Santorini – End of Civilisation

Santorini – The most beautifull harbour to enter in sunset on Earth. Sunup is equally stunning. Nea Kameni in the middle.

Short background

Few volcanoes have such an ominous reputation as the Island volcano of Santorini. And it is in one way a justified reputation; after all it is one of the few volcanoes that have been the end of the civilization as we knew it when it happened.

Today’s island group of Santorini consists of a large caldera ring constructed of no less than six (6!) independent calderas constructed during massive caldera forming explosive eruptions. The largest island is to the east and is named Thera, than follows clockwise Aspronisi (small) and Therasia. Inside of this large caldera basin lays the two islands of Nea Kameni and the adjacent smaller Palea Kameni.

Against normal belief the islands are of a non volcanic origin. Instead they started as a mainly limestone based island as the sea bottom was pushed up by the same powers that made the Alps into the rather craggy mountain chain that much later gave name to the Alpinist tribe.

Later the Hellenic Trench Subduction Zone got active as the African Plate slammed into Europe and got pushed down under Europe. That little event started quite a bit of volcanic activity. Today Santorini, together with its neighbor Colombo Reef, share the distinction of being active Greek volcanoes with Kos, Methana, Milos, Nisyros and Yali.

Image by Nasa.

Pre 1610BC caldera formations

The first mega cycle of caldera formations happened about 600 000 years ago. It was most likely the largest eruption at Santorini and is still responsible for the largest of the calderas. The next caldera formation came 360 000 years ago and had a different magmatic combination than the previous. It was highly siliceous and created highly evolved magmas through crystallization, this type of siliceous magmas are still the norm. 180 000 years ago it was then time for the southern caldera to form, then came the Skaros Caldera 70 000 years ago. After that came the Cape Riva Caldera about 21 000 years ago, the youngest caldera is of course the 3 600 year old Minoan Eruption Caldera.

Caldera formation process of Santorini

During a mega-cycle Santorini has series of cycles with smaller eruptions that build up a volcanic edifice. These eruptions are normally unimposing events ranging between VEI-2 and VEI-3 judging from historical records and excavations. But it is probably not impossible for a VEI-4s happening during a cycle. During the cycle the magma chamber evolves and becomes continuously larger with time. This gives more time for crystallization to happen to the cilicic magmas which gives more and more evolved magmas as the cycle continues. So any VEI-4 or larger would most likely come late in the cycle. The current cycle between caldera formations started in 187BC with an island forming event.

The different Caldera forming events have given differently coloured layers. The most recent is whitish.

1610BC Caldera formation

Few eruptions have such a reputation as the 1610BC Minoan Eruption. It has been given the blame of the biblical story of Noah, the sinking of Atlantis, the disappearance of the language of Linear-A, and of course the fall of civilization as that time knew it. It was not only the Minoan culture at Crete that started to dwindle, also the Hittite, Babylonian and Egyptian cultures showed a rather marked decline during the time after this. The only people that oddly enough seemed to benefited where the 12 tribes of pre-Israelites that formed Israel in the ensuing power vacuum. Jolly good that did for them, as soon as the Hittites, Babylonians and Egyptians got back on their feet they made short order of Israel. Sense moral is that no volcano may ever protect you from biblical revenge.

Technically the 1610BC event was a VEI-7. It is believed to have begun as a VEI-6 ultra-plinian eruption, with a massive effusive component that caused the by then very large magma chamber to subside enough for the ocean to fall into the half empty chamber. When we are talking about the magma chamber of 1610BC we should remember that it does not exist any longer. The size of that chamber was in the order of a 1 000 cubic kilometers or more judging from the erupted material, and the eruptive standard value of 5 to 10 percent of the magma being ejected. Today’s chamber is probably around 1 to 5 cubic kilometers.

As the water came into contact with the open magma chamber a violent Ultra-plinian VEI-7 event took place. It caused wide spread tsunamis and heavy weather affecting atmospheric conditions.

Santorinis normal eruptions

During the period from 187BC and up to 1950 Santorini have had 10 sub-aerial eruptions. And at least four separate island forming events. Two islands have later been subsumed by Nea Kameni. Neither of these eruptions has been spectacular in any sense of the word. In addition there has probably been sub-aquatic eruptions inside the caldera ring, but those has either not been written down, or was too deep to make a surface impact. The big exception is of course the Colombo Reef (6,5km NE of Thera) eruption of 1650AD which formed an ephemeral island.

Other than being small in scale, the eruptions are normally prolonged in time. Eruptions lasting between one and two years are not uncommon.

Photographer unknown, postcard that I bought the first time I sailed to Santorini.

Signs of an upcoming eruption

Up until a couple of years ago Santorini was subsidizing, this together with cyclic swarms of earthquakes over at Colombo Reef lead researchers to believe that an eruption was up and coming at that location, and not at Santorini.

