Airspace begins to open as Eyjafjallajökull calms down

Eyjafjallajokull erupting on 4/17/2010, image by Marco Fulle. Note the "rooster tails" of ash and steam, typical for Surtseyan eruptions.

European airspace has slowly begun to reopen as the explosive eruptions at Eyjafjallajökull have become less intense over the last 24 hours. However, there is still lots of hazardous airspace and airports around places like London and across the UK remain closed - leaving people stranded. We will still have to wait to see what the political ramification are, especially after EU officials claim "flaws" in their decision and the over $1 billion losses by the airlines. There is still a persistent 3,000-4,000 meter ash plume coming from the crater, which isn't too surprising considering the strombolian-style activity, which can also have periods of reinvigorated activity. You can see some of this style of eruption in the webcam capture from last night (below) - you can make out the incandescent blocks and ash being thrown from the crater. It is hard to get a scale out of the image, but the blocks could be meter-scale chunks of lava coming up in the vent. You can get another perspective on these spasmodic explosions by watching the video taken from a helicopter yesterday, showing a "pressure wave" that represents one of these explosions occurring in the crater. Each explosion is a large "bubble" of volatile gases in the magma escaping at the vent, causing fragmentation of the magma and the explosion we see. This might also explain some of the loud explosions that have been reported today near the volcano.

Eyjafjallajokull exhibiting strombolian-style eruption on the night of 4/20/2010.

All eyes, including satellites, have been trained on Eyjafjallajökull over the last week. Two pictures posted yesterday at the NASA Earth Observatory show the changing ash plume from the volcano over the weekend. The BBC has posted a nice collection of satellite images as well that capture the range of remote sensing we have up in orbit. There is an amazing collection of land-based pictures as well on the Big Picture - and check out another fellow Scibling if you're curious about the volcanic lightning. You have to be impressed with the response of the Icelandic officials and people to this eruption, even with some dry Scandinavian wit: "It seems we're getting pretty good at exporting our disasters." If you want to read my take on the threat of ash to airlines, you can check it out on Dot Earth over on the New York Times website - and nothing like people seeing faces wherever they can find them.

More updates as they arrive ...

UPDATE 1: If you want more video of the "shockwaves" at the crater, this video was recorded by Omar Ragnarsson at 5 o'clock GMT this morning. Stunning stuff. {Hat tip to Palmi Egilsson.}

UPDATE 2: The ash plume might have cost the US economy ~$650 million according to U.S. Travel Association.

More like this

National Geographic film crew near Eyjafjallajökull, April 18, 2010. UPDATE 1PM EDT 4/19/2010: I can almost categorically say that Hekla is NOT erupting, contrary to Twitter or the brief banner on MSNBC. See my comment below (#68). In what is sounding like a bit of a broken record, the eruption at…
A shot of the summit area of Eyjafjallajökull, showing the twin steam-and-ash plumes from the lava flow and active vent. Picture taken by Dr. Joseph Licciardi (UNH). Over the weekend, the newly reinvigorated ash eruptions from Eyjafjallajökull combined with favorable winds meant that ash from the…
A shot of the strombolian activity at the vent of Eyjafjallajökull, taken on May 4, 2010. Image courtesy of the Iceland Met Office. The latest news from the Eyjafjallajökull eruption has the volcano erupting more explosively again (see above), possibly due to an increased influx of water into the…
Webcam capture of Eyjafjallajökull erupting on May 2, 2010. You can see the steam plume on the middle flanks of the volcano - this is likely a lava flow coming from the summit vents. A brief update on activity at Eyjafjallajökull: Overnight, the lava flows from Eyjafjallajökull could be seen in…

A big thanks to you, Erik, and all the comments from readers! This is a much needed site not buried under the media frenzy.

I have read about Katla, and came across this website - http://www. godlikeproductions .com/forum1/message1042490/pg1

Just wondering if there might be the slightest possibility in it since I'm heading to Europe.

Once again, thanks all.!

@Joyce - I wouldn't trust GLP to offer much in the way of reliable information. There have been little/no signs of impending activity at Katla.

Erik, Chris - Thank you! That was wonderful reassurance. GLP got my panic button switched on for a while :)

GLP? You mean the "I am an alien ask me a question" site?

Okay... that was good for today's snicker.

GLP is good for wild arsed theories from a different perspective, but you absolutely HAVE to take what you find there with a grain of salt... and a shot of whiskey.

Are we getting any news/feedback of the flights over Europe? Do the current flights prove what the companies have been telling (no risk in the test flights)? Hope the media or companies would not hide this crucial information in order to continue the business.

By fire walk with me (not verified) on 20 Apr 2010 #permalink

Glad to find this blog. Really great to get info from a professional and not filtered through the media.

Repost from the other tread.

Currently there is more steam and ash coming from Eyjafjallajökull. I guess that means maybe a new ash period is starting soon.

This volcano has given me lots of interesting images and videos to look at, but the shockwaves becoming visible in the plume is the most fascination thing I saw so far, this was totally unexpected for me! Has this phenomenon been described before?

BTW today I didn't try to get the images for a time-lapse movie. I am living in a energy-efficient house and the computer running 24h a day made my home-office room uncomfortably warm!

@Jón, careful careful - the increased plume thickness can very well be due to the bad and humid weather, rather than increased volcanic activity. That's a thing we see often at Etna and which can be terribly misleading. Volcanic tremor shows no increase - the plots at show a clear decrease instead, and the data recorded by your seismic station are stable.

I found a way for us to still view the Vodafone cam (Be nice to it!)

Type the following into your browser BUT KEEP READING BELOW:…

As you can see in the URL, they are saving minute by minute images to a date based directory structure. As long as you change the date and time to the current hour in Iceland, you can view the most current image by refreshing.....for now. You can also go back and get any picture from the past using this same method.

For example, as I type this it is "2010/04/20/14" (YEAR/MO/DD/HR). Next hour, you will need to change it to "2010/04/20/15/current.jpg"

@Boris Behncke, the air is quite dry there at the moment. Like often happens in Iceland around this time of year.

Visibility is currently poor at the moment.

i'm a doubter...
i want more info than 'magical' before i go somewhere.

@Jón ... Boris seems very critical of you .... perhaps he is jealous over your track record on this one? :)

Jón I swear you that what we see here is very humid weather, at least up there on the mountain (it may be dry where you are but that's not at the summit of the volcano).

Look at these two photos of Etna, taken both when the volcano was NOT erupting, and there was no change in the gas emission (like sulfur dioxide) between the two images, just a change of weather conditions:

You can't imagine how often people think there's a serious eruption when they see something like in the first photograph.

@motsfo's not spam, honest. If I say 'source to sink' would that convince you?

Just to make this clear, I don't want to criticize anybody just for the fun of it. And Jón has delivered so much precious information here that it may seem bad to contradict some of his statements. But if you look at the webcams in this moment, the veil that hides much of the scene, that's ... what? Cloud. What's cloud? Water vapor. That's what causes the condensation of water vapor in the eruption plume and makes it appear much denser, and that's what we see also in the Etna images. In the first Etna image you see blue sky but that means nothing. Air humidity varies extremely even at a scale of a few tens of meters vertically and that is also well visible in the first of my Etna images - you can see that thin cloud layer just below the summit. There you can be sure humidity is close to 100 per cent, and 50 m higher it's maybe only 20 per cent.

I hope our friend Jón takes this just as an educated chat among people with a high level of education, and as an occasion to exchange experience - I do have, humbly, a lot more experience with volcanic plumes, since I live near Etna since 15 years and that volcano constantly emits gas and often also ash plumes.

Re. the "shock waves", here's my quasi scientific analysis: Not really shock waves at all, but pressure waves. For shock waves to form the gas exit velocity would need go supersonic. Kind of like the difference between the sound a balloon makes when it pops and the sound an M16 makes when the bullet leaves the rifle barrel. The reason you can see the pressure wave is that it increases the density and the temperature of the air as it approaches, causing the refractive index to change. The difference in refractive index causes light to change direction a bit as the wave passes, producing the contrasts radiating out from E-J's throat seen on the video.

By dougl mcl (not verified) on 20 Apr 2010 #permalink

@Jón, Boris. From the Mila webcams it is obvious there has been snow falling on Eyjafjall in the past two-three hours. If you take a close look at the Ãórólfsfelli web cam (15.18 GMT), you will see that much of the steam is rising from the ash-covered area around the crater.

Vertical tremor output has inflected again and appears to be on the increase.

Or you may go to the Vodafone Picasa site and look through the pictures from appx 11.00 and on to see the snow actually fall.

Poll Tax in the "£$%^ing sky! Tories opening scottish airports before english ones as we are %$£"^&ing expendable. EXPENDABLE!!

Anybody comment on the pressure waves...? Are we talking about pressure waves or sound waves, what is the difference...? on the video they seem to originate in an explosion, since a magma explosion visibly follows. Can anybody measure the speed of these waves on the video, to compare with speed of sound in air...?

@Boris Behncke, I have a system that I use to figure out what is the ash cloud and what is the normal weather cloud. I am also looking at the web cam real close. So it was easy to spot trough the mist, even if I was bit unsure how much this change would be. As that is just wait and see kind of a thing.

Harmonic tremors are once again slowly moving upwards. But this phase that Eyjafjallajökull is now in can last of months, of not years. So I am not expecting anything big soon. But I am not surprised if a big thing happens without much warning at all.

@Henrik, There might have been snowfall there. But it is easy to see that from the ash fall. But I don't remember how the windfall was this morning.

@dougl mcl #20 your explanation sounds plausible...

At this point, let me tell you a true story. An officer colleague of mine who was teaching at the Army NBC centre once had to hold classes for reservist NBC specialists. One of the reservists had gone on after his National Service days to become a professor (European, not American sense of the word) in neurochemistry and had specialised on neurotoxins including Chemical warfare.

In this situation, my friend let the professor do the teaching after which he would add the odd comment and clarifier. The Professor would nod and say that he should have included those. So, instead of revealing to everyone his own scant knowledge, he appeared to be as learned as the professor. ;)

North and South transform fault systems remain sporadically active and appear to march lockstep with vertical tremor activity at Eyjaf, an indicator of a larger expansive force trend with the MAR. Repeat pattern: both transform faults and central fissures firing in sequence.

Grimsey fault on the Tjornes TF system has very interesting forces acting upon it in 3-space, according to recent reports, and explains in part the repetition of minor earthquakes at this location.

Erik, SO is back up.......

Great pictures...

By M. Randolph Kruger (not verified) on 20 Apr 2010 #permalink

@dougl mcl [#20]

"Re. the "shock waves", here's my quasi scientific analysis: Not really shock waves at all, but pressure waves. For shock waves to form the gas exit velocity would need go supersonic."

Not sure if it helps, but one of the oddities that stood out about base surges was how they could get faster than the speed of sound. The answer was that the air in front of the surge front was superheated as the wave approached, ramping up the pressure and speed of sound at the same time.

Dunno if volcanic ones act the same way.

I want to put the claimed economic losses by the airlines in perspective. The $200 million per day figure is about the cost of a new Boeing 777. You don't have to lose too many to make it not worth flying. You're more likely just to trash the engines (and the cockpit windows and paint on all leading edges), but that still adds up to $millions.

By The Gregarious… (not verified) on 20 Apr 2010 #permalink

@26: Sound waves are just pressure waves (travelling waves of compression or shear stress, depending on the medium) you can hear.

By Emanuel Landeholm (not verified) on 20 Apr 2010 #permalink

If the amount of ash being fed into the stratosphere continues at this rate can and will this cloud begin to affect North America

Fluor = 850mg/kg of ash? Jay-sus!

By Reynir Heiðbe… (not verified) on 20 Apr 2010 #permalink

I have been reading and thinking about the claimed possibility of this eruption increasing the probability of a Katla eruption. I found this diagram most helpful;;nid=1485383

I'm not a professional but think I've been able to follow the gist of the ideas. As I understand it the two volcanos have separate magma sources, which might interact but only much lower down. However, the situation (the magma) is fluid ;-) and the pressure now in the Eyja system causing the present eruption could cause its magma chamber to spread underground. (See the part of the diagram labelled 'Laggangar'). If this spreads so that it breaks into the Katla magma chamber it could have catastrophic consequences.

Two extreme possibilities, depending on the different pressures in each magma source: If the Eyja magma source is at much lower pressure then the Katla magma chamber could drain though it, worsening the Eyja eruption but losing pressure under Katla caldera causing it to collapse at the part labelled 'kvikuholf'.
OTOH, if the Eyjaf pressure is much greater than that at Katla, it may just make that volcano erupt as it may be an easier route to the surface than it presently has.
Many inbetween possibilities are not so interesting but much more likely.

Am I completely misunderstanding?

Hmf! The top of the glacier is fogging up right bad, but since the wind is expected to shift clockwise to W and then N, there's a hope it'll clear up tonight.

By Reynir Heiðbe… (not verified) on 20 Apr 2010 #permalink

Jon's helicorder seems busier

@ Ben / 11

thanks for pointing that out! I have been using the archive for some time-lapses last week, but I have assumed that it also became available when the vodafone webcam was limited to an icelandic audience.

Of course with a picture only every minute the temporal resolution is not very good, but better than none!

My script is already downloading "yesterday"

@evan bj Thanks for the link.

As I rummaged around the site I found this bit, which somehow I missed. ABC landed a crew on the volcano by the current eruption. I found it in the rightmost column with the tag

Amerikansk TV-team landet på kanten av vulkanen

Jón I do agree very much that the situation is likely to continue to evolve for some time (unless all eruptive and geophysical unrest comes to a full stop). And there is now indeed a slight increase in volcanic tremor amplitude - notably the lower frequencies, which means the seismic "noise" is lower, more like the deep rumbling of a lava fountain, whereas a rise in the mid frequencies is usually due to vigorous Strombolian activity. So it is possible that soon we will see some increased activity, if weather conditions and load on the web cam sites permit.

The sound or pressure waves that are well visible in some videos are a phenomenon that has been first described about 100 years ago as "flashing arcs" by volcanologist Frank Perret. This phenomenon is well documented at Sakurajima in Japan and here's a whole bunch of videos of explosions at this volcano, which are very often immediately preceded by such shock waves: (>200 short video clips of explosions) - a particularly good one is here:

Diane, OT, but have you noticed that odd, persistant chain of quakes around Eureka?

