Comments to A Tale of Three Cities

Wikimedia commons, Arco Antigua in Guatemala.

Wikimedia commons, Arco de Santa Catalina in Antigua, Guatemala.

Very interesting article!

https://volcanocafe.wordpress.com/2013/05/05/a-tale-of-three-cities/

I’m Guatemalan and I’m doing a PhD studying Fuego volcano, so I was glad to see someone writing about Guatemalan volcanoes and about the risk related to their activity. I do have a several comments about the article, and I hope they won’t be taken as “malicious hair splitting”, but rather to further the discussion about these fascinating ideas.

Regarding the 1541 lahars, I guess nobody knows exactly what happened, but the early chronicles (see Remesal, 1619, and Feldman, 1993 for a compilation) agree that very intense rain happening for several days prior to the lahars, whether there was also an earthquake is not as clear, since references to the “earthquake that came from above” may just relate to the lahar and associated rumbling and shaking phenomena. The simplest hypothesis is that this resulted from an extreme rainfall event, which recur every so many years during the tropical storm season (the event happened on September 11, at the thickest of the storm season), an probably had nothing to do with volcanic activity, and maybe not even with any seismic activity. Recent examples of similar events at Agua include lahars and mudflows during tropical storm Stan in October of 2005, the rainy season of 2006, affecting the town of Palin on the E flank, tropical storm Agatha in 2010, affecting the town of San Juan Obispo on the N flank, etc. All such events only cause a few deaths compared with the 1541, but examples on other nearby volcanoes, like the lahar that destroyed Panabaj, on the flank of Toliman and Atitlan volcanoes during Stan in 2005 shows that such events have the full potential to cause a similar disaster, entirely related to extreme rainfall. But maybe an earthquake also contributed… but this we will probably never know.

The controversy about a crater lake breach is also difficult to settle, but I don’t think there is any good evidence for the crater lake hypothesis. None of the original sources (eyewitnesses) that I know mention a crater lake, although I neither aware of any description of Agua’s summit before Remesal’s account of a climb in 1615. Two other lines of evidence suggest to me that the crater lake breach hypothesis is unlikely. First there is no evidence of lake sediments on the current crater (although the crater is partially filled with colluvial material from the inner walls), suggesting that a long term lake probably didn’t exist within the crater. Secondly, the breach in the crater drains to the wrong barranca, and therefore a crater lake breach probably wouldn’t end up in Ciudad Vieja (or what today would be San Miguel Escobar), it would instead end up either in San Pedro Las Huertas or San Juan El Obispo. As I mentioned before, a crater lake is unnecessary to explain a lahar associated to heavy rain, and for the lack of evidence of such a lake, it seems more likely to me that the lahars were just caused by the collapse and transformation of saturated flank material.

The story of the Antigua moving, first contemplated in 1717 and finally done in 1776, after the Santa Marta earthquakes, is full of political intrigue and power struggles between the religious and civil powers of the time, and the natural events (eruptions and earthquakes) were used by both parties (those who wanted Antigua to remain as the capital, and those who wanted to move it) for or against the move, and in the end the decision was probably motivated by many other reasons than just the obvious “natural hazards threat”, as always, things are more complex than they seem at first. There have been a few very interesting analysis on this, and for an in depth analysis you can read Christophe Belaubre work (http://www.revistas.una.ac.cr/index.php/historia/article/view/1754). In any case the new Capital General, Martin Mayorga, finally prevailed over Cortes y Larraz and the capital was moved!

The volcanological relationship between Acatenango and Fuego is a difficult one to assess, given that we know relatively little about both volcanoes. Geochemically they seem different in some aspects, with Acatenango having some more silicic rocks, but there is broad overlap in compositions.

A plot of the whole rock TAS that I made from the CENTAM database

A plot of the whole rock TAS that I made from the CENTAM database

I suspect that this difference would decrease if we do more sampling of Fuego especially of the older rocks, as the sample dataset may be skewed towards younger products (e. g. 1974), and in general I think that so far we have only scratched a tiny bit of Fuegos eruptive history, this may be difficult because having Fuego been so active in the last few thousand years it may be difficult to find outcrops of older rocks.

I did not understand the comment on the blog stating that “some researchers have extemporized that the magmatic system of Fuego runs through the magmatic system of Acatenango. The reason for this theory is to explain that some of the eruptions of Fuego carry magmatic signatures from Acatenango, but Acatenango never have the magmatic signature of the bulk of Fuegos eruptions”. What does that mean and where does the idea come from? I am aware of the hypothesis by some authors (e. g. Chesner and Rose, 1984) that magmas from both Fuego and Acatenango may have in common that they pond at the base of the crust, and then ascend through the crust to shallower independent reservoirs, but I think that’s different from what the blog post says. Maybe I’m not getting it right?

Overall I don’t see any evidence that Acatenango produces bigger eruptions than Fuego, and in that sense I don’t know what to make of the blog statement that “Historically Acatenango has not suffered from frequent eruptions. Instead the eruptions have tended towards being larger than the eruptions of its twin Fuego.” To my knowledge, the only Acatenango eruption for which there is any quantitative estimate of volume (eruption P-4 in Basset, 1996) has a min volume between 6.3 x 10^7 and 1.3 x 10^8 m^3, which would put it in the VEI 3 – 4 category range, similar to the 1971 and 1974 Fuego eruptions, and probably similar to those in 1932, 1880, 1717, 1581-82. The 370 BC pyroclastic flow mentioned in the blog entry, and which I assume would correspond to the sample AC.196 from Basset (1996) with a radiocarbon age of 2330 yBP, reached a distance of ~ 10 km from the Pico Mayor (Acatenango) crater, and although it would have been a large pyroclastic flow, the distance it reached is comparable to many of Fuegos pyroclastic flows. I think overall, both volcanoes can produce similar large eruptions, which is in itself very worrisome.

As you mention in the blog, the 370 BC pyroclastic flow would have cause a lot of damage if it would have happened in recent times, mainly because it’s on the other side of San Pedro Yepocapa (you can download the google earth .kmz file with the location of the sample as given by Basset, 1996, from here: http://www.geo.mtu.edu/~rpescoba/downloads/Pyroclastic_Flow_AC196_Basset_1996.kmz

Now the topic of evacuations is a very hairy one. It is very clear that a big eruption from Acatenango can easily destroy the towns around the volcano, but when such an eruption may happen, and therefore when to evacuate, is a very difficult question to answer. There have been at least two forma hazard assessments done for Fuego and Acatenango, the last one by Jim Vallance et al. (2001), which can be accessed here: http://vulcan.wr.usgs.gov/Volcanoes/Guatemala/Publications/OFR01-431/ Some larger (thousands of people) towns that could be within reach of eruptions like those happening in the past include San Pedro Yepocapa, Acatenango, San Antonio Nejapa, San Miguel Dueñas, and Alotenango, depending not only on the size and character of the eruption, but on the location of the vent (e. g. Yepocapa vs Pico Mayor). Calling for the evacuation of several tens of thousands of people, especially if the crisis extends for days or even weeks, and may not end in a catastrophic eruption, can be a very difficult decision. The people at CONRED (Guatemalan disaster reduction agency), the local authorities and most than anyone else the people at risk, would certainly face a hard choice. And one could ask hypothetical questions, like: should an evacuation be called for a crisis like the 1924 – 1927 eruption? What about the 1972 eruption? And if so, who should evacuate? Compared to what has happened at Fuego in recent years (e. g. September 13, 2012), these were really minor eruptions, but the potential for a catastrophic one is always there.

The record of eruptions at Fuego is also a controversial matter, which I hope I will be able to clarify at least a bit with part of my dissertation. The GVP lists 7 eruptions possibly having a VEI of 4, which are basically the same as those classified as “fuerte” by Meyer-Abich (1956), plus the 1974 eruption and excluding the 1953 eruption, which is given a VEI 3 in the GVP; but some of those older eruptions, like the 1737 eruptions may not have been that big or may not even have happened at all. It seems that at least the 1581-82, 1717, 1880, 1932, and 1974 eruptions were most likely in the VEI 3 to 4 category, and probably many more were at least in the VEI 3 category (e. g. the many eruptions happening between 1702 and 1717).

The blog entry states that “Two VEI-4 eruptions are documented, the last in 1974 when it had numerous pyroclastic flows killing residents in nearby villages.” Is this saying that the pyroclastic flows killed people? Or is it saying that the eruption overall (possibly due to other hazardous phenomena) caused those deaths? To my knowledge, there are no confirmed fatalities due to the 1974 eruption pyroclastic flows, although there were a few casualties from collapsing roofs due to airfall tephra accumulation. There have been also casualties due to the lahars.

I also have to take issue with your comment stating “What is lacking is good mitigation with pre-prepared evacuation maps from the valleys most affected by pyroclastic flows and lahars”. I don’t exactly know what you mean with “evacuation maps”, but I don’t think how maps would really solve the problem of preparedness and crisis management in this particular case. With all their limitations, CONRED, INSIVUMEH, the local authorities, and of course the people in the villages themselves have made a big effort over the last 10 – 15 years to improve their capacity to respond to volcanic crises. Whether or not such efforts are fruitful or not is difficult to evaluate, and may only be assessed with some degree of clarity in the aftermath of a (hopefully “successfully” managed, whatever that means) real volcanic crisis. My perception is that this will depend a lot on how the potentially destructive crisis unfolds from the volcanological point of view. As the situation is currently my gut feeling tells me that, if it develops very quickly without clear and scary precursors, producing large pyroclastic flows that reach the communities, it may end in tragedy. But if it develops more gradually and there are enough (clear and scary) premonitory signals, there are better chances that a large amount of people will evacuate. Heavy tephra fall in their communities may be in the end what could save people from the pyroclastic flows! Again, the September 13, 2012 eruption is something we should look at more closely to get a better sense of people’s potential response to a future crisis. In any case I see the current efforts, including the simulation exercise done at Fuego last week, as a good thing and a step in the right direction.

I think your comment “Also the will to evacuate and being evacuated is slightly low locally, something that can be understood if one think about that the people in the villages are really poor without the means to support themselves if they evacuate.” is a really important one, and I totally agree with this. The issue here can’t be isolated as a solely volcanic hazard driven problem, especially in the context of uncertainty.

Finally, your closing remark “If you think this was bad choice for cities” is a very interesting one, because it shows the perspective of someone who obviously is focused on the volcanic (and seismic?) hazard issue, but is not seeing the complexity and myriad of other things that may go into choosing the “best” place to settle a city. I agree with you (I have to, I’m a volcanologist/geo-hazardologist) that it would make sense to avoid geological hazards as much as possible, but I also recognize that avoiding climate related disease, having nearby fertile soil and water (especially in the context of the XVIII century), having some protection against potential military threats, etc, etc, and many more etc’s, certainly also played an important role. Putting the capital city in the northern lowlands of Peten, far away from most volcanic and seismic hazards may in the end not play out that well, if you don’t believe me just ask the Mayans…

RUDIGER ESCOBAR WOLF

P.S. All science and knowledge is driven by debate. It was an honour to have the insights and comments from someone who actively studies such an interesting volcano as Fuego. /CARL D.S.

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256 thoughts on “Comments to A Tale of Three Cities

  1. I would like to personally thank Rudiger for his comments, corrections and clarifications.
    Sadly things are never as clear as you wish them to be, and ontop of that I am limited fairly much to the english papers about the volcanism in Guatemala. Whenever I try to read the spanish papers I find that my spanish is not up to the task. And using Giggle Translate is not an option really. Something I discovered when I read a paper about Teide that all of the time referensed to “boiling cauldrons of leotards”.
    So it is with some trepidation I am sitting down to write part two, but thankfully Rudiger has promised to take a look at it before I publish it.

