Teneguia: Technicalities and Context.


http://www.youtube.com/watch?v=MQ-7HwZyOVs (from Miguel Bravo’s youtube channel; well worth perusing)

You may want to mute it; but I kinda like the music…

The 1971 eruption of Teneguia, La Palma is well documented/ analysed, so presented here is an “abschtract”; with a list of such scientific papers as I could find freely available.

Tenguia is the most southerly, terrestrial expression of La Cumbre Vieja volcano; there is (not surprisingly) evidence of an undersea extension. Cumbre Vieja translates as “Old Summit” but it’s actually the active volcano driving construction of the island. There is a Cumbre Nueva; which is a scarp formed by a lateral collapse. Old and new refer to reforestation, not volcanic activity:



Caldera de Taburiente and Barranco de las Angustias are the dominant features; south of which are Cumbre Nueva, then Cumbre Vieja…



Cumbre Vieja has had several historic eruptions, with activity also documented in: 1585, 1646, 1677, 1712, and 1949, there is also solid evidence for an eruption at some time ~1430-80.


Cumbre Vieja: Eruptions, by Carracedo.

To give this some context; the Canaries have also had semi- historical eruptions in Tenerife: ~1341, ~1390, ~1444, 1492, 1704, 1706 and 1909; Lanzarote: 1730-36 and 1824 and El Hierro (questionably/ submarine) 1793 and (of course) 2011-present day?

That gives an average of ~ 39 years between (recent) eruptions, at widely spaced locations; it’s nearly 500km from NE Lanzarote to SW El Hierro. All powered by a single hotspot; edge driven convection is one of the current explanations for this, other theories are available…

Teneguia was an early tourist volcano:


The active phase lasted from 26th October until 19th November; there were two fatalities; a local fisherman working nearby and a photographer taking pictures of a lava flow. The cause of death was asphyxiation in both cases. There was some damage and loss of property; but the island is estimated to have gained ~29 hectares of land, much of which is now used for banana growing… The huge shade houses can (just) be seen at the bottom of the satellite photograph.

Intense earthquakes (up to MMI 5) were reported by locals immediately prior to the eruption, there were some quakes recorded during the eruption and a few more after; the last in the series was on 8/12/71. There is precious little in the IGN catalogue and no depths or magnitudes calculated…This is presumably due to lack of instrumentation; it’s hard to believe that an eruption of this scale had only 40 associated earthquakes. I generated an AVCAN map; but it showed only three points; ~30 EQs at Fuencaliente, a few at Los Llanos and one at El Paso.

Interestingly, given the quantum leap in seismic technology/ interpretation; La Palma has been virtually aseismic (I counted 4 in the IGN catalogue) since 1971…

During the eruption:


The Teneguia Tiger Team; sorry but I don’t know who is who…The main rift is fountaining in the background; the cone structure is entirely new, built by the eruption.

The eruption itself was extensively documented/ interpreted by The 3Ts; captained by Jose Maria Fuster Casas. Their morphology paper is the only article I’ve been able to find from: Volumen Teneguia, 1974. Estudios Geologicos (Volumen Especial), 85pgs.

A quick summary:

On 26th October, two eruptive centres opened at either end of a 300m long EW rift; producing spectacular strombolian lava fountains, they continued to emit lava virtually throughout…

Later, starting on 8th November;  4 smaller vents opened at the base of the new cone; of these, 3 went on to emit lava, also in a strombolian style:



The eruption has been classified as a schtrombolian type; but like the 1677, Fuencaliente eruption of Cumbre Vieja, (and others; including the 1949 multiple eruption) the emissions were more explosive at the upper vents and more effusive at the lower ones…

Teneguia was an impressive piece of mountain building, the main cone rises 100m above the pre- eruptive surface, the total erupted volume was ~40 million m^3, the lava flows have an average depth of ~12m and ~29 hectares of land was gained from the sea. All this in less than a month:



Teneguia’s lava consisted of basanites and tephrites; emitted in the form of lapilli, scoria/ lava-bombs and flows… This is a hand- sample of pumice; collected from near the path, halfway to the summit:


“All very interesting” I hear you mutter, “but it’s old news…”

Disclaimer 1: Please , there is no cause for panic at this time; remember we are talking geology here… Three of the papers referenced below discuss the following; in sensible, sober, scientific detail…

Some of the scientists who worked on the monitoring paper (see references) stated the folowing:

La Cumbre Vieja would collapse at the next eruption, which could happen at any time. They wildly exagerated the tsunami risk; saying that waves 25m high would reach the east coast of America in a few hours!!! 

