Answers to the friday riddles and volcanoes in Austria

  • DFMorvan solved the first part of the Name that Lava in a very short period of time. So i guess it was not very hard. I prepared the post in a hurry to provide some weekend entertainment and did not have much time to search around. Sissel and Chyphria got the other two points.

Here is the original image which Sissel detected correctly.

And a closeup shot nearby and from the same link showing the rocks in more detail.

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Volcanic activity in Styria, Austria

Two Geological maps of Styria. The right one by Iris also showing recent earthquakes The other one comes from the best paper on the topic pointed out by chyphria and Kelda .
Some month ago, the question came up if there are any volcanoes to be found within the Alps. The hilly countryside in the southeastern part of Styria is not exactly “the Alps” but it lies very close and it is of the same origin as the Alps. The northafrican plate pushes against the europen plate and this caused the alps to be raised as well as some volcanic activity in Styria. Styrias volcanoes are part of the Transdanubian Volcano region ( Wikipedialink in German) This region stretches from Slowenia over Karintia and Styria to Burgenland and then well into Hungary.

Here is an image of the map found on the german site VulkanLand 
The original map is interactive: http://www.vulkanland.at/de/steirisches-vulkanland/Vulkane/Karte/?template=popup

There seem to have been 2 phases of volcanism. One way back in the Miocene dating back around 17 million years and a later phase in the Gelasium in Pliocene ended around “only” 2 million years ago. The first phase was an acid volcanisim and produced mostly shield volcanoes like the ones in Gleichenberg. Many of those ancient volcanoes were only discovered when drilling operations took place, in the attempt to search for oil. The later phase produced mostly basic Vulkanites and you find old remanants in the countryside mostly in the form of tuff cones. The rest has been eroded over the milenia.

The european plate subsided under the african plate, the rocks melted and emerged through cracks. So what happened then, was subduction volcanism, which can now be seen in many volcanoes of the famous pacific “Ring of Fire”. ( Renatos “favorite!”) One example of the older eruptions is the “Gleichenberger Kogel”. An eruption over a period of 5 million years. Only the peaks of the ancient volcanoes are still standing out in the landscape, the rest was covered up with deposits. If you consider how much of those deposits are needed to fill up whole valleys in between the volcanic cones and this was done in a few million years, it shows how distinctively a landscape changes in just a few million years, especially if you keep in mind, our earth is 4,52 billion years old. So there was, most likely never a dinosaur standing in the exact spot were you now hold your BBQ in your backyard.

Around 40 volcanoes once dominated the southeastern parts of Styria.

The quarry in the “Schaufelberger Graben” needs an extra mentioning because one can find Quartztracyte there, a rarer version of the common trachite.

The rock of Riegersburg is a diatrem an old volcanic vent filled up with Basalt. The outer layers erroded away and only the hardest pieces were left standing.
This Image is originally found in the german paper: Geomagnetische Untersuchungen ...

Riegersburg

Now there is the castle on top in all its glory.

A short hirstory of the “Riegersburg” the castle also called the last bastion of christianity because it never fell to the invading turks: The first castle being built on the volcanic rocks was called „Ruotkerspurch“ named after its building father Rüdiger von Hohenburg in 1138. Later it was extended in Renaisance style. The one woman who had most influence to the apperance of the castle was Baroness Katherina von Galler who made the greatest styrian fortress of the 17th century. Nowerdays the castle is one of the mayor tourist attractions of Styria. People can visit the fortress and some original rooms and get informed about the witch-hunt. The rocks can be climbed with several fixed rope routes.

Schilcher is a rosé wine speciality of souther Styria produced  from the grape variety “Blauer Wildbacher”. It may ony carry the name if it was produced in this region, which is the smallest wine producing region in Europe. Many austrian wines are more acidic than mediteranian wines and so Pope Pius said: “They served a rosé vinegar which they called Schilcher.” Many of those wines may have been rather of little quality in oldern days but the quality improved lots and when i studied in Graz and made excursion to the southern styria wine country, we had some delicious samples of Schilcher. It is very typical for people living in Styria to head out into the countryside in autumn and drink the new wine or the not- quite – ready wine called SchilcherSturm with roasted chestnut. Be warned. Sturm tastes more like a grape juice, is really good but gets to your head easily and does wonders to your digestion.

Papers for further inquiry:

Spica

341 thoughts on “Answers to the friday riddles and volcanoes in Austria

    • I found many ( not all too many) articles saying it was subduction volcanism. Only one that states Europe is sliding under Africa. To my logic sense, it should be the other way round, because of where those volcanoes are situated, but i could not find proof.

      • Subduction volcanism is when one plate goes into another and one is pressed downwards.
        The initial bending started south of Sicilly, but the arch is nowadays further north. The part that is going above the other always get a mountain range, in the case the alpine system. So, yes it is Africa going under Europe.

          • Well, actually, with respect to Eastern Alps, Appenines and Dinarides (on the Balkan peninsula), if I remember correctly, these are all formed by movement of Adriatic microplate, which broke off African plate. The tectonics there are complicated, as the plate is subducting in some areas and rotating in others. The motion of the plate caused recent earthquakes in nortnerh Italy, so if you go back to that post, there’s plenty of maps, papers and discussion there on how the plate moves.

