Alaid: Part 2 – rising from the sea and 2 riddles!

L. Kotenko

From a distance Alaid appears to be a regular stratovolcano, but its collapsed summit crater and flank cones (a crater row can just be seen at extreme right) make it more complex (© L. Kotenko via KVERT)

Alaid’s summit stands 2339 metres above sea level, making it the tallest volcano in the Kuril chain. It rises up from a sea bed that is around 750 metres deep, making its overall height in the region of 3000 metres – quite a giant. Its birth dates to around 40,000 to 50,000 years ago, and it is classed as a Somma-Vesuvius type stratovolcano, with a resurgent 250-metre cone having grown inside the partially collapsed central crater.

In a sparsely populated area with few written records Alaid’s history prior to the 20th century is little known, and even recent events have gone unnoticed or unconfirmed due to the remoteness of the location and the poor weather that can often shroud the summit for days on end. Alaid is known to have had mainly explosive eruptions from the summit crater in 1790-93, 1854, 1860 and 1894. The eruption of 1790-93 was considered a large event, and was given a VEI4 rating.

Alaid is noticeably different to other Kuril volcanoes, and not only on account of its large size. For a start, it lies behind the main island arc of volcanoes, while its magmas are predominantly high-aluminium, high-iron basalts, with very little evidence of more evolved andesites. Alaid’s nearest active sub-aerial neighbour is Ebeko, which is located around 37 km to the ESE on Paramushir island along the main arc. Ebeko is much younger, an active and typical subduction volcano producing andesites and andesitic basalts.

Alaid also has at least 36 parasitic cones on its flanks, including those underwater. Such features are rarely found on other Kuril volcanoes. Furthermore, the mineral traces in waters of the geothermal area that was created in the 1972 eruption are very different to those from geothermal areas in the main island arc.

Alaid has a baby!

Although the presence of large numbers of cones is evidence of a history of radial fissure and excentric vent activity, this was not observed until an eruption that began on 13th November 1933. The activity began underwater just off the east coast of the island and led to the creation of a new cone that rose from the sea just offshore. The eruption continued until August 1934, and left behind a new island that was soon joined to the shore by a narrow isthmus of volcanic sand. The new land was called Taketomi and today it clings to Alaid’s side, erosion having reduced the joining spit to a razorbacked sliver.

Taketomi 2

Taketomi was formed by an underwater flank eruption. The crater is joined to the shoreline by a narrow spit of sand (© R.V. Zigacheva via KVERT)

The Olympics eruption

Olympic 5

The four craters and lava delta formed by the 1972 eruption (© V.A. Rashidov/IVS DVO RAN via KVERT)

Alaid was quiet for the next few decades, but sprung into life again on 18th June 1972. Again this was a flank eruption, but this time in the northwest of the island. Four explosive vents (maars) opened up along a radial fissure, one of which measured around 500 metres in diameter. Lava issued mainly from the two lower vents and then ran to the sea, where it increased the island’s area through the formation of a lava delta that extended the coastline by about 300 metres at its maximum point. From one of the maars a cinder cone grew, eventually reaching a height of around 80 metres. Explosive activity ceased on 15th August and lava stopped flowing on 11th September. A crater row was left behind, named the Olimpiyskiy cones (the Munich Olympic Games were under way during the latter part of the eruption).

Olympic 2

During the 1972 Olimpiyskiy flank eruption lava flowed into the sea to extend the area of the island by about 1 square kilometre. Here the lava steams as it meets the sea, while the vents behind continue to smoke (© V.A. Podtabachny/IVS FED RAS via KVERT)

Thanks to Beeld en Geluid here is a short film (with Dutch narration) about the 1972 eruption, complete with a fox (the island’s largest inhabitant) and the obligatory crazy Russians walking around on hot lava.

Major eruption of 1981

In the early afternoon of 27th April 1981 Alaid exploded into its biggest eruption since the 1790-93 event. It began with a small steam plume, but explosive activity increased rapidly in magnitude to build a black ash column. The eruption further intensified the next day, and three large explosive blasts were recorded by microbarographs at Kushiro, 1250 km away to the southwest. Over the next two days a dense plume around 1900 km long was formed, the column reaching to an altitude of 13000 metres. On 1st May the main plume feed came to an end.

alaid-1981

In the initial stages of the eruption the ash cloud was reportedly too thick for aircraft to approach, but as soon as the plume settled into a more stable state geologists flew to the area
(© V.A. Podtabachny/IVS FED RAS via KVERT)

Ejected ash, comprising a pyroxene olivine basalt, fell over an area calculated as 150,000 km^2. On the island’s shore more than 30 cm accumulated, and small lahars formed as ash mixed with snow and ice. In the town of Severo-Kurilsk, 45 km away to the ESE on the island of Paramushir, residents heard the volcano’s roar and could see a glow by night. Soon the ash began falling, and up to 25 cm accumulated, leading to some disruption.