The press quite naturally went to town…

However, their own scientific paper concluded that movements detected were within the margin of error for the system they used…

I was going to leave this issue to one side; (I didn’t want the tsunami freaks showing up) until Lizzie pointed out that the article “fizzled out” around basanites and tephrites…

2012ers and scientists talking to the media aside… Does La Palma have the potential for a substantial landslide/ collapse?  Remember La Cumbre Nueva? The black and white bathymetry above shows the debris avalanche quite well…

There is rifting along the summit ridge of Cumbre Vieja; new fissures and faults (up to 4 meters wide) opened during the 1949 eruption.

One can “join the dots” of cones along the ridge, so maybe some of these eruptions also produced fissures/ faults/ rifting…

Note that Teneguia did not noticably affect the situation; most likely because it was too far south, too low down and not on or near the very steep crest. The 1949 vents are close to the summit ridge at the far northerly end of Cumbre Vieja.

My amateur opinion: Other eruptions of La Cumbre Vieja will have contributed to rifting. (This would fit with the “general” theories of Canary Islands evolution.)

Please note my comment above: There have only been 4 EQs under La Palma since 1971; if the flank was moving and a landslide even remotely imminent, we should have some seismic indications…

Carracedo and others have done some work on this:

From Carracedo’s book, 2008:

“it is evident that if the western flank of Cumbre Vieja were detached and sliding, there should be observable ground cracks, seismicity and land deformation.”

“None of the above can be observed on La Palma.”

“There is no evidence whatever that the 1949 fractures are deep, nor is there any evidence for a detached block in danger of subsiding into the ocean.”

From Carracedo’s paper; below, 1999:

“lack of seimicity in the present inter-eruptive period indicates that the detachment; if present, is only activated by the intrusion of magma into the upper part of the volcano.”

I will of course be watching the GPS and seismograms closely if Cumbre Vieja erupts… As will the experts, the authorities and our old friends PEVOLCA.

To be very clear: (sorry regulars) The western flank is not at imminent risk of collapse.

Disclaimer 2: The author is an amateur journalist, and has absolutely no qualifications as a geologist… Please refer to the relevant government authority if you are at all worried about anything written above x

Schteve x

With thanks as ever to Lizzie x


Relevent Government Authority and EQ data:


Structure of La Palma using a 3d gravity inversion method; this is highly technical, but the pictures are interesting; (one for Geolurking?):


Carracedo et al on the 1677 eruption just up the (steep) hill from Teneguia; this reinterprets contemporaneous accounts in light of the geologic evidence:


The 1949 eruption:


Morphology of the 1971 eruption, by scientists who were there. Free; but you do have to download:


Carracedo et al on land slides and the evolution of La Palma and El Hierro, 1999:


Carracedo et al on the recent evolution of the Cumbre Vieja Volcano and the potential collapse:


Interesting work on monitoring of the potential collapse; authored in part by the scaremongers, 1999:


For more on edge driven convection and visiting Teneguia; see:



As ever; I have well thumbed copies of:

Carracedo’s Los Volcanes De Las Islas Canarias IV (ISBN 9788472071902) this particular edition has Spanish/ English/ Schpanglish text side by side by side; highly recommended…


Gates’ and Ritchie’s Encyclopedia of Earthquakes and Volcanoes (ISBN 0816063028) Carl would surely vouch for this one…

Right next to the clunkputer…

95 thoughts on “Teneguia: Technicalities and Context.

  1. Followup to my ‘fishbones’ (I like it!) Tongariro drum post, I’ve found a trace for a new Tongariro drum – KRVZ, probably the closest to the action on the north side. To my knowledge it isn’t linked from anywhere, but by manipulating the URL I was able to get it:

  2. Thank you, Schteve.

    Have you asked IGN direct for the EQ information for La Palma? They may have something but just not updated the database that we can access via their website.