    Also, let us all ask Rudiger if he can write about Fuego for us. I for one would love to read that post 🙂

    • Carl, thanks for the opportunity to collaborate with this forum. I will be glad to give my input to part 2, and I would also be happy to contribute with a post on Fuego at some point. Saludos!

  2. nice post, and really glad the first post was written and that acted as a spur to Rudiger posting, Muchos gracias Rudiger & Carl 🙂

  3. Thank you Rudiger for the post 🙂

    In my ferreting around to find the lava composition last week, I came across references to the theory that Acatenango and Fuego magma systems may be interlinked. One was based on the fact that the two volcanoes are so close to each other. I can’t find the references again so can’t give more detail (the joy’s of internet search engines that think they know more about what you are searching for than you do!).

    I also came across the La Democracia and Escuintla debris-avalanche deposits which may have come from Acatenango and Fuego resp or their predecessors. Have you looked at these at all?

    Guatemala seems to be a very interesting place.

    • Given that Fuego and Acatenango are “twinned”, how do you work out which volcano produced which rock sample? Each is in range of eachother’s fallout / missiles.

      • It depends what kind of volcanic product it is and where it was located. In situ lava or pyroclastic flow samples are usually easy to related to their source volcano if they are “on the non-shared side” of the volcano, that would be the north side for Acatenango, and the South side for Fuego. As you may guess, this becomes somewhat ambiguous in ares to the east and west that could have been reached by both volcanoes. Detailed field relations, stratigraphy, age dating (for the last 500 years and assuming that all the deposits were produced by Fuego, although there is the intriguing possibility that some may have been produced by Acatenango), and as we have discussed before, geochemical and petrographic analysis can all help, but in some cases it may just be impossible to be certain about what eruptive center generated some deposits. The situation with lahar deposits is even more difficult, as they may not be generated by a specific eruption at all, and they frequently incorporate material from the different terrains over which they flow, to the point that question itself “what volcano produced this lahar”, may be meaningless. The case of air-fall tephra is also very difficult, because the location is less constrained that for flow phenomena. Thierry Basset, who did his PhD dissertation on Acatenango was able to use geochemical data and statistical analyses to differentiate between tephras from Acatenango, Fuego and Agua. And as we have commented in a separate post on this blog entry, similar methods were used to try to identify the source of the Escuintla and La Democracia debris avalanche deposits.

        • Thank you for this comment. It really put into center the problem of discerning what lava is from what volcano. Something that many in here are used to from Icelandic volcanoes.
          I enjoyed it a lot.

    • Karen, you read the same papers I did. Problem is that Google is no longer giving me the link to the paper when I search for it. Do not know why Google downgraded it into the deep mists… I should have saved the link.

    • There are several studies comparing and contrasting the Fuego and Acatenango magmas, as well as other “paired volcanoes” in northern Central America, for instance this paper (pay-walled but the abstract gives the main points): http://onlinelibrary.wiley.com/doi/10.1029/JB093iB05p04467/abstract
      It is usually assumed that the most primitive magmas for bot volcanoes are most likely very similar when generated in the mantle wedge, but become different as they follow different paths through the crust, to the point so, that Acatenango’s lavas may on average be more silicic. There is also a series of papers by Craig Chesner, discussing the magmatic systems and the commonalities and differences between Fuego, Acatenango and Agua. This paper ( http://www.sciencedirect.com/science/article/pii/0377027384900143 ) hypothesizes that the magmatic systems of Fuego and Acatenango are the same at the base of the crust, but then follow different paths, with Acatenango’s magmas having a longer residence time in the crust and therefore being more evolved. And the article about the La Democracia and Escuintla debris avalanches that you mention is probable also one of the articles by Craig Chesner and Sid Halsor ( http://specialpapers.gsapubs.org/content/412/105.abstract ), in which they try to identify the source of the debris avalanches by comparing the deposits to the potential volcano edifices that could have been the sources, i. e. Acatenango, Fuego and Agua. They compare both the geochemistry and petrography. The obvious implication is that, from the samples they work with, they consider the differences in petrography and geochemistry between volcanoes to be significant enough that it can be used to uniquely identify each of them as a potential source. As I said in my original comment, I suspect we would find more evolved rocks if we do a more in depth sampling at Fuego. For instance, some of the Fuego’s rocks that I’ve seen on my fieldwork at Fuego show a mingled (basaltic and probably dacitic) composition, but I haven’t done more analysis other than just looking at them in hand samples.

      • Birgit here takes wonderful pictures of volcano dust with SEM equipment at the Ars Electronica Center. If you have some samples to share, she collects them to add the collection. Contact her at spica308@gmail.com. I couldn’t find the link here to her pictures, but here is a link to a one of eyjafjallajokull ashes : http://archive.aec.at/pic/#34656

  4. On Reykjanes:

    How explosive is it? I was browsing the GVP website, and most eruptions have been explosive (and some really ashy and comparable to Surtsey, Hekla or Eyjafjallajokull). They are all between VEI0 and VEI4, most being VEI2 or VEI3. This is not a small eruption like El Hierro but something considerably larger like the recent Hekla eruptions.

    Where they occur? Some have occurred on land, just next to the airport (mostly small shield volcanoes) but most recent eruptions were located around the submarine region around the small island of Eldey.

    How often? Last confirmed eruption was in 1926. Some unconfirmed eruption are listed since then. Before these, there are probably an average of one or two eruptions per century (I refer to eruptions that make a ash column above the sea level). Therefore, Reykjanes is a volcano worth watching and we should expect an eruption likely earlier this century.

    Does Reykjanes herald an awakening of volcanoes in that region? Furthermore, if the period 900-1350 is to show us something, it seems that once Reykjanes starts to erupt more often, then the rest of the Reykjanes volcanoes (especially Krisuvik, the nearest to Reykjanes) can also have their own rifting eruptions more often, about a few eruptions per centuries.

    • The eruptions in 1783 and 1226 have been particularly ashy. The reports were of widespread ash fall around south Iceland. And a VEI3 or VEI4.

    • Hello Irpsit!
      There was a new lavabed found during a maritime campaign in 2010. That lavabed was not evident in a bathymetric scan done a few years earlier. So, it has erupted after 1926. Probably several times, but at such depths and scale that it was not noticed on the surface.
      Probably no small eruption would produce visible signs.
      The larger eruptions would though become very messy as they get closer to the surface with Surtsey style eruptions (explosive just before and just after breaching the surface, and then turning into rather effusive eruptions. It is after all the contact with the water that makes these purely unevolved basaltic eruptions go nasty.

      I would say that the volcanoes on Reykjaness Peninsula are less dormant now then before. We have had earthquake swarms in the Svartsengi Volcano, Krisuvik are showing a full battery of signs of awakening with magmatic emplacements, upliift, HT-episodes, drainage of the lake…
      Brennisteinsfjöll have had a bit of activity too, Hengill is thankfully most likely still dormant, and Hromundartindi have had at least one root filling in 98.
      So, yeah, they are active more or less. I would say that currently Krisuvik is the one most active, and as such closest to an eruption.

    • The eruptions next to Keflavik are the Svartsengi volcano which is not the same as the Reykjaness Ridge volcanic system (whatever now the GVP states). Even Reykjaness Ridge are different volcanoes… GVP is going by antiquated data on these volcanoes, so it is good if we could discern about them when we talk about them. Eldey volcanic system have had several smaller and a few larger lately.
      The current quakeswarm is though located around the Geirfugl volcanic system. That one has a tendency to crop up islands now and then. It was this system that produced the lavabed I referenced to earlier.

      • Svartsengi high temperature system is called part of Reykjanes system by eg. Thor Thordarsson and Ármann Höskuldsson, both Icelandic volcanologists, the former working at University of Edinbourgh. And the volcanoes on the Reykjanes ridge, are – some of them anyway – part of this system. But not all of them have been researched re. the petrology, so nobody knows exactly how far the system reaches out into the sea. Eldey is said to be part of the same system.

        • There is no evidence of them erupting the same lavas. On the contrary, they have separate feeders. Elder rocks are petrographically different.
          It is one of those instances where people just want to have an easy time.. 🙂

        • Inge: I even ask what sets apart of what defines the Reykjanes system and the Krisuvik system? Magma type?

          • Svartsengi has a slightly different petrographical record. And also the earthquake swarms point to different points of origin for the magma.

    • Just for the Newbys: Reykjanes here is (mostly) the southwesternmost volcanic system of Iceland, which is also called Reykjanes like the peninsula on which it is located. The systems center is at Gunnuhver, where you also have an important geothermal power station.

      The peninsula Reykjanes on the other hand, comprises also some other volcanic systems arranged in echelon from southwest to northeast: Krýsuvík, Brennisteinsfjöll incl. Bláfjöll, Hengill and Hrómundartindur.

      The eruptions mentioned were out to sea, the last on land were in the 14th century (perhaps – historical records, not in GVP).

      • Nope.
        Reykjaness is not a continuous volcanic system. It is, as all other places in Iceland, divided into a bunch of central volcanoes. The notion of there existing a Reykjaness volcanic system spanning all of the Reykjaness Ridge and Reykjaness Peninsula is just an old notion debunct a long time. Sadly GVP still propagates the notion.

        Reykjaness Ridge is divided into several volcanic centers, Eldey is one, Geirfugl another. There are though more of them.

        If we step up onto Reykjaness Peninsula we have foremost Svartsengi, Bláfjöll, Krisuvik, Brennisteinsfjöll as Central Volcanoes in their own right (with more existing of course).

        The Reykjaness Volcanic System is and was just a case of scientific laziness 🙂

        • Nobody says that all of Reykjanes Peninsula would be of a same volcanic system. Also GVP does not say that Reykjanes would as a volcanic system comprise the whole peninsula of the same name: just the “SW tip of the Reykjanes Peninsula” ( http://www.volcano.si.edu/world/volcano.cfm?vnum=1701-02= )

          BTW: Geirfugl would be a bird. The island was called Geirfuglasker (= Great Auk Skerry). Now submerged, since a submarine eruption in the 19th century there. http://en.wikipedia.org/wiki/Geirfuglasker

          Not all Icelandic volcanic systems have more than one central volcano. Most of them not (see eg. Snaefellsjökull, Öraefajökull). There are even some without one like the Grímsnes system near Irpsit.

          Re. Svartsengi the scientists seem not to be of the same opinion, if it is a different system or not (Thor Thordarsson, Ármann Höskuldsson, but also another Icelandic geologist, Ari Trausti Gudmundsson reason that yes). Eldey should is also part of this Reykjanes system, as Ari Trausti says that the systems reaches about 10-15 km out to sea.

          But Bláfjöll have I never seen called other than part of Brennisteinsfjöll system.

          • Hi Carl and Inge. The official information is for 4 main volcanic systems, but apparently only Hengill confirmed as being a central volcano: Reykjanes (submarine part and inland), Krisuvík, Brennisteinfjoll and Hengill.

            However the notion of what is a central volcano is highly subjective, maybe it should be dropped altogether. Nevertheless for the sake of simplicity and naming, it is easy to classify each region by a volcanic system name. But disagreements abound.

            One could argue that further out in the sea than Eldey there is another submarine rift region that could be another independent system of its own. From Eldey to the tip of Reykjanes, there seems to be one single volcanic system with many vents, both undersea (like Eldey was) and inland. Carl, if you happen to be on the tip of the peninsula, you will surely have this impression, by following the vents all in a single line from Eldey to Eldborg.

            Then, we find another fissure, Eldvorp, just touching both the edges of the fissure Eldborg-Eldey to the west, and Svartsengi to the east. Both Eldvorp and Svartsengi look like separate fissures, not in countinuity with the Eldey-Eldborg fissure region.

            There is no consensus with this as Inge pointed, and Carl is correct to suggest that these might be instances of where there was easy thinking. Therefore, what is called Reykjanes volcano can be 4 separate discountinuous fissure regions.

