Eyjafjallajökull update for 5/3/2010: Flights banned anew over Ireland


The steam plume from a lava flow moving down the slopes of Eyjafjallajökull on May 2, 2010.

A quick note on the activity at Eyjafjallajökull in Iceland: The ash from the ongoing eruption has caused a partial closure of airspace over Ireland from 0600 to 1200 on Tuesday May 4. This is one of the first closures of European airspace since airspace reopened over 10 days ago. This closure is based on the predicted location of ash in flight corridors over Ireland tomorrow.

The Icelandic Met Office has released two interesting updates on the activity at Eyjafjallajökull. The first describes the current state of the eruption:

The eruption is mixed, with the lava-producing phase being larger than the explosive phase. During the last 2-3 days, the plume has been darker and wider than in the preceding week. Tephra fall-out in the vicinity of Eyjafjallajökull has increased. Dark grey ash clouds are observed over the eruptive site. White steam plumes are rising from GÃgjökull, north of the eruption site. The elevation is 4-5.4 km (13-18,000 ft). Clouds of ash at lower elevations were observed drifting south-east of the eruption site. Moderate ash-fall was reported in the village of VÃk at noon, Sunday, located 40 km south-east of Eyjafjallajökull.

From the location of the steam plume over GÃgjökull, lava has advanced over 3 km north of the eruption. Steam plumes over the glacier edge from 19:40 GMT suggest that lava may have advanced even further. A rough order-of-magnitude estimate of lava volume can be obtained from the dimensions of the ice canyon. This estimate gives a lava production rate of-the-order 20 m3 s-1 (i.e. 50 tonnes s-1). The explosive phase may be 10-20 tonnes s-1.

This update suggests that there is more ash being produced and mentions the lava flows on the flanks of the volcano (see image above). The second update came later today:

Largest eruption plumes were observed at 5-5,5 km height (17-18,000 ft) estimated from the Icelandic Coast Guard (ICG) flight at 14:30. The plume rises higher after large explosions. It is heading east-south-east to south-east from the eruption site.

This indicates why the new ash closures could be predicted as the ash column appears to be taller than in the last week or so. This comes along with the increased meltwater coming from the volcano, noted by a number of Eruptions readers watching the webcams. You can also see a great collection of photos of the effects of the eruption from around Iceland.

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Around 21:00 UTC there where more deep earthquakes. The deepest of them where at 18 km depth. This earthquake activity can mean two things.

1: There is more magma coming up and is fracturing more rock as it pushes upwards.
2: There is a collapse going on at that depth due to magma drain because of the eruption.

Hi Jón. of those two I'd favor the first for the simple reason that the crust is meant to be more ductile than brittle at that depth (i.e. it will only "snap" (= earthquake) when there is enough tension). .. assuming again that the crust is only 20 to 25 km thick here.. to put it another way, I'd kind of expect a gentle ductile sag if the crust was responding to evacuation of magma, and, if such removal of magma resulted in seismic activity, then I would guess the activity to be more dispersed over time and depth and not appear in such a short sharp burst at a fairly focused depth as we are seeing here.

Guess I am not making myself very clear... ok, last try: I think we are seeing another one of Peter's boluses. The earthquake activity is nowhere near as intense as the EQ series we saw at the beginning of the eruption because the channels to the surface are now open and functioning so there is not the same build up of pressure and consequent fracturing of country rock. ... my 2c anyway.

If this reasoning is correct, I'd dearly love to hear of any theories as to how or why melt from the mantle/crust boundary would be released in such pulses and not as a steady stream.

By bruce stout (not verified) on 03 May 2010 #permalink

Well does the "pattern" of the EQ´s have any meaning? Looking at the map it seems to have a north/south stretch. Would this indicate a narrow chamber or an intrusion north/south?

The Hvol cam is really wierd!

I would say all three cams are wierd..:S

The way they are lined up must have some meaning. And the tremor amplitude graphs have been dropping dramatically in the last 5 hours or so.

.. further to my comments on the other thread. This N/S alignment intrigues me neverthess. The second fissure at Fimmvorduhalsi was also N/S, although that was probably just a superficial expression.

It looks to me like the intrusion is following a N/S break on the domino blocks making up the fracture zone (basic model: the northern and southern boundaries of the zone trend E/W and in between are a number of blocks that break N/S). Passerby would be the one to ask on this. Quite fascinating when you think the basic alignment of Eyjaf is E/W.

By bruce stout (not verified) on 03 May 2010 #permalink

re. #9 If you squint you can just see some incandescence on the lower of the two glowing areas.

By beedragon Canada (not verified) on 03 May 2010 #permalink

Those waves of earthquakes deep under
a volcano doing a chunder...
The feeling I've got
is that to ignore the lot
could be a momentous blunder.

By Reynir Heiðbe… (not verified) on 03 May 2010 #permalink

Well, that was fleeting. Daylight disappeared in a flash.

By beedragon Canada (not verified) on 03 May 2010 #permalink

Looks like is EQ day today:
5.2 19.3 SULAWESI, INDONESIA
6.4 20.6 OFFSHORE BIO-BIO, CHILE
5.5 10.7 SOUTH OF ALASKA
6.1 82.3 IZU ISLANDS, JAPAN REGION
plus Eyjas 12 quakes...

By Renato I Silveira (not verified) on 03 May 2010 #permalink

The three most recent deep quakes bracket the original 7 deep ones quite well. No definite trend that I can see... other than the NE/SW orientation that was mentioned earlier.

There once was a volcano from Iceland
She said "I'm erupting and isn't it grand!"
She spewed lava and ash,
Costing airlines tons of cash,
But said "I don't care. Talk to the hand!"

By beedragon Canada (not verified) on 03 May 2010 #permalink

EJ you stand so tall and proud
Please uncover yourself from that shroud
Your audience is here
Your performance so near
Yet we can't see a damn thing for cloud

A theory I have about the north south orientation of the recent Ejay quakes is that this is the "rifting" of the mid Atlantic ridge. This area is a weak spot...why I am not sure.
This could open a conduit to more Basalt to erupt. Lets hope the gas content is low and does not erupt violently enough to effect air travel or even possibly a way way way out side chance effect the climate due to SO2 release vis a vis Laki.

Like I said way way out side chance of that at this time but I like to speculate.

By Dasnowskier (not verified) on 03 May 2010 #permalink

If the ash makes it to where I am now (Edinburgh), I'm probably the only one who's actually going to be 'happy' about it. I don't mind staying here for a little bit longer, as I'm looking out of the window and seeing Calton Hill and Arthur's Seat in the 'backyard' ^_^ .

I've been checking out the roofs of cars around here and a lot of them have a very thin layer of dust on them. I don't have a microscope here, but maybe some of the other blog readers (maybe even living in Britain) can tell me if there's a high likelihood of it being ash from Eyjafjallajökull.

13th EQ and this is the deepest one too.

Isn't it unusually grey and bright on the Hvolsvelli cam and dead dark on the Thorolfsfell cam? But then it is night time there so hard to say what's up...

Today's IMO-IES report states that deflation continues. I think that would support subsidence as the cause of the earthquakes.

FYI, the most up-to-date publicly available graphs are a day old, and the semi-continuous stations haven't been updated since the 28th.

@8. Rifting occurs perpendicular to the principle stress directions (tension or stretching). What this means is that the horizontal orientation of the fault will the run perpendicular to the direction of stress. For example if there is tension oriented along an East-West direction, a fault will form that is oriented N-S. That's very simplified, where we have a rift you have several parallel faults called normal faults that allow the crust to pull apart..and also allow any magma present to reach the surface.

The Wikipedia page is not too bad:
en.wikipedia.org/wiki/Fault_%28geology%29

I know there are some USGS pages on faults as well.

The tension could be regional stresses (tectonic) or local and close to the surface due to magma deforming the crust as it tries to break through. The former would produce bigger faults both horizontally and vertically. It is along such pre-existing fractures that the magma probably travels along within the crust.

@PeakVT [24]

I could easily accept that if they were around 0 to 7 km deep... but these are directly under the summit and west of the ones associated with the fissure then the caldera eruption. You could even see the "pipe" open up from the main group at about 3 to 4 km down that lead over to the caldera.

No, these are deep... and out of place. I could see it if a massive amount of weight has been lifted (ice) and things are re-adjusting... sort of an uplift at low depths as the upper levels settle in. That might work.

But hey, I'm just a spectator. Been wrong before.

Jon is right those quakes are a sure sign something is happening...what that is still remains to be seen....If the quakes keep up at this rate....I will bet an e-beer we get a new vent opening up soon.

I was referring to the GPS graphs at IES in my previous post.

@Izzy - I think it's just foggy, and the lights near the Hvolsvelli cam are making the mist glow.

14th EQ largest at 2.0 about 10km deep

@PeakVT, The only problem with that is the fact only the North-South has dropped down since the eruption started. But not East-West, so there is still plenty of magma down there left to start erupting.

What would be the effects of a caldera collapse at Eyjafjallajokull? If a collapse did occur, 1. Would Katla be set off? and 2. How would it affect the eruption at Eyjafjallajokull? Also, what is the chance that one would occur soon (within a couple of years)? Just curious because of the recent deep earthquakes and deflation.

I did record the ML2.0 earthquake, it was tectonic in nature. Not created by magma movement directly it seems (I might be wrong however). So I have no idea what is going on at the moment.

The ESK tremor plot is on the up swing

StarBP EKoh, Erik or Boris can tell you for sure but there is going to have to be a whole lot more lava come out and a lot more vents open before there is a chance of that happening....The effects would depend on how big the caldera was before it collapsed.

I would lean more toward a Laki type of event before a caldera collapse....but really I don't think either of those things will happen here. We may see another vent or two open up though before it's finished.

@PeakVT, good to know it's only fog...was worried the ash would engulf the cams

ESK plot still rising and Jon's helicorder is getting more interesting too

@Randall Nix, The press in Iceland is at sleep now. No news on what is going on in Eyjafjallajökull. But the earthquakes are at great depth, so whatever is going on under the volcano might not manifest it self for some time now on the surface.

Does anyone know the weather report? I don't need a link, just a brief on what it is.

Thanks.

By Diane N CA (not verified) on 03 May 2010 #permalink

Sally Mamiesdottir, possibly.

@Eddie - thanks for link but for us that are outside UK it's inaccessible

By Helen Leggatt (not verified) on 03 May 2010 #permalink

On Ãórólfsfelli all I can see in full screen mode are pixels. Many orange reddish colored pixels where there was yesterday the glow of the plume over the lava flow. Is that twilight or just my imagination?

By Renato I Silveira (not verified) on 03 May 2010 #permalink

@Renato All I see is a bluish screen. Pretty much the same on the Hvolsvelli cam, except it has lights. Couple of the Mulakot cams show fog.

There just where few earthquakes at ~1km depth now in Eyjafjallajökull. The largest one was ML2.9 in size according to the automatic results. This might not be a good sign. But we just have to wait and see what is going on for the time being.

The earthquake activity has picked up a lot even as the harmonic tremors seem to have dropped off. Not sure what it all means but there is an interesting N-S line that the tremors are occurring along.

Perhaps the activity is heading to long dormant Tindfjallajökul or perhaps this is coincidence. In any event the majority of action is under Eyjafjallajökull so this is where we should be looking for new activity. Time will tell, but it seems something is brewing.

Hans yeah something is brewing for sure....just what is the question;)

Jon still noting on the news? Those depths are getting a lot shallower.

Winds should be from the general direction of Iceland to |Europe for at least two weeks and even longer. This weather pattern tends to stick at this time of year. Keeps things pretty cold too. This should prove interesting for airlines, if the volcano intensifies.

By Jonathan Witty (not verified) on 03 May 2010 #permalink

Jón, it's foggy, it's shaky, it begins to make me scarry. I must go to bed, but I don't think I'll be able to get any sleep. This volcano is addictive. I envy you for being so close to all the action, but, on the other hand, I'm glad I'm so far away and hoping that this will end in another beautiful performance of fireworks, and that's it. Get yourself safe!

By Renato I Silveira (not verified) on 03 May 2010 #permalink

I saw this film when I was a child - Krakatoa, East of Java (never understood why "east"). I remember that, shortly before the "Big Bang", it was foggy, exactly like it looks now on Mila's cams. That's what scares me most. The memories of the fog and the fact we can't see what's going on, and knowing something is going on.

By Renato I Silveira (not verified) on 03 May 2010 #permalink

Where would I be able to find a list of EQ that are older than 48 hours? Sorry if this is a childish question...

