Sunday, 18 April 2010

Ash clouds: Eyjafjallajökull

Just a few words on ash. Here in Britain all aviation is shut down, as it has been since very early on thursday morning. Why? because of a cloud of volcanic ash,  hurled into the sky by the icelandic volcano known as Eyjafjallajökull.(Ash is actually a rather incorrect name for it. Ash, I think of as the residue left after combustion. This is not residue after combustion, ejecta might be more correct, mineral matter, spicules of basaltic glass. One airport "spokesman" was rambling on about ash and soot. He seemed to think the air was full of soot too. What a muppet. He will be earning vastly more than me of course, so I'll try not to feel too critical of his lack of understanding about the events which have closed down his industry. Maybe he's really good at powerpoint presentations.)
Journalists around the world are tripping over their tongues trying to say Eyjafjallajökull. There are a myriad different versions out there. Once upon a time, the BBC had a pronunciation department whose job was to make sure newsreaders didn't make fools of themselves. Would it be so very difficult for the TV stations to call the Icelandic embassy, or Icelandair, or anywhere they can find an icelandic person, to ask for the correct pronunciation?

Eyja means "islands", (Ay-ya) fjalla (fya-tla( means mountain, jökull (yer-kutt) means glacier, or icecap,  "Ay-ya fya-tla-yerkutt", there's a slight "l" sound on the end, not a full-fledged "l",  not quite "tl", just half an "l" sounded. That's as near as I can get. From memory.
I'd imagine it got its name when early norsemen saw it as one of the first sights of land to the west of Norway, they thought it islands, then, closer, saw it was a mountain on a bigger island, covered in ice.
The volcano is in the mountain, beneath the glacier, and so the active crater first caused a huge icemelt which flooded rivers and washed out roads.

 Another Icelandic Volcano, Hekla, 
as described by Abraham Ortelius in 1585
The latin text "Hekla perpetuis/damnata estib. et ni:/uib. horrendo boatu/lapides evomit" means "The Hekla, perpetually condemned to storms and snow, vomits stones under terrible noise."

The blast of the eruption coincided with  a period of calm weather, low winds, so up there, from 10,000 to sixty thousand feet in a broad swathe across the north atlantic, scandinavia, and western europe the air is filled with highly abrasive dust. It melts onto, and clogs jet engines. It stops them. Which is not a thing you want to be present for.
It will abrade the surface off glass windscreens, leaving a plane flying blind, it will block instruments. So aviation has shut down, totally.
It's strange. Looking up, we see clear blue sky, not a trace of any visible cloud. Yet its up there. My car is covered in a fine film of dust. No more than if I'd driven a half mile of dusty farm road.
Yet there are no lines in the sky, no vapour trails. No faint, far-off rumble of jet engines throttling back as they line up on the airport.
No police helicopter clattering about in the night sky. No yellow air-ambulance rushing busily toward the helipad a couple of miles to the west.
No little planes, no weekend pilots, no military heavy-lifts.. It's only when they're not there that you notice how much a part of the daily scene are machines flying in the sky.

Just close by to this eruption is the sleeping giant, Katla.
If Katla erupts, this one will look like a pimple in comparison. There's also a lot more ice depth over it, so the mudflows and flooding will be far more aggressive.
I've flown over volcanoes a couple of times, as I think I posted about before, close enough for the skin of the plane to become too hot to touch inside the cockpit. And close enough for the noise of things hitting the plane to be louder than the engines. Both were propellor-driven, not jets, but I'd hate to think of how rapidly that stuff was clogging the intakes.
The wings, in which the fuel tanks live, were even hotter.
I loved living in Iceland, even though it was often cold, wet, and windy, it's a beautiful country,  sitting over the junctures of two tectonic plates, it's the place where the Mid-Atlantic ridge is exposed above the surface of the ocean, where you can see geology in action, land forms that can change in a matter of days- minutes, even.
Where you can see new-born rock, hold it in your hand, the magma of our planet's interior.

And right now, some of that's sifting down out of the sky, all over northern europe.

Following comments, a couple of links that will help explain why flights are grounded.
Speedbird 9, or the Galunggung Glider.
BBC-How Ash Affects Airliners.
Boeing, Volcanic Ash Procedures.
BBC current situation reports.

A KLM  Boeing 747 flew into ash over Alaska in 1987, all four engines stopped. They were successfully restarted at 14000ft, and the aircraft landed safely, but the less than six month old plane suffered $80 million in damage, including all the engines having to be replaced.


  1. Thanks for that. Now I understand why all those flights were grounded. I assumed it was just a visibility problem. Yikes!

  2. Our Earth has said"Oi!!" and we are forced to give it some relief from the fumes and noise of flying.

    I bet the positive effects of no flying will be sidelined, just as they were last time flying was reduced drastically.

