A Tube´s tale: Part 2 – strange creatures and the human touch

Monte Corona from the northwest.

When it formed around 21,000 years ago the Corona tube came to an end when the lava flow reached the sea. In the subsequent post-glacial period the vast ice-caps retreated, raising the levels of the world’s oceans.

As sea levels rose so the outer reaches of the tunnel became inundated. Sea water penetrated into the tunnel as far as an area known as the Cueva de los Lagos (‘cave of the lakes’), around 600 metres inland from the current coastline. During the reshaping of the Jameos del Agua that took place in the 1960s/70s the tunnel was artificially cut off from the sea. Water that remains in the caves upstream has collected by the seepage of rainwater.

Tunnel of Atlantis

A tunnel leading from the jameo closest to the sea provides access to the underwater portion of the tunnel. The 1618 metres of the tube that is now under the sea is known as the Túnel de la Atlántida (‘Tunnel of Atlantis’), and is the longest underwater volcanic tube known. It was not until 1988 that cave-divers completed its exploration. Features of this section are the Montaña de Arena, an 11-metre high mound of sand that has accumulated underneath a small hole in the roof of the tunnel, and the Lago Escondido, an air chamber that can only be reached through the submerged portion.

The Túnel de la Atlántida has created distinct anchialine biotopes where strange creatures have made their home. Shut off from virtually all light apart from a small amount in the Jameos del Agua lagoon, these animals are blind and lack any pigmentation. Seventy-seven species have been discovered in the anchialine sections of the cave, including the galatheid crab (Munidopsis polymorpha) that has become the symbol of the Jameos del Agua. While this tiny white creature is the public ‘face’ of the caves, it is two recently discovered species of remipede (Speleonectes ondinae and atlantida) that are scientifically the most noteworthy, as they had previously not been found on the eastern coasts of the Atlantic.

Galatheid crabs thrive in the partly lit lagoon at Jameos del Agua. The blind creatures grow to about 2 cm in length. This poor chap appears to have lost a leg

Humans and the tube

With the jameos providing ready access to the tube, humans have used sections of the tunnel for many centuries. Its constant temperature of 19°C made it a natural place for food storage, and it became an important place of refuge.

During the 16th and 17th centuries Lanzarote was repeatedly attacked by pirates and slave-traders, mostly from North Africa, but also from northern Europe. Such attacks ranged from small raids to full-scale invasions. In 1617 the English adventurer Sir Walter Raleigh laid waste to the main port at Arrecife, one of his last actions before being beheaded on his return to England as an appeasement to Spain. A year later a 5,000-strong army of Berber pirates led by Solimán pillaged the island with much bloodshed.

A group of tourists prepares to descend into the Cueva de los Verdes. In times past islanders used the caves to shelter from pirate attacks that primarily came from England, France and North Africa

During these raids – and others – the jameos of the Corona tube became a natural hiding place for the island’s population, in particular a system of caves known as Cueva de los Verdes. Such use of the caves is first recorded in the 1590 writings of an Italian engineer, Leonardo Torrini, who noted that the caves also provided an underground route to the sea should the need arise to escape by boat.

Tourist attractions

Despite its name, the ‘Cave of the Greens’ is not green at all, being named instead after the Verde family that owned the land. During the more peaceful times (at least for the island) of the 19th Century the cave became a popular destination for wealthy European travellers visiting the Canaries. In the early 1960s, as Lanzarote began to grow in popularity as a package holiday destination, the local authorities decided to develop the Cueva de los Verdes as the island’s first major tourist attraction, which opened in February 1964.

While cavers had opened up more than 4 km of the tube, around 1 km was prepared for casual visitors, featuring up to three levels in one section. Walkways and atmospheric lighting were devised and installed by architect Jesús Soto, a close collaborator of the renowned Lanzaroteño artist Cesar Manrique. Incidentally, Soto also schemed the Ruta de los Volcanes, the road that now carries the tour buses through Timanfaya national park.

Although there are some still ponds in the cave system, it is largely dry. Most of us know limestone caves, formed by water erosion. As the Cueva de los Verdes was formed by an entirely different process there are none of the familiar stalactites and stalagmites. However, in many places there are small ‘lavacicles’ formed by the solidification of lava that has spattered on to, and dripped from, the roof of the tube. In some parts of the tube they form pointed rows known as ‘diente de tiburón’ – ‘shark’s teeth’.

Lava spattered on to the roof of the tube forms ‘lavacicles’

Throughout the tube there has been considerable collapse of roof material, there are many areas where the original smooth tube wall is obvious, with a rougher, flat floor where the lava stream has solidified in situ.

