Posted on by Jón Frímann

New earthquake swarm in Katla volcano

After few quiet days in Katla volcano. It seems that new earthquake swarm is about to start in it. But this earthquake swarm did start with a ML2.8 earthquake (automatic size) at 10:55 UTC. This earthquake have been followed by smaller earthquakes. So far there have not been many earthquakes in this earthquake swarm. But the largest earthquake took place on what I think is the fissure where the eruption in the year 1918 took place.


The earthquake swarm can be seen here. Copyright of this picture belongs to Iceland Met Office.

The largest earthquake clearly has magma signature in my opinion. As it can be seen on my geophone recording of this earthquake.


The ML2.8 earthquake. This picture is released under Creative Commons Licence. Please see licence web page for more details.


High resolution of the Katla volcano ML2.8 earthquake. The bump later on this earthquake trace is the second earthquake that only had the size ML0.9 according to the automatic size estimate. This picture is released under Creative Commons Licence. Please see licence web page for more details.

There seems to have been some type of tremor event on Goðabunga SIL station just before the earthquake. I am not sure what event this was. But it does not appear on other SIL stations around Katla volcano.


Goðabunga SIL station. Copyright of this picture belongs to Iceland Met Office.

For the moment the only thing that can be done is to wait and see what happens in Katla volcano.

194 Replies to “New earthquake swarm in Katla volcano”

  2. Interesting events, seems there are still some quakes happening..
    Still wondering if there will be bigger swarms happening without an eruption before the actual eruption. Or that there just will be one big swarm with large quakes which starts the eruption and that we continue at this slow pace

    Sander

  3. I’m not sure where the ML2.8 took place, but the majority of the quakes seem to take place under the 1955 eruption site and stretching towards the larger site of the 1755 eruption.

    http://strokkur.raunvis.hi.is/~sigrun/KatlaSigrunEnska4.png

    Austmannsbunga GPS keep hovering between 40 and 60 mm uplift, but I’m not sure how much of that is seasonal variations due to Myrdalsjøkull glacier gaining and loosing weight.

  4. @ the guy who wanted the recepie for Janssons Frestelse. And this is something right up my alley since food and cooking is a great passion of mine. 😉

    (So waaay OT this one.)

    10 potatoes
    2 yellow onions
    200g Anchovies
    3 dl cream (high fat)
    3 tbs finely grated breadcrumbs
    2-4 tbs butter

    Peal the potatoes and cut it in 3-4mm thin slices (like french fries). Rince these in cold water to get rid of some of the starch.
    Peal the onion and cut it fine.
    Butter an oven proof form. Put in potatoes, onions, anchovies in the form. Repeat this until the form is full and end with a layer of potatoes on top.
    Remember to season but not too much since the anchovies are very salty to begin with.
    Pour some of the juice from the anchovies tin over it and pour the cream over it also.
    Cover with the finely grated breadcrumbs.
    Put in the middle of the oven for about one hour at 225 degrees celsius. Try it with a stick and if the potatoes are soft the dish is done.

    1. @ Daniel
      All I need to do now is wait ’til my wife cooks it; we like fish and I grow onions and potatoes! Many thanks.
      A

      2. We cook a similar dish, only with sausage instead of fish and with apples on top. I have cooked it also with fish and used peaches for the fruit, also very good. We use small sausage link like for breakfast but you can use any kind you prefer. Brown the sausage and onion, then potatoes sliced & black pepper, then apples cut in 1/8ths with some cinnamon.

    2. (Still OT) If you prefer fresh fish replace anchovies with 400-500g of fresh salmon slices and add 1-2 teaspoons of salt.

      1. As well I’ve plenty of taters ‘n’ onions; thanks all! I think we’ll try all variants. Yummeee

    1. That seems to be some ground deformation. The one reason I would not think it is equipment error is that both North and East component are showing quite large fluctuations too.

      Just wondering what could cause this.

      2. Pieter, it is the same GPS-station.
        It is just that her plot is not run up to date since the data-off point due to maintenance.
        I would be a bit carefull about any sudden changes in altidude right now, some of the stations seems to have been moved slightly (millimetres) when they did the maintenance.

  9. “And ye shall hear of wars and rumours of wars: see that ye be not troubled: for all these things must come to pass, but the end is not yet.”
    Matthew 24:6

    1. Oh yeah who walk in the shadow of the valley of Gargleblaster…

      Henrik, how are you today? Are you going religious on us? Take 14 beers and call the doctor in the morning 🙂

      1. Translation:
        And you shall hear of tremors and rumours of coming eruptions: do not overly excite yourself: all these things will come to pass, but not yet!

      2. well that’s better, maybe now you can share some of the 14 cans you have with the rest of us. 😀

        As long as you’re not in front of the webcam naked, when Katla finally goes, quoting bible talk, swinging a stick, you will be ok in my book.

      3. Rick:
        You know about my bet about Katla?
        If Katla blows before Hekla I would be bbq:ing my hat naked and dancing infront of the Dalek on Hekla cam.
        But I promise that there will be no bible-quoting.

      4. Didn’t we tell you? Carl is to eat his hat while dancing nekkid whilst I quote scripture.

        Seriously, that quote proves we haven’t changed one bit in 2,000 years as every little burp, hiccup or wiggle in the tremor plots is seen as a surefire sign of an imminent VEI 6 or worse.

      6. : ) HIGH five there Henrik!! ……. *but not yet!* indeed!
        (I just had to pop up from lurking mode to raise my five in agreement, okay back it is I go now : ) Oh and just a moment please with an OT, Jon and all you who post here thank-you so very much for this fantastic learning forum. I just love it!! Not only are you serving up information of the sweet and delicious kind, but you serve up lots of meat and potatoes kind of info too that I especially enjoy reading, and digesting some odd bits from. Thank-you Thank-you Thank-you. Now back into lurking mode with some neat new recipies too to try out. Big Smile from Toronto!