        • The Matterhorn is Africa… Quite above sea level for a subducted plate… 🙂
          If talking of the Africa-Europe collision, I wouldn’t categorize that too simply in “subduction”. If we wanted to use a general term, I’d suggest the whole thing is just a mess, a mush, or a “Bircher Müesli” of stuff that is piled together wildly…
          Orogeny here is not as “simple” as in the Andes for example. And it’s a bit special because of the back and forth with opening the tethis, closing the tethis, opening, closing, and then in a final act crushig aaaaall the stuff together. The history of the alps could actually be compared to a married couple that had its ups and downs, grew children etc… As volcanism at some places could be compared to a one night stand during a summer holiday…
          Ehm, yeah, have a nice start into that week. Hope the rain of northern Europe will definitely find it’s way down to the burning south.

      • Don’t know about that specific location in Austria but as a general rule volcanoes emerge in the upper plate of a subduction zone, caused by the melting of the lower plate underneath as it heats up due to friction; and, also due to the release of water from the ocean plate, which helps the melting as it lowers the melting point.

        Given that the Matterhorn is part of the Apulian plate, I guess the area is very complicated.

        “The Matterhorn is composed of gneiss belonging to the Dent Blanche klippe, an isolated part of the Austroalpine nappes, lying over the Penninic nappes. The Austroalpine nappes are part of the Apulian plate, a small continent which broke up from Africa before the Alpine orogeny. For this reason the Matterhorn has been popularized as an African mountain. The Austroalpine nappes are mostly common in the Eastern Alps.” http://en.wikipedia.org/wiki/Matterhorn

  1. I share the same experience as Spica. When I went to school I was happily thought that Sweden has 3 extinct volcanoes.
    Now that I have gotten a bit more volcanologically inclined I know about hundreds of extinct volcanoes, and that we have a faultline that actually might be active in some sense of the word active. But in school it is still only 3 volcanoes…
    How on earth they missed the volcanic fields of the Kiruna ores, and the Skellefteå field is rather beyond me.

    • Thanks, i know why it happened in Austria though. It is/was not visible. Only once they started drilling, those volcanic results emerged.

  2. Nice post. Having lived in Austria twice, this is a regard to read.

    Well, if you want to really go deep, almost everywhere in Europe where there are significant mountains, there were volcanoes in some distant past. This applies for UK (linked to north atlantic volcanism which is linked to Icelandic hotspot), Sweden, Portugal and Spain (linked to distant past atlantic opening and nowadays due to proximity to plate faulting), Italy of course, even some active ones in France and Germany (but in Germany its a hotspot), the ones in Austria and Greece (subduction of African plate)… etc

    And no volcanism in recent million of years in other places in Europe, equals no mountains, Netherlands, Belgium, Denmark, Estonia…

    What is the volcanism in Sweden linked to?

    • The volcanic zones in Bergslagen and Skellefteå volcanic field is very old. The same rock structures are the same that exist in Canadas copper ores.
      The Kiruna field is younger (relatively speaking) and contains massive Fe-ores of magmatic origin. The Kirunawaara mine is the world largest underground mine in volume. It is basically a large Dyke intrusion some 4000 by 250 meters wide and running down to the magma chamber at 2.5 km depth that is believed to contain 2000 times more ore than the todays mine…The mountain was pure iron ore from the eruption, after the mountain was gone they have dug down and down and down… Now they are at 1300 meters depth.
      The volcanic field are filled with two types of Fe-magma ores. One is hematite, and the other is magnetite. Both of extremely high quality. The origin is not well known, so here is what I believe to be the origin.
      I think that it all started as an extremely deep hotspot or other upwalling of iron from the lower mantle, or even the core. That is the only explanation I can think to be correct when weighing together the extreme purity, the insane amount, and the multitude of vents. Also a high UrTh count is found in the area.
      Regarding amount of known or inferred ores. The Kirunawaara/Malmberget ore field contains enough high grade iron ore to cover humanities needs for 250 000 years. And that is the known part. So, iron is one thing we will not lack. Ever.

      • The Baltic shield is not entirely correct. The Bergslagen Skellefteå fields are as old as the shield. But the Kiruna volcanic field is younger.
        For the rest, the Scandian mountains are very old.

        Personaly I am not a fan of the baltic shield. It implies that it is a large area covering the entire baltic region. It does not. Sweden is for instance separated by a faultline from Finland. And that faultline is slowly becoming a subducting faultline as we are being squished into Finland. Give us a few million years and we will have volcanoes again.
        The high coast is actually lifted doubly, both by subduction and by glacial rebound.
        Ontop of that we have a highly active faultline running just north of where my ass is parked right now. That are should be called a formative back-arc, but since we lack geologists interested in things like that… Well… But I have a friend who is a mining geologist, and he is a firm believer that I live close to a forming volcanic line. His ETA for the volcano is within the next 500K years. I did not really believe him before, but now I do.

          • Yes, we also have apple trees that give grapes. But they are too sour to make wines out of…

            For the rest of the planet. Apples here are really small, and all but inedible due to be to sour. Wrong climate.

          • I make Icewine from it. Cider becomes to sour really.
            Icewine is when you make applewine, and then you place it into a zip-lock bag and let it freeze on a day when it is colder then minus 30. Once every half hour you squish the content up. In the end you will have something looking like a slush. Then you filter it and throw away the ice. The remainder is 40+ percent of strongly appletasting liquor.
            Whoever needs heat to make booze?