As the plume headed northeast, ash mixed with wet snow fell on the Kamchatkan town of Petropavlovsk at a distance of 300 km from Alaid, and ashfall was recorded as far away as the US military outpost of Shemya, 1200 km away in the Aleutian island chain.

022080

Another view shows how Alaid’s ash plume divided into a more diffuse lower altitude element, and a denser upper component (© V.A. Podtabachny/IVS FED RAS via KVERT)

On 29th April the wind changed direction to ESE, taking the plume out over the Pacific. Over the next days activity declined significantly, and ceased temporarily on the 7th. On the next day, however, Alaid produced another sizeable eruption column. The plume was not as large as that produced by the initial eruption, reaching only 400 km in length.

Further eruptive phases took place in the coming days, producing plumes of varying lengths. Activity was continuous from 15th to 27th May, at times the plume reaching nearly 600 km in length. By the time the eruption ended on 5th June it had pumped an estimated 5.5 x 10^8 cubic metres of tephra into the atmosphere.

NOAA

This view of the ash plume from the 1981 eruption was recorded by the NOAA 6 weather satellite (National Oceanic and Atmospheric Administration)

While the US NOAA 6 and Japanese GMS satellites provided some imagery of the eruption plume, when weather permitted, the 1981 eruption was also tracked by NASA’s then relatively new TOMS (Total Ozone Mapping Spectrometer) sensor. This was carried by the Nimbus-7 satellite and had gone ‘live’ on 31st October 1978, in time to provide data from the Mount St Helens, Krafla and Hekla eruptions in 1980. NASA was able to track the distribution of aerosols and the sulfur dioxide cloud from Alaid as it spread across North America in the days after the initial explosive event.

Page 1 copy

A daily sequence of TOMS imagery tracks high levels of sulfur dioxide from the 1981 eruption. There are two distinct SO2 clouds, one which tracks northeast and over Alaska and northern Canada, while a later cloud tracks east and largely dissipates over the Pacific Ocean (NASA)

Alaid’s faithful companion

On the surface, at least, Alaid stands alone, but appearances can be deceptive. In the decade following the 1981 eruption the Vladivostok-based Soviet research vessel Vulkanolog conducted a survey of the area, mapping the seabed’s profile and magnetism, and collecting dredged samples for analysis. The seas around Atlasov Island were of particular interest, particularly Alaid’s companion that lies hidden beneath the waters.

Page 1 copy

Topography/bathymetry of northern Kurils
(© KVERT, annotations by author)

Just to the northwest of Alaid stands another volcano, its summit submerged beneath the sea. Named Grigorieva, after geologist I. F. Grigoriev*, the submarine volcano’s peak is around 10 km distant from that of Alaid. Analysis of samples showed that Grigorieva’s rocks are similar to those of Alaid, although it is considered as a separate volcano in its own right, despite the fact that its base has merged with that of Alaid. With its peak at a depth of around 140 metres, it is quite likely that Grigorieva once breached the surface during the time of the most recent glacial maximum. Like its sub-aerial companion, Grigorieva has a high number – at least 13 – of extrusive lava domes on its slopes.

Much further to the northwest is the Lebedya (swan) bank, another raised area of seabed. It has been suggested that Alaid, Grigorieva and Lebedya could be related, representing a side-spur of volcanic activity that lies perpendicular to the main plate boundary that drives most Kuril activity.

  • Iosef Fedorovich Grigoriev was a geologist specialising in ore deposits who became a key figure in the dramatic rise in military industrial output during the Great Patriotic War (1941-45). At the end of hostilities he became the chief geologist leading the task of developing a uranium mining operation in Krasnoyarsk territory to provide fuel for the Soviet Union’s nascent nuclear weapons programme. On 31st March 1949 he was arrested, with other senior geologists, on the basis of untrue allegations that he had concealed details of uranium deposits. For years the official story held that he was tried, convicted and sentenced to the gulag, where he died in 1951. In fact, he died on 14th May 1949 while being transferred back to his cell following an interrogation session, just six weeks after his arrest. His honour and reputation were fully restored in 1954.