This view shows a flat section of solidified lava stream where it butts up to the smooth sidewall of the tube

Manrique’s masterpiece

Downstream of the Cueva de los Verdes, shortly before the tube dips under the sea, are the Jameos del Agua. Along with the Timanfaya volcanoes, this location has become the island’s most popular visitor attraction. Two jameos  – Chico and Grande – are linked by a lagoon partially lit by a small opening in the chamber roof. Here the famous white crabs can be seen in a part-natural, part-sculpted setting created by the vision of Cesar Manrique.

Soothing oasis in a sweltering, barren lavascape: the pool at Jameos del Agua looks cool enough to satisfy the hottest polar bear

In the Jameo Grande a typically ‘Manrique-esque’ lava garden has been created, with a serene blue-water pool. Although it is Manrique who is credited with the concept of Jameos del Agua, apparently it was Soto who oversaw much of the detailed design and the day-to-day work. The first section was opened in 1966, and further areas were opened up progressively until 1977.

Beyond the Jameo Grande, in the tube itself, is a subterranean auditorium used for concerts (a smaller auditorium is also to be found in Cueva de los Verdes). Above the jameos is a visitor centre complex, including the highly recommended ‘Casa de los Volcanos’, a volcanological research and educational establishment.

It may not quite be a VolcanoCafé, but this LavatubeCafé at Jameos del Agua could be the next best thing


Overground photos by author; underground photos by ‘Lill-Viggen’


La Erupción y el tubo volcanico del Volcán Corona – J.C. Carracedo, B. Singer, B. Jicha, H. Guillou, E. Rodriguéz Badiola, J. Meco, F.J. Pérez Torrado, D. Gimeno, S. Socorro, A. Láinez 2003 (in Spanish)

The Corona lave tube, Lanzarote: geology, habitat diversity and biogeography – Horst Wilkens, Thomas M. Iliffe, Pedro Oromí, Alejandro Martínez, Terence N. Tysall, Stefan Koenemann 2009

Good background reading:

The 1730-36 eruption of Lanzarote, Canary Islands: a long, high-magnitude basaltic fissure eruption – J.C. Carracedo, E. Rodriguéz Badiola, V. Soler 1992 (many thanks Schteve!)


181 thoughts on “A Tube´s tale: Part 2 – strange creatures and the human touch

    • Yes, really nice posts UKV! Thanks. Seeing the oceanic crust lava landscapes, one first thinks this is iceland, but no – only similar. Thats not the lava cave in my back yard, but ones thats much much larger. Well, where I grew up there was one small lava-tube in my “back yard”. True! Only 100 metres from the house and was enterable in two places. (one was perfect for children secret hideout, enough space for about five of six!)

  1. Thank you UK Viggen. What a fascinating tourist location. It makes another destination for my dream holidays. Tourists aside the biology is fascinating. It shows just how quickly a volcanic wilderness can be turned into a new habitat. Succession, the natural reintroduction of life into a hostile environment is one of my pet interests. I shall have a look at any papers now about the succession of the marine lava tube and anything else associated with this. This was a joy to read on a Monday morning.

  2. Sleep…. who needs it.

    It’s 2:40 AM, I have two 120 miles calls 60 miles apart… and I have to pick up parts locally for a nearby call… and they don’t open until 9 AM or so. I just got back from hanging out at the ER for 4 1/2 hours while they looked at the stepson’s foot… which has begun to seep plasma from the bruising and dead skin. (yeah, yuck)

    So… how to meet the contractual obligation? Coffee, B-12, and pancakes. I don’t think I’ve pulled a shift like this in 12 years.

    Yee Haw.

    (BTW, that inventory thing? I’m pissed off at it. It seems that for some reason, I have motherboards and mice that are breeding. Every time they send my stock sheet… it has more stuff in it than I reported last time. So, piss away a whole day only to have nothing updated. Yeah.. riiiight. And, I don’t get paid for that time. Hell, I could have put together some really nice graphs with that time… with everything coincided.

    I better stop before I break into a psuedo-philosophical rant…

    • I have worked in the public sector as a teacher, I have worked for a big, USA international company, I have worked for smaller companies and for myself…….The latter option is great but getting the income tends to cause sleepless nights, The other options have steady incomes but the pressure and expectations from contracts and working practices that change frequently cause sleepless nights.
      I now have a miniscule pension (Actually below the UK poverty level) and selling off goods and chattles from 60 years of collecting stuff as well as inheriting father in law’s horde of cardboard boxes of “Junk” helps to pay for essentials. It keeps me busy. I get pleasant boosts to my income. Best of all I get good night’s sleep as I can’t earn any less but I sometimes get more :D. I can’t be made reduntant, I already am. Nobody tells me what to do cos nobody really cares, I have no opposition and no managers.
      Interestingly I cannot claim any financial aid off the state as I got married,rather than living in “Sin” after my divorce.
      Lurking I feel for you, my advice is to retire on little is better than killing yourself before you have time to enjoy time .!!! ((((((((((Lurking. Take care of yourself)))))))))

      • I am retired, at least as far as the military is concerned, but the leash holder says I’m still viable… so I work. My wife is in your situation, no pension because she married me… though she is old enough.