    1. I saw, thanks for that. Does the email you provide go only to you or is seen by more people?

      Sorry for the OT as well. Back on topic after this!

  13. Oh Good grief! I go off to spend a happy morning on my new allotment, digging over and removing garbage that the previous owner stupidly buried. I come home and what do I find? Ms Katla has gone all active as soon as my back is turned!
    @ Daniel. Mmmmm! Could you come over and drop some of that off for my evening meal tonight please? I shall try that .
    It looks like tonight I shall be here for company and watching . It will be interesting to see if my presence has any influence on magmatic activity. I f Katla goes quiet again I shall start getting paranoid!

      1. That’s because I am Home for the night. If she starts bubbling again after 10.am today when I am out I shall start a Lurking type plot to verify the association!

  16. I had a spout of paranoid conspirational theory regarding Hekla and Katla after being influenced by Diana.
    I got it into my head that they could co-erupt, or more to the point that an eruption of Katla could make Hekla go if it was filled with magma.
    After some digging (I threw in Eyjafjallajökull, Torfajökull and Vestmannaeyjar for good measure) I found only one instance of co-eruptive behaviour back in 1440 (Hekla & Katla). With that many eruptions to compare between there should statistically have been slightly more than 2 co-eruptions out of pure statistics only.

    And I was so happy about starting to get riled up by the possibility of a VEI-5 at Katla causing Hekla to blow chunks in a VEI-4, causing a massive rifting at Eldgja which in turn released the pressure over at Hengill so that it erupted under Thingvalla lake (VEI-6), then Veidivötn produced 50km^3 of basalt, and then the entire Hreppar micro-plate blew away to Mars due to Krysuvik being pregnant with bean stew by-products in the worlds first VEI-11… 🙂

    Caveat: For any sensationalist press member, this was wild fantasies caused by a burrito over-load.

    1. No way I ALLOW this ALL to happen at once (in my back garden that is), but really liked metioning of WEI-11 “blowing into space” part !!!!! Suppose it can be used by NASA to “surf” it to Mars?

      1. Sadly that would probably be more likely than NASA sending a space-ship to Mars… *sniffle*

        Happy that I proved that this will statistically not happen 🙂

        I think that one of these days I will write the penultimate catastrophe book ever made (a tribute), where something like this happens, but where a beautifull blond female icelandic volcanologist prevents the final end of the world by using a forgotten american nuke that was lost in a car-crash ontop of Vatnajökull… Of course she has to use Icelands only nuclear submarine (hepp!) to dive into Lake Thingvalla to drop it…
        Logical? No! Fun to write? Heck yeah!

      2. Now you are on really fast track to Hollywood … suppose amend car-crash ontop Vatnajökull, to high-speed “Top secret train-crash” (less likely) at Thingvellir. Guess only place a secret high-speed rail tunnel (UK – Iceland – Greenland – Labrador – USA) to be on surface, whould be at Þingvellir fault … so how about just diverting train directly into the lake or let it hit Hengill Volcano? Consider this Off Topic replay.

    2. You want that the Hreppar microplates blows upwards!!!???

      But, my friend Carl, there’s where my house is located. Shame on you (kidding of course)!

      I do not wish any volcano to erupt within the next two months because I go travel on holidays. It would be terribly sad to know a volcano is eupting back home in Iceland, and me somewhere in Asia. When I return I would be happy by a small VEI3 eruption so that I can go watching some nice and harmless lava fountains at Christmas or New Year’s (what could be best to celebrate entry into 2012 with some lava and northern light spectacle)

      But I don’t wish any Veidivotn or Hengill to blow. That is a terribly inhuman wish to make. Especially when we have so much world trouble. Not even the expected VEI5 Katla. Because that will have a negative impact on Iceland, and also where I live. The thoughts of a Veidivotn-like fissure really scare me, only by imagining those immense amounts of lava and gas coming out.

    1. I got quite cold the last night, we had even frost on the cars in downtown Reykjavik. Its getting winter now pretty fast.

  18. well l’m french and my english is not perfect sorry
    it is the first time l write here
    please take 10 minutes to observe the “cloud” and his direction
    use toggle fullscreen and you will observe on his base a direction from bottom to the top … l suppose it is the beginning of “plume of water” and at all a simply cloud
    ice begin to melt
    l hope you understand my language
    Fabien

  19. This water level drop in Kleifarvatn – is it due to the swarm in the lake the other week?
    Also, was there an outcome to those holes in the road in Sjellfoss a few weeks aog?
    @ Carl – I hope the cam doesn’t go down when your starkers on the top!!
    A thought on the snow on Ejaf – if it was in the UK the gritters, spreading a few kilotons of salt, would be out and it’d be the ‘wrong sort of snow’ for the railways!

    1. I wrote a quite lengthy one on the waterdropping at Kleifarvatn a blog-post or so ago.
      It either started 480 days ago or on the 27 of fabruary. Take your pick. The reasoning behing this is in the other blog-post.

      I totally detest road-salt. Just makes cars rust.
      I will place my new car in my garage for the winter when it comes back from my silly jaunt of setting a world record in speeding last weekend…

      1. @Carl
        Oops pea brain didn’t look a few ago – it’s called age!
        Latest salt here has molasses mixed with it – to ‘help sticking’ dunt half make a mess of cars, horrid to quality test and stinks like ****; hate to think of the long-term environmental effects!

      2. Sounds like that crap would make any anaerobic earth bacteria very happy indeed.
        I have my new car at my house in London and my environmentally friendly electric in Sweden, I don’t know what I was thinking about there… Should have been the other way around.

    1. These quakes weren’t exactly at Skjaldbreiður, but rather at Þórisjökull glacier which is a known earthquake spot in connection with nearby Prestahnúkur volcano.

      2. Is that the latest scientific result? I was never really sure if it was more part of Hrafnabjörg volcanic system, because that’s what I learned at guide school in Reykjavík or rather of Prestahnúkur sytem which I have also been reading somewhere.