About a year ago a marked inflation started at Nea Kameni together with increase in CO2, SO2 and the Santorini marker gas of Radon. Together with an increase in seismic activity lead to the scientists starting to keep a bit of a closer watch on the volcano.

Lately we have seen quite a few more signs of an upcoming eruption. We have now had swarms of earthquakes inside the caldera at the right depth, microseismics that remind of popping giant popcorn in a spectral analysis, and of course harmonic tremoring lasting from hours to days.

We should though know that this has happened before in volcanoes of this type without anything happening. But let us say that the likelihood of an eruption happening has risen quite a lot.

What will an eruption look like?

Most likely an eruption now would be a dome forming event at Nea Kameni. The beginning will be explosive, and then trending to effusive as lavas are extruded. Most likely it will be a VEI-2 event, but a VEI-3 is not out of the question. The eruptive period is hard to predict, it could be anything from one month to four years. There is really no saying which. And historical records do not give much help; it is equally possible that the eruption will be short as long. Playing hard and fast with statistics here would only give silly results due to lack of substantiating occurrences.

Are you starting to get the thing with the Santorini sun yet? Nea Kameni out in the bay.

One thing is for sure, there will be no end of civilization as we know it, this time around.

CARL

A special thanks to Summer who fixed the code in the last post, and told me how to not bungle it up again.

Update

The earthquakes that some believe to be at Santorini are not really at Santorini, they are located 12 to 25 kilometres south to south west of Santorini. They are located at a faultline that is cause by the subduction of the African plate under the European plate. The same process that help sprout new members of the alpinist tribe.

It is quite possible that the tremoring noticed is also related to this, about that we will hav to wait and see.

Image by EMSC-CSEM. As you can see this quake is 12km SSW of Santorini. This quake was one of the more northern in the Swarm. It is located in a fracture zone between two faultlines.

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671 thoughts on “Santorini – End of Civilisation

  1. Should not the powers that be be taking more interest now especially as the quakes seem to be consistent and shallow .

    The 3.4 earlier was shallow surely now some alarm bells should be ringing ?????

    • If you count the smaller quakes, the total number for February is now up to 24. But ¡no te preocupes!, because Avcan says the seismic activity level is “normal”. 🙂

      • Normal to compared to what?
        It is assuredly more then normal levels before the pre-eruption phase. El Hierro was pretty much aseismic before that.

    • Good morning Judith, I think they need to watch Bob not Banana’s. I wonder what Bob is going to look like when the light comes up.

  2. Good Morning Hattie

    I think the whole load of them the so called experts in El Hierro are just a bunch of banana’s.

    • Good morning Judith, the eruption cam is white out right now , and the panoramic cam is a bit hard to see, but it looks like a fairly big stain I think.

  3. Rescued from the page roll. Same plot.

    GeoLurking says:
    February 4, 2012 at 06:36

    Time vs Depth vs Mag.

    —————–
    Carlos noted:

    “It would very intersting if a graphic of tremor could be put at the top of your work, to see in real time how is the evolution of the tremor depending of the plots you marked and how many retarded is tremor respect EQ´s energy”

    That’s not a bad idea. I may have to fight the dimensions of the two plots (one of which would be a composite) but it is doable.

    Good idea.

    • The issue is going to be the length of time. My plot is about 34 days long… that’s a lot of images to string together for the tremor plot and get aligned properly.

      I may have to do that on shorter time series if something significant pops up.

    • Thans for your work…
      But do not hurry, if you see interesting it you can do it another day. For you now are 2.30 am

  4. I think with 10-15 days series would be good enouhg to see the delayed tremor respect EQ´s energy..
    I dont know if with a 15 days period it would be good enough to adapt the tremor plots.
    I think the energy transer wont go farer than around 10 days for deeper Eq´s and no more than 4-5 days for shallow EQ´s.

  5. Good Morning all. So much to catch up on. Bob’s second name should be Lazarus! José Luis Barrera Morate..What a fine article.he has written. It sums up what we have all observed and speculated upon and that we are all wondering…… what comes next!
    Carl has found a “New” Volcano in Iceland.I am so pleased that my thoughts about Sauber tremors are not just an old lady’s musings. I still watch and wait with interest around the foothills of Hekla.
    A sudden drop in strain at this time is odd maybe.

    very cold again and a beautiful red sunrise. “Red Sky in the morning , the Shepherd’s warning”This is an old saying that is remarkably true…..Today therefore I go to the supermarket early in case the forecast snow drops heavily on us!

    Pooper the Pigeon continues to survive. He is still not eating very much and this worries me but he seems brighter. Birds are notoriously good at looking fit and well before they drop dead!