            Then, east from Eldey-Eldborg, Eldvorp and Svartsengi, we find Fragadalfjall, surely it seems like a separate system, but much older. Earthquake swarms there also seem to be independent from Krisuvik. However most, if not all, eruptions were Pleistocene.

            East from there we find the commonly accepted and highly active system of Krisuvik.

            Brennisteinsfjoll starts just at the edge of Krisuvik, but then further east we find another separate ridge: Bláfjoll, which could be also independent system. Again, the same question applies, what makes a separate system: being another fissure? Same lava? The feeder or a magmatic chamber?

            East from these, we find Hengill, a long fissure region, which just 3km east has another fissure: the Hrómundartindur. In 1998, an emplacement occurred there but did not affect anything at Hengill. Does this shows that it can be an independent system?

            If one consider Hrómundartindur an independent system, then Reykjanes must be 4 separate systems, with Fragadalsfjall and Bláfjollanother also an independent systems.

            But I said, the notion of what is a “volcanic system” is highly subjective. For instance, Hamarinn seems independent from Bárdarbunga but is within the same continuous fissure, as well as Torfajokull and even Tindfjallajokull! All within the same fissural alignment, with even eruptions occuring without regard for our notions of what is a system and what is the next one.

            Grimsnes is another good thing to study. Many monogenic separate cones, and a few Pleistocene eruptions around it. Some nearly at the edge of what GVP considers Hengill and Hveravellir or the Geysir system. So much confusion for science!

            Better to drop this attachment to the notion of what is a a volcanic system.

            Not even magma identity can be used to identity them. Volcanoes erupt often different magmas from one eruption to another. How does one draws a border?

            • I think I will have to write a rather long post on this one.
              Let it just suffice that the chemical composition is different from each of these volcanoes.

              Let me take one example. Brennisteinsfjölls magma is like a sore eye compared to the volcano to the east (Hengill) that erupts baseline basalt of the icelandic type. Same goes for the volcano to the west (Krisuvik) that has a different magma of the icelandic basaltic type. Krisuvik has a different composition in REM then Hengill, which sets it apart.
              What makes Brennisteinsfjöll is the same thing that gave it its name. Namely its very high sulphuric content.
              If we then move on from Krisuvik to Bláfjöll then we get a new setup of REM (lower amounts) untill we get out into the Reykjaness Ridge that have a very low REM amount but instead sulphur is getting back into action.

              REM = Rare Earth Metalls, mainly lantanides. But also Uranium/Thorium.
              Ie, the Reykjaness magmas are shallow decompression magmas of the MAR, but as we progress towards Hengill hotspot derived magmas get into play. Ie, not at all related.
              Brennisteinsfjöll has both the REM of the offset hotspot magmas, but at the same time shows sign of a sulphuric content origin.
              By the by, the REM count increase the closer you get towards the center of the current hotspot and is a distinct telltale sign of what magma came from where and is different between the volcanoes, but stay percentally the same regardless of the magmas grade of evolvement. So a highly evolved lava from Hekla has the same percentally grade of REMs as an unevolved. Ie, clearly stating it as Hekla lava.
              As we get to the two hotspot (ontop of) volcanoes on Iceland (Grimsvötn and Bardarbunga) we get rather silly REM counts as evident in Laki and Veidivötn magmas. Laki is high in some interesting Lantanides, and Veidivötn in other in the Lantanide Ur/Th series.

              As far as I have found there is only 1 anomalous dataset for the lavas/magmas in all of Iceland, and that is the Fimmvörduhals lava. That one had a very “peculiar” REM composition not found in any lava from the adjacent volcanoes.

              But, back to the volcanoes we where talking about. Look at REM as fingerprints, they are different from each volcano. And what both Irpsit and Inge forget is that a visible volcano is only the surface expression of something that starts many kilometers below the surface. The point of origin will give the lava on the surface, and if the point of origin is blatantly not the same you do not have the same volcano, regardless of what one would prefer to think about it.

              If anyone would like to state that the Reykjaness is the same volcano they will have to prove that the magmas have the same point of origin. Good luck with that.

            • Carl,

              When you refer to magmas from the same volcanic system having an identifiable REM ‘fingerprint’, well that’s spatial, but what about temporal? Over what timescale is that REM fingerprint consistent? Does magma from historical Krisuvik eruptions have the same REM signature as magma from pleistocene Krisuvik eruptions, say? How consistent is this over time?

              As for “As far as I have found there is only 1 anomalous dataset for the lavas/magmas in all of Iceland, and that is the Fimmvörduhals lava. That one had a very “peculiar” REM composition not found in any lava from the adjacent volcanoes.” – well that is intriguing I agree. Now there’s evidence of magma feeding into (or *evolving* into) Eyaf over quite some time, but it was the Fimmvörduhals intrusion that kicked the whole thing off. That was less than two years prior to Grimsvotn’s big show of 2011… with the big change in thorium abundance I’ve posted about before.

              What’s the REM fingerprint of Grimsvotn 2011 like, other than the thorium we know about? Could Fimmvörduhals be connected to the new upsurge from the hotspot, as Grimsvotn 2011 appears to be, with that explaining the peculiar REM? Or perhaps a bit of both… some very juvenile magma from the mantle mixing with some quite different basaltic magma lurking higher up, resulting in a mishmash of ‘young/old’ REM abundances at Fimmvörduhals?

              Stuff could have been ‘shooting off’ from the hotspot at deep and ductile levels with very little indication, ending up pretty much anywhere the hotspot influences…

            • Hello Michael!

              And that was a really good question… so I do not have an answer. At all.
              I do not even know if there is an answer out there to collect.
              I am as you might know heavily interested in mining stuff on a professional level. So, I garble up any info that might be interesting about where things might be interesting to mine. Especially I have snowed in on Iceland. No big secret there.
              So, I have collected almost every paper regarding content of the lavas on Iceland.
              Anyhoos, I have the one set of data or two for almost all the active volcanoes (and inactive) in Iceland. So, I can do spatial for Iceland. But I would need loads of more tests for each volcano on Iceland to do temporal.
              Only part of Iceland I can do a temporal analysiz is for Laki eruption. At Laki the lavas changed a lot between the three temporally and spatialy separated fissures that opened up. One can see them as 3 separate eruptions. The lava followed the path from a evolved magma mixed with fresh over to fresh only magma. The proportions between the various lantanides was the same throughout, but the overall amount increased drastically over time. But, the fingerprint is the same! 🙂
              What would between long intermissions is of course another thing.

              My guess is that as long as the deep feeder is basically the same that the changes will be small. But there will be slight changes depending ultimately on what comes up from the deep mantle via the hotspot, and that changes things a bit.

              Regarding Fimmvörduhals. It has a completely different fingerprint than either Eyja 1821 and 2010 had, it also has nothing to do with the Katla fingerprints. My guess is that it is magma that went sideways from the Gódabunga cryptodome. It might equally well be that Fimmvörduhals was some sort of new volcano. Anyhow, that magma probably kickstarted Eyjas eruption, and there should be mixed samples, at least from the beginning. But I have not seen any.

              Grmsvötn Thorium: Thorium comes up from deep down in the mantle, and it is actually possible to track overall changes in Thorium count with a cycle rate of roughly 270 years. In the end it is the final evidence that the Hotspot is entering a hightened period of activity. All volcanoes will soon show increases in Thorium, at least those closest to the hotspot.

              I might have a simplified version of looking at things, I just check the proportion of metalls, basemetalls and REMs, and then any lavas look very different to each other, even if both are almost pure olivines (as an example). It is a trick that kind of came naturaly to me since I am foremost a mining nerd at work. It also came since I am totaly and hopelessly unable to learn the geological names for stuff due to my name-memory problem.

            • Addendum to Michael!

              Last time Grimsvötn showed increased Th we had Lakí. Same goes for Veidivötn.
              Eldgja is not as clear on it since it is further from the hotspot. But, there is a small upwards “bump”.

          • Haha!
            You just made my day Karen!
            I wonder if Grindavik is the same as Svartsengi? Or if we have to tally up yet another volcano in Iceland.
            We should remember that Iceland has 150 dormant to active volcanoes (and counting).

            • Dunno – can’t find the paper with Svartsengi named in it. Vaguely recall it from a NtL sometime back.

            • I had it in my desktop that was annihilated when the water pipe burst in my former apartment.
              But Irpsit dug it out down in the comment-thread.

  5. Nice post, very informative.

    I’m posting my last comment from the last post here

    While looking up about the 1692 earthquake, I found a letter from Huygens (the guy from the Huygens principle) about this earthquake. Here is the google translation :

    “1692, Sept. 18. in Hofwijck in Voorburg at half past three in the afternoon, while I was reading a book, I suddenly felt an earthquake and not without fear. The house shook clear, and moved back and forth, so were beaten in the dining room hanging paintings at the gold leather that covered the walls. The stone floor on which I stood was slightly lifted and dropped again, and several times for about 10 or 12 seconds. The moat around the house, 60 feet wide, moved with some broad waves to the sides. Employees in the kitchen, under the dining room, had felt the same movement, and were anxiously rushed to me.
    There was no wind. I had some time on the assumption that the arsenal of Dunkirk was completely destroyed by gunpowder, as was expected every day that that city would be and would be. With rockets and artillery fired besieged by our army. But such a large distance could be barely as large print data to the air, and there was heard no sound or blow. Two days later we understood that there was nothing done to Dunkirk, and it was so really been an earthquake. And this also has to Amsterdam and Antwerp created all afraid. At an Amsterdam observer it seemed that, as it were waves from North to South (‘t NNW at’ t SSE) went forth, and all staggered. It is said that especially towers swung on an amazing way, and that naturally went ringing bells in some.
    My caretaker, seized by work in the garden, had not felt anything, I think because he was moving. Shortly after the movement had ceased, I went upstairs to inspect the barometer *). He was 12 degrees, while he had the previous day stood at 14 ° and 16 °. But the next day he fell further to 10 °, and it has abundant rained.
    Throughout Zealand, in Flanders in the forts of King William, Liège, Cologne, Paris, London and Scotland is the same movement occurred. In Hamburg appears to be not observed. In Liege he was violent, not without any damage. The time was there a quarter past two, thus earlier than here °).

    If the Earth through a kind of wave rises and collapses, she should be underground cave, or rest on water that then so moves. But from where is its movement? More likely is a cavity in which gather vapors, although they do not ignite as in the air, when it thunders.
    Could be something made out of the distance over which this sequence extends, about the depth of the holes and the vapors?”

    http://adcs.home.xs4all.nl/Huygens/19/meteores2-v.html

    The last paragraph I found actually very interesting. I don’t know when seismology came into existence but here he is already giving the principle behind calculating the hypocentre. And he also gives very clear the time and place where the earthquake was felt. I think this letter must have been a huge help for modern seismologists to study this earthquake.

    edit: The letter a bit ungiggled.

    • History of seismology: http://en.wikipedia.org/wiki/Seismology

      Also the theory of elastic wave propagation in solids was being developed in the 1800’s (Cauchy, Poisson, Stokes, Rayleigh et al. In the 1900, P and S waves were detected on seismograms. (From “Introduction to Seismology”, Peter M Shearer, Cambridge University Press, 2011 (reprint).

    • Thanks all for the informative comments.

      Interesting in the comment by Huygens above, about the gardener feeling nothing. It reminded me of my own experience in Cambridgeshire on the edge of the fens, as I may have mentioned previously – apologies if you have heard this before: I was lying on the grass in the garden enjoying the early summer warmth and heard bump bump from the main road as a lorry went over 2 ‘ripples’ travelling down from King’s Lynn where the epicentre was. I then felt them move smoothly under me as they went south. Within the city of Cambridge the tall buildings rattled, things fell off shelves, tiles crashed down into the streets, and some brick buildings were cracked.

      The fens are soft deep loam soil. I think Cambridge itself may be more clay.

