Eruption started at Eyjafjallajökull in Iceland

A shot from the Hekla webcam showing the glow from the eruption of Eyjafjallajökull that started March 20, 2010.

Quick note, but for those of you who have been following the seismicity at Eyjafjallajökull in Iceland, there is news from Iceland that an eruption has started. I will post more details as I can find them, but so far, evacuations have commenced near the volcano. It sounds like the eruption can be seen coming through the glacier on the volcano, but any real details of the style of volcanism are unknown. This is the first known eruption of Eyjafjallajökull since 1823.

UPDATE 9:40 PM EDT 3/20/2010: Here is some more news, but in Icelandic. It appears that at least 500-600 people living near the volcano will need to be evacuated.

UPDATE 9:45 PM EDT 3/20/2010: Here is information released warning pilots of the eruption. There are also second-hand reports of ash fall near the glacier on the volcano. Thanks to Damon Hynes for this info.

UPDATE 9:55 PM EDT 3/20/2010: More news, translated through Google. Ash has been reported and this article has a picture from the Hekla webcam showing the glow from the eruption.

UPDATE 11:25PM EDT 3/20/2010: Here is an update on the eruption from the BBC.

{Thank you to Jón FrÃmann for letting us now as it happened!}

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Saw it first on , of all places :-)

By damon hynes (not verified) on 20 Mar 2010 #permalink

Man standing at the river at Skógar says it seems that the eruption is in the direction of river. According to that it would be on Fimmvörðuháls not under the glacier.

Another eye witness in Thorsmork confirms that in radio now

No ash visible in 3km radar yet according to met.

According to national radio the eruption started at 23:32

Will post more later when more info is available

By Icelander (not verified) on 20 Mar 2010 #permalink

It finnaly happned! It may have took forever to get to this point but the wait is over finally. Does anyone know how big it is yet? Seems like there have not been many earthquakes so this is kinda a suprise.

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

Will be heading to Selfoss tomorrow (as close as I can get tomorrow!). Hopefully the eruption column will at least be visible.

Monday or Tuesday should bring a MUCH closer inspection, and I'm pretty pumped. Will let you guys know what's going on.

I've also emailed my trusty contact for some details but I don't know if he'll find time to reply, since he's basically heading this whole thing up. We'll see.

Fimmvörðuháls is the area between the glaciers Eyjafjallajökull and Mýrdalsjökull in southern Iceland.

Soceuls graph shows a sharp anomaly - the eruption spike?

Now we know why we had great big swings in the depth-vs-time plot.

Webcam feed is nearly saturated with viewers.

That msut be why the webcam sudenlly stoped working it crashes due to the sudden sure of people tried to veiw the viedo.

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

The power of the eruption appears to be increasing at the moment. I have also been seeing pules on my seismometer at this moment. They do not appear to be wind related.

Dang O still can not bleive it has erupted. was strating to wonder if all of this activity was for nothing.

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

Ican hardly wait to see what is going on as soon as it is morning. Being in CA, I get news pretty late. Anyway, I was able to inform the local news station that is an NBC affiliate that the eruption has started. They have been following it and now they can get the scoop on it. I know we will have news in the morning and maybe tonight at 11:00 our time. Three hours from now.

James, go for it!

Thanks Jon for your constant input from your equipment.

@Chance, it was what we were all watching for! I just hope it isn't going to be too major of an eruption for the people of Iceland and the UK. Depends on how much ash there is.

Now it is wait and see the extent. Many hours for me. :-(

Well the glow sure is birhgt on the webcam. Yeah we all wanted sometihg to happen and his shows that volcanic eruptions can be predicted.

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

There are small earthquakes appearing on IMO plot, it indicates that the fissure is expanding to the west in Eyjafjallajökull. That is bad, because it is moving to more glacier area then it currently is.


I have to take issue with you saying they can be 'predicted'. On the whole they cannot, and our discussion over in the thread never really came to "IT IT GOING TO ERUPT NOW!". Some of us thought it would, others thought it wouldn't, and no-one was sure of the timeline.

We could forecast it, arguably, but not predict it. Even Hekla can't be predicted on any kind of meaningful timescale, other than 'An eruption is likely within an hour' or something following the onset of seismicity in the volcano.

Not being an obnoxious idiot, just a personal bugbear when people claim we can 'predict volcanoes'. We really can't... ;)

There was no indication of EQ activity changing before breakthrough - nothing unusual at all.Rate was very low. Will be interesting to see if eruption migrates westward under the ice cap, since EQs have migrated 7km eastwards over past two weeks.

By Peter Cobbold (not verified) on 20 Mar 2010 #permalink

@Peter Cobbold, there was a ML1.6 earthquake at 23:04 UTC at depth of 0.0km, that was possible when the magma was breaking trough the crust.

I am still getting some odd activity on my geophone. It doesn't appear to be the wind.

The 4hz tremors at ESK seemed to have stopped at about the time of the eruption. This train of tremors had occurred without being accompanied by a burst of EQs. So this was different from previous two weeks.
Any clues there, Jon, James?

By Peter Cobbold (not verified) on 20 Mar 2010 #permalink

Lighting Strike were an issue when Katla erupted. The pictures should be interesting from quite a few places tonight.

@Jon, what do you mean by odd activity on your geophone? What I saw when I checked your site was evidence of the eruption. Well, I don't know how to read signals from geophones. I will check again to see what is going on. Maybe I can see what you mean.

High-frequency tremor is tectonic (i.e. rocks cracking, basically) so it'd make sense for them to have largely stopped - the rock aren't under the same stresses any more. Instead, magma movement is relatively free (presumably) and so more low-frequency tremor will become dominant.

Man, I really need to get to bed, but I don't see how I can possibly sleep with this going on (even though not much is really going to happen until morning!)...

@Diane, there are odd sized signals appearing. From 23:00 to 02:00 there is wind noise. But you can clearly see the odd sized signals after 03:00 line. They don't look like earthquake, but like something different.

The signals appears to indicate that the eruption is increasing in power.

Something is up at Chaiten (run Guillermo's link through Google Translate).

I did double take last night, about 8:30. I saw unusual lights on the distance webcam from tonw last night - appears to be a temporary camp of some sort. I've been watching Chaiten steam away for several weeks now and have mentioned it here from time to time.

Someone must be up there to take a closer look. I wrote to them last week and also to the USGS-SI monitoring group, asking why, if webcam images were showing clear signs of rather vigorous emissions and episodic eruption, was nothing mentioned. I got a handwaving reply, but they did include it in this weeks report.

I have asked Google for help in capturing and broadcasting eruption progress. They may or may not respond. I tried to make it clear that there is much more afoot than simple Eyjaf eruption.

The last time Katla erupted, so did Askja in the following year.

You follow? We have several volcanic centers primed at this point.

The last two times I asked Google for emergency help along with USGS/NASA, we got up-close satellite imaging of Katrina aftermath damage to help flood victims view property online, during martial law closure and more recently, got hefty Google images paired down and fed into software compatible forms for use in GPS and laptops, by emergency responders in Haiti.

We do good work.

@ James24 Then the tectonic activity that created the tremors was not detected as EQs since these were at very low rate all day. Maybe tremors resulted from EQs well below Mag1?

By Peter Cobbold (not verified) on 20 Mar 2010 #permalink

Huh?? What the hell are you talking about? Look at Socuel's rolling plot!

@Jon, thanks for letting me know what you are seeing. What I thought I saw from the Hekla geophone was the onset of the eruption and and some pretty major action.

I hope you can get some sleep tonight. It is 8:50pm where I am right now so it is time for ME to get some sleep, too.

We can only hope that UK Met Office wasn't snoozing when I sent them an emergency alert.

I really love that Hekla livecam. :) Guillermo #19, is Sernageomin writing that there has been some large earthquake activity at Chaiten? My spanish is poor ;) Sounds intresting in that case, meiby something will happen at the lava dome. Damm, the birds are starting to sing outside. :D It is soon morning here in Sweden.

By Mattias Larsson (not verified) on 20 Mar 2010 #permalink


I think it's a stretch to connect this with other centres, aside from Katla. There is a mechanical link of some sort between those two, but between Askja? Very unlikely. There are ALWAYS numerous systems in Iceland which are primed in some form, but if they erupt within a few months of each other I would wager it is purely coincidence.

Excluding Katla/Godabunga which ARE almost certainly connected somehow:

Hekla is 'due' to erupt, really, and could do at any point. Askja is actually showing some signs of activity but is almost certainly a while away from an eruption - within 20-30 years, perhaps. Krafla has been deflating since its last episode in the 70s and 80s but that is actually showing signs of reversal now, so perhaps that is very slowly building pressure, too. Grimsvotn is fast approaching pre-2004 pressure levels and so an eruption there within a year or two would not be unexpected (quite the opposite).

Just a head's up. If you type volcano on google there will be a live update section a quarter of the way down the page that supplies anything posted on the internet about the eruption. Tweets and news accounts.

Yup, UK Met replied - they must have gotten an alert from IMO. Good deal.

Ahh, a long fissure eruption! Explains the odd looking webcam image and large ash cloud.

Hope they're monitoring SO2 levels!

If the UK Met Office is tuned in here, you may want to think about issuing a little alert for respiratory distress in susceptible subpopulations particularly in Glasgow, Midlands and Greater London, because the OMI NO2 patterns over the UK (and many other places worldwide) has been looking really dicey lately. Typical Vernal Equinox ozone patterns.

Passerby 26#, I translated the Sernageomin link to swedish, and as I understand it they had detected the EQs from the Chaiten seismic network. Interestingly the origin of the earthquakes actually wasn´t from Chaiten but instead from the Melimoyu volcano! It is probably a nearby volcano. They also write that they are making an expedition right now to put up a seismic station at Melimoyu.

Melimoyu is a stratowolcano with a 8 km wide icecovered caldera. And guess what.... It hasn´t erupted since 200AD!

By Mattias Larsson (not verified) on 20 Mar 2010 #permalink

It does appear as though the fissure is lengthening or there is more than one. Odd graphic image

I wonder, how long will it continue to 'squeeze toothpaste' lava out? Bad karma if this were being fed via sill horizontal/lateral movement of lava from Katla.

Laki II.

Hey!!! A long fissure eruption east of the volcano! Is anyone going to buy me a beer?

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

@Passerby, jeepers I hope it's not going to be another Laki!! The last thing we need right now is to lose a growing season not to mention the direct impact on Iceland and the UK.

The Hekla webcam is showing a bright band all along the horizon. Where is the Hekla cam situated? I assume it is Hekla in which case we have fountaining over the icecap.. THAT does not sound good.

Let's all hope it stops soon!

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

YouTube video, not sure of date, but gives great perspective. Car travels right between Katla and Eyjafjallajökull. By my perspective, they travel awfully close to where this fissure presented?

Are those volcanic projectiles along side of the road or debris from a lahar?

That looks like a nice, typical Icelandic basaltic fissure eruption - for the moment. I am glad it did not turn out to be a large subglacial event; in any case the cataclysmic eruption and flank collapse scenario was a worst-case scenario, which means it's the worst that can happen but also the least likely.
Now let's hope this eruption will go on for some time and provide a nice show and a nice subject for study - hopefully some of you who have the chance will get there to see it. And, given the long duration of the previous eruption, it might become an interesting sequence of events. It's true, this resembles a bit those fissure eruptions (Eldgjà and Laki) linked to major central volcanoes like Katla and Grimsvötn, so we might see something in the caldera, some subsidence maybe or some ash emissions, as in 1783-1784 at Grimsvötn, during the Laki eruption.
Morgunblaðið has a new update with two very instructive aerial photos taken at daybreak: that fissure looks quite tiny at first sight.


