Volcanic Winters


Guest Post by Albert:  Weather is changeable but climate is forever. At least so it seemed, before the global warming began in earnest in the 1980s. The difference between weather and climate is often lost on us: we experience and remember the weather but changes over decades are hidden from us. Nature is different: flowers appear weeks earlier than they used to, in response to a warming we haven’t really noticed. But there are short term fluctuations which we do feel. These happen over six months to a few years, and change the weather notably, but are too brief to affect the climate. In the UK, the exceptionally mild winters of the last two years come to mind, or the three rather colder winters preceding them. In other places it can be years of drought. Often they are local events only: for instance, the last winter was very mild in Europe, very cold in parts of the US, balancing each other out. But sometimes they do trace a real, brief change in global temperatures. There are two main events which affect global temperatures on these time scales. One is the El Nino: it occurs irregularly and releases enough heat from the oceans to make a notable difference, lasting 6-12 months. The other is volcanic eruptions, with Pinatubo, Krakatoa and Tambora well-known examples. Pinatubo depressed global temperatures for up to two years. Tambora gave a larger change lasting a few years. But there are times when temperatures go up or down for a few years without a clear volcanic cause. And there is disagreement on how strong volcanoes need to be notable. I tried to find these effects in the global temperature records. The figure below shows the so-called Annual mean Land-Ocean Temperature Index which I consider the best one to use. (There are other temperature indices: some only measure temperatures on land which is closer to our experience but more prone to weather.) I have split it up over the northern hemisphere (above 24 degrees latitude), the southern hemisphere, and the tropics. Comparing temperature graphs immediately shows that the northern hemisphere, and in particular non-tropical latitudes, are most affected by variations. The southern hemisphere is much more stable. This shows the stabilizing effect of oceans: the southern hemisphere is mostly water, and water has a much higher heat capacity than either land or air. Land can respond quickly to changes, but oceans require a long time to heat up or cool down. century_temp_NS The arrows at the bottom indicate larger El Nino’s. The very strong El Nino of 1998 is clearly visible. But how well are volcanic eruptions visible? The figures shows the main eruptions over this time. The largest ones are Krakatoa (1883), Novarupta (1912) (the name ‘Katmai’ is also used), El Chicon (1982), and Pinatubo (1991). I have also added the VE5 eruptions, as shorter lines to distinguish them. Furthermore, colour is used to show whether they erupted in the northern hemisphere (red), tropics (black), or southern hemisphere (blue). Pinatubo is clearly visible in the temperature record, in all three plots. El Chicon is not, but it coincided with a very strong El Nino which may have canceled its effects out. Novarupta had no effect. Krakatoa mainly affected the northern hemisphere. Some of the other volcanic eruptions coincided with a temperature excursion, but it is hard to be sure this was not a coincidence. The ones under suspicion of climate alteration are Tarawera (1886; southern hemisphere only), Bezymianni (1956) and Mount Agung (1963) (but the bad winter of 1962/3 came before this eruption and cannot be blamed on a volcano). The Cerro Azul (1932) eruption came before a cold year, but went off in the wrong hemisphere, so is above suspicion because of a good alibi. Hemisphere is important. It is very difficult for northern eruptions to affect the southern hemisphere and vice versa: the tropics act as a very effective barrier to the spread of stratospheric sulphur. Volcanoes in the tropics have an advantage: they can spread their pollution to both hemisphere. The rule of thumb is one of contrast: for a proper volcanic winter, you need a tropical volcano. Can we go back further in time? The temperature record becomes more difficult: there are too few direct measurements, and you can’t use say the long records from central England as they are far too localized: you would get weather rather than climate. However, there are other methods, such as tree rings, and Greenland ice core records, which can be used. They don’t quite measure temperature the same way and you wouldn’t expect a perfect agreement. But it has been shown to work well enough. The temperature record over the past 2000 years is shown below. The red line overplots the recent accurate measurements for the northern hemisphere. Note that all temperatures are shown against the 1951-1980 global average. millenium_temp The Little Ice Age, from about 1300 to 1800, is easily visible. There are also numerous brief excursions. Are any volcanic? To find out, one needs a list of major volcanic eruptions over the past 2000 years. Amazingly, this does not exist. Most major volcanoes erupted in places without a literate population, or, worse, wiped them out, and people just didn’t think of recording the ‘VE’ number for each eruption. Very inconsiderate. But ice cores come to the rescue. Volcanic ash and sulphur leave their traces in the ice, and can be identified both from Greenland and Antarctica. The years can be a little uncertain (it is not easy to accurately count that many layers), the eruption magnitude cannot be accurately inferred, and the location of the volcano is anyone’s guess. (Although it is possible to infer whether it was a tropical, northern, or southern volcano, depending whether it is seen in Greenland, Antarctica, or both.) A list of eruptions and associated volcanoes is in below. Before 1600 there is considerable uncertainty in date, identification, or both. The Kuwae eruption was possibly the largest of the millennium, exceeding Tambora. The 1808 eruption is unusual, in that a fairly accurate date is known (early Dec 1808) but there is no proposed location. Quite a few of these eruptions coincide with a temperature drop. Before 1452 the dates become more uncertain and you wouldn’t expect to see much of a correlation. The excellent fit in 535AD is a bit misleading, since the temperature decline was used to date the eruption! However, there are enough cases of real agreement to make the case for volcanic winters convincing. But not really winters. The sulphuric haze reduces the strength of the sun light, and this should have more effect on the summer temperatures (when the sun’s effect is strongest) than on the winter. A volcanic winter is typified by snow in summer. Extreme winters can rarely be traced to a volcano. The cause of the winter of 1740, when the Shannon froze over and a quarter of Ireland’s population died, lies out in the Atlantic, and not in sonme distant caldera. Not all weather excursions can be blamed on volcanoes.