#61 Read all the links on the following site and use the search the site in upper right hand `corner' for your topic of interest on earthquakes.

http://en.vedur.is/earthquakes-and-volcanism/earthquakes/

Go back and read all of Erik's previous blogs and individual's postings for their take on earthquakes and links posted by individuals.

Some great articles have been posted in previous blogs.

One said that the orginal eruption - the earthquake swams were 70 plus! Also gave a video site to see what the earthquake swams looked like as a timelapse.

Thank you JB i found that had the time lapse. There is a dormant volcanoe Tindjallajokull that seems to be of interest especially after that video...

Thank you also Renato. Would you like the link for the time lapse of EQ? Its really very good.

@Renee
Thank you for the link. I'm trying to get there but connection is bad. Do you think something is about to happen?

By Renato I Silveira (not verified) on 03 May 2010 #permalink

@Renee, try the Katla cam. I think we can see the plume (or just more clouds), at least, something.
http://www.ruv.is/katla/

By Renato I Silveira (not verified) on 03 May 2010 #permalink

The recent EQ in the 48 hours seem to be moving towards Tindjallajokull. On the time lapse the same thing seemed to have happened starting in March before this eruption began. It may be a pattern?

@renee [61]

"Where would I be able to find a list of EQ that are older than 48 hours?"

Well, if you can get it to work for you,

hraun.vedur.is/ja/google/index.html

But fair warning, I couldn't get them to render in Google Earth. I had to go in and un pack the KMZ, fiddle around with the KML inside of it until I could fake Excel into treating it as an XML file. The I had to wrestle them more to get the usable Lat/Log/Date/Depth out of them. Pain the hooey but I got it. One laborious year at a time.

Ideally, you should be able to just click and view it in Google Earth. That long route was needed since the web interface yields a database error everytime I try to use it. (I have since lost the link to that)

Elsewhere, you can try running this page through Google Translate (or whatever machine web translator you wish):

hraun.vedur.is/ja/viku/sidasta/

It allows you to go back by a week at a time but I'm not sure just how far back you can go.

Best-O-Luck.

Well according to volcano discovery the Tindfjalla volcano has not had an eruption since late pleistocene early holocene. And even then they were small eruptions it seems.

However laying dormant for so long and the fact that it is an explosive stratovolcano a big eruption here would be bad i think.

But i am more inclined to think of the EQ pattern as connected to EF volcano. Some magmatic intrusion to the north and south.

Not sure wether these quakes are tectonic or magmatic though.

Jon thought the 2.0 was tectonic but wasn't sure.

Have you looked at Jons Helicorder lately?

@renee, #61: Try this URL and see if you can find anything there:

http://hraun.vedur.is/ja/viku/2010/vika_17/index.html#mark

As far as I can see EQ's for the last 15 years can be found week by week. Don't know if any lists can be found too. I'm at work now and have limited time with limited priviliges (none!) to install any softwares to check those postscripts links, which looks promising(?).

#71 Daniel
I think it's unlikely they are tectonic, unless some kind of subsidence is occurring at such depths. We have a surprising event here, mixed magma, different kinds of eruptions. Its activity is at full length. I should expect magma intrusion going who knows where to. But these are mere suppositions of someone who loves volcanoes but knows very little about them.

By Renato I Silveira (not verified) on 03 May 2010 #permalink

The last 3 EQ's have been bigger and very shallow.

To all you "newcomers" there are some essential sites for monitoring the development of earthquake activity:

Soceul has perhaps the best collection of sites on the eruption in total (add the http link at the front):
islande2010.mbnet.fr/2010/04/eyjafjallajokul-links-liens-a-propos-de-leyjafjallajokul/

More importantly, you MUST view his animations of seismic activity prior to the eruption to get things in perspective:
http://islande2010.mbnet.fr/2010/03/eyjafjallajokull-levolution-des-der…

@EKoh #25 thanks for that! I was referring to the simplified tectonic structure of the South Iceland Fracture Zone found in Fig3 on page 4 of this document:
http://www.earthice.hi.is/page/ies_geology

Which is kind of scary because the last thing we want is any kind of propagation along one of these domino blocks towards Tindfjalla.

@Daniel 71, Don't be fooled, Tindfjalla has produced huge eruptions in the past including an ignimbrite sheet. We definitely do not want any hot fresh basalt firing up any deeper reservoir of rhyolite under Tindfjalla (if there is one!!).

By bruce stout (not verified) on 03 May 2010 #permalink

Cams are useless and I will go to bed. I know when I turn my back she will behave as a bad girl, but that's the way they play tricks on us. We're in the realm of some kind of big event here, I know that for sure. Enjoy the show. And fare thee well!

By Renato I Silveira (not verified) on 03 May 2010 #permalink

Pardon, an inexcusable laspe on my part: I forgot to mention the source for that last info on Tindfjalla is Heidi Ritter who contributes here. If you ask her nicely she might send you her thesis on Tindfjalla ;-)

By bruce stout (not verified) on 03 May 2010 #permalink

Bruce you are so right... But I am curious to see some recent GPS for that area.

Jon! (#56) Wouldn't an area such as Kerlingarfjöll (SW of Hofsjökull) be something to be more apprehensive about? To judge by the pictures on the first three or four pages of www.google.com/images?q=Kerlingarfj%C3%B6ll&rls=com.microsoft:sv:IE-Add… Kerlingarfjöll sports the following volcanic features:

A largely basaltic and partially glaciated tuya
Cinder cones
Very large rhyolitic effusions
Active hydrothermal areas (hot springs)

Or is the Kerlingarfjöll area considered to be part of the Hofsjökull volcanic complex?

By Henrik, Swe (not verified) on 03 May 2010 #permalink

#75 Renato
I do not think its tectonic either but one can never be sure. All events so far would suggest a magmatic intrusion to the north and south at a very deep level. This would be a cause for concern since noone actually knows for sure what kind of magma reservoirs exists down there.

#77 Bruce
Dont get me wrong. We would definitely not want a second eruption at Tindfjalla. What i was going for was that the intrusion even though it shows some signs of going north/south has "only" produced two events towards tindfjalla. The rest is still centered around EF. I just think that if something is going to happen i believe that EF will be the one putting up a show.

But I do get your point and it will be interesting to see what the next few days will bring.

Lets hope that mother earth is NOT in the mood for a game of domino.

and to make matters worse, I got her last name wrong. (I am not even sure if she wants it public so I'll just go and jump in a cold lake now and come back when this is all forgotten)

By bruce stout (not verified) on 03 May 2010 #permalink

See now, the Eyjafjall is splitting apart, just as we discussed in the last thread. I´m believe it´s a rift underneath this volcano, how could otherwise be so high? I saw the documentary show yesterday and they talked about the Lakà eruption, many kilometers long, and 240 (? if i remember right) volcanos.

By snotra viking (not verified) on 03 May 2010 #permalink

Sorry, Google translator changed Ireland with Portugal! Hope come!

By Renato I Silveira (not verified) on 03 May 2010 #permalink

Vodafone cam is up. Seems like a lot of smoke in the jökull area.

By snotraviking, sweden (not verified) on 03 May 2010 #permalink

I have a feeling she is going to put on one heck of a show...

@ Daniel 82.. sorry, I didn't mean to imply you were wanting a big event under Tindfjalla, just wanted to put you right on its history.

BTW, I just checked: Of the last sequence of quakes the two most northern ones at 63.7° and 63.68° are only 1 km deep, which is kind of good news as this means that there is no deeper propagation towards Tindfjalla so that is a bit of a non-issue at this stage. What they might mean though is that the magma is nearing the surface in the Markarfljot valley.

By bruce stout (not verified) on 03 May 2010 #permalink

Something looks to be very different on the Vodafone cam, to judge by the few glimpses possible trough occasional gaps in the fog. I really wish the clouds and fog would relent!

By Henrik, Swe (not verified) on 03 May 2010 #permalink

small break in the clouds on the Poro cam and Voda phone large steam plume

For a short moment at 7:15 on Vodafone-Webcam one could see huge flooding and right now 7:18 it seems that the steam (lava) already reached the valley now. The whole area above the former lake area seems to be completely different from yesterday! I think big parts of the glacier tongue just vanished...wow!

By Thomas Wipf (not verified) on 03 May 2010 #permalink

@ snotraviking, have a look at that pdf on iceland's geology. It is very informative.

http://www.earthice.hi.is/page/ies_geology

Following up on the idea of a fissure opening up in the Markarfljot valley. That could lead to some very interesting water/magma interactions! (damming, phreatomagmatic explosions, flooding, etc) Let's just hope for the sake of the locals that this doesn't come to pass. Luckily, it looks like activity will remain at the active vent, as one would expect.

By bruce stout (not verified) on 03 May 2010 #permalink

I agree - from current views it's almost as if the glacier has collapsed.. v. different contours visible....

By Helen Leggatt (not verified) on 03 May 2010 #permalink

Here is a link to the IAVCEI RSC web page for the Eyjafjallajökull 2010 eruption. Links to the webcams are posted towards the bottom of this page.
http://sites.google.com/site/iavceirscweb/eruptions/eyja

Tips for using and posting links via Google Translate.
Some of the articles posted on Icelandic websites are written in English, but others require translation. If you want to post a link to a translated article, load the Icelandic link into Google Translate, press the Translate button and then copy the full address of the translated text from the TOP of your browser e.g.

From VISIR: Increased explosive activity (3rd May)
http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layou…

From RUV: More activity now than at the begining (3rd May)
http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layou…

Katla Webcam
http://translate.google.com/translate?hl=en&sl=is&tl=en&u=http%3A%2F%2F…

Thanks to the posters here for the original Icelandic links.

By Philip Mulholland (not verified) on 03 May 2010 #permalink

4 More earth quakes, is it just me or are they getting closer and closer towards Hekla each time?

Helen. Indeed it looks like a completely different view today at http://www.vodafone.is/eldgos/en

I wish the fog would blow away so that we can see the base of the glacier.

Maybe the camera view has just been changed but it actually looks like half the mountain is gone..:o

Heck just looked at the vodafone cam and it looks like a completely different glacier today!

Looking through fog can be very misleading, but it looks as if the area behind the large tuff boulder mainly consisted of glacier and that there now is a huge pit.

@ Snotra Viking (#85). I agree with that! This possibility was originally discussed several weeks ago at the very start of the main eruption or just prior to it.

By Henrik, Swe (not verified) on 03 May 2010 #permalink

#95 Kyle.

I believe they are a way from Hekla.

And if i have read correct in these forums hekla usually erupts with little or no warning. Normally within a few hours after tremors has begun. So until she blows noone knows. :)

Looking at eldgos camera seems that the lava flow has advance quite a good distance tonight. Maybe the lava front reached the glacier piedemont....

By David Calvo (not verified) on 03 May 2010 #permalink

thats a pretty vigorous plume from the main crater. It also looks more ash rich.

By bruce stout (not verified) on 03 May 2010 #permalink

I think one explanation of the different view is: the vodafone cam has a wider angle now. But now on 7:54 we see the whole volcano with a lot of ash eruption. Great scenery!

By Thomas Wipf (not verified) on 03 May 2010 #permalink

@103 the camera is exactly as it always has been.

Has the Ãórólfsfelli cam been moved? Looks to me as if it's almost level with the main crater ... though maybe that's an optical illusion due to the fog in the valley. Another thing: everything seems to be covered in black ash and there seems to be hardly any visible snow/ice left?

I don't think the cam has been moved because the picture is the same on vodafone cam In my opinion I think it has collapsed and if you notice everything seems to be covered in ash. I knew something big would happen when the cams were obscured by fog murphys law I suppose.

Two dark "pillars" now in view at bottom-most viewable area of glacier - rock or ice, not sure - but huge gaping hole between them!

By Helen Leggatt (not verified) on 03 May 2010 #permalink

Dear all, beautiful thread. Been following for a few days now. Jus an idea: in order to better see the differences in the landscape on Vodaphone cam: open a second tab, and rewind it to pick a time from the recent past with clear skies at the exact same hour of the day. That way the tricks of the light do not fool you into believing things have gone or appeared.

Eg: I am comparing the current image with the one on April 27, 14:48 (cam time). This shows many things are still the same, but much ice and snow is gone. Oops, as I say this, fog blocks the cam again..

It got very dark all of a sudden on vodafone cam. Was such nice view just a few minutes ago. Now it pitch black almost.