  6. Thanks Rudiger for an excellent comment – so glad it was rescued. I’m sure it would be enormously appreciated if you could do something on Fuego for us, and of course I’m really looking forward to the next ‘Three Cities’ instalment. A while ago I harboured some thoughts about doing something on Guatemala, but glad I didn’t as first Carl and now you have done far better than I could have!

    Anyway, that arch must be the most photographed in Guatemala. As I mentioned before, I spent my honeymoon there so I had to go dig out some photos. Here’s what the scene looked like in late 1993 – in a wonderful, heady, mystical time long ago before children!! 🙂

    • Yepp, I will never forget that arch myself… I guess I will be hit over it for the next couple of years. 🙂

    • Thanks for sharing your picture! I agree, the arch is certainly one of the most famous street views of Antigua. I’m glad you choose Antigua as your honeymoon destination, it is a truly relaxing and enjoyable place.

      • Well, Antigua was relaxing, certainly. Tikal and Chichi were a bit more lively, while Atitlan counted as quite an adventure (no-one really knew at that time whether we were ‘safe’ going there or not – well, I’m still here so we probably were!)
        Great times and a truly gorgeous place (sigh….)

  7. Somewhat off topic, probably more related to earthquakes than volcanoes.
    You have probably heard of the garment factory collapse in Bangladesh where over 1000 people died, and you’ve also probably heard that a lady was pulled living from the rubble 17 days after the collapse (which was about 10 days after the searchers really expected to be finding anyone alive). I saw somewhere it was mentioned that she’d coincidentally been near food and water, and that she was trapped in a large void but otherwise ok.

    Then I thought about the usual advice for what to do in an earthquake – drop, hold, cover etc
    It seems to me that no one really suggests that if you have a slight choice about where to do that it ought to be near food, water and any other survival type gear you might have (just in case you do end up trapped). It seems obvious to me now that if I were in a building collapse and trapped I’d be ever so slightly more likely to survive if I happened to be near a sleeping bag, first aid kit, food and plenty of water, but I hadn’t thought about it -perhaps in earthquake prone regions you should have all that in your desk drawers so that when you hide under your desk you have resources available should the unfortunate events occur? Just a thought anyway.

    • Seems to be a very good idea. 🙂

      One never knows, where we are in the exact moment, but chances are that it would be at the work place.

      I was outside hiking not far from Reykjavík, when the Iceland 2008 one struck. It was strange, the whole landscape started dancing around me. Luckily no lose rocks in the vicinity!

    • For more info on the relatively unkown Xela Caldera, see here – http://pubs.er.usgs.gov/publication/70018325

      It appears that the volcanoes that have sprouted in that general area are the typical Somma stratovolcanoes that commonly form around the rims of previously collapsed calderas. I’m not sure if Santa Maria would be part of this, but Almolanga definitely seems to be a sprouting somma that’s forming from the same magma source that the Xela Caldera derived from.

  8. Many thanks to Dr. Wolf!
    I believe that Carl and the dragons, as well as everyone else here that are boldly striving to keep a healthy and truthful discussion in VC certainly feel much honored to have an expert’s appraisal such as yours on the material produced by our ruminations.
    I’m rank super-amateur among amateurs, but most happy to welcome your further installments.
    🙂

    • Great image! Lots of people living very close to volcanoes. Among the most worrisome is Quetzaltenango (my hometown, also known as Xela), with a population of a several hundreds of thousand of people, located virtually “on” part of the Almolonga volcanic complex, which includes a small caldera and many domes. The last eruption happened in 1818, when a blocky lava flow erupted from Cerro Quemado (one of the dome complexes), an threatened the town of Almolonga. You ca see the lava flow here:
      https://maps.google.com/?ll=14.801978,-91.508303&spn=0.023318,0.042272&t=h&z=15
      and Xela to the north and west (if you zoom out). And speaking about Xela, the whole valley (30 – 40 km accross) is also a much larger caldera, much older (maybe miocene?) and very unlikely to erupt in a near future, but a caldera nevertheless. John Ewert briefly discusses the Xela case (as well as the San salvador case) in an article that I posted in this forum before, but I’ll re-post it here because it’s relevant to this discussion: http://www.geotimes.org/apr04/feature_VPI.html

      • I posted a reply to this comment, but posted it in response to the wrong person – sorry for the double post!

        For more info on the relatively unkown Xela Caldera, see here – http://pubs.er.usgs.gov/publication/70018325

        It appears that the volcanoes that have sprouted in that general area are the typical Somma stratovolcanoes that commonly form around the rims of previously collapsed calderas. I’m not sure if Santa Maria would be part of this, but Almolanga definitely seems to be a sprouting somma that’s forming from the same magma source that the Xela Caldera derived from.

        • ROUGH guess. The abstract points to it being 30 km “wide” and taking up Quezaltenango basin. If I am on the correct one, and that is a caldera, it’s 30 km long and ranges from 10 to 15 km wide.

          A 30km by 10 km “caldera” would work out to 235 km³, 30km by 15km → 313 km³ DRE of ejecta over the lifetime of it’s formation, based on the eruptive volume relationships of of other published calderas.

          Whether it was a single event or a collection of eruptions over several thousand of years is up for grabs.

          That is if I’m looking at the correct “caldera” and it turns out to actually be a caldera.

          And an “oops”: From the abstract → “The caldera outline is broadly circular”, if so 30 km by 30km is about 514 km³.

          If you could point me at a plan view diagram, I can make a better guess.

          This reminded me of Heart Mountain:
          “Within its northern part, Xela caldera contains a toreva block, about 500 m high and 2 km long, that may be incompletely foundered pre-caldera bedrock.”

          Heart Mountain (Wyoming) is what remains of a monstrous landslide.

          “Between 50 and 48 million years ago a giant sheet of rock about 500 square miles (1,300 square kilometers) in area detached from the plateau south of the Beartooths and slid tens of kilometers to the southeast and south into the Bighorn and Absaroka Basins.”

      • Wow! You lived very close to that lava flow area! Is this why you decided to study volcanoes? Fascinating but potentially dangerous to live so close.

  9. This is slightly OT from the primary post (Awesome having Rudigar here!), but I would like to request the “researchers” and generally curious population of VC to look into the Lake Managua and Lake Nicaragua region of Central America (which is further south in the Central American volcanic arc than Guatemala).

    Why?

    There is some serious downfaulting going on there. Lake Nicaragua is a very large tectonic depression formed as a graben in the middle of a subduction zone. Rifting and downfaulting (not sure if that’s the proper term) in the middle of a subduction zone is the basic recipe for creating a massive rhyolitic caldera structure.

    For reference, this is the same general principle that forms the Taupo Volcanic Zone in New Zealand, the Caldera zones in Southern japan which includes Aira, Ata, Kikai, and Aso, the Taal and Lago Azul calderas in the Phillipines, and even Toba in Indonesia.

    • Good Lord I hope not. Taupo Volcanic Zone is made up of numerous caldera systems. Taupo itself overlaps the Whackamaru caldera and could conceivably be a daughter system of it.

      GL Edit: Whackamaru would have given Yellowstone a run for the money at 30 x 40 km. Remember, Whackamaru showed significant zonation while Taupo showed none. Thats a pretty weird thing. It points to either a rapid onset and eruption of Taupo, or a lot of mixing going on.

      • I don’t believe that there is any major volcanism associated with the area, but from my very limited knowledge, it seems to have all the same elements that are associated with other rhyolitic caldera provinces scattered around the world.

        Then again, I wouldn’t expect that area to be highly studied in terms of ancient volcanism, so who knows. There IS a pyroclastic shield volcano that sits between managua and Lake Nicaragua (Masaya), although it’s relatively small when compared to other rhyolitic caldera complexes. Also, if on the unlikely chance that there were a volcano or caldera structure buried beneath lake Nicaragua (Concepcion and Maderas as somma volcanoes perhaps?), it wouldn’t be too surprising if it wasn’t discovered. Nicaragua isn’t a super rich country with loads of money to devote to volcano research.

        For whatever it’s worth, lake Nicaragua IS tectonic in origin, but that type of tectonic expression of downfaulting and rifting in a volcanic arc is what can lead to large rhyolitic magma chambers. I would re-read Bruce’s writeup on the Taupo Volcanic zone, since on the very surface, it looks like a similar process of rifting and crustal thinning is going on in that area.

    • Wiki describes Lake Nicaragua as tectonic in origin. http://en.wikipedia.org/wiki/Lake_Nicaragua

      It does have volcanic islands in it:

      Concepción and Maderas (both stratovolcanoes) on Ometepe
      Zapatera, a shield volcano, on Isla Zapatera

      Concepción is active and overlies lake sediment and an old caldera: http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-12%3D

      Maderas is Holocene but not considered active. http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-13-

      Zapatera is also Holocene. http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-111

    • No caldera structures…? There seems to be quite a lot of fun large caldera systems there. But they seem to come in the form of pyroclastical ultra massice shields… Impressive ones really.
      The entire western shore of Lake Nicaragua is riddled with active volcanoes.
      You have the Chiltepe pyroclastic shield, Apoyeque, Xilóa Maar, Talpetalt Lava Dome, Masaya (plinian), Momotombo, Monté Galán (caldera) Momotombito (island in Lake Managua) Nejapa-Miraflores, Ticoma, Asososca Maar at Lake Managua.

      Moving on towards Lake Nicaragua we find Masaya (caldera), Las Sierras (pyroclastic shield), Nindiri, Santiago, and on and on…

      It is a very interesting place…

  10. I did not understand the comment on the blog stating that “some researchers have extemporized that the magmatic system of Fuego runs through the magmatic system of Acatenango.

    This is the sort of thing that gets lodged in the back of my mind, that later becomes a nagging “where did I hear that before?” when I run across it again in the future. I then wind up on a web spelunking expedition to see where that notion comes from.

    If you have evidence that the notion is not extemporized and is in fact based on real data that you have already come across, personally, I would dismiss it. But that’s just me. It’s roughly the mindset with which I approach some “loon” theorists that wander in here from time to time. Quite some time ago, I took a gobsmackedly large number of earthquakes from the USGS listing and located the ephemeris data for the Sun, Earth, and Moon for the times of those quakes. I found that there was no pattern that I could dig out, and at best, that there may be a slight correlation with the moons positions, but there was not enough of a signal there that you could point at as being proof of anything. I had a lot of fun with that one. It comes in handy from time to time when someone predicts a monster quake based on astronomical positions. I would throw the plot at them and say “Show Me.” A while back, Berkley USC came out with a news release that shows some correlation with San Andreas quakes, but it too was ephemeral. I think that is what I found in my rummaging around in the data.

    Caveat: Not a statistician, but I did feed my dog a cookie a while ago.

  11. OT: Sideshow.

    Lets say, for sake of argument, that I have an underground chamber, say 30,000 liters in volume from a tank that I buried a few years ago. I have a pipe that I can use to fill this tank that extends to the surface. What does it mean if I start filling the tank and have put 50,000 liters of material down the pipe into my 30,000 liter tank?

    Think there might be a problem?

    Yup. Hello Bayou Corne.

    Parish officials say the volume of the brine-filled sinkhole is much smaller than the amount of displaced earth now in the cavern, prompting worries about other unknown subterranean voids or gaps left in the area by the shifted sediments that could lead to further disturbance at the surface.

    http://theadvocate.com/home/4209995-125/officials-sinkhole-math-doesnt-work

    • So… why am I posting “doom” related sinkhole stuff? Because the mechanics of what is going on down there are essentially the same as a collapse caldera, but without the explosive volcanism.

      It’s just plain interesting. An evacuated chamber with the roof falling into it.