Congratulations for predicting the type of euption! I will most certainly buy you an eBeer, are you on PayPal? (Provided you buy me one for getting time and location right. ;) )
Seriuosly: The weeks leading up to the eruption has been a fantastic learning experience, my thanks to EVERYONE who has contributed to my understanding and enjoyment of vulcanology! Now, let's hope this is the main eruption and that the consequences aren't too dire for us puny humans.

For reference and comparison when more images will be available:
The area of the eruption is to the right (east and north) of the Eyjafjöll crater.

(I post the link again for convenience since trawling through the original thread would be too tedious.)

Any further news about ash fall?
Is the fissure growing?

Found this picture of AFP(made in the first night of the eruption: Can´t beliueve that I witnessed the seismic activity now for weeks reading the comments on this blog and now Eyjafjallajölull erupted. And it did not erupt under the glacier so hopefully there are not those giants mud-avalanches....

By Thomas Wipf (not verified) on 21 Mar 2010 #permalink

Not much ash fall it seems at this moment, from the look at the images of the eruption - this is a classical Hawaiian-style basaltic eruption with lava fountains and fluid lava. Some news reports say that the fissure appears to be lengthening a bit but so far it's not affecting the glacier. I also understand that the orientation of the fissure is rather southwest-northeast, so that would be the main trend of the Mid-Atlantic Rift in southern Iceland.

Another video has been posted at the RUV website…

Thanks Boris! How long are the lava flows now? There is just one fissure correct?

Will the eruption oscillate? Another EQ swarm (magma bolus) due soon.....

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

just trying to find a good link for webcam but nothing is available ,can anyone help .

By paul jeannette (not verified) on 21 Mar 2010 #permalink

@ Bruce #45: Cheers! I'll buy you a beer in Mendig ;-)

Hmm... an eruption at Eyjafjallajökull is one of the nicest birthday presents so far ^_^

By Gijs de Reijke (not verified) on 21 Mar 2010 #permalink

May I express my gratitude to Socuel and Korf whose graphical presentations of IMO's EQ data has allowed us to follow the time course and three-dimensional pattern of hundreds of EQs over the past two weeks.
Their URLs are:…

Note that the eruption is somehere on the west extremity of the 7km long,linear, east-west EQ pattern that they revealed.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

@62, one line up: should read EAST extremity. (excuse: been awake most of the night)

By PeterCobbold (not verified) on 21 Mar 2010 #permalink

@peter Thanks Peter, you're welcome. These days were very interesting for me reading analysis you and other hinted guys made. So I tried to give as much as I could, given my void knowledge in this area.
@all : these has been a lot of requests regarding the graphs lately, I took note of them but a session crash got rid of them. Since they are note easy to find (my nick is spelled many different ways in the comments !), please, post comments here (…) if you have any request regarding the graphs (but please, keep on posting on scienceblogs for anything else).

Now I think everyone is happy : there IS an eruption, and nobody got hurt in the process. No jokulhaup so far. Let's hope things will stay this way.

Ah, a question : since we see some lava fountain, I thinks it is safe to say that the eruption occured at a place where the icecap is really thin (or there is no icecap at all). Does this mean the eruption is very close to Fimmvorduhals ?

On Google Earth/Maps the are some east/west lineaments/structures to be seen right in the middle between both glaciers. These look like the remains of fissures and it may be the place where we see the recent eruption. Would be intersting to have a detailes map about this area.

By Eva Sturm (not verified) on 21 Mar 2010 #permalink

Looking at Soucel's graph… and comparing it with the IMO map of Mýrdalsjökull in relation to the geographic location of the Fimmvörðuhálsi, where the eruption occurred (long & lat), the eruption seems to be near the Eastern end of Soucel's NE "bump" and not at its highest and largest point, which is located under the glacier.

The evolution of this eruption may contain many twists as - speculating on the appearance of Soucel's graph - there are two intrusive bodies, not one, and the main body has not yet reached the surface.

"Scientists had been monitoring the Eyjafjallajokull glacier, dormant since 1821, for signs of seismic activity but said there had been little warning of an eruption on Saturday.

"There was little increased seismic activity prior to the eruption," geophysicist Steinunn Jakobsdotter told local media, adding scientists had noted a few magnitude 2 tremors that were "not enough to tell us that an eruption was about to start."" -…

Yeah right...

By Gijs de Reijke (not verified) on 21 Mar 2010 #permalink

Personally I'd suspected something was up since the earthquake activity just died in the last day or so, but GPS showed continued inflation. Then Jon saw the low-frequency tremor beginning yesterday evening, and the alarm bells started ringing.

She's right in saying that the earthquakes didn't really give away the eruption, though.

Wow, that Reuters article is terrible. Absolutely terrible.

So many mentions of it producing 'smoke' - I especially enjoyed:

"...started to spew smoke and lava from several craters along a rift which is popular with hikers."

There is so much wrong with that sentence it's unreal. Smoke? Several craters along a rift popular with hikers? Uh, what?

I wish news agencies would make some attempt to report science, rather than grabbing hold of buzzwords like 'rift' and having no idea how to actually use them.

@ James #71: That might be true, but we've seen this coming for weeks. The eruption wasn't even a little bit of a surprise. Maybe there were almost no indications yesterday that is was to go within a few hours, but the activity prior to that would have made it more of a surprise when it wouldn't have blown any time soon.

@ James #72: true, very true. But at least in this case we can actually talk about 'red hot lava', unlike in many other news reports (not just by Reuters) when it comes to silicic eruptions.

By Gijs de Reijke (not verified) on 21 Mar 2010 #permalink

First, many happy returns on the day, Gijs! Shall we drink to your continued good health in an eBeer perhaps? @Steinunn JakobsdottÃr & James - no? There was a distinct change in the pattern reported on the IMO page last evening from c.18.00 at shallow depth in the same area remarked upon by several and then one at 0.0 km depth plus the tremors reported by Jón. Any word on the 1.1 km anomaly yet? Cheers!

In the absence of "fact" the Media are forced to resort to the ultimate resource - imagination. They are very lazy, aren't they? Couldn't even google and find you the way I did;-)

Now there is only question of time when Katla starts erupting with fierce power. I don´t think we will have to wait for long.

By Guðmundur (not verified) on 21 Mar 2010 #permalink

IMO had access to graphs posted here, same as the rest of us. It was crystal clear that something was afoot, with very, very large oscillating patterns in EQ depth the last few days, despite a relatively concentration of shakes.

All of us knew something serious was up when the depth readings maxed out soucels graph, and mean depth began rising. That last big, big spike and drop in EQ depth just before midnight and fissure breakthrough was like a signalman waiving a large, bright orange flag. Dike fracture and failure.

Peter's right. Continue to monitor Soucel's graph.

@ Henrik: Thanks ^_^ ! I guess for the time being any beer will do, eBeer or 'real' beer ;-) . Cheers! Maybe Vulkan Bräu @ Mendig in the future?

@ Guðmundur: I don't see any real signs that Katla is going to produce an eruption any time soon. An eruption from (the caldera of) Eyjafjallajökull seems more likely I think. But the earthquake activity so far has been located under the currently active fissure, so maybe/probably(?) the eruptions will be confined to the area that is active at this moment.

By Gijs de Reijke (not verified) on 21 Mar 2010 #permalink

I saw this news report in LA times and it is accurate except one sentence: "The most immediate threat was to livestock because of the caustic gases." It is not gases that threat (only if Katla erupts) it is the ash. The ash that comes from volcanos in that area is known to be extreemly rich in fluorid and harmful to livestock. It is also harmful to humans if it gets in to the drinking water. They are monitoring the cemicals in the drinking water now regarding this danger. The water to Vestmannaeyjar is the most sensitive side. They get their water from Markarfljóti a river close to Eyjafjallajökull. It was anonunced just now, in the radio, that the first sample of the water was save.…

Connection between Eyjafjallajökull and Katla

Initial reactions of earth scientists is that this is an unusual volcanic activity with regard to the earthquake that has been near the glacier. Indeed, only twice before Eyjafjallajökull has erupted in historic time. The years 1612 and 1821 to 1823. Scientists have identified a strong relationship is between volcanic activity in Eyjafjallajökull and Katla. Páll Einarsson, geophysicist says that all eruptions that have been in Eyjafjallajökull has been associated with Katla erupting. If Eyjafjallajökull starts is like Katla can not resist either.

Any guesses as to how high the lava fountains were this AM ? If the video is of a 1KM fissure then they must be hundreds of feet high.

By Dasnowskier (not verified) on 21 Mar 2010 #permalink

I've been following these threads for a couple weeks now, and I want to say I am amazed at the level of thought and deduction that went into this event. There are some great minds here that think both inside and outside the box. I feel bad for the people of Iceland, and hope this does not turn out to be another Laki event. Soucel and Korf, your graphs and plots were amazing and informative. I will continue to come here for all my info and to learn about eruptions. (I originally found this website when the Yellowstone swarm hit.) Hopefully I won't be reading anything about Mt Ranier or Mt Baker anytime soon though.

By James Hobbs (not verified) on 21 Mar 2010 #permalink

I hope Einar is tuned in here.

Play Soucels IMO EQ Map movie. Pay close attention to 2 areas of activity, one ENE of the eastern migrating centroid of EQ activity under Eyjaf (remember when I brought that up in the other thread?), the other at the southern end of Myrdals - watch for the burst of activity in the movie, and the connection directly back to the Eyjaf centroid.

Look at this map of the Eldgja-Katla Fissure System.…

See that southern most extension of the fissure system under Myrdals?

Now, this fissure system connection with Eyjaf was also active at the start of the 20th century, with a string of EQ activity and degassing.

Fissure/dike system expansion.

Lastly look up the USGS Earthquake map (
and click on the upper left panel, Past 8-30 day map.

In the last hour since I last looked, the map had also showed a surficial quake south of Iceland on the midatlantic ridge.

Look at the pattern of all of the major ridges, and look at the 'smiling' upwardly inflected curve pattern across major continental land masses.

We've got major flex stress of the crustal surface, as though there were a sudden pushing and spreading pressure within the earth, spreading the thin brittle surface layer.

This very large flexing pattern looks to have been present early in the 20th century, pushing at fissure systems on these ridges/faults, with energy release in large EQs at locked fault centers.

I suggest this is where we turn our attention for potential additional activity.

A question for any of the professionals here (Erik? Boris? Gris?). At present it's a classic fissure eruption of (presumably) basalt from a rift system on the flank. According to the GVP potted history, the last eruption (1821/3) was of relatively silicic ash from the central caldera. Would there be remnant silicic magma beneath the caldera-- and if the eruption extended towards the central vent, would it re-heat and reinvigorate this magma to produce a rather more explosive event?

since I can't go there at least till wednesday, can anybody, who is heading to Eyjafjallajökull give a short report, how far he got and what he saw?

Mike Don - it would depend on quite a few things: 1. how much interaction between the new basalt and older crystallized (or mostly crystallized) magma; 2. the thermal gradient between the two magma/crystal bodies; 3. the volatile content of both bodies and 4. the length of time they are in close proximity. It takes some time to melt and mobilize any melt produced from remelting/rejuvenating a crystal mush, so it would likely not be instaneous. It might not even really rejuvenate the mush into anything eruptible - instead the basalt might just become contaminated with melt or crystals from the remnant crystal/magma body from the previous events. It will be interesting to see if the current eruption coughs anything up from the last few eruptions.

EQ activity still continues ~5.7 km SSW of Básar (M1.0-1.9, depth 3.5~~4.5 km). This is some distance from the fissure eruption at Fimmvörðuhálsi (?). @Jon, what is your geophone/seismometer telling you about these quakes?