Year Volcano Location Indicative VE
1991 Pinatubo Philippines 6
1956 Bezymianny Kamchatka 5
1912 Novarupta Alaska 6
1902 Santa Maria Guatemala 6
1886 Tarawera New Zealand 5?
1883 Krakatoa Indonesia 6
1861 Dubbi Eritrea 5?
1854 Sheveluch Kamchatka 5
1831 Babuyan? Philippines 4
1815 Tambora Indonesia 7
1808 unknown tropics 7?
1737 Tarumai Japan 5
1667 Tarumai Japan 5
1641 Awu Indonesia 5
1600 Huaynaputina Peru 5?
1570 Billy Mitchell Papua New Guinea 6
1482 Mount St Helens USA 5
1452 Kuwae Vanuatu 7
1351 Tarawera New Zealand
1257 Samalas Indonesia 7
1026 Baitoushan China 7
902 Ksudach? Kamchatka
702 Bona-Churchill? Alaska
535 Llopango El Salvador
232 Taupo New Zealand
  • 1831: The identification with Babuyan seems doubtful. The dust/sulphur is seen only in Greenland, not Antarctica. Also the dry fog reported in Europe that year suggests a northern location, perhaps North America. There may have been two eruptions, one around 1830 and one around 1835.
  • Long Island, Papua New Guinea, may be another candidate for the 1640 eruption. It had a large event sometime before 1700.
  • The identification of the 1570 dust as from Billy Mitchell is tentative. The eruption itself is not accurately enough dated.
  • The Baitoushan eruption has an uncertain date by +- 50 year.



108 thoughts on “Volcanic Winters

  1. Many Thanks Albert, a very timely post. I have been listening to a course on the Neolithic Revolution and found a mention about a cold wet spell from 3100 BCE to around 2850 BCE that was on a level of the LIA to be quite interesting. Towards the end of that period was about the time that the Windmill Hill culture started dragging Sarsen stones around. Mentally, there would have been a connection with the moved stone to a better crop yeild and the sudden appearance of newborns nine months later. In later years, the cultural memory of the association with fertility and the stones would lead ministers to organized activities to destroy the “devil stones.”

    Personally, I think the fertility slant still exists in modern cultures. Midsomer is still celebrated in Nordic countries and you can see a spike in conception times around June in the birth rates. I have yet to look at Sweden Finland and Norway data, but it shows up quite well in the Åland Islands. Being situated between Finland and Sweden that makes it pretty Nordic. 😀

    The US seems to have a similar spike in November. In my opinion, this is due to the US being centered more along the idea of harvest festivals. In both cases, people are getting together and mingling. New liaisons are formed and nature takes its course. As a teen I was always eager for the State Fair in November because it invariably arrived during the first cold-snap and you were sure to have to snuggle with your date to stay warm. (yes, guys think like this… always) For the people that moved and lifted a stone into place, it would have been a community effort. Cattle that were used for making rawhide ropes would have been cooked and eaten and in my opinion, it was probably like a several month long bar-b-Que. To this day, the US still shows an increase in conceptions in the May-June time period, though it is not as strong as the November spike.

    Raw Data Source: http://data.un.org/Data.aspx

    ...Listen! red light, yellow light, green-a-light go!
    Crazy little woman in a one man show...

    • I guess no one noticed that the drummer only has one arm. The song was released in 1987 and he lost his arm in an accident in 1984. I’d say that he has overcome the issue quite well.

      On 23 October 1995, the band entered the Guinness Book of World Records by performing three concerts on three continents in one day (Tangiers, Morocco; London, England; and Vancouver, Canada).