        This is just what I do to make ends meet and pay the @#$@#$ health care premiums that have gone up in the last four years. (about 500%) <- not a typo.

    • We are too old to pull that stuff,Lurk, but you gotta do what you gotta do.
      Actually I’m looking forward to going back in the Airtanker business this summer.
      less stress of being a small business owner…
      Hope your Stepson is ok..

  3. Back on subject. I, like Irpsit, am intrigued by this SIL signal at Dyngjuhals on the North side of Vatnajokull. It is showing remarkable tremoring in all frequencies. I know the wind is fairly strong this morning but not more than normal for this time of year and about the same for the surrounding SILs that do not show this level of tremor. Water flow? I would be pleased for any local knowledge for this.

  4. Thanks Ukviggen, another great post, nice pictures too. Lava tubes such as this have been suggested as bases for human missions to Mars; already there, solid, reasonably feasible to seal/ pressurize and a lot of the ground work already done… Humans have been living in caves of one kind or another through our entire history, there are literally hundreds of caves occupied in the Canaries today.
    I think you were asking for some Brighton tips on tother page… Sussex is a decent uni close to the delights of town in a glorious setting; handy for the Amex Stadium, home of the mighty Seagulls. I imagine it would be a nice place to live in halls; the campus is like a little village but with more than the average number of pubs! Cost of living in Brighton is high even as a student and student houses (like everywhere) tend to be shabby and in the less salubrious parts of town. That said, Brighton is a great town and if you have reasonably deep pockets I would recommend it highly 🙂

    • Thanks Schteve. Daughter liked it a lot, and it made me wish I was 17 again! I grew up not too far away and remember walking through the campus when I was around 5 or so, up into Stanmer Park to see the deer. The campus is about 10 times the size now!

      • Stunning photos – did you take them?
        Enjoy Southampton this week – the Uni is pretty darned good but the social life not in the same league as Brighton!

  5. Today I can feel sulphur smell outside.

    Which is not common, but ocasionally (about once a year) I feel it. I am located in southwest Iceland, 50km west of Hekla.

    But since there is almost no wind, its very difficult to know where it comes from. In past ocasions, sulphur smell has came from Hengill new drillhole,

    Now the wind is very light from the east, so it can´t be Hengill, this could be something else. I have no idea. It can also be a local release of sulphur gas. Anyways its a faint smell, probably very little. Sulphur smell can sometimes be the earliest sign of a volcanic eruption but often it is just degasing.

    • If I remember that right, you live not very far from an active volcanic system, Grímsnes system.

      Also, there are hverir (hot springs) at the southern foot of Búrfell (also the one in Grímsnes), when they grow more active, there can come a more pronounced sulfur smell. So, I wouldn’t think a lot about it, if it is not very strong. 🙂

  6. Thanks for the interesting read ukviggen. Will have to put Lanzarote on my must-visit list. I must admit I have visited the canaries many times when I was younger but was more interested in the colour of the sand then (Fuerteventura being my favourite) but now the volcanology looks more interesting. Thanks !

    • Indeed volcanoes and sunny holidays are a good combination – hence Iceland seems a destination for hardier types!!

      ‘ Anatolia

      Model for Aegean-Anatolian and African plates confrontations, South Aegean Subduction Zone and emergence of back arc volcanic activities.

      Turkey and Greece belong to the Southern Aegean subduction zone off a chain of active and extinct volcanoes, including Santorini and Methana. Only 70 kilometers away from the earthquake swarm the cost Nisyros caldera, which is regarded by some volcanologists as remnants of a super volcano that is still active.

      At the edge of the Caldera is the volcanic island of Yali. The last eruption in the region occurred in 1888 on Nisyros. In the field of earthquake series, there are even no (known) active volcano. So would have to if this is really volcanic swarm, form a new volcano.

      This is likely to be first submarine and perhaps later form a new island. By then it could be dangerous for the residents of the surrounding islands and the Turkish mainland. The worst-case scenario would be a volcanic eruption in the country, but this is unlikely, especially as the epicenter of the most quake off the coast. ‘

      I thought I’d post this quote from the link on the last topic:

      The Aegean is always pretty seismically active and Santorini has quieter and more active days. I guess it is because the pressure is on the region to shrink, under pressure from all sides…..

      • And I agree, Jim, Brighton is a wonderful place to be a student, especially if the arts are your bag. Southampton is primarily a large port but it is surrounded by the most beautiful Hampshire countryside with Winchester not so far away.