For the past two weeks we have watched the focus of EQ activity trend slowly eastwards to the eastern edge of the ice cap where the eruption is in progress. The original focus was due south of the Gigjokull glacier, a popular tourist site. So the migration path is roughly 7km long. My guess is that the fissure will extend westwards back under the ice cap, where the bulk of the magma has presumably accumulated. Eyjaf is thought not to have a conventional magam chamber.
I shall also be keeping a watch on Socuel's rolling graph of EQrate and depth. If further bursts of activity ('spikes')occur then we may need to consider if these do indeed represent new boluses of magma being added at depth. The potential for Eyjafoll sustaining an eruption for months, as history tell us it could,is obvious. The present rather small eruption should not deceive us. And that is without Katla being triggered.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink


You talked about a mantle plume.
maybe there is another way of feeding a mantle plume.
The mantle itself has a tidal motion of its own.
Like you mentioned before, The moon, the seas (tides) the sun etc.
They make up the (very slow) tidal motion.

If a plume is still attached to the upper belt of the mantle would it not make sense that the plume
would have the same tidal motion?

I can imagine that a M9+ earthquake creating a Tsunami (indonesia 2004)
or a Mount Sint Helens explosion, sends some vibrations right down to the mantle
and that it wil cause irregularity in the tidal motion of the (whole)? mantle.

could this be the cause of the oscillations?

A bit like we see now?

@peter527 "But how deep would this 'oscillating magam column' have to be not to appear on
Korfs or Socuels 3D plots?? Is that geologically possible?? And can magma move wihthout
revealing its motion as EQS or tremors?? It has to be moving down,stop then come up during the
relatively silent interval between spikes
@Bruce 512. Maybe a mantle plumelet oscillating"

Maybe YES.

There are no earthquakes in the mantle.
(only in the subduction zone, where the crust goes down into the mantle there are very
deep quakes. but this is the crust breaking up.

Allso the mid atlantic ridge lays very close to the mantle. if a plume is releasing fresh, hotter
maybe lighter material coming from the uppermantle, it could go up in the plume (becauce of
the tidel wave in the mantle?) without making EQ's (there's nothing to break)
only when that fresh magma bubble comes in the relatively shallow crust beneath Iceland we would see EQ's.

Just my 2 cents of thinking.

btw have you abandoned the "plume theory" ???

Peter #90, I agree with you. I also have a feeling that the fissure will start to extend towards the west.

Pascvaks #85, Yes the scientific level in the discussions of "watts up with that" is often painfully low. ;) Of course some people know what they talk about, but there is often alot of unscientific opinions and speculations.

By Mattias Larsson (not verified) on 21 Mar 2010 #permalink

The problem with volcanoes is that anything is possible. So we cannot categorically exclude that the small eruption that it is now may grow into something much bigger. Certainly, we all should be aware that the bigger, the less likely, and I would be more worried about myself slipping in the bathtub and breaking my skull when taking my shower tomorrow morning than about a massive and highly hazardous eruption at Eyjafjallajökull or something similar at Katla. This is all possible, but less likely than this eruption going on for some time very much as it is today and then fading out.
But maybe it's most instructive to look at some case histories. Silicic volcanoes surrounded by mafic (basaltic) eruptive vents are a common feature especially in rift settings, like Iceland and also the Ethiopian-Eritrean (northeast African) rifts. But some volcanoes do also change their magma chemistry and eruptive behavior in one eruption.
August 1991: Cerro Hudson volcano in Southern Chile produced a brief basaltic fissure eruption from its caldera rim, and a couple of days later, an andesitic Plinian eruption from a vent within the caldera.
1995-2009: a major rifting event in Ethiopia-Eritrea has so far produced a number of silicic and basaltic eruptive episodes, most of them quite small, which reminds me of the 1975-1985 Krafla rifting event. That one, too, started with sporadic and rather small eruptive episodes but gradually these episodes became more voluminous.
Certainly the strong seismic activity preceding this eruption seemed to indicate something much bigger than what it turned out to be. But this is also something that does happen at volcanoes. In 1883 the south flank of Mount Etna was shaken by a rather intense seismic crisis, and the following eruption was a minuscule burp, the volumetrically smallest eruption of this volcano that is documented in history. But two much larger eruptions followed, three and nine years later, respectively, which were not preceded by any significant seismic activity.
So, after all this, anything is possible, and I would not place any bet on a determined scenario rather than on another. Let's just hope this will remain a modest, though spectacular eruption and that it will last some time so that some of you who have the chance to go there will see it.

@Gijs Happy Birthday!! That must put you into a pretty select club, volcanologists who have had a volcano start erupting on their birthday! Doesn't get much better than that! The beer is definitely on me and yes we really must have a meet-up in the Eifel and get Heidi and Korf and all others in sparring distance to come down too.
@Henrik! Most happy to acknowledge your timing and location predictions! Definitely another beer!

- And while we're at it (buggar it, I'll just buy a keg!) Free beer for Jón, Soceul and Korf and James and Heidi for all the source information and graphics. And everyone else too. This was easily the most thought-provoking blog I have ever been involved with and I think I have learnt as much about volcanology in the last three weeks as I have in four years of casual reading and it has now got me very seriously hooked.

- but before I get too much into the party atmosphere, I was just thinking, this WSW ENE alignment worries me. I thought we were going to have a fissure along a WNW ESE trend which would have taken the eruption safely away from the Godabunga area. So if this fissure does extend we are kind of caught between the devil and the deep blue sea: to the west we have the icecap and possibly the remants of a silicic rich magma chamber. To the east we have a possible cryptodome that is rhyolitic (if I understood James correctly).

hmm. Might be time to get the washing in off the line.

James, have you managed to contact anyone from the university/IMO?

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

Boris or Erik, I have a nagging question in my mind that has not been completely answered (mostly so, I may have asked you, Boris, about it years ago or something like it). I want to know if there can be convection currents in magma ,especially if it is basaltic and not to silicic. I just wonder if there are temperature differences in the magma that could cause currents.

On another note, I have really appreciated all the input here and opportunity to watch something like this. I have not been involved in anything like this before and it has been very interesting to me, and I just want to thank everybody for all the contributions.

@Henrik, I do not get those earthquakes do to wind noise at the moment. The weather has been poor the past few days in that area.

The eruption appears to be increasing in strength once again. After a bit of dull this afternoon.

So I see it is so far erupting like Kieleua in Hawaii?

By Chance Metz (not verified) on 21 Mar 2010 #permalink

The IMO synopsis suggests the opposite of a westward progression. The first thing you notice is that the location and depth patterns are almost mirror images, and this is confirmed by quick examination of the lower panel.

Please do a simple Google search on the pdf document,

Download and read it, its just 2 pages. The authors suggest that are two magma chambers, one close to Godabunga.

Read about the two centers of activity, noting in particular the E-W trending fissure system west of the caldera.

Now the last time Eyjaf was active, Dec 1821- Jan 1823, it was followed within months by Katla, erupting in Jun 1823, from arcuate fissure complex in south part of caldera (that southmost segment of a very large fissure complex.

This is why I pointed to two specific locations as suspect for further fissure activity.

>The eruption appears to be increasing in strength once again. After a bit of dull this afternoon.

Supported by Socuel's rolling plot.

@Icelander: Radar is very close to 100% useless for detecting ash. You may see something briefly at the start of a large plume, but that's it. I haven't been keeping current with detection techniques for a number of years now, but when I last looked absolutely all claims that radar can detect the eruption column were made post-facto. As far as I know, no one can look at a radar trace and say "that's a volcano erupting" - it is always a case of knowing a volcano is erupting then looking at the radar and saying "hey, we can see something", and that is really of very little value.

By MadScientist (not verified) on 21 Mar 2010 #permalink

Thanks, Erik, guess we won't know for some time how this will develop. Funny thing, my first thought had been to mention the Cerro Hudson eruption as a precedent, but decided not to (very different setting, different volcano type)..and then Boris goes and mentions it! However, since it's been stated that Eyjafjallajokull apparently doesn't have a magma chamber in the 'conventional' sense, it may be thst there wouldn't be a significant amount of evolved silicic magma at shallow depths anyway.

Madscientist re post# 100

I can not agree totally with your statement. Mt. Redoubt in Alaska is a prime example where dopplar radar can provide utmost support.

In the very long active period there werer a few moderate ash clouds produced by Mt. Redoubt that were very well charted not only by preciptiation settings but also velocity setting at many levels of angle.

A few of these time there was a relatively low cloud shield that obscured developement and since seismographically, Redoubt would produce Lahars under roughly the same signature as an ash release, Radar was critical.

Radar imaging was also critical when it came to the direction these dangerous ash clouds took, for the forecast models woefully under performed at all heights.

Now as for Iceland, yeah, the radar system available to joe the viewer is useless at best.

Just my take on it.

>Radar is very close to 100% useless for detecting ash.

Somebody must have forgotten to let IMO know this valuable information.


>This working paper refers to the planned installation of a weather radar in East Iceland to improve detection of volcanic ash.

>A weather radar proves to be one of the most valuable and cost-effective tools for the meteorological agencies and aviation authorities in terms of preventing encounters of hazardous volcanic particles with aircrafts. To improve the monitoring of volcanic clouds in Iceland, IMO regards important to install radar in the eastern part of the country. In fact for full coverage three additional radars are needed to encompass the eastern, northern and south-eastern flight sectors over Iceland. However, the priority is to install a radar in the eastern part due to the fact that majority of active volcanoes are located in that region.

Microphysical characterization of microwave Radar reflectivity due to volcanic ash clouds. (2007) IEEE Transactions on Geoscience & Remote Sensing. 44(2): 313-327.


Ground-based microwave radar systems can have a valuable role in volcanic ash cloud monitoring as evidenced by available radar imagery. ...The radar backscattering from spherical-equivalent ash particles is simulated up to Ka-band and the accuracy of the Rayleigh scattering approximation is assessed by using an accurate ensemble particle scattering model. A classification scheme of ash average concentration and particle size is proposed and a sensitivity study of ash radar backscattering to model parameters is accomplished.

Radar location and operating frequencies used are important.

Ground-based, microwave weather radar installed for conventional weather prediction use would probably not be located optimally for ash cloud detection.

While we wait for developments, there are a few thoughts I'd like to share and have your response on:

1) "An eruption at Eyjafjöll is always followed by an eruption of Katla". This assumption is based on but two events - 1612 (E) + 12 Oct 1612 (K) and 19 Dec 1821 - 1 Jan 1823 (E) + 26 Jun 1823 - 23 Jul 1823. Is there a real connection or is it a case of coincidence that has been interpreted as correlation and then elevated to causation?

2) With a presumably basaltic Hawaiian eruption in progress, is the identification of Eyjafjöll as a stratovolcano correct? Looking at the profile of Eyjafjöll, it resembles a shield volcano more than it does a stratovolcano. The Global Volcanism Program site uses the term "Complex Volcano" in some instances to describe volcanoes that are capable of producing both basaltic and rhyolitic eruptions.

3) The last activity at Katla was in the Godabunga area and this eruption is not far from it. Could this be the beginnings of a new eruptive centre, a new volcano, located between Eyjafjöll and Katla? Soucel's graph seems to indicate not one, but two rising domes of magma separated by some 5 - 8 km, which *might* argue for such an interpretation?

I guess only time will tell.

By Chance Metz (not verified) on 21 Mar 2010 #permalink

I guess only time will tell.

By Chance Metz (not verified) on 21 Mar 2010 #permalink

@ Bruce #94: thanks ^_^ ! I think a trip to the Eifel would be fun. Maybe even more of the regular 'Eruption Bloggers' (meaning the ones that don't live in Germany or the Netherlands) can join us. Like Boris (he lives kinda close and he speaks the language :P ) or anyone else who's interested. My name below this comment is a linking to my facebook account, so maybe things can be worked out ;-) .

