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.

UKVIGGEN


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.

Spica

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

  1. Blame me for the religious bit. I was just slamming the idea of having one group shoving their belief system over another group.

    No one was eviscerated, no one was parboiled. (and I didn’t get to the other secular religion; Global Warming.)

    On the plus side, it did give the opportunity for that to air out. It’s hard to look at what we look at… and not try to connect that to whatever our belief system is.

    To all who were offended or uncomfortable I apologize.

    (unless you are one of the pushy people, in which case, pack sand)

    The downside is that it didn’t work. Every other time I have brought up philosophical topics, Carl has appeared.

    Bummer.

    Time to Drive.

          • These be “1” and “0” ? (but do not know which knows or not). Neither should be used in discuss politics, religion or Global h(w)arming.
            *hi* *waves to crowd and the regulars*
            Noticed recent eruptions (and thanks for updates on these).
            IMO has lifted uncertainty phase on Grimsvötn Glacial Run (no volcanic activity following, doh) but the Quake warning is still in force in the North (forcasting up o 6,8 R on Husavik or along TFZ). Awful slow-reader them last weeks and not read up on all, but noticed Laki is not forgotten, so do not know if anything has been discussed after that. Also Hekla is quiet. Likely will remain so for rest of 2012, likely so also be Katla.

  2. Again I was remiss. Very good post, Ukviggen. Simple, clear, to the point. I’ve visited the cave also but at the time I was not so much on the volcaholic side of the Force so I probably missed some parts.
    Again, very valuable post. No too technical and you learn things.

  3. “The second was also a 1990s top-rated, psychological TV thriller”

    Twin peaks springs to mind don’t know if/how it relates to volcanoes thoug

  4. Excellent post Ukviggen!! All the more so because I have been there but, like dfm, it was before my volcano addiction kicked in big time.. in fact Lanzarote may have been a trigger to it reawakening at all!

    • Totally agree with Bruce, I loved this excellent post Ukviggen….nice and to the point and interesting……I too have been to Lanzarote, but some 18 years ago.. My husband is from Icod de Los Vinos in Tenerife, which has, I think, the 5th largest lava tube in the world at 17km long….although I live in Tenerife, I have to admit, that I have absolutely no desire whatsoever to go into that tunnel !!

  5. First try on Alans evil riddle: Boltwoodite

    “A hydrated potassium uranyl silicate mineral with formula HK(UO2)(SiO4)·1.5(H2O). It is formed from the oxidation and alteration of primary uranium ores. It takes the form of a crust on some sandstones that bear uranium. These crusts tend to be yellowish with a silky or vitreous luster.”
    “It was first described in 1956 for an occurrence in Pick’s Delta Mine, Delta, San Rafael District (San Rafael Swell), Emery County, Utah, USA.[2] It is named after Bertram Boltwood (1870–1927) an American pioneer of radiochemistry.
    Boltwoodite occurs as secondary silicate alteration crusts surrounding uraninite and as fracture fillings. It is found in pegmatites and sandstone uranium deposits of the Colorado Plateau-type. It occurs associated with uraninite, becquerelite, fourmarierite, phosphouranylite, gypsum and fluorite.” http://en.wikipedia.org/wiki/Boltwoodite

    Composition (http://webmineral.com/data/Boltwoodite.shtml):
    Potassium 9.11 % K
    Uranium 55.45 % U
    Silicon 6.54 % Si
    Hydrogen 0.94 % H
    Oxygen 27.96 % O

    • “Dead straight”, do not know what this exactly means! And that is one of the great effects of this excellent riddles: curiosity being triggered; an urge to find the right answer.
      My guess is that “dead straight” means the same as “bolt upright”, which gives “bolt”. And a stick is mostly a wooden object, I guess. So – Boltwoodite.

  6. Another great post UKviggen – I really enjoy reading them – and you have just about convinced me to go to Lanzarote on holiday next summer!

