A Tube’s Tale: Part 1 – formation

Beneath this featureless volcanic wasteland runs one of the longest lava tubes in the world – reaching all the way from Monte Corona in the distance to way out under the sea.

Lanzarote ranks as one of the most obviously volcanic places on the planet. The island is liberally sprinkled with craters, cones and lava fields. The dry, frost-free climate means that volcanic features weather only slowly, and vegetation has had a hard time gaining any meaningful foothold on the land.

Around 15.5 million years ago the island became the second of the Canaries to emerge (some time after neighbouring Fuerteventura, although geologically they are essentially the same structure), as a postulated result of continental drift over the Canarian hot-spot. Drift pioneer Alfred Wegener visited Lanzarote in 1912 months after he had first presented his theory of continental drift. His studies during his time on the island added weight to that theory.

The last major eruptive episode occurred between 1730 and 1736, when a fissure opened up in the west of the island to produce 24 main vents and several smaller ones that ultimately covered 23% of the island’s area with fresh lava. Three more vents briefly erupted in 1824 along the same general alignment, as part of what J.C. Carracedo et al described as a “structural rift-type zone”. The 18th century eruptions were not only devastating but also of great interest, particularly as they had been the first on the island for many millennia. They were possibly the last throes of a volcanic island-building process. But what had happened before that?

Corona volcanic group

As in many Spanish-speaking regions, the lava fields are known locally as the ‘malpaís’, literally the ‘badlands’. One of the largest areas of malpaís occupies the northeastern tip of the island, and is now designated as a ‘Monumento Natural’. The Malpaís de la Corona was produced by the Corona volcanic group, dominated by Monte Corona itself and incorporating the smaller, older volcanoes of La Quemada and Los Helechos. These two volcanoes grew out of the Miocene shield volcano of Famara, with Los Helechos dating to about 91,000 years ago.

Viewed from the beach at the northern edge of the Malpaís de la Corona, which was formed by the third major flow from the volcano, Monte Corona looms large over the surrounding region. On the right is the much older Volcán La Quemada, which had covered much the same area.

Corona almost certainly provided the most recent eruption on the island prior to the 1730-36 and 1824 events. Until around a decade ago its eruption was thought to be as recent as 4,000 to 5,000 years old, based largely on the apparently ‘young’ condition of the lava field. Several sources, including official tourist handouts, continue to state this age.
However, and bearing in mind the prevailing lack of weathering on the island, it was more recently suspected that the eruptions had happened much longer ago. Accordingly, modern Argon (Ar39/Ar40) dating techniques were employed, from which it appears that Corona was active around 21,000 ± 6,500 years ago. This coincides neatly with the last glacial maximum between 18,000 and 21,000 years ago, when sea levels were at their lowest. The significance of this is explained later.

The Corona eruption left a large crater, standing 609 metres at its highest point, with a slight collapse on one side. As well as spilling westwards down the spectacular Famara cliffs, lava from Monte Corona fanned out over a wide arc to the east, creating an extensive lava field that reached to the sea along around 15 km of the current coastline. The flows (‘coladas’) were actually bigger at the time of their creation, as the coastline has retreated with the rise of sea level in post-glacial times.

Following on from the initial explosive and cone-building activity, three separate flows from Corona have been identified, the first and second partially overlaying the earlier flows from Volcán Los Helechos to the south, while the third – more viscous and more extensive than the previous flows – formed an a’a landscape that almost completely overlaid the lava field of Volcán La Quemada to the north.

The Corona tube

Within the Corona ‘coladas’ is one of the many natural wonders of Lanzarote: a lava tube that extends from the base of Monte Corona out to beyond the current coastline. In total the tube stretches for nearly 8 km and is the world’s 15th (some sources say 16th) longest lava tube discovered to date.

Alignment and features of the Corona lava tube (image ©Google, annotation by author)

Created during the first effusive phase of the Corona eruption, the lava tube formed in a flow of fluid pahoehoe basalt that emanated from a lateral vent on the eastern side of the volcano, which also formed hornitos. The tube travelled roughly ESE toward the sea.