      3. I can not even find a Hrafnabjörg Volcanic System… 🙂 But now I have googled it… and found it.
        No, the Skjaldbreiður I was talking about is definitly a part of Prestahnúkur volcanic system, the large shield volcano of Skjaldbreiður was created in one VLE (very large eruption) 7550BC.
        It lies within the SW trending fissure zone belonging to Prestahnukur volcanic system.
        http://www.volcano.si.edu/world/volcano.cfm?vnum=1701-07=&volpage=synsub

        Earthquake we are talking about:
        Wednesday
        21.09.2011 18:10:31 64.519 -20.709 1.1 km 1.9 71.15 12.7 km N of Skjaldbreið

      4. Ah, found the Hrafnabjörg.
        It is a tabletop volcano (Tuyja) of sub-glacial origin. It is today believed to be belonging to the list of either stone-dead or ultra-dormant (depending on view) volcanos.
        It is either a volcano of it’s own, a subset of Hengill or a subset of Prestahnukur. The current vote is that it is a feature of the Prestahnúkur SW volcanic fissure system since it lies withing that geographically.

    2. Prestahnukur is still active, so it might want to attend to the list of future erupters, erupting maybe within the next 10-50 years?

      1. Sorry for typos, our dog puppy Has chewed few keys off my laptop, so writing is a bit of guesswork…

    2. Well, it started at the same time as the harmonic tremor that preceded the earthquakes at Katla. You can clearly see the harmonic tremoring at Slysáalda SIL.
      It is also visible at Snaebyli and over at Hekla side on Haukadalur (but weakly of course). I hypothetically would hazard a minute guess it could be a perhaps maybe something like towards a lateral injection into the Eldja fissure zone…

      1. wait wait wait…

        so the tremor was at Langjokull stations?

        I would like to think that these station detected the tremor from afar in Katla. But if tremor happened at same time in Katla and Langjokull this afternoon, then this is nothing new. Last time a big Katla tremor happened, there was also something big happening at Krisuvik. The though of this being something related to Iceland overall (the plume) creeps me!

  22. hi,

    I’m new here and about to ask some newbie questions. I ran up to this blog thanks to a comment on a weather forum about a possible eruption of Katla due to the harmonic tremor and seismic activity beneath it. I followed this blog for some weeks and you guys seem quite alarmed about a possible eruption. Now my questions are:

    – What is an approximate possibility of an eruption considering the current seismic activity?
    – If so, is there any time indication starting from the quakes starting in july 2011?
    – What was the seismic activity before the previous eruption, if documented.

    Thanks for any response.

    B.

    ps: nice blog

    1. 1) Not even the professionals can give you an accurate figure. They’d probably say that Katla most likely will erupt within the next 100 years or so and consequently say that the chance of an eruption within the next 12 months is 1/100. Since there is no way to say for certain, she might go next week but could just as likely delay until we’re in our graves and our great-grandchildren are wizened and gray.

      2) Katla has been quaking for decades. The monitoring equipment has been getting better and is more plentiful nowadays, particularly after the Eyjafjallajökull eruption of 2010, so it seems there is more activity this year when this is not a conclusively proven fact. Since the vast majority of quakes are shallow, common thought is that there is an increase in hydrothermal activity (in turn due to magma rising from the astenosphere). Very few quakes indeed have been deep, i.e. there aren’t that many signs that point to a large influx of magma, hence there aren’t any clear and unequivocal signs that an eruption is imminent. Then again, you never know for certain with volcanoes.

      3. Since the last confirmed eruption of Katla was in 1918, there really isn’t anything to compare with except what you might find by googling for verbal descriptions of that eruption.

      That said, welcome and please join the long watch!

      3. Now this is a fascinating clip. So much information for each area I could spend hours re-running it!

      4. If you are reading German or Icelandic texts there would be this book relevant about Katla – especially concerning verbal discriptions of the 1918 eruption.
        Werner Schutzbach: Katla : die Geschichte eines isländischen Vulkans . – Reykjavík : Lafleur, 2005 (German version)
        or
        Werner Schutzbach. Katla, saga Kötluelda. Lafleur. Reykjavík. 2005. (Icelandic version).
        I was looking also for an English version, but couldn’t find it. Perhaps there is one, too.

    3. Sad thing though is that this really put into perspective the amount of light-polution that we emit… No wonder they have to send the observatories into orbit.

  24. @Carl and Jack.

    Re: Gravity Data

    I can’t find anything really enlightening (to me anyway)… but this is the best I can find.

    The issue is in finding data with a high enough resolution to be of much use. The Gravity Recovery and Climate Experiment (GRACE) does have some data that may be of use… but everything is in 1 x 1 deg points. At least it has more recent data available rather than some bucket of points from 1964 sitting on a shelf somewhere in a dusty basement.

    I picked samples from Sept 2010 and Sept 2011. That’s only 16 points and is spread from -18.5 to -21.5 (longitude) and 64.5 and 65.5 (latitude)

    They are on the same chart for comparison.

    If you can make something of it, more power to you.

    http://i52.tinypic.com/30jti81.png

    1. My lay interpretation, is that overall, gravity has declined in the area. This could probably be explained as a lowering of the density of the rock column. Heat? Magma upwelling? Dunno. Of note is that the northern points (65.5°N) have a greater spread after one year, with 65.5°N 21.5°W having the greatest change.

    2. I really wish they had at least 1/2 degree resolution. Nothing south of 64.5° was available (as land) and the data slewed up to the default “no data” value of open ocean.