  3. Good grief!
    Two comments whilst I'm still writing the post.

    Nag. It's mostly invisible, if you were flying into the danger zone your eyes wouldn't warn you, nor would your radar. The first indication one 747 crew had, flying into ash on a flight between Malaysia and Australia, was light sparkling discharges on the screen St Elmo's fire from static electricity in the dust, then, one-by one, the engines shut down.
    They were coated internally with basaltic glass, remelted in the heat of the jets.
    The cooling vents were blocked, titanium compressor blades coated and eroded.
    Luckily, some eighty nautical miles later, and having lost altitude from 37000 to 12000 feet, they managed to restart an engine, then the other three, although one failed again.
    I'll edit and put a link up to some explanatory tech stuff.

    gz: Nope. You can't pull in the Gaia hypothesis. How does that take into account Pompeii? Or that Icelandic eruptions have been happening regularly since the island was first discovered?
    It's just something the planet does, without any connection to the activities of the nasty infestation of humans on its skin.

  4. gz: further reading. Naughty old Gaia and a filthy bit of global pollution. An eruption that hurt the people so badly that a whole nation forgot all its dances, forever.

  5. This activity is what we don't usually see.
    Is there anywhere else that the earth's "expansion joints" are above sea level?

  6. There are quite a lot of plate boundaries above the ocean surface, but most, like that along the west coast of the americas, are convergent, where the earth's crust slides together, quakes yes, volcanoes not so many. Iceland is where divergent plates spread apart, the crust ripping open.
    Which is pretty handy, for geothermal energy. In Reykjavik you get two water mains into your house, hot, and cold. Water from far beneath your feet is piped up to run through your radiators, and away again into the drains.
    You go out, put the dishes in the sink, leave the hot tap trickling. No need for detergent. By the time you come home, it's all sparkly clean.
    Out in the countryside, hot pools, under the stars, after a day climbing in snow, lie back and let the hot springs soothe your aches.

  7. I am trying to compare this eruption to Mt. Saint Helens which erupted with a huge bang, back in 1980. I lived about 1,000 miles from there & I remember "ash" on my car the morning I went into labor with my first child on May 21st of 1980. this is a magnification of the ash. I do remember that although it was fine, it was also gritty when wet.(like superfine sandpaper)

    The pictures that I've seen of Iceland, makes it seem alien to anything I'm used to.

  8. i've been trying to ignore the story on the radio so that i might stumble into something with more accuracy and voila... here it is. even though our species is such a burden on the ol' mother, she is still literally awesome. love the video too. btw... i rather enjoy the grounding of planes

  9. This has just been posted on a thread on forum

  10. Rita: I remember Mt St Helens, seeing it on tv, it was an event many magnitudes greater than the present one.
    I seem to recall quite a lot of people were killed, i recall the sunsets afterwards...
    The physical characteristics of the eruptions were very different, Eyja... is not really an explosive event, unlike St Helens, which blew about a quarter of the mountain into the sky as its opening gambit.
    That was a scary one. Like the growing magma dome beneath Yellowstone park. Stay away, kids.
    I'm impressed you can remember the ash on that particular morning, I'd have thought your mind would be too full of the impending birth to think of ash.

    Jim: This is a public service blog. We exist to edutain and occasionally mislead the public. Our Chief Editor is not to be relied on, but occasionally he's lucid for a while...
    We potters are earth, air, fire, and water junkies. In my case, I'm hypnotised by fire. Volcanoes and waterfalls and the northern lights all fascinate me.
    The no-flying thing does too. I love flying too, despite its non green credentials, I love to see the world spread out in miniature, perfectly detailed. Ten years ago, flying from Thailand to the U.K, I saw the Himalayas from above, those folds of the earth, mythical mountains, if i fly, I want the window seat, I'll watch clouds, vapour vortices off the wingtips, anything. Flying over the Himalayas! I looked around, and most other people seemed to be asleep or watching the movie. My God, people, look! It's the roof of the world! Everest, Kanchenjunga, how can you not want to see?

    gz:Ha! that downsizer! It made me laugh, For a start, CO2 is the least of your worries. So it emits less CO2 than aircraft? That's good then. Let's not mention the toxic sulphur dioxide, the acid rain, the hydrogen fluoride, hydrofluoric acid....
    Volcanoes are dirty things, they have no emission control whatsoever.
    All the resources you might need in the event of volcanic activity are here...(The International Volcanic Health Hazard Network)-

    Seriously speaking, though, I think Downsizer's article takes a very dangerously simplistic view, and quotes figures that are in fact impossible to quantify, no matter who you find to quote, the truth is we have no way whatsoever of measuring the volumes/masses of gases emitted, we can sample specific areas, hold a wetted finger to the breeze and guess, that's all.
    We can be accurate only on tiny areas, and none of those can be close to the centres of activity. Downsizer's article is about as trustworthy as necromancy.

  11. It wasn't an article by downsizer, it was something somebody found to add to a thread on downsizer forum.
    Perhaps you ought to add your fourpennorth!! Join in and discuss, informed discussion is welcome.

  12. Ahhh, I see! Sorry, I misread/misunderstood the link, thought it was downsizer, which i admit I'd never heard of before.
    Though I do love a good argument, I'll refrain from entering that particular debate. I think the writer just didn't think it through.


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