Indeed: Vodafone is still in the same position. The fog on the ground makes the volcano look smaller and wider. And there is not so much snow anymore but grey ash. Great lesson in natural optical fooling....

By Thomas Wipf (not verified) on 03 May 2010 #permalink

@Daniel: it may be the fog that sweeps up from below from time to time. I see more gray than black..The stones in front of the cam are still clear..

I have been comparing an image from this morning from one taken yesterday and imho there is a big difference the centre has collapsed and on the right it has more of a steep slope now.. Does anyone agree

@Ruby - that's what I am seeing, too, after about 10 days of staring at the glacier! I also think the "tunnel" has collapsed up from the mouth and left a gaping crevice - again, all speculation from observation thus far today :)

By Helen Leggatt (not verified) on 03 May 2010 #permalink

Not sure but I do not think its fog coming up towards the vodafone cam. Left side of screen is alot lighter in colour than right side. Seems more like smoke to me.

Dont know but i think there will be something big in a not so distance future..just a gut feeling.

Daniel! That's Dante's Peak, not Eyjafjallajökull! ;)

By Henrik, Swe (not verified) on 03 May 2010 #permalink

Great view currently on the Vodafone cam...

Watching the heavy dark ash cloud and the wind-direction . I would sell my stocks of airplane-companies today! I think it will hit parts of Europe again!

By Thomas Wipf (not verified) on 03 May 2010 #permalink

#119 It does not look to be nearly high enough. Yet.

By Henrik, Swe (not verified) on 03 May 2010 #permalink

#117: Comparison between 2.5.2010 9:35 and 4.5.2010 9:35 in Voda camera is interesting

#120 Indeed it is. An immense amount of ice has melted in that time.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

You can catch a glimpse sometimes of the ash plume on voda cam. It looks to be alot bigger now than earlier today. Either that or the wind has shifted towards the cam.

This is so frustrating I wish the fog would clear so we can see what she has been upto during the night I think she has been very busy while she has been hidden from view

She must have heard me the fog is breaking up again can now see the plume

I can`t recognize me at all! Have they changed the vodafone camera or is the half of the mountain missing??

Now that is some heavy ash fall. Voda clear..Almost.

Fantastic! So fantastic! Yes, I see now that the wiew is is the same but the mountain is like collapsed. Maybe thats why the eartquakes earlier. So typical that we couldn`t see that! I`ve been watching this mountain sing now for over a week....

Fantastic! Thanks Mr.Moho

@Sofia - the mountain has not collapsed, but the glacier has, especially on the right side. Also, the lack of snow cover and the fog in the valley changes how things look quite a bit.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

The ashfall overnight must have been pretty heavy. You can see the thickness of it coating the glacier in the Vodafone close up.

By bruce stout (not verified) on 04 May 2010 #permalink

#129 Yes that is what I have been saying all along see comment 106 and 112

Hmm, I'm not so sure that the glacier tounge has changed that much. Probably it's just the fallen dark ash on the ice that make it look that way. ;)

#122,121: On Mulakot cam,I can see what looks like light reflecting off a lot of floodwater at the base of the mountains.

By mags,England (not verified) on 04 May 2010 #permalink

@ Mr Moho (128) Good to have a possibility to compare the images. The colours had changed - white to black and black to white on the images, so this could make the differences. The glacier is black of the ash, the foreground that used to be dark is now white of the fog.

It looks like tremors have decreased much over the last hour or so. I wonder if this eruptive event (I consider it as such, given the amount of ash being ejected. It most probably started last night when clouds blocked the view completely) has marked the beginning of the end of volcanic activity. Or if it's the start of a new and more interesting, possibly long lasting, phase.

MÃla has changed the orientation of the Hvolsvelli webcam - it's pointing more upwards now, so there will probably be less washout from the road lamps in the coming nights.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Hi, I'm looking Katlas web cam. I'm not sure but are there somekind of flood or meltwater at opposite side of hill or am I seeing totally wrong? (I really hope so!)

have been specifically following changes in shape of tunnel roof over main crevice for several days, don't see a big difference from yesterday in the brief glimpses available - ashfall was heavy!, certainly changes the look of contours. Per report from last night, en.vedur.is/earthquakes-and-volcanism/articles/nr/1884
as noted earlier, water comes and goes in regular pulses. Depends on when you see the river what you think. We need x-ray vision!

By birdseyeUSA (not verified) on 04 May 2010 #permalink

@Manni - thanks for that - have shared it :) Great video of what we've been watching over last day or so! Good to see the scale and power of it.

By Helen Leggatt (not verified) on 04 May 2010 #permalink

Days of sitting down
Eyes rejoice or strain
Today I stand up?

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Is it just me or has the Mila Valahnuk gone completely bonkers? It just blinks marrily how many seconds ago it went offline.
Could someone go and give it a jolly god horse kick? Or perhap's a Tölt-kick:)
Also, the Thoro-cam seems to be totally rapt up in a never ending stream of either ash or the damnedest fog (vog) I have ever seen. But it seems rather dark so I would guess ash.

Comparing the before and after pictures tells me there has been one mighty burp during the night by the Lady, she who once was so pristine and white in her diapers now seems to need a change bad... ;) I wouldn't want to see that kind of baby-wipe...

Lady of lava
Cloaking the ice
Reveal thyself

By Helen Leggatt (not verified) on 04 May 2010 #permalink

@Carl - she's put on her little black dress for a night out painting the town red ;0)

By Helen Leggatt (not verified) on 04 May 2010 #permalink

Gone brain dead - sorry, haiku-philes - @146 ' eyes rejoicing or straining'

By birdseyeUSA (not verified) on 04 May 2010 #permalink

http://www.ruv.is/katla/

Can anyone check this out. I'm still wonderig is there happenig something! Just look the(left) hill and there is lot of water or mud coming down...Is that normal? I Think not.

Just now there was a clear spot in Voda cam. Views of the front of the ex-glacier a plenty. I think I saw some collapses in the right side, near Santa's face.

Watching at Katla webcam, quite a lot of clouds in the background...

anyone know at what direction is pointed Katla cam?

@151 Timo I've looked at full screen and it is difficult to figure out what that is. Maybe if the sun comes on some more there will be better lighting and contrast. I can't tell at this time.

Joking, Chris :-P But looks like the glacier is only façade as of now. Looks gutted.

Also there are greyish-coloured vapors ascending from the canyon between the black plume of the vent and the white plume of steam. Lava-emitted fumes?

Vodafone's lower picture shows that the round tube that the meltwater exits from took a bit of a beating over night. It looks like it's starting to collapse under the weight.

By beedragon Canada (not verified) on 04 May 2010 #permalink

Yes, it looks like there has not been that much of a change except for probably a lot of collapse of the glacier where the lava is flowing, and the covering by ash of the snow on the near side of the mountain. It is not clear whether the ash came from explosive lava-ice-water interaction or directly from the vent area within the summit caldera; it looks like some snow is remaining without ash near the summit (at right).
It looks like of the glacier only its frontal lobe is remaining, and higher up the valley it has been largely consumed by the lava flow.
The eruption appears pretty vigorous but I do not see much reason to suspect something tremendous is going to happen soon as some suggest; tremor levels have actually diminished since the very strong activity a couple of days ago.
If weather conditions remain as they are in this moment (pretty clear view), that should be spectacular to see at night !!!

@160 probably seeing ash fall?

By birdseyeUSA (not verified) on 04 May 2010 #permalink

From the Thorolsfelli webcam to me it looks like the steam plume is increasing in volume. Is it only my impression?

#162 Boris.

Maybe you have already answered this earlier (couldnt see it) but the EQ´s a while back. All at around 14-20km depth, same magnitude and stretching in a North / South direction. What could that mean?

I mean most EQ´s have occured at a quite shallow depth, around 1 or 2km but these were different. Could it be the feeding magmachamber or a separate one?

Rrrrr- vodacams go out for me as soon as the viewing gets good - but on Thoro zoomed in can see what you mean about maybe lava-related smoke/vapor/whatever you would call it.

By birdseyeUSA (not verified) on 04 May 2010 #permalink

#163 No, ash falls and is brownish. Perhaps those "fumes" are steam not as dense as the cloud in the back of the glacier tongue.

I wonder if those are 4x4s seen just above the floodwaters to the right (downstream) side of the gap in the moraine - that would confirm my suspicion that people are now driving up to the glacier along the line of the old, washed out, 4x4 track ...

@Daniel (#165) - those earthquakes are difficult to interpret; they could be related to magma recharge at depth, or some settling of the deeper portions of the feeder system. In many cases, volcanic feeder systems are elongate, especially in an area of tectonic rifting, but in reality it is difficult to say, because from the available data do not give the focal mechanisms of the earthquakes (that is, the type and orientation of rupture that produced the earthquakes) and so very little can be said.

From my views of the eruption via the webcams there is only black ash rising from the active vents, and white vapor from the lava interacting with the pathetic remains of that poor glacier. Everything else is weather cloud, which today is quite low.

I'm going to go out on a limb and predict that the ice arch at the outflow is going to collapse in the next hour. I believe I have seen parts falling from its underside.

Just an observation but would what were seeing here tell us that the last eruption was not as bad as this one. The glacier would have taken a long time to get to the size it was pre-eruption. Surely the glacier would have been badly scarred if the last eruption did similar damage. I don't think 100 years of ice build up would have hidded those scars.
Any thoughts,

Just to the right of the glacier tongue, and at about the same level as the top of the melwater chute, is an almost perfect black circle that looks like a big button. Is this the end of a lava tube?

By beedragon Canada (not verified) on 04 May 2010 #permalink

@168 That's probably where the TV news footage was filmed in Manni's #144 message.

@Chris, #169 - well since you are in Reykjavik I assume you know my countrymen - these could be scientists, newshounds, the hangers-on to those groups, anyone who could invent an excuse - or simply people who snuck past the police when they weren't looking :-)

@Kaboom The ice flows from the top to the bottom of the mountain in something like 50 years or so - when I was on Gigjokull at the start of the decade you could still pull bits of plane wreckage out of the ice on the snout of the glacier (which was a lot larger than it is now). The plane crashed on the top of the mountain soon after the war I think. With fairly rapid accumulation, as the mountain is 1600m high and the ice equilibrium line is 1100m or so, the glacier could regrow in a century or so. The glacier would quickly hide any lava flows.
Additionally, there was evidence for jokulhlaup activity from the 1821 eruption, so it would be reasonable that at least the caldera area of the top of the glacier was significantly melted by that eruption. I don't know of any indication of lava flow activity, like we are seeing, in 1821-23.

@Kaboom (#172) - glaciers have the capability to form very rapidly. At Mount St. Helens, a glacier formed within the crater left after the 1980 eruption, around the lava dome that grew in the center of the crater between 1980 and 1986, and by 2004 it was already well developed. So it took less than 20 years to form.

en.wikipedia.org/wiki/Crater_Glacier

Thanks Andy. I was hoping to find some sort of gauge on the last eruption but we'll probably never know. At least that won't ever be a problem again i know more about this volcanic eruption than i do about my wife :D

Wow!!! What a difference a day/night makes! What a hole!

Good morning all. It is 6:54 on the left coast this morning as I write. I can't believe what I am seeing! I will have to read to catch up and see what you are all saying. It is amazing to me.

I can't stay long because of appts. :-( But I will be back when it is dark.

Have fun watching.

By Diane N CA (not verified) on 04 May 2010 #permalink

Thank you Boris, I'm amazed at how quick they grow back to be honest but in a way this is good news to me too as when the earth enters a cooling period again all the glaciers that are melting should hopefully be replenished alot quicker than i previously thought.

Looks like we have two new sandbars in the meltwater pool. Could landslides from the 'gravel' slopes trigger the seismometers and record as small high-level earthquakes?

By beedragon Canada (not verified) on 04 May 2010 #permalink

This interaction between glacial erosion and volcanic rejuvenation is interesting.

I assume a glacier will erode the path of least resistance in its descent down a volcano, thus taking out any beds of ash first and avoiding hard lava flows. (is this correct? Or are glaciers such monsters they just bulldoze their way down the mountain regardless?)

Then, when an eruption occurs, the lava also takes the line of least resistance, which in this case is the glacier itself, thereby filling the wound caused by glacial erosion, thus what was once ash gets replaced by lava. Quite a neat little interplay when you think about it.

Guess this is obvious, just never occured to me before.