          • Icewine in Slovenia is something different: it’s when you leave the grapes on the wine long into the winter, until they have frozen and shrunk and then you have an ice-harvest sometime in January or so, that gives the sweetest wine you can imagine.

          • Drawback with global warming, nowadays it is rare that I can make it. I have a lot of bad sour applewine stored for when the temperature will go below -30C. 20 years ago we had two sollid months of -30, and every winter had downs to -40 or -50. Now it is 5 years since we even had -20…
            So, I guess I will have to find a deep freeze soon to make another batch of it.

        • As there are not too many mountains in the Netherlands, the Dutch take very good care of them. The 2 km layer which with great precision has been applied upon Zuidwal protects the mountain against further erosion, so it will last for a long time! 🙂

    • In Germany, the Kaiserstuhl is also linked to the Horst-Graben between the Schwarzwald and the Vosges (in France). Just meant to underline the image of the beginning of a process separating continents. Beautiful… 🙂

    • Skåne in southern Sweden also have lots of volcanoes, active in Mesozoic, ~80 – 200 Ma. They are positioned at the intersection of the N-S Protogine Zone and the NW-SE Sorgenfrei-Tornquist Zone. In an area of 30×35 km more than 50 basaltic necks are exposed and atleast as many has been identified from geophysical data. Two outcrops of tuff has been identified and several other in diggings and boreholes.

      They are linked to reactivation of these faultzones due to different reasons. So far three pulses has been identified and are probably due to the tensional stress in NW Europe, rifting in the North Sea and opening of the North Atlantic.

      I have no more than 15 km to this area, so I find it of course very interesting. 🙂

  3. Well, we were speaking about magma plumes not so long ago.

    I’m trying to fing a way to do some isosurfaces of the EQ swarms. Doing this I found this little video from Joerg Schmalzl. It’s shows thermal convection at a Rayleigh number of 8*10**6

    As soon as there is a dimensionless number around my ears are pricking up (yea I know it’s weird…), so from wiki

    the Rayleigh number itself may also be viewed as the ratio of buoyancy and viscosity forces times the ratio of momentum and thermal diffusivities.

    Enjoy

    http://earth.uni-muenster.de/~joergs/movie8e6h.mpgerg

  4. Speaking of complex subduction areas – what’s the deal with the Himalayas? From what I understand, the Himalayas are a unique convergent zone where neither plate wants to go under the other, so they just end up pushing each other upwards?

    That being said, there is no way this can last, something has to give at some point, right?

    • The interesting part is that they are folding against each other, and the contact point seem to be very stable. Another interesting part is that the are also being countersunk, not only lifted up, so the Himalayas are also a deep sink of crust.
      I see no reason for them to become a normal faultline with one subducting under the other. If memory serves there used to be an even higher zone like that in the eastern part of the US, it did not end untill that part of the world was separated again.

      • Along that same thought…

        My opinion is that the Persian Gulf basin, like the Ganges plain and Indus River valley, are caused by the flexing of one of the plates in the continental – continental collision. The area around Jabalpur is on top of the forebulge, while Delhi is in the depression area of the Ganges plain.

    • Cbus20122 says:

      That being said, there is no way this can last, something has to give at some point, right?

      Valid observation. But you are thinking on human timescales. The Alps were as high if not higher than the Himilayas… they eroded down and became the gravel and gravel like deposits to the north. Some covers the valleys and areas between the Austrian volcanoes mentioned in this post. The Ozark mountains at one time were connected to the Appalachian mountains, that range was also as tall if not taller than the Himilayas. The erosion from that became part of the sediment fill for the Mississippi embayment and now tourists frolic on the silica from those mountains. (sand).

      “It has to give” well, it does. Here are the results of a plasticine experiment as presented in Global Tectonics 3rd edition. They slowly rammed a piston into plasticine to see what fault structures and deformation took place.

      As you can see, it fits pretty well with the way that South East Asia seems to be squirting out from the slow collision of India. Many of the major fault systems show up in the plasticine model.

      In an issue of Scientific American… back when they actually had some science in it before the political agenda crap of today, they had an article which mentioned that one possible reason for the lofty heights was the high speed of erosion on the south side of the range from the monsoon rains. There was also mention of a mid crust level layer that seems to be driving north under the Tibetan plateau. Below the layer, the movement is south, as is the layer on top.

      If you pull up any of the whole earth programs such as Google Earth, then sit back and look at the apparent flow lines of the geological features, you can see that the plasticine model appears to be dead on the money with the way that it turned out.

      As you mentioned… “It has to give”

  5. And here is another prognosis.
    The spam is increasing at an alarming rate, this month there will be about 50% more spam then legitimate comments. If this continues we will at the end of the year have 20 times more spam then legitimate comments…

    • Spam is a huge problem. I run my own company and recently spam has been so bad that maybe only 5 out of every 100 emails are legit. So do I change ISP or do I change web host site, what do i do? it is a major problem for a small business like mine. To change everything is such an upheaval, taking a lot of time, effort and money, it is hard to know what do to for the best.

        • Not a bad idea, Akismet is really kick-ass. It misses about 10 a month out of 11 000 spams and coments. 9 out of those are people linking to EMSC-CSEMs quake-lists.
          I though guess that Kelda operates a company below the “having your own mail admin, tech guy around” level.