  2. Now, back to the topic at hand. The Earth has some large scale circulation patterns in it’s atmosphere. These are relatively persistent flows. The Hadley Cells lie either side of the Equator. At the Intertropical convergence zone (between the cells) the general trend is for air to flow upwards towards the tropopause. At around 30° North and South, the trend is downward towards the surface. At 60° North and South, the trend is again upward the tropopause. What this means is the the effort needed by a volcano to loft SO2 to the stratosphere, (above the tropopause) is not as great. The “Bad boys of Kamchatka” and the Icelandic volcanoes do not have to expend as much effort since they are near 60°N. The tropopause is also generally lower at these latitudes.

    Note: The Junge Layer is also known as the “Stratospheric aerosol layer.” When heavily loaded, it has been known to split into two layers.

    • Great post and comments. Note to everyone here-I have set my tomato plants. The “Bad boyz
      of Kamchatka ” seem to know this. Nice crepuscular sunsets in early August-and no Tomatoes-at least red ones….

  3. Thank you for the great post, Albert. Much food for thought – I imagine that, these days, any weird weather following an eruption will be blamed on that eruption, even if it’s a small one.

  4. Many thanks Albert. I like the list of Eruptions… That’s most helpful. Could we perhaps keep that ready to hand up in the Dragon’s Hoard?
    Yes it’s important to keep reminding people of the difference between climate and weather. Judging from today’s meteorological performance in Northern England we are in some sort of winter but I think it’s weather related rather than climactic.!!!
    Lurking have you an explanation as to the dip in your US conceptions Month mid April. I cannot fully correlate it with Lent let alone Easter! Funnily enough ,biologically , especially in the avian world This is the best time for conception so the young are hatched/born at the beginning of warmer months that should provide sufficient food.
    Another super VC post 🙂

    • Working nine months on from mid April brings us to Mid January…. coldest and most miserable time of the Northern hemisphere year and time for paying all the heavy tax, fuel and post Christmas checks/bills. Maybe we are still subconsciously and biologically driven by basic body rhythms. 😀

    • Well, this is a conception curve. The birth month has been backed up by nine months to find it. As for mid April? Well, it’s a month by month tally, so that value is for all of April. What happens in April in the US? Tax forms are due on the 15th. Many people aren’t really into being romantic when the oppressive heel of government is on their neck and they are coming to grips with just how screwed they really are.

      I don’t have a breakdown for individual states in the US, but for quite some time, there was a bit of festivity in May. Complete with Maypole dances and such. I brushed up against it on a tour at Natchez MS where an antebellum period Maypole Dance was presented as part of the tour. If you are into architecture, specifically that of the old south, I highly recommend the tours in Natchez MS. It’s about the only city that wasn’t burnt to the ground (Like Jackson MS) during our civil war. If I remember correctly, only one house in Jackson wasn’t burned… along with the old capital building which was used as a stable for Grant’s troops. (it’s a museum now)

    • Interesting. Current Pan troglodytes have been known to use a stick to collect termites. Maybe finding a use for an item is the genesis of forming a purpose driven tool.

      • I’ve held for years we know little about the capabilities of ancient humans. Also the boundaries
        of what is human. For years, Neanderthal was thought to be non-human then barely, the we
        (of European and central Asian extraction) have GrX10 33rd. Granpa Oog’s genes in us.
        -wife gives me a bad time for going barefoot with shorts and t-shirt even in pouring rain..-
        My reply is: “Well our ancestors did this in either a Kilt (Highland Scot) or a loincloth (Eastern
        Native American) …” i attribute this to ‘Ol gramps Oog…

        • I agree that the boundaries of what is human is a puzzle. When I was a child it was defined as ‘tool-using’ – then, as Lurking says, chimps were discovered using tools. Corvids (especially crows and ravens) have also been seen using twigs to winkle out food. We can’t say language, because many species vocalise to communicate and out version is just more sophisticated. Personally I think we’re just over-achieving great apes, but others may have a different view! 🙂

  5. Thank you, Albert 🙂

    Couple of questions:
    1. How much does annual rainfall affect both tree – ring growth and ice samples?
    2. There is a VEI 4 in the list of eruptions. I have not checked but there must have been more than one in that time frame. What was the rationale for excluding the others?

    • Good questions! Tree rings measure growing conditions. Poor years can be due to temperature or lack of rain, but temperature is normally more important, I think, depending on latitude. For the ice samples, the temperatures come from isotope analysis, not from the thickness of the layer. But if there was no snow at all in one year, or everything melted during the summer, there could be a year missing. Both are unlikely on a thick glacier though. The glacier is there for a reason.

      The VeI4 in the list is the magnitude assigned to that eruption, but there is significant doubt that that eruption is the one responsible for the dust layer. The real eruption, from a sneaky volcano somewhere in hiding, may and probably was bigger.