    • Hi Karenz,
      You are most welcome,
      I haven’t asked directly and maybe they do have more than they are making public,
      but I think that what is in the catalogue is what was recorded.
      I don’t think that they are hiding anything… There are 123ish EQs listed for La Palma since 1370… I honestly think that is all they have records of…
      Despite the much discussed technical skew; I really believe that there have been only 4 EQs at La Palma since 1971… Just part of the Canaries enigma 🙂

      • I didn’t think that IGN were hiding anything but if there was uncertainty over the quality of the records they may not publish them.

  3. I recently saw a publicity for “Dior Homme”. The guy on the poster looked a bit unconfortable. Hm. The I read it from the right to the left. Emmohroid. Aaaah, well that explains quite a lot of the look of his tortured face…
    Sort of OT, although it indirectly has to do with some kind of “crater” if you’re open minded enough and have a blooming fantasy…

    • Looking at the collection of images on Google for “Dior Homme”… do they have a fascination with skinny punks or what? I seriously doubt any of those guys would last very long in a warehouse loading dock or on a construction job site. Of course they would be really easy to tend if you gave them a chipping hammer and dropped them over the side in a harness and working plank. If they slip and fall, just hoist them back up to it. They aren’t that large.

        • OT too- had the pleasure of being good friends with the first Female Hot Shot
          firefighter in the Forest Service-she passed the Test for the males.Even to day at
          50 something I don’t think any of those emaciated males could even keep up with her..
          Let alone pick up her pulaski…

  4. If anyone thinks that Schteve is being a bit sensitive about the landslide caveats and disclaimers… the action is understandable. Doomers go nuts over La Palma. Dunno why.

    Until Bob started fidgeting, I never had heard of El Golfo, El Julan, La Playas or the failed San Andreas slides of El Hierro. They seem to never get a mention. You also don’t hear much about Hilina Pali in Hawaii. It is an active landslide scarp that occasionally sees part of the island drop further and further into the sea. The last large movement was in November of 1975 when a Mag 7.2 quake caused some parts of the slump to suddenly drop by 2 to 3 meters.



    This isn’t abnormal for Hawaii either. A few million years ago, 244 km³ of Oahu took off on a 100 km joy ride and left the Nuuanu slide scarp. You can find that chunk of dirt in the form of the Tuscaloosa sea mount at 22.046489°N – 157.128033°W.

    You also don’t see Doomers allowing for the radial to planar transition on tsunami wave fronts. Not all tsunamis are created equal. While the thing is in radial mode, it looses power with distance. It is not until a few wavelengths out that the wave becomes somewhat stable and manages to retain much of it’s power as it travels in a planar fashion.

    Then… there is also the matter of size. The Japanese tsunami involved a displacement of water equivalent to about the entire volume of the above water volume the island of El Hierro… to about twice that. Anything less than plunging the entire island underwater is going to make a tsunami significantly smaller than the Japanese event.

    Doomers, ya got to love em. They will do or believe anything in order to freak out.

    Really good article Schteve!

    Residual fiddling around.

    A good site (data wise) with a really horrible background on Hawaiian landslide and slumps.


    * a background should not be so intrusive that it makes the text hard to read.

    • There was a discovery channel special about 5-10 years back that said a 100 foot tsunami would strike the entire east coast of the USA if la palma collapses. I was still in high school then, but even then it seemed like bogus, it just didn’t seem physically possible for a wave not to disperse after that long of an event. Their only comparison was using Lituya Bay, which is like comparing a bathtub to the great lakes.

      So if you want to know why the doomers are obsessed with this, it’s another case of bad discovery channel doom and gloom, and people not caring to realize that like Yellowstone, this isn’t the only area in the world that an event of this nature can happen (although it still wouldn’t be anything of a big deal).