Recent activity

AA Ovsyannikov

During the April 1981 eruption a new cone grew in the summit crater, seen here in June as the eruption came to an end. In 1986 the cone partly collapsed – compare with later photos of the main crater (© A.A. Ovsyannikov/IVS FED RAS via KVERT)

Since 1981 Alaid has been restless. Small explosive eruptions at the summit crater have been recorded in March 1982, May 1986, December 1996 and August 1997. During the 1986 event much of the 60-metre high central scoria cone that had arisen in 1981 collapsed. There may have been other minor events, with some seismic and thermal evidence to suggest them, but nothing was actually seen, and high winds in the area have often produced readings that could be interpreted as volcanic tremor.

Last year the volcano again showed more than a glimmer of life. On 5th October a gas-steam plume containing some ash was noted rising several hundred metres from the summit, and similar episodes were recorded throughout the month. At the same time, snow on the mountain sides began to acquire a thin coating of ash deposits, and a small cinder cone was noted to have grown in the summit crater. Seismic activity was noted by KVERT in late November as ‘moderate’, with volcanic tremor rising to 18.7 mcm/s. From early December activity dropped off, and Alaid appears to have gone back to sleep. Its aviation status was reduced to green in January.

A Sokorenko

A fly-by of Alaid’s summit on 27th October 2012 showed fumarolic activity. The volcano showed signs of unrest into December (© A. Sokorenko/IVS FEB RAS via KVERT)

While this low-level activity appears to be quite normal for the volcano, the eruption of 1981 showed that Alaid has the potential to create considerable havoc to air traffic in the region. It is alive, ashy and explosive: definitely one to watch in the coming years!

UKViggen

Thanks to KVERT for permission to use images from the agency’s website (http://www.kscnet.ru/ivs/kvert/index_eng.php)

————————————————————————-

Update:

Alan C’s Evil Riddle:

My true dusky identity was hidden! My secret lies in my blackness! Confused?
What am I?
Who are my relatives?
Where can I be found?

Clue:

Pay an old Greek a visit! He may let the cat out of the bag!

————————————————————————-

Update #2:

NtV (Name that Volcano)Riddle

1 point for each volcano; RED HERRINGS now shown in bold!

No 1 Lethal lahars; Starry siblings; Satellites; Volcanic group;
No 2 – Mild vulcanian; Cargo Cult leader ‘residence’; Lava bombs; 1874; SOLVED .. Mount Yasur
No 3 – 1927 German Silent movie; Northern Europe; Legend of ill fated lovers; Two calderas;
No 4 – Flank fissure eruptions; c4 mile glacier; 1921; Emperor penguins; SOLVED .. Beerenberg

539 thoughts on “Alaid: Part 2 – rising from the sea and 2 riddles!

    • I also very much appreciated this follow-up on a volcano which seems to be a somewhat smaller brother to Etna, re. the felsic magma composition at a subduction zone and also the building of parasitic cones on rift zones. But a brother to El Hierro as well.

      Thank you, Ukviggen, for the excellent work. 🙂

  1. Nice one again UKViggen. It has made good reading for early morning and has gone well with Coffee #1. Thank you.
    Volcanic ash makes the world a far smaller place! I laughed at the comment about obligatory Russians Lava walking… erm! You get USA ones on National Geographic, British ones on BBC news. The fox? Well a survivor . A perfect example of species adaptation to harsh environments. A true opportunist. It was probably after the Lava walkers Picnic sandwiches :D.

    • I’m sure you’re right about the fox. Must have thought all his Christmases had come at once.

      Of course there are Brit and American lava-walkers, but I have heard they are only allowed to do so after a specialist consultant has been called in to conduct a six-week risk assessment phase, followed by the submission of a risk reduction/mitigation guideline to the Health & Safety Executive, in turn allowing a lava-walking policy directive to be issued. Only then can they put their silver suits on to go and join their T-shirted comrades who have been warming their bortsch by lowering pots into bubbling lava pools for the last few months! Of course, no offence meant to ANY of you wonderful geo profs and studes, who are obviously ALL crazy, whatever the nationality 🙂

      • ukviggen, the specialist consultant would be a psychiatrist here who would promptly section you for even having such unusual urges. 😀
        2nd post was even better than expected, the anticipation added sauce to the meal. Thanks for that.

