Iceland Eruption Update for 3/24/2010

The fissure vent eruption near Eyjafjallajokull in Iceland. Image by Ãorsteinn Gunnarsson, March 22, 2010.

It has been hard to keep up with the flood of news from the Eyjafjallajokull eruption in Iceland. Eruptions readers have done a good job with getting new images, videos and info up as they happen, so you might want to peruse the comments for those sorts of tidbits (along with discussion of what might be happening).

Here is the latest:
The eruption at Fimmvörduháls (considering the eruption is actually occurring between the ice caps) could last weeks to months, which isn't too surprising for a basaltic fissure event. So far the amount of erupted basalt is relatively small, with most of the lava confined to the area around the fissure and what looks like a drainage the lava is exploiting that heads to the northeast. There also seems to be indications that some of the fissure is coalescing into a spatter cone/scoria cone - where you can see how asymmetrical it is thanks to the wind most likely (see above). Icelandic scientists were able to take samples of the basalt, so we will hopefully know some more about its composition in the near future, but Dr. Haraldur Sigurdsson, the most famous of Iceland's volcanologists, sees this eruption as very similar to the 1973 eruption in the Westman Islands. As of Monday, the fissure lavas have covered ~0.34 km2

There are quite a few webcams up where you can watch the eruption, just showing the technological world we live in where I can watch an eruption in Iceland live whenever I want. You can also see a pile of images taken by people on The eruption is actually "open for tourists", much like many of the eruptions in Hawai`i. This is not to say that it is safe to head there outside the bounds that the Icelandic government has set, but many people could get the chance to see a fissure eruption first hand (ah, if only for the time and the money).

There has been a number of articles I've seen that have pondered the global consequences of this eruption - mostly thanks to whatever aerosols like sulfur dioxide and carbon dioxide - might have on global climate in the short term. Right now, I would say that anyone being definite about what might happen is, well, full of it. Many of the articles have been making a big deal of the Eyjafjallajokull-Katla connection because "historically" when Eyjafjallajokull erupts, Katla follows. However, the key here is "historically" - even with the relatively long record of humans on Iceland, any historic record is much less than the lifespan of these volcanoes. That is not to say it won't happen, so Katla should be watched closely.

Also, there has been much discussion in the Eruptions comment about the nature of volcanism in Iceland and the relationship between the seemingly rhyolitic history of Eyjafjallajokull and this basaltic eruption. Well, we know that rhyolite melts can be produced in this rift/hot spot setting, thanks to the direct sampling of such melts, so the fact that the volcano was rhyolitic previously is no surprise. It actually isn't much of a surprise that you can get a basaltic eruption in a rhyolitic center, either. It is called "bimodal volcanism", where you can have the same volcano (or nearby volcanoes) erupt both basalt and rhyolite, almost contemporaneous. In fact, I've worked on a volcano with a similar history, that being New Zealand's Mt. Tarawera, where the history of the volcano was dominantly rhyolite until the most recent eruption in 1886, which was a basalt. This basaltic eruption didn't trigger any massive remelting and eruption of the underlying rhyolite mush from previous eruption - although you can find nifty melting rhyolite chunks in the basalt. If you actually do some of the calculations, it takes a lot of energy to totally melt a rhyolite mush to the point that it might become eruptible (>50% melt?), so this small amount of basalt at Eyjafjallajokull doesn't seem like enough so far - and anyway, what you really want is the basalt to pond under the rhyolite, not blast right through it any erupt.

{Hat tip to everyone who has posted links I used in this. Keep up the good work!}

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Erik, As of Monday, the fissure had erupted ~0.34 km3? is that correct? What would that place it on the VEI scale? I thought a VEI 4 was around 0.1Km3?

Simon - It is hard to translate the VEI into dominantly effusive eruption, so I would be wary of just looking at the erupted volume as a gauge.

Simon - VEI is used as a semi-quantitative guage of how explosive an eruption is. It takes into account things such as eruption column height as well as the amount of erupted material, which in an explosive eruption includes ash. As Erik said this mainly an effusive eruption, so explosiveness relly isn't a factor. Fountaining like you see isn't considered to be much of an explosive event and really doesn't make a true eruption column. There were earlier "phreatomagmatic" or steam blasts when the lava interacted with surface water, but those were passing events.