By bruce stout (not verified) on 04 May 2010 #permalink

I remember the original fissure eruption stopped suddenly after a series of earthquakes blocked the lava conduit and the pressure transferred to the second larger eruption 5k to the west.The tremor has dropped dramatically as before so maybe it'll happen again or perhaps it is the beginning of the end.

@Hans#52
Better not hope for anything happening in the Tindfjallajökull....

Still following this blog on and off - exiting!

By Heidi Ritterbusch (not verified) on 04 May 2010 #permalink

@Henrik, Kerlingafjöll are there own volcano. But they line inside the fissure swarm of Hofsjökull. But Hofsjökull is so big volcano that inside it there is a another volcano in its own right there also.

The view of Eyjafjallajökull is quite interesting today I must say.

@Zander Sounds to be a good explanation: The tremor has dropped dramatically as before. I think this is the beginning of the end, but I hope I´m not right because the volcano show is so great!

By Thomas Wipf (not verified) on 04 May 2010 #permalink

very impressive view on the Hvol cam

Very impressive from the Hvolsvelli cam at the moment. Also Mulakot. Good "stand-back" views rather than the relative close-ups from Ãórólfsfelli or Voda cams we've been glued to.

By Anne in Scotland (not verified) on 04 May 2010 #permalink

@Jon What is your take on this situation the beginning of he end or the end of the beginning? I scarcely believe she is done. Her magma chamber may be emptying but she is finding new paths to refill it.

Am I seeing things, or is there perhaps another opening forming on the left side of the glacier tongue? There's a persistent wisp o' steam over there.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

@193 Does it change at all?
Ref. collapse of ice bridge, I'm comparing to static.panoramio.com/photos/original/13260384.jpg and wondering what's really back there - can see top of opening is 'solid' rock...makes a good mystery...

By birdseyeUSA (not verified) on 04 May 2010 #permalink

The key for me is watching the GPS measurements. If deflation stops or reverses, then it is filling again. And while tremor has dropped from what it has been recently, it is still fairly high in a longer term context. It is about the same right now as it was from 18 to 21 Apr.

To attempt to predict what it will do tomorrow or next with any certainty is a crystal ball project best left to Lady Sofia up the street. What one could say with reasonable accuracy is that the potential still exists for a continued eruption and that anything can happen. It could simply stop tomorrow and go quiet for a couple of hundred years or the eruption could increase or stay the same.

Yesterday's deep quakes followed by shallower ones: en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/#view=table might indicate new intrusion into the magma chamber. The problem is public access to timely GPS data. What data I have access to is old and spotty.

Looking at the various cams, it looks like a new pulse of lava could be flowing.

I do see the spot you are speaking of and I think sir, you are very correct. Take alook on the right side also I think I see on there also.

@193 Kultsi I see what you are talking about. At first I thought it was clouds. But I believe you may be right, but it's difficult to find the source. It seems to be shifting and all the shadows play tricks on the eye.

The spots are always the same and they emit steam on and off

#193

You could be seeing interaction between a lava flow and ice which appears to have picked up considerably in the past hour or so.

On the Poro cam the one on the right side is visible

Here's something to contemplate, if the eruption continues at its current effusion rate for more than a year of so, like Kilauea, it's not unlikely that the lava flow will not just start paving the valley floor, but will also divert or dam the river Markarfljot, creating a new lake.

steam emerging way to lower left of Thoro cam, down near bottoom of screen

By birdseyeUSA (not verified) on 04 May 2010 #permalink

The front of the slope, below the main ash plume, is steaming up pretty good today. Perhaps with the meltwater channel being plugged from the glacier collapse, the lava is spreading out sideways. There's very little coming out of the meltwater opening this morning.

By beedragon (not verified) on 04 May 2010 #permalink

#199 Not on the left side of the glacier, this far untouched. It coulda been a contrail - they are deceiving, but the collapse/opening the trench seems to be advancing across the glacier now, and I think there's a depression all the way across the glacier, with the collapse advancing from right to left.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Wow ... what a different scene after 8 hours of sleep. The summit and higher sections of the glacier/icefield look very depleted - looks like a huge amount of ice has melted and everything else is covered with ash. The harmonic tremors have decreased so perhaps the mountain is now reducing its activity. OTOH the deeper EQ's yesterday may indicate that something may be welling up in the deeper plumbing below the magma chamber.

Stay tuned and we will find out. At least all the action is where it is supposed to be. Last night I was concerned that long dormant Tindfjallajökull was lined up along where the EQ's were occurring. Perhaps some of the EQ activity was due to jokulhaups and so we need only worry about Eyjafjallajökull.

sorry, midscreen level, i was on zoom - totally new place, i think, not near the outlet at all

By birdseyeUSA (not verified) on 04 May 2010 #permalink

it's about in line above the two vehicles, the other side of the moraine ridge, has been coming and going,definitely not cloud

By birdseyeUSA (not verified) on 04 May 2010 #permalink

No definitely not cloud

they're not vehicles, I guess, but two big rocks where the road is - would I guess be widest margin edge of old ice?? if I knew how to post a screen shot reference I would.

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Steam emission looks impressive at the moment from Thorolsfelli cam compared to this morning.

@doug mcl, #201: "but will also divert or dam the river Markarfljot, creating a new lake"
It could be quite the opposite too. The lava is cooled and dammed by the flowing water.

http://pubs.usgs.gov/gip/heimaey/heimaey.pdf

Seems like the power of water is far from negligible, imho.

on Hvolsvelli there appears to be a different (new?) plume rising behind the very active black smoker
also on Ãórólfsfelli between the black and main (currently) steam plume there is a new plume showing when the wind allows a view
on/myndavelar slightly to the left of the black plume and decidedly behind it

Birdseye - yes, I noticed that earlier on today - visible here in the picasaweb series for today at No 65 or else at picasaweb.google.com/102175391233488315229/EyjafjallajokullVolcano4thOfMay2010#5467409738738278722

By Anne in Scotland (not verified) on 04 May 2010 #permalink

It's clear that the lava trench received a big, new deposit of the hot stuff.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

If all you were watching today was the lower of the two vodafone picasa pics, you'd never know Dante's Inferno was taking place just above it.

By beedragon Canada (not verified) on 04 May 2010 #permalink

I am certain I can see a small steam plume now coming out of the glacier half way between the ice arch at the top of the main water outflow and the bottom of the main collapsed area. It is very small just now but can be seen on Mila Thorolfeflli cam.

wonder if some of the melt is now discharging in the next drainage to the left - can't really tell from cams

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Just a brief note on Icelandic grammar :-)

I've noticed people referring to the "Hvolsvelli" camera - there's no such place - it's a bit like saying "have you met my friend John's?" - it ignores the declension of the noun. The proper names (nominative case) of the cameras are:

Hvolsvöllur (Hvolsvollur)
Ãórólfsfell (Thorolfsfell)
Valahnjúkur (Valahnjukur)
Múlakot (Mulakot)

Needless to say I make this comment only because I know you would want to get it right :-)

@Leifur218, I think we are taking that error direct from the camera page - grammar again, I suppose? modified by the frá?

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Does anybody know the guy on the Thorolfsfell Cam? He's been waving at the camera while talking on his cellphone and drinking a coffee - just like he's at a hockey game. I notice, too, that he's wearing shorts - must be a nice day there! I'm quite jealous.

By beedragon Canada (not verified) on 04 May 2010 #permalink

tremor plots are making a return

@Leifur could you dissect this (from the cam page)
Eyjafjallajökull frá Hvolsvelli i would like the meaning of each word

So everyone goes up, stands in front of the camera...and thinks wow there is a volcano here...I better make a call...

By Scott, sg (not verified) on 04 May 2010 #permalink

#218 Thx, Leifur! I knew those on the web site are inflected forms, but really did not know how to figger out the uninflected (nominative) form.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Just remember he is a native species and we are watching his habitat. Maybe we can get him to fix the Val cam...

I see that the Hvolsvell cam is back to its original position which means we'll have lights in our faces tonight again!

By beedragon Canada (not verified) on 04 May 2010 #permalink

Something collapsed a while ago near the main crater. There's still some extra lighter ash/dirt in the air. On Thorolsfell cam.

"Eyjafjallajökull frá Hvolsvelli" = "Eyjafjallajökull from Hvolsvöllur".

Icelandic has retained four cases, nominative, accusative, dative and genitive.

"This is" Hvolsvöllur - Eyjafjallajökull
"About" Hvolsvöll - Eyjfjallajökul
"From" Hvolsvelli - Eyjafjallajökli
"To" Hvolsvallar - Eyjafjallajökuls

End of lesson :-)

Why is it that those doods on the webcam are most often talking on their mobile phones?

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Its too far to yell LOL

they're calling all their friends to say 'look at me,' and, 'take a screen shot in case it's not on picasa.'

By birdseyeUSA (not verified) on 04 May 2010 #permalink

@230 Odds of finding a landline phone on the top of a mountain are pretty low :)

By beedragon Canada (not verified) on 04 May 2010 #permalink

... I'm happy as long as they don't scribble "Kilroy was here" on the lens ...."

@#230: I can barely live with it as long as the muppets are not mooning us... :)

I think it would be funny if someone stood in front of the web cam with a sign that said "Look Ma! I'm on Scienceblogs.com/eruptions!"

By beedragon Canada (not verified) on 04 May 2010 #permalink

Tremor is on the way back up again.

frá Hvolsvelli above the clouds a huge plume much more energetic than the black plume frá Ãórólfsfelli has any one said a new vent opening

Name and location kept private to protect the guilty...but I was somewhere with someone, when I looked around at a popular tourist spot and they were holding onto a security cctv camera and looking into it. I asked what the hell they were doing..."I am looking for where the coin goes in this stupid telescope..."

God knows what that looked like to the people having to watch.

By Scott, sg (not verified) on 04 May 2010 #permalink

I'm happy as long as they don't scribble "Kilroy was here" on the lens ...."

Leifur, you can remember that!

By Grothar, Florida (not verified) on 04 May 2010 #permalink

Interesting interaction between the black eruption column and regular cloud. It's as if the ash column swallows the cloud and then expands enormously, changing its colour to medium-light grey in the process. Any volcanologist who could shed light on this phenomenon?
(1645 GMT, Hvolsvöllur camera.)

By Henrik, Swe (not verified) on 04 May 2010 #permalink

How many does think that the lava may break thru tonight?
Well....I suppose it`s the next step or?

The four forms for Valafell and other names that end in -fell (and -fjall): -fell / -fell / -felli / -fells.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

Another earthquake, this time a little to the northwest
Tuesday 04.05.2010 16:35:23 63.696 -19.705 1.1 km 1.3 47.43 11.2 km W of Básar

By Alison, UK (not verified) on 04 May 2010 #permalink

Hi all, I have been watching here since the beginning of this eruption and posted a few times. I have been on the road for the last two weeks straight and been so thankful to be able to get the real news from all of you. Many, many miles, and many, many thanks.

All of you have been so awesome for everything from some very creepy haiku (no offense) to the actual stats on this amazing volcano. However, I want to see if any of you know of a science blog simliar to this one for the tracking of the oil spill in the Gulf of Mexico. Understanding that no other blog is as good as this one, I have had one huge question since the oil spill began, and I want to keep my neutral friendly status on this board. Thank you.

By Corporal_E (not verified) on 04 May 2010 #permalink

Sorry... I meant of course Ãórólfsfell. But for Valahnúkur it is: (Sing.) -hnúkur / -hnúk / -hnúki /-hnúks. (Pl.) -hnúkar / -hnúka / -hnúkum /-hnúka.

Aside: This is one reason why Icelandic is a lot less dependent on word order than English.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

small note:
When ice melts under ash all the ash that fell is still there... it doesn't go away. So the melting glacier reveals all the ash that ever fell on it. It's showing past ash too not just this last night's ash.
Ask me how i know....;)

Best!motsfo

#248: The hard way?

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

a half-hour behind a lawnmower earns me another 3 hours here? lol
Question -
www.earthice.hi.is/Apps/WebObjects/HI.woa/wa/dp?pictureID=1016377&id=10… shows the full width of the glacier. Where the little left side steamers are showing from time to time seems to be below the leftmost part of the glacier seen in this shot. Could melt be working across under the glacier and exiting far left? Looks as though it drains in about the right place...

By birdseyeUSA (not verified) on 04 May 2010 #permalink

The wind seems to have changed direction, I think we are going to lose our amazing view soon. Somebody, quick, get out the giant fan.

At times it almost looks like there are ash lenticular clouds forming around the plume. Absolutely amazing.