      And for those who are into helicorders… there are a few down there so you can see the seismic activity as this thing progresses.

      http://folkworm.ceri.memphis.edu/heli_temp/

      BTW… if you see harmonic tremor, something really really odd and most likely bad has happened. If I remember, the geothermal gradient in the area is about 10 to 15°C/km. There really should be no magma in the equation. The deepest part of the affected chamber should be about 3500 feet deep. Of course that doesn’t mean that you can’t have some sort of energetic fluid flow. So, if you see it, “oops”.

    • Lurking, if you have a 30 000 liter tank in your back yard I hope that it has something to do with ‘shine production…

      • BATF would be on me like stink on fecal matter.

        Many years ago, my uncle used to have a gas station. I have seen what happens when a mostly empty petrol tank finds itself in highly saturated soil after a heavy rain. Buoyancy can take over and they pop to the surface like corks.

        I imagine that this is one reason that burials are usually six feet deep. Imagine a graveyard full of coffins doing the same thing.

        • Even I would for a few seconds believe in zombies on that freightful night….
          I am not easily scared of things like that, but… I think it would be another instance of brown pants. Would be my fourth…

  12. I have only just managed some time to spend in VC. Firstly, my sincere thanks to Dr Wolf for taking so much time to help us widen our knowledge and see another perspective. I, like Renato says am a very amateur amateur and I admit frequently to getting bogged down by mathematics and physics… but I plough on !
    I feel very honoured to be able to read information from someone who knows these volcanoes well. (Or as well as anyone can “know” a volcano.) It is excellent to read that great efforts are being made to provide knowledge and safety procedures to the people in the shadow of these volcanoes.
    Secondly thank you to Carl for making sure Dr Wolf’s comments were presented to us.
    I shall have to read the post again ,preferably tomorrow morning with my coffee and some time to digest the information.
    If the Bar is still open will someone pass Dr Wolf a drink of his choice from me 🙂

    • Indeed, KarenZ – that was going to be my next question – what is going on here???

      UTC Latitude degrees Longitude degrees Depth km Mag[+]

      Region name
      [+]

      2013-05-11 10:25:36.0 26.72 N 57.71 E 20 4.3 SOUTHERN IRAN
      2013-05-11 10:03:05.0 26.68 N 57.78 E 20 4.6 SOUTHERN IRAN
      2013-05-11 08:42:40.0 26.66 N 57.84 E 30 5.0 SOUTHERN IRAN
      2013-05-11 08:38:24.6 26.49 N 57.70 E 20 4.0 SOUTHERN IRAN
      2013-05-11 07:58:38.3 26.44 N 57.78 E 15 4.2 SOUTHERN IRAN
      2013-05-11 05:59:40.0 26.78 N 57.99 E 20 4.3 SOUTHERN IRAN
      2013-05-11 05:45:32.0 26.53 N 57.63 E 20 4.0 SOUTHERN IRAN
      2013-05-11 05:34:17.0 26.58 N 57.78 E 30 4.4 SOUTHERN IRAN
      2013-05-11 05:21:28.7 26.68 N 57.67 E 21 3.9 SOUTHERN IRAN
      2013-05-11 04:53:35.0 26.61 N 57.79 E 17 3.8 SOUTHERN IRAN
      2013-05-11 04:51:02.7 26.42 N 57.51 E 28 3.8 SOUTHERN IRAN
      2013-05-11 04:09:30.0 26.53 N 57.89 E 20 4.7 SOUTHERN IRAN
      2013-05-11 03:58:17.0 26.83 N 57.60 E 20 4.4 SOUTHERN IRAN
      2013-05-11 03:41:31.0 26.69 N 57.99 E 20 5.0 SOUTHERN IRAN
      2013-05-11 03:17:23.0 26.53 N 57.58 E 20 4.7 SOUTHERN IRAN
      2013-05-11 03:09:54.0 26.78 N 57.91 E 20 5.4 SOUTHERN IRAN
      2013-05-11 03:03:29.0 26.64 N 57.80 E 20 4.8 SOUTHERN IRAN
      2013-05-11 02:50:02.0 26.59 N 57.93 E 20 4.6 SOUTHERN IRAN
      2013-05-11 02:45:43.3 26.42 N 57.76 E 16 4.1 SOUTHERN IRAN
      2013-05-11 02:32:44.0 26.65 N 57.87 E 20 4.5 SOUTHERN IRAN
      2013-05-11 02:29:45.0 26.76 N 57.96 E 20 4.6 SOUTHERN IRAN
      2013-05-11 02:08:14.0 26.79 N 57.85 E 30 6.2 SOUTHERN IRAN

      It seems to be a massive faulting of some sort – the deepest recent quake was 49km

      GL Edit: Minor formatting, removed about 11 additional events that wouldn’t line up correctly.

  13. Carl, Inge, look at this article
    http://beta.isor.is/efni/jardfraedikort-af-sudvesturlandi-reykjanesskagi-yfirlit-um-jardfraedi

    They speak of 6 volcanic systems in the Reykjanes peninsula: 1) Reykjanes, 2) Eldvorp-Svartsengi, 3) Fagradalsfjall, 4) Krisuvik, 5) Brennisteinsfjoll/Bláfjoll, 6) Hengill

    In another map I saw today, the Reykjanes volcano only included Eldey and Eldborg, further out in the sea, where the swarm occurred yesterday, it is supposedly a separate volcanic system/ fissure swarm.

    • They also add a graph showing the cyclical nature of eruptive activity in the Reykjanes peninsula. If the average works, then between now and 300 years in the future, we will have most volcanoes in the peninsula coming to life again and erupting often within short periods of time between each other. This period of activity should last for a few centuries.

      • If that statistical work equates to reallity we should be seeing the volcanoes awakening. Oh wait, we have awakenings in Krisuvik, Svartsengi and Hromundartindi.

    • Yepp, that is the one I have seen before. And another one that separated the Bláfjöll/Brennisteinsfjöll from each other due to sulphuric inconsistencies.

      Yepp, Geirfugl is supposedly the first of the non icelandic MAR volcanoes.
      Anyhoos, always look at the bottom of the volcano, never at the top 🙂 (if you want to know if it is the same or not)

      Thanks Irpsit for digging out the reference I misplaced.

        • I’ve only had two semesters of Spanish. I can’t speak it. Nothing to be shocked about. I can speak a bit of PhP and Pearl though (with a reference guide)… Though I think my Spanish is about as good as my C++.

          • About as good as my spanish then.
            I lived for half a year in Spain as a youngster. I can order food and read spanish pretty well. And of course notice that when Giggle Translate says “Boiling cauldron of leotards” something is wrong somewhere…

            • Oh Carl, that made me laugh! Even I know that something is wrong when one comes across a boiling cauldron of leotards! And my Spanish is as good as my Swedish which consists of Jag är hungrig, Jag är torstig, and Hjälp!!!!

            • That is all you need in swedish really…
              and of course… “Jag vill äta surströmming!”

            • YIKES!!! I will pass on that one I am afraid. I think if I tried I would erupt as violently as Hekla! Oh an sad to say I had to google that although I DID know the reputation of surströmming! My father was Czech and some of the things he would eat turned my stomach badly enough.

            • I must admit that I find it quite tasty, but then I am born and bred on the stuff. 🙂

            • What I really want to know though is if surströmming is smellier than durians whose smell has been described as “the smell of overripe cheese, rotting fish, unwashed socks, and a city dump on a hot summer’s day ” ???????

            • I have never had a close encounter with a durian fruit, just heard that it smells awfull.
              But, as with the surströmming the durian is supposed to not taste as it smells.

            • More surströmming for me come surströmming season.
              Late august is when there is the surströmming premiere, I am looking forward to it. And as any real afficionado that is the time when you start eating last years batch since it is more matured and balanced in the flavour.

            • Fair enough 🙂 I like that my gravatar shows my thoughts on fermented herring, you’re welcome to it Carl, but don’t get too ill eating my share 🙂

            • Actually it is really easy on the stomach if you can stomach the smell 🙂
              Since I have been eating surströmming since I was a small kid I start salivating and get really hungry if I just feel a wiff of the aroma from a newly opened can.

  14. Carl, The other day someone inquired how to get off the auto email notification for replys thing.. Seems they selected it and got flooded with update stuff. Any ideas?

    • Sheep. Right? Does this poster means you are bored, and need a cheering up? Awful quiet here today. Much like Sunday likely. *not expert*

      • Awfully bored…
        I waited for seven hours for a comment… And then I finally had a piece of spam to gobble up.

        • Oh, I see. Nicht gut. …but no news are good news. Likely does not work with comments here. Calm before the storm? U got mail ..

        • Well, I spent the evening pondering the idea of how more stuff can fall into a hole, than the hole is big. (that 30,000 liter thing I mentioned earlier) Then I dozed off to sleep.

          For Mothers Day, the only thing my wife had wanted was to go out for breakfast with her two daughters. Unfortunately, one of their Mother-in-Law’s wanted to horn in an dominated the occasion as is typical of her self centered personality. (This is the sort of lady that causes me to avoid some “family” get-to-gethers because I have a tendency to advise people of just how F’d in the head they are when they show their ass… in a manner and vocabulary typical of a veteran sailor. Me opting out has led to less consternation between the two side of the family.) Anyway, my wife opted out of the breakfast thing. When I got up, she was reading the paper on the couch. A bit forlorn, based on here deameanor. (yeah, husbands can read body language despite what you women have to say)

          So, I made ham and cheese omelets. (yeah, I can sling a mean frying pan also) That seemed to cheer her up a bit.

          I try to never wish ill upon a person, but I do wish karma upon them. Everyone gets what they deserve… eventually. If you are lucky, you get it while you are still alive and don’t have to deal with it in the afterlife… that side of the equation is permanent. As far as I know, there are no variables to balance out when you reach that point. As the ancient Egyptians looked at it, if your soul is heavier than a feather, you’re done. Might as well scrape your name off the monuments, no one want to remember your name.

        • Just spent the evening reading “Surviving Galeras”.

          Schteve42 asked what the precursor was. It was a tornillo but unfortunately the party of volcanologists had already set out and the significance of tornillos was not understood at the time so they were not alerted to the one that preceded the eruption.

          The book also refers to mariposas, another type of volcanic earthquake (high frequency events which occurred from fractures on the surface of the lava dome preceding the 1992 eruption (but not the 1993 eruption)). Any one have an image from a seismogram of one of these?

          • mariposa means butterfly so I guess that the shape would have some resemblance to a butterfly. dunno if that helps.

  15. I wouldn’t be surprised if someone hasn’t already linked to this article here – but if not then it seems to have a fair bit of interesting speculation to go with the Hekla correlation:

    http://chiefio.wordpress.com/2013/05/06/hekla-ing-egypt/

    And some praise indeed for Volcanocafe’s informative posts.

    By the way I haven’t been able to access the Hekla web-cam for a few days, or maybe I just time it for the same time as everybody else….

  16. Brought here because it’s caldera like… though not a caldera.

    A couple of new subsistence formations in the middle of Nowhere, in Alaska.

    http://www.alaskapublic.org/2012/12/07/explosion-near-eagle-leads-to-mysterious-geologic-slump/

    “It’s been really interesting to watch because it’s still steaming and still burning but if it is indeed oil shale as USGS suspects, oil shale and sulfur, it could be as deep as a thousand feet which means it could have been burning for some time from a lightning strike years ago and it’s been burning underground and finally burned enough to cause a slump or a crater like depression in the earth so until we actually get boots on the ground and we don’t know when that’s going to happen, we’re not going to know,” Sanders said.

    Eagle is about midway across Alaska (north-south) near the border with Canada.


    And a dose of debauchery, Chicago style.

    • I guess genetics really should be thought in schools regardless of other issues…

      “In February, Andrew Mendoza pleaded guilty to public lewdness and criminal trespassing for trying to make a baby with his neighbor’s horse. “I was thinking it would have a horseman baby,” he stated in a court document.”