Thanks for the explanations, it confused me a little bit, but then alot of things do so its no real surprise lol.

New pictures of the stream of Lava falling down from Fimmvörduhals towards the valley floor:

I am totally fascinated about this eruption, since I hiked across Fimmvörduhals last year and cannot wrap my head around the fact that now there is a volcanic fissure across our path.

I like the new camera view on webcam 2. Also it is nice to see some blue sky for a change :) Unfortunately the weather will start to get bad again later tonight.

By Mattias Larsson (not verified) on 24 Mar 2010 #permalink

I think that this is just a start of a eruption cycle in Eyjafjallajökull that is going to last one or two years.

But everything is normal at the moment in eruption and nothing important happening at the moment.

You are missing an ideal opportunity here, Erik

Since you brought up Mount Tarawera, why not paint in the conceptual connections between Plate-plate boundaries, Rifts and Ridges?

Start with the The Taupo Volcanic Zone and Back Arc Basins.
See: Wiki page on Rifts and the map showing major plates, then talk to us about back-arc basin rifting.

Help us to better understand Eyjaf, EVZ rifting and bimdodal volcanism.

It would appear that something is happening on the webcam

Erik, 50% melt...what happens at 50% that makes it more likely to erupt? Also wouldn't you say that the higher the overall melt percentage, the more likely it would be for that 50% to be concentrated and reached locally in a smaller part of the magma chamber?

Passerby - That would like fill multiple volumes to make those comparisons - but it is an intriguing idea.

Randall - the 50% is just when a mush is no longer rigid and loses cohesion. The eruptibility is a combination of the % crystals and temperature, related to viscosity. Too viscous = no eruption, or at least a passive dome-forming eruption. I'm just trying to say to mobilize all of the mush under Eyjafjallajokull or Katla takes a lot of energy to make it out of the "rigid" field into the"liquid + crystals" field ... but yes, you could also extract the liquid into a smaller volume under the right conditions.

I was reading Manuels #4 link and appearently Melimoyu means "four tits".

Interesting name for a volcano. But there are some strange mountain formations on the top that the name probaly refers to.

By Mattias Larsson (not verified) on 24 Mar 2010 #permalink

Manuel Humeres:

Ps. I am sorry for my English.

Whyever for? It's fine (and vastly better than the Iberian languages of just about any of us.)

By D. C. Sessions (not verified) on 24 Mar 2010 #permalink

I'm looking at Webcam2. To the left is a large steam plume and at centre right there is a blacker, more ash-driven plume (below the Securitas advert - is the latter the eruption? and the steam plume where lava is meeting ice?

Sorry, I've just come in from work and have only just logged into this site.

By Anne Cotton (not verified) on 24 Mar 2010 #permalink

While Erik contemplates Passeby's suggestion for some background discussion on Taupo etc., I thought the non-geologist readers could use a liitle glossary to help follow some of the discussions.

Rifting: The splitting of crust due to tension. Can happen wherever there is tensional stress, particularly, but not limited to divergent plate boundaries. Rifting allows the crust to extend and accommodate tension. Rift formation occurs as faults oriented perpendicular to the direction of stress develop and often results in a series of connected down-dropped blocks known as grabens.

Divergent plate boundary: where two plates move away from each other. Crust in boundary area is subjected to tensional stress and rifting. Partial melting can occur as upwelling mantle undergoing pressure-release melting.

Mid-ocean ridges and rises: Also known as oceanic spreading centers. Divergent boundaries in the oceanic crust are defined by either steeper ridges or gentler rises. Oceanic spreading centers are marked by grabens, earthquakes (rarely felt) and seafloor eruptions of basalt. Ridges and rises stand above the surrounding seafloor due to their being comprised of newer, warmer less dense crust. New oceanic crust (basalt and gabbro) forms at oceanic spreading centers and moves away. Do not have to be located in the middle of an ocean basin. Examples- Mid-Atlantic Ridge, East Pacific Rise

Continental Rift Zone: a divergent boundary or an incipient boundary cutting through continental crust. Marked by long, narrow rift valleys and both basaltic and rhyolitic magmas. May continue to open and form a new seaway. Example- East African Rifts and Red Sea.