Your explanation on why it would probably become a fissure eruption made sense, btw :) .

@ all: very nice how information and thoughts about Eyjafjallajökull come together here. I'm wondering how activity will continue over the next few days/weeks/months/years. Personally I hope for something even more spectacular than what we've seen so far. Maybe even something explosive, although I don't wish any damage or hurt to anyone. It's a good thing Iceland hasn't got a big population.

Hope to see more pics and videos soon!

@Frankill 91 Oscillations. I'm been hooked on biological osscillations for years. I've no geological training whatseover, just general reading. Then a long comes a volcano in a country we love to visit, and it oscillates. Wow I just had to get on board. Then I get a distinct impression that ecperienced volcanologists have no answer to the type of oscillations we've seen, so there's no dropping the challenge. So here a summary:
The EQ-rate oscillates, but not - it turns out - with a daily rhythm, nor with a fixed period. That rules out to me a tidal swishing of anything including magma. The I focussed on the symmetry of each burst of EQs (a'spike')lasting a round 24-48 hours. They show a regular time course in EQ rate, some bell-shaped, others with rapid rise to a plateau rate with super-imposed spikelets of a few hours duration.Followed by a shut-off as rapid as the rise.There is no pronounced change in EQ depth within the spike from 1km to 8km deep. My notion now is that each spike represents a floating bolus of buoyant magma coalescing with the base of Eyjaf. One possibility is that the time course represent that bolus entering,passing through, and exiting a conduit such as might be associated with a magma chamber.But the 7km migration of the EQs, and double spikes would reuire a multiplicity of conduits which is not attractive.So currently I envisage the magma bolus exciting EQs in the overlying crust as it melts its way upwards below Eyjaf - assuming a roughly torpedo shape as it does so (that gives the fastup/plateau/fast-off time course).
I have to say that my attempts at using wild speculation to flush out a real geophysicist,volcanologist,or magma rheologist has signally failed. But I do hope they are thinking hard about the oscillations as there is, and on this I am convinced, useful information in them.
I'll reiterate what I've been saying for two weeks:the spikes look 'organised' in that their time-course is far from random. That to me implies an underlying mechanism of some simplicity.
Now that Eyjafyoll is erupting it will be interesting to watch Socuel's graph to see if spikes in EQ rate persist. If they do not I would argue that I am wrong and that the spikes probably originate superficially.If they persist, I hope the discussion will contunue until a geologically respectable mechanism is accepted.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

Anyone have an updated GPS information of any consequence?

This is a worry:
You have just come out of 24 hour's slumber,immediately gone to your PC and looked at Socuel's graph of EQrate and depth,
(here for newbies to the discussion:…

Now from that information only, tell me when the eruption started. Impossible isnt it?
Looks to me like the eruption has made not a snippet of difference to Eyjaf's EQs. That must be of concern.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

@Peter ha! signal failure was always my routine. Now I have a comrade in arms!

What you say about multiple conduits has got me thinking though.. why not? Maybe this is it. River channels of hot magma rising through fissured crust pooling in interim storage (a sill or like James put it, a sponge like zone of crystal mush) which, once it reaches a critical density rises to the surface.

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

@Passerby 98 IMO map for 19-21Mar shows no EQs east of eruption, which includes 24 hours post-eruption. Nice to see IMO's 3D pattern matching Korf's plot. Is there a (10km deep?) barrier there to eastward progression of EQ propagation?
The Páll Einarsson and BryndÃs Brandsdóttir paper gives the Katla and Godabunga magma chambers are at 0 to 3 or 4km depth. But no mention of one under Eyjaf: but have similar seismic analyses been conducted? Would we not have seen a focus of EQs under Eyjaf if one were present?
But east-west faulting between Eyjaf and Katla is interesting re coupling.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

The image quality is so poor, it's difficult to tell what is going on, but it looks like a second rift is ripping out. The TV station replaced the original link (which I have been watching for since it was introduced, anticipating this event (but at Katla or Hekla, not Eyjaf) with this one called 'extra' due to viewer link overload.

I just saw the camera jump! Unless there is someone playing with the feed near Hekla, that might mean there was a large EQ tremor nearby.

Peter, apparently there is no direct evidence of a magma chamber, although it was hypothesized in a couple of earlier papers I cited there.

But there is one, relatively close-by.

"The (magma) waves break both ways!"

Watch the camera! The rift is spreading rapidly!

Would someone be able to post a link up of the Hekla cam, as my wma is unable to play it in real-time.

I'm also wondering what people's thoughts are on wether venting of Eyjafjallajokull and possibly Katla over the next few days/weeks/months could have a further impact on the Stratospheric Warming Events we've seen the past two Winters.

By Snow_Joke (not verified) on 21 Mar 2010 #permalink

My initial take was lava flow from same fissure.

@ Bruce. Yes that would do the job, as long as each bolus escapes the sill and melts its way up with a 'defined' shape eg torpedo, exiting into a more compliant region (where EQs cease.) The bolus need simple shape to be capable of explaining the structured time-course of the spike. So I dont envisage the bolus generating EQs all the way to the surface: that would indeed terminate a spike suddenly (as seen) but we would I think have seen eruptions much earlier.
And could a bolus rise 8km in 24-48 hours?? - bit fast that for 'geology'?
Maybe this?: Each bolus melts its way through 'the sill' into the base of Korfs structure, generating EQs while moving through the sill but not once it has escaped. It compresses the overburden,inducing EQs, only when adding volume above the sill.

Pity though the eruption did not occur during a spike: that would have brought oscillations to the fore.

By Peter Cobbold (not verified) on 21 Mar 2010 #permalink

OK, I looked at this same camera image earlier today during the daylight hours. Looked same as always, despite different web page name ('extra', not hekla).

Tonight, it looked sorta like the one at the top of this blog page, posted by Erik.

Then, about 20 min ago, the long light colored arc near the top of the camera image faded, and I see a bright spot develop in the forefield.

Near the nearfield right hand side is the same tiny light spot, on the top of the kiosk clearly visible in every daylight image that wasn't occluded by bad weather.

I'm now confused about what we are seeing, since the bright arcs from last night are gone, replaced with a bright spot that pulsates, grows, shrinks and spits lava.

If Hekla is between the camera and Eyjaf *was* in the distance as shown in Eriks header for this blog, what is the source of the incandescence?

Why is it becoming oval?

Hekla?? No EQs to indicate it.

I suspect they have repositioned the camera, but those tiny 'equipment indicator' spots in the image nearfield, one bright one faint, are way too familiar from the old camera location nightly for months.

We got the light colored arc, now faint, back in the right spot in the background. Could be fog?

Just throwing out suggestions, but if its clear over there, and the camera's are capable of picking it up. It could be Aurora?

By Snow_Joke (not verified) on 21 Mar 2010 #permalink

3.4 just now under Vatnajökull 0.3km depth.

119: Maybe, but sorta doubtful, not much solar activity right now but we do have a weak sunspot that is growing in strength, beaming earthside. Locals on-board in SW Iceland will know.

Better SOHO/EIT 195 image from yesterday.

Second one.

01:45:31 64.520 -17.681 7.9 km 2.3 34.31 7.2 km ENE of Hamarinn

Looks like something is brewing.

Aye, something is up on Socuel's graph.

Light fuzzy background streak is consistent with position of lower arc on blog image, above.

Bright spot/arc midfield is temporarily gone again.


Weather moving through image; explains fading in and out.

For all that commented my entry (repeating it is not related to Iceland) the report says that the seismic stations located at Chaitén detected a serie of quakes near the Melimoyu volcano, several kilometers/miles south there. The statements of experts, the environment between the people and the sending of equipment make a sense that is not only a swarm, but it could be leading to an eruption.

The lights in Chaitén are probably cars or people that are living in the town (near 200)

By Guillermo (not verified) on 21 Mar 2010 #permalink

Eyjafjallajokull (AYA-feeyapla-yurkul)

I've enjoyed the collaboration shown over the last weeks on this thread. Thank you to all. I've stumbled across a site that I don't think was mentioned (or I missed it) which has some good overview information and current information on the eruption:

The Nordic Volcanological Center

Look at the hekla webcam!!!

BIG mushroom cloud... something explosive has just started there...

Magma/water interaction? Phreatic activity? Or the beginning p
of the plinian silicic event we all fear?

By Volcanophile (not verified) on 21 Mar 2010 #permalink

Indeed. We just had a large vulcanian explosion.

The ash column is no longer fed, but we can see the ash drifting away in the clouds.

Guesstimated altitude: at least 5km.

Watch out for things to come.....

By Volcanophile (not verified) on 21 Mar 2010 #permalink

Off to the races. I last posted before the eruption, and was busy that morning putting up a blog entry on LiveJournal summarising all that seemed "poised to pop," along with a grid map, about 13 hrs. before eruption. I add that Socuel's depth map leads close to the area of the eruption, but the eruption itself is not on his depth/coordinates map... the fissure is off to the east a bit.

Today I've been prepping 3-D imagery all day and was about to put it up, but getting slogged in the brain with lack of sleep. Big Caution in the meantime, stay on guard.

Points: 1. Periodicity is still working. Magma chambre is still sending force in spurts. So the first set of breakthroughs... which finally did erupt Sat. midnight (and almost did in that same location on the 13th if you look back) will renew, I think.

2. The magma is very hot, so is smoothing out its own pathway, reducing drag for the next burst up.

3. If there is "side-plumbing" to Katla, I believe it is below the 12km level... which is to say that while the magma/gas system was "capped" prior to Saturday night all the pressure that is locked into Katla was kept there despite the ups and downs of Eyjafjallajökull's periodicity. Now the "cap" is off Katla can rumble, but it is most likely to do so when pressure in the rising tube is at its lowest - in other words in the "retreat" ebb of the periodicity.
When Eyjaf is in its "rise" phase the sub-12km tube is full to bursting and highly-pressurised magma is fighting its way up into the relative resistance of the smaller/narrow upper seams and pipes ("choked" as my cohort geologist advises) where it has to turn a hard corner from vertical to horizontal. That, I believe, sort of pushes back against Katla and restrains expansion from the north during that point in the phase.

3. look at the GPS readings for Katla and the side flank of Eyjafjallajökull and you will see pronounced rising over the past 24 hours (unless I'm mistaken). The link is here (thanks Brendan) - - the data points are not that easy to distinguish but there seems to be strong upward movement.

4. I encourage you to re-watch Socuel's "tape" of the swarms over the past three weeks and you'll see that the repeated progression of "cracking open" followed two patterns: a - several exploratory fingers down and along the south flanks, even toward the sea (almost all the way down, under the "buttress" extension that extend from the south flank of Eyjaf) and b - as pointed out by Peter, James and others, a partial "ring" or "horseshoe" shape with its centre at the southwest, and the caldera is partially ringed by it. My friend believes this is a predictor of a caldera collapse, especially now that it is clear this is a basaltic eruption with sufficient heat to undercut the strata and smoothly open seams even more efficiently than the more gassy or steam-loaded former top-magma (why may have been partly rhyolitic) trying to initially work its way through, in the pre-eruptive days.

5. Lastly - there is, in the quiet phase of periodicity and possibility that there is now a reduction of "back pressure," a temptation to sit back and treat this as an amicable fireworks display. I see no reason to believe that the continued earthquakes don't signal further opportunistic attempts to expand available channels to become outlets of magma... it could come out in the Eyjaf spur closer to Highway 1, for instance.
And Katla, with her rising magma chambre, has yet to speak and is, I believe, somewhat stirred up. The opening (releasing pressure) to "the outside" by way of Eyjafjallajökull's first breakthrough is giving Katla periodic opportunities to stretch and push as well... and she may begin anytime.

