogenic gases can be removed from the upper atmosphere, I think this was started by all gore if I recall correctly.

      2. Weather is my main hobby for 9 years now (I write as Recretos on the Netweather forum if you know it), and I was paying attention to possible weather effects. But as I said, the output was not high enough. It might sound high, but given the time span and the weather it was in, the dispersion factor was too great to allow this to be of any weather signifigance.

        The tropical configuration and the ENSO transition to more +AAM/GWO state of the atmosphere, doesnt allow for this eruption to have much if any effect.

      3. I think we’ll need to agree to disagree on this one du. It is precisely the longevity of the discharge that has my interest. As you know these gases are miscible, at any cloud ceiling. What are the electrolytic influences of these unstable gaseous compounds on sirus?
        Remember ozone is heavier than air, yet it is earths defence system, there are a great many influences and I am loathe to discounts these holuhraun emissions just because some scientists don’t think it was ejected at sufficient altitude, when the evidence is there that heavy gaseous elements are elevated by weather systems.
        USGS has stated 200m tons of co2 annually is discharged from volcanoes, but as you know that is not at the latitude we are concerned with.
        Net weather is one of the sites I use, I don’t partake in the forums though. We both have a long standing interest, mine stems from my reliance on sea conditions and predictions.

    2. Well, we all have our own views and that is totally fine. 🙂
      But I will not accept the idea that Holuhraun eruption had/has an effect on global or hemisphere weather, let alone the winter patterns. The other drivers simply cancel out its minute effect. Katla with its VEI5s ejected 2-3 times the magma and sulfur in 1/6 of Holuhrauns time and had no known or measurable effect on the global patterns/tenperatures. The scales are just too small. And 1km3 of basalt magma over 6 months is just too small for anything of significance. The next Katla eruption will be the test case. 😀

      For fissure eruptions with actual weather effects, check out Laki with 14km3 ejecta and Eldgja with 19km3 and 450Mt of aerosol H2SO4.
      Laki erupted 122Mt of SO2, while Holuhraun erupted around 3Mt with lower rates and faster dispersion due to much lower concentrations and heights than Laki. It only reaches just over 2% of the Laki eruption and 1.5% of Eldgja.
      And Eldgja erupted 220Mt of SO2.
      Just for the idea of scales. 😀

      Comparing Holuhraun to the actual climate affecting fissure eruptions, is like comparing the global effects of Mt Saint Helens eruption with the Tambora VEI7 eruption. 😉

      Studies will probably be made on this subject, and I look forward to it. 🙂

    3. The weather in North America has been more extreme in recent years. Colder, snowier in the winter, hotter with more tornadoes in the summer. El nino is always a factor from year to year, but what matters statistically is the history of these el nino episodes over decades.

      Long term trends can only be assessed by watching long term events. That’s the shrinkage Arctic ice and the Northern hemisphere glaciers in the summer, the extent of seasonal winter Arctic snow cap, the sea level, the historical northward or southward shift of the jet streams, the extent and thickness of the Antarctic ice, Antarctic seasons and seasonal temperatures, and the growth of Antarctic glaciers. Other things to watch are oceanic and atmospheric changes in chemical and biologic composition and 3D circulation.

  8. Speaking of lethal gas emissions, when will we know how much was retained in the melting snow in the grazing areas. Ergo when is spring

  9. In our area of the upper Midwest we appear to be particularly weather sensitive to Icelands eruptions with both significant rain following the mostly spring events followed by brutal cold weather the last two years followingeyjafjallajokull and GrmsVotn 2011 90 day average mean temp of -20 and spring melt not till may. Not unlike 1948 to 50 following Heckla and 1824 25 and 26 following…. And 1850 and 1861 but the worst was following 1875 for the next 20 years . Of course there was help from Krakatoa and others .
    This years rebound of pleasant above average winter temps and low snow amounts is now reminiscent of the first weeks following eyjafjnallajokull Immense rains in May 2010 and a hot summer . It will be interesting to see if the pattern continues this summer fall and winter .

    1. With all due respect my friends, but you people need to get some sense of scale of these things. Both the scale of weather dynamics and processes and complexity and the scale of eruptions. Both Holuhraun and Eya were just too small to have a noteworthy effect on weather, if any at all. Especially at 60N latitude. If these two would have any notable effect on weather, than pretty much every other volcano eruption in the world, especially in the tropics, would have an effect, and the volcanoes would be driving our weather. In reality, weather is complex and powerful enough with its own oceanic and atmospheric drivers, to easily cancel out potential effects of such small eruptions.
      If Eya in 2010 with its very small 0.25km3 ejecta in 2 months would actually change patterns downstream in USA and around the hemisphere, than the Mt Saint Helens eruption would drop the global temperature and Pinatubo would make a mini Ice age, and Toba 75.000 years ago would trigger an ice age that we would still be in now. But none of that obviously happened with those volcanoes.
      The rainy spring in USA both in 2010 and this year was not caused by Icelandic volcanoes, but by forces much greater and on a much bigger scale. It was configured and determined before the actual eruptions.
      The same goes for other dates, with linkage to ENSO/PDO/AMO cycles. Exceptions are bigger eruptions like Krakartoa or Tambora.
      Interestingly, Novarupta/Katmai VEI6 which was bigger than Pinatubo, had no effect on global temperature and the effects of the VEI7 Baekdu eruption, 10x the size of Pinatubo were very limited.
      When it comes to weather and volcanoes, size does matter. 😉 (And also location and magma conposition)

      1. Pinatubo 17 million tons SO2

        Holuhraun 11 million tons SO2

        So Holuhraun did release a fairly substantial amount of SO2 into the atmosphere.

        One would also do well to remember that the base of the Stratosphere in the arctic during the summer is significantly lower then that of the tropics, and that base drops to even lower heights during the arctic winter.

        Thermal updrafts from the lava field, weather systems, and even the altitude of the eruption site, would have all helped aid the SO2 in the stratosphere…

        Satellite information at the time certainly confirmed the presence of high levels of SO2 in the northern hemisphere strat.

      2. The SO2 delivered by Grisvotn 2011 travelled in the opposite direction to the ash and didn’t return to Europe for a week . In fact it travelled over Greenland and the Canadian Artic Then South West of Hudsons Bay Over western Manitba before turning back east again at approximately 52° North and 100° west. A couple of hundred miles north of Minneapolis. see

      3. Again, scales are being ignored.

        Pinatubo ejected that directly into the tropical stratosphere, which is much more important for affecting global weather than the Arctic strat. And it infused that amount in just 2-4 days directly into the strat, which is the key, creating very fast very high concentrations of H2SO4 in the tropical strat, affecting the energy budget directly.

        Holuhraun ejected quite less sulfur over the period of 6 months, 180 days, with not even half ever reaching a noteworthy height and at a high latitude.

        And with the ElNino onsetting, just accept the fact that Holuhraun is not a weather changing eruption an move on. 😉
        I am not sure why it is so important for some here, to try and prove something that just isnt there.

  10. just a not so frequent location… Wednesday
    27.05.2015 15:36:43 64.008 -18.544 2.4 km 0.8 99.0 16.6 km WSW of Laki

  11. On a global or hemispheric scale I agree with you . I was referring to an area in the upper midwest and Canadian prairies that in this millenia is affected far more by the AO, NAO and Artic sea Ice levels than any but the most extreme NINO conditions . Warm Artic Cold mid Continent textbook case. See Jennifer Francis or Artic Dipole effect or Jeff Masters summares. Those Enlarged Jetstream Loops. Blocking Ridges . Etc. Anything that happens in Iceland has a distinct effect on the AO.and NAO

Comments are closed.