    • Yes, but Akismet is doing a very decent job on sending spam to the dungeons, so, so far so good, in my opinion…

      • Is that just a blog spam filter or can it be applied to a website using any web host such as fast host for example? Sorry I realise this question is more appropriate on a tech forum, but as Carl brought it up I thought I would comment anyway. Will drop it now. Thanks.

      • Yepp, our veritable Dragons Galore together with Akismet keap almost all nasty things out 🙂

    • Yes, they are saying that, but – as far as I understand that – just regarding data about the river Múlakvísl and the access to them is locked on that page.

      But if someone would like to see data about Múlakvísl, best is to go to http://vmkerfi.vedur.is/vatn/VV_Frame.php?r=20605&load_graph=1&direct=1&station_id=218&station_name=Su%F0urland&page_id=270 .
      If that is not directly possible, then go to Veðurstofa Íslands – Forsíða – Vatnafar and go with the cursor to one of the rivers , eg. Múlakvísl. – allow access –
      To your left, you then have the rivers (= pages) and the regions/sites. And it is possible to see eg. the conductivity there (= (raf)leiðni). Múlakvísl eg. is in region / site Mýrdalsjökull.

  6. I´m hoping the sheepy bar is still open and that way off OT topics are still allowed…Spica I loved the post very interesting thank you very much. I still think I should have got a quarter point (0.25) for my beverage suggestion seeing as it gave such amusement to some… 🙂 Anyway looking at the papers you gave a links to a saw one in particular- ■Das Eruptivgebiet von Gleichenberg in Ost-steiermark by Artur Winkler – it reminded me of Fonzie, or “the Fonze” that I used to love on the TV show years ago – what what it called “Happy Days”? and wasn´t his real name Henry Winkler, and his screne name Arthur–gosh I must be getting old and senile, when these old memories come back at the slightest prompt..

  7. OT Alert… you can thank Renato Rio. 😀

    He got me to ruminating on that hurricane and levee thing. I’ve lived within 250 km of the Gulf of Mexico for most of my life… half of it within 20 km. As such, I pay attention to hurricanes and tropical storms. Anytime I get a chance to learn something new about them, I usually do.

    Here is a plot that I made up four years ago that allows you to estimate the range of wind speeds from the central eye pressure off of a hurricane report. It’s based off of all storms listed in the HURDAT file that NOAA has. It’s one of my early plots using nothing but Excel and the limited curve fitting routines that it has. Those poly curves of the SD are just there in order to get an idea of what the storm could do.

    But… about that storm surge thing.

    Locating max reported surges for the different storms is a bit difficult to locate. Usually, you wind up at some NOAA site that gears it’s data towards specific sites and the SLOSH model. If you get a chance to go find those, they are pretty cool.

    Storm surge is a result of two major factors. Wind speed and storm mass. Using the American Practical Navigator, (BOWDITCH), you will find that wave height is a function of wind speed and fetch… or how the distance that the wind blows along the surface of the water. In BOWDITCH you can find the formula that will pretty accurately predict the wave heights. As for storm mass… well, they do have mass. The Low pressure in the middle of the storm tends to lift the water, and the mass of the storm tends to push it along. Combined, the storm movement and wind speed place the highest surge on the forward right quadrant of the storm. For Gulf storms, thats usually the Northeast quadrant. Aussies will see the opposite effect… but just as apparent.

    Well, with quest in hand, I hit paydirt. Two Louisiana State researchers have been combing through various historical reports on maximum observed storm surge. Using their web interface, I was able to pull out data for about 34 storms that made landfall along my little section of the Gulf of Mexico… more accurately, from Grande Isle LA to Panama City FL. Using that data, I made this:

    It’s the normal curve that describes the distribution of max observed storm surge for this region. I’ve labeled a few of the notable storm so that you can see where they sit in relation to the group as a whole.

    One thing to note… New Orleans did not feel the full brunt of Katrina’s storm surge… nor did it feel the full brunt of Camille. Betsy had a greater surge in the New Orleans area than either one of them.

    One thing I did not know, was that in 1915, there was a measured storm surge not far from the Betsy reading that was almost two feet higher.

    Like I said.. it’s not like they didn’t know it could happen. Both of those (Betsy and the 1915 storm) are still withing the 3 sigma range, so they aren’t really even good examples of Black Swans. That uh… sort of means that the people driving the show in New Orleans are full on idiots.

    Yes, I said that. Idiots.

    Only idiots of this caliber would leave the population sitting around and not evacuate… even though they had plenty of resources available to get people out.

    • You’d think they would be well prepared in a place like New Orleans. Imagine what the rest of this country could face. Scary stuff. I live pretty close to the NMSZ, but they at least have drills “just in case”. For whatever that is worth.

      • I read that. It was a pretty cool article. Seems that they were able to decipher the waveform and watch the quake traverse the different fault structures.. even into a region of compression. (not something expected)

    • With the NMSZ… the key thing is to get out of the building and away from masonry structures. Grab your surfboard and ride the sand blows. 😀 (kidding)

      If you live in that area, sand blows can be fascinating things to “study.” As you probably know, they are the result of soil liquefaction in the underlying strata that the broach the surface in a spray of sand and water.

      They are evidence of past really nasty quakes. How far away from the quake that causes them is up for debate, but generally they have to be fairly near the intense shaking.

      Via Google Earth, I have seen what appear to be sand blows far to the south west of the NMSZ proper.

      And since you live there, here is one of my old plots of the geologic structures of the area.