Lying under the Corona lava flow is a layer of lapilli from the initial explosive eruption, which itself lies above lava from Volcán Los Helechos. Examination of the tunnel walls suggests that the Corona lava stream that eventually formed the tunnel followed the course of a gully in the underlying Los Helechos lava. Successive pulses of pahoehoe lava built up the sides and eventually formed a roof, buoyed by gases from the flowing lava. Subsequent lavas buried the tunnel further.

Flowing lava smoothed the walls of the tunnel.

As it nears the sea the tunnel dives over the end of the Los Helechos lava, leading to a more complex space with up to three chambers at varying depths in some sections, a result of internal collapses, false floors and re-routing of the flow. The tube ends abruptly in a large chamber that is 64 metres below current sea level.

Marking the route of the Corona tube on the surface are 21 jameos, the local name for a hole in the ground where the roof of the tunnel has collapsed. The jameos provide access to the tunnel, which is typically 20 metres wide, although up to 30 metres in some sections.

It has been postulated by Carracedo et al that the tunnel and lava flow originally ended where it met the sea. Studies of similar activity in Hawaii and elsewhere in the Canaries suggest that it is highly unlikely that the tube could have continued forming under the water, where a ‘lava delta’ without tubing is a more typical formation. There is evidence of some explosive activity at the seaward end of the tunnel, consistent with hot lava mixing with seawater.

Consequently, it can be deduced from the volcanic evidence alone that the tube formed above water, and that therefore the sea level was much lower 20,000 years ago than it is today. This is entirely consistent with the coldest phase of the most recent glacial period, when much more of the planet’s water was locked up in polar ice-caps and sea levels were up to 100 metres lower than where they are today.

In the following part the more recent history of the tunnel will be explored.


Hi Volcanoholics!
This week would have been more exciting than many, lately ( if i would have had time to research or watch cams.)
Mt. Lokon erupted again and georgiade provided a webcam. ( check the last thread)

UKViggen, the author of the post above, keeps us updated on Tolbachik which is set back to alert level orange ( from red) even though a new fissure might or might not have opened. A collection of beautiful images can be viewed on http://www.kscnet.ru/ivs/kvert/current_eng.php?name=Plosky%20Tolbachik.
Please check out this KVERT page about the current status of the volcanoes in Kamtchatka: http://www.kscnet.ru/ivs/kvert/current_eng.php
Obviously Santa Maria in Guatemala erupted. Erik Klemetti ( a real expert! )  devoted a post on it on his blog Eruptions: http://www.wired.com/wiredscience/2012/11/ash-fall-and-pyroclastic-flows-from-guatemalas-santa-maria/

As an ADMIN of this site, i want to state some clarifications because quite some emails reached me.
1. Carl is absent and we do not know where he is or what he is up to. I sure hope he is coming back soon.
2. Lucas Wilson is a regular READER and i/we published 2,5 posts by him but he is not a dragon (Editor) or has any influence on what we publish. He is still welcome to leave comments, but if the advertising other sites gets out of hand …
3. I am asking all people here to refrain from talking about Religions or something similar. This is a VolcanoCafe! The main topic is volcanoes, eruptions, earthquakes and the like. OT chat is of course allowed, but i really do not want to see talks about religion here. Let me say it like that: I believe Volcanoes create and destroy. This is fascinating. Let people believe whatever they want to and what makes them happy and does not harm other people.
If someone feels he/she still must go on, dragons… delete that!!!

And now to the normal Friday entertainment. AlanC and Suzie provided riddles. I know the answers to Suzie´s riddle but not to Alan`s.

RIDDLE – Name those Volcanoes!
The first shares its name with a US Armed Forces gold medal
The second was also a 1990s top-rated, psychological TV thriller
The third suggests a digitally challenged Black actor
The fourth claimed a European victory for Ireland in 1970
The fifth could have been, but wasn’t, named after Chekovs’ Masha
And finally, for the numerologists, the sixth can be represented as 16916042108

6 in words SIX points to be gained this time. I also received a hint but that will go in later.

Alans evil riddle!!

Dead straight, this one ‘ll stick to you!
What am I?
My composition?
Where am I found?

Happy reading and hunting.

Have a nice weekend.



341 thoughts on “A Tube’s Tale: Part 1 – formation

  1. @UKviggen
    Hmm I’d rather forget the last time our teams met! I will be at the match and am hoping for revenge but not exactly optimistic!