Back-arc basin: a zone of tension, extension and melting that occur behind a volcanic arc in a subduction zone. Subduction zones are convergent plate boundaries and back-arc basins are not considered to be separate plate boundaries. Although the stresses in a subduction zone overall are compressive, there are circumstances that cause tension behind the arc and create back-arc rifting. Back-arc basins operate similarly to oceanic spreading centers and erupt their own flavor of basalt. Example â the Mariana Trough (NOT to be confused with the Mariana Trench).

Here you can download a google earth file that has the hiking trails as a track, some geotagged pictures, and two image overlays showing the eruption: double klick on the overlays in Google Earth to fit them into the landscape.

Someone wake me up when the EQrate oscillations start again.

By Peter Cobbold (not verified) on 24 Mar 2010 #permalink

@Simon (comment #1), 0.34 km3 as a volume of this eruption seems to me like at least two orders of magnitude too high. If it's 0.34 million cubic meters, that seems more plausible to me. This eruption is very, very small so far, and if you look at the last Hekla eruption in 2000, that one was quite big and produced less than 0.2 km3, and the Pu'u 'O'o eruption of Kilauea (that's the eruption still continuing since 1983) produced some 0.3 km3 during its first YEAR.

I would give this eruption at best one million cubic meters so far (that is, 0.003 km3).

Sorry, that should have read "(that is, 0.001 km3)" in the previous post.

As for the volcanic explosivity index, this eruption is probably no more than VEI=1

Great pictures on Channel 2 News tonight, what you see among other things is lava falling over the edge of a cliff, a 200m drop.…

The first 3 news stories are about the eruption (starting with 'Hraunfossinn stórkostlegt náttúrufyrirbæri').

The video takes some time to start up and then you may have to double click the image (that's at least what I had to do).

The greatest weakness of the VEI index is that it doesn't quite allow for time. Perhaps the most stark example of this is the Siberian Traps, labelled as the "largest volcanic eruption in Earth history". At first, the estimated total volume of 3,000,000 cubic kilometres seems very impressive. But when you figure time into the equation - the main phase of the Siberian Trap event is quoted as lasting a million years - the average volume slips to a modest 3 cubic kilometres per annum. On a dayly basis, the Siberian Traps emitted no more than ~0,008 cu km per day which makes the event only about 20 times as impressive per day as the current Eyjafjöll eruption. What is remarkable about it is the time the eruption went on for and of course there must have been years when mighty eruptions did occur, (Wikipedia gives a figure for individual eruptions of up to 2000 cu km) but on average, per year, it was not that impressive.


All I can say at this point is WOW!! The videos and pics coming out are just fantastic and it is so cool to be able to watch this take place. Amazing.

Thanks to all of you for such good info and also the great links.

@ Peter

Don't go to sleep !! Please! I'm already going through withdrawal here after the heady days of leading up to this and you disappearing is not going to make it any better!

Did you see my comment the other day? (#174 in the Eruption Started thread) as a possible explanation for your bouncing bolus?
Basically it is not the bolus but the the crust that takes up the kinetic energy of a body of magma rising from underneath and it is therefore the crust which bounces, as seen in the oscillating GPS readings for Godaland? I have no idea how feasible this is nor how this could translate directly into the organized pattern of seismic activity but it came to me when you talked about bouncing boluses. (great band name by the way ;-)

By bruce stout (not verified) on 24 Mar 2010 #permalink

To continue with the Bi-modal magmatism theme. Lots of eruptions in Iceland have this form. I took part in a study of Askja some years ago, led by Geoff Brown. Not only were the products of the 1875 eruption highly acidic, but a survey of the rock types making up the caldera wall revealed a number of rhyolitic pockets.

By Richard Oliver (not verified) on 24 Mar 2010 #permalink

@ #26. Boris, I was taking that figure from that given by Erik in the article. I honestly though 0.34Km3 seemed incorrect.

What is the original source for the number 0.34km3? It sounds a bit large but I don´t have enough experience of lava flow eruptions to have a intuitive feeling of how much material that has escaped the volcano in this eruption.