      That Northern (with the greatest change) is on the far North Western part of Iceland. To me, that seems a bit backwards. I would think that the southern realm would have the most heat build up… that is if I’m reading the data correctly. (I give that a 50:50 chance)

    3. Given the weakness of the gravity (as a natural force), it’s very hard to measure those minute differences. Also, the results depend on the chosen reference frame. Hence, basically we’re left what you have already found…

    4. Something is just plain wonky with the data…
      First of all, we all know that Iceland is known to be 50 metres up from earth normal, the way they proved that was through a combination of inSAR and gravitometrics, ie. Iceland has a higher than average gravity. So there is just no way Iceland can be having the negative G-values that is shown here.
      The lifting is higher in a line running from MAR to the hotspot.
      The only reason I can find for the lowered gravity would be if the crust under Iceland was made of lighter then average materials, which it is not. Rock weight in Iceland is ranging from intermediate via heavy to some ultra-heavies where the hotspot has crept forth.
      To be blunt, the data here does not conform to any other data I have seen for Iceland. There is actually quite a bit of bouguer-mapping of Iceland, problem is just that there is non for the Krysuvik area, that is my problem. *sniffle*

      Good plotting on your part though!

      1. Thats the other problem those numbers are not G values. They are gravity anomaly in “equivalent water thickness”, and I don’t even know what it is an anomaly from… ie. the reference.

        That “pile” of data wasn’t the easiest to digest, and the Potsdam version of it I had to throw out after getting it. (pure binary) Luckily JPL allowed you to select your output format.

  25. What are the chances that we could see a fissure-style eruption from Katla? Not wishing for it, just wondering.

    1. Your guess is as good as mine.

      The 1755 eruption was a fissure one; many contributors have commented that some of the earthquake activity is near or pointing to the fissure site in recent earlier posts.

      But your guess is as good as mine. You do not want to see a 1755 style eruption – it would not be good for N Europe, we could have some global cooling and it could be devastating for areas of Iceland.

      1. Nitpicking: all eruptions of Katla are socalled fissure eruptions. What you are referring to are the flank fissure eruptions. The last time such thing happened with Katla was in 934 A.D.
        The 1755 was a ‘regular’ intercaldera eruption.
        What the chances are for a new one? No one knows, simply because we lack any data on the precursors, regularity and characteristics. Plain logics would indicate that there so far have not been any clear signs of magmatic processes outside Katla caldera. (with the possible exception of Godabunga, which is a case on it’s own)
        One thing is sure; we need earthquakes, lot’s of them, before anything starts at all.

      2. The mess with the classification of the eruptions could be due to lack of a simple definition. I have not seen any other definition for a fissure eruption, than that given by Wikipedia ( http://en.wikipedia.org/wiki/Fissure_vent ). And I do not like it! It relies on the visual observation of the shape of the vent. If the vent was hidden, e.g. under a glacier, determining the true nature of the eruption is more or less a guess.

      4. I found your post on September 6, 2011 at 09:14 here: http://icelandgeology.net/?p=1429&cpage=1#comment-18433

        However, I can not see, how you made the distinction, as there is not enough information on that page to justify your division / classification. Would like to clarify it more?

        I see mainly explosive subglacial eruptions. Only three eruptions are listed as fissure eruptions, namely 1823 (arcuate fissure), 1755 (radial fissure eruption) and 934 (regional fissure eruption). In these cases, also Katla proper erupted with the subglacial explosive eruption.

        Just remember, I’m an amateur, too!

  26. Does anyone know the precise date of the 1918 Katla eruption? & did it precede the 1918 ‘flu pandemic? If yes, would the fall out over N Europe have exacerbated / mimicked ‘flu symptoms (bearing in mind that testing for flu then was not as sophisticated as it is now).

    1. The 1918 eruption started on october, 12. I haven’t actually read anything about fallout in europe, but there might have been some. What do you mean with “mimicking flu symptoms”?
      The 1918 flu had a very quick onset, very high fever within a few hours. This is nothing what will be caused by volcanic ash.
      Regarding the testing: There was none. The human influenza virus was discovered in 1933.

      1. Katla had nothing to do with the flu in 1918-1919 or the cold winter in 1918-1919.

        The eruption started in 12 October 1918.
        The pandemic started early in January 1918 and became widespread in August 1918 (before the eruption)

        Also, the winter in 1917-1918 was extremely cold (look here http://www.semp.us/publications/biot_reader.php?BiotID=637), so the cold climate was actually before the eruption, and probably helped as a factor in the pandemic, as well as WWI which was then finishing.

        In summary, Katla eruption in 1918 did not cause any climate impact, or any effect in the pandemic.

      2. Also, Katla not only had NO effect in the climate, in 1918, but also NO effect in 1755.

        Read here: http://booty.org.uk/booty.weather/climate/1750_1799.htm

        The eruption happened in October 1755. The Winter of 1754-1755 was a very cold one, as well as the following one. Apparently, the eruption did not change anything in that cold period.

        The cold was before and after the eruption. No impact from the eruption.

        Sorry to let you down. Only Laki in 1783 had a clear climatic effect (and that was because of gas, not ash).

      3. So, even the largest eruption of Katla of the past 1000 years (1755) had no impact on the weather.

        But Laki had a clear and major impact, as you can read in the historical descriptions from the following years here http://booty.org.uk/booty.weather/climate/1750_1799.htm

        The only other eruptions that could have had a minor climatic disruption were Hekla in 1104, Oraefajokull in 1362 and Veivivotn in 1477, but the historical data is not clear for these events. Probably, if they had an effect, it was much smaller than for the Laki event.

    2. 12 october, for 24 days
      However,don’t forget it was after WW1, poor food and gas in the trenches
      Bed time now, good night folk!

      1. The spannish flu started on the 4th of March in Fort Riley, Kansas. The first victim was company cook Albert Gitchell.
        Later evidence though sugests that the virus originated in the far east as a normal flu virus of the H1N1-type (same as we’ve had the last couple of winters) and that it mutated in a swine-hearding village adjacent to Fort Riley. There is a marked peak in deaths in that village during the weeks running up to 4th of march outbreak in Fort Riley (522 cases within 5 days).
        Even though the death toll was unusually high for a influenza it was not untill august that it mutated yet again into the deadly version known as the “spanish flu”, that happened in Brest, France.
        Early 1919 the virus just disappeared. Probably due to being to effective so that pretty much everyone on the planet that could get it was immune by then.