  7. I don’t know if someone named this before: 4th volcanoe Star Peak, Vanuatu or Star Kikhpinych or Stary Shiveluch. 🙂

  8. My first try on a riddle 🙂
    Alans

    Amphibole (needle-like) asbestos groep. Amosite, crocidolite, tremolite, anthophyllite and actinolite
    http://en.wikipedia.org/wiki/Asbestos

    Actinolite is an amphibole silicate mineral with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2, and iron-rich ferro-actinolite, Ca2Fe5Si8O22(OH)2.
    The name actinolite is derived from the Greek word aktis (ἀκτίς), meaning “beam” or “ray”, because of the mineral’s fibrous nature.
    http://en.wikipedia.org/wiki/Actinolite
    The picture on wiki definately shows deadly straight sticky crystals 🙂 quite deadly infact, cause the tiny crystals damage your pulmonary alveoli.

    Crocidolite (fibrous riebeckite)

    Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na2Fe2+3Fe3+2Si8O22(OH)2. It crystallizes in the monoclinic system, usually as long prismatic crystals
    The fibrous forms of riebeckite are known as crocidolite and are one of the six recognised types of asbestos. Often referred to as blue asbestos, it is considered the most hazardous.
    Crocidolite asbestos was mined in South Africa, Bolivia and also at Wittenoom, Western Australia.
    http://en.wikipedia.org/wiki/Crocidolite#Crocidolite_.28fibrous_riebeckite.29

  9. Happy St Andrew’s Day to any Scots, part Scots, or any one who likes Scotland! 🙂 (I don’t know if I’ll get round to the riddles this weekend – toothache is not good for my concentration). 😦

  10. First try at Alan’s riddle (me head hurts after Suzie’s & schtumpted on hers at the moment 😆 ). On the principle that mud sticks:

    Mudstones made from clays and muds. http://en.wikipedia.org/wiki/Mudstone

    & possibly:

    Shale: “is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility.”
    Source: http://en.wikipedia.org/wiki/Shale

    Argillite: “is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are basically lithified muds and oozes. They contain variable amounts of silt-sized particles. The argillites grade into shale when the fissile layering typical of shale is developed. Another name for poorly lithified argillites is mudstone. These rocks, although variable in composition, are typically high in aluminium and silica with variable alkali and alkaline earth cations. The term pelitic or pelite is often applied to these sediments and rocks. Metamorphism of argillites produces slate, phyllite, and pelitic schist.” Source: http://en.wikipedia.org/wiki/Argillite

  11. There is some ash blowing around Tongariro now acc. to the cams. And taking into account the wind direction, I don’t think it comes from Tongariro itself. Something going on at Ruapehu? (Didn’t get into Ruapehu cams and didn’t want to insist neither.)

    • There is rain forecasted for this part of NZ, and on the zoomed cam, could be rain clouds. But on the other cam, there are clearly ash clouds up in the foreground sky and ash is blown around the Te Maari craters, perhaps reactivated. (I do know volcanic ash from own experience.)

  12. For some reason El Hierro has been visited by Salvamar Adhera + an aircraft today, both could be seen on http://www.localizatodo.com/mapa/ . The Salvamar stayed there for many hours and the aircraft which took off from Gran Canaria circled for some time north of the island. The actions do of course not have to be volcanism related.
    El Hierro 20121130 lokalizatodo

    • Lava seems to be still flowing. The glow was visible on the webcam for most of the Kamchatkan night, and the webcam now shows some billowing cloud in the vicinity of the fissures, suggesting that it is continuing. Hopefully the weather might clear a bit soon.

      Not that we should be surprised for this basalt flow to keep running for some time yet: the last one went on for 18 months.

  13. Last try at Alan’s riddle for tonight:

    A plaster sticks to you (a bandaid across the Pond). Plaster is made from gypsum, lime or cement. I guess you find it stuck to walls or ceilings ;?

    “Gypsum plaster (plaster of Paris): produced by heating gypsum to about 300°F (150 °C):
    CaSO4·2H2O + Heat → CaSO4·½H2O + 1½ H2O (released as steam). When the dry plaster powder is mixed with water, it re-forms into gypsum. The setting of unmodified plaster starts about 10 minutes after mixing and is complete in about 45 minutes; but not fully set for 72 hours. If plaster or gypsum is heated above 392°F (200°C), anhydrite is formed, which will also re-form as gypsum if mixed with water. A large gypsum deposit at Montmartre in Paris led gypsum plaster to be commonly known as “plaster of Paris”.”