I'm sure this link has been in some previous post but I missed it. The parent directory of the seismo chart that we have been looking at is very nicely organized with a bunch of useful information, such as the locations of the stations. I didn't realize but the stations are on Katla, with GOD being the closest to EJ. HVO is on the opposite side of Katla from EJ which is why it has a weaker signal. What I didn't realize is that all of these corders are pretty close. The directory has raw data from the individual stations which helps to give some perspective.

One of the most fascinating charts is the one that shows the cumlulative earth movement -- 1.4E+15 Newton meters whic is equivalent to,,,, well as far as I know nothing that man has produced...

@ doug mcl (20), @ Kris B (26) and @ Lurking (32):
There was an eruption on Vesuvius in 1906 when a very good photo was taken: (there is a good description too:
It shows two sound waves (propagating outwards from the blasts in the crater) that changed the refraction rate of the airmass involved. It simply pressed the airmass, the more dense airmass had a different refraction rate than the neighbouring airmasses that's why it is observable. The same happens when you see a fata morgana (mirage) but for different causes.
The shockwave we can see on the video goes back to the same causes, the mass of the eruption cloud is pressed by a wave generated by blasts below. We simply see the more dense waves rushing across the cloud.
With some supersonic aircrafts something similar happens when they cross the sound barrier, the more dense airmass makes the vapour content to be nucleated and there is a cloud being born around the plane. If you google "sound barrier" you'd find many good examples.
So the physics behind all these phenomena is the same.

@ Boris (44) Well, I see you have outran me with quite good examples too, the last link of Sakurajima is perfect for showing the cause of the wavefront travelling across the cloud before the blast occures. :-)

@ Mike (49) - This sounds like this joke:

What was the last wish of Icelandic economy?
To have its ashes scattered over Europe.


If this is how the Gods indicate that they are displeased by dodgy banking practices then I had better move out of the Cascade range (in the U.S.A.) pronto!

Hey all, dunno if anyone is looking at the mukalot cam at the mo, it's absolutely beautiful! The sun looks like a nuclear explosion on top of Eyjee :)

@monica #47. Thank you for the shockwave explanation. I've a favorite video of top 10 low pass jet flybys. I've been puzzled by the #1 flyby at 2:53 in the below link. It's got the ring you described, but there's no sonic boom-- is it that the plane is too far in front, and the video ended before the boom, or is there some other explanation for the ring?

Also, at 2:28 one can see what it's like to experience a high pressure wave of air.!

Quite a lot of steaming activity seen in the Valahnúk web cam now.

For the lovers of the "flashing arcs" or shock or pressure waves, this is a web page with a number of extremely high-quality videos made by my friend Thorsten Boeckel at Sakurajima and Suwanosejima volcanoes in Japan earlier this year. This was posted on the Eruptions blog at the time but probably has drifted into oblivion due to the eruption at Eyjafjallajökull, so here I refresh that information:

And here's another really really powerful video made by Thorsten's travel companion Martin Rietze:

I don't know about Norse Gods revenge, but this morning during an interview, a National Public Radio (US) correspondent made a snarky comment on Icelander's feeling a bit smug wrt 'volcanic payback on Europe' for taking heat over the bailout. That was uncouth of NPR and atypical of their standard of news journalism.

Oops, 2:13 for the experience of the pressure wave! Sorry :-p

Last night I watched the Late Show with David Letterman and he made a few jokes about the volcano, and said the pronunciation was a little bit like saying "Eh, ya forgot yur yogurt"

@ Monika [47], @ Boris [44]
thanks for the reference to Frank Alvord Perret regarding the explosion shockwaves, however the circles in Perret's photo strike me as not part of the original photo, since they are not concentric, and their centers are high up in the air, not down in the crater, like in the videos...

@Passerby 55: I didn't hear the NPR program, but I can't help thinking that it is poetic justice. (especially the part about how the UK used anti-terrorism laws to seize Icelandic assets.)

By Tennyson Lee (not verified) on 20 Apr 2010 #permalink

There's another (Icesave-related) joke out there: "UK and the Netherlands demand cash from Iceland, but since there is no C in the Icelandic alphabet, all they get is ash."

By Reynir Heiðbe… (not verified) on 20 Apr 2010 #permalink

@ Boris & Monika

Thanks for the background info!

I am aware of the images of fast aircraft with clouds around them. Such shockwave/pressure induced condensation actually happens already below the sound barrier. It is frequently visible on airshows when the humidity is high when the planes are well below Mach 1.

The change in refraction due to the shockwaves can be seen very clearly in this picture:

And I just remembered that there was a rocket launch this year where a sundog (parhelia) was "destroyed" by the shockwaves emanating from the rocket:

What follows below is part of the wikipedia entry on shock waves. I think it is conceivable that explosive decompression of gases in the throat of a volcano could exceed sonic velocities, but I think you would see a very pronounced jet and debris would tossed up many thousands of meters above the summit. Maybe this happened at some of the "heard round the world" historical VEI 6+ events?
Shock waves form when the speed of a gas changes by more than the speed of sound.[2] At the region where this occurs sound waves traveling against the flow reach a point where they cannot travel any further upstream and the pressure progressively builds in that region, and a high pressure shock wave rapidly forms.

Shock waves are not conventional sound waves; a shock wave takes the form of a very sharp change in the gas properties on the order of a few mean free paths (roughly micro-meters at atmospheric conditions) in thickness. Shock waves in air are heard as a loud "crack" or "snap" noise. Over longer distances a shock wave can change from a nonlinear wave into a linear wave, degenerating into a conventional sound wave as it heats the air and loses energy. The sound wave is heard as the familiar "thud" or "thump" of a sonic boom, commonly created by the supersonic flight of aircraft

Phillip @ 41 - The current.jpg file actually seems to update every 10 seconds or so but an images is saved to the folder every minute.

@ Boris & Monika

Thanks for the background info!

I am aware of the images of fast aircraft with clouds around them. Such shockwave/pressure induced condensation actually happens already below the sound barrier. It is frequently visible on airshows when the humidity is high when the planes are well below Mach 1.

The change in refraction due to the shockwaves can be seen very clearly in this picture:

And I just remembered that there was a rocket launch this year where a sundog (parhelia) was "destroyed" by the shockwaves emanating from the rocket:

I often read the different science blogs in an effort to increase my knowledge, but I am by "no" means a scientist. In fact, I am a social worker, so please be patient with the following question as it may sound absolutely ridiculous to many here:

I read about a year ago on a science site that earthquake activity could cause increased volcanic activity up to 500 km away. Now, I understand that Haiti's earthquake as part of the Caribbean plate is a a lot further away from Iceland, but could the "vibrations" of this Haiti quake, somehow effect the Atlantic Ridge tectonic plate which runs right through Iceland? Again, apologies if this is a stupid sounding question....but my Mom always taught me that there are "no stupid questions"....Thanks. "An inquiring Lurker"

By AlwaysOptimistic (not verified) on 20 Apr 2010 #permalink

@Kris B (#58) and Monika (#47): in his original publication on the "flashing arcs", Perret admitted that in the photo he had manually drawn the arcs, because he had been unable to capture the phenomenon in photography. He also noted that maybe he had centered the circles too high above the crater.

The original article is "Flashing arcs; a volcanic phenomenon", which was published in the American Journal of Science, Series 4 Vol. 34, October 1912, pp. 329-333; the on-line link with pdf for purchase at US$ 8 is here:

#64, there does appear to be a regional connection between volcanic and earthquake events, but the modeling is complicated and promotion mechanisms are not so well understood.

@AlwaysOptimistic (#64) - although an effect of large earthquakes (usually those much larger than magnitude 8 - whereas Haiti was a magnitude 7.0) on volcanoes and also on nearby earthquake-generating faults is now considered possible, you must consider that Eyjafjallajökull has been preparing for this eruption since more than 15 years. That is, the first seismic unrest was recorded in 1994. So it appears certain that the volcano would have erupted in any case, maybe the shaking of the very powerful (magnitude 8.8) Chile earthquake on 27 February has accelerated things a tiny little bit.

Parclair #45, yes I have noticed them and I think they are after shocks of the 6+ they had up there. The seaward edge of the Cascadia subduction zone is just off the coast from Petrolia. There is a break in the fault line on the shore and then it turns into the Whale Gulch Fault. I would wager they are the same and it just may not have been found. It is like the San Andreas. Just south of the Mendocino Fault, there is a small part of the San Andreas that is on the coast. Then there is a break and where it comes up again it is called the Mendocino fracture zone. I think the Mendocino fault and the San Andreas are one and the same. It heads out across the ocean for about 3000 miles! When I took geology, the teachers figured the San Andreas went out into the ocean for that many miles. I am not sure what the geologists are saying now, but that was the thinking back then.

I really don't think at this point it is anything unusual. I have seen plots like that before. What I am watching is S CA where the quakes from the Baja quake moved north along the fault. It seems right now it is quaking more near the border than in Baja. I will be watching that.

I may be getting tiresome, but I remind others that the history of this volcano has been that periods of uncanny quiet precede strong changes of course.

In recent hours I reviewed Michel Socuel's new animation of the evolution of the magma transits under Eyjafjallajokull from 4 March until the most recent eruption -

It shows that (among other things) the "exploit" of the pipe used for the major early April eruption (the earlier expanding and cracking open phase) occurred more than 3 weeks before, on 14 March or so. After that the magma showed very little activity... just its applied energy elsewhere including forcing that new fissure on the north side... then all was quiet for a couple of days.

Then boom, it was coming out of the caldera. No seeming warning *except* that awesome quiet and a few other factors which I read as possibly suggesting a "leaning" in the westerly direction. It was another "Loki" move (who was not the one bound, by the way... that was Fenris, Loki's wolf... Loki lost an arm in the final battle, using the dwarf-made magic chain to seal Fenris' mouth shut for the final conclusive time... a "magic battle" against Hekla most likely... and to finally seal him away underground).

So I suggest that we just hold our breaths a bit and not jump to any conclusions about this being "over." The fire is strong, is possibly being fed by Katla's magma plumbing a bit, and is historically able to keep resurrecting itself for a many-month period.

To Dr. Klemetti and other regulars here - thanks for the great information and professional insight. Fascinating indeed!

With all the recent earthquake speculation around, does anyone have a recommendation for a good science-based blog/website, similar to this one, that discusses seismic-related events?

Wow, check the dirty snow/ash in the valahnjuk webcam

@70 stigger, I was wondering why i was seeing an airliner at high altitude over central scotland, flying south.

Just look at Valahnuk camera: you can clearly see intense ashfall.

By Renato I Silveira (not verified) on 20 Apr 2010 #permalink

Passerby and Boris....Thanks for responding to my question in such a civil manner. Asking questions on this site, with so many informed people commenting here can be intimidating.....:)

By AlwaysOptimistic (not verified) on 20 Apr 2010 #permalink

@Boris(66), thanks, yes, it is apparent that Perret's arcs are too narrow, compared to the real thing, so illustration, not documentation, thats exactly what I thought the arcs on Perret's photo was, after I'd tried myself to 'catch' the arcs from videos, they're rather elusive, would need high frame rate to work well.

The speed and number of arcs for each explosion indicates a fast initial burst of not a very high number impulses, and pilots near the eruption report hearing it as 'bang' on the fuselage of the aircraft.

But people farther away report hearing thundering blasts, like reported at Vik i Myrdal 40km away. So the initial burst of impulses is dispersed with distance, like with lightning thunder.

There is snow on the Mukalot cam as well. Temp is about 1 celcius (you can see the current conditions in the link to follow but that is on the ground below the volcano.)

Doesn't look like a good day for viewing. Depressingly similar to the lousy view out my window here in Washington. Maybe I'll get the house cleaned before my wife comes home so she won't know I spent the entire time viewing pictures on the internet. (No, not THAT kind of picture!)

Hmm, verdur; weather. I must confess that Icelandic is beginning to look partially comprehensible now. Not quite ready to compete in the Icelandic spelling bee, though. ;)

Snowflakes mixed with ash particles, it appearas to me. Thorosfelli cam also shows them. And the cloud looks pretty much like a plume.

By Renato I Silveira (not verified) on 20 Apr 2010 #permalink

@70: BA is taking advantage of a forecast window of opportunity (clear skies) between 7pm-1am that will allow long-haul landings at specific airports in Ireland and Scotland. Their intent is to bring home the backlog of UK passengers stranded overseas, many who have been waiting since last Thursday to return. It's a prudent alternative to presently congested clear-air skies over Spain.

Remarkably, foreign airlines have voluntarily cooperated with European flight planners, by canceling or postponing transatlantic scheduled flights to allow regional hoppers and long-haulers to move weary European passengers and perishable cargo around first.

@ Boris (66) Thank you very much for the info, well it seemed to be too perfect for early 20th century photographing technics, but as I have also saw the effect on videos, I thought it was a really lucky shot for Perret. By the way it is the phenomena what counts now. :-)

@ parclair (53) I think Philipp gave the answer regarding the humidity. That plane was over a water surface so there must have been lots of vapour in the air.

@ Philipp (63) That pic with the plane and refraction is awsome!!! It's a very good illustration of the phenomena. Thank you for sharing! The APOD image, well I have seen the SDO launch online and saw the sundog disappearing. Only hoped that someone had shot a video containing the images of the shockwave. There was a 14 yrs old girl, Anna Herbst who had.
How could it happen? For a sundog you need some ice crystals that has very similar orientation, and if a shockwave rushes across them they will lose their orientation. Refraction still happens, but not on the proper facets of the ice crystals so the coloured pattern disappears.

For starters, you might want to visit the USGS IRIS website. It has dedicated pages for software downloads. One useful bit of software works as a browser plug in with Google Maps, allowing you to download and analyze EQ data for regions and quake centers. It's free.

There are other EQ software packages that you may be interested in, depending on your level of knowledge, expertise and need:

Civil Aviation Authority in the UK says all airports can re-open from 10pm tonight (9pm GMT).

By suzyk2002 (not verified) on 20 Apr 2010 #permalink

@72 Michael Cerulli Billingsley

Mythology check. Both Fenris and Loki were bound. Here's a translation from the Prose Edda regarding Loki and earthquakes:

"Now Loki was taken truceless, and was brought with them into a certain cave. Thereupon they took three flat stones, and set them on edge and drilled a hole in each stone. Then were taken Loki's sons, Vili and Nari or Narfi; the Ãsir changed Váli into the form of a wolf, and he tore asunder Narfi his brother. And the Ãsir took his entrails and bound Loki with them over the three stones: one stands under his shoulders, the second under his loins, the third under his boughs; and those bonds were turned to iron. Then Skadi took a venomous serpent and fastened it up over him, so that the venom should drip from the serpent into his face. But Sigyn, his wife, stands near him and holds a basin under the venom-drops; and when the basin is full, she goes and pours out the venom, but in the meantime the venom drips into his face. Then he writhes against it with such force that all the earth trembles: ye call that 'earthquakes.' There he lies in bonds till the Weird of the Gods."