  6. One thing worth noting – 1258 Kuwae Vanuatu 7

    This eruption was actually from Samalas in Indonesia, and is likely the largest eruption in the last 3000 or so years.

    • You are right that it wasn’t Kuwae: that was a copy error on my part. The field was meant to be empty. But Samalas is a good candidate, not proven but not unlikely. Perhaps GL can update the table?

      • Eh? To blank or to Samalas?

        “Right now, if the match is with 1-2 percent in silica and alumina and <5-10 percent for all other major elements (like Fe, Mg, Na, K, Ca), then you can be pretty confident that the distal ash and the one from the source are the same (see below). In this case, it looks like the ash sampled from polar ice cores and the ash sampled from Samalas deposits are well within those ranges, so another piece of evidence implicated this long-lost volcano."


        “(* Further work by Clive Oppenheimer on the record of this eruption in the ice cores suggests that the date of the eruption should be 1257 A.D. +/- 1 year. So, I’ll start calling it the 1257 A.D. eruption from here on in.)”

        The Doctor (Clive Oppenheimer)

        And an amateur’s (me) rendition of the sulfur spikes in question.

        Why the heavier spike in the Northern Hemisphere? Probably due to weather. (see parent article above about the variability that weather can give you) Where the ITCZ was at when it went off likely has a lot to do with it’s sulfur signature. Samalas is at 8°25′00″S latitude, so it’s within the drift range of the ITCZ.

        • The paper dates it to May-Oct 1257 from the ice core. But the radio carbon dates of the eruption site spread around slightly older dates (1150-1260) which they say is because trees in the area are very long lived, so the wood they sampled would have been a bit older than the eruption. The do find a cut-off at around 1260. Given measurement uncertainties, I don’t think they can quite rule out a slightly older date, and there are two other volcanic spikes in Greenland (1227, 1205). These are much smaller though. To clinch the identification, they should rule out those. But the weight of evidence is on their side (perhaps not at 99% confidence) so it should be put in the table as the likely source.

    • Back when Eyjafjallajökull was doing it’s thing, everyone was jumping up and down about Katla. Looking at the eruptive history, I came to the conclusion that the excitement was for nothing. Every time that Eyjafjallajökull went off, Katla was just coming off of an eruptive period, or was already on it’s way to one. If I remember, Katla was always within about 10 years of erupting, or had erupted recently.

      Katla getting restless now would be well within her normal behavioral patterns.

    • Dunno. When I last looked at the earthquakes under Mýrdalsjökull (while I was downloading stuff for Holuhraun so week 33 to 50 ish 2014), there may have been a stack from 50 km (depth from memory). I don’t have the data to hand at the moment. Has anyone got more up to date / more reliable info?

    • I don’t think she was ever really asleep. The activity we’ve seen at Katla within recent months hasn’t been anything out of the ordinary, not to mention the phreatic eruption that occurred in 2012.

      Statistically speaking, Katla is as close as it gets to old faithful – it has erupted somewhere around 50+ times in the last 10,000 or so years, with less than 10 of those eruptions having a repose time of longer than 110 years. The majority of the eruptions fall within 90-110 years of repose time, typically erupting as VEI 4ish sized eruptions.

      We know from history that Katla behaves much more similar to Bardarbunga prior to erupting than it does Grimsvotn or Hekla. It will likely quake significantly prior to erupting (at least from the knowledge we have). The one thing that did interest me recently was a deep swarm, representing an intrusion here. Of course, this may happen quite frequently in a volcanic system like Hekla.

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

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

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

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

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

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

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

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

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

    • Very interesting and informative. Thanks for posting. Perhaps this could be expanded into an article?

    • Andrew I think you are spot on. I have also been watching Katla and noticing the deeper quakes. We are so lucky to have access to IMO monitoring as we can watch the slow development of an eruption for in my opinion this is what we are seeing. I have been watching her pretty well daily since Eyaf. ceased erupting. Firstly because of all the hype that she would “blow” soon after Eyaf. Well she didn’t but she has been gathering energy. I’d like to see if there is any change in the Cauldrons (The circular cracking and sinking of the ice over the tops of the volcanoes) They give indication of increased geothermal activity.

    • True. What is odd is that they didn’t take a clue from the way that NavMet does their exercises. The message traffic and graphics are clearly labled as EXERCISE. This is to keep from freaking people out because Homo Stultus never seem to check to see if it’s real or not.

      … and then you have the moon-bats who will use it to hype an alarming post just to get some perverted gratification out of scaring people.

  8. Geolurking, great post.

    I think the climatic impact of a VEI5 is too tiny to ammount to something significant. Unless it’s a very gaseous eruption like Laki. And even a VEI6 like Pinatubo only shows as a very minor effect.