By Mattias Larsson (not verified) on 24 Mar 2010 #permalink

Simon, Boris and Mattias - My mistake! I misread the report ... the flows have covered 0.34 square kilometers. The volume of the flows is much smaller, but no number is offered in the report. Sorry!

@ Bruce 35. Matchsticks are propping my eyelids. All this talk of webcams , videos, pdfs from IMO is exasperating. My abode is right out in the sticks, so electrons piling up in my phone line, hence dial-up 26kbsp. Got to go satellite.

Yes I was thinking this evening along your lines, having missed your ealier post. Flexing of the crust as the magma bolus piles into it, maybe like this?:

1 Initial contact of bolus until half sphere squeezed flat= upstroke to top of first spikelet. Crust deforms into shallow dome. Tension-induced near-surface EQs (compression-EQs deeper?) Peak EQs as half-sphere flattened: max rate of deformation around here
2 Fall to plateau= tail of sphere pancakes also.adiding mor doming but at reduced rate as volume of sphere diminuishes.
3 Plateau= bolus now fully pancaked, kinetic energy spent. Dome fully developed, crust strained maximally, EQs continue.
4 Magma pancake resumes minimum energy shape (sphere), deformed crust flexes ( elasticity required) from dome through flat to dish and back to flat = 'off' spike.

Overall the sequence is not symmetrical. The 'off spike' should be less pronounced than on spike beause less energy being input. But recorded EQs looks much the same 'on' or 'off'....

When I look at the trace from 16th onwards I get impression of a damped oscillation. ( But the two cycles in the basal EQrate could just be stochastic noise.) You too?

I think a prediction of this model - which could be tested -is that fracture-induced EQs (which I think can be distinguished from othe types- need help here!!) would be shallow when the crust is domed, deeper when it flexes into a dish. Socuel's graph gives a slight hint of this,but not substantially, probably noise.

The crust under Eya-Goda-Myr is around 20km thick or more:
So how big would that bolus of magma need to be, and how fast-rising to deform the crust?
That web article is also a reliable source of info (she is Prof.Geophysics at Durham UK) on the mantle plume. Iceland is unusual plume-wise. Note especially the blobs in fig 14. Have we seen the first physical evidence of magma blobs?
Mention the word 'first' in I'm awake!! Thanks Bruce.

PS I forgot the GPS data - let's chcek it over, but I think the published records are smoothed too much to see the crust cycle? James is very quiet on the odd GPS oscillations he heard about.

By Peter Cobbold (not verified) on 24 Mar 2010 #permalink

Is there a site I can find the SO2 output per day ?


By Dasnowskier (not verified) on 24 Mar 2010 #permalink

So knackered cant read page number properly;
page 17:
""Both uprising hot bodies and downgoing
cold bodies are predicted to start out with tabular morphology and then to become cylindrical.""

By Peter Cobbold (not verified) on 24 Mar 2010 #permalink

@David B, it can just happen. A friend of mine told me about a web site she wanted me to see and she told me the site name was "moose and more". (Don't go there by the way!) What she forgot about was that the site name was really "mostly moose and more". That site is ok. The other one was, well, let's just say it was a bit off color and probably had a virus. So stuff happens. You type one wrong word or letter and you get into something you wish you hadn't.

@Peter and Bruce, I have been following the bolus idea and I think I get what you are saying about it, but I am not sure. Is it a "blob" that forms, works its way up to the crust and goes flat or creates a dish form? Am I getting that right? Then another one forms and the same process goes on again. That is what I am understanding at the moment of the theory. Let me know if I am on track. I will continue to follow this as I find it interesting. Of course, I have been reading the threads since they started on this.

Ah, for enough dinero and time to get to Iceland.

@ Bruce
Severe brain fade: page 19
Third time lucky..
@David B You think you've got problems...

By Peter Cobbold (not verified) on 24 Mar 2010 #permalink

blob bolus theory = lava lamp lava theory ;D

*eyes rolling back in head*
David B => Flyby spammer.

@Parclair: that's what I thought.