@Michael Cerulli Billingsley #72

Your description is not only INCORRECT, it is also MISLEADING. You CONVENIENTLY FORGET the M3+ (3.4?) that seemed to close off the Fimvörduhals eruption. You also deliberately(?) leave out the intense earthquake swarm that preceeded the eruption and led Icelandic volcanologists to issue a warning and recommend an evacuation because an eruption was imminent and might possibly have started.

I am not impressed nor amused. Please get your facts straight - they are availble!

Tremor sensor output up sharply; jump in EQ activity to the North again.

Showtime. Heads up to NATS and UK Met Office.

The Ãórólfsfelli webcam - - shows a dense, white to light gray plume, that means lots of water vapor, not too much ash for the moment. The tremor levels are back to the same levels as yesterday - even higher than that in the moment I write this; throughout the day there have been reports about very loud detonations. So I guess what we have here is pretty powerful Strombolian activity. With a bit of visibility (Ãórólfsfelli is currently the one that shows more than cloud and dark snow or ash flakes), at night there should be a good light show again.

It aint over till the fat lady sings! I think we have a long way to go with this eruption. There will be times with lots of ash then periods of lava and even at times nothing

By Chance Metz (not verified) on 20 Apr 2010 #permalink

The increase in tremors means exactly what Harald described in his blog (as linked in yesterdays thread here on Eruptions) is occurring again. Magma is moving to the surface, degassing and 'rattling' the pipes as it encounters cooler temperatures.

Hah... Jón is already on the case! Great mind think alike... and fools seldom differ :-)

@ Jon Friman. Thanks for the auto-refresh progam for Mulakot. My sore and cramping fingers thank you too ;-D

Hi there. I´m looking at the vodafone cam, thanks for the "current" link. I´m also looking at the Valahnuk cam. It´s a lot of white steam/smoke at the moment, has it been like this for long?

By snotra viking (not verified) on 20 Apr 2010 #permalink

Parclair, can you direct me to the instructions of the mulakot cam, can´t find them?

By snotra viking (not verified) on 20 Apr 2010 #permalink

I have a question on ash cloud tracking. The higher elevation remnants of the first strong eruption seem to be leaving the eastern boundary of the VAAC-London tracking graphics, but isn't showing up on Alaska or Japan VAAC charts. Is there a graphic available from remote sensing that shows where it is headed and at what concentration? I'm curious if and when it will show up over the NE pacific and if we will be able to observe any difference in our Seattle sunsets this week.

Jon's site that auto-refreshes the mulakot cam (thanks Jon!) is at

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Passerby wrote:
'Grimsey fault on the Tjornes TF system has very interesting forces acting upon it in 3-space, according to recent reports, and explains in part the repetition of minor earthquakes at this location.'

Any chance you could expand on that in layman's terms? I've noticed that it's been rumbling away up there for a few days.

Thanks in advance.

By Mike Richards (not verified) on 20 Apr 2010 #permalink

Thanks @ Frito Lay, for the link.
( and Jon of course, for providing ist!)

@ Lavendel YW. IIRC it auto-refreshes every 1 minute.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

I see planes over my home... Newcastle (UK) airport is open for buisness... Have looked at their arrivals board and they are expecting approx 28 arrivals tonight..

Suw #108 sounds like a good title for a novel. LOL

Parclair, did you see my answer to your question about the quakes near Eureka? It's #71. What part of CA do you live in? I live in N CA

I think they've had a little snowstorm at Mulakot!

Re the pressure wave. Another possibility (I lack enough data to say much but this is what I remember) is that if there saturated steam with both liquid and gas phases, the speed of sound can be quite low, on the order of 100 km/hr not the normal 1,000 km/hr. This makes it possible to generate shock waves more easily.

This shows up in rupture valves for liquid tanks in fires, where the liquid is boiling as it leaves the pressurized tank and in CO2 fire extinquishers. (from my school days in the 80's)

There has just been a small eq at EJ

@Phillip that BBC series "Invisible Worlds" had a good section on shockwaves. Really in an explosion, it's the shockwave that does the damage and can kill you, not the explosion itself. Usually it's invisible, but here in ultraslow motion you can see it but we saw it in the volcano!! :P

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

I would strongly caution between making any suggestions on what a particular eruption would do based on cultural records alone, although they may provide some hints on where to look in the geological record for past events.
But this is the key, the physical evidence present in the geology is where we really learn about a volcano's eruptive history (also keep in mind the eruptive history provides important clues to what a particular volcano can do, not a guarantee on what it will do). This involves getting down on the ground, mapping, collecting and analyzing the deposits of past eruptions, as well as looking at older exposed rocks from deep in the crust that tell us what is going at depth in these volcanoes. This is particularly important where we have no historic observations of eruptions from a dormant volcano.

Rant alert! What the general public may not appreciate is how underfunded such basic geologic field studies are today. Many newly minted geology PhDs who specialize in research fields such as petrology, mineralogy, geochemistry and volcanology cannot not find the positions to do the research I just described. The problem isn't that there are not enough research problems to go around, it is the sad fact that many university geology departments have decided that there is no longer a need to teach such basic geology courses as mineralogy, petrology, geochemistry, structural geology and field mapping. As such specialists retire they are not being replaced.

In short, to truly understand the hazards and history from any volcano we need people trained and employed to do the research, but the positions and funding to do the work is not considered important or even necessary by many university geology departments and government agencies. Sorry, rant over.

Diane, i saw your note, thank you. I've just been kind of alerted (feeling) to all the movement northward north of SF ending at the Cascadia Subduction Zone. In addition, there are all the big stressors to the zone coming from Canada and Alaska in the north. Idle watch, is all. ;-)

I live in the flatlands of No Cal. I think you're pretty lucky to live at altitude!

You're right, great novel title in 108;-D

'Olafur Grimsson: Eruption is only 'small rehearsal''

Iceland's president is blunt on near-future risk of additional eruptions.

I think this might not be such a bad idea to make the warning loud and clear, even if the Geological Institute isn't too thrilled: Europe, you got your learning-curve event. Pay heed or pay the price.

@116 If only the pols and the people who elect them in the US were as thoughtful *sigh*

@EKoh I agree. Why geology has become so underfunded is a mystery to me. It's such a vital field.

From the newly linked article about loss in the US due to volcano:

While safety must always be the primary consideration, economies, particularly those recovering from recession, cannot afford an overreaction that stifles travel completely," Roger Dow, the association's president and CEO, said.


"Safety is the primary consideration unless it costs me money at an inconvenient time."

I'm really appalled at the politicization of the issue. I bet the same sort of people who are crying now about an "overraction" were crying that we didn't do enough to get people out of New Orleans with 36 hours notice of a hurricane that could have decided to turn in a different direction at any time. I even find the argumnent percolating through the media that since we can fly today (if we can...) it means that we could always fly -- despite the vast differences in the ash produced by the volcano from day to day.

If I don't get wet when I go outside today, it means that You were overreacting when you told me to carry my umbrella last week.

Maybe we should just do away with emergency services predictions entirely. "Oh, all the planes in Europe crashed? Too bad." "Oh you got hit by a Tsunami? Oopsie!" "Too windy? Guess you shouldn't live in a Hurricane zone!"

Yes, a pressure wave can cause water vapor to briefly change state from vapor to droplets (fog/steam) and back again. You can see the same with high performance aircraft flying at subsonic speeds in humid conditions.

So as the pressure wave migrates through the vapor plume, the compression may cause a state change from vapor to fog and back to vapor again causing the wave to be quite visible.

Mulakot cam is clearing up again, no sight of the ash plume yet though.

By snotra viking (not verified) on 20 Apr 2010 #permalink

Ref my post 104 regarding recent small earthquake (1.4) in the EF region, I am slightly surprised that (bearing in mind the interest in tremors) that this has not been taken up. Isn't it important?

There's a load of interesting cross talk on shockwaves going on that I'm enjoying reading, but I wondered if anyone has any info on the rising vert tremors god, esk and mid over the past day? I don't think they've changed the scale at the stations like they did a while back, so i figure they are definitely ramping.

There appears to be far more water coming off the glacier on the latest vodaphone picture.

123: Yes it is important, but it was also expected.

@123 mattlee, I saw that too. I think Jon is looking at the quick succession of tremors under Kverk. Any thoughts Jon?

@ Kaboom #125 I was just noticing the same thing. There seems to be a heck of a lot more water down below than there has been for days.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@parclair: Rant alert from Gordy; I feel why the Earth Sciences have become underfunded in America is because it does not buy votes. Politically I am as close to the middle as can be. America has become polarized, no place for someone in the middle. I don't have anyone to vote for anymore, it is more about who I am voting against. Funding is about the votes and the party. Earth Sciences don't buy votes...unless it's related to Global Warming. I am sorry about the rant people, I know this is not the forum for politics. Rant over.

@Erikh 114: good rant.

@Danny, If there is more water coming down, it means that a new melt has started under the glacier in Eyjafjallajökull.

The earthquake that did just happen might have been a indicator of that. But it depends. Now it is just wait and see on what is going to happen.

* Doing a upgrade to my Gentoo Linux, it is breaking things on it.

Meltwater would be expected with rising magma and uptick in light-colored (steam) plume emissions.

For the person who asked after the Grimsey/Tjornes Transform fault zone:

Start with:….

I can't send you the paper, but the abstract with do:
Fault interaction and stresses along broad oceanic transform zone: Tjörnes Fracture Zone, north Iceland.
TECTONICS, VOL. 29, TC1002 (2010).

Transform motion along oceanic transforms generally occurs along narrow faults zones. Another class of oceanic transforms exists where the plate boundary is quite large (â¼100 km) and includes several subparallel faults. Using a 2-D numerical modeling, we simulate the slip distribution and the crustal stress field geometry within such broad oceanic transforms (BOTs). We examine the possible configurations and evolution of such BOTs, where the plate boundary includes one, two, or three faults. Our experiments show that at any time during the development of the plate boundary, the plate motion is not distributed along each of the plate boundary faults but mainly occurs along a single master fault. The finite width of a BOT results from slip transfer through time with locking of early faults, not from a permanent distribution of deformation over a wide area. Because of fault interaction, the stress field geometry within the BOTs is more complex than that along classical oceanic transforms and includes stress deflections close to but also away from the major faults. Application of this modeling to the 100 km wide Tjörnes Fracture Zone (TFZ) in North Iceland, a major BOT of the Mid-Atlantic Ridge that includes three main faults, suggests that the Dalvik Fault and the Husavik-Flatey Fault developed first, the Grismsey Fault being the latest active structure. Since initiation of the TFZ, the Husavik-Flatey Fault accommodated most of the plate motion and probably persists until now as the main plate structure.


Pore-fluid pressure greatly affects the probability of failure and reactivation of the faults, both in the South Iceland Seismic Zone and in the Tjörnes Fracture Zone. A detailed study has been made of the mineral veins (old channels of geothermal water) on the fault planes in the Pleistocene rocks of the South Iceland Seismic Zone and in the Pleistocene-Tertiary rocks in the Tjörnes Fracture Zone. It is likely that changes in fluid pressure can be transmitted over considerable distances and thus trigger earthquakes in areas relatively far away from the source of the initial pressure change. Fluid pressure also affects friction on fault planes, hence the probability of fault slip.

Grimsey fault sits in a very active geothermal field area.

The new flood started just before 21h local time. Check photo 26.jpg (last one before it gets too foggy) and 59.jpg (first one after the fog lifts) here:…
26 has low level of water, 59 has much more water.

And the earthquake happened sometime around 20:15:

So looks like the flood is related to the earthquake?

Hm. Seems the UK Met Office is adhering to a set of restrictions but the Civil Aviation Authority has removed all restrictions.

Today's "ash map":

From the Guardian:

"All UK airports are reopening tonight, after the Civil Aviation Authority announced it was removing restrictions on airspace."


"Dame Deirdre Hutton, chairwoman of the CAA, said flight restrictions could be lifted because none of the no-fly zones caused by the volcanic ash cloud are currently over Britain."


""Since the flight restrictions were imposed, the CAA have been working around the clock with the aircraft manufacturing industry, the airlines and the research community to better understand how different concentrations of ash affect aircraft engines," Lord Adonis said."


""The major barrier to resuming flight has been understanding tolerance levels of aircraft to ash," the CAA said. "Manufacturers have now agreed increased tolerance levels in low ash density areas.""


""This has been a difficult period for everybody," Walsh said. "I don't believe it was necessary to impose a blanket ban on all UK airspace last Thursday. My personal belief is that we could have safely continued operating for a period of time.""

"A Downing Street spokesman said: "The prime minister welcomes the decision by the Civil Aviation Authority to allow UK airspace to be used from this evening following rigorous analysis and testing of the flying conditions.""

The whole article:…

The funding issue is only part of the problem, and while more money would be good, I'm afraid it would go where it is going now, a metastising admin, athletics, amenities to attract well-heeled undergrads (who can pay high tuition) and high-attention research that gets lots of grant overhead and attracts alumni donations, which goes into admin, athletics etc.
Unfortunately, there is also a political or cultural issue within the science of geology. There is an attitude of many people running departments at universities with regards to "hard-rock" and field geology that "nobody does that anymore". I'm afraid there is a small, but vocal and influential part of the surface processes field in geology that has disdain for the "hard rock" field. I must add that most surface process geologist do not have this attitude and understand the importance of fundamental education in all aspects of geology. That's just my opinion, and I've wasted enough time veering off-topic.

But for the general public out there who are really interested in the science and think that its important, I would just ask that you make sure that the university geology depts. your tax dollars support, at the college you attend or send your children to covers the science in all it aspects. And if it doesn't ask why.

Back to the volcanoes!

>"I don't believe it was necessary to impose a blanket ban on all UK airspace last Thursday. My personal belief is that we could have safely continued operating for a period of time.""

Well, that would be discrediting reports of aircraft damage to RAF and NATO fighter jets, and numerous science flights to monitor and obtain dust samples under supposedly clear skies. The former flew just a few hours before the first commercial plane test flights the other day.

The plume concentration conditions today are said to be substantially improved, suggesting that it was NOT safe to fly, say, this past weekend.

@EKoh: Thank you. Back to volcanoes.