    I think what we all agree is that a low VEI7 is the minimum intensity to see some major climatic disruption.
    Examples would include the eruptions in 535 in El Salvador, the 1258, the 1600 eruption and the Tambora in 1816. Especially the impact of the 535 eruption was devastating, while Tambora was not as much.

    From the graph we clearly see how the 20th century climate warming is more of a significant trend than any volcanic impact. Also the 30 year-ish oceanic current oscilations and their impact in the climate shows quite well in the graph. Note how the climate was warming in the 1930s, cooling in the 1960s and warming again in the 1990s. It could cool a bit again in the 2020s, and against the background of global warming it’s going to be interesting to see by how much (especially as a long-term solar minimum is also occuring).

    Other than that all variation is just the randomness of the climate, which seems larger than most volcanic impacts, and such random variation is also caused by el ninos and other climatic stuff, like negative NAO, etc.

    Finally, I always think that the abnormal cold weather by 1955 and 1962-1963 was caused by the detonation of the two largest nuclear tests ever conducted, Castle Bravo and Tsar bomb, but with only two megatests to analyse, data is defficient to assert such a conclusion. That is just my pet theory.

  9. Katla is certainly waking, down under.

    I think it is going to be a close contest between Grimsvotn, Katla and Hekla, for the next Icelandic eruption. And of course we need to monitor Bardarbunga vicinity and Askja.

    But usually eruptions start with swarms of very deep quakes. And especially larger ones.

    Very deep (around 25km deep) quakes occurred near Kistufell earlier in 2014, some months before the eruption in Holuhraun and again just a few days the big swarm began in Bardarbunga. With Eyjafjallajokull deep quakes began 3 months before.

    Now Katla is finally having the deep quakes.

    I remember that in 2011 I was one of the few that had the opinnion that Katla would NOT erupt that year, because of the noticeable lack of deep quakes of the 2011 swarms. Hence Katla did not erupt (or it did but very minor and only subglacially). In 2011 the quakes were rarely below 5km deep. Thus there were no magma movements btween the mantle and the shallow Katla chamber. Hence no eruption.

    Now, Katla is having deep swarms around 20-25km. That’s MAGMA movements for sure. Between the mantle into Katla chamber. These are magmatic intrusions. Single isolated intrusions aren’t anything special. But if they happen repeatedly they might be the most important sign to watch out prior an eruption.

    With Bardarbunga and Eyjafjallajokull such deep swarms began a few months before the eruption and continued intermitently. With Katla we could speculate whether an eruption would occur by July-September, if it follows similar fashion: if deep swarms (magmatic intrusions) continue in months ahead.

    Nearly always this is the case. But exception do occur. I can only think of Askja in Iceland. Askja has been having some repeated intrusions since 2007, though not that often. That might b because its chamber has been nearly emptied in 1875 and so there is a lot of space for magma to fill up in the chamber. But if such intrusions would occur repeately within a short period of time, I think Askja would erupt as well.

    So, there you go. I would bet 90% that if Katla continues this pattern, then it will erupt this year. But only if it continues this pattern (repeated intrusions – deep swarms – within a period of 2-3 months)

    What would I expect: a 1-2km3 eruption. I think it is quite expectable that this eruption would be big because of its longer repose, but Katla rarely does something above 2km3. What could be a larger worry would be a Edlgjá eruption, especially after the large rifting occured in Vatnajokull, but I think this would ONLY occur if we would start to see repeated swarms of deep quakes along the Edlgja rift. So that’s a much lower possibility event.

    Hekla and Grimsvotn are exceptions, in that they erupt without much warning. They erupt often and magmatic pathways are open. Both show signs of restlessness but with Grimsvotn I think it follows quite strickly the rule that it erupts promply and only when a specific ammount is reached of seismic accumulated energy since last eruption. This seems to be set to be only by mid 2016.

    Concerning Oraefajokull it is a case to watch out too. Like Askja it has been having deep quakes ocasionally, but nothing like a swarm and nothing that often to herald a warning. Though I think this volcano might be in its run-up to an eruption within a few decades. And she is a very big one.

    In conclusion, we might have an eruption of Katla even this year (not saying so), and an eruption of Grimsvotn one year from now.

    • Hi irpsit. . Good to see you again. Hope all is well in your new home. I just added a comment further up there on a similar but less detailed vein. I remember all the discussion and the comments about little clouds drifting over Katla and the usual advice that when she erupts it will be more than little white sheepy clouds 😀 😀

  10. I don’t know if this video has been referred to before but I have found it a very useful aid to understanding the Icelandic glaciers. It’s a 30 minute long film and demonstrates beautifully how the glaciers “work” Particularly dramatic and informative are the shots at the end of the great Jokulhlaup in November 1996. It’s particularly interesting because it shows how the expected flood didn’t happen until well beyond the expected time. Rather like the non appearance of the floods expected at the beginning of the Bardabunga eruption.
    I don’t normally like the background music to some of the videos about Volcanoes but I found the music very apt. I’ll say no more except that for those who have only just discovered the fascination of Iceland this video will enhance your understanding . Just watch and enjoy even if you are some of our “old Timers” I am sure it will give you more food for your thoughts.