          • Totally OT. I’m coming down that neck of the woods this week. Daughter looking at So’ton Uni. Sussex (Schteve?) last week and So’ton this week. Not far enough away from home for my liking!! 🙂

          • Puncheon? I think you’re confusing the mighty Royals with the ‘Fake Hoops’ of West London. The three of us, however, have a destiny to all meet again in the Champo next year. At least the season ticket prices will be affordable.

  2. 169 Mt, 16 S, 0 H, 42 As, 108 Ta
    That was a pain: Looked for ages for a periodic table of elements including neutron numbers…unsuccessful. Had to resort to mental arithmetics, that´s so retro 😉

  3. Dings/points for last nights’ riddle now complete- well done UKviggen, Stoneyard, DebbieZ, Inge B, Alison, Chryphia and Sissel

  4. Ok I am not much on riddles spent most of the afternoon thinking ’bout the last Mountain
    AH HA! Shasta! Eureka! or more appropriate Yreka -it’s closer. I get home from running
    store to store fire up the ‘ol Toshiba and…..
    Now throws John Cleese like fit-( Basil Faulty) Wife laughs Springer hides in Kennel…
    Dang it!
    Anyway here is another US Lava tube area the Malpais monument of New Mexico.
    Played whack-a-mole with a fire there once.,It would travel in debris/brush filled
    tubes and cracks finally with a lot of effort got it corralled but not fun for ground and
    air. Anyway: http://www.nps.gov/elma/photosmultimedia/photogallery.htm

  5. marktburns over at Eruptions triggered on a swarm in the lower end of Owens Valley California.

    Slap dab in the middle of the Swarm is the Coso Geothermal plant. It is in a line of cones that snake back and forth up the southern end… known as the Coso Volcanic Field.

    Owens valley is a grabben. It’s probably the most western part of the overall Basin and Range structure.

    Hydrothermal Plant related? Well.. maybe. But some sort of rifting made the volcanic field on the southern end, and some of these small quakes were quite deep.

    • Vaguely remember from the geothermal plant near Hengill, Iceland, that quakes from geothermal operations are supposed to be no more than 1 – 2 km and not very big.

  6. Another try at Alan’s sticky riddle:

    Paragonite: “also known as Natron-Glimmer, is a mineral, related to muscovite. Its empirical formula is NaAl2[(OH)2|AlSi3O10]. A wide solvus separates muscovite from paragonite, such that there is little solid solution along the vector Na+K+ and apparent micas of intermediate composition is most commonly a microscopic (or even sub-microscopic) intergrowth of two distinct micas, one rich in K, and the other in Na. Paragonite is a common mineral in rocks metamorphosed under blueschist facies conditions along with other sodic minerals such as albite, jadeite and glaucophane. During the transition from blueschist to greenschist facies, paragonite and glaucophane are transformed into chlorite and albite.

    It was first described in 1843 for an occurrence at Mt. Campione, Tessin, Switzerland. The name derives from the Greek, paragon, for misleading, due to its similar appearance to talc”
    Source: http://en.wikipedia.org/wiki/Paragonite

    • & Tellurite: tellurium dioxide (TeO2).

      “prismatic to acicular transparent yellow to white orthorhombic crystals. It occurs in the oxidation zone of mineral deposits in association with native tellurium, emmonsite and other tellurium minerals. Its name comes from Tellus, which is the Latin name for the planet Earth.”

  7. I… have an idea.

    Those of you who also ruminate… think about it for a while. Those that can wrangle data, do so in order to see if you can expand on it.

    Kamtchatka has a lot of volcanoes. Tolbachi went fissure vent/row and erupted what appears at the outset… to be mafic magma. (I could be wrong, it might be really really hot, but gas poor felsic material… which would have a different meaning)

    But… to the North is a wad of quakes that are associated with another volcano. This group is about 30 km deep.

    Here is my idea…. first, as noted, they two systems are not related… on the face of it. However, they do share a common feed source… the subducting Pacific plate.

    In the case of the system to the North, the magma impinges on the bottom of the crust and pools, allowing it to fractionate and/or remobilize old magma. As you have seen in my thermal simulations (KWares “Heat3D”), intruded magma can take thousands of years to loose it’s heat and cool below the solidous point.