@ Tennyson Lee (141) I can't understand why politicians are let to talk about scientific things... :-(

>"I don't believe it was necessary to impose a blanket ban on all UK airspace last Thursday. My personal belief is that we could have safely continued operating for a period of time.""

It really depends on how much risk one is willing to accept. With damaging concentration of ash apparently visible (as was the case with the finnish F16's), it would be a lot more risk than I would be willing to accept. Also, keeping the commercial flights running would pressure people who are on business to take them regardless of their own personal feelings about their safety.

By Tennyson Lee (not verified) on 20 Apr 2010 #permalink

@Tennyson... he is right of course.. No one knows when Katla will wake up but it is just a matter of time and if she runs true to form then it could very well be sooner rather than later.. I can understand why he likened Eyjafjallajökull to a dress rehearsal.. When Katla blows..... well who can say but I for one am looking forward to her performace...

Are their Live Cams for Katla? I'd like to bookmark them. Thanks!

@ Monika 145: Presumably, the leaders have to (or at least should have to) understand these things to make good decisions.

On a related note, I remember a press conference held by NASA immediately after the Columbia incident. It was held by engineers and scientists (apparently unmuzzled) instead of the more typical spokesperson or politician. Despite the circumstances, I remember it was so refreshing to actually hear the truth complete with technical details instead of generalities and spin.

PS. I meant "invisible" (not visible) in @146

By Tennyson Lee (not verified) on 20 Apr 2010 #permalink

Different subject - YELLOWSTONE NATIONAL PARK, WYOMING just had a Magnitude 3.5 earthquake (2010 April 20 21:49:30 UTC. It has been rather quiet for weeks.

By Greg Lennes (not verified) on 20 Apr 2010 #permalink

Read Harald's article re: harmonic tremors, but wonder if someone can point me to more extensive articles/books about this subject.
Starting from scratch reading seismology textbooks is the best way I guess, but there are numerous seismology books...

Do tremors at "god" seem to be escalating?

Wise words from the Icelandic President.

Nature is in charge here. The Europeans and the rest of the world must get their heads out of the sand and prepare for known historical natural disasters that will repeat themselves.

By Les Francis (not verified) on 20 Apr 2010 #permalink

USGS eliminated the earthquake for Yellowstone - sorry

By Greg Lennes (not verified) on 20 Apr 2010 #permalink

@ Tennyson Lee in 146 - The Finnish Air Force doesn't have any F-16s, just F-18 Hornets. (Link is in English)

The visibility's gotten quite a bit crappier on most, if not all, cams - hope the weather in southern Iceland clears up by tomorrow morning at least.

Thanks for the heads-up, Gordys. The heat-signature imaging was made in response to an explicit request to NASA at the start of the eruption.

Look at Fimmvörduháls! This data was collected yesterday. I *wondered* if the western fissure area was still showing an active thermal profile.

Way to go NASA! Thanks Rob Simmon! You're the best!

How unusual is the nearly 72 hours of continuous harmonic tremor? (both in regards to duration and amplitude)

What is the significance of the different frequency components (0.5-1 Hz, 1-2 Hz, 2-4 Hz, etc.)? My very limited understanding is that sub 1 Hz is the most indicative of magma movement.

By Tennyson Lee (not verified) on 20 Apr 2010 #permalink

A big thank you to Einar for posting the wonderful link to the old maps of Iceland yesterday. I sent the link to my dad and he loved them. I'm really enjoying reading here and learning. Thank you Dr. Klemetti!

"The harmonic tremor however continues to increase and they don't know why that is."

Wouldn't it be obvious that the harmonic tremor continues because magma is moving under the surface? There could be any number of explanations. Is the surface inflating? If so, then perhaps a reservoir of magma is "recharging" from below. Not inflating or deflating? Maybe it has found an old lava tube and magma is flowing that isn't obvious from the surface ... yet.

I may have no idea what will happen next but the name of our Volcano makes more sense now. CNN had a humourous piece on the problems people are having with pronouncing it, but in the middle an Icelander explained the meaning (as to a child) and I get it. Icelandic is apparently economical with spaces.

Eyja = "Island"
Fjalla = "Mountain"
Jokull = "Glacier"

So say those three things as they look and you will get (maybe?) close.

(Apologies for losing the umlats, they just confuse me anyway.)

So E.J. is a pretty good abbrievation but E.F.J. would lead people down the right path.

@George, the surface is in fact deflating at the moment. So this is a mystery. For the last few moments the harmonic tremor has been dropping quite fast. This actually quite interesting, as I have never seen his before in Icelandic volcano. At least not this type of pattern.

>The harmonic tremor however continues to increase and they don't know why that is.

Hahahah. Eyjaf *may* be taking an intermission break while preparing for Act III.

Anyone else notice those tremors dropping now? It's odd.

Hi Jón, can you help with this: When did they say they "don't know why?" or to that effect and how long ago did they say it?
And do "they" have any speculation or concerns as to what it might be? Thanks.

By Dylan Ray (not verified) on 20 Apr 2010 #permalink

@Dylan Ray, they don't speculate in the media. But if there is confirmed flood it might mean that the increased harmonic tremor is because of water under the glacier. It was observed early in this eruption that floods and water building up created higher harmonic tremor. I am not sure why that might be. But it is a possibility.

Just a suggestion but could the decrease in tremors be because whatever was moving (water or magma)has met a blockage of some sort and pressure will now be building up behind it?

By Margaret Attlee (not verified) on 20 Apr 2010 #permalink

While the tremor has dropped from the high levels of the past several hours, it appears to have simply gone back to the same level as it has been for the past several days. Overall on a longer trend starting at, say, 1800 18APR, the trend in tremor is basically flat. Tremor is back to what it was at about that time.

As for inflation, which station do you use as being representative of the current eruption site? I would think it would be station THEY.

To determine what is actually happening there would take a level of data, access, and dedication that I fear few of us here have. If I had a genie that could grant me wishes of data, I should like to have a radar map of the surface. And then another in two days time. That might tell me what I want to know. I am looking for places where the ice has dropped. That might point out where there might be a lava flow at the ice/surface boundary. There are all kinds of other things I wish I had, along with the time to study it all.

BBC has posted the aforementioned ABC video of the helicopter crew landing on the edge of the crater. Weird film segment attached at the end is a testimony of ash accumulation at ground-level, downwind of the plume.

@167: I'll take 'found another route' for 200 points.

The collapse in the tremors start just after the 1.4M earthquake tremor @20:21:49


Totally OT but nice to see a fellow gentoo user. Dare I ask if you have "helicorder" among your USE flags? :-)

OnT: I think I'm hopping volcano interest to Vanuatu. Goodbye and thanks for all the fish, Eyjafjallajökull. It was nice knowing you!

179 Raving - That would suggest a release of something rather than a blockage as I speculated in 177. I'll keep my mouth shut.

By Margaret Attlee (not verified) on 20 Apr 2010 #permalink

Monica, thank you for responding to my question about the jet halo. lol I love that pilot;-)

#175 Scarlet Pumpernickel

Googlespeak: "There is a simple line between gosórói and kvikusteymi, it is a challenge that needs to see better," said Magnus Tumi.

He said something to the effect that the interaction (correlation?) between the eruption activity and tremors is puzzling and the matter needs further study.

A quick remark regarding an earlier rant on funding for science. I think the issue isn't so much that "funding science doesn't get votes" but more like "attacking science does get votes". In the US in particular, doing science and being a scientist is being painted into the same corner as "big government/anti faith/ urban liberal elitism". As a scientist and engineer, this seems really bizarre since the US is the source of much of the modern worlds most elegant and beneficial science. But it turns out that scientists are easy targets when the attacker deliberately and hypocritically deploys insinuation, misrepresentation, hyperbole and outright lies while the defender tries to rely on facts and rational explanations. Most of us are in the middle, but most of us are not scientists and many find the simple arguments of those attacking science easier to understand than the usual overly complex and subtle defense of the scientific method.

It looks like Eyja is taking the night off. Peace and quiet for the inhabitants of the area, I suppose, but sad for me. I was quiet enjoying the nightly fireworks display.

By beedragon (not verified) on 20 Apr 2010 #permalink

Well, there is science and there is "science". When people find mistakes that would fail a high school science fair project that causes the data on which literally billions of dollars of funding to be completely bogus, it falls into the category of "science". And once that is found to happen in not one but in several cases, people begin to lose any trust in those who are conducting the science. This is particularly true when those conducting the science benefit in a monetary sense from their own conclusions.

Can I just ask if anyone is considering a Bardarbunga or Kverkfjöll eruption? The SIVFZ is more than likely connected to them through some of the south west fissure swarms from either, and there's been more earthquake activity there than around E.F.J over the past few days.
The closest seismo at skr has shown an increase too. A lot of people are worrying about Kata, but it's quiet as a mouse at the moment.
Does anyone have any good gps data from either of these two to just put minds at ease.
Or am i missing something? :) Im not an expert, im a Statistician. :)

If the main reason for the extreme ash production at EFJ was the water from the glacier atop the crater pouring on top of the lava, would it be feasible to avoid something similar at Katla by removing as much ice as possible from the vicinity of the crater? Yes, I understand the logistics would be bloody awful, and the work dangerous.

By Birger Johansson (not verified) on 20 Apr 2010 #permalink

Sounds like there is science that you agree with and science that you don't. It is usually scientists who find mistakes in each other's work (they love to do it; don't think it is all one big happy family) and as far as I know there isn't any example of simple mistakes that have affected literally billions in science funding.

In my view, there is "science" and then there is "science reporting." The difference is that the latter is not peer-reviewed and I have never really seen a reporter suffer any embarassment from being wrong. To be fair it is really difficult to explain complex topics so that the nonspecialist can understand it. I frustrated technical writers to tears sometimes (not science but engineering) and that was just part of describing a relatively simple technical protocol.

That is not to say that scientists always get it right, but the peer review process filters out the easy mistakes. If somebody says that they found an adding problem that invalidates thousands of hours of scientific research they are misinformed or lying. There are a lot of people of certain religious bents who have spent most of their lives hoping for the one fact that will disprove 100 years of science and prove their beliefs correct; this attitude has unfortunately spread throughout the US vox populi.

Gordys, was that asset strippers that they banned?

@Gordys - Hell hath no fury ...

By Frito Lay (not verified) on 20 Apr 2010 #permalink

And I asked also today, but nobody answered:( maybe because there is no official report about it, hopefully nothing to report.

'Are we getting any news/feedback of the flights over Europe? Do the current flights prove what the companies have been telling (no risk in the test flights)? Hope the media or companies would not hide this crucial information in order to continue the business.'

Posted by: fire walk with me | April 20, 2010 10:12 AM

By fire walk with me (not verified) on 20 Apr 2010 #permalink

@Frito: No worries. I have taken over your web cam and I am glued to it. I would post the URL here but it would get overloaded in an we have seen happen to our favorite cams in Iceland. Just selfish I guess.

Those how are watching my plots near Hekla. This is not wind, as it is just 0.4m/s now. This the actual harmonic tremor from the eruption you are watching. I did place a link so you can monitor the wind noise where the Hekla sensor is located.

@Gordys you're such a flirt! :) If we're shackin' up, I hope you're rich.

I can't believe I'm watching the little twinkles on the Katla cam. I think I need volcano rehab.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Dear Erik, I am watching this site for the last eight days now(in silence). Love it.great work. I love, that it is so scientifically correct (well,most times). I am a behaviour analyst in the west of ireland (laught out loud at me... but I do love volcanoes, too and how they behave...statistics is fine, but real life is better .. been to iceland a couple of times...) And I am very interested in the behaviour of Our Pet (as a german native speaker I do know how to pronounce her but not good at spelling her name .... Eyafjellajokul ...) and also Katla, which will be our next pet... thanks Erik, for a wonderful site. P.S. they did what I guess was test flights over the West of Ireland,... One plane going south-east and than turning in above Croagh Patrick doing a U-turn. Came back than and did the same again. that was around 20.44 local time.

@Frito: Take your hand off of the mouse and sit back in the chair again...I get by, work for wages and a little investing on the side. Gotta go to bed. The alarm clock goes off in less than 8 hours.

@Tennyson Lee Ahhhhhhhhhhhh. Thaaaaank you!

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Tennyson Lee - Thanks.

@Tennyson Lee - Once again, thank you. I don't know why it's so fascinating - but it is.

There's visible action in the top right quadrant of the katla cam now (where Eyja is)

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Those are tremendous Tennyson - Thank you

@Frito Lay - Have you got the Katla link. I'd be very grateful.


The action is in the area left of the "Almannavarnir" logo

By Frito Lay (not verified) on 20 Apr 2010 #permalink


Look between the "Almannavarnir" and "Mila" logos, then move your eyes to the left :)

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Frito Lay - Many thanks. I see what you mean. There is definately a difference in that area.

Very glad to have the link saved now.

Thanks too, Raving

What is happening on the Katla cam? I can see it but what is it.

Thanks Frito. Saw stuff like that the other night. Not sure if it is light from the eruption or noise floor or what :?

Aurora borealis, maybe?

Possibly the moon reflecting off clouds or snow? It doesn't set there for about another 2 hours. Don't know what direction the cam faces though.

@Austin, I don't think so, but then I've never never seen the northern lights through a webcam :) The location is definitely at EF. All other cams are pitch black though, so it's difficult to know.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

I can see a faint glow or something like that on the top right of the Kstla cam view. It's pretty faint most of the time, but at times it gets bright enough for me without having to block out part of the browser window in order to see it better.

However, I'm not seeing anything on the mila cams as of yet. Maybe that glow could be aurorae or even moonlight? Not sure about the moonlight part right now, but I can see it from where I live (Edmonton).

I once saw shock waves generated by "Survival Research Labs" at a show in San Francisco. An acetylene shock wave canon. They looked like lenses flying through the air very quickly. SRL destroyed old windows with the waves.

One time one hit a bridge support and partly bounced back towards the crowd, it felt like being punched in the stomach. You where warned to wear earplugs for the show, and it was still painfully loud :-)

The energy in those volcanic waves must be incredible to see this over such a large area.

The cam is about 9 km east of Vik. Anyone know where Vik is? lol

By Frito Lay (not verified) on 20 Apr 2010 #permalink

BTW, 'Almannavarnir' is the Icelandic Civil Protection Department, located in the capitol city. They must be cooperating with MILA, who is supplying these images (perhaps serving as as a mirroring site, not sure). Their logo showed up on the vid marquee alongside MILA only after the images were restored after the vid outage the other day.

The public service benefit in providing access to the streaming images from MILA stretches out to those of us near and far who are dutifully monitoring the volcano around the clock.