    • Thanks Diana. Always interested in watching about these things. 🙂 I imagine back when the inhabitants first saw ‘fire on ice’ must have really been something to see. They lived on their farms not realizing what they lived next to.

      • Yeah! Sort of “Come home to a living fire” 😀 😀 Remember those UK advertisements in the 80’s ?

  11. Thanks, but all the credit goes to Albert who came through in a topic doldrum that my head is still drifting around in. I’ve been mostly following humanities topics and doing an internal rumination about them… with an occasional observation in connection with the real world.

    Today, while seeking a replacement mouse, I stopped by the most convenient location that carried computer mice and breaded okra. There, I came to the realization that the phenotype for the paleolithic Venus of Willendorf is very much alive and well, and probably roaming the ailses of your local Walmart. 28,000 years ago they probably would have been worshiped as goddesses incarnate.

  12. I am sorry had to post and go, one of the pups was running around the hallway, bugger..
    It was mag. 4.2, dept.2km about 5km fro Ash, just before 3 am, that would have been felt, hope their is not to much damage, the ground under our feet is regarded as stable, not really as we all know, but mostly forget unless it happens in our backjard.

  13. I know VolcanoDiscovery isn’t the most reliable source of info, but according to them there has been some seismic unrest at Chaiten and apparently the alert level has been raised to yellow.

    Just thought id mention it. 🙂

  14. Waiting for comments about linking El Nino to strange earthquakes in the UK………:D 😀
    I wonder about the channel tunnel at times like these!
    Most larger quakes in the UK have epicentres in the English Channel or southern North sea.

    As regards El Nino the UK Met office has posted a news report about it…this means we have something to blame for the UK weather this year rather than the weather people 😀 😀

    (PS. Yes! I do know that El Nino wouldn’t affect fault movements!)

    • The El Nino cannot be blamed for the coming English summer: it is predicted to be weak until at least August. We will have to find another excuse if the summer turns out as usual. Katla perhaps, if we can get it to erupt by June?

      • I’ve been jumping up and down as hard as I can….

        While chatting with the nutritionist, I mentioned the beach closings in Southern California and how it must be refreshing to be able to have a beach closed for something other that fecal/bacteria contamination drifting north from Tijuana. Then she noted that she is from California. So I told her about one of the worlds largest known Asphalt Volcanoes… in the Santa Barbara channel. In return, she told me to stay away from starchy foods.

      • Perhaps Leslie could give her a prod when she visits Iceland next month 😀 It’s nearly Midsummer’s day. Only a few weeks away and it’s more like Autumn here. The real reason it’s so cold and grey up here in Northern England is because I sorted out my summer tops and T shirts and vacuum bagged my winter woollies Since then it’s been one day sunny one day cold, grey and very British maybe if I unpacked my Christmas fleecy jumper then things may improve. 😀

  15. Holy Cannoli Bat Twerp!

    There is a competing movie out this year to San Andreas, called San Andreas Quake. I’ve already done a little bit of deconstruction on the first one. But from the IMDB listing for the 2nd one: “When a discredited L.A. Seismologist warns of an impending 12.7 earthquake, no one takes her seriously.”

    Well, at least they stated what sort of quake they are talking about. From the Wells-Coppersmith formulas, a Mag 12.7 in a strike-slip setting, give you 128824.96 meters AVERAGE displacement. That’s right, 128 km. (average). The G-force acceleration of the ground at the epicenter (NOTE: This is a very dubious calculation) is about 1582091.5 %g. (It’s calculated off of MMI levels that I don’t think actually exist. MMI- XXII? WTF?) and MMI-X or higher shaking out to around 920 km from the epicenter.

    Just to let you know. This is phenomenally larger than any actual quake ever recorded, and typically only shows up in the results from asteroid impact scenarios.

    In this case, I really think Hollyweird has gone full on stupid in their scenario.

    The gist of the movie is that some teaching Geology professor has come up with a tablet app that yeids about 5 to 30 minutes of warning before a quake hits. Through out the movie it has always been a fraction of a magnitude under the actual quake, and she and one of her students are trying to race downtown to save her daughter, dealing with distraught citizens and a pissed off rampaging Hippo along the way. (I guess from the zoo) From what I have seen, their CGI budget was a bit anemic. Oh, and her work cohort over at at the airport lost his helo when a Cessna crashed into it about 50 feet from where he was standing… so he’s stranded there. And amazingly enough, not singed at all.