    “Lime plaster is a mixture of calcium hydroxide and sand (or other inert fillers). Carbon dioxide in the atmosphere causes the plaster to set by transforming the calcium hydroxide into calcium carbonate (limestone). Whitewash is based on the same chemistry.”

    “Cement plaster is a mixture of suitable plaster, sand, portland cement and water which is normally applied to masonry interiors and exteriors to achieve a smooth surface. Interior surfaces sometimes receive a final layer of gypsum plaster. Walls constructed with stock bricks are normally plastered while face brick walls are not plastered. Various cement-based plasters are also used as proprietary spray fireproofing products. These usually use vermiculite as lightweight aggregate. Heavy versions of such plasters are also in use for exterior fireproofing, to protect LPG vessels, pipe bridges and vessel skirts.”

    All quotes taken from: http://en.wikipedia.org/wiki/Plaster

  14. Good evening everyone
    UPDATE for Name those Volcanoes Riddle –
    Dings/Points tomorrow but I can tell you that 2, 4 and 5 have been correctly identified – and there is a common link between them all!

  15. I just came to the blog after 2 days. Wow I missed such a heated discussion in one of the “forbidden” topics, religion! By “forbidden” topics I say religion, political opinions, fringe conspiracy theories, abortion, drugs, anything controversial 😉

    Well.. nothing interesting seems to be going on in Iceland at this moment… i am waiting tonight for an incoming solar storm, but so far no signs of northern lights

    • Hi Irpsit, lucky for you that you did not join in on the forbidden topics…I have to say again that I think Spica is doing an excellent job holding the fort while Carl is away…she is a very strong Dragon, and should be respected by all..I just remember that little fluffy dragon when she first started….well, she is no longer a dragon kitten, but a fully grown dragon lioness, so be careful to obey the rules.. 🙂

        • Or not…

          Instead of religious fundamentalism we now have democratic law processes. This works much better than saying the judge and jury is whatever is in your head, or inside the head of the religion’s head honcho.

          Laws are only as good as they are made though, and it would seem that fracking will require the making of new laws, if this quote from the link yesterday is anything to go by:

          ‘Energy companies are exempt from key provisions of environmental laws’

          Nature makes plenty of hazards by itself, and people on the whole choose not to raise livestock where the environment is already toxic. Preventing optional toxicity will need some kind of informed lobby group – like the food lobby – to try and get changes to the law made to protect people from harm arising from fracking, where risks are not yet fully understood, documented or preventable.

          • “Energy companies are exempt from key provisions of environmental laws’”

            Principally because the environmental laws were not designed to protect the environment, they were designed to control people.

            Hyper-Zealot environmentalists driven into a fury by those who have a deep rooted desired to be the center of attention or to impart some control over their fellow man.

            The formula is right out of Plato’s Republic if you can connect the dots. Machivelli did a bit of writing on the subject also. Most of the modern era Tyrants (as defined by Plato) use this mechanism to gain power.

            When it was stated that “… is the opiate of the masses” it wasn’t just ##### that he was talking about. Anything can be given enough importance to a group of people to have them take up arms and harm each other and to effect a directed modification to society… to have them do things that they would ordinarily think immoral. Crowds and groups do not operate by understanding knowlege and data… they operate on emotion.

            If you can direct that, you can make society do whatever you please.

            I may be skirting dangerously close to Godwin’s law in saying this, but Goebbels excelled at this practice.