New earthquake right in the caldera:

04.05.201017:28:3463,628-19,62112,4 km2,290,038,8 km SV af Básum

It seems to me that the ash output appears to have increased on the Ãórólfsfelli cam at the same time the new earthquake in the caldera went off.

By Corporal_E (not verified) on 04 May 2010 #permalink

and the steam dropped off too

By birdseyeUSA (not verified) on 04 May 2010 #permalink

has the ash changed content or is it just the light making the color change?

By birdseyeUSA (not verified) on 04 May 2010 #permalink

I just started the creation/upload process for a time-lapse animation from today. I don't know when it will become online, might take an hour or two.

#245 Try the http://www.theoildrum.com. One of the best online sources of discussions on Peak Oil, the oil industry and our energy predicament. They have a number of discussions on the current spill.

It is a whole new rift of whit steam coming up to the right? Must be hundreds of meters!

#259 I think it's just a cloud. lol

Look like Lady Eyja closed the curtains for today. Actually, viewing was better today than could be expected in the morning.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

#258 Thank you Karl UK!

By Corporal_E (not verified) on 04 May 2010 #permalink

#260

Wait until the fog clears. I dont think clouds rise from within the bedrock. :)

#263 take a look at picasaweb photo #91.. If that white line is what you mean then it is cloud... Mulacot cam shows clouds along that line too.. :)

It does not rise from within bedrock but does appear from thin air at that level.. has been doing it all day..

I could be completely wrong of course.. lol

You know, Shelly, i was thinking it was cloud too but then i took Your advice and went to Mulacot and there does seem to be a dark/greyer puff of ashey 'stuff' at the upwind side of that long grey cloud.
Best!motsfo

And of course i can't see it NOW.
but it was there.. honest... really... ok, i'll sit down now.
Best!motsfo

#259 I saw it to Daniel, definitely not cloud, a steam plume came from midway up on the right.

Has the ash production from the crater stopped. From the view I can see at the moment I feel I ought to be able to see the plume but it's gone.

I think there was just a landslide from a new steam vent developing on the moraine face to the right of Gigjokull. It was half hidden behind the fog bank, but I'm sure I saw something move. Interesting to see if it triggered an earthquake reading.

By beedragon Canada (not verified) on 04 May 2010 #permalink

Make that 3 more EQ's!!

I wanted to see this program, Planes, Volcanoes & the Truth from BBC, but it was only for UK residents. Anybody know a mirror site or other way to see it?

By snotra viking,… (not verified) on 04 May 2010 #permalink

Hah! But did the EQ trigger the landslide (if there was one and I haven't just spent too much time looking at wafting fog), or vice versa???

By beedragon Canada (not verified) on 04 May 2010 #permalink

Yes there are indeed more EQ´s. And a a great depth aswell. Last one was at over 14km depth. Makes one wonder what is down there. How big the magmachamber is.

It's on the voda cam, midway up on the right :

17:55 small whisp, 17:56 gets bigger and so on until at least 17:59. Wind from viewers right to left, and no sign of cloud coming in from the right, plus the base of the steam stays static on the rock.

check the mula cam...

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Hmmph... I was sure enough the lava stream was about to break out of the valley to get to the milk shop and buy a Jökull (Glacier) beer.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

thanks Kaboom
I´ll try that.

By snotra viking,… (not verified) on 04 May 2010 #permalink

I see our dumbass hacker is back. Hopefully it won't take Mila too long to clear the screen ... sigh...

By beedragon (not verified) on 04 May 2010 #permalink

Duh! The video server running a self-check! Now I've seen all...

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Why doesn't MÃla go that extra mile (pun extremely intended -- mÃla=mile) and put these cams through a Linux or BSD box?

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

email mila@mila.is and beg for them to clean up the screen!

By beedragon Canada (not verified) on 04 May 2010 #permalink

Re the HP Support assistant the eldgos.mila.is/eyjafjallajokull-fra-fimmvorduhalsi cam

I think the the important action to take is to uninstall it!!!

Right where we are looking to... Blimming thing...

Oh well i was hoping to see some action tonight after the great weather today.It's a shame because the cloud must only be 500 feet thick.

Airspace over Scotland and Northern Ireland closes at 07:00 am tomorrow morning because of ash cloud - BBC

By Anne in Scotland (not verified) on 04 May 2010 #permalink

That cloud you see moving into the Ãórólfsfell webcam image from the right. It's remarkably stable but be assured it is nothing else than a weather cloud. It's at the same level that a more complete cloud (fog) bank was covering the valley floor earlier today. There are no fumaroles (steam vents) or other sources of volcanic gases outside the caldera and the parcourse of the lava flow. What is interesting is how this cloud disappears just above the river, in front of the disintegrating glacier. That's probably due to the higher temperatures in that area. We've seen how dense fog dissolved around Etna's summit when there were lava fountains, the heat apparently prevented condensation in the area close to the hot lava jets, and so you would stand in that sort of a huge open corridor surrounded by dense cloud and see that fountain ...
My impression is that this eruption is not yet over and not even close to being over. All eruptions that last for some time go through periods of higher and lower activity. It's never stable and regular. But we will see ... for the moment it's again quite beautiful and relatively harmless (apart from the ash falls which are a nuisance for people living nearby and which still threaten air traffic to some degree). So I guess we'd all love to see this last for some time, especially if the lava eventually decides to come down that valley with the doomed glacier.

On the evening news they warned of the danger of pyroclastic flows - the paranoid among us would claim that this is just another way to keep us away from the area :-)
I think the authorities are mostly afraid of repeats of the sprained ankles, dislocated shoulders, broken fingers etc. that the trek toward the Fimmvörðuháls ("Five-Cairn Pass" for the linguistically curious) eruption caused ...

@Leifur (#289) - the warning of pyroclastic flows is not as stupid as it might seem. We (that is, a few colleagues from different countries and me) have recently discovered that explosive interaction of lava flows and snow or glacier or simply wet ground can produce pyroclastic flows even at many kilometers of distance from the actual eruptive vents. We've seen this at Etna and Kliuchevskoi on various occasions, and probably also at Llaima in 2008-2009, and it is possible that this also happened during the first (basaltic) episode of the current Eyjafjallajökull eruption at Fimmvörðuháls. So if there is warning of pyroclastic flows, I would take this extremely serious.

the new report is out, notes some of the things we have seen
en.vedur.is/media/jar/Eyjaf_status_2010-05-04_IES_IMO.pdf

By birdseyeUSA (not verified) on 04 May 2010 #permalink

The flow rate of the river has dropped of significantly ... is the melt water being blocked in the glacier?

By Jon Newfoundland (not verified) on 04 May 2010 #permalink

Today's Iceland Met office update:

Assessment 04 May 2010 19:00
Plume was observed at 5.8-6 km height (19-20,000 ft) estimated from the Icelandic Coast Guard (ICG) flight at 10:40 and 15:30 GMT. It is heading east-south-east to south-east from the eruption site. Plume track clearly visible up to 300-400 km distance from the eruption site on a NOAA satellite image at 13:13 GMT.

Water levels have been rather constant. Water temperature at Markarfljot bridge was low this morning (below 2°C) but seems to be rising (about 5°C at noon). Water level seems to be slightly decreasing.

Lava is still flowing northwards, forming a lava fall down the steep hill under GÃgjökull, about 4 km north of the crater. Blue gas is seen rising from the lava and white steam plumes are seen somewhat lower and mark the front of the lava stream. The size of the eruptive crater is 280 x 190 m. Lava splashes are thrown at least a few hundred meters into the air.
Overall assessment is that it is more explosive activity and ash production than was observed yesterday. Progression of the lava seems to be slower than yesterday.

Presently there are no indications that the eruption is about to end. No measurable geophysical changes within the Katla volcano.

By beedragon Canada (not verified) on 04 May 2010 #permalink

#289,192: Isn't this how pseudo-craters form?

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

I should have said ... the flow rate of the river appears to have dropped off significantly.

By Jon Newfoundland (not verified) on 04 May 2010 #permalink

@Leifur (#289), Boris (#292) I took several screenshots on the 17th which seem to show exactly what Boris describes - a dense plume that barely got above the rim picked up several kilometers in height AND rolled down the slope ominously reminiscent of films of pyroclastic flows after contact with the snow ~1-1½km downslope from the vent. Let me put it this way: I wouldn't go close just to find out if it was a pyroclastic flow or not...

By Henrik, Swe (not verified) on 04 May 2010 #permalink

Hi all again and Erik our host, who is so light-handed with this blog. Thanks for that. Great work.
It wasn't my attention to spark off and uncover a poetic streak in the audience, re. limericks.I have to say, however, I love all the effords made, and Iam impressed. Just shows, that we scientists do have a bit of humor inside ... if we hadn't, how could we survive our various quests...?
thanks for all the great updates. Feels like being in Iceland again, which for me will not be in the next couple of months :o( due to thesis work on a very different and only marginally related matter.

@290 Philipp - super time lapse again, many thanks for the time you must spend doing this every day (almost). It really emphasises the change that occurs throughout the day - that you can't really appreciate just watching. I learnt a lot from todays and realised I was wittering in an earlier post about a possible new feature to the east of the main vent - I realise now that it was a neat atmospheric trick of warm, moist air from the steam vents being dragged over the peak to the east and condesing on the leeward side forming a dense cloud.
Just as much as the eruption I have enjoyed watching the atmospheric effects of sddenly warmed air being made to do rather strange things by the tortuous air currents being created by this eruption. A cloud-watchers paradise - except when they hide the view of course.
Many thanks again, Philipp, keep them coming, please!

By Anne in Scotland (not verified) on 04 May 2010 #permalink

When I belittled the danger of pyroclastic flows I was being facetious - anyone who has seen the 30 metre thick ignimbrite layer in Ãórsmörk (from the time Tindfjöll blew up I think) knows that they CAN happen.

I still want to take the chance :-)

May is the fog month in Iceland in my opinion. But this eruption appears to be changing. Maybe to more explosive type of eruption ? How knows at this point. The deep earthquakes are really interesting, I am keeping a eye out for that at the moment. Harmonic tremor still shows up on my plot, but a lot less then before. But it is still there, and it fluctuates it seems.

No TV-documentaries for me... I live in the wrong country... anybody else has a link for me?

By snotra viking,… (not verified) on 04 May 2010 #permalink

@JDZ, That is a false earthquake (ML3.8). I know, it didn't appear on my sensor that is located in the SISZ close to Hekla volcano.

After the last ML2.1 earthquake in Eyjafjallajökull the harmonic tremor started to rise upwards again.

She's barfing: the big mouth-like opening on top of the split rock expels stuff in gushes. It could be ice chunks or gushes of water.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

Scottish and Northern Ireland airspace to close again from 0700hrs tomorrow. http://news.bbc.co.uk/1/hi/uk/8661096.stm. Possibility no fly zone may be extended south. Also noticing a light dust covering down here in East Anglia this evening, very light at the moment but definitely ash, like a covering we had two weeks ago.

Quite a large number of EQ:s around the caldera of EJ now. Wonder if she´s blowing up again, anybody has GPS data that can give us a hint?

I´m curious of course.

By snotra viking,… (not verified) on 04 May 2010 #permalink

Well, my boss just cancelled his vacation/business trip to Amsterdam, England, France, and Ireland.

By beedragon Canada (not verified) on 04 May 2010 #permalink

Well how disappointed am I? I rushed home thinking that the front of the glacier was going to give way, giving us a good view of what's lurking behind. Guess It only goes to prove the following....

volcanolive.com/murphy.html

By christoph (not verified) on 04 May 2010 #permalink

@beedragon #310 My husband is supposed to be flying to Budapest tomorrow. I've told him to take extra undies, just in case he gets stuck there. Luckily, we both work from home, and he's just spent extra time setting up our server here so he can access files and work from abroad if he needs to. We'll see - London may or may not be open for business tomorrow.

@Suw 313, Boss was supposed to leave on Friday, for 2 weeks. Being stuck in Europe wouldn't bother me :) but he didn't want to risk spending a week on a cot in the airport!

By beedragon Canada (not verified) on 04 May 2010 #permalink

@beedragon #314 I really can't say I blame him. I think one has to really be prepared for a longer stay, rather than hanging around hte airport. Friend of mine got stuck in Egypt last time. It was supposed to be a 5 night break, turned into a 15 night break... and he actually works for an airline and couldn't get back.

For some reason they have now started to warn of pyroclastic flow coming from Eyjafjallajökli. I guess there have been enough changes on the ash plume to warrant that warning.