    • Thanks for chipping in Geolurking, I don’t know ifn you got a preview in the end?
      I remember a plot of yours which suggested that a lateral collapse of El Hierro would affect the eastern seaboard like a pebble dropped into the far side of a fishin’ lake would affect the duckhouse 😀
      I know I added extra disclaimers, but I really don’t want this schplashed across the dailyfail website 🙂
      Did you notice how Carracedo’s tune changed from the 1999 paper to the 2008 book? They are quotes in isolation I know; but I think they are “fair” selections…

    • Thank you, Lurk, and Shteve for good posts and opinion this Am. I read somewhere that the max height of Tsunamis can’t be much over 30 meters due to the physics as described by Lurk. One exception would be Meteor strikes if the rock was large,,,,

      • Well, discounting the bathtub effects when it’s a tight body of water…

        As for actual max height, I don’t think that I’ve actually stated a max. You are always going to have the odd instance where a bay or bathemetry can focus the wave.

        We had an interstate bridge taken out by Hurricane Ivan in 2004, water lifted the concrete sections off of the pillars. This was due to the reflected wave action and storm surge. The bridge was about 20 to 25 feet off of the water… and almost 20 km away from the Gulf of Mexico shoreline.

        That double headed yellow arrow line is supposed to be labeled “19.7 km”

  5. Fifteen Hundred Earthquakes in November
    A total of 1,500 earthquakes hit in Iceland last month. According to data from the Icelandic Met Office, the most seismic activity—or a total of 750 earthquakes—occurred in Eyjafjörður, which was also the location of the strongest earthquake, of a magnitude 3.8, mbl.is reports.
    In late November, a minor glacial outburst flood was reported in Grímsvötn volcano in Vatnajökull glacier. GPS data shows that the ice level had decreased, a strong indication that a flood had started. The flood reached its peak on November 26.
    A glacial outburst isn’t necessarily an indication of an upcoming eruption. http://www.icelandreview.com/icelandreview/daily_news/Fifteen_Hundred_Earthquakes_in_November_0_396113.news.aspx

  6. Good Article Shteve ,Thank you. It makes interesting reading.
    The The “dead Zone” in Iceland is looking busy. Mjoaskard especially in the south area. http://hraun.vedur.is/ja/oroi/mjo.gif
    Haukadalur has nice regular patterns again. Traffic? Some sort of building work? I don’t go with wind. it’s to “daily ” and regular.http://hraun.vedur.is/ja/oroi/hau.gif
    To the west of South West of Hekla Sauber also is busy. . I think the there is plenty of rifting movement at the moment . Just a reminder that this rifting does not mean there is a volcanic eruption imminent. (This for those who are worried about Xmas air travel in Europe!). However I am not a geologist, but I learned enough now about volcanoes to say absolutely that nobody really knows when or where the next Icelandic eruption will take place! 😀

      • Haukadalur, hau, is really human activity. Notice the daily increase, and goes back to calm at night. And also activity only occurs in working days. Weekend is dead calm.

        But mjo seems a bit more restless. It could be Hekla, or maybe just the increase earthquake activity in recent days. I wouldn’t worry.

        But I expect Hekla to erupt this winter. I need some winter fun.

    • ehm .. how often did you integrate the words “scaremongerer” and “2012” in your post … hust (coughs) , räusper (clears her throat) … 😯

      • That’s one of the things I like best about Volcanocafe… Even when we are taking the pxxs, it’s evidence based 😀

    • Really interesting post Schteve, it is a fascinating Island and this post gives me a lot more to learn when I read all the links.

      • Hi Newby, thanks, La Palma is quite something; the links are indeed worth a look…
        I hope you are feeling better, so nice to hear from you.
        How are things in Bognor? We have (so far) avoided the worst of the weather in Brighton… x

  7. First thing:
    I am almost finished writting a 3-part post called “A TOUR OF ICELANDIC VOLCANOES”. This is an idea some people suggested quite a while ago. I think you will like it 🙂 It should be coming soon. Spica, check the mailbox 🙂

    Second thing, SISZ:
    there is a tiny swarm currently taking place at Hestfjall. It started with a 2.0 quake during the night, I was sleeping but living only 5km from this mountain, I would probably feel it if this was not during the night. It was near this spot where a M6 quake occurred in 2000. It is a well known major fault. But since large quake was recent, this tiny swarm means nothing.