    • “Silver Star Mountain is an extinct volcano in the southwestern Cascade Mountains in the U.S. state of Washington, named for the pattern of five prominent ridges that radiate from the summit in the shape of a star. The two peaks of the mountain dominate the horizon east of Vancouver, Washington.”
      http://en.wikipedia.org/wiki/Silver_Star_Mountain_(Skamania_County,_Washington)

      And the medal: “The Silver Star, referred to as the Silver Star Medal by the Navy and Marine Corps, is the third highest military decoration for valor that can be awarded to any person serving in any capacity with the United States Armed Forces. The medal is awarded for gallantry in action against an enemy of the United States.”
      “The Silver Star is a gold five-pointed star…..”
      http://en.wikipedia.org/wiki/Silver_Star

      • I looked for a supposed wrecked Cessna years ago in the Slver Star area wild country just mintues from the Portland or Vancouver Wa, area. We found the plane BTW parked at an airstrip. Seems the pilot had a girlfriend and didn’t want his wife to know. Made up
        some Bravo Sierra story about taking pictures of Slver Star..He didn’t return as soon
        as he said and she called the FAA who called the Civil Air Patrol and Air National Guard.
        and The US Coast Guard. It was an Air Guard Huey (UH-1)that landed at the airstrip…
        They weren’t happy.. Neither was the Cessna Driver .Nor his wife..

  16. Finally! After some days aimlessly wandering round http://www.emsd.ru I have found the place for recent Kliuchevskaya/Shiveluch quake activity (http://www.emsd.ru/ts/datareload.php?id=1). After pages of Cyrillic it’s all in English and is very interactive. You can specify the area (using the green circle) and the date range. There is a drop-down menu of data for each quake as well.

    So attached here is a screenshot showing the activity either side of the Tolbachik eruption (that is, within the green circle on the map). I guess it’s all self-explanatory, and shows well the pre-eruption quake swarm!

    • oh, veeeery nice! I wonder if that 30km stack of quakes under Kluischevskoi is related to Tolbachik in any way? That would be weird as they erupt totally different magmas. But otherwise there seems to be no precursor activity at depth. It was all shallow and went into action in about a day.

      • Going back month by month, there is a deeper swarm under Tolbachik in February 2012 but it’s not very pronounced. And another but shallower swarm in July. Not really very much compared to the vigour of the eruption and nothing like Eyjafjallajökull. That deep stack under Kluischevskoi by contrast it extremely persistent. Wonder if this is stoping above a deep chamber?

        • btw… not suggesting Kluichevskoi has anything to do with Tolbachik. They are obviously two distinct systems, just very close to each other!

  17. My try at Alan’s riddle
    Stichtite – Mg6Cr2CO3(OH)16-4H2O, Hydrated Magnesium Chromium Carbonate Hydroxide
    from near Dundas in Tasmania

  18. * sigh….

    Me stabbing at the dark… again.

    Specialty Minerals™ advertises adhesives with a quantity of Calcium Carbonate in order to augment and control the properties of the finished product. We know Calcium Carbonate from such things as limestone, chalk, marble and travertine. Pure forms can show up in Calcite, aragonite and vaterite.

    But straight? No… the actual adhesive is the carrying agent.


    Other “straight” things could be the barbs in asbestos. It comes form six natural sources:

    Serpentine → Chrysotile
    Amphibole → Amosite, crocidolite, tremolite, anthophyllite and actinolite.

    From WackiWikipedia: “They all have in common their eponymous, asbestiform habit: long (ca. 1:20 aspect ratio), thin fibrous crystals. ”

    So… there is “straight”.. and they can stick… if in the lungs you can wind up with Mesothelioma, and Asbestosis. And it can make you dead.

    In some parts of California, they occur naturally on the surface… and if disturbed they can provide an inhalation hazard.

    As for “sticking to you,” I remember quite well the itchiness of working with fiberglass insulation… dunno if asbestos had the same effect. My dad had about 6 bricks of it that were used to make a little oven for the soldering irons when he did gutter work. That stuff is amazing in it’s heat shielding capability. In fact, some of the first ablative shielding used in re-entry capsules contained asbestos. I don’t think later versions ablative shielding contained it… no one had the slightest care about the ablative shielding on the decks under the missile launchers. It was there so the birds wouldn’t burn a hole in the deck when they launched. (I’ve seen them strip steel completely bare of all paint and rust, leaving a clean matte finish. They are also pretty good at melting all the metal netting off of a Stokes Stretcher. Seems that the medical department didn’t do their part of the pre-fire exercise check list and left the stretcher hanging on the bulkhead… and that was just the exhaust wash from around the side of the missile house)

    Again.. stabbing at the dark.