    • Okay… this thing is a dog.

      The geology professor arrives with her student at the hotel where her daughter works. Through some act of heroism she distracts the manager in the lobby holding everybody at gun-point, including the two military types carrying what appears to be air-soft M-16s, her student tackles the guy and the military types truck the manager guy out to some arrested peoples area. The geologist and group head for the roof, {yeah, figure that one out} leaving an elderly guy and his wife (who won’t leave him even though they’ve been told all hell is fixing to break loose.) On an upper floor, the quake starts to hit and the hero student guy slides on his belly across a horizontal floor and falls partway out the window. The daughter (being rescued) goes to help and in turn, falls to a clutching the first guy to keep from falling position, and her creepy co worker with the abnormally large mouth (and huge teeth does this.)

      Scratch that, creepy coworker just took a dive out the window.

    • And somehow the geology prof’s coworker scored a UH-1 (AB-212?) to make up for his lost helo… which explains why they headed for the roof, so they could be rescued as the building collapsed out from underneath them…

      At least the CGI is better than the building collapses that we invoked in the game 7 Days to Die. (but not much better)

      They really should have hired the guys that did 405: The movie.

    • Hey, check it out. The first I’ve seen of this video. It sort of documents what Ivan did here in Pensacola at the beginning of it.

      Yeah, it’s kind of an advert, but I use the new bridge almost every day and am quite happy with not being stuck in traffic anymore. One of the follow-on projects of Florida DOT is to “Three lane” this section of I-10 all the way to Avalon Blvd and to erect concrete sound baffles to cut down on highway noise in the nearby neighborhoods.

  16. A tremorish pulse at Grimsvotn, indicating movement of fluids, which in this case. is pretty much magma. 🙂

    • I use a different chart. It is the one that counts the days between the end of the last eruption and the beginning of the next eruption.

      • I use all charts. 🙂
        And chill, I am not forecasting an eruption, but just trying to show a possible short tremor pulse due to magma movement under the volcano, very similar to what we sometimes see at Hekla also, tho lately quite rarely.
        And yes I respect that chart of yours, tho I do think its a little bit overrated. 😀

  17. I’ve started reading “Island on Fire” (about Laki). While reading the author’s chapter about the discovery of plate movements and ocean floor spreading I was reminded of something I’ve pondered recently based on the “volcano season” controversy. When the Earth changes, is it generally repeated small changes over short intervals or large changes with long intervals between? … The magnetic striping shows movements in chunks of a few hundred thousand years, right? Or is that a simplification? Can one tell progression of the ocean floor in significantly smaller chunks of time (either through magnetic mapping or carbon dating from the core samples)? There must be a cyclicality to the build-up of hardened (magma? lava?) at the ridges and the force needed to push the plates apart a bit more to open a clearer path out. … I have the image of one of those carnival-type games called a “coin pusher”.

    You can have lots of input with no output, or little output, but very rarely (I can’t find any stats on how often), a little input can trigger a lot of output.
    Under that model, the large changes with long intervals between makes sense. … I like pondering and trying to figure things out on my own — then asking people who have studied whether I’m on the right track.

    • The only real thing I can add to this mix, is that the predominant driving force behind plate movement is believed to be “slab pull” rather than “slab push.”

      This is the reason that the Cascadia subduction zone doesn’t generate as much melt to drive the Cascades as does the subduction zone over by Kamchatka. The Farallon detached about 20 myr ago and doesn’t contribute to dragging the plate down as fast since only the fragments left over from it that make up the Juan de Fuca, The Gorda, and Explorer microplates can do the pulling. Dr. Klemetti covered this in a recent article of his: “Why Have Volcanoes in the Cascades Been So Quiet Lately?” And, since he has been known to disappear for extended periods into the Cascade range actually studying those critters, I think he is a pretty good authority on the subject.

    • Continental motion is smooth. There are minor fluctuations associated with the biggest earthquakes, but overall it is constant movement. Continents are heavy and have a lot of inertia! The striping actually shows constant motion – the stripes come from occasional reversal of the magnetic field, and are a bit like the stripes on a mowed lawn. It doesn’t show that the lawn mover moved in spurts. The motion of a station in south Africa is shown below. It is moving with the rest of Africa at 2cm/yr or so, and is almost completely constant apart from a brief and temporary slight change in direction in 2010, probably with a local origin. The three panel show east-west, north-south and up-down motion. Iceland does show sudden motion at the rift, as last year, but this is only seen close to the rift. Over large distances the movement becomes very uniform.