    • Morning Diana, I hope old popper is as tenacious as Bob, if he is he will make it. Good luck with the weather. I remember as a child snow brings England to a standstill pretty quick.

      • Good Evening to you Hattie 🙂
        Yup! Snow here is a huge Joke. The best quote was from the Railway official who explained…” Trains have stopped running as there is the wrong sort of snow on the tracks” 😀 We can cope with war and pestilence but are brought to our knees by half a centimetre of snow!

    • Good morning Diana and All.
      Glad to hear Pooper is ding good. It is rather cold here too, not sure if we ll get snow, might be better for the plants if they had a snow-cover cause atm we have none.
      Wasn´t the last small earthquake right under Carls new volcano? If yes, he might be happy when he wakes up.

        • Fine with me, although i am not sure if our Carl would like it if Minicarl would start erupting. ( And we all hope Carl wont start erupting when barbaqueing his hat next summer) But he suggested a name Sæturvatnbunga ( Had to look it up because i have not the slightest idea what it means.) And Ursula found out it already has a name… Illavatn ( or so) Bad Water. I dont know if Carl wants his name connected with bad water.
          Wasn´t Bobs original name Pancho?

          • I am not sure Birgit, the name Pancho seems familiar. And what ever name is chosen to be used for this new volcano is sure fine by me.( Smiley face)

          • Bob was Bob before they invented Pancho. It is always a question of being first. 🙂

            I think in this case since it allready had a name we will go with that one.
            Illavatn is a rather good name for a volcano I think.

  6. Just posted on Avcan Fb

    Last night trembled again strong at least I felt it in the mocanal
    See Translation

    Again this Mocanal area is being talked about it still is in the back of my mind this was a focal point for something a while ago?

      • Thanks Judith for the map. Mocanal was mention quite a while ago, but I really can’t remember the context now. Also up on the north coast in the early days, Bob vented some gas from the rocks along the coast.

        • There is a guy posting at AVCAN (Victor something) who lives in Mocanal and reports tremors, sounds, smells, etc. every time something happens.

          • Sounds kind of digital, either he is imagining things, or he will get his ass blown off one of these days. It is the word “smells” that would make me consider having my running shoes on 24/7.

      • Judith, I found the original Spanish on the Avcan FB site:
        El sismo de 3.4 MBlg ha debido ser por el agotamiento… I would translate:
        “The 3.4 magnitude earthquake must have been because of exhaustion.” In other words, I think she is saying that the volcano has exhausted (or depleted) itself.

        • Hum, I am no expert and that’s for sure, but I don’t think Bob has depleted himself. if you look at the other stations the red at the bottom of the charts is getting stronger.

          • Well, I didn’t say it, nor do I think it is necessarily true, but that is what “C. Lopez” believes or wants to believe. I suppose that earthquake could have been one of Bob’s feeder tubes collapsing, assuming there are more than one. With the harmonic tremor still going however, I don’t think s/he’s a goner yet.

          • depletion = emptying of magma chamber. There is not sign on the GPS of that having happened. It rather looks to be a full blown Pressure Equilibrium Eruption (PEE).

        • If so, then somebody may want to tell Bob…

          1124878 04/02/2012 04:43:00 27.6547 -18.0328 14 1.6 4 SW EL PINAR.IHI
          1124888 04/02/2012 05:43:38 27.6969 -18.0621 13 1.3 4 W EL PINAR.IHI
          1124889 04/02/2012 06:35:17 27.6567 -18.0428 14 1.5 4 SW EL PINAR.IHI

          All after the 3.4.

  7. Warning… OT.

    I don’t know… I must be weird. No normal person would sit around on a Friday night and do the sort of shit that I do with data.

    The CERES satellite is now collecting data. I ran across some of it’s first imagery over at WUWT in an article. It presented two images, the amount of energy reflected from the tops of the clouds for the whole globe… and the amount of energy blocked by clouds (coming from the Earth)

    Well, an enterprising idiot like myself could derive some meaning from that…

    Digitizing the out-bound energy image, I was able to export it and then average the cells for all longitudes at a given latitude, then plot the results. Finding the integral (with the program, I’m not that masochistic) I was able to determine the total of all of that, and then slew the curve so that it represented the percentage of energy loss at specific latitudes.

    Tossing in some reference lines… (Tropic of Cancer/Capricorn, the Arctic/Antarctic circle), it made a very enlightening graph.

    It seems that Earth looses most of it’s surface energy from the Southern Hemisphere…. and clouds block most of the outbound energy in the tropics. The Northern Hemisphere comes in at a lower output. In all likelihood, this has to do with the extent of land vs water.