      The hatched areas are locations and extents of what are believed to be plutonic emplacements. Red and green lines (and dashes) are fault systems.

      • Thanks for the plot. I am actually about 72 miles southeast of St. Louis and 100 miles north of Cairo, IL, which as you know is the far northern edge of the NMSZ. But, if it goes big, I’m sure we will shake pretty good. And, yes, I do have earthquake insurance on my house.

    • I remember reading an article about New Orleans and the dangers posed by an hurricane a couple ( 2 or 3) of years before ‘it’ happened here in Oz

  8. *sigh…. continuing.

    One of Taleb’s definitions of a Black Swan is that it is rationalized away as having been predictable “if only we had known.” Okay, I’ll buy that.

    But my issue with it is that even if you know the threat it there, are the costs of preparations for it justifiable? Can you convince the people paying for the pre-mitigation to fork over the money?

    Until the “event” occurs, whoever did the convincing will forever be seen and ridiculed as a fool. When the “event” occurs, they will be held up as a hero.

    So… we have all heard about the Fukishima Plant. This plant had a seawall that was put in place to deal with the expected threat from hurricanes and tsunami. It was 19 feet tall. The tsunami blew through it like it wasn’t even there.

    http://www.dailymail.co.uk/news/article-1388629/Japan-tsunami-destroyed-wall-designed-protect-Fukushima-nuclear-plant.html

    So… let’s play a bit with “relativity.” No, not Einstein’s. Specifically, how would the Fukishima Plants sea wall compare to a Gulf Coast Hurricane?

    It is debatable. While the seawall would have performed just fine in breaking up the waves, the storm surge has closer to the effects of a tsunami than a wave. The sea level essentially rises while the storm makes landfall, and any waves that a popping along on the surface are riding on top of that surge.

    Anyway… I’m done with this for now. You may return to your regularly scheduled volcano.

    😀

    • BTW… the storm surge has a much slower arrival than a real tsunami.. the impact of a tsunami is sudden, while a storm surge can take a half hour to rise.

      • Speaking of that… Bagdad Florida is at Exit 26 on I-10. I’ve been through there a few times making my way to Milton via an alternate route. It is located on Blackwater Bay and like Escambia Bay, not directly connected to the Gulf. Everything flows through Pensacola Bay and the pass down by Ft Pickens… 38 km away as the crow flies.

        According to the reference, the 1926 Great Miami storm generated a 14 foot storm surge as it went through here.

        Personally, I find that a bit dubious. Something of that level would have left a bit more than a newspaper account in Pensacola. I have seen large rises in the Blackwater River as the watershed upstream gets heavily loaded, and in my opinion, that is probably what it was.

        BTW, see that Interstate Bridge across Escambia Bay? It’s new. The original was had multiple sections washed out from the waves and storm surge from Ivan in 2004… and downtown Pensacola smelled like raw sewage and fish for three months. (about 10 feet of water downtown.)

        They have since moved the sewage treatment plant further inland.

      • This is the area known as “Ward Basin,” it’s the top part of the Blackwater Bay and just south of where that 1926 14 ft “storm surge” was allegedly at.

      • Local memories of the storm surge that ‘ate’ the end off the pier locally, were that the waves came bigger and bigger – and then came over the promenade – and into the buildings – each wave higher than the last – ripped great chunks out of the promenade and a 50 metres shorter Victorian pier. That was called a once in a hundred year storm – in 1933.

  9. Oooh, I like that.

    “There is no intermediate state between ice and water but there is one between life and death: employment.”

    The Bed of Procrustes – Nicholas Taleb.

      • Heres an On Topic for you.

        According to Bruce Stout over on Eruptions… and Wikipedia, Mt. Ngauruhoe was built in 2500 years. The whole she-bang.

        If my calculations are correct, that means that it has an average annual output of about 4,932,790 cubic meters… in order to build the edifice that fast.

        It falls in the category of things that make you go “Hmm….”

        • “Hmm ………” 😕 or 😯

          “average annual output” means that some years had less and some had more …..

        • Let us now reado that into cubic kilometers. Cubic meters always sound a lot.
          Mt Ngauruhoe is erupting on average 0,004 km^3 per average year. 0,4 km^3 per hundred years.
          Let us now compare that to a real volcano (Yes Mt Ngauruhoe does exist) like Grimsvötn.
          Grimsvötns erupted between 1.75 and 2.25 km^3 during the last 100 years. And that is during one of the low season centennials. If it has a high century it would be 5 to 20 km^3.

          Now you can all go “Hmm…!”

  10. Good morning, evening and G’day.
    We had a day of sunshine yesterday and Saturday 😀 Today we are back to grey clouds but at least it isn’t raining…..Yet!
    Hekla boreholes are doing strange things. Can anyone explain? I cannot put it down to storm conditions this morning as the wind has dropped right down. Is it problems with recording ?
    http://hraun.vedur.is/ja/strain/1sec/index.html.
    I’ll go and make # 2 coffee whilst I wait for response. It looks like a day confined to home so I will hang about here annoying everyone 😀

      • Aw !Shucks! I cannot play in the naughty place as I have stupid disease 😀 😀 :D.
        Thanks Geo I love it!