    • At about 550–750 °C, Chrysotile (serpentine) deydrates into → Forsterite + silica + water

      Forsterite melts at about 1890°C, silica melts at about 1600-1725 °C.

  19. There have been two 2.2 quakes under El Hierro on Wednesday and Thursday. Nothing special in itself. But what do you think about the depths? The one on Wednesday at a depth of 22 km, the one on Thursday at a depth of 9 km. Could there be a reactivation of a deep feeder system under the island? http://www.diarioelhierro.com/ (“ESPECIAL CRISIS SÍSMICA – 30/11/2012 (10:10 horas) El Hierro registra dos seísmos superiores a 2 grados”).

    • Anybody happen to know what the actual geothermal gradient is on El Hierro?

      I went looking for it a while back and the closest estimate was for a drill hole several hundred km to the South East.

      • They were taking measurements of the heat/temp at Taranasoga, back when Bob was active, I recall a gauge being lowered into the vent some way.

        Not sure who ‘they’ was though.

  20. Alan’s riddle.
    Natural Tar, bitumin, pitch asphalt….whatever you want to call it. I will concentrate on the black, sticky stuff found in the largest tar Lake in the world at The pitch Lakes trinidad & Tobago. here’s what wiki says about this wierd geological oddity.
    “The origin of Pitch Lake is related to deep faults in connection with subduction under the Caribbean Plate related to Barbados Arc. The lake has not been studied extensively, but it is believed that the lake is at the intersection of two faults, which allows oil from a deep deposit to be forced up.[3] The lighter elements in the oil evaporated, leaving behind the heavier asphalt. Bacterial action on the asphalt at low pressures creates petroleum in asphalt. The researchers indicated that extremophiles inhabited the asphalt lake in populations ranging between 106 to 107 cells/gram.[1][4] Pitch Lake is one of several natural asphalt lakes in the world. The La Brea Tar Pits (Los Angeles), McKittrick Tar Pits (McKittrick) and Carpinteria Tar Pits (Carpinteria) are all in the US state of California. Lake Guanoco is in the Republic of Venezuela.”

    There is a suggestion that Bitumin is formed by
    Serpentinization http://www.everythingselectric.com/forum/index.php?topic=76.0
    Dead straight? Natural Bitumin was used in some methods of Mummification. The word Mummy comes from Persian “mumiai” (pitch, asphalt). The custom of preserving the dead by an elaborate process of embalming, with attendant rites, practiced by the Egyptians and other ancient peoples such as the Incas in Peru.

  21. And to make up for the flailex that I caused in the last thread….

    View North

    View East

    And something for the plotters… a bit of page disassembly and digesting it into a usable format, extracted from the page linked in ukviggen’s December 1, 2012 at 00:37 post.

    It’s a spreadsheet, don’t download it unless you know what to do with it.

    https://volcanocafe.files.wordpress.com/2012/12/tolbachik1.xlsx

    Year Fraction, Excel Date, Date, Time, Lat, Lon, Depth (km), Some value that I don’t know the meaning of, Magnitude.

    It covers 8085 events from 1 Dec 2011 to 30 Nov 2012.

    Yeah… it’s not shown on the page, unless you know how to dig it out. 😀

    Note: The Spreadsheet is subject to deletion if VC needs the room later! By that time the data will be stale, so save it locally if you want to hang on to it.

    • Excellent! That was quick. The view north is especially illuminating.

      Do you mean the Ks value? It’s defined on the website as:
      Ks – class from the amplitude of S-wave, defined by Fedotov S.A.
      Ml – magnitude using the formula Ml=Ks*0.5-0.75

    • Thank you for the post ukviggen, you keep amazing me!

      Leeched on that well prepared data gift 🙂 Thank you GL!

      Have been busy lately and now I find it hard to decide what to plot first ;-).

      This animation shows all earthquakes in central Kamchatka above like 2-3 magnitude provided by IRIS (http://www.iris.edu/servlet/eventserver/map.do table) color coded in gold and the events going back one year color coded in cold to warm (covering a partial area). Some earthquakes from IRIS presumably have a default depth of 33 km asigned to.
      The big glob at 30 km below Kliuchevsko is very prominent, then there is the second area of activity south of the current eruption site at Tolbatchik as ukviggen already said above. A straight path of earthquakes ascending at shallow angle towards Shiveluch in the north also point in the general direction of the glob (but too far away to be connected?).