    To the south, the system is pretty much open.. and still open for whatever reason (extensional forces of some type) so, when the new magma arrived from below, it punched right on through.

    Its a thought.. could be wrong. Might be right. ‘yall think about it.

    • Makes sense to me. It is basically the same question I posited in the TVZ series. The eureka moment came for me when I realized the question was not why there was a basaltic eruption (and plinian at that) in the TVZ (talking about Tarawera). The real question is why are these not happening ALL the time. You have a mantle wedge tucked up closely under thin crust in an extensional setting.. this thing should be spouting basaltic floods like Laki. That’s when I realized the crystal mush in the zone must be fairly widespread, at least widespread enough to act as a spongy cap to trap and entrain any mafic intrusions, which then leads to more melting and large shallow chambers of crustal melt.

      In Kamchatka, I think the mantle wedge must be pretty close to that 30 km deep swarm under Kliuchevskoi as the entire area underneath it is pretty silent. I suspect that the 30 km swarm under Kliu marks a deep chamber with some stoping, dike intrusions, sills, etc. going on. This could be the source of the andesite that gets erupted or maybe there is another chamber at higher levels, but whatever, the rate of mafic input related to the rate of magma output (eruptives) is high enough to stop rhyolite forming. OMG… just checked GVP: Kliuchevskoi (which is the only 4800 m high) formed in the last 6000 years. (picks jaw up off floor)

      And yes, I agree, at Tolbachik, the mantle wedge has found a way straight through the crust.

      • or another idea…. if the systems are connected at depth down near the mantle wedge somewhere.. and given that Klui is 4800m high.. just perhaps Tolbachik represents some kind of fissure release, like you see at Katla (just tossing this idea out there – and, btw, take note that it is NOT corroborated by the behaviour of Kluichevskoi which remained extremely active even after the 1975 Tolbachik eruption).

    • Since you brought it up…

      (coloration added to emphasize key points)

      In 1975, volcanic earthquakes initiated by an activated 20km deep magmatic source in Kamchatka were detected. Ten days later, a basalt magma with an inflow rate of 630 kg/s reached the Earth’s surface through a network of fissures. This event is known as the Great Tolbachik Fissure Eruption. To describe the dynamics of magma flowup through a set of fissures, the Brinkman hydrodynamic resistance is introduced into the Navier–Stokes equation. A model suggested in this work allows one to relate the earthquake source depth, the time of magma flowup to the Earth’s surface, and the velocity of the magma flow through a set of fissures. The inflow of the liquid is calculated, and the calculated value is in good agreement with field data.


    • And then it got interesting.

      This is that same data set from earlier, but stuff out of the area is tossed out, and I set the max depth at 35 km.

      The swarm doesn’t seem to run into the previous fissure area… odd.

    • Has anyone done any analysis of the magma/ash type yet? Probably will
      take a few days . You are making sense, Lurk..If it was Felsic that would
      mean that the source was from an uplifting source possibly not as deep.
      Mafic is probably much more likely…

        • The way I read this… Tolbachik has two sills, pancake style. One at about sea level, or 1000 meters deep, the other about 3100 meters deep below sea level.. or about 4100 under the surface. They seem to connect at about Latitude 55.816°N 160.407°E, or at least draw very near to each other. Pretty much directly under the eastern edge of the edifice.

      • Enigma doesn’t’ even come close…

        (coloration added)

        …When primitive (Mg#, i.e. Mg/Mg + Fe2+) molar[0.65 or more evolved (e.g., normalized
        at MgO = 6 wt%) CKD are compared. Klyuchevskoy rocks have compositions intermediate between basaltic Tolbachik volcano in the south and Sheveluch volcano in the north, the latter having the most silica-rich ‘‘adakitic flavor’’. Portnyagin et al. (2007b) and Portnyagin and Manea (2008) interpreted the compositional peculiarity of Klyuchevskoy rocks to reflect either relatively low equilibration temperatures of parental Klyuchevskoy melts with mantle peridotite or mixing of primitive basalts with evolved silica-rich melts in shallow conduits or magma chamber.