Blob/bolus theory=Lava Lamp theory= convection current theory. ;-D

re bouncing crust... I am very uncertain about it being an explanation for what we have seen, but not only did the earthquakes follow a wave pattern but the GPS uplift also shows a sine curve.. taking the bouncing analogy again what I think might have happened is this:

At depth (i.e. below the crust) there is an upwelling of fresh magma that impacts the crust, thereby lifting it. The following oscillations in the uplift recorded at the GODA GPS show the crustal rebound from this one event, not multiple plumes of magma.

In the crust, itself this oscillating movement facilitates normal tectonic movement on the Eyja fault and the surroundings AND magma intrusion of basalt from the mantle/crust boundary which then takes on a life of its own, coming in waves that are also to some extent an expression of the wave form of the flexing crust.

Sounds neat, but personally I have doubts that the deeper plume would have that sort of kinetic energy to make the crust wobble like that.. any experts want to chip in here? It would also assume that there are deeper convection plumes in the mantle which I understand is disputed by some. Then again I can't think of any mechanism to cause that sort of wobble in the crust, unless of course we simply had a very ordered pattern of intrusions, one following the other.

Now I'll go and read your link Peter and find out where I'm wrong! :-)

By bruce stout (not verified) on 24 Mar 2010 #permalink

The eruption continues with more strength today then yesterday it seems. The lava is also on its good way to fill up a canyon that it is currently flowing into. They say that it should reach the lower area around Eyjafjallajökull in a day or two. There is also chance of the lava blocking rivers or changing the pathways in coming days.

@ Peter, Bruce, Diane

While blob boluses, lava lamps and convection currents are interesting and provide insights, I have been following your discussion with interest, perhaps another analogy would provide other insights? I'm thinking of the propagation of Marigold roots through thick tarmac seen upside down where the plant is analogous to the rising plume, the growing root system the magma and the tarmac as the jumbled-and-healed crust underneath a volcano. (If I correctly remember my school biology,) the roots explore the tarmac for cracks by shooting tendrils and when one is found, the plant raises the pressure by pumping water into the root which raises the pressure enough to move the embedded gravel in the tarmac, which is when earthquakes occur. Any periodicity is determined by the rate at which water/magma can be pumped up into the system and the resistance of the plate at the point(-s) of intrusion. Earthquake swarms would be analogous to the pressure release when the tarmac yields and an individual lump of roch is moved. Since in effect it is really water propagation through tarmac and magma is but a different liquid, perhaps there is some merit in such an analogy?

hi out there
i am ignorant of magma yet i have a magma question.
can the huge magnets at the cern haldron collider have an effect on molten metallic magma.?
ie; clumping towards the magnet.
can molten metals be magnetically influenced??

Thats depends on the temperature of the metals. But for most of them you are above the Curie temperature, where they lose any magnetic capacity. For iron this would be above 768°C. So speaking of lava, which has often above 1000°C the answer is no. LHC will not aggregate Lava and therefore generate a volcano.

I didn't get to follow the developments yesterday because I was running Ada Lovelace Day (celebrating women in science, tech and engineering), so now I find myself not entirely sure which links are new and which I've seen before!

I'm wondering, is there a wiki somewhere where we could collectively gather and annotate links? If not, I'd be happy to set one up some time today.

@59 Yanis
No worry,there is no way that the LHC could produce a volcano.
First, magma is not metallic. It is molten rock and is dominated by silica (a compound of silicon and oxygen. More importantly there is no magma being formed under the LHC site.

There is a common misconception in the mind of the public that there is a vast sea of magma beneath the crust and that the mantle beneath the crust is molten. Unfortunately, this misconception continues to be reinforced by some poorly researched popular science shows. The reality is that the mantle is crystalline, silicate rock that only melts to produce magma under very specific conditions in certain geologic settings close to the surface (generally within 100 km). The mantle does flow at certain depths, but as a plastic solid.

So, the latest from the front lines, as it were. I posted this in the old eruption discussion and didn't see that there was a new thread!

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:

Hah, someone already posted my Grapevine article a couple of posts above mine. :)

I've been quiet because I've been busy, sorry! I'm currently trying to get hold of a press ID or something off of the Grapevine, and hopefully a combination of that and scientific contacts in the university will allow me to get up close to it. Fingers crossed!