        When they were building the M27 it was rumoured that a burial mound with 12 very tall knights buried in it was uncovered and archaeology had a short window of opportunity to study it……

        Not sure if King Arthur was in there with them tho’…. 😉

    • My question is whether this is actually a new volcano, or if it’s actually a very old volcano that has just been recently discovered due to an increase in seismicity. It wouldn’t be the first time a large volcano woke up after a long period of dormancy.

      • If this is indeed an “old” volcano reawakening, it could be bad news. If this is a new volcanic vent forming, it probably wont cause any significant harm until it can first build up an adequate sized magma chamber, form an island, and suffer from potential caldera collapse afterward/

        • It appears so. I just read a reply from Boris Behnke on FB. He told that the station is from the island of Nisyros. That island has ongoing hydrothermal/fumarolic activity (so Nisyros is not exactly dead. He looked at the signals from the from the past weeks and indeed it is growing stronger while nearby stations do not show the same increase, hence does not appear to be weather related.

        • Hi cbus, I don’t think it would be an old volcano.

          A saw a 3D image of the caldera of Kos and subsequent volcanoes show that the only volcanoes that exist in the area are already ones that have reached the surface. In another sense, all the volcanoes thier are ‘old’ because they all come from the same magma source that fulled the old Kos volcano and its caldera forming eruption.

          If a new volcano has formed/ is forming, can I suggest a name for the youngster? How about “Nero” which means smoking in Greek?

          Any other suggestions?

  7. Hi

    Here is the Iceland Vatnajökull area earthquake animation for 2011
    The lower blue grid is the Moho. Elevation is shown and according to the color bar.
    Earthquake animation is displayed time lapse style in the first part of the video.
    I have changed the Rocking chair effect so that the view elevation is always positive (no seing from below as I find it is a trifle confusing)
    In the second part of the video, the color of the dots indicates the age of the earthquake, blue being oldest and red being youngest.
    Elevation data comes from NOAA, earthquake data from IMO via Geolurking

    I have kept the Rocking chair effect for the last part of the video (albeit with a smaller rocking amplitude) instead of keeping elevation at 0.

    Uh is it me eyes or is there some snowflakes falling on my screen ?

      • I anyway would have liked to have a separated “Grímsvötn-Gjálp” picture and another one about Bárðarbunga and Hamarinn perhaps both for the last 2 years, if I may incommode you again. 🙂

        And yes, I would also see here a sill-formed reservoir rathrer shallow locationed under Grímsvötn.

        Some information: http://www.almannavarnir.is/upload/files/Gr%C3%ADmsv%C3%B6tn_almennar%20-uppl%C3%BDsingar.pdf (Text is in Icelandic, but the maps are perhaps interesting).

        BTW: G. Larsen, who is an Icelandic specialist in volcanology, indicates in this text, that the center of the proposed hot spot would not be under Grímsvötn as mostly indicated by others, but under Bárðarbunga and Vónarskarð/Tungnafellsjökull: G. Larsen, e.a.:Holocene volcanic activity at Grímsvötn, Bárdarbunga and Kverkfjöll subglacial centres beneath Vatnajökull, Icland, p.2: http://link.springer.com/article/10.1007%2Fs00445-011-0461-4?LI=true#page-1 This could also be an interesting link @Irpsit if he still likes to analyse tephra layers! 🙂

        • Sorry, should actually be doing something else now, concentration and my English language facilities deteriorating!

          rathrer -> rather, locationed -> located 😳

          • Don’t worry. Mine are shot now also.

            275 miles, no sleep, pumping gas, not happy, bright sun.

            Proprietor comes out with an overly cheerful “Howdy young man!” behind me. I have severely graying thining hair and a mostly gray salt and pepper goatee… not cropped close because it’s my way of compensating for not being able to grow hair after 20 years of military hair cuts. (If you admit it, it’s not a hang up.. right?) So.. I’m thinking to myself, ‘No one is that stupid. It’s not me.’

            Dude walks around the pump and tells me “We’re having a special inside!”

            Me, in the most polite mannerism that I could muster… which borders on growl.

            “I don’t care”

            He seemed to be taken aback by my surly demeanor, and wished me a nice day. I can understand him wishing to try and attract customers… but I was in no mood for it. Had he known me better, he would have realized that I to occasionally use the term “Have a nice day”… but usually when I say it, the meaning is far different and can be gleaned by how I deliver it. A rough approximation is “go [censored] yourself” But… not wishing any more social contact that I had already been forced to endure… I responded “You too.”

            I think I shall go snooze for a bit.

    • In this graph, there seems to be a lot of magma at a few km deep beneath Bardarbunga and in the eastern region of Askja. Also, a nice intrusion into Kverfjoll. And a nice blob of magma just beneath Grimsvotn (probably ready to erupt).