        The reason for the deadliness is not the war, it was the virulence of the virus. The highest recorded mortality was in the pacific ocean where a sub-strain had a five time higher mortality than average european. One example eradicated 1200 islanders and left one old lady.
        The symptoms where also totally different from normal flu. First rapid onset of very high fever within hours of first starting to feel sick, massive glandular swelling, cytokine-storming then started to fill the lungs with fluid and in many cases black lumps formed on the throat and in the armpits. Ie, the victims drowned.
        The pattern of infection was also different, it mainly killed people in the ages of 16-30 due to their immuno-defence system being strong enough to cause a deadly cytokine-storm.

        Or in more mundane words… It was a bad momma of a flu.

        Spent my idle married years listening to my ex-wife who pretty much wrote the book on H1N1 influenzas. She might have been the only one who was happy in her little researcher ways when it returned… After all she had patents on its genetic sequencing…

      2. What killed the victims in the end was the massive over-reaction of the immune system. This was also called “cytokine storm” by one of the researchers.

      3. There is much evidence (some very recent) to suggest that secondary pneumonia was also a substantial factor in the mortality rate; the ‘cytokine storm’ and epithelial cell death allowed bacteria to take hold, along with some other significant factors in terms of immune response (virological infection increase susceptibility to secondary bacterial infection) which meant that the body’s bacterial defences did/do not kick in as they should; hence what little forensic evidence of H1N1 from 1918 there is shows a near 80% signature for presence of aggressive pneumonia co-infection.

        Better stop there before I go way off topic (this is my field too – Carl – be very interesting to chat to your wife!! Presumably she is also working on H5N1?).

    4. Karen, the twin reasons why this flu was so deadly are 1) Europe had been at war and most populations were under- and malnourished, reducing their resistance to microbe invasions, and 2) this most likely coincided with a new strain of the influenza virus.

      If you go back to the Tambora-induced “Year without a summer” 1815, the effects on the population were worst in Europe because Europe had been devastated by 20 years of warfare, the Revolutionary and Napoleon Wars. Again, malnourishment exacerbated the effects of that volcanic eruption.

      1. The 1918 strain was new (H1N1) and both highly contagious (there are estimations that around 50% of the entire world population of that time where infected) and had high mortality (around 2% if I remember correct). All three facts together make it a real killer.
        We can be pretty glad that the avian flu outbreak two years ago (AH5N1) had only two of these features: Beeing new and highly contagious. Otherwise there would have been a really serious outbreak then.

      2. The avian flu outbreak was not that severe (weorldwide), as the virus was too good in kiling the patients! If you think about it from the evolutionary point of view, the ideal flu virus would have 1. very efficient spreading machanism, and 2. does not kill the host too soon (to help spreading). Some experts claim, that if the patient is killed in less than a week, is will make spreading much harder, and the epidemia more or less local. Those same experts have said, that a killing time of two weeks or longer wouyld be ideal to cause a pandemic.

      4. Forgot to mention one thing: All these HxNy viruses are simply A-viruses. And, the A-virus is the only virus capable of living in and infecting all mammals. Cow flu, horse flu, etc. have been known for a long time. The recent strains are however the first for a long time exhibiting both spreading capability from one species to another, and with a significant killing rate.

      5. Think you meant pH1N1 – H5N1 is still only efficiently transmitted to poultry but is very deadly to both birds and humans (although vaccinated poultry are becoming silent carriers – v.v. bad). pH1N1 (aka swine flu) was highly transmissible but a very close cousin of 1918 H1N1 so there was a significant amount of residual immunity (there was a 1918H1N1 accidental release in the 1970’s) but truthfully, we are all still scratching our heads as to why it was not considerably worse, even so; the disease aetiology and infective processes of swine flu and 1918 flu are very very similar. Whilst it was mild in the majority, the deaths were concentrated primarily in the under 40’s (about 50% were otherwise healthy i.e not in any at risk group) with almost no deaths in older age groups.

        Right now the thing planners etc fear is a reassortment between pH1N1 and H5N1 – both of which are circulating widely in Asia and both of which infect pigs quite easily 🙁 As I said before, not good.

      6. Correction for clarity – the accidental release was from an immediate descendant (1933 variety) and not the original spanish flu.

      7. Good you pointed that out.
        The 1918 version was not in existance untill my ex thought it was a good idea to re-make it from a dead body found in (if I remember correctly) northern most canada that had been in permafrost, and a sample saved from an autopsy made in Fort Riley (have not a clue how she got that sample, but she had it in a -80C freezer at home for a while…). From those samples the infamous genetic re-construction was made. She also was a firm believer in collecting every known strain of Marburg… Not good for sleep.

  29. Suppose so….
    Can somebody explain me what it means an increasing in red frequency??
    As far I saw here that blue and green are increasing with environmental movements as man work or wind, but in older post the red is linked to magma.
    And I consider the regular increasing not picks from here and there.

  30. Bit of fluctuation overnight between HVOL and GOLA regarding GPS, sorry I don’t have before and after screenshots, it looks like they completely switched places regarding readings. The weekend is coming…

  31. Apologies if this has been asked before, but is the sensor for conductivity sometimes above water level and therefore inert, as regularly the readings are offline? I’m talking specifically about the Mýrdalsjökull: Múlakvísl; V089 charts.

  32. Wish I was in Iceland right now (as usual) what a magnificent day it is there, and a little here too in Glasvegas.

  33. Wow! Both Eyjafjallajökull and Katla look absolutely magnificent today with a fresh layer of snow and no cloud to hide their beauty. I hope nothing happens to mar that pristine look with a covering of ash. At least lets have a few months of their beauty.