    • Basically, the post I am writting is a tour of all active Icelandic volcanoes. Including facts about the lesser known volcanoes, such as when were they last active, how is their shape, etc… its fun stuff.

  8. To those that like astronomy, tonight there is a meteor shower, called Geminids. Just look eastwards to the sky and wait some time… Best from a dark location.

    • I will be out on my frozen decking… however there is a fron coming in with rain ( preceeded by snow here) so I hope I can see them before the sky clouds over.

    • I was looking forward to seeing these – we’ve had clear and very cold nights all week – and then just as the sun set this evening the clouds and rain rolled in! Typical! 🙂

  9. The fishbones are back…

    But compare and contrast that drum with this one, which is unlinked and unpublished, but is in the North side of Tongariro, much closer to where the action is:

  10. So far I have seen around 20-30 meteors tonight, in only about a few minutes outside. The rate is around 2 or 3 per minute. I will go now, for a little bit more outside, just to check a few dozen more. Its a really clear and starlit sky outside (probably because its new moon)

      • Yes that is a pity. Weather is pretty clear here. But cold.

        I came 10min from outside, I am really frozen now. Nose frostbite. Its about -7ºC and a strong north wind just picking up speed now.

        I saw about 20 meteors, some nicely bright. They usually come in groups of 2 or 3 in a few seconds.

        There is also northern light, but not very bright, to the north. Auroral activity is recently really low (blame very weak solar maximum, if we can even call it that way).

      • I have just seen my very first meteor in the sky tonight…how beautiful was that! I thought it was a shooting star, but then I saw Irpsits comment and my husband said that on the Spanish news they had said to look out for meteorites yesterday and today…..There is quite a bit of scattered cloud outside tonight, but I am going out again to see if I can see some more…absolutely awesome! .

      • On October 11, 1983, during a search for moving objects amidst the data gathered by the Infrared Astronomical Satellite (IRAS), S. Green and J. K. Davies found a rapidly moving asteroid in Draco. The next evening, C. Kowal (Palomar Observatory, California, USA) confirmed the body by photographing it with the 48-inch Schmidt telescope. The asteroid received the preliminary designation 1983 TB. As early orbital calculations were being made, the International Astronomical Union Circular for October 25, 1983, relayed the opinion of Whipple that this asteroid moved in an orbit almost identical to that of the Geminid meteor stream. Additional observations confirmed the link and the asteroid eventually received the permanent designation of 3200 Phaethon. The excitement of having found the parent body of the Geminid stream was almost dwarfed by another realization, this was the first time an asteroid had been definitely linked to a meteor shower and it subsequently serves as an important link between comets and meteor streams.


        3200 Phaethon is an Apollo asteroid. As such it is an Earth crosser since it’s orbit crosses ours. The period of the orbit is 523.586 days. This means that Phaethon gets pretty close every 18.4 years. By close, I mean that the orbits get close… but not necessarily close enough for them to interact gravitationally.

        Using the JPL Nasa’s data on 3200 Phaethon, it never gets closer than about 2,963,433,815 km (2093-Dec-14 10:52) out to about the year 2199.

        So.. no real doom there.


  11. well now I am in overload, just been outside, the cloud has cleared, as it does very quickly in Canary Islands..the sky is an amazing picutre of beautiful silver meteors overhead…not just in ones and twos, but some are in lines of four…this is one the most beautiful things I have ever seen,…gosh….I am lost for words – just wish you could all be here to see this…bearing in mind that I am just went out in my night clothes and dressing gown…..I did not run the risk of catching frostbite outside.like Irpsit, although it is a bit chilly compared with gereral temperatures in Tenerife,,,,where I live because I am 600m above sea level, so 15 degrees celcius is not much of a problem really – I am so grateful to Irpsit for bringing my attention to this incredibe phenonem tonight.

    • Oh yes, that are images one wants to have in mind.
      Romantic minded woman, out on a terrace at night, looking into the sky, wearing “night clothes”…
      Uhm, ah yes, it’s about meteors… Sorry… Got my attention caught by other “details” of the scene…
      First we have Diana with her shower-stories and Wellies fantasies that has burned pictures in my tortured mind that will last until my end. Now you start playing that game too? If you girls go on like that volcanocafé will not be known for volcanoholism, but for everything that comes right before the definition of p.rn! Holy sons of the inter-/suprastellar powers united!