Rúv reported that the ash cloud did reach 8 km high. There is a constant cloud coming from the eruption at the moment it seems. It appears on web cameras that point to Eyjafjallajökull.

There is a change happening in the eruption now. It might be turning more explosive then before.

@volcanophile.. thanks for the heads-up.

By bruce stout (not verified) on 22 Mar 2010 #permalink

Hmm... phreatomagmatic explosion?

By Gijs de Reijke (not verified) on 22 Mar 2010 #permalink

Right now, I'm watching it live on the Hekla webcam, which has been trained south (has a full screen option xD!)

"Continuous emission of vapour drifting NW(?), interresting. Must be a lot of melting going on. Hmm, have to pretend to work as well... Any hints?" ;)

I managed to get close enough to see the glow quite brightly, but a friend of mine managed to get close enough to easily see the fire fountains. I have to admit I'm jealous! The plan was to go back tonight but if things are changing that may not be an awesome idea. Keep us updated!

That looks about the same spot that he got to. We weren't so confident in our 4x4 so we didn't risk an unfamiliar track in the dark. Tonight should be different. Even volcanologists are getting stuck/breaking down in the area (much to their chagrin, I understand, especially when the media are involved!) so it's not an easy place to drive.

Looks like the Hekla webcam original position has indeed changed between yesterday morning and this morning, as I suspected. Tire tracks and missing kiosk. Minor sporadic image tremble noted. High wind or tremors.

@james: Thats why I am asking - I don't want to get stuck, I would just like to see it.
@passerby: We have heavy storm conditions here in south iceland, so the movement of the camera is quite likely due to wind.

@ Michael, Passerby. Prompted by your several posts I have been taking a wider view of the Eyjaf,Golda,Myrdals scene and have spent a couple of hours watching Socuel's moviemap=…
The horseshoe shape is pronounced, with Eyjaf at its western apex, curling around from Eyjaf southeastwards around Myrdals and northeastwards in the gap between Myrdals and Tindfjallajokull. Its an area much bigger than the 3D maps of Ejaf focus upon, being around 30km north- south and 40km E-W. Godaland is roughly at its centre.
I cannot detect any hint of the horseshoe arc extending to complete a circle around the eastern end of Myrdals.It has not reached the Eldga area.
I therefore suggest my focus on Eyjaf may have been far too narrow. Also note that no EQS at all have been recorded in 14 days from any site on its flanks west of its centre.
Eyjaf I'm beginning to think is a bit player on the periphery of this arc(see also comment 110)
So how does the oscillation ('spikes' in EQ activity) relate to Socuel's movie map:
1.The spikes in EQ rate correspond to a burst of EQs spreading widely around the horseshoe arc. Sometimes a frame will reveal a distinct arc of EQs 30km long.
2Between spikes when EQrate is low say 2-5 per hour the EQs are focussed on Eyjaf.
3 Speculation on mechanism. Each spike has a defined pattern: fast on/plateau (with spikelets)/fast off. Simple pattern means simple mechanism, so I'll continue to postulate that this time course follows a bolus of buoyant magma interacting with the system at depth. A deep bubble of magma. But I now envisage,because of the movie data,that
the bolus induces EQs over that horseshoe arc, approximately 50km long. centred roughly on Godaland.
These are all small EQs (M1 to 2 very few 3s) at depths 1-8km with no obvious pattern. That suggests to me that accumulated stresses are being relieved but not by magma intrusion as the arc is too large and no foci are apparent.
I suggest that the horseshoe arc reflects boluses of magma floating up, conceivably as bubbles from the deep mantle plume,and colliding with the underside of the crust underneath the EyGoMa area, roughly centred on Godaland.
Each bolus induces EQs with a time course that reflects is shape- maybe spherical or torpedo shaped, but a shape as regular as the spike's time course. Buoyant bubbles tend to assume a regular shape. The increase in pressure on the underside of crust releases strain over wide area. But why in an arc?:
I envisage magma bubbles accumulating in an inverted funnel in the underside of the crust at the mantle boundary with its apex under Godaland. The funnel walls are circular, and at present are detected as the horseshoe arc of EQs.
An accumulation of buoyant pressure acting radially on the walls of a funnel might account for the outward pressure that seem to be forcing the THEY and SOHO GPS stations apart, and the THEY station to south. James hinted at oscillations in some GPS data - do they correspond to the spikes?
My overall picture of the oscillations is now much bigger than before. Eyjaf is the sideshow I fear. On this model the spikes will continue as further magam boluses continue to rise from the mantle depths. One is overdue now.
On this hypothesis the reason why Eyjaf appears to be coupled to Katla is because it is the sideshow, a weak point that erupts before the main action under Katla and Goldbunga, whose two magma chambers could well be filled from those putative rising boluses of magma from the depths.
Is there a rheologist out there who can put a ballpark figure on the diameter of a rising sphere of magma that takes 24 to 48 hours to complete a collision with underside of the crust.

By Peter Cobbold (not verified) on 22 Mar 2010 #permalink

I see the THEY GPS station continues to show inflation. Apparently they got up to the ridge last Friday and placed two GPS devices on the ridge, one to the north and one to the south of the current fissure. This was total blind luck, but they are getting perfect readings! I believe they are heading up there today to collect the data, if the weather is ok. It'll be interesting to see what that shows.

I also keep on seeing occasional flashes on the Hekla cam. I thought they were artificial at first, but I'm fairly sure i've just seen a CG Discharge in the past 5 minutes.
I'm assuming the cloud that's been hanging over the Cam all day is infact the Ash-Cloud? Which would explain the electrical discharge I think I'm seeing.

By Snow_Joke (not verified) on 22 Mar 2010 #permalink

We certainly saw no discharges last night, but with the heightened ash activity it could be beginning, I guess. Will report back on what I see after tonight (hopefully).

Beautifull lightshow on the Hekla webcam right now

Continuing on from 143.Bouncing Bolus. A large spherical bolus of magma rising up from the depths of the mantle impacting the underside of the crust should show evidence of rebound. Rebound could underlie the spike on the 18th: is it an attenuated hit by same bolus from 16th? And maybe there are two further slight hints of highly attenuated signal on 20, 21 (look at Socuel's smoothed curve) Overall the picture I get is of a damped oscillation lasting 6 days:all induced by one bolus of rising magma.
The rebound analysis can be pushed further. Look at the time-course of the spike on 16th. The rapid rise to 60EQs per hour would represent the upper hemisphere of the bolus hitting the crust and inducing an expansive strain that puts the Eyjaf-God-Myrdal arc under tension. EQs are generated as tension fractures the weak points scattered over the arc. The upward pressure is sustained during the plateau as the whole bolus comes to a brief halt.Then as the bolus rebounds that upward pressure is released and we get a further big spikelet of EQs on the falling phase of the spike. During most of 17th the bolus is in reduced contact with the crust until its buoyancy reasserts vertical motion. So the following spike on 18th is of lower EQ activity but of remarkably similar time-course, even having the leading-edge and trailing-edge spikelets of tension and relaxation. Same shape=same time-course, butless imparted energy
Guesstimate: If the magma bolus were say 2km diameter and rising at 100metres per hour then the time taken for the top half of the sphere to fully impact woud be 10 hours: =the rising phase of EQs from baseline rates. Then a further 10 hours for the trailing hemisphere to catch up(the plateau. magma now a concave cap?) and another 20 hours for the rebound.
For the reasons given here and in 143 I have come round to the views of Michael, that there is a potential catastrophy here. The movie map shows that the spike on 16th-18th induced EQs around the southern arc from Eyjaf. The northern arc EQs were more abundant in the early spikes. It seems to me that the land-mass north of Goda might now be resisting creep induced by these deep magma boluses. The amazingly rapid separation of GPS stations THEY and SOHO suggests to me that the southern wall of the Eyjfa-Gold-Myrdals struture, supported to the south by air, might be shifting as a result of sustained magma bolus pressure.The magma's buoyancy will provide steady uplift after the bouncing has ceased.
If streams of large magma boluses appear from the depths (under influence of mantle plume?) every 200 hundred years they provide a means of synchronising Eyjaf and Katla and of recharging a putative magma reservoir/layer at the mantle crust boundary deep under the volcanos' magma chambers maybe 10-15km above them.
I await the next spike with some concern.

@ James. Can you get me info on those GPS oscillations? My email is; pcobbold(curlyat)fireflyuk(dot)net

By Peter Cobbold (not verified) on 22 Mar 2010 #permalink

@Chris : thanks ! Do I see two smoke sources on the video, or is it just my imagination (or did I miss something ??) ?

Peter Cobold,
Based on your most fascinating "Bolus" theory, you conclude with the remark "I await the mext spike with some concern".

Please specify "concern'!

Do you expect the current fissure to grow or do you think the current eruption will grow onto a much bigger scale event over a much bigger area?

Just curious what's really going on in your mind!

By R. de Haan (not verified) on 22 Mar 2010 #permalink


you mean the Hekla webcam?

@Peter Cobold: Just think about necessary viscosity of the circumjacent (rock) material, if a bubble of 4 cubic kilomter (!!) shall rise 100 m per hour! The lava lamp model is nice, but there we have 2 liquids with similiar (low) viscosities. I would rather stick with some sort of sponge modelling, where the partially molten mantle material is flowing along cracks and faults towards the surface, erupting in a fissure we now see.

@R de Haan. I think the fissure eruption may be almost irrelevant because I sense much bigger forces at play. The two main reasons are:
1 The long arc participating in each EQ spike (I only just spotted that- hence lengthy posts above!)
2 the huge migration apart of the THEY and SOHO GPS stations to the south of Eyjaf and Myrdals(6cm in March)
If giant boluses of deep magma are the common cause of both these processes then the next boluses may provide the necessary impetus to cause further dilation and maybe lead to sector collapse (rupture of the caldera wall) in the arc southeast of the Eyjaf activity. I sincerely hope not. There is a volcano under the Myrdals ice-cap close to the origin of the Solheimajokull glacier......
(marked as 'active subglacial volcano' on Fig 8.1 in 'Geology of Iceland' Thorleifur Einarsson).

By Peter Cobbold (not verified) on 22 Mar 2010 #permalink

@Peter Cobbold - I hope I'm neither alarming nor "unalarming" anyone. My intention is to not leave possibilities behind which may signal workings that have a grander design (such as the off shore deposits of debris might suggest) or the possibility of a slow uncorking of Katla, or a late-arriving caldera collapse under Eyjafjallajökull's glacier.

I did notice, in my re-visits to Socuel's time lapse of the pre-eruption swarms, that if I put my cursor over the point of actual eruption, and then observed the number of times magma "visited" that area ("prepping" it, as it were, for eventual breaking-open) and compared that to equal or greater number of magma visits to adjacent areas under Eyjafjallajökull's south face... that there were actually *greater* intrusions at mid-phase into the southeast face of the mountain (almost down to highway 1) than there were north-eastward into the eventual point of eruption.

There are "buttresses" sticking out from Eyjaf there. The quake history reveals that there probably is a pipe/fissure system under them pointing seaward. I've asked several times if a geologist familiar with the strata of Eyjafjallajökull could *please* point to an accessible paper or detailed geologic map which shows the underlying geologic composition of those slopes.

It seems to me that since this mountain is the "buffer" between Katla and the ocean, and it is starting to break apart (just a little at the eruption point at the moment - but not relieving enough pressure, obviously, to stop the adjoining ridge or Katla from continuing to deform upward)... so we should look at Eyjaf's structure... to see where it is weak.