          • I actually found some… but due to some content that may be offensive to some people i will not include links. 😯
            All power to the great Google. Fount of all knowledge yet carp at international communication.. 😀

          • Carp at international communication? Is that the fish or the beef? 😀 😀 😀
            (Explanation for non-English speakers: Diana actually meant crap. Carp can be a fish or a word meaning ‘complain’ or ‘whinge’. Beef is meat or a word meaning complain.)
            @Diana: Glorious weather here today – that’s three days in a row so counts as Summer! By the end of the week I guess people will be complaining of the heat and wilting plants 🙂

          • Thank you Talla for your interpretation. Google NEEDS you . 😀
            The sun has managed to come out here too and it’s glorious. Pity I can’t get to the allotment today. Never mind at least the washing will dry. 🙂 Hey Ho back to work for another half an hour……..

  11. Brilliant Spica, very educational and exactly my cup of tea (although I’ll have to side with Pope Pius as I’m not a great fan of tart wines 😉 ).

    • Thank you Henri, i tried, and i am very happy even though the post was more personal and not scientific.. an ON TOPIC discussion about european plate tectonics emerged.

    • On the wines, My father used to drink something called “Grüner Veltliner almost exclusively. Not my cup of tea/wine. I was invited to a Schilcher wine tasting ( or whatever that is called in english, and some of those were really good. It was said they were acidic but if i dont taste that, i dont mind. I forgot to intruduce the audience to Uhudler though. And i forgot to mention the Klapotez. A very typical thing there in Styria. But the post would have goten too long.

  12. I would like to start a new discussion here. The Burfell Dalek BBQ could not take place due to unfortunate events, So this menu point is now obsolete. What shall we do with it. Would you like it if we made it something were people could arrange meeting? Another date for the BBQ or excursions or??? Please leave some comments.

    • Splendid idea!
      We should use it for something along those lines!

      (My mind shudders for what kind of new spam we will have with a “dating” section)

  13. Maybe it could be used for meet ups. Also maybe if there is a special exhibition or TV programmes the links or venues could be posted here. I am thinking of maybe Museums or other places that are running something special about volcanoes or Geology that might help students or be of interest to people like ourselves.

  14. Not a cloud here, we finally have summer! 🙂

    It seems quiet under El Hierro. The people on El Hierro are anxious to know if it´s over or what comes next. Perhaps it helps to see if the latest earthquakes are heading in some direction. It´s been said they seem to wander east.

    Here is a rotating 3D plot showing where the last 70 earthquakes (12/07/2012 to 22/07/2012) ocurred in respect to the previous swarms. All earthquakes from 01/09/2011 to 22/07/2012 are colorcoded by date and sized by mblg, except for the last 70, they are the big blue squares, later ones are bigger. The 0 km ones are not shown.

    Although the Bob swarm (brownish) and the recent swarm (blue) took different paths, they recently overlapped. I find it noteworthy that the latest shallow ones (15.3 and 16 km depth) were right within the Bob swarm. I have absolutely no expertise to judge if that means anything but I wonder whether that were settling tectonic earthquakes, new magma intrusion into the old feader tube or reactivated old magma, or whatever.

    Now out for some icecream!

    • The icecream is well deserved. Off to buy some shortly.

      No idea what is happening in the recent swarm, except that the larger quakes (>4) tend to be at 20km +/- . Possibly the ocean crust is more brittle there.

  15. Great post, Spica! And a very good idea to bring up more information on the topics of the SDR (Sheepy Dalek Riddle). After trying to find the solution – sometimes for hours – it is pleasant to be so well informed. Thank you!

  16. There was a small (for being there) magmatic movement in Theystareykjarbunga during the quake swarm.
    It was a lateral dyke intrusion at 5.5km depth moving in a line ENE. In most other volcanoes this would have been seen as a large intrusion, here it just caused a few small quakes. This is due to Theistareykir having a rather large magma chamber for being in Iceland. In late december there was a large intrusion for Theistareykir, then the equipment on four SILs clipped out into distortion, something that normaly only happens during a large eruption.

      • If it had been one… But here it was 4 of them clipping, and 10 that was showing large signals. Never seen anything like it, not even during the run up to Grimsvötn.
        Did you miss that hubbub?

        • Nah, the hubbub was in late december.
          Theystareykjarbunga put in the full show regarding harmonic tremors. Thing is that the Icelandic SILs are not put into the “shy” mode. They are dialled down rather hard since when something happens it is so bloody noisy. So if it clips, then it is big. One should remember that neither Hekla 2000, Eyjafjallajökull, nor Grimsvötn 2011 succeeded with swamping the signals. I went “Hmm..!” on that one.
          Theystareykirs little show made El Hierro in full swing look like a tiny 50cc scooter compared to a type 2 Jaguar V12HE with full Compressor/Supercharger at Le Man. It overtopped everything for almost 24 hours, and then ominous silence.

          What really made me go “Hmm..!” this time is that the small swarm at T preceeded a much larger swarm at the same faultline up towards Grimsey.

  17. Uhm… am a confused or…?
    It looks like it is Kita-dake that is erupting and not Minami-dake. Or is the angle really odd?
    If it is Kita-dake I would be worried.

    • It really looks like it is Kita-dake. But that could not be.
      Someone who knows Sakura-Jima better than me who can enlighten us on this?

      For the rest. Kita-dake has not erupted for 4800 years. After that it is the crater of Minami-dake that has been erupting.
      The one closer to the city should be Kita-dake. I have only seen the one behind erupt. And it is also that one that erupts on the GVP pics.