          • What I propose is that Inge supplies the coordinates for the zone to be studied. I’ll do the data trimming then for the last 2 years, so that the zone will be right. I do think that we will not get too many EQ if the zone is right. Remember that (and that’s due to Octave) I cannot handle reasonably more than 2000 EQ, afterwards the calculation time gets too high.

  8. Like Diana has noticed, there is something going one, in the last days, in Vatnajokull. We can see intermitent tremor on and off occuring in Grimsfjall and Dyn (Bardarbunga) stations.

    One of these volcanoes (or Kverfjoll) is the culprit. I don’t know, but the some spot in Vatnajokull seems to be nearing (again) an eruption. This is definitively related to hotspot, which in recent month has caused intrusions all around its center, in its surrounding volcanic systems (Askja, Bardarbunga, Tungnafelljokull, Kverfkoll, Hamarinn and Grimsvotn). Seems like a lottery to guess which one follows next.

    As we learnt in 2011 Grimsvotn eruption, the eruption can start suddently with earthquakes only starting an hour before.

      • I mean: Askja, Bárdarbunga / Hamarinn and Grímsvötn are rather well proven, but what about Kverkfjöll. The system was really very quiet these last years as also before, and it seems that is its habit. (See the a.m. text by G.Larsen, e.a.) And Tungnafellsjökull has not had a lot of quakes neither.

        • Skrokkalda tremor could perhaps indicate something going on at Tungnafellsjökull, but it seems unlikely to me, because Hamarinn has been much “livelier” lately, a.o. producing this glacier run into the reservoir Hágöngulón.

    • There are a couple of tremor charts that make me ask “hm, what causes that?” such as Gilhagi and Skrokkalda.

      PS. IIRC, Grímsvötn (and the entire area) kept quaking months and years, back and forth between Bardarbunga, Grímsvötn, Esjufjöll and Hammarin, before it decided to blow in May. There was also quite a bit of rapid ground deformation, the emphasis being on rapid. IIRC

      • Hi

        As said above, if you or Inge can supply the coordinates it could be interestin that I’ll do some zooming plots. I will probably do not take into account the lower quakes, maybe you can tell up to what depth….
        in the last video I took into account the Moho, but I’m pretty sure we could not take it into account so as to zoom more on the interesting parts.

        • Bárðarbunga: 64°38’27”, 17°31’40”
          Grímsvötn: 64°25’0”, 17°20’0”
          Hamarinn (= Loki-Fögrufjöll): 64°35’15”, 17°47’59”
          Þorðarhyrna (part of Grímsvötn system, central volcano to the south of it): N 64°00.552 W18°15.068 (just got this one)
          Vonarskarð N64°49’43”, V17°36’51

          Acc. to G. Larsen, e.a. the volcanic systems under Vatnajökull often have two central volcanoes, one of them more active (producing mafic magma), the other more quiet, but producing – not least because of its silence – felsic magma (talk about creepiness… ).

        • Re. Gilhagi: I have sometimes been thinking about it (just didn’t dare to talk about it … ehm … 😉 ) . Interestingly, it should be on the place of a high temperature area in the estuary of Jökulsá á Fjöllum http://www.geothermal-energy.org/pdf/IGAstandard/WGC/2000/R0555.PDF. And it is not the wind, compared to: http://www.vegagerdin.is/umferd-og-faerd/faerd-og-astand/faerd-og-vedur/nordurland-eystra/linurit/st059.html (this is on Tjörnes, but it should suffice, if the wind came from the west, as I think).

          The question is if this is part of Askja or Fremrinámur systems, I found different information on that.

        • It’s midway between Hammarin, Hofsjökull, Trölladyngja(?) and Bardarbunga. Also, it’s one of the closest SIL stations to the Dead Zone. Last spring it was doing similar stunts & some thought it was related to blasting for the turbine tunnels of a hydroelectric plant, but – again IIRC – that didn’t fit the bill. Pity Vatnsfell is out of order as that showed the same thing last spring.

          • As far as I know, there was some construction work going on for a hydroelectric power station. But I don’t think out in nowwhere they would work in the middle of the night – and in the winter time, too. And one of these spikes seems to start around 2:00 in the morning. And also with this tremoring going on at Bárdarbunga … But I am no expert (hi Daily Mail and Scaremongerers 🙂 ).

  9. Anyone been able to get anything out of KVERT or emsd.ru? It’s been down all weekend.

    Snippet from Klyuchi observatory today reports that Tolbachik eruption continues at a lower rate, and they also report the shallow swarm of earthquakes to the southeast of the eruption that began a couple of days after the initial fissures opening up, and which we saw on the quake maps (would really like to see the latest quake data).