Just to chime in here, most models of melt moving through the mantle and crust I am familiar with tends to lean towards percolating flow through cracks or along grain boundaries rather than as a "blob". There is a lot of use of terms like "plumes" or "chambers" or "pools", but really, there is little strong seismic evidence for vast seas of magma. I would imagine melt being produced at the base of the crust under Iceland thanks to the ocean-ridge spreading or the hotspot would be percolating up through the crust and coalescing into a dike as it nears the upper crust ... but that is just the model I prefer.

You're getting caught up in trying to understand finestructure that really can't be visualized well by the extant data sources, which provide *reactive* not causal, map of activity.

Back to the Basics.

Download this document:
Introduction to Geology and geodynamics of Iceland

Our analytical perspective now must pull back to an Iceland-wide perspective.

Pay particular attention to the layered, ridge-spreading history Fig 2, and Fig 3 Volcano-tectonic map of Iceland.

When looking at Fig 3, mentally sync the elongated shapes of our two target volcanoes under action of the plate boundary transform fault, with their relative to location to the accumulating layers of crust in Fig 2 - make sure you mentally TILT the superimposed inset Booshelf faulting (SISZ) graphic in Fig 3 (look for points 6, 7 and 8 that define Myrdals and Eyjaf volcanic masses).

Next, look at the placement of the small red circles major recent seismic activity. Lastly, look at the large fissures (primarily the 'layer line' that underlines the lettering of ERZ -Eastern Rift Zone. this is point 8, 0 MYA on Figure 3.

That line leads precisely to Godaland and it's very likely the mainline source of magma movement to our volcanic center of interest.

Now think about the flow of land mass moving in a rotating couple about our volcanic center above and below that fault that butts up against Eyjaf.

Don'be thinkin' plume here...that action center lies further up the landmass, an imaginary horizontal line connection of those volcanic centers in the middle of the country.

The Eastern Rift Zone is a residual flow passing under Katla and Eyjaf, terminating in the offshore volcanic center.

Myrdals glacier has lost 20% of historical ice mass, Eyjaf nearly 12 percent, since the last major cold period (LIA). That means warmer water and surface temperatures and either less total precipitation or less frozen precip and more rain on these glaciers and the surrounding valleys.

What you have is force-couple with dynamic compression with its action center right between Eyjaf and Katla -the short heavy concentration line of of red dots is the obvious, raised feature of an active historic stress fractured intrusion zone that intersects with the radial fissures of Katla's flank. The displaced EQ activity is magma moving to the surface along fractures at the edge of the glacier.

These are the BIG forces that must be considered in any mental model of volcanic activity.

The eruption of the Iki-Crater in Hawaii was calculated rather precisely based on the assumption, that the rise of the magma along cracks and faults was indicated by the obersved rise of the hypocenter of the eartquakes. The observed movment was 600 m per day, starting at a depth of 55 km. 92 days later, at the 14th Nov, a fissure eruption started.

Right, I understand!
That would be a catastrophic event with huge repercussions in terms big time ice melt, mud lahars and a massive expulsion of ejecta.
A caldera collapse would would create an immediate explosive event
that would send massive amounts of ash and SO2 above Stratosphere level (that would not be to high at this Northern latitude.

When you think out loud what scale are we talking about?

Where do I get Fig 8.1 in 'Geology of Iceland' Thorleifur Einarsson
I downloaded several PDF files based on a Google search but did not find it yet. Any suggestions?, Any insight is highly appreciated.

Thanks in advance.

By R. de Haan (not verified) on 22 Mar 2010 #permalink

In reviewing the composite GPS charts, I still remain convinced that the eastern portion of the SISZ is very much in play now.

Reviewing the movements suggests quite the vertical anomaly at the ISAK site. (as an aside the graph certainly shows the seismic activity in 2008) Would the snow-bombs being generated by Eyjaf's fountain fissure be enough to trigger the tension on this portion of the zone?

Erik posted as I was crafting my response, which was pointed at Peter and Michael.

Using Fig 3 in the pdf cited above, look at the IMO general shake map. Look at the concentration node in the far north, off shore. Look at the node on the mid-ERZ. Look at the concentration node at the Reykjanes Peninsula and further south, offshore. And of course, look at the concentration at our volcanic center and the teleconnection with the SISZ.

Compare the match between figures. This isn't about casual correlation. This is about understanding WHY now, why Eyjaf and not Katla - yet.

Peter has it correctly. Eyjaf is smaller, its volcanic landmass is being rammed into Katla's and its under heavy compressive forces. It's brittle surface fractures will fail first because of one simple fact.

Difference in mass and tapering underlying crust thickeness. See cartoon, Fig 5.

Put your hands together, palms facing down, finger tip to finger tip. Push. What happens?

Yeah, right at the E-W trending sill, where magma has percolated and pushed up in the past.

Eva, But there's 10-15 km thickness of rock above the 2km bolus to absorbe the impact. Maybe a smaller bolus would more realistic,moving slower?- its pure guesswork.
The GPS data are a big worry and the huge excursion between THEY and SOHO are not explained as far as I can see by magma intrusion.

By Peter Cobbold (not verified) on 22 Mar 2010 #permalink

@Peter Cobbold - one further thought, stimulated by your thoughtful musings and modeling of possibilities.

While this IS a volcano with a history of jönkulhaup eruptions (a defined strato-volcano under a glacial lid like Katla) it has not historically shared the same magma signature as Katla, being more explosive-gassy-rhyolite than andaesite-basaltic. While the present eruption location on the ridge between itself and Katla was not preceded by any "exploratory" quakes from the Katla side... all expanding and cracking open of seams came from the Eyjafjallajökull side... yet this has not been (by temperature and behaviour) a rhyolitic eruption, so far anyway. Is there an explanation for this anomaly?

Two further questions.

1. Despite the volcano's "familiarity" with and opening up of pre-existing fissures and pipes from the 1821, 1612 and 550 eruptions, is it uncommon for a volcanic mountain to create entirely new routes providing channels for magma release... channels that are perhaps more efficient than those existing from the past?

2. Does the shape of Eyjafjallajökull in any way resemble a ring dyke as much as a volcano? The ring-shaped surround and the fan-shaped distribution of quakes as each new "blob" of magma comes up, hits the 12 km. level and propagates (sort of like a cross-section of an artichoke) was an interesting resemblance, but perhaps I'm all wrong. Does anyone else see it... or see any usefulness in ring dykes as *part* of the hypothetical model, particularly their vertical faulting?

See - for some thinking on this subject, also papers by Brian O'Driscoll.

RE: Peter Cobbold's "bouncing blobs"

"Bouncing" implies a good bit of elasticity (as in, recoverable energy stored in deformation.) I'm not all that conversant with the mechanical properties of magma, but generally incompressible fluids and plastics aren't big on elasticity.

Put another way, I wouldn't expect much more "bounce" than you'd get from an blob of olive oil rising to the top of a bottle of vinegar.

By D. C. Sessions (not verified) on 22 Mar 2010 #permalink

Rivalta, E., and P. Segall (2008), Magma compressibility and the missing source for some dike intrusions, Geophys. Res. Lett., 35, L04306, doi:10.1029/2007GL032521.

>Dike intrusions are often accompanied by localized deflation, interpreted as depressurizing magma chambers feeding the dike. In some cases the inferred volume decrease is a factor of 4-5 less than the volume increase of the dike. Here we explore whether this discrepancy can be explained by compressibility of the magma combined with the fact that cracks are much more compliant than equi-dimensional magma chambers.

Large changes in magma compressibility is due to gas exsolution. The presence of gas bubbles and crystals, a function of mixture melt temperature and cooling rate, largely determines magma rheology (a Bingham model fluid).

It can be compressible and display plastic deformation behavior.

Magma blobs and oscillations.
I know I'm getting boring but I must reiterate that those EQspikes have structure in their time-course, which implies a simple mechanism causes them. It is highly unlikely that the EQ pattern results from forces such as stick/slip or magma feeding through cracks- volcanos are just not that regular.
I am now certain - because no volcanologist/geologist/anyone has pulled me up with evidence to the contrary in publications(or worse a textbook)- that Eyaf's EQ oscillations are highly unusual, possibly unique.
It follows that we need to consider what simple mechanism can generate EQs with a regular time signature over an arc-shaped region 20-30km across.

@DC Sessions. You win - I agree bounce is rather improbable, I got carried away with the damped appearance. So each spike is generated by a separate bolus of rising magma. The on/plateau/off mechanism of compression and relaxation to explain the spikelets is still valid,I think.

So what other explanations of the spikes have you got?
I'm pretty much out of new ideas.
But there's something really interesting going on with those spikes -maybe fundamental - I can feel it.

@Socuel. If Eyjaf does not give us more spikes we soon wont have any left on your rolling plot. Could you put up a static graph from day1 to the eruption? Please. Merci mille fois. Diolchnfawr.

By Peter Cobbold (not verified) on 22 Mar 2010 #permalink

>So what other explanations of the spikes have you got?

The obvious one: successive material (rock) failure. Look at Socuel graph of smoothed depth.

What is the trend from March 17th on?

How many times have we seen these exceptional spikes (off-scale deflections) in depth?

How many events have we had?
2. Primary fissure breakthroughs, second with small explosion/plume. Last large 'hump' on the graph = magma emission volume jump.

Q: what happens when the general plot trend hits very shallow depths?

Yes, very fundamental. Copy the plot to a simple graphics package, find and trace the baseline on the declining phase since March 17.

Two days, more or less.

I'm going to go radical here. I just had an hour and a half conversation with a volcanologist colleague who's been reflecting on my hunches for the past three weeks... I, oh bear of little brain. Here's what I feel, restated slightly from prior posts and my own blog:

1. Eyjafjallajökull is no longer a stratovolcano. It's days as such are over. It has been "co-opted" into Katla's plumbing and will be andaesitic-basaltic in the future.

2. What's scary is that this is new... it has been rhyolitic in the past. So (except for its north and northeast flanks, where it abuts the basaltic strata of Katla) it is basically a quasi-porous, fissured, compressed-layered jumble of past rhyolitic eruptions built up over almost half a million years. It's not strong... as passerby says, it's weak and it's small and it's "flaky." And very meltable.

3. Due to torsion-forces recently felt in the region, exerted from the Reykjanes ridge outward and perhaps reflecting global plate adjustments of the past several months, some kind of sub-20km breakthrough has occurred whereby Katla's magma source (basaltic) found its way into Eyjaf's plumbing. Like a groundhog churning its way through earth that had been pre-burrowed by moles, the white hot 1100° basaltic magma recently began exploiting all the multiple weaknesses in Eyjafjallajökull's structure.

Look at the Soceul's time-lapse for clues. It was stopped from going northward by the basaltic underpinnings of Katla's formation. So it has primarily (at each "push" phase of the periodicity) gone south and east. Everywhere after it cut its channels it now sits and cooks... melting the rhyolite around it... turning it into mush. Eyjafjallajökull may look solid, but it is slowly melting inside as the channels fill with white hot magma and the channels open and deconstruct the mountain from within.

4. On one of my maps I indicated a southern spur where the magma three times extended a "tongue" (almost down to Rte. 1) on the south face. It's weakening the geologic structure of the mountain there. Meanwhile, like someone blowing up a balloon, Katla's main magma source continues to increase pressure inside itself in answer to the same torsional pressures from without... pressures passed along, I'm pretty sure, through the channels of the plumbing now connected to Eyjafjallajökull. Toothpaste in a tube.

5. I'm concerned that the south face of Eyjaf will burst at some point in the "push" phase (hopefully Peter or someone else will pinpoint the mechanism of the oscillations). If that break-out is low to the mountain face, I suspect (because no one has told me otherwise) that the mountain above it will collapse and "slide out" on the hot magma that will drain the inside of the mountain out... like a patient in the advanced stages of Ebola.