  34. Gorgeous views of both volcanoes.
    Interestingly, there is steam rising from the waters flowing from Eyja’s glacier (Gigjökull). 🙂

      1. Looks a little like the edge of a weather front, brighter blue ahead with thin high cloud behind.

  37. Jack, to explain in a sort of mental shorthand:

    1) Constructivism, we build explanation models based on previous knowledge that get more refined with advancing knowledge. I’m at the stage where I believe that what we see on the surface is rather a surface expression of what goes on below rather than volcanism proper (i.e. basaltic fissure + water = explosive, no water >> gentle Hawaiian)

    2) What rises from deep below and drives volcanism is basaltic magma. If there’s an eruption from such an intrusion, it can either be in the form of a fissure where the magma reaches the surface more or less unaltered chemically or it can encounter older and fractionating magma in a “magma chamber”, energising it, remobilising it and (to some extent) mixing with it which results in the spectrum andesitic-dacitic-rhyolitic. In the former case, the eruption is only explosive if it encounters water, in the latter almost always violently explosive and – due to remobilisation of older magma – more voluminous. The 2010 Fimvörduhalsi and Eyjafjallajökull eruptions are good examples of these two different kinds of eruption (albeit expressions of the same deep intrusion).

    3) If you look at Katla and ignore the descriptive words and just look at the erupted volumes, there is a gap between what to all intents and purposes can be expressed as 10^8 and 10^9 m^3 eruptions.

    4) My hypothesis is that even if all eruptions at Katla are explosive, they are so because of the 200 – 700 m thick glacial cover and that in reality we are dealing with two types of eruptions whose surface expressions are hard to tell apart. The first type, rarely exceeding 1-2 x 10^8 m^3 I presume are eruptions where the basaltic magma more or less goes straight to the top and reacts explosively with the glacier. The second, much rarer type is where the basaltic intrusion remobilises substantial amounts of old, fractionated magma, mixes with it and produces those relatively rare 10^9 m^3 eruptions.

    If this is not utterly wrong, I’d expect one of those two different types of eruption to occur, either a surtseyan VEI 4 where the eruption column might reach subplinian heights or a Plinian VEI 5 which, since it is less than a century since the last such eruption, would surprise me very much if it reaches above 1-2 x 10^9 m^3.

    To me anyway, it seems that the only hope for those (subconsciously?) wishing for something more spectacular is a regional fissure eruption directly under the Myrdalsjöull icecap, i.e. an Eldgja or Veidivötn type eruption.

    Hope this makes sense?

    1. I think you may have a clue here…

      First, your idea seems to rely quite much on the basic differences of the two main magma groups (interaction with old magma vs. fresh magma). Your reasoning might be correct for cases where the magma chamber is not old i.e. cooled (read: solidified). Then we have this glacier (read: melt water) which makes it pretty complicated to identify the magma source (fresh or mixed). The question is thus: Do we have any reliable information on the magma types involved in the different eruptions for Katla?

      There’s also one weakness (I did not figure out any other word for this, sorry about that): The definition of fissure mentions the word “linear”, i.e. the shape of the vent is important. While it is true that a dike results in a fissure with much higher probability than an erupting magma chamber, can it be said that a circular vent does not imply a dike intrusion (in a sense it did not reach the surface i.e. open a fissure)?

      Your observation about the erupoted volumes with such a clear gap in the range 1e8 and 1e9 m3 is very interesting, and rises many questions in my head.

      Any comments from others?

      1. About your dyke thoughts.
        A lateral dyke can be filled with magma from the chamber, and then erupt in a circular opening, that is how you get the craters in a crater row.

      2. Jack, did you ever come across this paper? http://petrology.oxfordjournals.org/content/45/11/2197.full

        As for fissure, vent, crater – I’m not overly concerned with these as they are but surface manifestations. I am however aware that injudicious use of terms may be a cause of misunderstandings. As far as I’m aware, a fissure eruption implies is that magma has found a fresh route to the surface, a vent is a loose term covering almost every form of outlet from gases to magma with the added implication that it is, relatively speaking, of small(-ish) size. A crater is a feature that may have started as a fissure, evolved through the vent stage and been a host to either many or explosive eruptions – or both. Or it may have hosted but a single event. Caldera is used to describe anything from very large summit craters to huge depressions caused by the collapse of very large magma chambers. I try to stay within these definitions and if I have strayed, I do apologise!

    2. To “hope for an Eldgjá or Veidivötn type eruption” is leaving aside the suffering such un eruption will impose on all the people living near Mýrdalsjökull site – they will have to be evacuated and as the time for evacuation is with Katla VERY SHORT perhaps be injured or even not make it – and this is just not acceptable.

      1. Húsafell, nobody here wishes for that to happen. But we do speculate about things that CAN happen.

        Regarding Katla, nobordy knows what signs would be before an eruption of the ordinary (1755 & 1918 types) eruption styles. As far as I know the best guesstimate is that there will be enough warnings to evacuate from the eruption itself. Problem is as always those pesky Jökulhlaups, but I think the warning time is 4 hours for those? You probably know that better.
        What no one knows is how a Eldja episode would be regarding to warning signs. As far as known (Laki, story by a local priest) the only sign was immense earthquake activity at the onset of the eruption. Ie, a Hekla style of eruption. BUT, with modern technology it would probably be possible to see signs at least a bit before. At least a few hours since we are talking about copious amounts of basaltic magma running into a lateral dyke creating gigantic harmonic tremoring on a scale never recorded on this planet, and that would still be going on for hours before the eruption started.
        So, no. Katla is not Hekla. Hekla needs 60 minutes or less to erupt. Katla will show signs for weeks or months before erupting.
        And no… I still do not wish anybody to die from an eruption.

      2. Hekla only has short warning because the paths for magma are still open since last eruption was very recent.

        I am almost sure that the eruptions of 1104 or 1947, which were very large and after a long period of dormancy, were proceeded by many earthquake swarms, with at least several days of warning signs.

        Katla will always warn well, and in fact it is currently doing so. No one can complain that was not warned about a future eruption of Katla.