  10. Exciting, suddenly so much going on!

    Here are screenshots of a 3Dplot from the recent Rhodos – Bozburun earthquakes and the activity going back to 1964. That is a pretty distinct blob (around 850 events in appr. 10 km diameter during the last 22 days) going all the way down to the Moho.

    Previous large earthquakes are pretty much all over the place, there is an accumulation about 25 km north of the current swarm.

    Local earthquake data are from http://www.koeri.boun.edu.tr/scripts/lasteq.asp (cold-warm),
    previous events above 4 (different units of magnitude, gold) from 1964 to present are from http://www.iris.edu/servlet/eventserver/map.do.
    Topology from Geodas design-a-grid and the Mohomap from seismo.helsinki.fi

    Top view: http://i45.tinypic.com/178pxt.jpg

  11. woah…. good morning everyone (yeah, I know, it’s ten to 4 in the morning here, but I went to bed early 😉 )

    can someone fill me in about Nisyros? Those tremor signals are shouting “eruption in progress” but where is it? The swarm over at Symi is unlikely to be the site as it is only in about 300m of water and would certainly have been noticed by now. (though imagine the squabbling between Turkey and Greece is a new island connected Symi to the Turkish mainland!!)

  12. And it gets better. Nisyros isn’t just a caldera forming system. It is a periphery system sitting on the ring fault structure of the Kos Caldera.

    Kos Caldera is a trapdoor structure, about 22.5 x 17.5 km. It erupted about 160,000 years ago and according to my estimate formula, could have been in the 234 cubic kilometer range…. but I haven’t found any actual data, thats just what the dimensions point at. As I have mentioned before, all that didn’t nessesarily come out at once. Within the Kos Caldera there are two large depressions that could have been other events that were part of that 234 cu km estimate.

    I’d post links, but I got frustrated and went to bed. In summary… its more than just another caldera volcano. Its a freaking system of them… again.

      • Quote from the Sikioti paper (the last one):
        Mogi model indicates a source at 5km depth beneath the north-west edge of the island, with a maximum deformation amplitude at surface of 0.14 plus or minus 0.02m and a total volume change of 26 plus or minus 4 × 106 m3, during 1995-1997. The Okada model indicats a dike solution 2km long, 2.2km wide, wiht a 4m opening and a 30° dip. The upper center is at 6.4km depth and the volume change, also during 1995-1997, is 17.6 × 106 m3.

      • Nisyros is a scary volcanic system.

        Not only is it huge, but it also is an island in the middle of the sea. There are a lot of huge caldera systems around in the world, but there are only a few that are of this size, and also sitting in a gigantic bucket of water in a populated area of the world where many would be affected by eruption-induced tsunamis.

        Honestly, this is a volcano that even us volcanoholics do not want to see erupt. Think Ischia / Campi Flegrei / Santorini style eruption if it were to perform a full scale eruption.

        • Since my last comments about signals in the North west of Vatnavotn I have tried rooting out some GPS results but unfortunately nothing for 2012. I know Carl had managed to contact Sigrun Hreinsdottir who was most helpful. She is Iceland’s GPS expert contact. Hekla and Katla GPS is easily found on their monitoring pages but I really can’t find anything for anywhere else.
          Sigh! Yesterday I lost a whole morning’s listings when ebay’s listing tool completely froze my PC and wiped all my data from my PC. Today I start again having at least found some archived listing data. Now this morning I have failed to satisfy my curiosity ( another sigh!). Today the cold, sleety rain is falling. I really want to go back to my nice warm bed and hibernate. One plus (or minus, depending how you look at it) of having a bouncy, fun filled young dog is that retiring back to bed is not an option, and so work beckons even at this god forsaken hour!
          Nisyros ! All new information for me and yes indeed it’s scary but horribly fascinating.

          Coffee #2 calls.

          • Ok. Time for update (my opinion).
            Jök SIL is showing interesting things, probably one of two possible: Sudden (rapid) “Jökull Crawl” in neaby Vatnajökull or sudden (mild) intrusion in Dyngjuháls (not Bárðarbunga, I think, doupt it whould show this way). Gilhagi looks similar to an intrusion at depth (but might be water/freezing/underground/flooding or whatever), VAT SIL indeed has 24/7 construction ongoing nearby. Last week they were digging (blasted) thrugh the last section of 4 km tunnel (upper level) for that Hydro-electric plant.
            Next six months be digging that tunnel to full “height” (digging out lower “level”) and filling in of the 2 km long dam. Else there seems be NO volcanic signals in the charts. Dissapointing? Well, who promised disasters here in late 2012 ? No one, but some scare-mongers probably (and they most probably are wrong).

          • Arrrghhhh! I mean Vatnajökull. Sorry Everyone and thanks IngeB for pulling me up on this. Was a little stressed earlier!