While some are anxiously watching for an eruption of Katla, it is Katla that has found itself a new "drain" for its own underlying pressure. No longer does it have to push against its own surrounding ridges of tough basalt... it has weak little Eyjafjallajökull to blow its magma pressure out through. At the moment, I think, it is just getting all its ducks in a row... but meanwhile, more and more of Eyjaf's innards are being compromised.

I think we are possibly seeing a complete changeover of volcanic pattern for southeast Iceland here. After this, whatever "hole" remains where Eyjaf once was, will be the new caldera outlet for the magma source which once fed Katla, and will become a mountain of layered basalt/andaesite instead of whatever it has been until today.

BTW, we must have just had or will have momentarily another 'event', as indicated by Jon's geophones and Socuels graph.

Gah! What a comparison: 'viral' magma tunneling wall failure and a toxic patient hemorrhaging out.


That must be a disapointment trying to flush out some pro's and then me, sticking my nose in to it!

i miserably failed to explain something i thought, would maybe give you a clue in the direction
you where looking fore.
No much sleep , the language, and pressing all my knowledge into barely 10 sentences
didn't mix well.

you're knowledge surpasses mine 10x with Volcano's
But still, i was thingking in the same line as you. (but lacking the knowledge & fine-tuning)

So, a second attempt and i want bother you again.
if you already know or read this article, i appologise

A least it is interesting and easy stuff to read, if not fore you maybe for a passerby.

There is a brief note about a puls also.
(in the first chapter, last sentence).

about the "buoyant plume"

notice the 2 last senteces. (and you talk about a giant one)

you would need a helping hand from the first article or the mantle itself.

I know it is far out of the box thinking with a 0.001% of happining.
but thats not my point. it is about complex interactions.

@Michael Cerulli Billingsley, at the moment there are no observation that support this idea. The events you speak about would be quite explosive.

Far as I can tell this is the lighter material inside Eyjafjallajökull and it most likely comes from a 5km magma chamber that appears to be in Eyjafjallajökull. There is however more explosive magma on the rise at this moment, and it is about to break it's crust blockade with earthquakes I guess. That is at least the clues show that have been appearing in past few days.

@ Fascinating thoughts everyone!

@Peter, does the periodicity in the uplift shown on the godaland GPS plot (bottom chart) correspond with your theory?
i.e. it is not the liquid magma at depth that is bouncing but the elastic crust above it? (a similar pattern can be seen at THEY and SOHO, just not as strongly expressed.)

@Passerby, are you predicting the main eruptive event to occur in two days?

@Micheal, interesting theory. Certainly intrusion of hot basalt into the eyjafjallajökull massif is a great cooking experiment and I wonder how much rhyolite is currently getting melted from the addition of this heat. Question of how much basalt has reached shallow levels and where it is. If we take the sponge model and assume a high volume of fresh basalt things could certainly get very interesting in the coming months. If the basalt is in isolated dikes or long thin fissures it is more likely to cool off before any large body of rhyolite melt forms. If on the other hand, the dikes are numerous and close to each other, they may store enough heat to indeed create a rhyolite magma chamber at shallow level, also a question I guess of how much residual heat is anyway stored under Eyja from past activity. This remains very fascinating. I don't think anyone can really say how it is going to pan out, i.e. there is still a chance of an explosive eruption, bearing in mind Boris's inverse probabilities principle

@Passerby, you remain the most enigmatic poster here with the most intriguing ideas - are you predicting a major event in 2 days or what exactly were you meaning in post 169?

@Erik + Eva, I have to laugh. What came to me as an ephiphany two days ago when Peter talked about multiple conduits I now learn is a standard model. (ein blindes Huhn findet auch mal ein Korn!) I am loving this learning experience! Thanks again for the opportunity!

By bruce stout (not verified) on 22 Mar 2010 #permalink

@Passerby 168
">So what other explanations of the spikes have you got?

The obvious one: successive material (rock) failure."

hmm. not entirely convinced by this. Wouldn't this then follow a pattern like normal tectonic activity? Either something like a main shock followed by aftershocks (like Omori's law but on a smaller scale) or like any other EQ swarm we have seen (rather chaotic). As Peter says, this pattern is highly organized. Can this really be explained by successive material failure?

PS I see I repeated myself above, sorry!

By bruce stout (not verified) on 22 Mar 2010 #permalink

Cool stuff James! Was that lava fountaining constant? I take it we are looking up from the Krossa valley at the cinder cones, is that right? Must have been an exciting trip!! Most envious!

By bruce stout (not verified) on 23 Mar 2010 #permalink

Thanks for the photos James. Sorry to ask you once more, how far do you get and which roads are closed? I guess you used road nr. 261?

Yeah, lava fountaining was more or less constant. It wavered in height a little due to pressure changes but it wasn't Strombolian activity - there was always something there. There looked to be three or four discrete high fountains as of about 9pm.

I believe there was a team of volcanologists camping up there last night, to collect GPS data. I do not envy them in that weather!

I think it was the Krossa valley, yes. You can head up a small mountain, along a pretty awful gravel track, which gets you a much better view.

@frankill 172. (I think the plume 'pulses' referred to are on time scale of millions of years.) There seems to be agreement that the plume - whatver its shape and size-influences Iceland, even as far as explaining its existence. The discussion seems to centre on whether material from the plume contributes to Iceland's varied petrology or whether the presence of the plume merely influences more superficial magma incorporation into Iceland's crust. Things like He isotope ratios, water content dominate the discussion. This question does not appear to been resolved, but clearly if large areas of Iceland do prove to be made of plume-derived rock, then there has to be a route for its joining the crust, relatively uncontaminated by upper mantle material. Maybe that's what the spikes represent; a fundamental process.
All we need now is sample of a blob for He3/4 analysis and water content!
Its those 0.001% chances in science that are often ridiculed but so often open up real new insights. There's nothing worse in science than a consensus: that's a dead end.
I wonder if the Yellowstone EQ swarms in 2009 and 2010 show any periodicity like Eyjaf. Mt 28kbps dial-up connection hampers surfing. Could you go there, find out?

By Peter Cobbold (not verified) on 23 Mar 2010 #permalink


The 2010 swarm at first glance does not fit the bill.

The 2009 comes a bit closer (sort of a regular returning spike in the begining followed up by some irregular spikes towards the end. But the building up to the spike and the shut-of look to smooth. (only 31dec does just that)

I was hoping to find more graphs with magnitude,depth,and time.

This is a site where i follow up EQ's in Y.S. now and then.
No problem finding something for the last 2 weeks,
but could not find graphs before 2009

I have found some graphs but they are pritty basic.

Let me know if you want more detail. I will then poke arround some more or try somewhere else.

I mail jou the graphs in a few minutes.

WORK MAPS - I've made up some maps based upon a stitched panorama from GoggleEarth of the affected terrain, keeping it as high resolution as possible and enhancing contrast. I've also added latitude/longitude in the format used by Iceland Meteo to make correlating new quakes easier.

Open use. There's a low rez version showing the location of the first fissure eruption, and two higher resolution (one full resolution for projection, and adding data). For the highest resolution be sure to click through to the gallery version.

@passerby, bruce stout, jón - I hope my colourful analogies don't cloud the hypothesis (the legacy of a lifetime of teaching... and I'm a "visual person").

The striking and somewhat distinctive quality here, and perhaps somewhat unprecedented anywhere (not just Iceland) is just what *does* happen when a volcano that is self-built after hundreds of obstensibly rhyolite (plinean) eruptions becomes intruded by basaltic magma?

The "plumbing" is there. All that brittle, crusty, pre-shattered layers of concentric rock are in place... riddled with fissures and old pipes. The fissures have seemingly been highly permeated by water from groundwater and the prior year's accelerated melting... and whenever magma intrudes the ultra-hot, high-pressure steam generated helps crack apart those fissures during the intrusive phase.

After the magma partially retreats in the cycle (having melted all the seam walls smooth and slowly but surely turned contacted rhyolite at the margins into soft putty) water probably continues to intrude and burst into steam, filling pockets and smaller seams above the magma.

@passerby, bruce stout, jón - I hope my colourful analogies don't cloud the hypothesis (the legacy of a lifetime of teaching... and I'm a "visual person").

The striking and somewhat distinctive hovering question here, and a perhaps somewhat unprecedented situation anywhere (not just Iceland) is just what *does* happen when a volcano that is self-built after hundreds of obstensibly rhyolite (plinean) eruptions becomes intruded for the first time by basaltic magma (breaking into its pre-existing plumbing)?

The "plumbing" WAS there. All those brittle, crusty, pre-shattered layers of concentric rock were in place... riddled with fissures and old pipes. The fissures had apparently been highly permeated by groundwater from the water table and the prior year's accelerated melting... and whenever magma intruded, the expanding ultra-hot high-pressure steam helped crack apart those fissures during the former intrusive phase.

After the 1100° basaltic/andeasite magma partially retreated in the cycle (having melted all the seam walls smooth and slowly-but-surely turned contacted rhyolite at its margins into soft putty) water probably continued to intrude and burst into steam, filling pockets and smaller seams above the magma.

Then, after about thirty to forty hours, the next pressure wave of ultra-hot basaltic magma arrives - vapourising another huge batch of water into steam, re-pressurises the channels where hot magma had been just sitting, and pushes everything upward and outward again. By my guess, all the strata just keeps getting softer when in contact with the hot basalt... it wasn't "designed" to deal with such high temperatures. It was "born" of cooler processes.

If (as I alluded) the slow deconstruction of pathways and fissure networks is going on inside there (and the most recent activity seems to focus all that melting-sludging energy to the northeast side of the caldera, between the surface and approximately 4 km down) then I would certainly still worry about secondary or tertiary vents opening on Eyjafjallajökull's south and SE side - new fissures that will spill out extensive magma by-products of that internal melting... and undermine the side face of the mountain.

Loss of structural integrity could happen, but I can't propose that with any sense of certainty yet as no geologist has answered the question I raised last week... "what is the geologic strata lying under and around Eyjafjallajökull? Can anyone point out a detailed map or paper indicating the composition, integrity, and geologic stability (or not) of the principle mountain ridges and hills which surround the caldera?

If basaltic magma is, under pressure, finding its way for the first time into the innards of the formerly rhyolitic mountain (where there are at least some water-rich areas) an explosive eruption is still not out of the question. And given the potential "weakening" of Eyjaf's internal rhyolite structure by it melting and softening wherever it is near or adjacent basaltic magma, once it starts coming apart (or coming down) it may come apart in unexpected ways... including toward the sea.

Back to the question of tsunami alerts and how quickly they can be activated, and whether ties with other governments have been made... and whether anyone listened?


I apologise for the half-started post. All my applications crashed simultaneously while I was mid-entry. The Hewlett-Packard software I used to make the panoramas earlier in the evening had a live connection to a remote URL which I think triggered the crash.

@Michael.C.B - I have tried to locate the position of the active area on google maps based on position from Institute of Earth Sciences, University of Iceland. The erupting fissure appears to be a little North than what is pointed out in your map. Please correct me if i am wrong. I also located the position in another publically available Imagery from NASAs archives. Its resolution is decent but not as good as the Google maps.

Please visit and let me know. Thanks!

Erik posted a group of citations that include an MS thesis. In it, there is a map graphic and in the background section, a brief description of the mixed types of magma deposited at Eyjaf. That thesis describes a NW flank fissure eruption that has quite different deposits than the more typical alkaline basalts that probably underlie the active eastern flank fissure group.

Please look at Rudi's post, blog page above this one. He shows interesting crater formations that sit atop the long E-W trending fissures close to the present eruption site. They also appear on a detailed topo (hiking) map.

They appear to be intersecting volcano-fissure complexes (Eyjaf and Katla). Fissure eruptions are very common in the Eastern Volcano Zone.