        About Laki, Eldgjá or Veidivotn, there is more tricky. But still I think there would be several days of earthquakes when those large amounts of magma move across the lateral fissure. I don’t think earthquakes would just happen hours before. I think they occur for days before the eruption, and they will be powerful just before it, like it was reported before Laki.

      3. No, actually the 1947 was as quiet as the rest.
        The difference is that it is just a long fissure with a very shallow magma-reservoir keaping the mountain itself warm enough to be really ductile. So it only has a few small quakes as it starts to rip open.
        Think of Hekla as a zipper and the rest as buttoned up. It pops more when you ripp open a buttoned shirt than gently lower the zipper… If you get my meaning.
        One should though never ever compare Hekla to any other volcano. It is the only one of it’s type you know.

      4. Don’t get me wrong, I most certainly do not hope for such a disaster! But knowing humanity, I must sadly conclude that there are those who do – it’s all too easy to ignore and leave out the human dimmension when intellectually contemplating natural phenomenae…

      5. That is why it is good that they have started a risk assesment project. The main reason for them doing it is that Iceland is going into an era of increased volcanic activity, and that they seem to believe that they will have a rifting episode sooner or later.
        In my view, it is better to plan for sooner, than later, because then you save lives.
        Currently though they seemed mostly concerned with Bardarbunga having a rifting episode. They probably have reasons for that, but I think they should not forget the risk of either Katla or Grimsvötn having one.
        The notion that Grimsvötn is erupting a lot and that will stop a Laki style eruption is over-rated I think, since the processes are so wildly different.
        What happens during a rifting episode is not the same as during a normal eruption.
        Basically the tension increases over the ductile area of the fissure zone, it cracks, and when that crack is formed it works as a vacum tube sucking magma out of any chamber it is connected to and “boom”. Yes, it needs a well filled chamber, but still.

      6. So both Katla and Bardarbunga are perfect examples for a massive rifting fissure regional fissure. They have now filled chambers, waiting to erupt. This makes them more likely than others to be the next candidates for the next major fissure event in Iceland, which I think it will be within the next decades. But surprises happen, and Grimsvotn has shown to enjoy surprising people.

      7. Húsafell –

        Suppose that there are bad storms in the area. A tornado watch is issued. Just because you keep glancing nervously to the Southwest doesn’t mean you want a tornado to show up.

        (In the US tornadoes usually track in from the SW. ( an arc from S to W with southwest being the center of that quadrant with the tornado traveling off to the NE. Your specific area may have different characteristics so it’s not a world wide rule of thumb)

    3. You missed a third version of the flood basalts, ie. the gentle ultra-scaled gas rich Eldgja eruptions. The Elgja eruption was not explosive at all.
      Why?
      Fresh basaltic material gets laterally injected into a fissure or a dyke and runs very very quickly through this crack for up to 200 kilometres, when it stops flowing at the end, pressure builds up almost instantly to unbearable level and the entire thing erupts all over at every point of weakness.
      In everything else I kind of agree with you.

  38. How I love this Blog. Such a richness of ideas and exchanging knowledge and questions..
    I don’t have much to add that is very knowlegable, just the occasional light hearted banter or a hesitant idea that may spark during doing the washing or dusting. (My mind never can stay fixed when doing chores)
    One thing that fascinates me. Whenever I make jam (Jelly to those in North America) I watch the convection currents pushing the damson pieces or gooseberries or whatever fruit I am using up back down, but not equal movements sometimes one piece will stay in one place for a while then go off in a different direction. Hard to explain!!. It also creates a frothy scum that does stay on top to a certain extent but always goes towards the sides of the pan. Watching this is so like watching magma coming to the surface in some volcano craters I always feel I am somehow missing some deep scientific significance in what I am seeing.
    Just one of my silly musings. Humour me! 🙂

    1. No humor needed. It’s the same physical process on a different scale.

      And watching volcanoes is like watching a pot boil… on a much larger scale. We are sick for doing it, but it is fascinating.

    2. Brownian motion of berries in a lagrangian P-state of suspension in same-gravitetic displacement fluids.
      I just knew there was a physics term totally devoid of the nice romantic touch of your jam-making… 🙂

      Jack, before you throw a spanner on my head, just making an idle joke 🙂

    3. @Diana – your musings are akin to Newton getting bonked with an apple. You may have some exciting new scientific discovery within your jam pot. I have nothing to add but silly observations in this post, but have learned so much and I appreciate everyone sharing their ideas. Perhaps I shall have a light bulb go off for me one day. Meanwhile, there is an old saying here in the U.S., mostly southern – It must be jelly cuz jam don’t shake like that.

      1. @ Carl and Lurking . Oh! How I love you Guys… You make a well Matured Female feel really on top of the world and bring a smile to her face. 🙂
        @ Carl I have saved that scientific description of jam making. May I have permission to use it to confound my children and husband or use it as a great Conversation stopper! I love it!

        @ Brenda I am still waiting for my light bulb too. Lol! and I love that saying… but I don’t understand it. If jelly is UK Jam what is USA Jam?

      3. @Diana: In jelly, the fruit comes in the form of fruit juice.
        In jam, the fruit comes in the form of fruit pulp or crushed fruit (and is less stiff than jelly as a result).
        In preserves, the fruit comes in the form of chunks in a syrup or a jam.

  39. @ Carl & Henrik
    Cor, I wish you folk wouldn’t keep bringing different localities into things, now had to find about Husafell & Veidivotn!! My old grey cells are working overtime.
    Regarding fissures etc from earlier, we used to refer to sub-surface effects as ‘conduits’ anything from localised -central volcano type – to linear conduits supplying fissure eruptions via injection dykes. Fissure eruptions or fissure vents refered to the surface manifestation of a linear conduit. Its English being confusing again.
    This helped my ferreting about:

    http://www.almannavarnir.is/upload/files/Volcanic%20hazards%20in%20Iceland.pdf

    As an aside, I’ve never found reference to lahars in Iceland, but doubtless there are some.