Snotra viking, sweden:
Swedish television (svt.se) will send a fresh documentary about Eyjafjallajökull on "Vetenskapens Värld" next monday. I will definately watch that one :)

By Mattias Larsson, Swe (not verified) on 04 May 2010 #permalink

It would give me a chance to catch up with family in England that I haven't seen for a long time. But I'm stuck here in Ontario.

By beedragon Canada (not verified) on 04 May 2010 #permalink

@JónF Are they mentioning specific areas or just in general?

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Don't know if you were watching on the webcam but a whole lot of steam just started rising up from the ground about 4 minutes ago and is now covering most of the screen. I've been waiting for that, I thought it might be all we saw when the dam finally broke. I think something is flowing through.

@birdseyeUSA, This is a general warning only. But it is directed to GÃgjökull (where the steam comes from) mostly. But they do not exclude other areas. But the area is ban zone at the moment and nobody is allowed to travel there.

@Jen 322 ... Probably not steam. Probably just the same fog that was in the valley this morning. Just when we were waiting for darkness to see where the lava flow has reached. argh!

By beedragon Canada (not verified) on 04 May 2010 #permalink

and there's an annoying little cloud showing over on the mula cam...

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Hah! I saw the quake that just occured (21:44:47) on the Thorolfsfell camera: the tops of Eyja jumped up and down - on a nine km range, the movement need not be much to be visible, and it could not be wind, as there was none.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

#320: One news site (visir.is) quotes Civil Defence on risk of hot gas clouds blasting down the valley not totally unlike the surges produced by Vesuvius way back when.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

..or there was...seems to form and dissipate fast.
Humbug-HP has taken over Thoro cam again!

By birdseyeUSA (not verified) on 04 May 2010 #permalink

@322 and 324 ... the "cloud" expanded from the base of the glacier towards the camera. I don't think it was the fog we were watching earlier ... unless the wind has changed.

Oh My God! Who is responsible for computer updates on Mila. Windows 7 reminder is NOT what i want to see right now. :S

#329, #322 and #324; Jon I thought so too, it definitely rose up towards the camera and formed quite differently to fog.

What is wrong with the MILA cam? I want to see! Please!

HP is torturing me!

I can't get though to vodafone right now, either.

I don´t want to travel away to much from the main subject of this thread but I just cannot stop myself from bringing this Seismo-blog thread up.

http://seismo.berkeley.edu/blogs/seismoblog.php/2010/04/13/an-enigma-de…

Earthquakes at 400 miles depth (!!!) in Spain.

And those extremly deep EQ:s appear to have happened several times during the last century at the same location. The largest was a magnitude 7.0 on March 29, 1954. I have never heard about anything like this before. Anyone of you who have any idea of a possible reason for such deep earthquakes?
Tell me if I´m wrong but as I understand it there are no other place in the world were such deep earthquakes have been recorded.

By Mattias Larsson, Swe (not verified) on 04 May 2010 #permalink

Perhaps just a fairly fast moving cloud bank... the view's not too bad on the vodafone webcam right nwo.

By beedragon Canada (not verified) on 04 May 2010 #permalink

Perhaps Mila just installed a new HP Printer ... they come with some of the worst software add-ons. I have a rogue HP pop-up on my home pc, that shows up out of nowhere.

By beedragon Canada (not verified) on 04 May 2010 #permalink

Keeping the vodafone cam up whilst I get myself, my hubby and the kittens ready for bed in the hope that I'll get a glimpse of lava glow before I retire. My dreams have been filled with Eyjaf the last few nights. Can't imagine why.

If you look at the EQ data on http://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/…
it seems that there are tremors ranging from 1km to 22km depth.

I guess alot of scientists are scratching their heads right now trying to figure out what it means. I mean this could mean anything. All from a vast magmachamber deep deep down or alot of intrusions i guess.

Refering to a previous post by Boris Behncke which stated that it is very hard to interpret such tremors and what they would indicate.

Am I totaly wrong if i guess that there is a bigger chamber deep down fueling alot of different channels on their way up to the surface?

#331, #329, #322 and #324; I was watching the whole thing. There's evidently warm air around the waste pond, as the clouds around it dissipated, then started forming right in front of the camera - condensation of super-saturated water vapor is quite fast once it starts. Very fast the cloud layer spread across the valley - by condensation - and then it rose until it obscured the camera. Just before the mountain tops disappeared, the EQ happened.

By Kultsi, Askola, FI (not verified) on 04 May 2010 #permalink

re Bruce #2 Boluses are depicted in a schematic diagram on the 'cold plume' hypothesis, here (fig14):
http://www.mantleplumes.org/Iceland1.html

Prof Foulger gives no info whatsover on the boluses, but the hypothesis requires little mixing to occur between the mantle bulk and rising ancient subducted remelted Caledonian crust, so there's the inference. Maybe the March spikes are the first indirect evidence for bolistic accretion mode? That's what interests me.

By Peter Cobbold (not verified) on 04 May 2010 #permalink

Mattias Larsson, Swe there was an earthquake like that in Russia a couple of months ago....so they do happen at other places at that depth.

Daniel you may be right or you may be wrong....right now I think it is anyone's guess as to what is down there....I think that is why Boris said it was hard to interpret such tremors and what they indicate....they are scratching their heads a little now but working on an answer;)

re
http://en.vedur.is/earthquakes-and-volcanism/earthquakes/

The rolling plot of EQs underneath the map has superfluous colour coding (the plot itself gives age of EQs) I would find it really useful if the colour coding described EQ depth.
Any one else agree?

But thanks Jon #1, 18km is deep. Mantle-crust boundary there is measured at approx.20km ( see URL in #340)

By Peter Cobbold (not verified) on 04 May 2010 #permalink

I just called some guy on duty at Mila's surveilance center and told about the Thorodsfell camera situation. I promised to try to call the dude responsable for the cameras. Dunno if that will fix the problem - alas something was done.

By Sigmar Reynisson (not verified) on 04 May 2010 #permalink

Upps!
HE promised to reach the guy.

By Sigmar Reynisson (not verified) on 04 May 2010 #permalink

@Peter #342 There's a lot that could be done to represent the EQs in a variety of ways beyond what the Iceland Met Office has the time to do. It'd be nice if they released the information as a geo-RSS feed with precise location, time, depth, and whatever other information they have, all labelled up semantically so that people could do something with it. Be even better if that feed was historic with, say, the last year's worth of data in.

The Icelandic Met Office is incredibly generous with its data, and it's great to see such a rich resource. It'd be even more wonderful if they could release RSS feed and maybe even an API so that curious programmers could do something interesting with that data.

@Sigmar Thank you! This happened earlier today and only took them about 15 minutes to fix. This time it's been up a bit longer. Hopefully they can clear it while we still have light!

By beedragon Canada (not verified) on 04 May 2010 #permalink

Thanks Randall. Where in Russia did it occure? I wonder what the reason for those events could be. In the article they write that very deep EQ:s can happen in subduction zones, but there are no subduction zonen anywhere near Granada in Spain. I find it very interesting that the deep events have happened at exactly the same place several times. I find it very amusing to think about these kind of things, and want to figure out possible reasons for those EQ:s.
I guess there is time fore some web-research :)

By Mattias Larsson, Swe (not verified) on 04 May 2010 #permalink

Mattias Larsson, Swe I think it was along the Chinese/Russian border but it has been a couple of months so you may have to look at archived info to find it. I don't think quakes at that depth are real common but they do occur. Here is a good place to start your research;)
"The deepest earthquakes typically occur at plate boundaries where the Earthâs crust is being subducted into the Earthâs mantle. These occur as deep as 750 km (400 miles) below the surface."
earthquake.usgs.gov/learn/facts.php

Eruption (lava fountains?) viewable on Hvolsvell webcam right now.

By beedragon Canada (not verified) on 04 May 2010 #permalink

"but there are no subduction zonen anywhere near Granada in Spain."

Depends on your definition of "near". The Africa is subducting under Spain.

@Suw It never ceases to amaze me that a country of just one third of a million souls has created the planet's only whole-nation real-time EQ map.
I do hope IMO archive their data as the EQ oscillations in march were astonishingly symmetrical and eventually someone in the profession will get interested in them. No signs of that so far so I'll keep trying.

By Peter Cobbold (not verified) on 04 May 2010 #permalink

Still got the WinSlow$ sign, but the HP screen is gone on Thora.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

Thanks Randall!

"The deepest earthquakes typically occur at plate boundaries where the Earthâs crust is being subducted into the Earthâs mantle. These occur as deep as 750 km (400 miles) below the surface."

That would be at the subduction zones then :) I found this interesting info to http://geology.about.com/od/earthquakes/a/aa_deeEQs.htm

By the way, there is an interesting lightshow on the Ãórólfsfelli webcam now eldgos.mila.is/eyjafjallajokull-fra-fimmvorduhalsi/

By Mattias Larsson (not verified) on 04 May 2010 #permalink

Great blog. First time poster, here. Porolfsfelli cam showing the lava in the glacier. Almost looks like a new vent its so strong.

I always do a nightly check on Katla. It looks different tonight. Can anyone tell me what the white glow is on there? Would it be snow reflecting? I've never seen it before. Usually it's all black with tv like "snow".

By Janet, Texas (not verified) on 04 May 2010 #permalink

Thorolfsfell webcam back up and showing incandescence.

And, honest, there were HUGE lava fountains on the Hvolsvell webcam before the clouds came back :))

By beedragon Canada (not verified) on 04 May 2010 #permalink

#357: Looks like glow from the northern sky. We're in the 'not quite dark at midnight' period of the year.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

did anyone notice the two small lights that came up at the lower right side of Thoro cam??Vehicles?? could they have been on the far side of the river...?? in the dark??

By birdseyeUSA (not verified) on 04 May 2010 #permalink

@birdseyeUSA I saw the lights too! Would people be dumb enough to try and sneak up there in the dark?

And I have to edit my earlier post ... Strombolian eruptions, not lava fountains, at Hvolsvell. I hope that the clouds will move off so we can see them again.

By beedragon Canada (not verified) on 04 May 2010 #permalink

@BrianD welcome- we had an interesting exchange a while back about spelling and names and languages; Icelandic uses Th for à rather than P ... we're all practicing! : )

By birdseyeUSA (not verified) on 04 May 2010 #permalink

#357: Looks like glow from the northern sky. We're in the 'not quite dark at midnight' period of the year.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

I just saw the little light again. If that is people, I hope they know that there were landslides on the moraine today!

By beedragon Canada (not verified) on 04 May 2010 #permalink

B4y wireless keeps b4y falling off the b4y network.

By Reynir Heiðbe… (not verified) on 04 May 2010 #permalink

Brian, that is not a P, it is a à or "thorn" ... and translated to english would be Th so Thoro... not Poro...

English had the same letter until somewhat recently (in geological time :) and it often superscripts would be added to make words such as an e for "the" and would look like this: Ãe . Often the thorn would be typeset as a y and so that became ye and that is how ye Olde Candy Shoppe came to be. It is really "the".

Thank you Reynir! Being in Texas I'm not used to the "not quite dark at midnight". I appreciate the answer.

By Janet, Texas (not verified) on 04 May 2010 #permalink

Thanks for the correction, guys. Thoro it is.

Hi everybody, is the glow on Thorolfsfell actually sometimes blue or green, or is it a trick of the camera?

Ok, I think the lava will emerge from under the glacier on Saturday May 8th.

My reasoning?

Te distance from the crater to the foot of GÃgjökull is approx. 4 km. Yesterday scientists estimated that the lava flow has about a kilometre and a half to go to reach the GÃgjökull water outlet. It has taken the lava flow an awfully long time to travel two and a half km. A lot of the energy goes into melting ice.

The Eyjafjallajökull icecap is not thick, only about 250 m at its thickest. Presumably the lava has worked its way through the thickest part and is now flowing downhill under a much thinner glacial roof. So the pace should pick up a bit by my reasoning.

Anyone interested in placing bets on when the lava will appear in the Markarfljót basin?

By Anna, ReykjavÃk (not verified) on 04 May 2010 #permalink

@370 Irna That's a trick of light. Seen it a few times when the glow gets distorted by steam clouds, and even regular clods at times. Prism effect probably.

Dan, thank you for the explanation.

Anna, I think it will arrive sooner if the eruption continues at its current pace.

I say by Thursday.