        Typo fixed 😉 Spica

      • Thanks UKVIggen for another great post! With so many volcanoes, I’m rather glad Kamchatka and all the associated island volcanoes are on the other side of the world! 🙂
        I like the new look but have one small gripe: when there is a “hot” topic being discussed I often look in to check if there are new comments using the sidebar – this has disappeared which means I will have to scroll through every comment and, as these get into the hundreds, it will take too long. Can it be fixed? (This is a small gripe – not a major one!)

        • I bet! As a kid I used to sleep every night about a metre away from my prized specimen of autunite – probably not such a great idea and may explain a lot!
          Did you get the specimen yourself? It’s a place I wanted to go to but someone told me that the organised trips there are only run on the anniversary of the ‘event’, and only for US nationals!

    • That is a great solution for the nuclear waste problem, just forge it all into pretty gems (collectors edition) 😉

  2. UKViggen, thank you very much for this long post full of wonderful info!

    I noticed quite a few other pieces of footage of volcanic eruptions in the past by the guys from “Beeld en Geluid”. Great find! Etna, Tolbachik, Vesuvius and others can be found.

  3. Is there any possibility to get the sidebars back?
    At least the one with the latest set of comments? Without it we will miss the comments that are posted upstream… And rereading the entire comment field all the time feels like a bit much of work.

    My ten cents 🙂

    Otherwise it looks very nice!

    • I have gotten an answer in mail.
      Our hard working team of Dragons and admins are on the job allready. 🙂
      A big hand to them for the hard work they are doing!

    • This theme has a nasty thingy that was not directly evident on the test blog. It does not show the sidebar on the posts itself, but it does on the main page, which I regret as well.

      As a temp fix I’ve stuck the recent-comments widget at the bottom of each comments section, but it will maybe take some coding (if possible) to get it done properly. Or else, the coming days we will need to find another solution 🙂

  4. Yurk ! What happens to the “skins” of the blog. It looks awful on my computer. Very unpleasant to read. Please try to get the old one back. Thank you.

    • Could you please explain more in detail what is the problem.
      That way it will be easier to fix things. Problem is that the old skin was not possible to use any longer due to WP no longer fixing back bone problems.

    • We are working on it. Might be we have to fuddle around with the code a little bit. It might take some time till the appearnace is as we want it to be. Sorry for the inconvience. We want it to be readable on androids too.

    • Seem to be using Word Press 2011. Are 2012 or 2013 friendlier? The last two would be supported by Word Press for longer.

  5. Wow.fancy new interface….actually i can see teh sidebar of recent comments if i go to the main page, but once i enter the post with all the comment, the recent comments list are down at the bottom.

    BTW UKViggen, fantastic article, great photos to boot.

  6. Hi
    Here are 3 videos of the same data. I have also changed the colormap from the standard “jet” to the “hot” one.

    This is the update for the density plotting animation for El Hierro, between March 18th and April 25th.

    Mesh size is variable between 50 and 200 m.

    The size of the mesh used for calculation is shown in the title, as well as date information.
    The video is in 2 parts, the first part shows a day to day variation of earthquake density value. It shows very well the end of the swarm after April 4th with only localized quakes afterwards.
    The second part is a cumulative value during the same time span.
    One can see that there are 3 main focuses for the earthquakes, one at the western tip of the island, the second one more to the north west and the last one west of Orchilla.

    The change in mesh size shows quite well the importance of the parameter is delimitating high density area. In fact, I find it suitable to do several runs to try to find the values giving the best information.

    mesh size 50 m

    mesh size 100 m

    mesh size 200 m

    Data from Ign, NOAA, made with Gnu Octave and Avconv

  7. Great post, not so great Skins (format, font etc..),
    still miserable but hope that will pass

    Edit: freed from the dungeon, no reason why it went there….

    • It will Islander
      But as long as this last changed was compicated we will try the next theme when hardly anyone is online.
      Trust me. Any suggestions about a new header crowd??? But please with the same coloring we had. Black orange red… Just not a stretched image. The size of the images is set exactly to what the one we have is. Nothing too funky or i will feel like having taken drugs.
      Nah real reason is… easily recognisable… and not clashing with the many wonderful images our writers add to their post.

      • Thank you* I find new skins larger (more empty space on the screen), need not be so stretched out, do they? Not using the breath of the page, but I probably am bad designer of layouts. The font (the actual letters) might improve with time. But it is all hard work, I am not complaining, you probably have plenty of feedback already. *Takk fyrir

  8. Hmmm, I think I like the new format (time will tell) although I haven’t checked it on my phone yet. I can also see the most recent comments at the bottom of the page. Keep up the good work, Dragons!