  18. their is coming more i think you can see the building of the white smoke on the right sight it builds up and go than again with a little patience you see it more times i have seen it i think now 6? 7? times

  19. Carl, do you have a pic from last December tremor graps at Theistareykjarbunga?

    It seems its running a little show again. That 3.7 could surely have been tectonic but after this swarm, it looks suspicious since the 3.7 is still within the fissure region of Theistareykjarbunga (although I don’t know of any eruption there), but it’s quite near to our beloved shield volcano.

    It’s the last volcano just as the rifting changes to a lateral transform fault.

    Actually my belief is that Theistareykjarbunga will have an eruption sometime within the next 100 years. (It has been sleeping for millenia already) Why? Because I think we are beginning to see a period of increased rifting to the north of Vatnajokull, similar to the rifting that occurred after settlement along the entire Reykjanes peninsula for about 300 years. We had a large eruption at Krafla in 1720s, a large eruption in Askja in 1875, and then more episodes in Krafla and Askja this last century. In all likelyood, we will see Theistareykjarbunga also have its own rifiting episode (and that will be Laki-size of course).

    • Theistareykjarbunga is interesting, it is the corner of a square of a micro-plate that is twisting. So, the quake swarm is out in what is a micro subductive zone. East of that one is the Theistareykjarbunga fissure swarm, and that one erupted after the 7.2 in the 18-hundreds.
      We know that T has been inflating rapidly since 2008, around 12cm untill now. Probblem is just that there are no good time sequence before that. For all we know it could have been inflating since the 7.2M or even long before that. Theystareykir has a vast chamber, it can easilly take meters of uplift.
      I agree, I think it will erupt “soon”, but I think that I will not be around when it happens sadly.

      Yes, I have screen-caps of it. I will try to find it. But it is somewhere among hundreds… 😦

      I think I made a post out of it thought…

      • I read yesterday a paper of a guy studying the shield volcanoes south of Langjokull, including the famous Skjaldbreidur. They were speaking these shields generally don’t have a chamber but just a series of minor sills that only work to conduct the magma directly from the mantle upwards. I don’t know of studies done for Theistareykjarbunga or for the equally large shields north of Bardarbunga, about how large is their chambers.

        These 3 regions, around Langjokull, north of Bardarbunga and Theistareykjarbunga are all producing large shield volcanoes, with nearly the same volume, and estimated erupted values about 10-20 cubic km.

        I know of your love affair 🙂 with Theistareykjarbunga, but Theistareykjarbunga, Skaldbreidur and Trollandyngja look rather similar in size, with Trollandyngja having the larger lava field around. There are other larger volcanoes still. OK to the west of Langjokull looks even more massive than the former 3, but its pre-Holocene.

    • Actually looking closely at the 3.7 and current swarm, that is outside and 50km away from Theistareykjarbunga. I think this is not related directly to Theistareykjarbunga but just normal Tjornes earthquakes. But that area is not only tectonics also an active volcano with the same name: Tjornes. It erupted in 1868 exactly at the same spot of the current 3.7. But still it plays well in the connection I just spoke of an increase in the north Iceland rifting activity.

  20. Off topic and space weather related: there was also a significant solar event but on the opposite side of the Sun, not facing our planet. That CME / flare was probably very large because it travelled a very fast speed, which rarely happens, and usually this events if facing Earth tend to generate very southern auroras. Unfortunately, not this time.

  21. Hi – just popping into the discussion to report one of my other regular web site visits brought to light a review of probably the last Spanish mainland volcano (Croscat) to erupt. My apologies if this has appeared here before as a topic, but Science Daily published this article today:
    http://www.sciencedaily.com/releases/2012/07/120723095101.htm

    Hope it is of interest. May I place an order for a nice cold, crisp cider at the Sheepy Bar? Thanks!

  22. With all the talk of Theistareykjarbunga and the gang…

    When two sections of crust open up and a rift vent forms, the two sides generally are moving apart. This is “normal” faulting. What comes out and how much depends on the pressure and the size of the opening.

    So… for reference, a look at average displacement from normal faulting.

    WARNING: The size of the quakes that we are interested in are well below the 95% confidence range of the formula, so note that outside of the region, the accuracy of the formula goes down.

  23. Carl, Lurking et al:
    Ever since Carl’s most interesting post about Icelandic hotspot and LIPs, I’ve been reading a bit about the subject. I even bought a kindle edition of a certain John Carman’s work on Plate Tectonics and its cycles, but I think this one is too hard for me to follow and I have tried to grasp a little more from Dr. Oppenheimer’s book, which I happen to have.
    There seems to be many contradictions and a lively debate between mantle plume x plate tectonics theorists.
    What Carl says about Iceland being still as active as the Siberian traps doesn’t match the information I collected, probably because Carl has more sources to get information as well as more knowledge that I do and I feel limited to better catch up with the matter in depth.
    So, I leave here a suggestion that we could go back to the theme, which I think is of utmost importance to understand the mechanisms behind volcanism and earthquakes, as well as about Earth’s history.
    Best
    (But there’s still a missing post on Italian calderas…) 🙂
    BBGN time! (or, rather, BBGM)

    • It’s a great theme to discuss. But please, let’s not make a dogma out of whatever will be the result of our thinking. We can come to the conclusion that due to our reflexions we tend towards one theory rather than the other, but we don’t see through the crust very well and will probably not have hard evidence to underline our “results”.
      We have a lot of wiki-knowledge and wildly gathered info from a large diversity of papers of various quality. That’s extremely cool and valuable. But let’s not try to be so much smarter than those who spent half their lives studying that stuff in detail, and looking for evidence / testing their assumptions in all the realms of physics, mineralogy… and making every perverted analyze of stone and mineral samples one could imagine…
      On the other hand, it’s pretty clear that people here are the best. And we have the sheep’s support.