    • 😀 If I had told my husband I had finally came to the conclusion that I’m nuts, he’d say ‘what took ya so long’. 🙂

    • Well, I know it’s true now. While returning from helping my step-son move a washer and dryer, I saw something while driving through the bottom land along the Escambia river that I have never seen in my life. A lizard running across the road. Thats right, a little anolis carolinensis, jacked up as high as it’s little legs would get it, giving it all it could to get across the road. And the amazing part? He made it. I eased over a few inches to give him some clearance since he put forth such a valiant effort.

      Later today I saw another oddity. A Plastic tray of cheese nachos sitting in the turning lane at a nearby traffic light, fork stuck in them and pointed vertically like some midget antenna. My guess is that they were so bad that the driver just opened the door and set them there. That also means that they were a special kind of litterbug who think the entire world revolves around them. That’s okay, karma will get ya. 😀

  18. In keeping with my “Azalean Overlords” post, a tidbit…

    Although volcanic activity on Mt. Hakone, on the border of Kanagawa and Shizuoka prefectures, has resulted in an eruption alert, tourists flocked to the area on the weekend, apparently drawn partly by fine weather and partly by blooming azaleas.

    Access to Owakudani, the center of the volcanic activity, has been restricted.

    But thanks to successful countermeasures against the negative impact caused by fears among would-be visitors — mainly by disseminating the information that only a part of the area is off-limits — Mt. Hakone was crowded with tourists on Sunday.


    And a factoid from my other post, Azaleas love an acidic soil. And a quick note about that “Reader Participation Invitational.” If you express an interest in it, make a short note here on the Cafe and I will send you an email. The return address (me) will be perfectly fine for submitting your material. As you can see from some of the past posts, our readers tend to generate some great reading material. (witness the main ariticle for this thread.)

  19. According to VolcanoDiscovery, Wolf volcano in the galapagos islands may have just had a very large eruption. Starting this morning at 08:04 UTC, Washington Volcanic Ash Advisory Center (VAAC) has issued several alerts of ash plumes reaching up to 35-50,000 ft from the volcano, based on GOES-EAST satellite imagery.

  20. Ahimsa!
    I have been bludgeoned around the head by Henrik, Lughduniense, Sissel, Nick and the cat with four tails to get out of my own wazoo.
    I have lost your real email Lurking. Could you readmin us so we can do something with the Wolf thingamabob?
    And just to prove I am me… Lawndart Seismos rule.

    • At F’ing last! 😀

      Long live the King! 😀

      ontopic: Not sure why, but the Wolf volcano oddly reminds me of Hekla.

    • I think we already established that the Lawndarts would be a a bit dangerous to deploy in a populated area. 😀 . I like the simplicity of deployment, but strapped to a brick provides acceptable coupling.

      BTW, I now hae empirical evidence that Nordic countries go bat-shit nuts on midsomer. The Åland Islands conception rate during June is 118.7% of the running monthly average.

      • Winston Wolfe was a character from Quentin Tarantino’s Pulp Fiction. His specialty and function were to take sticky situations and clean up the mess/destroy evidence of a crime/murder. Though the movie was a gore fest, the Wolfe character was quite funny as he was directing the actions of the characters of Vincint Vega, Jules Winnfield, and Jimmie.

  21. We will Wolf something up. Waiting for a MODIS or something from Peter Webley.

    Good to be back. Stellar work from GL holding up the fort!

      • Well, the really annoying appointment with the Nutritionist did have a good result. Now by wife has discovered that she is adept at frying catfish. Prior to that appointment, she wouldn’t even attempt to do that. Even going as far as turning up her nose at any fish that I fried. But, now that an “expert” has mentioned the benefits of fish, she gave it a try. On the plus side, I am a great fan of catfish. On the down side, the place where I used to fish for Flounder has been taken over by the local whackos and turned into an oyster bed and artificial salt marsh. Before that, you could wade out into the cove and cast around for Flounder.

  22. For Diana: Conolophus marthae(pink land iguana) – had been found by park rangers [At Wolf] in 1986 and has been studied by scientists since 2000. Scientists are unsure where the species developed as it is believed to have separated from the other land iguana of Galapagos prior to Wolf volcano or Isabela Island having formed.

    And something for everybody: If I remember correctly, according to Global Tectonics 3rd ed., the plate fragment that the Galapagos rides around on slowly rotates as it is driven by the motions of the larger plates that it is wedged between.

    • Oh My! ..and there’s me with a real problem…I dislike the fashion for PINK… in all things girlie. I so feel for the male of the species….No wonder it’s only found on Isabella Island…I mean…how does a warmed up male Iguana cope with being PINK and coming from an island that has such a feminine name. No wonder they have been laying low all these years!!

    • … well. the “Pink” Flamingos that are the unofficial official mascot of Florida, become pink due to the carotene in their diet of crustaceans (brine shrimp) and algae.

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