    • I like the fresher look of this skin, although I will admit I find fonts with serifs (the squirly bits!) are easier to read. You will notice in older posts that there will inevitably be a few unusual line-breaks etc, as posts prepared with the old layout don’t fit exactly with the new theme – I had to fix a few strange breaks and bolds on this post – but it won’t be a big problem, and overall it does look nice!

  9. Hekla strain “trend” seems evening out, this is normal, but does not mean its diminsishing. Only dramatic falls/rises, say 50 to 100.000 units, then something is up. We need 300 K or more for eruption, like in year 2000, but there is caveat I forgot about. It is location of the crack/fissure and the relative placement of it to the strainmeters. These can show up as different readings, althou we assume it will be a “free fall in 30 minutes before eruption”. Also the HEK strainmeter (its new, not seen a eruption before) could show momemtarily an increase rather than decrease, althou this is guesswork on my part.
    Otherwise, I expect anything can happen, any day or weeks. And Hekla should remain “Rather-Yellow” on the VC warning scale, at least not hike it but once a week.
    http://hraun.vedur.is/ja/strain/1sec/index.html

    Edit: this one rescued from dungeon too

    • HEK will probably just show things for a few seconds.
      It is to close and is slowly getting squashed. Probably it will become useless in a couple of years even if there is no eruption.
      HEK was if I understand things correctly only meant for Scientific purposes to get high definition data before the actual “strain-spike” starts. Same goes for the FED station.
      Kind of scientific cannon fodder. They will give warning, but die during the initial attack.

      • Yes, some stations will eventually be fodder, but HEK will not be so crushed as you propose, It think it might suvive, it needs a lot of punishment deform a simple (12 inch?) drillhole in solid rock. It probably is also covered over by gravel and only lava (heat) can render it useless by cutting off power to it. But many of the GPS and the FED SIL might be crushed/squased/torn or roasted then .. and btw BUR is back online.
        – Now only the SIL´s hopully make a comback.
        * no sorry needed for rescuing this from Dungeon, name edit is all it takes for it to land there 🙂 I already am in my Dungeon (Bed) inbetween periods of minimal activity, such as trying feeding myself but it does not work all the time … so only Liquid tonight (and strictly “Non- ” version I am afriad). Sorry for helth history, makes me feel better to tell the universe. 🙂
        * and Carl, I like you much better as Befuddled person 😉

  10. @UKViggen:
    Splendid read, loved it!!!
    Ferro-olivine basalts was not what I was expecting!

    • Thanks – and also to everyone else for their nice comments.

      Hmm..basalt. Quite. It’s quite an old volcano and (I’m guessing) arose as a more andesitic strato. There is also the fact that it lies slightly behind the main arc to consider. Some scientists have suggested (more like idle speculative chat really) that there MAY be some connection with Lebedya and Grigorieva – perhaps a ‘line of weakness’ that runs away from the plate boundary?
      Plosky Tolbachik is also pumping basalt in a typically andesitic region, and right next door to an andesitic stratovolcano (Ostry Tolbachik), but admittedly Plosky is a more typical basaltic shield-type shape.

      • One thing I should add is that the scientists admit that the age of Alaid has been estimated on very circumstantial evidence. They noted that the older volcanic formations have all been well-covered by much younger activity.

            • I can’t begin to think what you mean there Carl. 😉 Are you another crossword fanatic? Sounds like you would be good at compiling them.

            • No, it is my mother who is the crossword fanatic. Golden rule in my family is to never disturb my mother or my brother untill they have had their morning crossword and soduko.
              They are worse then heroinists before the morning fix…
              I just sit in the couch muttering silently with a huge mug of coffee in the morning.

  11. His honour and reputation were fully restored in 1954

    …Yeah, I bet that did him a lot of good. He’s dead Jim!

    It’s one thing to say you’re sorry, but if a government has gotten to the point to where the arbitrary killing of the citizenry is lightly dismissed as “Opps, were sorry” then it needs to be torn down and the idiot bureaucrat responsible drawn and quartered. “Opps, sorry, you seem to have pissed off your citizens. All better now?”

    Pitchforks™ They’re not just for tossing hay!

    • Oops, sorry for killing you has always had one big problem to it… Dead is rather final.

  12. Commander Chris Hadfield on the International Space Station has just (well, 18 hours ago) tweeted this pic of a volcano in Chad, but with no name. Does anyone here know please?