@George (#374)
It'll be interesting to see. It's already Wednesday here in Iceland so you're saying tomorrow :)

By Anna, ReykjavÃk (not verified) on 04 May 2010 #permalink

#376 Anna
Personally I'm Clueless about when it breaks thur but it is Tuesday, 5 pm Pacific NW US time. Currently Wed. your time.

So you are saying Saturday Icelandic Time the lave will hit the former lake bed - got a GMT (time)?

It could be caused by different minerals in the plume / clouds gasses from the lava

Anna, yes, I forgot about the time difference. It is only Tuesday afternoon here :)

So to put a finer point on it ... sometime between 24 and 48 hours from now is my guess.

I thought the entire mediterranean basin was a subduction zone, just that there is more movement around ellada than espana.

#377 JB US
I'm just as clueless as you are (I'm sure even Boris B., the resident specialist, couldn't be goaded into making a prediction).

But I'll say 21:00 GMT.

By Anna, ReykjavÃk (not verified) on 04 May 2010 #permalink

George, Eddie. You might be right about the subduction zones. http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/Maps/map_plate_tecton… I found an old article that refered to deep earthquakes under spain as a indication of deep subduction occuring. I am a little bit confused about the article about the deep Granada earthquakes. I found it strange that somebody would write that no subduction zone is known in the area, if there is indeed a known subduction zone there. I have to do some more research on this subject. Meiby I drop a note here when I have gathered more info :)

By Mattias Larsson (not verified) on 04 May 2010 #permalink

Well ,I finally got back after hours in town. I did get to see some of the activity and they zippo, nada. When I tried to go to the Hvo(something or other) and I got that HP nonsense. Oh well...

I am going to take a wild guess at when the lava will reach the crevice: say about 36 hrs. My initial guess would be 24hrs, but I think it will take longer than that. I really have no idea. :-)

@Randall, off the subject, I tried to email you and I got a no delivery thing(I will have to check with my server on that) and I did with someone else also when trying to email about a "hands and pans only" ruling here. Anyway, we were able to get them to withdraw the ruling. We did a major writing campaign and it worked. I ask you, how do you dig out a crevice with your hands when it is only about an inch wide?!! But now that is behind us for the time being. I am hoping to get to the river sometime soon.

Anyway I hope the clouds and fog will go away so we can see something. At least I can see morning in Iceland at about 8:30pm here. Lets hope we see something cool!

By Diane N CA (not verified) on 04 May 2010 #permalink

Diane N CA really...it shouldn't have come back can you resend it? I have an email that I have been working on for you with links to info on gold locations in Alabama, Georgia and one of them has a lot of info for all 50 states. I have been so busy lately with work that I haven't been able to do anything much except go to the beach on Sunday...to say goodbye to an old friend:( I am going to go ahead and send what I have now and more later.

@381 & 384

Parts of the Med are made up of active subduction zones, the rest is either oceanic or continental convergent zones... which under the proper conditions, become subduction zones. I imagine that what a particular area is or was doing depends on what geological period your in. The Spain/N.Africa area shows as a Continental convergent zone turning south into the corner N.Africa about 160 km SE of Gibraltar. (per USGS Goog Earth Plugin)

Randall, it had to do with something in my email that looked like spam to the servers. I got it with another friend of mine. I am not sure what happened so I will try to reword it so it will go though. I think it may have to do with the words regulation or ruling.

Thanks for what you are going to send. I understand being very busy with work.

Sorry gang about being off subject. The issue was a ruling by the California State Parks involving 55miles of river and they were issuing a "Hands and pans only" rule for gold panning. Totally ridiculous! We were able to get them to withdraw the ruling. It was done in an underhanded way with no public hearing for public input.

Well enough of that. Does anyone know what is happening on Eyjaf now or is it still all clouded in?

By Diane N CA (not verified) on 04 May 2010 #permalink

On the subject of deep EQ's, there are three locations I can think of off-hand that have EQ's deeper than 500 kilometres: the Salta, Argentina vicinity (East of the Andes); West of the Kamchatka Penninsula; and East of Vanuatu in the Pacific. These are all related to subduction.

@DianeNCa -looks dark all over - look at Picasa towards dark and see two little lights toward bottom right and later one higher up - looks like someone hiked up there or drove up. Maybe going for night shots? There were a couple of good explosions visible at one point but I don't think Picasa got them to full effect. tremors headed up again but at lower levels. New reoprt in, click on the fuller report there are more details.
Eyja is tossing and turning in the dark,but I'm turning in- now you keep watch!

By birdseyeUSA (not verified) on 04 May 2010 #permalink

Birdseye, I will just keep watching because in about an hour, I will be able to see something if the clouds go away. Have a good sleep.

By Diane N CA (not verified) on 04 May 2010 #permalink

From the abstract of a paper that a quick goggle turned up:

In this paper we present new results concerning the existence and subduction of Meso-Tethyan oceanic
lithosphere in the upper mantle beneath Europe, the Mediterranean and the Middle-East. The results arise
from a large scale body wave tomographic analysis of the upper mantle in this region. It is shown that much
more subduction has taken place beneath the Aegean and Tyrrhenean region than was previously estimated.
The Eastern Mediterranean basins are linked to the old Meso-Tethyan passive margin and may in some parts
be underlain by oceanic lithosphere. We demonstrate the existence of an old northward dipping subducted
slab beneath Spain and the Western Mediterranean. A large zone of suhducted oceanic lithosphere is found
beneath the entire Alpine orogenic belt from Spain to Iran at depths between 250-600 km. This zone
represents major parts of the Meso-Tethys.

W. Spakman 1986

You can get it here:

http://www.njgonline.nl/publish/articles/000327/article.pdf

#384 Larsson, I'm from Brazil and I grew up believing that we didn't have any earthquakes here because we were far from convergent boundaries etc. But then I learned that we had a series of M6+, even M7 quakes in the past, in the Amazon plain. That's because far from the boundary of Nazca plate with S. American Plate we have those very deep so called "deep mantle quakes" (sorry I'm no expert)which still are a mystery to geologists. They occur where they weren't supposed to, because at this depth nothing would be brittle enough to provoke EQs. So they have this hypothesis that some kind of mineralogical chemistry happens that makes rocks become brittle (olivine, I think) and it happens very far from subduction boundaries. Maybe this is the case in Spain. There's a famous M 8,3 La Paz earthquake that was at such depths and many more in Peru and... in Brazil! I was happy because we do have earthquakes (I always envied chileans for that). And they are harmless, but felt from far distances. Uff! Hard to explain it in English, but I tryed.

By Renato I Silveira (not verified) on 04 May 2010 #permalink

Can clearly see on Thorolfsfelli cam the lava glowing halfway down the glacier. It looks like there might explosive activity - or could be glow from steam - hard to tell. Might we see explosive activity in that place?

By Helen Leggatt (not verified) on 04 May 2010 #permalink

I think I missed something in my amateur explanation: the quakes are caused by the subducted plate, but the oldest part of it, far from the spot they came under the other plate - so I suppose those quakes in Granada could be the deepest part of the African plate becoming brittle far underneath Spain, am I right?
And back to Eyaf: I can't see much on the view frá Ãórólfsfelli, just big drops on the lens.

By Renato I Silveira (not verified) on 04 May 2010 #permalink

This is a strange night. The only web sites I can connect to are Eruptions and the Thorolfsfelli camera and its fog bank. 0330 comes early so it is off to bed.

By Doug Merson (not verified) on 04 May 2010 #permalink

@Renato I like "tryed".

It is quaint in a deliciously twisted way.
Goodnight to all and to jökulleyjafjalla all sow well to.

By Raving | Hogtown (not verified) on 04 May 2010 #permalink

1st EQ of the day 1.4 22.7km 4:32:18

By renee chicago (not verified) on 04 May 2010 #permalink

@340 Peter,

Thanks!! What a great paper. I like the way he enumerates the problems with the mantle plume hypothesis. It would be interesting to see how this was received by the geoscience community as it is way above my head to make any assessment. But I can follow his general argument and it makes sense, though it seemed to me that he was NOT arguing in favor of upwelling continental lithosphere but rather eclogite, which is oceanic lithosphere that was subducted to great depth approx. 400Ma when the lapetus ocean closed and Caledonia and Greenland converged. Greater thickness of this material under Iceland and perhaps the odd bit of continental crust explain the anomalous volume of magma erupted at Iceland when compared to the rest of the mid-ocean ridge.

Re the boluses: I take it you took this model from figure 14 showing uprising pockets of melt. I am not too confident about its validity because it is extremely schematic. I have seen a similar diagram to explain the Auckland Volcanic Field, which is composed of untold monogenetic cones where the diagram makes more sense (each cone being one such "bolus") but Iceland seems to be way more complicated.

I would love to know how much melt is pocketed between the mantle and the crust for instance. How hot this might be, how it interacts with the crust, etc. For me, this still remains the main mystery of the extremely symmetric seismic activity prior to the Fimmvorduhals eruption because I think it is an expression of some mechanism by which melt rose from a pond at the mantle/crust boundary and "flooded" through an existing network of conduits and fractures, creating new ones as it went by fracturing rock and so on. The mystery being, why did this happen in nearly perfect waves and not in one steady stream.

BTW, great to hear from you again. Very stimulating.

By bruce stout (not verified) on 04 May 2010 #permalink

On the Vodaphone cam there are the same droplets as in Thora and also strips can be seen on the upper left of the screen. Ashfall?

By Renato I Silveira (not verified) on 04 May 2010 #permalink

And Katla looks gorgeous. There's this dark plume to the left (from Eyjaf or just clouds?). But the landscape looks somewhat lunar.

By Renato I Silveira (not verified) on 04 May 2010 #permalink

I do not like the fluctuation that follows the earthquake on the harmonic tremor levels. I do think it is a bad sign. Whatever is happening at ~23km depth does not show it self on the surface any time soon I think. It might take days or weeks until we see any change from what is happening at he great depth under Eyjafjallajökull.

While things are quiet and 'fogged out', I thought that I might share an exchange from last night...
19 yr old son "surely you're not watching that volcano on your laptop again!"
Me.... "why not?"
Him... "get a life, read a book...do something interesting"
Me ...*shakes head* "it is interesting and very informative; so far I've increased my knowledge on volcanoes, EQs, Icelandic language, air safety and Haiku!"
I dare not tell him that I've resorted to taking my laptop to bed...might get a severe talking to!
But I must thank everyone for their willingness to share information, observations and opinion in such an open and welcoming forum.

By Kathryn, Australia (not verified) on 04 May 2010 #permalink

From the latest report at:
www.earthice.hi.is/page/ies_Eyjafjallajokull_eruption

"GPS deformation:
Irregular oscillations in vertical component of stations next to the volcano."

I'm wondering if that links up with the deep earthquakes. Is yet more magma attempting to push itself up?

@Kathryn: My kids think that I should get a life too. I'll stick with Eyjafjallajökul though! I like the idea of taking the laptop to bed ... now all I need to do is get a laptop.

By Emma, Lancashire UK (not verified) on 04 May 2010 #permalink

I wonder what the error bars are for EQ depth... Seeing as they are reported with 3 digits. I too am puzzled by the deep temblors. My gut feeling is that those quakes are due to built-up tectonic stress that would have been released anyway, but the process is accelerated by the heat- and pressure gradients caused by the eruption. Either that or there really is a significant change in magma flow rate (GPS plots should be helpful).

Another thing that has struck me is that tremor seems to build up, then a deep quake hits and tremor suddenly drops and starts to build up again.

Interesting, all the same.

Has anyone looked at Katla lately. There's a "cloud" behaving rather strangely. It's in the wrong place to be steam from EJ

@mattlee, It's a cloud. Nothing more. You are going to know for sure when Katla starts erupting. It's going to be on the news across Europe when that happens.

GPS readings are indeed strange. Refer to this map:

hraun.vedur.is/ja/Katla2009/Myrdalsjokull.jpg

GPS readings are updated to today:

Ãorvaldseyri (about 7 Km S of Eyjafjallajökull)
hraun.vedur.is/ja/gps/predorb/they_enu_p.png

Sólheimaheiði (about 21 Km ESE of Eyjafjallajökull)
hraun.vedur.is/ja/gps/predorb/soho_enu_p.png

Goðaland (about 16 Km ENE of Eyjafjallajökull)
hraun.vedur.is/ja/gps/predorb/gola_enu_p.png

Lágu-Hvolar (about 42 Km ESE of Eyjafjallajökull)
hraun.vedur.is/ja/gps/predorb/hvol_enu_p.png

Why it's stations closer to Katla that are reporting proportionally higher upward ground deformation?