      I guess words are not needed…

    • And of course the burning oil shale caldera was at Sheep Creek, how fitting.

      (and below the Sheep are flying in a blizzard)

      Poor sheeps, is it not one thing, it is another.

  17. Then and now…

    In either 1729 or 1730 a snowstorm visited Scotland, in which about twenty thousand sheep and many shepherds were lost – “by a single day’s snow.”

    A Chronological Listing of Early Weather Events 6th ed James A. Marusek

    Snow storm: Sheep death toll reaches 20,000
    More than 20,000 sheep were lost in the recent snow blizzard, and it may be next month before all the dead animals are found and counted.

    http://www.bbc.co.uk/news/uk-northern-ireland-22170773

    The Little Ice Age, according to NASA, “defines the term as a cold period between AD 1550 and AD 1850”

    • And the $64 question….

      The last I looked, the largest stratospheric popping eruption was Grimsvotn. The largest release of SO2 came about a week after the eruption, which by that time, was over. Did Puyehe, and other systems put enough SO2 up to be of any consequence over the long haul?

      Generally, the LIA is attributed in part, to volcanic activity.

      WE just had a rhyming sheep death in Ireland to what happened in Scotland 283 years ago.

      (note, History doesn’t necessarily repeat, but it does rhyme quite often)

      When a freshwater icefloe makes landfall… it can eat houses, or at least try:

      http://www.winnipegfreepress.com/local/Ice-destroys-several-homes-along-Da-207043001.html

      • Snowstorms, even really unusually large ones can happen due to other factors than volcanoes.
        A few years ago we had a honking big one dumping on one of our cities. We normally never notice a large snowstorm more than that some smaller roads might take an hour to open. Reason for this being that we keep wast amount of snow clearance equipment at hand. And I mean giant fleets of equipment.
        This snowstorm took out an entire city for a week and shut of the northern railroad system and the lifeline road to northern Sweden. Even though pretty much all of Swedens available heavy equipment was thrown at it and the military, it was so bad it took a week to clear away.
        It happened in a year without even a VEI-4.
        All it takes for a huge snowstorm to form is for a large mass of moist warm air meeting some really cold air. Ka-bam!
        My guess is that the Arctic high made one of its rather unamusing wanderings slightly west of the normal trajectory and met the Icelandic low… That combination produces snowstorms that are hundreds of times more energetic then a hurricane. The phenomenon is called an arctic bomb. About as fun as it sounds. One minute you have -40C, next minute the temperature goes up to about -5C and a sheep hits you in the face (or about anything that can fly). The air pressure drops so fast that your ears pop and your sinuses hurt like hell. It is one of those times you do not wish to be outside of a warm house, you normally die if you are not.

        • I never felt that effect! Surely polar storms can be violent. But I think in terms of wind and pressure, they are just the equivalent of a category 1 or 2. Every other week in Icelandic winter, storms with sustained winds of 120km and sometimes more (like 150 or 160km/h), mostly at the highlands and open sea, and gusts up to 200km/h.

          Yes, pressure can drop quickly, but at most down to 920mb. And it takes several hours. That is like to hike from sea level to roughly 1000m altitude within a few hours. Its not that much!

          Yes it creates a difference of pressure enough to make its presence felt if it occurred within mins. But you cant feel it when it changes over hours. Unless you have bones sensitive to those pressure changes.

          • Remember that the storms you face are normally just regular snowstorms created by the Icelandic low pressure.
            The arctic bomb requires that a low pressure with high moisture ratio runs smack into a the arctic high pressure (with ultra dry air) at high speed, and ad the circumpolar jet and you have a party that is brutal. It is uncommon, but horrible. I’ve seen one up and close, I will avoid it again.
            It has more energy then a hurricane, but it covers a much larger area, so the net wind is not as bad. The crucial thing is that the snow dumps down very fast at the intersection between the high and the low. The wind area is much bigger then the snowfront.

  18. Hi Carl!

    I loved your reply to both the Reykjanes question, and the Fimmvorduhals lava thing.

    On Fimmvorduhals, well it is not a new volcano. Around the spot of the last eruption, there are some old volcanic cones, and they look like Holocene, when I was there in 2010. I think that area erupts quite often geologically speaking. And it is just nearly outside of both glaciers, Eyjafjallajokull and Myrdalsjokull, at the point they meet each other. Do you think Fimmvorduhals could have had a direct deep feeder, of the same magma as a hotspot pulse that also originated Grimsvotn 2011 eruption?

    Regarding Reykjanes, yes I realize your point that volcanoes are the surface expression of something more deep, related to their lavas. You said that Krisuvik has a slightly higher REM than Brennisteinsfjoll. Was my understanding correct? Because Krisuvik is further away from the hotspot than Brennisteinsfjoll.

    What about Bláfjoll and Brennisteinsfjoll? Are these two ridges having the same lava type or are they different systems?

    On Reykjanes “volcano”, I also consider it as several volcanoes. I think it makes sense to name one as Reykjanes (the one forming Eldey and probably also Eldborg at the tip of the peninsula). Svartsengi, like you suggested, could be a different one. Do you know anything about the Eldvorp fissure? It has been suggested as part of Svartsengi and that fissure erupted quite recently in the Holocene.

    Then, there is Fagradalsfjall? Do you know anything about it?

    • First, my apologies for sticking my 2¢ in. Ignore if you wish.

      Krisuvik is directly over the landfalling part of the MAR. In My Opinion, Krisuvik is a transitional system much like the rest of the other Reykjanes volcanic areas. Once you reach Hengill, the dynamics become more akin to stratovolcanoes… with Hekla being pretty much the last holdout, part monstrous overgrown crater row, part stratovolcano.

      I imagine that the REE seen at Krisuvik is not that closely related to the hotspot… but I could be very wrong. I also used to think that gnomes didn’t exist until one was spotted trying to cross a road in South America. Now the big question is why did the gnome want to cross the road?

      • I agree, the REM should not be that closely related to the Hotspot, I am more thinking about remelt material of crust that is produced by old eruptions when the hotspot affected. But the count is way lower then over at the hotspot.

        Oh my how much fun the “Gnome” must have.

    • Actually, I would love samples of those cones around Fimmvörduhals. Would be grand if it was a separate volcano after all. And getting the same type of fingerprint from more cones would kind of prove that (or prove that there is an odd fissure from Gódabunga and that it is older. Or even proving the illusive connection between Eyja and Katla. Interesting anyhow.

      No, I would doubt that Grimsvötn share the same deep feeder, unless one counts all of iceland as the same volcano due to almost all of Iceland sharing the same hotspot and mantleplume. The Fimmvörduhals quakestack went a completely different way (thanks Lurking!)

      I think Brennisteinsfjöll is a bit of a conundrum. My guess is that it is partially melting a very sulphuric old deposit, or that some other process is in action. Yes, it is slightly lower. Why I do not dare even guess.

      I have not a good set of data on Bláfjölls REMs so it is hard to say anything really.

      About Eldvorp I only know that it has erupted recently, but locationwhise I guess that it is part of Svartsengi volcano.

      Fagradalsfjell I know almost nothing about.

      • I might go to Fimmvorduhals this summer, in soon. If I go I will bring samples. Its a long hike to get there, about 5 hours up and 3 hours down.

        The Fimmvorduhals line of cones seems to extend towards the Godabunga cryptodome, which is 8km east. And also extending WSW towards that spot south of Eyjafjallajokull, where large GPS movement was detected prior to the eruptions. That is also 8km away.

        However the new fissures/cones in Fimmvorduhals occurred a bit north from the old ones, about 1km away. And if one aligns that new fissure in a westwards motion, one ends up at the crater of Eyjafjallajokull, also 8km west.

        I cannot make my mind of anything. I just have in mind the Geolurking graph of quakes, showing where magma came.

        What makes me question is why the GPS movement was larger in the south region of Eyjafjallajokull some weeks before, while the quakes at Fimmvorduhals seem to show another feeder.

    • Carl, this is also a reply to one of your former comments. On the 270 year thorium icelandic hotspot cycle, do you have a paper reference for that?

      I can roughly find a pattern: 934 eruption of Eldgjá, (and 2 x 271 years later) 1477 eruption of Veidivotn (and 306 years later) 1783 eruption of Laki (and 270 years later) gives circa year 2053
      Can’t find an episode between Eldgjá and Veidivotn, supposedly around year 1204.

      But I can find another probably cycle of violent eruptions.

      870 Vatnaoldur eruption (and 234 years later) 1104 Hekla eruption (and 258 years later) 1362 Oraefajokull eruption (and 2 x 256 years later) 1875 eruption of Askja

      • I had one somewhere. Question is just if it is in my now defunct computer or in one of the laptops. I willl look.

  19. Now time to count 20 000 flying sheep and a gnome…
    I wish we had a mythological creature like that. It would be really fun to mimic one.
    Yes, we have trolls, but the size of those are to daunting to mess with. And the Tomtar (think mini santas that are grumpy and live in the barn) are kind of hard to mimic since they are too small. I would love something man sized that one could scare people with.
    And scaring the Samí people with mimicking Olmmaí Biággí (The Windman) is probably not okay either… And there we are back to the flying sheep. The Windman is a demon responsible for the weather. If he gets annoyed you get flying sheep. One of the more impressively cranky deities around really, makes Khali look benign.
    Now off to count fluffy snowy lambs in my dreams!

  20. Subsidence in kharst topology is one thing, but subsidence in a volcanic field?

    One by one, homes in California subdivision sinking

    …It wasn’t long before the houses on both sides collapsed as the ground gave way in the Spivey’s neighborhood in Lake County, about 100 miles north of San Francisco…

    Read more: http://www.foxnews.com/us/2013/05/11/one-by-one-homes-in-california-subdivision-sinking/#ixzz2T8nSlguH

    The late-Pliocene to early Holocene Clear Lake volcanic field in the northern Coast Ranges, contains lava dome complexes, cinder cones, and maars of basaltic-to-rhyolitic composition. The westernmost site of Quaternary volcanism in California, the Clear Lake field is located far to the west of the Cascade Range in a complex geologic setting within the San Andreas transform fault system. Mount Konocti, a composite dacitic lava dome on the south shore of Clear Lake, is the largest volcanic feature.

    http://www.volcano.si.edu/world/volcano.cfm?vnum=1203-10-

    Lakeport (the site of the sinking homes) is about 14 km from Mount Konocti, and is located along the Western shore of Clear Lake… which is not listed as a caldera (AFAIK), but physically, it could be. (large contiguous depression, plus known volcanism in the area… which would make Konocti a resurgent feature.) I have seen no papers characterizing it as such.

    Per CVO “probably volcano-tectonic in origin, but is not a caldera

    Dunno if they include trap-door calderas in the “volcano-tectonic” category

    • I did read about it, it is maybe the way populations happen in and around volcanoes over time and wake up one morning to natures call

    • Sounds horribly much like a bradyseism. Have they found a spot that is going the other way? That would be a giveaway.
      I guess the place is populated?

      • (“We want to know what is going on here,” said Scott Spivey, a former city building inspector who had lived in his four-bedroom, Tudor-style dream home for 11 years.)

        Go and diggeth in thine own yard, dude. Sounds like the man responsible for finding things like this out is the one getting hit.

        I have an idea. I have before talked about blockage from mines. It looks a lot like how blockage over a mine starts. I guess there was a hollow area a few kilometers down that slowly have blocked up the roof and wandered upwards.
        My five cents.

  21. First… LOOK at my avatar.

    Now consider this: “If pigs could fly, everyone would carry umbrellas.”


    I thought there was light at the end of the tunnel, but it was some bastard with a torch carrying more work.

  22. Here be a Wikipedia definition for you.

    In probability theory and statistics, the cumulative distribution function (CDF), or just distribution function, describes the probability that a real-valued random variable X with a given probability distribution will be found at a value less than or equal to x.