    Anyway… enjoy the plot. (I’m not an atmospheric physicist either, but your child or student may find the plot handy)

    • I like it! I especially like that it is rather symmetrical, somehow that makes it seem like the planet is somehow in balance. Or could it be symmetrically out of balance? Oh, no! 😮

    • You have probably in your navy days (almost wrote maritime there) been hit by the answer to your question about why the southern half emits heat better. I will write the answer more for the rest of the crowd.

      In the southern hemisphere you have a belt of high wind speeds carrying wast ancient storms. It has three names, Roaring Forties, Shouting Fifties and Screaming Sixties. The high windspeed works as an enormous fan sucking hot air down, cooling it, and containing it so that it can dissipate very effectively. It works as a barries against the Antarctic. So you have a low temperature, high energy area that is either transforming heat into wind, or dissipating it.
      The reason for it existing at all is that there is no land really it can loose power against.
      This area is probably more important for the short term weather on the globe, then the Gulf Stream.

  8. Avcan FB Copied

    A 3.4 near the coast between Cala Pinar and la Restinga, after having many seismic peace, from the beginning of December, since few days more restless estasba and think it is relaunched, has today been confirmed. If someone it has felt, remember to fill in the questionnaire macrosismico of IGN, is very important… so much that it is the only thing that the authorities give importance of truth… felt earthquakes.

    1124870 04/02/2012 04: 40: 28 27.6508 – 18.0230 16.4 3.4 SW PINE.IHI iron

    • *sigh…

      I really hope that 0.59 hz signal is just an artifact. It’s starting to show in EFAM and CFUE quite well.

        • 0,59Hz signal is believed to be a signal from the deep feeder tube that is bringing up more magma to El Hierro. The sound of the hotspot mantleplume.
          And since it has been active again during the few last days, and increasing in strength, it might mean that Bob is going to get more active, or that the system might get to pressurized for Bob to be sufficient as a pressure relief valve. I think Bob is enough though.

    • Did you notice that every day around 0h50 there are 2 lines on the PSd ?
      Wonder what that could be. They are ther every day at approx the same time.

      Any idea ?

  9. http://www.avcan.org/sismica/graficas/G784.jpg?t=1328299945

    In the graph of evolution of the seismic energy released from the first of December, beginning to see a change and after another day 25 of January of 2012 2.8, the slope of the periods with low seismicity where is the release of energy and which was constant since the beginning of December, has changed and has become more steepIE… more energy is released from the 25th day, seems not very noticeable… But today with the quake of 2.7 and then 2.4, I made the chart and I’ve seen, in fact indicaria a first step in a revival, the truth is that something is has been revived now… must see if continuing the trend of slightly higher or returns to relax and is only an isolated spike. (Henry)

  10. Well getting real tired here so time for bed. Hope you all have a wonderful day, and for Denise and Lurking hope you have a good night.

  11. Hi Renato and all, I’m sure I saw one incandescent restingolita in the night before going to bed, unfortunately not as I was capturing. It gave a very bright, emerald green light for 1-2 seconds.

  12. The stain seems to have moved westwards during the night (new mouth?). The cams do not look that far west so we cannot see the whole stain. And the movistar panorama cam is almost completely white so please, operator, if you see this, take a look at the settings!

  13. I wish we had an aerial shot of the stain today. It looks to be in two parts but it’s so hard to tell if that’s just because of the currents in the ocean or if there is more than one mouth.

    • An aerial shot would be good. It is difficult to tell what is volcano-related ativity and what is weather-related activity. There are more waves from both; but hard to tell from the shore how they are interacting, except that the weather-related waves are catching on somethings (updward flow of hotter water from above Bob, I guess).

  14. Seen by the webcams from 10:40:

    It is in fact very difficult to see how big the stain is. On the panorama cam it goes as far as we can see to the west, on the eruption cam it looks smaller.

  15. There is a much bigger concern that Santorini, for those who worry about end of the civilization:
    Greedy capitalists (politicians and bankers).

    • Santorini is so far down my list of things that can bring a halt to our civilization. And to be honest, I do not really think that anything could do more than put a bit of a halt to it, at least without killing us all. And that is rather not likely that any volcano could, not even a trap-formation event.

  16. With all this wind on the sea at El Hierro, creating a visible horizontal wave movement, it is easier to stop Bob’s activity as it is more “vertical” in nature. That creates a difference in wave behaviour that makes a noticeable contrast.

  17. Slightly OT: I think it was Alan C that recommended getting “The Earth’s Dynamic Systems” by W. Kenneth Hamblin for those of us who are geologically challenged. Then someone said it was very expensive (sorry, I can’t remember who it was), but the good news is that I’ve just got a copy which only cost me GBP 2.95 including postage – from eBay.

    • Thank you very much Talla. I have ordered one off Ebay but it will be delivered to my daughter’s address in England so I won’t get it until I visit in April.Thanks again, I never thought of Ebay when I was searching. 🙂

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