We here at Eruptions, in turn, are providing casual and technical commentary to many, many quiet lurkers who tune into this weblog daily to catch up on details and informational links. Some of those lurkers are technical professionals and government agency officials, guaranteed.

Every little bit helps, when you are on a tight learning curve.

Thank-you, Almannavarnir.

Looks to be light reflected upwards

I took several minutes worth of video from the Katla camera, stacked the images every 2 seconds, and then did some photoshop enhancement to get this:

I still don't know what the glow in the sky is. It could be high clouds in moonlight or the aurora. But whatever it is, you can see it much better now. ;)

By Benjamin Franz (not verified) on 20 Apr 2010 #permalink

@Benjamin Thank you. Whatever it is, it certainly kept us amused for the past hour :) The sun should be coming up soon and I was hoping to see more then, but I understand it's going to be another bad weather day.

By Frito Lay (not verified) on 20 Apr 2010 #permalink


@Scarlett #226 - how do you get "Leading vulcanologist questions why flight were grounded for such a small eruption" from that article?

By Frito Lay (not verified) on 20 Apr 2010 #permalink

226: You obviously did not read the article. Nothing of the sort was said by any of the volcanologists interviewed and quoted.

FVXX01 EGRR 202327

DTG: 20100421/0000Z
PSN: N6338 W01937
ADVISORY NR: 2010/028
OBS VA DTG: 21/0000Z


By M. Randolph Kruger (not verified) on 20 Apr 2010 #permalink

@Benjamin #223

Maybe it's the glow coming from Reyjkavik. If I'm not mistaken, that's also in that direction?

Absolutely nothing visible from the volcano on the Hvolsvelli webcam tonight, except the near and midfield lights from farms and road. No reflected lights, no stars. Overcast?

Webcam is now disconnected.

Re the comment at 226 - I agree, I don't see anything in that article that implies any volcanologist thought that. Please do not spread misinformation like that.

I've edited the comment at 226 to make sure no one misconstrues that information. Sorry if that offends anyone - I'm not going to take it down, but I'm making it clear that the article linked doesn't say anything of the sort.

@Benjamin (223) and @ Meteo (231) That can't be noctilucent cloud as they can be observed from mid May to August, now the conditions are not proper for it at all.
The caouse of the light migh also be the setting Moon seen through the clouds.

@Everyone :) I've seen the terms "vOlcanologists/vOlcanology" and "vUlcanologists/vUlcanology", etc.

What's with the "u" I see sometimes? I thought that was only Star Trek-ish stuff? Can someone please clue me in? Thanks in advance.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Could it be that it has to do with sunrise? We've been seeing this every night, starting at an earlier and earlier time. (The moon is waning, and probably can't be seen thru clouds). I know the camera is pointed west, but could it be higher clouds that are reflecting the sunlight?

Hvolsvelli webcam is now visible. (yay!) Ãórólfsfelli is black. Valahnúk is black. Mulakot is black.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@236: error likely due to Vulcan, the Roman god, and not Star Trek.

Vertical tremor plots look like they may be inching back up again. Let's see if we get an answering response on the EQ map.

@Austin. Thanks. Must be scarlet fever ;) I've wondered recently how many post here from different nics are actually from the same person. The devil is in the details.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Erik Klemetti, 234, you have such a light hand with this blog that no one should be upset with your edit. "One has a right to one's own opinions, but not one's own facts";-)

Taco, 236, My guess is the vU writers write their excellent english as a second language (Vulcan as the root, as noted by Austin).:-)

@Frito Lay (236) Many languages use the old Latin form of the word with the letter U not O. Maybe those who write vulcan, etc, might have a language of these.
English is the exception :-)
(German: der Vulkan, Polish: Wulkan, Italian: Vulcano - etc.)

@Frito: It's a legitimate mistake - I've never understood why we use an "o" sometimes (volcano, volcanologist) and a "u" others (Vulcan, vulcanized) when it's all from the same root.

But sometimes trying to understand English is as difficult as understanding Icelandic :)

@Monika, parclair (lol <>taco? I'm a corn chip!), Austin,

Thank you! I've learned more here in 6 days than I have in the last 6 months. :)

By Frito Lay (not verified) on 20 Apr 2010 #permalink

>I'm a corn chip

Do you leave crumbs on the keyboard when you type?

@Passerby - No, i would want the mess so I collect all my crumbs and, when the jetstream is just right, I suspend them over a just-recently shaken can of pop and ... ;)

By Frito Lay (not verified) on 20 Apr 2010 #permalink

NASA/JPL Terra Satellite ASTER (Advanced Spaceborne Thermal IR Emission and Reflection Radiometer) webpage, constructed by Michael Ramsey, has compiled day- and night-time images of Eyjaf for your viewing pleasure.

Jon's recorders seem to show a slight uptick in tremors.

Noun1.vulcanology - the branch of geology that studies volcanoes

@Frito sorry I misread this statement ""It is kind of amazing. I imagined this in a big eruption. I didn't imagine it in a small eruption," said John Eichelberger, head of the U.S. Geological Survey's Volcano Hazards Program, who is stranded in Paris, where he had attended a meeting on volcanoes."

as I had just read this section ""The eruption that's going on right now is small in comparison to what we expect Katla would be like," said Jay Miller, a volcanologist at Texas A&M University. " then skimmed over to the other part, my mistake...

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

@passerby and scarlet pumpernickel, thanks for the interesting links.

@Scarlet Pumpernickel - It's not me you need to direct your apology to, it's Erik and this community. I suggest you post an apology to @Everyone.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Frito Lay (#236) and following: It's vOlcanology and vOlcanologist - although through the 1960s you'd find the occasional "vUlcanology" even in the scientific literature.

Re the question of volcanic tremor (#164, #167 etc). Volcanic tremor is a signal that is produced by movement of magma and movement of gas (e.g., in a magma). It is not all that easy to interpret. It can mean that magma is close to the surface and emitting a lot of gas, kind of bubbling, but not really erupting. It can mean that magma is indeed erupting. You have to look at the spectral (frequency) content on one side, and then you ought to have also a way to locate it, so that you can see where the actual source of the tremor is. We have no way seeing the source at Eyjafjallajökull on the internet, and you have no way seeing the source at Etna because the data are kept internal (this is because they can lead to wild speculation and happy misinterpretation if rendered public).

Talking about speculation. This site is currently receiving enormous attention by all sorts of visitors over the world. You can be most certain that if someone declares here that something dramatic is about to happen at any one volcano, this is going to make it into the news (see the Hekla example two days ago). That's why I am sometims very cautious in voicing alarmist statements, especially if the available data is incomplete.

As far as I understand this, Icelandic volcanologists, civil defense and authorities, since many years have collaborated to set up an emergency response plan for Katla and Eyjafjallajökull, in order to be able to react timely once things were getting tense. That's exactly what has happened. They were ready when the eruption started - maybe no one really knew how it would develop but they were ready for whatever scenario and that's the big point. Often we cannot say how an eruption will be even when it has already started. But this can be compensated with good preparedness and prevention.

There was much less preparation and prevention as far as European and intercontinental air traffic is concerned. Iceland's prime minister is doing a hell of a good job in saying this was only a "small rehearsal", because indeed one day a much more serious eruption will happen.

Ãórólfsfelli's visibility is nil except for the bottom
Hvolsvelli shows a beautiful morning but EJ isn't visible
Valahnúk's view ... well, it still reminds me of Monty Python's Bridge of Death scene. Is it just me? :)
Múlakot airfield is clear but overcast.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Scarlet #250 So now you're pushing the idea of a possible tsunami? Two posters (or one poster under two different nics) tried that here few days ago.

Thank goodness most people here are on to you.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

I had already signed out for the evening, but then noticed the entry in the Robert Brown blog on global warming and volcanism. While somewhat interesting I then made the mistake of perusing its comments section. This disturbed me so much that I had to scurry back to Eruptions, which by comparison is a bastion of rational thought and civilized discussion. Thank you all.

The Katla cam at is up, but you can't see anything of Eyjaf itself, except for a glimpse of its eruption column from time to time.

"small rehearsal"

There are a variety of disasters, be they natural, man made, expected or unanticipated that involve response, co-ordination and public preoccupation which is similar to a volcanic eruption.

This eruption in Iceland reveals that preparations for such events run the gamut from good and measured to chaotic to nonexistent.

#257 I'm just saying that people's memories are short and over geological time things can happen. It was an interesting article that I found about a previous Tsunami in UK a long time ago. "The continental slope of the Norwegian Sea is still unstable."

"The 1931 Dogger Bank earthquake, in the southern North Sea, had a magnitude of 6.1 and caused a tsunami that especially hit Britain. "


The three-time Formula One champion, who now heads budget carrier FlyNiki is very upset about the closures.…

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

There has been a lot of speculation in the media wether there is a connection or not between Lady Eyaf and her big sister Katla.

I would like to ask you guys who knows alot more about the mechanics than i do if this might be true:

There are two volcanoes within close proximity of eachother. Eyafjallajökull which historically has set off Katla on 2-3 occasions.
Can the reason be related to inflating / deflating?

What I mean is that during the quiet years both Eyafjalla and Katla inflate due to increase in pressure from the magma reserviors
beneath them. Now that Eyafjalla has erupted the pressure releases and by logic it should deflate right? And since Katla has not
erupted it should by the same logic have more strain due to the deflation of Eyafjalla (like a rubberband between Eyaf and Katla).
And the magmatic pressure continues to build beneath Katla until she blows her top. And then she calms down and Katla deflates
back down to "normal" levels and settles right beside Eyafjalla.

This is just a theory i thought of and I might be dead wrong. I realize that there might be other factors involved also as elevation of
the two, if they share "plumbing" or not and so on...

But if Eyafjalla´s reservoir is more shallow that Katla´s then that would explain why Eyafjalla blows first and Katla a while after due
to increase in strain.

Just my 2 cents..please correct me if im wrong..:) Im here to learn..


Regarding my 226 post - I just like to say that my wording didn't mean to mislead, I was just summarising it quickly and chose the wrong wording, and the vulcanologist just said he was surprised that the amount of airspace closure that occured in a small eruption. But he did say he was surprised with the amount of closure of airspace with this eruption. Just wrote the wrong words to summarise, I should have said he was surprised to see such a smaller type of eruption have so much effect.

My apologies.

see below from article

"The lengthy shutdown of many European airports continues to surprise travelers and scientists. "It is kind of amazing. I imagined this in a big eruption. I didn't imagine it in a small eruption," said John Eichelberger, head of the U.S. Geological Survey's Volcano Hazards Program, who is stranded in Paris, where he had attended a meeting on volcanoes. "

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

I goofed earlier. In checking my map, Katla cam points north. The glimmer we see is on the right (east). So, I'm even more sure we're seeing sunrise on the Katla cam (I/m pretty sure someone else suggested this the other day)

"Old Faithful Geyser, Wyoming, is a converging-diverging nozzle in which liquid water refilling the conduit during the recharge cycle changes during eruption into a two-phase liquid-vapor mixture with a very low sound velocity. The high sound speed of liquid water determines the characteristics of harmonic tremor observed at the geyser during the recharge interval, whereas the low sound speed of the liquid-vapor mixture influences the fluid-flow characteristics of the eruption."

What can you make of this? It is from an article I read here.

The site only gives an abstract of the entire article. You can pay $25 for the full piece if you want it. I didn't write it.

Looking at these graphs on the site there seems to be a correlation. Any ideas?

@Scarlet (#263) - just a quick note (referring to my earlier post #255), it's "volcanologist" not "vulcanologist", like "volcano" not "vulcano". No apologies due this time :-)

Regarding the Katla webcam:

It is probably a low light camera. It is probably set up with public access as part of the civil emergency response.

I read that the town of Vik has practiced an emergency evacuation to a shelter within 30 minutes of an alarm.

Although 63 deg N. is below the Arctic Circle,there is still an extended period of twilight between a late dawn and early dusk.

Vik is a spectacularly beautiful place. Sigh.

@Boris - you know whats doing it, it's the spell checker in Firefox, it puts vulcanologist as ok and if I put volcanologist in, it comes up as a spelling mistake lol. So that's I think the source of this confusion. I think the problem comes from the island of Vulcano which I'm sure you know well? I still have a smelly shirt from it I can't clean!

By the way, what are your thoughts regarding volcano lighting. It seems to be a bit of contentious issue, is the earth more "plasma electrical" then we think? There seems to be some problems with comets as well… is the earth more electrical in some way then we understand yet, or is it really just the particles causing the lightning? There are also the occurrence of reverse lightning as well! (very interesting this video!)

Some other links…!C00F2616F39D0B2B!152.entry

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

@Parclair - The Katla cam at Vik does normally point north to Katla (go figure) but the last few days it has been oriented towards EF (more to the west).

I'm not sure if they changed it back but the screen subscript still indicates it's looking at EJ.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

Can I just say that I have a very healthy repect for Volcanologists and Geologists both who are on this site and practising in the field. You guys and ladies must have been extremely busy over the last week and I salute you all.

It's very easy (but not warranted) for lay people to knock the specialists. But please be fair when thinking about your comments on this site. We live in an ever shrinking global community (reference to technology not geology) and this site I regard as an intellectual site and not an everyday twitter-type site where you can freely knock who ever you want.

Thanks to everyone for providing such interesting insights- you've got me for life. Particular thanks to Eric and Boris- well done guys!

"Old Faithful Geyser, Wyoming, is a converging-diverging nozzle in which liquid water refilling the conduit during the recharge cycle changes during eruption into a two-phase liquid-vapor mixture with a very low sound velocity. The high sound speed of liquid water determines the characteristics of harmonic tremor observed at the geyser during the recharge interval, whereas the low sound speed of the liquid-vapor mixture influences the fluid-flow characteristics of the eruption."

What can you make of this? It is from an article I read here.

The site only gives an abstract of the entire article. You can pay $25 for the full piece if you want it. I didn't write it.

Looking at these graphs on the site there seems to be a correlation. Any ideas?

@Allison (270)

A brief interruption in god's data feed. :)

@Doug mcl (#185). One of the reasons scientists come croppers is because they - as a group - are notoriously bad communicators. Before I go on, there are exceptions such as our host Dr Erik Klemetti, Dr Boris Behncke and other "Eruption" readers.

The first mistake scientists generally make is that they seem to think that it is the listener's job to understand, not theirs as specialists to explain in an understandable manner to an audience that does not have the benefit of their education and, often, lifetime of experience in the field.