    In other words, if you look at an x point on the curve, the value of y at that point is the probability that something would have occurred by that point in time, if x is a plot of time.

    Here is something interesting… (well, it could be interesting, if you are into volcanoes)

    This is based off a Gaussian distribution. Poisson would probably be better way of looking at it, but both have proved to be equally poor at predicting a volcanoes next eruption.

    A sound way of reading this plot: Given it’s post 1950’s history, with the given conditions, about half the time, Hekla would have already erupted by now

    Hekla has two distinct behaviors. Post 1950, it seems to have a shorter repose period. These two distribution curves are based on 1000 year eruptive history, and on the repose periods post 1950.

    Sturkel et al gives this as a possible reason for the behavior change.

    We attribute the change in eruptive pattern at Hekla to the feeder conduit now being sufficiently large that it does not freeze in the inter-eruptive period so that only a relatively small and weak cap develops.

    “New insights into volcanic activity from strain and other deformation data for the Hekla 2000 eruption” Sturkell et al (2013)

    http://www.sciencedirect.com/science/article/pii/S0377027313000462

    Note: This would explain why the last eruption was so quick in it’s onset with minimal seismic warning. I’m not sure how it plays out now.

    And more to add… Using the post 1950 dates, the 95% confidence interval is 7.6 to 17.4 years. That means that the actual average repose period is in that range with 95% confidence. It’s a statistical measure and has no meaning other than that.

    And for the media twits that wander around. NO VOLCANO FOLLOWS A SCHEDULE. This is just conversation data between people interested in Hekla, I am not a Geologist or a Statistics expert. I’m just some guy on the Internet. If you want real, valid data, do your job, go interview one of the experts at IMO.

    I am pretty certain that they would love to talk about their field of work.

    • Care to ellaborate a bit on this in a post.
      I have a couple of comments too on the Sturkell paper. Perhaps we could cook it into one post?

      • Fell free to dress out what I have said in order to make a post.

        I have to drive (again) and won’t be able to contribute any more until later… provided I don’t get psycho and start slinging tools at people and get arrested. (low probability, you never mistreat your tools)

        • You would though get famous if you slinged surströmming at them. Although I think it should be eaten.

    • Given that it is about 30 years since I did statistics I am not really qualified to say anything, but everytime I think of stats and volcanos I run into the same conundrum:

      Stats are useless unless you have a big enough population of data. For volcanoes this means either:
      1. taking the data from a large number of volcanoes which renders any predictive power of the statistic for any one particular volcano null and void (i.e. all you get is something like, on average there will be one VEI 6 eruption somewhere on the globe every 100 years)
      or
      2. you take a large number of eruptions from one particular volcano which doesn’t really work either as most volcanoes don’t normally have a steady eruptive pattern (unless they are called Stromboli) which also renders the informative value of the statistic null and void for most volcanoes.

      So you are only left with meaningful statistics for volcanoes where common sense already tells you to be careful (like Hekla).

      • Statistically Hekla erupted on the fourth of april last year. Statistically we are now waiting for the next eruption after the statistical 2012 eruption. 🙂

        You are correct, statistics is not usefull unless you add more information into the equation. For Hekla we can add a bit of known facts to foundate the statistical prediction to make them a tad more in the ballpark.
        Problem is just that volcanoes statisticaly do not conform to statistics and that is a statisticaly proven fact. 🙂

  23. For those who wonder what surströmming looks like when you eat it.

    Image and video hosting by TinyPic

    And since Captcha has become equally cryptic as Prophetic in its phrases, this time it was “lunatic fridge”.

    • Shouldn’t that be “before you eat it?” I’m pretty sure it doesn’t look like that after you eat it…. though it may look like that as you eat it.

    • looks delicious! i’m sorry that a simple computer cannot reveal the sensory explosion that will hit your olfactory system when indulging in this treat!! Maybe we need some smell ware?

        • I would send you a can if it was not the small thing that happened last time I sent a can to the US.
          I had a swedish friend studying in the area of LA. So, as a good friend I dutifully sent him a can. Two weeks later it knocked on his door and two guys in very black suits showed badges under his nose.
          FBI was for some reason not amused about a can of fermented herring detonating in a cargo airplane mid Atlantic. So, no surströmming for you…

      • It is actually delicious if you eat it as it should be eaten. The smell is actually mainly around when you open the can. It tastes rather close to italian canned sardelles.

        • Well that’s not the reputation it has abroad. But I’m just a guy from a nation eating things like snails with garlic and host to more smelly mouldy cheeses than there are days in the year….

          • On the other hand I love snails in garlic and mouldy cheses too… Hm, might be a pattern somewhere… But I draw the line with eating french poisson and pain. 😉

  24. Deep and profound OT ruminations this morning.
    The great query about why the Gnome was crossing the road. I looked at all angles and took into account the Logistics, probable mathematical convolutions and the proximity to GeoLurking’s natural habitat and propose this hypothesis.
    “There was not mush room on the side he was on so had to move for elf and safety reasons”
    My second rumination….As I sowed my Iceland Poppy seeds I thought of Irpsit and Islander’s gardens. I also imagined all these pretty , delicate flowers nodding in the gales on Hekla’s slopes………”.What a shame ” I thought,” all these beautiful flowers being destroyed by Hekla Vomit. I wonder if these plants have a special strategy for surviving such an onslaught”
    I Googled as one does……
    Errrm! Iceland Poppies are not found in Iceland! (Unless they are planted in someone’s garden!)
    🙂

    • Icelandic Poppies are one of our faves too. They do not like NE Oregon for some reason-probably too warm/dry. We’ve had a warm-dry spring here. 30+C for a few days. NO rain…

      • Spring weather is Iceland is way colder than that. Even summer is way colder than that.

        We had most days of April, with temperatures, day and night below 0ºC. Even the 1st of May had a low of -14ºC. But May brought spring weather. The days are now 13ºC and nights -2ºc.

        Summer weather is on average 17ºC in afternoon, 7ºC by night. It almost never gets warmer than 23ºC. And Reykjavik is even colder because it is by the sea.

        • But while coastal Iceland has an ideal climate for Iceland poppies, Oregon and the UK (Diana) have much warmer climate to grow many other types of flowers. In Iceland only a few can grow outside on their own. Most require much effort and shelter from the elements. In Reykjavik it is easier to grow a garden (the climate is milder there, winters much milder, but summer cooler). Where I live we can have very cold weather in winter and spring, but summer is more pleasant, though short.

          • Summer is done and dusted after the last change coming through and so is Autum, now we have 0 – -5 or so and 13/14 for now, brrrr, lucky I just finished my outside work, now to inside, my office is only half done, will have to do for now, lounge first, then office is the next 2 weeks agenda, before it gets to cold, I live about 800m high

    • Hi Diana,

      Iceland poppies do not grow near Hekla. Only very few species survive near the volcanoes, because they are deserts of ash, and very cold, windy and harsh climates. The ash does lack some mineral and organic matter, so only very few species can survive there,

      Icelandic thyme, moss campion, Armeria maritima and Saxifraga caespitosa are some of the very few.

      The poppies grow near populated areas near the coast. They were introduced by people long ago and now they spread in a wild way,through their seeds, but only near populated areas. They like cool moist weather and gravely soil.

      • ‘The ash does lack some mineral and organic matter, so only very few species can survive there’ ,that is making me think, the area live in is a volcanic field in my book, in some parts I have not been able to grow trees, I lost three of them and I am normally good at growing things , when I dug up the soil is like you said

    • Your world is stranger than mine Diana……

      It is so cold this spring that perhaps Icelandic flowers might be better suited to our climate now 🙂

      • Lol Alyson. I never cease to wonder at the strangeness of my world 😀 Thank you for the flower information Irpsit. I was gently joking about the flowers on the slopes of Hekla. Far too cold and as you say loose ash. Not an easy place for plants to colonise. However there will be very small mosses and lichen . I know Moss is not a flower but it is an incredibly interesting group of plants. They are the first plants to colonise an area ravaged by fire or lava flows. They form the first “soils” as they die. This provides anchorage and nutrients for the next wave of colonisers, which include tough grasses and rushes. Then come the low, creeping species or strong specialised plants such as Rose bay Willow herbs . These are called “Fire Weeds” here. They are the first really tall plants that are noticed. After the last war in the big cities that were bombed badly. The Rose bay Willow herbs took over the bomb sites and brought some natural beauty and colour after the awful devastation. I am still working on a post that goes into more depth on this subject.

        • In Flanders, the corn poppies are usual the first flowers to colonise devastated area’s. This is also why they were so abundant in WW I, they were the first plants to appear in nobody’s land and bombing sites. This is of course the first flower I thought of when I read poppies. I hadn’t heard of icelandic poppies before. So I learned someting new.

    • Yes, first time, at least in 3 years I follow Icelandic quakes, a quake in Fremrinamur!

      And also (yesterday), a first time a quake in Veidivotn, at a spot where we haven’t seen them yet. Which is way more near the chamber of Hamarinn.than those ocasional quakes near Torfajokull that sometimes we see.

      This shows two quite dormant volcanic regions coming to life 🙂

      Say “hotspot pulse”, say with me “hotspot pulse”…. ,)

  25. If anybody wonders how it looks at the tremor graph when something out of the ordinary happens, here is an example from the 28th of april (and a small something from the fourth of may). This is from Grimsvötn. What exactly happened is a good guess really. Either it is a harmonic tremor spike from a dike emplacement. It could also be a phreatic event, a geothermal event, or a large body of water that moved. It might even have been a minimal eruption. Whatever it is, the important thing is the very rapid and brutal increase in tremor levels, also the sudden shift in what frequency of the tremor is showing the largest increase. And finally, the amount of energy released. Compare it with the storm 5 days before. It was a large storm. Slow increase, only low frequency increase, and rather modest energy increase compared with a real event.
    If this had been an eruption the energy release levels would have been brutally much higher. But it is a very good image anyhow. If you have this in the back of your head you will have a good idea of what too look for when a volcano erupts.
    Note that the quake swarm at Tjörness, or the recent one from Reykjaness shows more then as thin red spikes.

    Image and video hosting by TinyPic

    • Yes, I can see it. Very interesting, especially when coming from a volcano that usually erupts in shorts intervals and is so intimate to the mantle plume beneath…
      And now Carl, have you heard of this ? – “Earth nucleus supposed to spin in different speeds from those of the mantle”? Have just read it a local news in the internet:
      http://noticias.uol.com.br/ciencia/ultimas-noticias/efe/2013/05/13/nucleo-da-terra-nao-esta-sincronizado-com-a-rotacao-do-planeta.htm
      If it is so, I wonder what sorts of influence does the phenomena has on magnetic field behaviour, convective plumes and so forth…
      Especially interesting that of the “double earthquakes”.
      It’s in Portuguese, and very superficial, hope somebody has more to say about it.

      • It is also hotter then previously believed, which actually makes my hypothesis of core plumes more probable. Core plumes is a working hypothesis I have to explain anomalously large magmatic iron emplacements (ie. the Kirunawaara Iron Ore Body).

          • maybe core plume only goes to the lower mantle – and that then in turn spawns mantle turbulence?

          • Problem is that I think I know where one actually got to the top.
            Most iron mined on the planet are banded iron deposits. This iron is oceanic in nature and consist of iron oxide that settled on the bottom as the first life started to produce oxygen to kick start the rust formation. This band is between hundreds to kilometers in height.
            The Kirunawaara Iron Ore Body is magmatic in origin. But has a brutal purity. And the size of the deposites are huge. The known deposites are enough for humanities needs for a quarter of a million years.
            Only problem is that the earths mantle can’t be the source since it contains to little iron. We know this from all other eruptions. So, however I bandy things around I am stuck with the idea of at least one core plume having happened in the crusts history.
            Note, the Kirunawaara body was emplaced into and through the Baltic craton.