          • @Diana. No problem. Are we not all a little stressed over things sometimes? Have a nice one like this: http://commons.wikimedia.org/wiki/File:A_small_cup_of_coffee.JPG

            @islander the turbo.
            Yes, could be that Dyngjujökull is surging again. He has been doing this in the past. See: http://www.ingentaconnect.com/content/igsoc/agl/2005/00000042/00000001/art00004 (abstract)
            And if it is an intrusion under Dyngjuháls, that should be part of Bárdarbunga, or not? 🙂

          • Dyngjuháls (from: http://www.nat.is/travelguide/ahugav_st_dynguhals_ferdavisir.htm , regrettably not in English): It is a long ridge reaching out from under Dyngjujökull (glacier) in direction of Trölladyngja. – And Dyngjujökull is the most important outlet glacier of Bárdabunga. – There is a difficult jeep track with a traverse at 1220 m height.

            No less than 5 crater rows are located on the ridge, 5-10 long each.

            The volcanic system of Bárdarbunga streches about 70 km also in northeastern direction from the glacier volcano, this is the longest volcanic sytem in Iceland (ca. 190 km – http://www.geo.mtu.edu/~raman/papers2/Thordarson%20and%20Larsen%202007%20-%20Volcanism%20in%20Iceland.pdf Thordarson / Larsen (2007), p. 7 and map p. 5). But Larsen e.a. mention that only 3 of 23 holocene Bárdarbunga eruptions have been taking place in the icefree northern part of the system. (Holocene volcanic activity at Grímsvötn, Bárdarbunga and Kverkfjöll subglacial centres beneath Vatnajökull, Iceland (2011), p.3).

          • Ah, agree on “Glacial Surge” (thats the word, thanks Inge B, but I am not “The Turbo”, much more powerful, rather Tubo as last part of Mt. Pinatubo, so added ´ there for all better understanding the “pun”) and yes, of course, TFZ is still active, no cancellation on IMO (“Uncertainty Phase”) alert there. Granastaðir SIL look about what I think it should look like, nothing more or less. So maximum expected this year might be.. a quake or two (shure, now temping fate, but likely it takes no notice)…

        • Considering all the things it has done in the past, a Nisyros eruption is nothing short of “Volcanic Roulette”.

      • The effect of Perigussa Ring Fault (PRF) on the Nisyros Edifice

        • The intersection of this fault with the bounding fault of the apical block of proto-Nisyros and/or with a radial fault could have provided the passageways necessary (Fig. 6) for the ascent of the andesitic magma which erected the subaerial pOltion of the Nisyros stratocone.

        • ‘Trap-door’ rotating motion on the PRF could alternatively submerge or emerge the northwestern portion of the island. Such a rotating motion has presently emerged basaltic andesite pillow lavas and pillow breccias under the old castle wall near Mandraki. Submerging motion in the past would account for the lack of units at the high and medium positions of the volcanic stratigraphy, resulting in exhumation and exposure of unit 19 which has constructed the main body of the subaerial Nisyros protocone.


        • That grabben structure is roughly aligned over the 120-130 km deep region of the subducting plate. I noted that the alignment of the dominant magma intrusion is along that similar bearing… which is also the rough alignment of that part of the Kos ring fault.

          • So the question here – Is this Kos / Nisyros reactivating, or is this tremor related to the “new” volcanic structure some are suggesting further east and closer to Turkey?

  13. Ahh yes, the problem that has vexed mankind for hundreds of years is still here, perturbing our logic and making us question our very existence…

    “Okay, I just poured my coffee, where the %*#$ did I put it?”

  14. Has somebody been having a look at Icelandic SIL station Granastadir (GRA) lately? There is this earthquake swarm still ongoing on TFZ (Tjörnes Fracture Zone), but it’s on the other side of the peninsula Flateyjarskagi. And GRA is placed at the southwestern end of the Skjálfandi Bay not far from estuary of Skjálfandafljót. And it is really rather lively also in the red frequencies. http://hraun.vedur.is/ja/oroi/gra.gif

  15. FYI – MRK over at Eruptions noted a large IR bloom off the satellite in the Kamchatka Peninsular. Georeferencing the image puts the plume in the vicinity of Tolbachik, but nothing is showing on the cam.

    Yes, the cam is updating, analysis of the difference in two separate pulls of the image show normal background noise accumulation… so the feed is hot.


  16. Great to get the quake data back. The swarm that started a couple of days after the Tolbachik eruption, to the south-south-east of the fissure, appears to have kept going for some time – see screengrab below, but now seems to have stopped.

    Regarding the destroyed science stations: the EMSD shows only one station near Tolbachik, coded KMN (presumably the Kamenistaya station I mentioned earlier). This would imply that the two that were destroyed either did not have seismic equipment, or that they did not feed into the EMSD network.