    Here’s a handy guide of where in the world the ISS images are of: https://cogsnscc.maps.arcgis.com/apps/OnePane/basicviewer/index.html?appid=0d1b3909ad9944dab7e29354f465ade7

    Edit: was stuck in dungeon

    • Could you imagine a rifting event from TFZ to Bardadabunga? Horrible thought.

      Also not very damn likely. It would be a huge Black Swan if it did.

      (bold added for the idiots at the loon sites)

      • Thankfully that is not evident in the GPS data. It seems that it will only rip open from Krafla up to north of Grimsey.
        The GPS really went berzerk after the onset of that quakeswarm.

        • it won’t open for such a length in the north neither. That would be the Black Swan of all Black Swans. 😉

          • Actually, it has opened before for a very long stretch of it. What we are seeing is the Theistareykjarbunga swarm. And that one has opened in it’s entire length on occation. But, we are at least a hundred years away from that one popping.

            • When did this event happen?

              How did scientists show that it opened in its entire length? More than half of these 100 km are under the sea surface.

            • Oops… me being fumbly here.
              It has opened down to roughly Krafla, and up to the coast. The rest is unknown how/when/if it has opened.
              But the swarm stretches quite long out north. It was though not known untill 2008 that it was a microplate driving the process. I wrote an article about it sometime long ago.

  13. I’ve re read the article and I re iterate my compliments to UKViggen. Great post.
    You make a reference to a unit I’m not familiar with “mcm/s”, could you explain to what it refers please ?

    • In short, I don’t know. I recall we had the discussion here before, and no-one came up with a conclusive answer then. When I wrote it I thought to myself ‘Someone is going to ask what this is!’ and here you are! It seems it’s a distance measure per second figure, but not sure what it relates to. To confuse matters further the Russians (or at least EMSD) use a measure that is expressed as (figure) x 10^-6 mps (the figure times 10 to the power minus 6, presumably metres per second). That would be microns per second. Hope someone here can clarify!

      • Je vous en prie DFM, j’ai trouvé le sujet Alaid très intéressants 🙂
        C’est la valeur du tremblement ou de l’amplitude volcanique qui est calculé en mètre seconde. En Russe мкм/с (mcm/s) n’est rien d’autre que le mètre par seconde.

        • And losely translated (excuse my french, it is très rouillé)…

          “Please DFM, I found the subject of Alaid very interesting 🙂
          This is the value of earthquake or volcanic amplitude calculated in meters per second. In Russian мкм/с (mcm/s) is nothing other than meter per second.”

          And here I go and bang my head against the wall… How obvious! Thank you Shérine!

        • I be darned, I understood this as metre per second, a speed unit
          *I mean I understood the French, not the Math 😉

  14. Post updated with Alans Evil riddle:
    My true dusky identity was hidden! My secret lies in my blackness! Confused?
    What am I?
    Who are my relatives?
    Where can I be found?

    • Alan said this is the last riddle he will send. He is leaving us.
      He most likely wont even do the Dinging. (He also mailed the answers.)
      Please help me to ask him to stay. Please.

      • Yes Spica, it is most definitely please stay Fred from me!!! Wont be the same without you Alan, I can cope without the evil riddle (easily 😀 ) but will miss you if you leave. Don’t do it is all I can say. Even infrequent visits would be good.

      • Nooooooo! What would I do without my brain workout at the weekend?

        Alan, you must stay – even if it’s just to pop in now and then! 😦

    • My guess:

      Dusky = snowflake obsidian
      Secret blackness = normal, black obsidian
      Relatives = sheen obsidian and rainbow obsidian
      Found = locations which have experienced rhyolitic eruptions.

      Iron and magnesium typically give the obsidian a dark brown to black color. WIki: http://en.wikipedia.org/wiki/Obsidian “Very few samples are nearly colorless. In some stones, the inclusion of small, white, radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern (snowflake obsidian). It may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being cooled. These bubbles can produce interesting effects such as a golden sheen (sheen obsidian) or an iridescent, rainbow-like sheen (rainbow obsidian).”

  15. The Sheepy Dalek bar will be busy today.
    Here is another riddle for you: By our very own Kilgharrah!
    NtV Riddle

    1 point for each volcano and 1 point for each red herring ….