            • So…………………..

              Is this a feeder plume for Etna at 278km depth, or something entirely unconnected???

              2013-05-14 02:59:03.08hr 09min ago 38.92 N 15.37 E 278 3.4 SICILY, ITALY

            • Normal depth for quakes in the region.
              I saw 650 km deep quake in the Mariana Island region in the morning.

            • In a discussion with “Passerby” over on Eruptions Blog… before it went to wired, and possibly before BigThink, the idea of a subducted plate fan-folding as it entered the slab graveyard came up. Portions of the plate that are still somewhat rigid, can generate quakes as it breaks up at extreme depth.

  26. Two solar X flares within the last 24 hours. geographically a very boring period with very little quakes or tremmors…….

    • Popo is not a fun volcano.
      If one looks through the GVP list of large eruptions it pops up time and again with VEI4 and above eruptions.
      It is not a volcano to toy with and it is good that the authorities are ontop of it.

      • It’s a very large subduction arc stratovolcano. I believe it’s predominantly andesitic, but can also produce dacitic eruptions (recent eruptions are supposedly mixed between the two).

        In other words, just about anything *can* happen. I think the greatest risk that doesn’t involve a full scale caldera collapse event would be an edifice failure or debris avalanche.

        Right now, I believe it’s just going through dome growth and destruction, which usually leads to strombolian style eruptions for a long time, although the question of whether this can escalate into something larger remains at large.

        One thing that’s interesting about Popo is the sheer size and height of it. How much larger can it get before it becomes structurally unsound? Volcanoes like Kilamanjaro and Hawaii show that volcanoes can get really really tall, but those have much much shallower slopes and a more mafic magma.

      • “…it is good that the authorities are ontop of it.”

        That would be a bit foolhardy don’t you think? On second thought, maybe the top dog authorities should be mandated to spend the majority of their term literally on top of the nations most active volcano… complete with staff and cabinet members, aids, and interns.

        • I am fully for the idea to move all legislative and executive powers to a position ontop of an active volcano. Would keep them on their toes, and remind them of the small fact that they are puny mortal humans we “regular joes” are.

  27. I found this nice site. It has all data since 2005 about icelandic quakes. It’s all in dutch so i’ll translate as i go along.

    It’s easily accesible in two forms. First you get data from the most active area in iceland. depth nz, ew, depth and magitude.,

    On “overige deelgebieden”you can select other active areas.

    Check “deel-info” tab(3) for shure. You can move a square over the country and see a nice bargraph bout the numbers of qaukes for the last 12 years and more detailed over the last year.
    http://www.ijsland-enzo.nl/ijsland/actueel_beving.asp

    Check tab 3!

    Works like this. Press reset . Mouse move square to position. Press ok button.
    
    I contacted the owner of the site and he says he ready for you guys and girls looking around his site!

  28. Something curious just happened.

    Today we have one of the strongest flares of this solar cycle. http://www.spaceweather.com

    And I think we are about to experience the peak of the current solar maxima. This is an important astronomical moment. Usually not a big deal, except for northern lights and ocasional electrical or radio disturbances.

    Supposedly it is (and will be) a weak maxima (less sunspots and less flares in number), but sometimes weak maxima can have the most powerful record-breaking flares like in 1859 (Carrigton event).

    And as I was typing this, the lights wane and electricity was off. Electricity comes again, except for internet and tv which do not receive signal for a few mins. Since I was just typing and thinking about the upcoming solar maxima, was this a curious warning sign?

    Or probably just a flirting coincidence. The universe likes to tease us.

    • Correction: when the lights went down, I was just typing the Carrington event. Ironic no?

      By the way, I dreamt this last night about a massive eruption in Iceland under Vatnajokull with a nuke like cloud appearing on the horizon. Something which I actually saw back in 2011.

      as I say, I do not think all coincidences have meaning. Life likes teasing on us.

    • Irpsit,
      Today’s X-flares are probably the expected “second peak”. The first (primary) peak occurred last year..earlier and much weaker than expected. At that time, solar experts predicted a possible second peak (as occurred in previous cycles), and these two x-flares may be part of the second peak. Too bad they weren’t on the earth-facing side of the Sun. Nothing but good science, but little else from these events.

      • Another x-flare just now (3rd in sequence). Looks to be the strongest of the three. The active region is just starting to rotate into view (earth-side). More strong flares are possible.

        • Geolurking, we are currently in cycle 24. The current cycle already had one peak and this would be the second one.

          But it seems that weak cycles, like cycle 14 was, have two or more peaks within the maxima.

          Some models by NASA have shown that a new peak is predicted for late 2013, early 2014, and if my memory is not wrong, another peak to occur later by 2015 or 2016. Then, the next minima comes, which could be very strong minima (which could reduce global temperatures due to reduction in global solar output)

          • Yes, I am aware that we are in 24. My point was that multiple peaks can occur.

            Generally speaking, there are two peaks in a cycle. These come about from one Solar hemisphere peaking, then the other hemisphere.

            As for the reduction in solar output, you’re getting into the TSI (total solar irradiance) can of worms. People will fight you over that. Alone, TSI variation can’t account for the temperature shift. Henrik Svensmark postulates that the increase in galactic cosmic rays (GCR) during low solar activity (due to a less energetic solar magnetic field) seeds cloud formation and changes the earth’s albedo. This then reflects more solar radiation and acts as a forcing mechanism, making the drop in solar radiation more significant.

            CERN did the CLOUD experiment to see if there was anything to it. There was, but according to their results, there had to be nitrogen compounds present in order to facilitate the seeding of droplet nucleation. The level of nitrogen needed is well within the normal background level found in the atmosphere.

            Now… even though the sun is laboriously crawling to and through solar max, data from Livingston and Penn seem to point to an overall drop in sunspot intensity. Apparently, the magnetic flux tubes (which form sunspots) are diminishing in intensity. Weaker flux tubes evacuate less plasma from the sunspot core, and make them less dark. Below about 1500 gauss, they won’t be strong enough to be visible. They field intensity is measured by Zeeman splitting of the spectra in light from the “dark” regions of the sunspot. (they appear dark due to the brightness of the rest of the suns chromosphere)

            The trend has held up for several years. The big question is if it is a normal cyclic function of the sun or is something else going on.

    • I make a prediction.
      During the solar flares I will fall asleep several times.
      I also make a prediction. Only countries with underserviced and overused electrical systems will notice it.
      One of these predictions is humorous, the other scientific.
      Todays brain-teaser: Tell which which is which 😉

      • Well, I agree with that for most solar events, but in the scenario of a Carrington like event, although occurs only an average once per 500 years (last time in 1859) could probably have a serious impact on a well developed country, especially those in northern latitudes.

        Still the only destruction that such an event (or a larger one) could cause is only to electrical grids. In billions of years, never such a flare apparently had a direct impact on life. At least that we know it from geological records. Only large meteors, large volcanism and large climate change, seem to have such impact. Our Sun seems to be a fairly calm star compared to other stars that flare in a way that would totally fry our planet, if they would happen on the Sun.

        • Actually i might be wrong!

          Some researcher think that, accordingly to geological phenomena, a mass extinction of the megafauna in the Pleistocene might have been caused by strong solar flares, larger than the Carrington event. The hypothesis is there but there are other hypothesis such as a meteor impact.

          Evidence for a Solar Flare Cause of the Pleistocene Mass Extinction
          https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/3464

          If this theory is true, its not only your “underserviced and overused electrical systems” that will notice. It would be a disaster for everyone.

        • As I read more and more about the late Pleistocene mass extinction event, it seem that certain things happened as they come up often in geological data:
          – very sudden and dramatic climate change, disruption of the ice caps, flood occurring, all within a very short period of time
          – presence of extraterrestrial elements such as iridium, amonium and nitrates
          – massive fires in north america.
          – no clear indication for an impact crater
          – anomalies in the radiocarbon levels in the atmosphere

          this is the data, without any theory linked.

          Theories go for 1) a meteor impact (that mostly exploded over north america), 2) strong solar events, 3) it can also be something different

          • Carolina Bays… ever hear of em?

            Image Source: Wikimedia

            If there was an impactor, my belief is that it was mostly a breakup somewhere over the Pacific NW, and blasted debris across North America.

            Plotting the intersection of a few of their long axis, they converge in that region (Pac NW)

            It also would have messed up Clovis civilization pretty well.

            Hello Younger Dryas…

      • @Carl and all. An interesting read by Willis Eschenbach over at WUWT.

        In it, he mentions the wild idea about radioactive decay constants possibly not being constant. An yes, he does cite the sources for that realm of ideas. Purdue University seems to believe that they can predict solar flares from this phenomena.

        Jenkins, monitoring a detector in his lab in 2006, discovered that the decay rate of a radioactive sample changed slightly beginning 39 hours before a large solar flare.

        I’ve always found Willis Eschenbach’s musings to be entertaining and informative.

        • The constants are constants, but the thing that affect radiocative isotopes forming and spreading can vary a lot.
          C14 for instance varies a bit depending on if earth has passed through a comet tail recently, or any other sort of interstellar carboniferous cloud.
          Also, the sun has a tendency to whack out isotope byproducts at an uneven pace. Even our dear terrafirma has a tendency to be rather episodic in how it dumps Ur/Th into the atmoshpere due to volcanic activities.

          The radioctive sample detector most likely detected sun related hard radiation particles being broadcasted before the visible matter was released.

          About once a year someone comes up with decay constants not being constant. It always boils down to one of two (I got into more in the end) things. Experimental contamination (most probable in this case), and decay probabilistics misunderstandings. The last is devidable into two subgroups (erroneously believing that isotopes are evenly spread and evenly released into our environment), and secondly believing that statistical decay is the same regardless of sample size (it is often not) and the bonus version, not understanding that it is a statistical occurance at all. You need to average bunches of same sized samples…

          I got the feeling that the guy pretty much messed up in all possible ways here.

          Ah, bonus bonus… temperature variations in the room, radiation variations in the room (a roof lamp giving off UV-light can give a different reading than a roof lamp not giving off UV, a radio source… well, pretty much anything can affect without making the constant non-constant.

          All the things above gives that famours spread in the probabilistics funnel infered when using any isotope dating. The 2000BP +/250 for C14-dating for instance.

          What really would make me jump was if it started go the other way all of a sudden. Let us say that one kg piece of sollid uranium all of a sudden had half the isotope decay for an extended time.

          For those who have a geiger-counter and a concrete wall. Stick it to the wall and sit and listen to it for a week or so. Just the weather variations will give you pause for thought. The radon released will vary with a factor of 100 depending on your weather, and if you have a thunderstorm it will get really interesting…

          Just remember, statistics is a bitch that bite even seasoned physicists in the arse often enough. 🙂

          • I figured you would like that. 😀

            Reminded me of when one group found a signal that traveled faster than the speed of light. I think it turned out to be an issue with satellite transmission path times (latency) not being properly accounted for.

            • I think it was latency timing too. But my memory is not always the best. 🙂

              My favourite experiment is the CD that disappeared. Some dudes at CERN had a bit to of time on their heads so they concocted a wild arsed experiment into teleportation. They wanted to disprove a certain method for sollid materia teleportation.

              They set up the poor CD (with music of Beethoven) and bombarded it with a GR (giga-ridiculous) amount of energy, and opened the test chamber. Nobody has sofar A) seen the CD, and B) been able to get the same result. Experimental physics is also a bitch the bites the arse of physicists now and again. 🙂

              I should mention that they had not put up any equipment to check for either gas release, nor to check for radiation or particle release, this was the test run of the GR releasing equipment… So, nobody knows what happened and will most likely never know.

            • Hmmmm… If I remember correctly, Venkman and crew thought the same thing about Gozer (totally disappeared after being hit with the proton streams)… only to have the StayPuft Marshmellow man show up shortly afterwards.

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