    • Renato Rio says:

      …There seems to be many contradictions and a lively debate between mantle plume x plate tectonics theorists…

      That’s because different lines of evidence point in different directions… depending on what it is and how it is interpreted.

      And example. Helium isotopes point towards a moderately shallow source for the Icelandic plume. REE (Rare Earth Elements) point towards a deep source for that same plume.

      Which is correct?

      In order to account for both signatures, both have to be correct, but they can’t be. You adopt a wait and see attitude and keep your option open for either one, weighing the merits of any evidence that supports either case.

      And you alway remember that it could be something completely different.

      • What I found especially interesting, (something I had not known before), is the hypothesis that deep subducted slabs could reach the core/mantle boundary and would play an important role in regulating both the activity of convection plumes and of the magnetic field, since there is a relation of the intensity of plumes formation and the magnetic field created by the Earth’s outer core “dynamo”.
        Apparently, these mechanisms also regulate the peaks of continental drift activity. I only wished I could better understand the maths and the chemistry behind the processes and hoped that you guys would help.
        LIP’s are not only made out of basalts and there seems to be lots of silicate materials involved, which, becoming lighter would rise and accelerate the convection processes. And these silicates take part on the whole LIP festival in form of fallen tephra and ingimbrites.
        Well, this is what I could understand, but I’m sure there’s much more to it.
        Cool stuff! Or, better, hot stuff!
        Wiki is very general as to the complexity of the debate.

        • The way I always understood it is that subducted slabs or slab fragments were composed mostly of oceanic plates and the associated sediments and the odd bit of continental crust that possibly got dragged down in sympathy, but generally all the silicic stuff will tend to float around on top. The silicic component that you see in LIPs is probably therefore melted crust that formed above the mantle plume. This also ties in with the rough trend of continental volcanic zones to start off with rhyolite and andesite and when they have almost petered out, end up in monogentic basaltic fields. Now I’ll go and rap myself over the knuckles for excessive over-simplification.

        • I’ve got one idea that I’m kicking around, that is what sort of quakes do you need to open up a rift?

          Suppose that you have a 10km deep Mag 5.6 quake?

          With “normal” type faulting, where each side moves away from the other, that yields a crack about 5.25 cm wide. Usually, the overburden and other strata would shift and fill in the emptied space, but if it were caused by magma intrusion, or if magma is available, it would fill part of that space. Depending on which got there first. Magma, being more mobile would probably win that race.

          The radius if an assumed circular fault face covering the rupture area of 41.69 km² will be about 3.6 km.

          The quake could conceivably put magma within: 10 – 3.6 = 6.4 km of the surface.

          Now.. this is just one quake and the calculations are based off of that Coopersmith paper, and below Mag 5.6 that particular formula looses validity. Additionally, there will be a swarm of activity if something that size lets go… so where how it turns out is anybodies guess. Cascading failure of the rock that results in an eruption or does it just stop since the force causing the quake is relieved and there is not enough magma pressure to force the issue?

          It’s just a mental exercise. (with the help of a spreadsheet and a good paper)

          (Note: Circular because this is a theoretical quake and I don’t want to even try to figure out what sort of ellipse it would be..)

      • I don’t see why they need to be mutually incompatible. Let’s say the UrTh signature indicates a deep source from the mantle/core boundary but other minerals in the same melt suggest it originated from subducted slab fragments.. then this could be explained by a mantle plume entraining melt from slab fragments on its ascent towards the Earth’s surface… or couldn’t it?

        • Yes, it could.

          Lets suppose that a section of material achieves greater relative buoyancy and begins to upwell towards the surface.

          Many many processes in this setting experiane Rayleigh-taylor instability and material on the periphery mixes in with the main column as it moves further along. We see this in solar granules, where you are looking down at the top of the individual plumes, and you see it when a dollop of granadine is dropped into your tequila sunrise.

          It only makes sense that other material will be brought into the column/plume.


          Several calderas exist around the world, a lot of them are in the 40ky to 80ky age range. Is is possible that the events along this region that triggered those calderas was related to the Laschamp event? That being a geomagnetic excursion… maybe cause by a restructuring of the flow patterns in the mantle? Some calderas that lie along the Italian peninsula date to this time-frame, and we know that the subduction regions in and around the area have reversed upon themselves several time. (mainly evidenced over along the eastern Adriatic coast where the “super-subduction” occured)

      • And here is a wild one…
        HE is rather iffy, it is common in the deep mantle, but it is always low to almost non existant if you go beyond that to the boundary.
        Here I am on my own, this is not common theory.
        Thing is that the large FE ore bodies are ultra low in HE of any kind. And those we know come from very large depth, or even the upper core. If I am correct in my line of thinking the Icelandic hotspot is originating so deep that it is beyond the HE3/4 boundary line.

        Caveat, here I am far out on a limb, but the limb is connected to oretypes that I know very well.

    • As I said before, Lucas, you should join FB volcano pages. There’s a lot of these updates over there.
      This one was provided by an Indonesian geologists called Muhammad.

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