    Edited by Kilgharrah

  17. Arternoon All,

    Just googled the Corona/ Lava Tube paper (Carracedo et al) referenced by Ukviggen int’ article (Looking in vain for a nEnglish version; my Spanish is newspaper level on a good day, not technical…) and Volcanocafe had the top 2 spots (of 113.) No wonder Sr Carracedo hasn’t complained about us, he’s getting good, free publicity!!!

    Now I have pondered a little; I realise that I’m probably not the first Volcanocafer to try this, so we’re also publicising ourselves pretty well 😀

    I’m a very slow/ poor typist and a bit of a perfectionist, which means that my brain tends to be ahead of the game; this leads to revisions, additional rumination, and proof reading. It can get a bit cyclic… this comment is about 10 minutes work. Don’t ask about the articles 🙂

    To be fair my typing is improving…

    And apparent typos are usually deliberate…

  18. Hi

    Here is the Grimsvötn earthquake animation for 2011 and 2012

    I wonder if a little zooming could be in order.
    There is a nice sill like formation in 5/2011 nearly under Grimsvötn I think.

    On the second part the color of the dots is age related (red is most recent, blue oldest)
    I have added some of the locations Inge gave me for better readability.
    Rocking chair effect is still in the positive only for easier reading.

  19. And since it’s schnowing, I think it’s fair to mention Xmas…
    For those of you who haven’t already posted letters to Santa:
    Gates n’ Ritchie’s Encyclopedia of Earthquakes n’ Volcanoes…
    I thought to myself; I’m not really up to schpeed with Nysiros/ Nisyros… So I looked it up. I had the same thing with Lokon (and the caldera), Seismograms, Schtratovolcanoes, Beach Balls, Rhyolite etc
    Highly recommended 🙂

    • Not my data. I just knew how to lift if off of their page. 😀 (it’s not a hack, the data is just buried in their Javascript.)

      I can do a fresh pull later if you need.

      • Ah, just found the non-hack. Copy-paste from the event window into word and get rid of lots of  </ reveales the list 🙂

    • I would really love seeing a close in sequence from when the two sill pancakes started. THAT ought to be interesting.

      It might also illuminate how the jump was made from one sill to the next at that point that I called off… which happens to lie directly under the Eastern summit/flank of one of the Tolbachiks.

      • Well I’ll have a go later when this run is finished (and there’s Grim too to do).
        Also the data you supplied was a bit corrupt (or it’s a bug in Ocyave) and that’s why it took so long to get something working (in fact the geographic coordinates, I do not know why, are being recognized by Octave as complex numbers, but I got that fixed)

      • i think dfm uses Octave. Its an open source MathCad work-a-like that actually is a bit more feature rich. I don’t think it can directly read Excel, though it is possible that someone has made a pipe for it. Being open source, it’s pretty easy to extend it’s capabilities and people do it all the time. I do know it can pull a csv… but WordPress won’t let me upload a csv to the site. Csv files are da bomb. Just data, no fancy stuff. Great for sharing data sets across platforms.

        Btw… it’s free. You can use it under Windows with Cygwin.

      • Octave is effectively a language. As such, it is very powerful in what it can do. It’s focused mainly on general math, and can deal with imaginary numbers quite easily. (probably why it wanted to treat some of the data as imaginary numbers)

        A language specifically geared for stats, is “R”…. also open source, also free for the simple users…. like us.

        In “braindead” mode, Octave can use program, scripts, and packages made for MathCad.

      • Deviating a bit. Imaginary numbers aren’t that scary. “i” is defined as the square root of a negative one. Anytime you have the i operator…. thats what it means It’s similar to the “j” operator when you are doing math with reactance values in electronics. After everything is said and done, you can convert that into a phase angle and find out what the voltage to current lead or lag is for when go in and actually measure it.

      • Well I do use Octave. I “discovered” it a bit more that a year ago because I wanted to do 3D graphs of earthquake for El Hierro adn Excel was not up to the task.
        Also there were the density plots.
        The big points are that it’s pretty powerful, can make good graphics and.. it’s free !
        Transferring data directly from Excel is doable, but I prefer to use csv as there seems to be less compatibilty issues.
        I’m also using it under Linux because I tried the Windows version and was not convinced (I got difficulty with generating graphics in fact).
        The only drawback that I see is that it really does not like loops and that’s what I need if I want to make animations, that’s why getting the results is quite slow.
        FYI for Tolbachik I’m up to 1926 out of 2679 events….I will try to use another function (plot instead of scatter) but we will loose some information.
        I know of R, but there is also Python which seems a pretty powerful language (and free too which does not hurt)

      • PS: Mind you, this is just funny re. the a.m. picture.

        At the moment, there seems (acc. to webcam) an ash cloud descending over the region, and this is of course not funny at all. Have been in something like that myself and know a lot about it.

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