    1. Well, I suppose you could say that a Jökulhlaup is a rather large version of a lahar. I guess it depends on how much it must be in the water for it to be called a lahar proper.
      I would though say that any eruption under a glacier will cause some laharing in the neighbourhood so that you can call and tell people, “I’ve gotten lahared today mate”. 🙂

  40. I think our revered professors need to add jokulhlaup to the list of ‘secondary eruptive products’, most students know of lahars from S American/Indonesian sites, ask what a jokulhlaup is….. “uuhh dunno” (blank look -ie my neice, geography grad!!)
    @ Diana
    Acid lavas here today – bullace/apple/green tomato chutney time!! Yum
    (I’d use smileys but they never work!!)

    1. I kind of think of Jökulhlaups as insanely large lahars… With a lot of icebergs floating around in them.

      For the smileys to work you need to have a blank space between them and the last letter.

    2. You must be in the UK somewhere. Where else in the world do avid gardeners get lumbered with lbs of green tomatoes? ((smiles))<<< alternative to a smiley 🙂
      also try leaving a space between full stop or last word before doing the : and )
      Last word:)
      Last word space 🙂

      2. Ach Nay laddie, I’m a Wiltshireman living/working in Norfolk who likes Scotch and organic feggies! Not moles tho’, bad enough with the hens tasting everything!

      3. Sorry, I still have a problem finding which part of London I occasionally live in… The rest of The Kingdom of the Isles is a bevildering mystery to me.
        For instance, Snowdonia doesn’t even have an inkling of snow… And I will probably never know why my neighbour goes around dressed like a tasteless cross-dressing version of Bumbledore (Or Gandalf for that matter). Mysteries in life… 🙂

  41. I did my own little homecooking. 1000 kg of apples dried down so that they produced 500 litres of home-squished apple-juice. That is now happily burping away and will produce about 250 litres of 10 percent apple-wine. After freeze fortyfying it I will get about 50 litres of 40-percent icewine out of it, as long as the global warming doesn’t make it to warm that is… I need below minus 20C to make it even freeze well. The colder the better.
    Makes one very warm though when drinking… 🙂

    1. Oh! Do you just leave it outside?I haven’t heard of this. It sounds good.My freezer I don’t think goes that cold.

      1. Yes, you place the wine in a large zip-lock bag outdoors and the you go out every 15 minutes and shake it. That way it turns into a mush since the alcohol don’t freeze. Then you just pour it through a filter, in a pinch a coffee-filter would do, but it is better with something bigger like a not to finely woven tovel or some such, fine netting works to, then place that securely fastened over a clean bucket, then it is just about pouring slowly enough.
        If you forget it outside and it freezes to much, then you just take it indoors, thaw it out, and start all over again.
        The colder, the better and faster it goes 🙂

    1. Initially I didn’t intend to mix up apple wine and hazards in Iceland, but my last comment got a bit lost – in Iceland – in apples ….

      By the way, there have been some comparatively small lahars last year on the south side of Eyjafjallajökull during the eruption period (near the farm Þorvaldseyri, see: http://www.mbl.is/frettir/innlent/2010/06/10/sudurlandsvegur_slapp_naumlega/ – text is in Icelandic, but the pictures are showing well what was going on).

      2. Mmm not in Giggle de gug!
        Sudurlandsvegur barely escaped

        Floods in the morning Svaðbælisá Photo Ólafur Eggertsson
        Considerable vatnavextir have been Svaðbælisá this morning. Water flowed over the water gardens, erected in the night to prevent flood and out of the fields in the area. Culverts under the highway was insufficient and could remember little of the water was flowing over the highway.

        “This is the Middle School case there is no such right,” said Olafur Eggertsson, a farmer in the Þorvaldseyri Eyjafjoll. He said that a clarification and a great clay is in the flood and that it has received over farmland.

        Olaf and the people of Þorvaldseyri says no can do, nature will keep it hostage.

        Police said the Hvolsvöllur great capabilities of the region. Both the police will closely monitor progress and people will be expected on farms nearby.

  44. Been trying to find anything on th eGjalp eruption under Vatnajokull, had a look on Google earth and the area looks different. Anyone know if the satpics have been updated, ‘cos the Grimsvotn area looks much more exposed esp to the east.

  45. @Diana
    Don’t know if you have these, but I’ve just received these from Stanfords Maps

    Geological map Iceland
    Tectonic do

    both 1:600000 scale , £22ish delivered, for the two
    Pub Mal og Menning (Iceland)
    Hours of pouring-over to do

  47. And now it is time for me to haul my tired old body out of my office to a pub for a beer or two and something to chew on so I can get up and on the airplane tomorrow.
    Might not get around untill after the weekend, so have a nice weekend all!

    2. You be safe and have a good weekend also. Where are you flying from and to? I am a very nosey person 🙂

  48. OT: coming here and reading is like entering a well-liked pub, where you “know” the regulars and feel at home.
    (I’ll take a caol isla *s*)

  49. Hey guys, especially Carl

    Look at how Hengill looks today from here Grimsnes, 20km to the east, where I live!
    http://img851.imageshack.us/img851/416/dscn0596c.jpg

    You can see the massive steam column coming from the new drillhole, to the left. To the west, it’s a hot spring that we can see it everyday when the sky is clear and the wind calm. That hot spring has always been there, but the drillhole is now releasing a massive column of steam, that is shooting very high!

    Carl and Jon, any oppinion on it?

    http://img851.imageshack.us/img851/416/dscn0596c.jpg

    1. Well, I guess that explains all the activity at Hellisheidarvirkjun.
      I hope as hell that they wont set off an eruption by their testing. I think they should have done that testing over at Kraflavirkjun since there are less people living around it. But, that is another company…

    1. Actually that is only mediahype.
      They have suspected that neutrinos could travel +lightspeed in their mass-less state for more then 40 years now. So nothing is actually new, except that they might have proven some theoretically known.

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