I urge you to run a Google search on the term Iceland Hot Spot and Iceland and Mid-Atlantic Ridge and Mid-Atlantic Rise.

The Rise is quite important here because of the unusual elevation of the Ridge under Iceland.

The 'Hotspot' appears to have path discontinuity at depth. It is also not very hot, and is therefore a hotspot anomaly. The spreading Ridge appears to have much to with large eruption, dike formation and dike-fissure intrusion dynamics in the EVZ, and the variability in deposits, as well as the tectonic strengthening of the SISZ.

You will also find interesting discussion of the differences in magmetic deposit chemistry. Much of Iceland's magmas are described as being dry (low water content), but there are conditions under which 'wet' (high water content magmas) occur. These differences in degassing and accumulating tectonic stress are linked to the type of eruption dynamics.

There are 4 different blogs for the current eruption here, so I repeat 2 links to my posts at about the use of Google Earth for photo and viewpoint identification purposes:…

(Passerby mentioned my Rudi's post…

from above).

Well, sorta. Overton is explaining effects that exist on a *much* larger scale.

He is about half-way up the food-chain of cause-effect linkage.

LOD is important.

Passerby, I was thinking more in the lines of linking the coriolis effects at nothern lattitudes to the solving off the ocsilation anomolies.

Also the on going discussion at to why there is not trail debris in regards to Icelands hotspot.

But you are correct, he speaks to a more global tectonic ear however, he is a hoot to read@!

Passerby, I was thinking more in the lines of linking the coriolis effects at nothern lattitudes to the solving off the oscillation anomolies.

Also the ongoing discussion at to why there is not trail debris in regards to Icelands hotspot.

But you are correct, he speaks to a more global tectonic ear however, he is a hoot to read@!

Speaking of regular oscillations, look at the THEY graphic referenced in one of the last posts, top thread on this blog.

If you trace the oscillations and pick out the peaks, and drop a vertical line on each peak to x-axis, you should see a fairly regular progression.


Socuel's wire diagram…

has been bothering me, because the base cube graphic ('bottom' of the cube) looked familiar.

I posted a very useful citation, 'Response of glacier mass balance to regional warming, deduced by mass balance on three glaciers in S-Iceland.' S Gudmundsson et al. This is a pdf document of a poster session presentation.

Under the Section, 'Specific Mass Balance', look at the left most colored iceland graphic, Maps of Average Annual Elevation Changes (two side-by-side maps, showing elevations changes for the periods 1984-1995 and 1996-2004.

You should see a relatively nice match-up between Socuels shallow EQ pattern and longterm recession at the glacier boundary for Eyjaf.

You can see why I brought up glacier recession as an important mechanism for explaining some of the emerging graphed data patterns.

In more than a few documents, it's exceptionally obvious that the Holocene eruption history of Iceland is dominated by glacier recession.

This is one of two pervasive correlation patterns that fit historic eruption dynamics at the Eyjaf-Katla volcanic center-fissure complex.

@passerby - I agree completely about glacial recession. I made an earlier post in that regard reinforcing your conclusions about the reciprocal relationship between decrease of ice load with increase in volcanism. And this paper traces several evolutions in Katla's plumbing over the course of the Holocene -

For cultures who lived around the North Atlantic (beyond the glacial cover) near the end of the Pleistocene, the relative calm of those times was shattered with the onset of the Holocene for that one reason, and others as well. Not only did the oceans rise 125 metres in about 12k years (between 20k and 8k yrs BP) but the surge in Icelandic volcanism repeatedly wrecked havoc with the climate and the oceans. I imagine from their point of view the world went to hell in a handbasket.

We're now due for a minor version of the same thing as Icelandic volcanism increases again... there's no reason why it shouldn't.

By the way, I asked Michel Socuel if he could increase the size of his shallow quake wireframe to include the area of the eruption and all the way to the edge of the Katla caldera (-19.2 or -19.1 East). He's going to do that, gracious fellow, when he returns from a trip on Monday.

Thanks for the prompt to Rudi's observations. I haven't been up on Myrdalsjökull or Eyjafjallajökull, but did look closely at some recent trekking photos posted by a Sierra Club group coming down the northern flank and turning under the north slopes of Eyjaf. Those obviously are not basaltic ridges such as you see on the other side of Katla or on the coast near Vik... but loose mounds of compacted tephra accumulated over millenia and very subject to water erosion.

If that's what Eyjafjallajökull is composed of primarily (except directly to its west, where it abuts Katla's basaltic western containment ridge... its "cauldron" as it were) then I can see how water intrusion is likely, and also how newly-directed basaltic lava would have a very easy time of it - basically tossing and melting this semi-loose stuff out of the way.

How bad an eruption we eventually have (I believe) depends entirely upon what has shifted/torsioned down far below over the past couple of years; how hot the "hot spot" has become; how much pressure is presently accumulated upon the Katla magma "reservoir" (whatever form it is in right now... I don't think it's following a historical pattern); and how cleanly that pressurized magma can open a path between the reservoir and whatever outlet (or outlets) it breaks/melts for itself... at the time... out of weakened strata within Eyjafjallajökull.

Oh, and I suppose you could add to that, how "wet" the fissures are that it chooses to break through... if they are loaded with water, or linked to seams that are fed by the water table, then the extremely hot magma has an additional tool with which to pry apart the mountain (explosive steam).

In such a scenario you have an uncannily similar situation to the one I previously cited from Simon Day vis-a-vis Cumbre Viejes - a rare combination of circumstances (now existing) where retreating magma from the last eruption was replaced not by collapsed rock or simply a void, but leaked-in sea water. The next time the magma comes up into there (the pipes), they are anticipating an explosive sheaving of rock and a slope failure of such magnitude... well, that's not the point here, because we don't know where magma will break through in Eyjafjalljökull next.

But please, somebody contradict me if there is more "strength" in Eyjafjallajökull than I sense from my reading, hunches and remote observation. If there is an underlying basaltic structure (an early extruded ring dyke perhaps?) that will help keep the mountain together in the face of the present cyclic assault, please let me know.

And it is SO quiet now. Really, really quiet. Only a few quakes shallower than 2km in the past 24 hrs - most of the relatively few others have been 4 km. or deeper.

Is it taking a breather? Or is it a pitcher winding up for a pitch? With the adjacent dome and ridges still deforming upward and twisting, I cannot believe this is the end of anything.

About basaltic magma behaviour in a shallow rhyolite fissure network - does anyone know? If the magma cools this close to the surface in a NON-basaltic eruptive tube or seam, does it form a plug?

Is there any danger here that if the magma doesn't keep the fissure open, it will seal in a quasi-permanent way, and the pressurized deep magma (the next time it comes up) will have to find a different point of egress?

So, the latest from the front lines, as it were.

The volcano has FINALLY begun to deflate. GPS readings from the new instruments on the ridge to the north and south of the eruption site confirm this.

The volcano is exhibiting very strange behaviour, though. It's actually increasing in activity, rather than decreasing as you would expect. This may be why it is finally beginning to make a dent in the volcano's pressure. No signs of it stopping any time soon, though.

Also initial estimates of the fissure length were wrong - from the ground it's been measures as about 250 m long.

I took a trip out there again (third in four days) yesterday and the weather was much better. STUNNING views. I lucked out with access, too - seems like the road is almost always closed. I took some pretty spectacular photos if you guys are interested:

Great images, James. Am I correct in noting that the steam expulsion is mostly from the northeast end of the fissure? That would be right under the Brattafönn ice field, right?

So is it possible that there is a miniature melt going on there, which is feeding fairly constant water into the vent... heard any analyses yet?

I've yet to hear back from any sources whatever, spelling out the geology of the area on either side of the ridge there, but most on-the-ground imagery I've examined suggest a lot of compressed tuft and tephra, and some extruded fairly lightweight looking magma (presumably rhyolites and occasional mixed gabbros) from past eruptions.

The north side of the Fimmvörâuhálsskáli ridge (toward the Krossá riverbed... the side it looks like you climbed up from) is heavily climate-eroded, so there sure doesn't look like any rigidity or basalt mixed in with it).

So water permeation into and throughout the internal seams of Eyjafjallajökull at even its higher altitudes feels like a definite possibility, especially with generalised climate warming and de-glaciation. The arriving basaltic magma could run into seams loaded with water here and there. What's your impression?

@James, That deflation you speak of might not last long. As I think more magma is coming from the deep soon, or is already there. We might see some interesting activity in the coming days and weeks.

The newest set of quakes seem to all be staying in or near the upwelling point rather than moving eastward toward the opened fissure, which feeds my suspicion that the magma in the direction of Myrdalsjökull is cooling and forming a partial plug.

I believe there is a possibility that a subsequent upthrust of magma from the deep reserve may bring a breakthrough in different location... either under ice or out on the seaward slope. More details on my blog - and also some collected photos of this eruption, including a closeup of the fissure itself, and a photo of the Brattafönn ice field location before the fissure erupted through it.

I should have qualified my comment about the more recent Icelandic eruptions, in that the 1996-7 eruption at Grimsvotn, under the Vatnajokull, created a jokullhlaup which destroyed part of the main road around the coast, less than 25 years after it was built. There were significant economic implications

By Averil Wootton (not verified) on 26 Mar 2010 #permalink

First, this si my first post. And, as a amateur, i have learnet a lot from this site!

Since there has'nt been any new traffic on this blog for a couple of days, I'll try to awake it...

On the webcam there seems to be a new disturbance. Is this caused by a new crater/fixture or is it the magma taking a new course? From what i can see on the webcams, it seems the amount of magma is accelerating, is that correct?
Thanks a lot for the learningfull info gathered here!!!

Best regards

By Tonni Hauge-Moeller (not verified) on 30 Mar 2010 #permalink

I've posted the source NASA image for the fissure vent at Fimmvörduháls plus several panoramas of the HrunagÃl gully or gorge, to help folks visualise where the lava and mini-lahars are heading.

@Erik Klemetti - thanks for your suggestions at page top at "Eruption Update for 3/24/20", for how to evaluate the interface between basaltic magma and a rhyolite volcanic mountain... very interesting and informative.

hey everyone
, the ash that erupted from the volcano has engulfed around 85% of the british isles , and making its way east-ward across europe. it is unconfirmed at the moment but i have heard that it has grown in size and is now over france , belgium , russia and other europian countries. I myself am worried that the earth quake earlier today will trigger the eruption of mount katla which may cause a larger more agressive ash cloud resulting in the bloting out of the sun on a near global scale. This would result in the inabilty to grow crops and inturn would leave animals with out food, essencially screwing up the eco-system. Bluntly i am talking about a lack of food , the ash fall would pollute water supplies meaning clean water would be damn-near impossible to find, fighting would erupt over things as simple as food and water. If we think the world is screwed now , then we are about to get the shock of our lives.

Thank you for all of the posts which I have read with great interest, apart from the last I must say...I presume this means I should try and get a refund for my flight from the UK to US next week...

Should I be buying water?
..and a sun bed?

Jokes aside, I am very curious to know if Mr. Billingsley has anything to add to zero's comment on April 16th. Thank you.

By Butterfly (not verified) on 17 Apr 2010 #permalink

Some interesting comments I learned a thing or two here but what I will comment on is the lack of comments for the Apl 14 large eruption! You would think that would be more discussion worthy than the first smaller one.

A question I have is, people were going up to the crater every day to take pictures, what happened to them when it went off big time? Dose anyone know if anyone was killed? Or even can you know, as they would probably never be seen again? I haven't heard anything about people being killed up there. Are there any missing person reports?

Another question is, does this appear to be done now or can we expect more from Eyjafjallajökull. I suppose no one can say for sure.

This is the worst blog i've ever seen.
I am the biggest volcanoe blog critic in the world and i think your blog sucks
i give it -3 stars out of 5