        Perhaps the most intriguing aspect of Klyuchevskoy, Bezymianny, and CKD volcanism in general are the unusually high-d18O values of basalts, the highest in the world. Kersting (1991), Pineau et al. (1999), and Pokrovsky and Volynets (1999) reported d18O whole-rock values of 5.5–8.5%, which range from normal mantle-derived basalt values of 5.7% (e.g., Eiler 2001) to up to 3% higher

        The origin of hydrous, high-d18O voluminous volcanism: diverse
        oxygen isotope values and high magmatic water contents within
        the volcanic record of Klyuchevskoy volcano, Kamchatka, Russia
        ” Bindeman et al 2008

        • Aside from being similar to mantle material… one possibility could be from the water that was entrained or taken up into the oceanic crust from millions of years ago. (via Hydration or contained in the pores.) The 18O/16O (oxygen 18 to oxygen 16) ratio has a tendency to change depending on temperature and is used as one of the temperature proxies when analyzing ice-cores. Its possible that the oceanic crust… in this region, some of the oldest on the Earth, may be skewing the chemical make-up of what is being seen from the volcanoes.

          Again.. just an idea.

  8. Ahem,
    I came online to publish the next edition of UKViggens LavaTube as a brainfood for the weekend. … But the discussion here and now is fascinating Thank you GeoLurking. And would be lost if i press the publish button.
    So tell me what to do.

      • Thats what i was thinking too. So .. part 2 8 a clock tomrrow morning. (CET)
        And if i get this darn computer to work correctly, maybe store some comments in the comments too good to be lost section

        • This is a test to ensure that I was able to delete the posts requested by Inge B. without breaking the forum.

          Looks like it worked.

          Note: you have to start at the last post of the subthread and work backwards.

      • Sounds cool. I’m pretty sure that some ruminations about this are in store. I have some answers… but I’ve pretty much stated those. The rest are questions.

        (like that Oxygen ratio… I don’t even know if my idea makes sense geologically)

        PS: I’m quite pleased at that ball of deep earthquakes… that’s neat!

        And its off to bed for me. I played hookey at doing my inventory and I have to get it done tomorrow… so I have to actually sleep for a change.

  9. Well I’ll be dipped in ####.

    Guess what else is under the odd chemical signature volcanoes.

    The subducted remains of some of the Emporer Sea Mounts. They were made by the Hawaiian hotspot.-

  10. OT rumination then… we currently have high levels of carbon dioxide in the atmosphere – deemed anthropogenic, though longer historical records suggest it has been higher in the past, and suspicion falls on volcanoes for that, but oxygen levels have also been higher. The simple equation I had understood for the dynamic was that high oxygen levels encouraged forest fires which produced carbon dioxide, and then trees produced oxygen – but – does this fully account for past oxygen levels rise, in the cycle?

    Is oxygen sometimes one of the gases emitted by volcanoes? Or am I being particularly dense here, given what we know about sulphur, fluorine and carbon dioxide emissions……… etc etc

    It is quite something to try and imagine magma erupting so high – ash yes – but liquid magma is pushing one heck of a consistent pressure to get it to 1.5 km!

  11. In south Iceland, near Katla, they are planning to build a new dike to protect further the road and nearby farms. You can see their designed plan in http://www.vegagerdin.is Seems to be only one dike, along the western side of Múlakvísl river. Not sure if it help much, but surely the dike seems to be placed in the right alignment, in order to be able to stand the force of the flood waters.

    • I saw it and deleted it – it was an Italian Holiday company selling holidays and homes near to Volcanoes. An interesting concept for the ‘I live dangerously’ set!

  12. Wish I could hang around with you lovely people this afternoon, but alas I have to go work 😦
    On a more cheerful (OT) note, did any of our Kiwi friends see the match yesterday? 😀
    Let’s just say I was up rather late celebrating…

    • Wish you joy albeit considering the 45 – 3 (million) population advantage, as well as home advantage (Twickenham), wouldn’t you agree that 38 – 21 was rather a poor result? 😛

    • Thirteen of the All Blacks suffering from Norovirus (otherwise known as Winter Vomiting) so not really an indication of where either team stands internationally.

      • Whatever the reason the All Blacks didn’t appear to play to their usual standard. A well deserved win by England for once, nice to see the team back on top form.