    • Hi Debbie, I am glad that you saw the meteor shower 🙂
      By the way its every 12 or 13th December, every year (its called Geminids). Also around 13th August there is another meteor shower (Perseids). And in November there are the Leonids, which often are not that special but on rare ocasions are fantastic. There are a few more meteor shower throughout the year.

    • Overcast in southern England (and now pouring with rain again) but apparently it was clear in northern England – Northumbria was mentioned – and they had great views with over 60 an hour being counted. I’ve often seen the Perseids so can’t really complain (much!) 🙂

  12. Friday
    14.12.2012 11:25:05 65.043 -16.469 19.7 km 1.9 99.0 6.3 km SW of Herðubreiðartögl
    14.12.2012 11:25:00 65.050 -16.468 18.4 km 1.0 99.0 5.7 km SW of Herðubreiðartögl
    14.12.2012 11:24:00 65.059 -16.437 22.8 km 1.5 99.0 4.0 km SW of Herðubreiðartögl
    14.12.2012 11:09:51 65.041 -16.444 22.8 km 0.7 99.0 5.9 km SSW of Herðubreiðartögl

  13. Thanks Schteve – really nice, thought-provoking article to give a nice welcome back home. Lots of reading matter there too!
    I had a little Google-about when you did your last Teneguia post and found this link – didn’t post it then because I didn’t want to tread on the toes of your follow-up.
    Don’t know how accurate it is, but it’s a cute way of looking at an eruption:

    • Interesting. But I don’t think this is the only place to find rhyolite at ocean spreading ridges.

      In Iceland, which is located in the middle of a such, the MAR, there are lots of volcanoes containing rhyolite, the biggest known areas for that being Torfajökull, Lón and Borgarfjördur Eystri.

      Also in 2007, scientists discovered a big caldera containing central volcano out on Reykjanes Ridge. http://news.nationalgeographic.com/news/2008/04/080422-iceland-volcano.html As far as I could get, there has not yet been carried out research re. the petrology of the volcano, but compairing it to volcanoes on Iceland mainland – and it was eg. compaired to Krafla volcano – rhyolite could be expected among others. Around Krafla, you don’t only find basalt (in the fissure system), but also rhyolite, eg. in the lava domes Leirhnjúkur and Námafjall.

      This is up on the summet of Námafjall, view direction north. In the background at yr. right: Krafla central volcano with the Krafla power station (steam cloud) in front, at yr. left side: the mountain chain of Kinnarfjöll on the western side of Skjálfandi bay (which is covered up by the mountains in the middle ground, all of them part of Krafla volcanic system).

  14. I suspect someone has found this already – haven’t had time to look back through all the comments and apologies if it’s already been linked – BUT … here’s a nice 3-minute video from Tolbachik (plus a few glimpses of an Mi-8 helicopter to make me doubly happy!)

    • Sorry, wrote the email in German. 😳

      There are some photos to use as you like. And I could perhaps deliver one or more posts on some spots in Iceland. Perhaps Irpsit could do an overview (perhaps sorted after regions). 🙂

  15. Apropos Iceland: There is a small swarm (up to magn. 3) going on at Kolbeinsey. Hopefully, the island won’t be destroyed by an undersea eruption. Iceland needs it. 😉

  16. Bárdarbunga is also rather lively again, my guess is Hamarinn. http://hraun.vedur.is/ja/oroi/dyn.gif For comparison, GPS re. Vatnajökull: http://hraun.vedur.is/ja/gps/samsaeri/vat.html Nothing new at Grímsfjall, I think: http://hraun.vedur.is/ja/oroi/grf.gif

    But there is still / again activity at Askja: http://hraun.vedur.is/ja/oroi/ask.gif and at GIL in Öxarfjördur region: http://hraun.vedur.is/ja/oroi/ask.gif

    Godabunga SIL is still out of order, but there seems not a lot of activity around Mýrdalsjökull at the moment.

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