      Here is the result:

  22. Just a guess on volcano six before I leave. The coordinates 42.108N, 169.160E lead me to the Emperor Seamount chain, but I cannot find anything with exactly this coordinates. Maybe S instead of N ow W instead of E. Or something completely different.

    • Yomei was the closest seamount that I could find but not close enough unless Suzie is using a completely different map 😉

  23. Good morning everyone
    Dings/points have been given for the first five volcanoes in last nights’ riddle – well done UKviggen, Stoneyard, DebbieZ, Inge B, Alison and Sissel
    Hmmm no. 6? HINTS –
    Well, the common link is that they are all in the USA and you don’t need a map in order to solve the clue!
    I am off to football (COYR) and the cinema so I guess spica will keep an eye on the riddle for the rest of the day!

    • My second point! I don’t usually get chance to try the riddles as I go to work before they are posted and are usually solved by the time I get home.

      • Yeehaw too!

        @Kilgharrah – so who are your ‘Rs’?
        I’m off to watch my ‘Rs’ play some other ‘Rs’. So why am I sitting here on VC? Late kick-off!

        • My Rs are the mighty …… Southampton! And we lost away to Liverpool but only by one goal so I guess I should not be too sad!

          • Aah! So my R’s are playing your R’s next weekend (sadly I’m away as I usually go to that). Ooh, now let me try and remember what happened last time we met …!!

            Bad luck for today. We experienced a seven-goal first-half, and a no-goal second half. Very weird game which we lost, of course. On the basis that football is up there with r**igion for getting folks all riled up I’ll shut up now! May the best R’s win next Saturday 🙂

      • Hi
        OMG You’re right the ding/point goes to Debbie not Karen eeeke – I was in a hurry (well that’s my excuse!) I will change it now!

  24. @ Inge
    Vatnajökull is on its way. However I have to cut it by year as there are more than 7000 events (!) since 2010. First part will be 2012 (2000 + events)

    • Note: .. the view is from the NE looking to the SW.

      The stack is right on the edge of the Icelandic Shelf, and in a region that may have turbulent outwash features on the sea floor. (not that it’s that, it’s just something else there)

      The stack is still near the spine of the Icelandic Large Igneous Province that runs out past the Faroe Islands.

      Iceland’s stucture shows a phenomena called ridge jumps. Thats where one set will shut down and a new line will show up form in a different location. The Grimsvoton to Katla line is an example of this, eventually, the MAR will connect via Vestmannaeyjar rather than via Reykjanes… but that might be a few million years for it to complete.

      This stack that you see, could be the precursor to the follow on activity after that.

      • thanks Lurking, it’s because the intensityof the EQs is rather large and I had not noticed this swarm before. So no name for a specific volcano ?
        This run is gonna take some time (up to tomorrow, 1180/2089 right now), when it’s finished i’ll turn to Tobalchik

    • Do you mean the stack out under the sea? There were sometimes quakes in the sea south of Iceland, esp. south of the town of Höfn on the Icelandic shelf.

      There is also talk about a possible rift jump in the future in Iceland again as GeoLurking says. As there has – as far as I know – always been a parallel line of volcanoes with a transfer zone in between also in the past, it could be that the next eastern activity line would be from Snaefell down to Esjufjöll or Höfn, and the western one from Askja over Grímsvötn down to Mýrdalsjökull or so.

      About 7 mill. years ago, the western rift zone was jumping from the Snaefellsnes – Vatnsnes-Zone over to today’s Reykjanes-Langjökull-volcanic zone, see eg. http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=A0241365AH&q=iceland+%2B+rift+jump&uid=792324578&setcookie=yes

      • As far as I remember, we were once discussing these quakes here – some time ago, and ruminating about the possible existence of a seamount at the place, but didn’t find any evidence. I just found a very old text (from the 70s) by Kristjánsson, e.a. where they stated the sea bottom on the shelf would be more or less flat there, but they didn’t show a real bathymetry. And so I found some about the northern shelf. Does anybody know perhaps about a bathymetric study of the sea south of Vatnajökull (southeast Iceland)?