    No 1 – Lethal lahars; Siblings; Satellites; Volcanic group;
    No 2 – Mild vulcanian; Cult leader ‘residence’; Lava bombs; 1874;
    No 3 – Silent movie; Northern Europe; Legend of ill fated lovers; Two calderas;
    No 4 – Flank fissure eruptions; c4 mile glacier; 1921; Emperor penguins

    You people are being spoiled, i hope you know that.
    HAVE FUN!!!!

  16. I understand you’re all in riddle mode, but you might wanna have a look at etna’s tremor graph 🙂

  17. Hi

    This is the update for El Hierro since April 12th.

    There were some modifications as this video is now in 6 parts

    Part one is the event by event evolution since March 18th showing the quakes localization and magnitude (for Mag over 3).

    Second part is a day by day evolution, third part is the same viewed from above.

    Fourth part is rotation of the complete swarm

    Fifth part is a rotation with a view from above from the whole swarm and finally the sixth part is a progressive zoom on the last earthquake.

    For the earthquakes from March 18th to April 12th (empty circles) I have kept only those with MAG over 3 for better visualization.

    In Cyan (small dots), are all the earthquakes prior to March 18th 2013

    For the new ones, all Mags are shown.

    Circle diameter is proportional to earthquake magnitude.

    Current earthquake size (in red) is proportional to earthquake magnitude x 8.

    The scale for magnitude is shown on one side of the plot (up to 4).

    The new earthquakes (between April 12th and April 25th) appear as filled circles.

    There are some late earthquake in older zones otherwise no big changes since the last update. Mainly small quakes, the main swarm is over since around April 4th.

    The title indicates the position of the earthquake in the count since March 18th (“Count”)

    Date of event and hour are shown also with magnitude.

    Colorbar shows event position on the left and terrain elevation on the right

    Earthquake data come from IGN, Terrain from NOAA, made on Gnu Octave.

  18. First riddle thoughts: Nigerite (Ferronigerite) or Swartzite. Must rush – have to get dinner ready before Ash Cloud Apocalypse! 🙂 (Channel 5 – UK viewers)

  19. Not to complain, but I really, really, really, (did I really say really?) really liked much more the old layout of this blog. Much more easy-to-follow I think.

    • We still have a blackhawk SIL down or two. 🙂 I know they are up and allot of you guys can see. Just wanted to place in a movie thing for friday. 🙂

      • OK. Yes, there are lots of Helos still down.. (Blackhawks are such), but BUR is fixed, they probably do not know the last kick did fix it 🙂
        * I go rest in my Dungeon

  20. Well, “Iceland: Ash Cloud Apocalypse” was fun. They had their facts right but presented them as though we were about to be engulfed in a volcanic winter if Katla blows. Hekla was called a diva (I don’t think she’ll like that) and Laki will kill thousands. A bit over the top! But the pictures were lovely! 😀

    • I was also impressed with how many of the facts were accurate, but not with how over the top they were on the doom-mongering. And I spent a substantial amount of time shouting at the telly when they were banging on about how Laki is unique – I think that Veidivotn and Eldgja might have a bone to pick with that..

      • Yes, they also made it sound at one stage as though they’d only just found out about Laki! But, take out the sensationalism, it was quite good on presenting how geologists work out what’s happened in the past and what may happen in the future.

    • LOL Talla, I am glad you thought it was a bit over the top too! I did learn a lot though.but not as much as I already knew thanks to all the good folk on this blog.

      • Yes! A couple of years ago I knew nothing about any of what they were talking about – now I can tell if they are talking nonsense or not. All thanks to here! 🙂

    • OOOH! That does look odd! Let’s hope all settles down. I don’t want to see another Mount St Helens in my lifetime. Wonderful if no-one had been killed. Sadly too many people were, including the volcanologist Johnston i think his name was who said it was unsafe and was only there because he had to change a shift with someone else. So very sad, the only one truly alert was killed.
      http://sthelenshero.homestead.com/DavidJohnston.html

  21. Alan’s 😈 riddle:

    Skutterudite: “is a cobalt arsenide mineral that has variable amounts of nickel and iron substituting for cobalt with a general formula: (Co,Ni,Fe)As3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, annabergite, nickeline, cobaltite, silver sulfosalts, native bismuth, calcite, siderite, barite and quartz. It is mined as an ore of cobalt and nickel with a by-product of arsenic.”