Second, as a group scientists seem to give the impression that they belive it is the journalist's job to explain and interpret to their listeners what the scientist said. It is not. The journalists job is to report and, unlike scientists, they are rather good at getting their message across. But if the message from the scientist is garbled or gobbledygook or open to misinterpretation, it's not the journalist's fault - do not blame them for being irresponsible when the failure is yours!

Third, many scientists give the impression that they use all those fancy terms of their profession just to impress, not only John & Jane Doe, but also, their peers just how clever and learned they are!

It is my opinion that a substantial, must-pass, course in communication and education should be an obligatory part of every post-graduate course. That said, there are a lot of bad journalists out there who seem to think, aided and abetted by their equally bad but also irresponsible editors, that their job is to interpret every news story for the benefit of a certain political ideology or agenda.

If we could get to the point where scientists are professional communicators, able to explain in a manner easily understandable to the layman (Constructivism, Piagét & al), the irresponsible, political agenda-orientated journalist would have less scope for her or his shenanigans!

James, it is indeed a pleasure to read your reports on the Grapewine, well done sir! I do hope you go on and have a distinguished career in science, not journalism!

Henrik, you are a big optimist.

"If we could get to the point where scientists are professional communicators, able to explain in a manner easily understandable to the layman (Constructivism, Piagét & al), the irresponsible, political agenda-orientated journalist would have less scope for her or his shenanigans!"

I'm a scientist myself and over the years I have encountered colleagues (incl. bosses / mentors) who explicitly instructed us younger ones not to 'over'-simplify whatever we were discussing, just because 'uninitiated' lay people might try to understand.

Obviously, I whole heartedly disagree with those 'instructions', but I've also encountered enough situations were it was beyond my ability to get important points across. Sometimes people don't want to listen or don't want to believe what is said (for various reasons). Sadly, these 'people' are as often as not the journalists we might talk to to publicize our latest findings...

It clearly is a challenge how to communicate with the lay public about ones findings. Often the scientists (myself included, of course) don't grasp were the disconnect in the communication happens and that's not helpful either...

(Sorry for rambling a bit...)

It has not so much to do with communications as it has to do with sloppy science. Take for example in the climate area. In California in the 1960's there were dozens if stations in all climate zones reporting data. Today there are four stations that report the data for the entire state. All four stations are on the coast. There is no data from the mountains or the central valley or the Eastern Sierra included in climate surveys.

Now take into consideration the recently discovered fact that the sign is often incorrect on reported data (temperatures below 0C are reported as above 0C) and an earlier discovery that sometimes a monthly mean is repeated in that sometimes the previous month's mean temperature is reported as the current month's mean.

So we have a situation where the data can not be trusted. If the input data can not be trusted, it follows that decisions derived from those data can not be trusted.

And note because of the nature of the mistake in data reporting, positive data is never misreported as negative, only negative misreported as positive. This leads to a warm bias in the data. If you have a location that is -30C and the temperature is reported as 30C, that is a 60 degree error, and it happens all the time and it is documented.

It is because of the new METAR format. A negative temperature must be reported with an M (Minus) prefix. So -30 is reported as M30. A report entered as -30 is reported as 30, the - is ignored. So mistakes at stations in data entry result in great skewing of climate data and this skewing only occurs where there are temperatures below zero and where temperature are greatest below zero is where the error is greatest.

@GeorgeR (#190). It's a general misconception that the task of science and scientists is to "find The Truth" for the benefit of the general public. The job of science and scientists is to observe and formulate hypothesii ("theories") that explain observed phenomenae better than previous ones do. This is why the general public get the impression that "scientists do nothing but disagree about things no one has ever heard of that costs outrageous amounts of "their" money and is of absolutely no practical use to anybody."

With applied science a.k.a technology it is another matter. Once scientists have agreed on a theory that explains all hitherto observed phenomenae, there may be useful applications such as microwave ovens or predictions of imminent volcanic activity. However, people who invent useful applications or predict future volcanic behaviour are not scientists as such, but rather highly trained professionals who by neccessity have to have a very thourough education in science and be able to use the theoretical tools of the science in question.

Did I just call Dr Boris Behncke a technician and not a scientist? No! Dr Behncke and his colleagues are in the field of applied science where they use well-established and proven scientific theories such as plate tectonics to interpret observed data to formulate hypothesii of how Etna will behave in the immediate future and quickly find the most likely one in order to be able to issue timely public warnings. In order to do this efficiently, he and his colleagues at INGV have to be even more scientific than their colleagues in theoretical science who are not fettered by the consequences of a badly formulated and scientifically unsound hypothesis.

Henrik & Holger (#273, 276). There you're touching a very critical issue. While "public outreach" (that is, communication with the public) is gaining importance in the repertoire of scientists (certainly geosciences, which is the sector that I can competently refer to), many colleagues still struggle or sometimes straightforward refuse to make some effort in that direction. However, in recent decades much progess has been made, and I see that also our institute is dedicating time, resources, and effort into communication with a public that needs to be informed (the population of Italy, which has to face a number of geological and meteorological hazards). One outcome is the "INGV terremoti" video collection at Youtube (

One reason why many colleagues still refrain from giving all they can in public outreach is that it requires virtually as much time and effort as the purely scientific work. For me it is an immense pleasure, because (1) it's about a fascinating subject and I love sharing what little experience and knowledge I have in it, and (2) I personally feel morally obliged to share and do this in the most accessible way there is. But it is true, most of the comments I post here take up to 30 minutes to write in each single case. So sometimes it's just a question of time, and I fear my contributions here will be reduced once one of our volcanoes here in Sicily will act up, Etna being likely to erupt within weeks to months - and then they will be mostly updates on things going on here.

My heartfelt thanks to everyone who has expressed her or his appreciation, it makes me feel the message is getting through.

I am not an expert but let me try to explain in my own laymanâs terms why you wonât get a clear answer to whether Katla will blow because of this eruption at EyjafjallajoÌkull or not.

It is quite likely that each of the volcanic centers in Icelandâs EVZ is composed of multiple channels and multiple chambers, some interconnected and some not. Possibly this maze is complex enough to extend into interconnecting systems which MIGHT be the case at Katla and Eyja, but this is only conjecture and not firmly established. To make it more complicated, not all of the magma in these systems are even liquid. The magma is frequently in a state known as a crystal mush that barely moves until some parameter is passed (like an injection of hot fresh basalt from below or a tectonic movement eases the pressure). To complicate things further, the nature of the magma in the various chambers, dikes and sills often differs from each other. This is why even the one volcano will erupt in different ways, sometimes at even the same time.

So it is not simply a case of establishing a connection in the plumbing of the two volcanoes (which nobody has yet done), you also have to show that activity at one center acts a tipping point in changing the eruption parameters at the other center. This is hard enough even in one system. Take this two phase eruption at EyjafjallajoÌkull for example. The eruption could just have easily ended after the basalt fissure eruption at FimmvoÌrduhals, or the fissure eruption could have gone on for months, without it tipping the more evolved magma under the crater towards eruption as it did. And Katla is even more removed. So it is very hard to make any kind of statement on the impact of this eruption on the Katla system.

That said, postulating a wider regional tectonic impact from the deflation of Eyjaf is an interesting conjecture. I am sure Boris would be able to give us some examples of volcanoes erupting in close proximity to each other where this might be the case. However this all might be, I think we can also expect to see seismic swarms under Katla that would indicate a response to such stress if this were the case. And this would be a first step, even before magma started moving in the system.

By bruce stout (not verified) on 20 Apr 2010 #permalink

Another part of the problem is with the nature of personalities involved. Scientists tend to be of the prima donna sort in many cases so there is a lot of walking on people's eggshells when it comes to official conclusions in scientific matters.

@Henrik Another excellent post. You never disappoint :)

The fundamental rule in communication from time immemorial has always been: the person who has the message to be communicated has the responsibility to communicate it.

That means no one should have to go looking for it.

Once done, if the listener doesn't understand the message (if there's any ambiguity), it's their responsibility to ask for clarification. Irresponsible listeners disseminate or act on their misunderstood message after filling in the blanks themselves.

*Sigh* I could write a book.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Hasis - Thanks Hasis, chap 2 is a great read!

By Scarlet Pumpernickel (not verified) on 20 Apr 2010 #permalink

I am not going to get into the climate stuff, but as a mathematical physicist, these days I am continually shocked at how many professional scientists seem confused over scientific methods.

To give a real example from a few years back I got into an argument over...we are off to Greenland to measure temperature increases. When I pointed out that it should be temperature changes, they still didnt get it. It sounds pedantic but there is a huge and fundamental difference there.

More recently I saw a board of distinguished scientists formed a commitee to decide what finished the dinosaurs. Now what did or didn't is not the point. The point is that science cannot be done by comittee. Things are either probably right, probably wrong or unknown. Emphasis on PROBABLY. Getting a committee to decide the truth...why not a vatican council like it used to be done? Madness, and worse nobody can even see the fundamental problem.

And to finish my little rant, a good scientist is never certain. It bothers me to see scientists not understanding that issue. Certainty is something for preachers. As soon as a scientist is certain of something, then that implies they know everything and case closed. We may as well all pack up and go home.

Agreed though that poor communication is a chronic problem, but rather than turn science courses into everything but science courses, I would rather see more science than a lot of the wishy washy stuff done these days.

Fundamental science has been hammered in the last two decades with an emphasis on the applied. So eg. knowing volcano names and terminology is one thing, but without good basics in geology, chemistry and physics it is stupid. (Not picking on any specific field here.)

Whole generations of scientists are now being churned out without a clue on scientific methods and basic statistics. I could go on about poor science, politicisation and general dumbing down - but will go hide now.

Ãórólfsfell web cam now showing gaps in the cloud. White vapor coming from the volcano, virtually no ash. Which is a good thing, as long as it will go on like this ...

@ Dylan Ray

that is merely the exit point from under/beside the glacier where melt water has been exiting. It has been constantly changing over the course of the eruption.

By bruce stout (not verified) on 20 Apr 2010 #permalink

black lines forming on the top of the glacier on Poro...ay ideas what they are?

Frito Lay, thank you, but I am afraid that to many, I may have broken down already open doors. It is good to see Holger, George and Boris take it in the spirit intended, thank you!

Another interesting facet of science that has implications on the matter at hand is the Paradigm theorem of Thomas Kuhn. Briefly for those who've never heard of it:

According to Kuhn, science progresses in leaps where a system of thought is established as being "True Science" such as the Newtonian Physics of the 17th-19th Centuries and all further understanding is limited by what is possible under that theory. Kuhn calls this the paradigm. However, there are inconsistencies and in order to explain those, what Kuhn calls ad-hoc theories are inserted as props to the main theory. With time, the props become so many that the main theory collapses under its own weight and is replaced by one brilliant intuitive leap such as that provided by Einstein. Kuhn calls this a paradigm shift. For a time, the new theory not only explaines old observations better, but many more new insights are gained. Then inconsistiencies begin to appear, new ad-hoc theories are added etc

One of the main problems of science is education which by necessity has to be within the current paradigm and also usually not by the brightest minds, people such as Stephen Hawking being the exception rather than the rule. Students are taught to repeat the thoughts of the exisiting paradigm until it is thoroughly ingrained. As Professor C Northcote Parkinson says "Dim men elect dim men".

The net result is that many faculties become expert at producing trained monkeys incapable of genuine thought. They are very good at repeating, often verbatim, the lessons learned and are notoriously reluctant to use terms that other people outside the initiated could understand because this would reveal how shallow their own minds are. The hallmark of an intellectually adequate mind is that the owner has no hesitation in admitting how little he or she really knows and readily explains what she or he knows in terms as simple as possible.

Seems there's a bit of renewed phreatomagmatic/surtseyan activity (started at appx 0843GMT)and it's slowly increasing. Nothing on the scale of last week-weekend though.

@Henrik, quite honestly, these past few days I've seen (self-identified) "seasoned" volcanologists trample any kind of paradigm shift.

The very public dressing-down of Jon Frimann not once, but twice, in the past 24 hours by someone who claims he was "just like him" until he got a plumb job in Italy said more about this self-proclaimed expert than it ever will about Jon.

From what I've observed, Jon is certainly no trained monkey (thank God), and has been more accurate in his postings than anyone here.

@George: you really need to find another hobby if all you can do is throw blanket accusations about "sloppy science" day in and day out.

By Frito Lay (not verified) on 20 Apr 2010 #permalink

@Henrik: Where do you see this?

Hvolsvelli and Thorolfsfelli cams. Initially there was a thin gray-black plume to the right plus a larger grey-white to the right, well-separated, in the Thorolfsfelli cam which blended to one in the Hvolsvelli cam.

There was a crack that opened on the glacier on the poro cam from around 1/3 of the way up, down the LH side to the base moments before this activity. Is it possible that the magma has mad its way into the glacier which is feeding this activity? Te front of the glacier looks quite unstable.


Thanks for a brilliant site - have learnt much in the last few days about the subject.

Firstly let me say - that when it comes to the Climate, I am in the "somewhat sceptical" camp (little off topic I know, but there is a connection).

The real truth is I don't know, but I can sense when the communication is going wrong, and that has been my perception w.r.t. the climate debate.

The points you have raised w.r.t. communication are crucial and it is never a simple binary right/wrong. This is certainly true of the area I am more familiar with - software engineering, where you try and do your best using well worked processes. One of the reasons that the processes are there (similar to peer review) is that I have 100% faith in my (and my colleagues) ability to make mistakes. Therefore proper planning/testing is crucial to make an end product that approximates to the original requirements.

I have also worked (quite recently) in a "high pressure, dynamic target driven environment", where the impression was that if you paid enough money and applied enough pressure you got the results that way - and if mistakes were made - you fired the person and got someone else. Needless to say, that environment never got the result it desired and left a lot of demotivated staff who were simply afraid of making mistakes - therefore losing the critical edge of their abilities.

The thing is - I see a lot of similarities in some of the scientific discussion esp w.r.t. climate, and I guess in the next few days w.r.t. meteorology and prediction of dust dispersion etc. etc.

It is crucially important to emphasise the search for truth/facts at the same time realising that the problems we are dealing with are multi-faceted, and that means having the humility to accept that no one person/instution has ownership of truth.

One of the reason I like the discussion here is that you are very openly sharing your observations and experience (among the great unwashed of which I am one ;) ) while at the same pointing out both the limits of your knowledge and some of the essential variability of the systems you are attempting to describe. This differs substantially from the "overwhelming concensus" message that is being displayed elsewhere.

thanks again for a very informative blog/discussion.