        A bit more literature on the jumping rift zones in Iceland: http://eee.rsmas.miami.edu/users/geodesy/articles/2005/Iceland2005.pdf 🙂

  25. @ Kilgharrah December 1, 2012 at 12:15 – I was so made up and so excited,,,,was about to say ….YEEHAWHAWHAWWW!!!!!!!!! YES, YES AND YES!!!!…Kick that ball into the back to the net!!!!!! ……after a whole year, DebbieZ finally managed to get a point on ” name that Volcano” …(well techically half a point, shared with Stoneyard)…..but you have given it to KarenZ.- KarenZ, help me here, how to a do a “smiley” big tear rolling down my cheeks – desolate crying face!

    • Ok been to gems, will try to express myself in smileys…first was 😯 = shock – second was 🙂 = sad , third was 😥 – = cry…knowing my luck this will not work…but here goes anyway! 🙂

      • Thanks KarenZ, I know you did, bless you! I was just kidding….. (although I will admit, I was soooo pleased with myself for getting something right for once, espcially with all you “amateur experts here).

      • Hi Kilgharrah, no worries,,,,it is just a bit of fun after all……I would much prefer to eat a large slice of apple pie……or even better, now we are in December, a lovely hot juicy mince pie…yummyummm….better start putting the christmas decorations up soon so that I have a good excuse to indulge myself in all christmassy foodstuffs… 🙂

    • OK, for what it is worth, I know that you are far too devious and evil for this to be anything I could ever come up with an answer for, however, I am going to be brave, and face the chance of total ridicule (it´s OK I can take it!) … I was.looking for something that would make your face dead straight and that would definitly stick on you…and came up with beauty face mask treatments…….Kaolinite is an ingredient that is used in some… it is a (taken from Wiki)¨:
      “clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra.[4] Rocks that are rich in kaolinite are known as kaolin or china clay….(I will be off to bed soon, so laugh at me when I have gone please 🙂

  26. Geolurking
    I am awfully sorry but i accidently deleted 2 of your files. Was not on intention, I am having computer and link problems.
    And wanted to upload a tinypic image by UKViggen because i think it is worth being stored.
    Did not wok, somehow i cannot upload images at the moment at least not from thins computer.
    Could you upload your image and the xls file again. Please

    • I dont really understand what is wrong with this computer, ( i got a new harddrive yesterday and since then quite some things do not work correctly. For example i cannot connect to gmail, i have absolutely no clue why.

    • I am also having link probs and so it looked to me as if i had uploaded the image 3 times and i tried to get rid of the extra versions. But instead, my upload had not worked at all. Dont know whats wrong. and just so you know, i have a bad flue and sometimes rather high fever.

    • Spica says:
      December 1, 2012 at 21:38 (Edit)

      Geolurking
      I am awfully sorry but i accidently deleted 2 of your files.

      Fixed.

      The image probably could have been left alone, WordPress seems to hang on to imagery even after it’s deleted, but the spreadsheet went poof.

      I re-uploaded it and fixed the link. In about a month it would be a good candidate for deletion anyway.

      • Nah, we use 700 Mb something of our 3GB. I want to keep it as colorfull ( pics) as possbily
        What we do once we ran out of storage space is beyond me.
        You say deleting files wont help, because wordpress hangs onto it. hm
        Do you have any idea what we could do?
        (((( I have not been uploading more microscopic images , just because of that)
        And thanks a lot for fixing my mistake.

        • Dunno how long the deleted imagery stays viable after it’s deleted. But when you delete an image, and re-upload it, WordPress tags the new image with a 1 or 2 if the image name matches a previous one… even if it has been deleted. I have no idea if it still goes against the Sites usage tally after that.

          The same thing applies to the spreadsheets.

          As for solutions… dunno.

          • Yeah , long time ago i uploaded some images to my testthingie and linked them from here and i was totally happy because they photos showed here. What took a while to figure out… they showed only for me, not for anyone else.

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