@ Mr Moho #411

I don't see what you are referring to. GOLA has actually dropped significantly and SOHO is well within its normal pattern of deviation.

By bruce stout (not verified) on 04 May 2010 #permalink

Are you sure you are not reading the North East displacement? Only station showing a slight increase seems to be HVOL. And that is (so far) only a small increase which I would guess is part of Katlas normal huffing and puffing.

I guess it's normal behavior, then.
Sorry everybody.

No worries!! we're all keen watchers ;-)

By bruce stout (not verified) on 04 May 2010 #permalink

About the GPS data. The THEY GPS station is showing interesting behaviour. The North-South is deflating like normal. But there is a huge inflation happening on the East-West (they way the Eyjafjallajökull volcano actually lies) happening. It moved 5mm in ~24 hours or so. Given the early lead up to this eruption, it has become clear that the movement to the East-West is more important then the movement to north-south it seems.

But the North-South has it's role to play in this, that is clear already and has from the start. But the East-West movement appears to be the driving force behind this eruption for some reasons that I cannot explain. Today it just had a big inflation pulse. What happens next is a good guess. But I don't think it is anything good.

@ Jon, I saw that too, but I remember similar "outliers" in the past that were subsequently corrected after a day or two so I tend to wait a day or two before reading too much into the GPS readings. However, if it is correct, you are right, I don't think it is a good sign either.

By bruce stout (not verified) on 04 May 2010 #permalink

@beedragon Canada. You said yesterday or the day before that you have to go out so no screen captures. I did not get to answer this yesterday. I have a program that captures the Vodafone camera - usually even when others can't get on to it as it goes direct to the page, and can also download the Mulakot cam and the Eyja plots automatically. It does not work with the streaming cams however. Basically any static picture it can pick up. I use it for Vodafone, Mulakot, Chaiten, Villarica etc and the tremor plots. (Unfortunately) It only runs on Windows at present, but I am working on that, and the whole thing is work in progress. It gathers USGS quake data and can create sound files from seismo data. I am working on Icelandic data at present - just a matter of time I don't have right now.

It is free so you can have a look and throw it out if you don't like it. It has never been offered to the larger audience so is only used by a few diehards on the Volcano Watch and Quake Watch threads on ATS.

Just at the moment the help files are a bit out of date, but there is a support email address on my site and I would be happy to assist.

The program is called QuakeData, it is FREEWARE, and you can download it from here. http://www.dasoftware.com/qdoverview.html

By David L. Ireland (not verified) on 05 May 2010 #permalink

@Jón FrÃman (#417). E-W drift due to continental rift? Clues: Eyjafjallas E-W elongated shape plus N-S split through the crater? Ie a parallell to the Eldgja and Laki fissures albeit on a much less grand scale?

By Henrik, Swe (not verified) on 05 May 2010 #permalink

@kathryn (405) I too take the laptop to bed, I have to since the interseting things happen when it´s dusk or dawn. Dawn I never see though, it´s colliding with children going to daycare and such. Happy you few who has this, watching volcanos, for a living. I´m sure I would have been a very keen scientist in volcanology. Another life maybe!

But then again "Learning is living", an just as you have, I´ve learned a lot, and intend to follow this as far as it goes, whatever the family says.

By snotraviking (not verified) on 05 May 2010 #permalink

@Kathryn 405 I usually end up having to get up in the middle of the night to go to the bathroom (sorry for the TMI) and it's been really hard for me not to run into the living room and check the webcams, because, you know "it's daybreak in Iceland!"

By beedragon Canada (not verified) on 05 May 2010 #permalink

Hopefully this morning fog will be gone in a few hours, like yesterday.

There were a couple of moments last night where I was able to see some fabulous strombolian eruptions on the Hvolsvell cam. How big does a lava bomb have to be, if you can clearly see it fly through the air, for a distance matching the height of the eruption itself, from 25 km away?!

(I can't do the math on that one, my head would explode).

By beedragon Canada (not verified) on 05 May 2010 #permalink

Can anyone access all the Milu cams today or is it just me having problems? The only one I can get is the Thorolfsfell one and it's just showing fog, the other 2 cameras dont work at all.

By Marginata, Scotland (not verified) on 05 May 2010 #permalink

@424 It's not just you, the other 2 cams are down for me too.

Beedragon, do you have any screenshots from yesterdays lavabombs? Would love to see some.

By snotraviking (not verified) on 05 May 2010 #permalink

@snotraviking Sorry, I don't have any pics. They were only in view for a minute or two before that HP screenshot blocked everything!

By beedragon Canada (not verified) on 05 May 2010 #permalink

If Katla normally goes with little or no notice, are there changes that are not being looked for?

For example, is there any value in monitoring the subglacial temperature of the rock surface? Would it give any hint of a temperature increase prior to eruption?

Does the surface temperature increase prior to eruption?

@dubliner: The problem with this volcano is, that its under a glacier. And you don't know, where its going to erupt next. The things, that can be measured best are earthquakes (if swarms appear people will get cautious) and the movements of the mountain by gps measurements.

@Bruce 401. He's a she! - Foulger is a Prof. at Durham Univ UK. While her boluses are indeed merely a schematic depiction I think they reveal her thinking. She has to explain how eclogite that is not so very much hotter than the mantle bulk rises from depth to the crust mantle boundary. She finds no evidence for heat-driven convection (no hot plume) so buoyant boluses of eclogite that remain distinct (as in lower density and in chemistry) than the bulk mantle seem to be the only plausible resolution.

I guess there's no seismic data on the Auckland Volcanic field and hopefully no new data forthcoming! But I do wonder whether other volcanos lying over the plume in Iceland that are not primed to erupt have shown EQ oscillations in the past(Hymaey? Kraftla?).

I see the symmetry of the each EQ burts being the result of a bolus merging with the liquidus of the lower crust boundary, here at 20km depth. The upward force generated by addition of new buoyant material over a large area is then amplified hydraulically as the force becomes concentrated into smaller area of liquidus penetrating vertically into an increasingly solid volcano mass above the bolus. A bit like brakes on a car- a small force over large area translates into large force over small area at wheel cylinders. Hydraulic transmission and amplification of a boluse's buoyant force would have to be capable of triggering maybe 20 to 70 EQs per hour (as in the largest spike we saw)each of mag 1 to 2. Its beyond me to assess feasibility of that. But to see the effect it would be important that the volcano did not offer an immediate low-resistance liquidus route to releasing the bolus' hydraulic pressure as an eruption. So volcanos with well-formed conduits and magma chambers (eg Hekla)would simply erupt upon arrival of the first bolus rather than show EQ swarms and EQ oscillations. Hence the need to look for EQ oscillations in long-cycle volcanos or maybe fissure eruptions. The logical conclusion of all this speculation is that eruption cycles over Iceland's cold plume could reflect not the local activity within the volcano but the activity of the deep mantle and rising boluses.

Boluses might be continuing to arive under Eyjaf even now. So something we should look for now is oscillations in Eyjaf's eruptive activity. If more boluses continue to arrive under Eyjaf,now that it has a low-resistance conduit formed they would according to the hydraulic coupling accelerate eruptive activity. The few deep EQs seen at present may indeed relect a new bolus arriving. Its impoprtant to recognise that hydraulic coupling does not require that the bolus magma itself rises the 20km to the surface: there may be very little delay indeed (as with brakes on most cars). On the basis of the oscillations we saw in march each eruptive oscillation would have a duration of roughly 36 hours. Unfortunately the small numbers of EQs under Eyjaf at present do not allow us to discern statistically an oscillatory pattern, just hints. What we need is numerical measure hour by hour of the plume's mass. Lots of pictures of the plume I gather: pity there's no numbers. Anyone out there seen time-lapse images showing 36 hour-long bursts of Eyjaf's activity??

If Hekla is also bolus-fed there should be evidence in the literature for oscillatory bursts in its eruptive activity.

By Peter Cobbold (not verified) on 05 May 2010 #permalink

thanks to all you overnighters for your discussion of deep quakes. much appreciated.

By birdseyeUSA (not verified) on 05 May 2010 #permalink

It seems she has entered a quite calm period. Tremors on both Jón´s helicorder page and the one at hraun.vedur are showing significant decrease in tremors.

This in combination with quite alof of deep EQ´s would that suggest a "calm before the storm" and that she has found other conduits and outlets or is it as someone said earlier "Beginning of the end"?

also Fréttir (mbl.is) news about earthquakes yesterday,web translation.

"Seismic measurements now show a new dynamic shots under Eyjafjallajökull.
GPS tracking service and IES support this interpretation. Therefore be expected to market erupted continue unabated over the next day, for the IMO said.

It says that since Monday has been under increased skjálftavirkni Eyjafjallajökull. Accurate earthquake locations show that they first be deep in the earth, at about 23 km depth, but then moves up. This indicates probably that new magma is þrýstast the bottom of the magma channel. She ýti the top remaining magma to pressure change moves up the surface. Therefore be expected to erupt continue unabated over the next days.

Then says that substantial changes in the post-stop around the GPS Eyjafell last two days. At stations BAS2 and STE2, which is just north of the glacier, can now detect a new entry to the north. They moved south of the glacier (Ãorvaldseyri) now to the west, and FIM2 station, which is somewhat further east, the sample transfer to the east.

Distribution skjálftavirkni the magma channel also provides evidence of the location magma chamber that has erupted since the 13th April is believed to be in the 3-5 km depth, where earthquakes have not occurred.

By birdseyeUSA (not verified) on 05 May 2010 #permalink

The IceMetOffice geologists think there's a new burst of magma flowing towards Eyji. There were reports of the rumbles from the volcano being audible far and wide this morning.

By Reynir Heiðbe… (not verified) on 05 May 2010 #permalink

Thanks everybody for all the help about deep earthquakes! After some reading I start to be convinced that the most likely source of the deep Granada earthquakes is a deep subduction zone under Spain.

By Mattias Larsson (not verified) on 05 May 2010 #permalink

I see fog cam is still working perfectly...

By Scott, sg (not verified) on 05 May 2010 #permalink

@ Peter,

I think I am with you all the way on this. What we are trying to explain is the genesis, not of magma, but the conditions needed that trigger its further ascent through the crust.

There are a couple of standard mechanisms for this, at least as I understood it with my layman's reading of the matter:

1. Crustal extension / fault propagation
here seismic movement "opens" up pathways for buoyant magma to ascend, facilitated also by the fact that the concomitant decrease in pressure will encourage the phase change from solid to liquid in existing shallower chambers of magma already cooled to a crystal mush (I think this is what we observed in the second phase of the eruption starting April 14)

2. top pressure (squeeze)
also possibly triggered by seismic activity - this was suggested in one paper on Chaiten I think.

3. buoyancy
apart from the general propensity of magma to rise anyway, a diapir (read large body of magma) will push up the crust above it leading to radial dikes and eventual/possible eruption at the surface.

and lastly
4. the case we have here where pulses or boluses of magma ascend from deeper in the mantle and stall at the mantle/crust boundary which, if conditions are right, trigger an intrusion event and possible eruption along lines similar to the crustal extension scenario. If I am not mistaken, this is the typical scenario in most monogenetic volcanic fields.

Right, looking at the pattern of seismic activity prior to the eruption of Eyjafjallajökull and the history of the region, I think we can rule out mechanisms 2 and 3, leaving the classical crustal extension model and the ascending boluses theory. Generally I would tend towards simple crustal extension and resulting ascent of magma from a pool of melt at the crust/mantle boundary. This could display a spike in activity as it would release a flood of pressure into the network of conduits and sills in the crust which would also propogate upwards in the fashion that we saw.

But I have a gut feeling the pattern of seismic activity would not be bell-shaped in this case but skewed with most activity at the onset and tapering off as the "flood" lost steam.

Which leaves your boluses theory. These have the advantage that they would display such a nice bell-shape as we saw. The only problem I have with the theory is that it implies that these boluses are arriving in a nice steady stream like beads on a string and also at a pretty rapid clip, particularly when you think the mantle is plastic anyway. I have problems visualizing that.

On the other hand if the boluses were arriving at spatially scattered locations under the crust, I would not expect the periodicity we observed in the individual swarms. Rather, I'd expect them to vary or even overlap which doesn't seem to have been the case. So, if we are going to go with the bolus theory, they must have arrived like a string of beads - and on a pretty rapidly moving string at that. Which raises a whole load of other questions.

By bruce stout (not verified) on 05 May 2010 #permalink

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