By John O'Connor (not verified) on 20 Apr 2010 #permalink

@ Frito,

please don't start knocking Boris as I think this is totally unwarranted.
He did not give Jon any public "dressing down". He merely reacted to a comment Jón made where Jón expressed his frustration with the official Icelandic volcanologists for what he saw as downplaying the potential risks. Boris was not only fair in the way he did this, he also pointed out the huge difference in position between paid public officials and pundits like us on a website who are accountable to no one. He certainly in no way disparaged Jón's acumen or contributions here.

By bruce stout (not verified) on 20 Apr 2010 #permalink

@Frito Lay (#296). While I wholeheartily agree that Jón has been uncannily correct in his predictions so far, I cannot agree with the rest of what you say. Jón's latest prediction of a much larger blast is - unlike his previous predictions - not corroborated by the available evidence. IF something bigger was on the way, we would expect to see inflation - not deflation - of the mountain as well as the harmonics. Future events might very well prove Jón correct and if so I'll be among the first to say "Good on ya cobber!"

Now, from what I gather, Eyjafjall has behaved in a manner that deviates from the norm for Icelandic volcanoes in general and it's own behaviour in the past (at least what is known). For my part, I interpret what you see as a "public dressing-down" as a combination of Jón expressing himself in a manner wide-open to misinterpretation and Dr Behncke reading it as self-congratulatory criticism of the Icelandic professionals. Although I can see and empathise with both sides, I think both Jón and Boris will agree that it was a misunderstanding where both parties are equally at fault, if there indeed is fault!


@Bill.G Bear in mind that the bottom of the glacier is currently surrounded by snow. The tongue of the glacier is actually quite small here. What may appear to be a crack in the ice could just be a stream melting the snow over mud.

@John O'Connor (#300). Thank you, but this is a community where each and everyone contibute to our mutual erudition and intellectual pleasure. Thanks should be directed at Dr Erik Klemetti, our host, who has made this possible.

The process you describe reminds me very much of a phenomenon oh-so-common throughout human history (I majored in History) - whenever the augur/shaman/priest/scientist does not provide the answers the Chieftain OR the tribe desires, someone who does gets the job instead.

.. another thing, it has been great fun following this eruption from the early days and all of us having our own pet theories and discussing them amongst ourselves. I haven't had such fun playing around with ideas since my university days.

However, if this whole experience has taught me anything, it is how complex volcanic systems are and how fraught with danger ANY prediction is. Shortly before the Frimmvorduhals eruption I think it became obvious to most of us that there had been a subtle shift in the seismic activity and we were getting close to an eruption. It was certainly no surprise to anyone when it did erupt. But what kind of eruption, it turns out, was extremely uncertain as later events have proven. Sure, there is always a chance that something bigger is on the way. But I would hate to be in the shoes of the authorities having to make decisions on when and how they communicate these risks.

Basically the general public should be aware that there are risks, just like with the weather, and they should be able to make their own choices on the basis of that information. Where, however, public policy has to take life or death choices, or individual choices result in similar risks for unrelated people, the officials MUST err on the side of caution simply because that is what the public expects from them.

In New Zealand they pulled down some great old buildings because they were not up to earthquake standards. Sometimes I wonder why there aren't prohbition zones in a similar fashion around active volcanos like Vesuvius or Etna. Maybe its because we hope a volcano will give us enough warning to get out of the danger zone in time. Maybe because it's just because its cool living on a volcano. I don't know. What's certain is that Europe needs to work on a few contingency plans.

By bruce stout (not verified) on 21 Apr 2010 #permalink

Once again I'm impressed by the level of professionalism (generally) in the discourse here, particularly in handling the multitude of queries, theories, OT remarks, and random notions of us amateurs and dialogue-watchers.

I spend so much of my time here in Afghanistan trying to raise the game of the Public Health "professionals" who are supposed to be my colleagues and peers. These Afghans have a tendency to publicly belittle those who offer any glimpse of less-than-full-knowledge compared to the others 'round the table. It's disheartening and you can see why the country's development as a whole (and its emergence from open warfare/hostility) will be stifled for another decade or two. These are PUBLIC HEALTH folks, after all, not military strategists or tribal chieftans...
They really seem determined to keep a tight grasp on their over-simplified view of expertise and authority.

Just a THANK YOU to Dr Klemeti and Dr Behncke et al for the inputs and feedback in this arena.
I've been learning a lot minute by minute.

By Matthew UK/Afg… (not verified) on 21 Apr 2010 #permalink

Where does Eyafjalla stand on the VEI scale? 2-3? How much tephra has been ejected? Anyone that has seen some numbers so far or is it too early to tell?

@Jamie.Z Jamie I watched the crack appear for over about a dozen frames. At one point it runs slightly up the side of the mountain on the left. It has opened considerably since.

@bruce stout I disagree. Boris has lectured everyone for several days about not making public statements, yet he chose to embarrass Jon publicly instead of taking it to email. Jon is not a "paid public official" so Boris' advice about shutting up lest he be sued, etc. was bizarre to say the least.

@Henrik I hope both Jón and Boris have a group hug someday soon if they haven't already. Regardless, when I saw the dressing down of Jon's post (which was not wide open for interpretation - it went straight to the point) it struck me as an attempt to publicly shame him for embarrassing those who should be in the know. Perhaps that's why Boris became so vehemently defensive? Who knows.

Regardless, I haven't seen anything Jón has said that has been more wide open to interpretation than what Boris has said on here, by far. I've been surprised several times when reading Boris' posts where he pretends to calm the waters, only to come out with his own Etna-derived conclusions about EF that, yet again, set the news wires abuzz.

"Paradigm shifts"? Please. People in every discipline have seen the fancy presentations.

It starts on the ground.

By Frito Lay (not verified) on 21 Apr 2010 #permalink

I agree with Jamie. Are you sure you are not just looking at water cutting a channel on fresh snow? I presume you are referring to the Porolfsfelli cam and the "cracks" are running each side of the glacier? Or are you seeing something higher up on the mountain?

OT there's a fair bit of ash getting thrown up at the moment.

By bruce stout (not verified) on 21 Apr 2010 #permalink

Daniel! (#307) If you scroll down here, you will find some figures
VEI 3 corresponds to 0.01 cu km DRE (Dense Rock Equivalent), VEI 4 to 0.1 cu km DRE. As you see, the figure given is 140 million cu m (0.14 cu km) uncompacted for the first 72 hours of the current, main, eruption. Dr Behncke on an earlier topic said that 140 million cu m uncompacted corresponds to a DRE of ~80(?) million cu km.

@Frito, well this is at least interesting in its own right for being a prime example of how two people can have totally opposite interpretations of one and the same thing. I didn't see it like that at all.
But I don't want to further any discussion on personal/political issues as this site is great for being relatively free of such crap so far, so let's just both drop it and respect our mutual rights of holding our own opinions. You ok with that? (If not, you can email me at
But, let's just get back to talking about volcanoes, ok?

By bruce stout (not verified) on 21 Apr 2010 #permalink (Etna)

My question is, doesn't Etna have big plumes, but the planes often fly around, you don't see the whole middle east closed down all the time, I remember I landed in Catania and we could see the plume of Etna, it's only if the ash practically fall on the airport that they close it? Is the ash not as bad from Etna because it is not glacial mixed?

By Scarlet Pumpernickel (not verified) on 21 Apr 2010 #permalink

Which in turn would mean that she has access to a new source of water?

@Daniel, looks like it. There may have been some slumping of ice into the vent. It doesn't look like a new vent as I think this would put up a much higher eruption/steam cloud.

By bruce stout (not verified) on 21 Apr 2010 #permalink

@Hasis I think when you see a website calling his book a "denier book" I think it has problems, that's not science anymore, he's book is completely full of references. So he's also anti-creationist as well because he's not religious it that a conflict of interest too :P

I think "Climate change" is a 14metre rise in sea level, not 1mm :)

A lot of geologists work in mining, they need to be paid somehow.

By Scarlet Pumpernickel (not verified) on 21 Apr 2010 #permalink

Scarlett Pumpernickel has 10 seconds to dodge incoming meteorite!

;-) Hey, maybe I should work for the Daily Mail!

By bruce stout (not verified) on 21 Apr 2010 #permalink

SP: Plimer's book being full of references is a smokescreen to fool the gullible and uninformed by presenting the appearance of respectability. When one actually checks said references, one finds that he is cherrypicking data, distorting and occasionally simply lying. His arguments have been shot down by many people in multiple countries, now, but like Andrew Wakefield and the anti-vaccinationists there is always a lay public who like the sound of the "brave maverick" standing up against the "mainstream conspiracy", who continue to believe in him in the face of all the contradictory evidence.

Plimer started out well, but he has shredded his own scientific reputation; he relies on fame amongst non-scientists to keep him going.

More details linked at Desmogblog:

By Luna_the_cat (not verified) on 21 Apr 2010 #permalink

Helicorders are picking up some increased activity. Wind speed is stable so it has to be mostly seismic. And water flows seems to be increasing judging by the picture (i might be wrong)..And there seems to be a big steam cloud rising on

I want to point out one thing. My perditions are not always correct. Because the nature of them is like forecasting the weather (that is where I base my idea from). But with more data, the better prediction I can get.

Deflation that we are currently seeing does not mean that there cannot be a big explosion in Eyjafjallajökull. That possibility did show it self few days ago, and it is still there and it refuses to go away. But I do not have any time scale for that, not now and possibly never. The thing is that I need to put a lot more work on the time scale side of thing, the rest is getting a long nicely. I should be ready to write something about it in 10 to 20 years time.

Today the ash cloud is getting darker, but that is interesting in it self. I am expecting to see a surge in activity soon in Eyjafjallajökull. But when is a really good question with no answer at the moment.

I am expecting the explosion to be close to end of the eruption. Like what did happen in 1821 to 1823. But it remains to be seen if that happens or not.

There also appears to be a stable magma source inside Eyjafjallajökull at the moment. So this eruption is not going to stop any time soon it seems.

am watching the Ãórólfsfelli cam.. are those fissures around the snout growing?? or is it just my eyes seeing things??

Jon, I was island-hopping in the Caribbean with my wife a few years ago and we spent a couple of days on Montserrat. The volcano hadn't erupted in 6 months and there was nothing seismically happening to indicate an increase in activity. On the second day there was a large and spectacular eruption that shook the entire island. I was completely amazed, not expecting anything to happen at all, and so was the MVO. So large explosions can suddenly occur without warning. I wouldn't be surprised if what you are saying comes to pass.

@Hasis I don't get what the bagging of Plimer is about. What he said in the volcano segment on the MP3 file was pretty correct, did you hear any errors? I mean, the way the AGW is attacking Plimer, it looks exactly the same way the creationists. Same techniques, same nit picking. Personal attacks. It's supposed to be science not calling people names. I have a lot of respect for Professor Plimer, he used to be head of Melbourne University Geology and his previous book "A Short History of Planet Earth" was also very good, but didn't get attacked or name called.

CO2 does not unequivocally cause warming. It is not an exponential gas in the atmosphere, only the first 20-50ppm cause the most warming, if you keep increasing it, you do not get increased warming. The system is much more complex then one variable, land clearing and temperature measuring in urbanising centres and reduction of sampling stations produces more warming. Until the Roman Warming, the Medieval Warming, the Little Ice Age can be explained properly (and this is just in the last 2000 years, a blink of the eye) there is nothing really different about the 20th century, we are just coming out of the Little Lce Age. Solar variables over longer climatic times also play a part, as well as volcanic factors SO2.

AGW is basically alike to the last global Pseudoscience consensus which also could be not be critized in any form - Eugenics, which was let by Charles Darwin's son, started by USA and finished in WW2.

You cannot have a unequivocal answer in science with a concensus, that is religion.

By Scarlet Pumpernickel (not verified) on 21 Apr 2010 #permalink


Fine, you are completely entitled to your own opinions. I am now going to shut up in order that we can return to concentrating on this site's specialty.

Best wishes

@Jón..I buy that :-) What i reacted mostly on is that the wind has not increased that much during the last 2 hours but in the last 30 min the chart has increased quite a bit. A noticable change quite abrubtly around 11.30.

So if you would take away the windfactor you would still have quite a big increase in activity around this time am i right?

SP, "if you check Plimer's references you see that he is lying about data" is not a personal attack, it is a simple statement of fact, which can be easily backed up with evidence. Are we supposed to refrain from any criticism of such activities? Why? How does that help anything?

By Luna_the_cat (not verified) on 21 Apr 2010 #permalink

Maybe in Jón's site we need a constantly updated (every 5 minutes like the helicorders?) time-series chart for wind readings instead of only instant readings? So that we can relate bursts of activity with it? If the raw data is available such chart shouldn't require much time to make.

Oh, and as a side note, the GOLA-REYK gps ground deformation chart has been updated:

Although there definitely is deflation ongoing the last data point reported inflation compared to its preceding one. Of course, as always just one point isn't enough to tell the whole story but it looks like the volcano is not going to deflate too much quickly.

Oddly enough, the THEY-REYK chart has not been updated yet, and now it's lagging several days compared to the other one. Is the station malfunctioning? Or are there non-technical reasons behind this lack of updates?

Bill G #299 (if you're still around):

"There was a crack that opened on the glacier on the poro cam from around 1/3 of the way up, down the LH side to the base moments before this activity. Is it possible that the magma has mad its way into the glacier which is feeding this activity? Te front of the glacier looks quite unstable."

In layman's terms:

What you see between the two big cracks on the Ãórólfsfell cam is GÃgjökull Glacier tongue, or what is left of it.

The melt water from the existing vents apparently formed a tunnel through this glacial tongue and 2 or 3 days ago the "roof" collapsed. So this is the end of GÃgjökull as we know it. It's just a shadow of its former self.

More cracks have appeared in the general vicinity of the exit point we're looking at because more meltwater is forcing its way through the glacial ice. No new vents have appeared.

#341 Anna. Having been looking back over the last days shots that all seems very reasonable. With the amount of lubrication there must be under the glacier now I would be very loathe to stand any where near beneath it!
As an aside are people aware that if you go to the Vodafone pictures and choose to go full screen with the button on the left that you get a screen where by clicking and dragging left and right you get your own animation for the day?
This makes it very easy to see the flow that occurred earlier from the opening at lower left on the glacier and the changes it has made to that opening.

@Mr. Moho, THEY GPS station might be broken due to ash fall in the area over the past few days.

There is now a minor flood coming down GÃgujökull at the moment. No danger. It is interesting to see that the flood have started again after a short break few days ago.