    Source: http://en.wikipedia.org/wiki/Skutterudite

      • I really hope it is not goodbye forever – just an “hasta la vista” from Alan – Fred aka almost every name under the sun since the start of this blog – you will be so missed by so many if you leave.& .how will we know what the wood pigeons are up to if you are not here to give us the latest report ??? I have really enjoyed “meeting you” here…….even though I have never met you in person, you seem to me to be a really great guy….will never forget the orange overall photo! Wish you all the best whatever you decide …very best regards, Debbie x

  22. I’m not allowed to play tonight as Daughter has come home to visit, she did however give me this picture to share with you all. Doin it Ganglamb style – http://i43.tinypic.com/wlyert.jpg perfect for the volcano cafe dance off 🙂 if the riddles remain unsolved after the has gone to bed, then i may get a chance to play. good luck all. x

      • bloody internet – keeps translating this entire blog & all comments into Spanish for me – you would all be so impressed with your linguistic skills if you were sitting where I am! Over past weeks my internet has behaving reallt weird – think I need to get reformatted or something….

      • jeez Kelda thought you were talking about me there. shit caught out again….just realised it was your daughter ..I have been in Tenerife since 1988 and have not seen UK TV since then until now—have managed to get it so am pretty much watching anything the BBC or ITV want to throw at me! 🙂

  23. Just in case Karen doesn’t have the correct answer to Alans riddle, (I think she does though) I will go for Jet or lignite as the answer. Jet is not considered a true mineral, but rather a mineraloid as it has an organic origin, being derived from decaying wood under extreme pressure. In this case it’s relatives would be coal or anthracite. The best place to find it that I know of is Whitby, North Yorkshire.

  24. Thank you ukviggen for this excellent post. Very much enjoyed the reading!

    “Olimpiyskiy flank eruption” 🙂
    Shall we call Etna´s next paroxysm “Championsleagueoxism”?

  25. I am not sure about the new format here. Maybe another glass of Vin de Plonk will get me used to it!.
    An answer for Volcano #4 Beerenberg. First climbed in 1921. Huge glaciers miles long to the sea and the most Northerly Volcano that has flank eruptions….Since it’s in the Arctic there are NO Penguins…maybe red eyed herrings in the sea but definitely no penguins.(Emperor Penguins are red herrings).

    Alan leaving? Surely not ! I have just about got my brain nicely convoluted. My brain needs Alan.
    I waited all week for that programme about Iceland’s Ash cloud. Husband went to bed early and I just started watching it, a snuggled up nicely with Meg on the sofa….door bell went… and yes a visitor. I couldn’t watch it due to making cups of tea and offering sympathy!!! wasn’t a happy bunny !

    Oh! I do miss the IMO tremor graphs…..I hope they come back soon.

    • Diana
      You should see my testblog thingie. The background is dark and all links bright orange. it looks like an explosion.
      We are testing stuff, as i said above this is NOT final. Something may look ok if you test it, then suddenly it is very different with tons of comments. Suddenly you notice arg upps sidebar gone.
      Expect a few more changes within the coming days. Till we finally find a version with which we and most of the crowd are happy. ( You can never please All)

      • For bein a beta-test it is though working pretty well. I just get confused by the comment thingy bein at the bottom. But… I am starting to lean to that it is the best place for it to be…

      • No worries Spica….I am just tired tonight and a bit grumpy 😀 I must admit the bright orange explosive thingy sounds alarming…It wouldn’t be good early in the morning before coffee #1 ….:D

  26. I want to stay up and watch Etna.
    Problem is I spent most of the day cutting down and removing a shrub that thought it should have been born a tree and had decided to reach 12 feet before staring to die. After sawing off the branches then excavating the root system and sawing through those also before getting two hefty fellers to remove the trunk for me, I now find I ache in places I didn’t know it was possible to ache. Dilemma is. Do I put up with the ache and watch Etna, or do I take painkillers and sleep! What would you do!

  27. Volcano # 1 Nevado del Ruiz. Covered by glacial snows it has produced many deadly lahars the 4th most lethal lahar ever recorded. 1985 saw the town of Armero wiped out and 25.000 people died. it belongs to a group of five ice-capped volcanoes which includes the Tolima, Santa Isabel, Quindio and Machin volcanoes.[6][7] there are 5 lava domes (siblings), all constructed within the caldera of an ancestral Ruiz volcano: Nevado El Cisne, Alto de la Laguna, La Olleta, Alto la Pirana, and Alto de Santano.[13] I therefore the red herring is satellites

  28. There have been 3 earthquakes, the last is the one we see on the earthquake map. The two first one where approximately 0,6 and 0,8M. All 3 at the same location roughly.

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