      • Evenin All,
        @ Newby, yes an excellent result and very well played Engalnd.
        @ Oliver Sinjen Mollusc, but in New Zealand almost every little lad dreams of playing for the All Blacks, in England almost every little lad dreams of being a soccer player… And the Kiwis are world champions despite their small population.
        @ Talla, I hear what you are saying, but the All Blacks have refused to use the vomitting outbreak as an excuse, so I will not do so for them…
        Of course next time around they may well give us a thrashing, I’m just pleased to see the England side (hopefully) beginning to get over the World Cup debacle and start the process of rebuilding the team 🙂

        • It doesn’t happen very often, so let us/them (me? I have a green tinge to my blood) enjoy it for a little while!
          According to my mate who was there, England were f***ing great!

          • I agree, I didn’t see the match but the highlights alone, coupled with the statements from the All Blacks makes it sound like England thoroughly deserved the win. Well done England! (and yeah, we’re not going to let a trifling matter like population stop us 😉 Bring it on!)

    • Really nice, thank you, Dfm. 🙂

      There are clearly to be seen some feeder systems. The most explicit one is under Askja and a bit to the northeast of her. Perhaps you could add here the positions of Herdubreid (65.18 N, 16.34) and Herdubreidartögl as well as Upptyppingar.

      And under Vatnjökull, there seem to be some sort of vertical sheets.

  13. My stab at Alan’s riddle. Orthos is Greek for straight so I’m going for Orthoclase (chemical compound KAISi308) which is a twinned crystal – so it sticks or adheres. It’s found everywhere so I don’t think this is the answer but it may point the way to others who aren’t struggling with Christmas card lists and toothache. 🙂

  14. This one’s a bit close to Eyjafjallajokull
    02.12.2012 21:11:45 63.634 -19.542 14.0 km 1.9 66.24 5.7 km SSW of Básar

    • Albeit deep, it’s not been checked yet. Should it turn out to be that deep once checked, it is interesting as it could be a sign of the conduit settling down post-eruption. Or much less likely the opposite.

      (I always wait until the quality goes up to 99.0% ( = checked by seismologist) before I get excited. What usually happens to potentially interesting quakes is that once checked, they turn out to be nothing like the first, automated response.)

  15. Interesting that H105 on El Hierro has deflated about 6cm over the last week or so. Chart shows a bit of a yo-yo effect since October.

    This is quite dramatic – I’m assuming that the pressure has dropped at the southern end of the Island but we still have a lot of red in the 1Hz band which seems at odds with the deflation chart. A peak of activity on the Gran Canaria chart at midnight last night
    El Hierro still has us guessing

    • Hmmm…..HI02, HI03 and possibly FRON may have inflated. Difficult to tell what is happening.

      The cyclical pattern you are seeing may be inflation followed by gravitational deflation – need a real expert to say, as I am just guessing here. 😕

  16. Hi KarenZ
    Yes there did seem to be marginal inflation in others – but to see such a drop in H105 seems a little odd in this one small area – unless the sensor is playing up.
    Off to bed now – goodnight all

    • Good luck with going to research that.

      Greece will be all over them like stink on hooey.

      It’s an interesting phenomena. Whenever we did exercises with the Greek ships, the Turks would shadow the formation. Whenever we did exercises with the Turks, the Greeks would shadow the formation.

      It’s almost like they don’t like each other very well.

      • Merhaba! Good observation. Sure looks like it. Neither do they seem to like very much the Armenians and Kurds. But the food is great. Köfte, Börek and Ayran. Yet it would be interesting to see a visualization of what is really happening down there. Are there any data out there?

        • Oh, this dates back much farther back, ever since the Trojan War; followed by the chism between the Byzantine and Roman church where Greece and Turkey became Byzantine; then came the rise of Islam when the Christian infighting extended into the Crusader period that culminated in the fall on Constantinopel; then came the rise of the Ottomans who later conquered Greece which then in 1821 freed itself from the Ottoman Empire – which is only the source of the latest incarnation of Greek-Turkish mistrust & hatred…

    • Not that tough; I’ve walked over flows that were only a few days old in Hawaii. Warm work, but nothing outrageous. And at this time of year the weather in Russia is usually a bit brisker than in Hawaii…

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