According to news reports there is no activity in two of the four craters that did open when the eruption begin. The biggest crater is still erupting, as is one of the smaller ones. But is a interesting question if we are going to see new crater opens in the next few days or weeks.

was just gonna post about that Steve.B can someone please explain to me why that would happen..

Alot of EQ activity in the North fracture zone.

@ SteveB

These flow sequences are fantastic; I'm collating them as best I can for the Newcastle team who are currently on the boat with their laser scanner. They did a prelim channel survey in early March, these images will be great for them.

looks like that glacier, or what is left of it is coming down... do we think that there is some newly hot rock under there, or is this just ineviatable from whats going on at the summit crater?

By paul wakefield (not verified) on 21 Apr 2010 #permalink

@Anna. Anna thanks for the explaination. It may have just been a timing issue as at the same time I was watching this "crack" appear over a very short period of time the new activity started. Was just wondering if the two events were related and which may have caused the other if they were related.

SteveB: Nifty little gush of water!

The flood coming off the glacier is getting pretty large. Is this something new or is this melt water from a few days ago when the plume was taller/larger.

Ahhh, so the outlet glacier did calve as expected. Perhaps this explains the sharp transient in vertical tremor late yesterday.

Good job, Bill G! (#293). Sharp eyes, sir.

EQ action to the north again.

@Mr. Moho, the earthquakes are happening where the magma is being fed to the current active craters. This might signal a change in the eruption, or it might mean nothing at all. We just have to wait and see.

>Odd location. Is it related to the current melt water?

Indirectly, yes.

Could be interpreted as an indicator of magma looking for release elsewhere, as the action at the crater dies down.

The geologists got their 'hot clue' as to where, yesterday, thanks to NASA. Look very very carefully at the shape of the Fimm hotspot.

If you want to understand what's afoot, you will need to go back to the innocuous post from yesterday asking if we had seen an article. There is a link to a summary 2010 paper on Eyjaf and Katla (public access pdf).

Download it, read it. All of it, for once. It's quite comprehensible and it explains exactly what is going on.

The geologists know very well what is happening - they're really very clever, thorough and very, very careful.

Cumulative data analyzed in the paper of recent seismic and movement activity at both volcanoes and the comparative interferometer images posted weeks ago here provide evidence of significant inflation over a wide area to the north, at Godabunga.

That's your major magma feeder point. Told you that it was aptly named.

Regarding the quakes, again no expert opinion...but the chart to look at is here.

The bottom one shows there have been no deep quakes since the 14th. Implying that all the real activity is now happening high up.

Again lay opinion but I suppose that means no new stuff is coming up, so really what is being watched now are almost surface interactions.

I would also guess that means unless you start seeing deep quakes, then for now at least this volcano will just put on a nice pretty show as ice and degassed lava mix.

Another guess would be that the real issue now is going to be what is happening > 10km down and how the lost mass changes things.

Could be completely wrong though.

@Anna Thank you for the link Since you speak Icelandic please stick around you are most welcome

Kver (#354)

Scientists are saying that in all likelihood there was an ice blockage somewhere, that the melt water had been pooling up subglacially for a while.

can you narrow down the search for that pdf file from ysterday I'd really like to read it Thank-you

@passerby (#354) Has there been calving? I have been watching out for it and not seen anything as yet. Do you know if it was captured by the webcams? I'd love to see it.

Firstly thank you for this amazing blog. I stumbled across this Saturday and haven't been able to leave it since.

Unfortunatley the closest I've been to a volcano is the lamporite pipe at Argyle Diamonds which has been extinct for a touch over 1 billion years so not quite comparatable to this..

Just trying to understand what is currently occurring. I'm guessing the magma is interacting with the glacier with the resulting reaction taking the path of least resistance back up through the mouth of the volcano.

My question, if this assumption is correct, is what happens when the reduced glacier becomes the path of least resistance? I'm guessing its easier to eject something horizontally rather than vertically?

@Frito Lay (#296, 309) - firstly, you could have addressed myself personally without the polemic "self-proclaimed expert" bit. Which, I fear, is far from reality because a part of the job we (not only I) do is based on working on active volcanoes since quite some time (in my case, more than 20 years). You have no idea how many times I had to change my ideas because that's what work on an active and frequently erupting volcano forces you to do. You start with a nice set of ideas and then one after the other they're shattered, because reality is a million times more complicated than what you'd have imagined in your wildest dreams. You build new ideas and new hypotheses but eventually you learn that nature is always one step ahead.

I wonder where in my comments here you've ever seen anything resembling me wanting to stop people from saying things. What I did, and for this I take full responsability, is that sometimes I disagreed or proposed alternative possibilities to a statement because, again, you have no idea how many alternative possibilities there are. I have furthermore always said that although I sometimes believed things to be less likely, they were still a possibility. So don't turn the words round in my mouth but rather try to read between the lines (though I believe I've always been clear), rather than getting obsessed with the notion of someone being "established" by a job in a public administration becoming less open and less spontaneous in her or his ideas. While many structures such as our institute (or the IMO and Nordvulk) can sometimes appear a bit static in the way the reveal their findings about an event like this eruption here, most individuals inside are much less so.

Apart from that I am apparently the single one person here on this blog who speaks from the "inside of the machine", so to say, that is, except for Erik Klemetti who is also working as a professional in volcanology. When you're a passonate layman you see things in a certain perspective and you have an enormous freedom to say whatever springs in your mind. That's very fine and it's one of those things that make science advance - provocation, stimulation, discussion, disagreement ... so I feel for people like myself and also Jón who try to make sense of all sorts of data and information during this eruption, it's a gigantic learning experience.

But it's also a gigantic responsability from the moment on that you're expressing yourself on a forum as visible as this blog. I guess no one except Erik really knows how many visitors there are to this site but I guess they're multiple times the number of comments posted here. The news media are certainly among these visitors, as are administrators of all sorts, including people who are in the air traffic security sector and all the like. So every statement that you give here will be sucked up and used for whatever purpose, especially if the "official" volcanologists are a bit slow in posting new information, which is always the case for reasons already outlined in an earlier post. If you find the time and interest to dive a bit deeper into that subject, there is a good read here that is about how two different volcanic eruptions in the Caribbean in the 1970s were handled by the volcanologists, it's about how to deal with the news media and the public, and it's become a milestone in volcanology.

By the way, I've seen that Jón has always been up to the game and never reacted in an offended manner, which I highly appreciate because I have sometimes really given him hell. Oten enough he weathered through it and things happened so tremendously on schedule as he envisaged them that I wished we had him here on Etna. Sometimes I felt there were really other ways to interpret things. And that's where I put the Etna experience in - which is a tremendous treasure of experience, not my own personal but of all who work on this volcano, and that makes approximately 120 individuals in the INGV in Catania.


I think most people fail to understand the concept of "professional discretion" when it comes to the internet. Individuals who are, professionally, responsible in a certain area tend to have a higher degree of accountability and, therefore, less leeway for speculation in high-visibility situations. I know I've encountered times when I've been hesitant to discuss an issue in my profession - software and systems support - because there could be a large number of people impacted; one tends to be more cautious in such situations, and to be frank, I'm not making decisions or statements that could affect billions of dollars or thousands of lives. Those of you who are have a burden far in excess of mine.

I'm perfectly certain that the majority of people reading this blog (participating or otherwise) appreciate the efforts and the candid nature of the discussion between you, Jón, Passerby, and the rest of the professional establishment that have chosen to camp out here. Debates - even contentious ones - are going to occur, and some discretion is going to be required, but any information or propositions shared is just that much more for the rest of us to learn.

That is, in my mind, the whole purpose of places like ScienceBlogs - not only to encourange exchanges between experts (even in diverse fields), but to bring the laymen into the conversation in whatever kind of roll, even a passive one.

Again, thanks to all of you, including Dr. K for providing a place where this discussion can happen.

@Boris: What you describe is not only true for your field, its true whenever you do science. Start with an idea, measure or observe something and the go back to your theory and learn how complicated nature is. And sometimes how simple things are. Very well described.

We are lucky to enjoy such a good weather on Mila web cams.

On Katla web cam it snows. Hmmm.. horizontally.

Good morning. Erik's started a new thread.

Just as a start I have to thank for this amazing blog. I've been following it now for the last two weeks and have learned so much. Thanks!
As great as it has been, being able to watch the eruption out of the window, it gives it extra boost to learn a little about what's realy going on. :)

I wish Jon would use math transform plots rather than raw data from his geophones. Someone posted links to the software necessary; I bet we could get Socuel to implement the transform-data graphing in near-real time.

I mispoke earlier on calving, because I had a false impression of glacier cracking from the Ãórólfsfelli webcam due to plume and ash shadowing; there has been further deterioration but no actual evidence of major outlet glacier failure yet. Still waiting for the sun to shift to see the top of the outlet tongue.

Maybe of we're lucky we'll get an aerial photo posted on the net for a closeup inspection.

@Boris #280, I believe you are getting the message out very well whether or not you think you are. I have appreciated everything you have contributed here and you have the voice of reason and I appeciate the fact that you have an education that I envy a bit. :-) I spent 16ys in college! I never did get to what I really wanted to do and now I wish someone had steered me into geology/volcanology because, after all, I am a rock hound and have been since I was old enough to pick them up. I can study it now and I am in the process of doing so, though I don't have the engergy anymore to go to classes. :-( Oh well, there are people like you and Erik who are patient enough to answer our questions. I learn here all the time.

If Etna erupts, it will be just fine for you to post once in a while what is going on as we know you will be extremely busy! And we will probably turn our attention to Italy. :-)

Thank you, Boris for your input and continued support of this blog.

here is a sample of ATC recording of a Thomas Cook airplane having issues with the ash. The recording is simply done by chance and wonder if there have been more incidents.

Credits to Sunburn on Live ATC for this great recording.

By Eric Roche (not verified) on 21 Apr 2010 #permalink

Boris, you and anyone else can see the tally from the site visit counter, graphics and stats info from link at the bottom of the blog:…

Jon, as best I can recall, is an volcano-enthusiast and volunteer running geophones for a amateur group monitoring seismic activity. It's lovely that he shares his data with us, as we usually get a heads-up of change in activity that we can easily verify on the official tremor detection network graph page for Eyjaf-Katla, and compare them against other data feeds (meltwater flows, EQ events and webcam images) to see if we can make sense of what is happening.

I've been wondering if INGV is collaborating with the Institute in technical evaluation of this eruption, as both groups are responsible for monitoring and analyzing geological hazards for the two most active areas in Europe.

Both Iceland and Italy must contend with numerous high-risk volcanoes that can play havoc with human activity and the environment for months (or sometimes years) after major eruptive periods.

@Passerby (#376) - yes, scientists of the INGV are collaborating with the Icelandic scientists, foremost in the gas emission sector. A group of colleagues from Catania and Pisa went to see the first (Hawaiian-style) episode of the eruption in late March-early April to see the second fissure open. Their report was published at the time on the Nordvulk web site. In the light of the more recent events I guess further collaboration would be useful (also because at Etna there is a lot of experience with long-lasting ash falls and disruptions of air traffic) and certainly appreciated by whoever gets the chance to travel. Problem is that currently funding is down to nearly zero, but maybe the big air traffic chaos of the past few days will help some money to come our direction.

Tangentially perhaps interesting--this link is not a direct comment on this particular eruption:

"... Tuffen expects an increase in explosive eruptions at glaciated volcanoes that experience significant ice thinning, and increased frequency of lateral collapse at glaciated strato-volcanoes in response to anthropogenic warming....

Deeming and co-workers present the results of a cosmic-ray exposure dating campaign at Mount Etna (Sicily), which constrains the timing and nature of collapse of the Valle del Bove, a major volcanic landslide scar on the eastern flank of the volcano. The authors link pluvial conditions during the early Holocene to the formation of a high-energy surface drainage system and to its truncation by a catastrophic lateral collapse event, ca7.5âkaâBP, which opened the Valle del Bove. A possible mechanism is proposed, whereby magma emplacement into a water-saturated edifice caused the thermal pressurization of pore water, leading to a reduction in sliding resistance and subsequent large-scale slope failure. Deeming et al. present the mechanism as one possible driver of future lateral collapse at ice-capped volcanoes and at those located in regions predicted to experience enhanced precipitation.

Concluding the volcanoes and climate change theme, Tuffen and Betts draw together the thoughts of delegates at a second colloquium discussion session, which focused on Volcanism and climate: chicken and egg (or vice versaâ)? ...."

Hat tip to

@Boris Behncke

"all who work on this volcano, and that makes approximately 120 individuals in the INGV in Catania ...Problem is that currently funding is down to nearly zero, but maybe the big air traffic chaos of the past few days will help some money to come our direction."

There might be climate change scientists lurking about. Better to speak quietly.

That's what I though - there is potential professional overlap in interest in gas and ash emission and ultra-fine ash aerosol dispersal modeling.

Your main selling point? A long history of frequent activity at Italian/Sicilian volcanoes suggest that there is very high risk of further eruptions in Europe (both Iceland and Italy) that would be exceptionally disruptive from 'add-on' eruptive effects.

In other words, Europe faces a high probability of stratovolcano eruptions from Etna (and others) that will contribute to and worsen ash density and aerial extent of volcanic ash impact to air traffic - especially if atypical air mass movements continue sporadically for the next 12-36 months.

You can't get any more 'odd' than seeing the present ash plume progress in westward backflow movement - dead against the normally prevalent west-to-east winds of the north Atlantic.

Makes for a good sales pitch for seeking 'emergency' funding support from the EU, with the explicit aim of supplying expert professional insight and advice to European meteorology and air traffic control authorities.

Consider partnering with NASA and ESA agencies for specialty sensor satellite imaging support. Washington has a vested interest in providing agency technical assistance where projected losses from air travel shutdown over the Atlantic to Europe will adversely impact the fragile state of economic recovery in the US.

Climate change science makes for interesting opportunities.

"Were the Dark Ages Triggered by Volcano-Related Climate Changes in the 6th Century?
(If so, was Krakatau volcano the culprit?)

by Ken Wohletz
Los Alamos National Laboratory

... In order to test this Proto-Krakatau caldera hypothesis, I arranged through the UK Channel 4 to fund an expedition in 1999 to the Sunda Straits. I asked Haraldur Sigurdsson and Steven Carey to undertake this effort because of their familiarity with the region."

How about going to the new thread? Is anyone having as hard a time catching up as I do? LOL

Nice link, Raving. Thanks.

@280, Boris, your message is absolutely getting through. My students and I thank you and Erik for the clarity and depth of your posts which have enlived both our lessons and comprehension no end since I discovered this site.