What size is the eruption? The fissure is 250m long (James) and the lava flow covers 0.34 sq km (Erik). First, 0.34 sq km is ~70 football pitches. Even if the lava pools at the bottom of the former waterfall, a ballpark figure for the volume of emitted lava would be on the order of 0.0001 cubic km assuming the lava if spread evenly over that area would be 1/3 m or one foot thick.

Using background features and comparing with a topographic map, taking camera angles into account, the scoria cone can be guesstimated to be less than 100 m high at its highest point. The base will probably be a roughly ellipsoidal shape measuring ~~200x350m. The volume of such a body would, again, be on the order of <0.0001 cu km for a grand total of ~0.0002 cu km, tops. This makes it a VEI 1 eruption spread over the best part of a week, or VEI 0+ per day (which is the figure Icelandic vulcanologists have stated - VEI 0+ to VEI 1).

If my guesstimates are wrong or there are other errors, please correct me!


Lovely pictures, thanks, and best of luck! You lucky, lucky... ;)

That BBC helicopter footage is great--but when will someone tell the Beeb that this eruption is NOT taking place under an ice sheet? Five days in, and they're still making that claim, despite their own film showing it just ain't so.


I like your analogy of the roots growing thru the soil, bit by bit moving the elements of dirt. I like it better than mine of bronchia clearing after a cold.


Wow on the pics, they're the next best thing to being there. Can we help you to get the press pass through recommendation?

Re the deflation with increased activity. I've noticed that the Halemaumau inflation/deflation cycle is not particularly connected with the amount of lava being pushed out any more. It's as though an equilibrium is reached at a certain point (it think of it as all the obstructing rock being melted); the underlying mechanism for lava push taking over. (Sorry guys, amateur thinking--all the stuff coming out of a volcano that's melted rock I call generic lava.)

At the same time this flank eruption is occurring could magma also have been injected into the rhyolite chamber underneath the volcano? The heat flux would re-mobilize the rhyolite just enough to trigger an eruption in the near future. Even if the basalt flows back out of the chamber the heat transferred to the rhyolite would remain, que no?

Is that an ice field or the ocean showing in the background of the Ãórólfsfelli cam today. I think ocean, because I think this cam faces south. (I'm getting disoriented because of all the outstanding views linked from the threads) Thanks


Anything is possible. Halemaumau is one of two leaky spots on Kiluea (Pu'u'O'o being the other, the one that's building the shield at such an impressive rate.)

Link to Kiluea:

@James, I have posted a blog warning about people being on top of Eyjafjallajökull. The pressure might be decreasing at the moment. But if the earthquakes that are happening are any clue, that pressure should start to increase in the next 12 to 24 hours, and it is going to increase fast. A lot faster then in last three weeks. I am expecting a movement up to 5cm/day when this starts for real. I base my model on the earthquakes that have been happening, and the theory that the deep supply of magma has not stopped as many scientists are expecting.

This eruption now is just the warming up of the Eyjafjallajökull in my opinion. This eruption is going to take at least ~12 months until it is finished.

Looking the Webcam 2, it seems that lava changed his direction.
This afternoon there is a big plume just at back of the scoria cone, and not far in the left of the cam as it was yesterday.
(sorry for my not perfect english)

By Dario Leone (not verified) on 25 Mar 2010 #permalink

Right Dario (#75), it seems that a new lobe of lava has started moving across the snow, possibly a bit further south or east of the earlier flow. So if that flow also reaches the gorge, we might again see some major plumes rise in that place.

@71 kver

A few key points from an igneous petrologist (guy who studies igneous rocks):
First, even though there has been eruptions of rhyolite in the past, it is by no means certain that there is currently an eruptable volume of rhyolitic magma in the area. By eruptable I mean that there is a large enough volume of uncrystallized material close enough to the surface that a basaltic magma injection would destabilize it and cause it to move towards the surface.

Second: If there is not an eruptable volume of rhyolitic magma present, it would take time to create more. Rhyolites in Iceland can be formed when basaltic magma fractionate and melt and assimilitate high silica rocks such as diorite and granite. However, it takes a considerable amount of basaltic magma and TIME to do this. Note that I earlier said rhyolitic magma, by which I mean liquid. Once rhyolitic magma solidifies you have granite. A small dike intrusion of basalt into a solid granite mass has neither sufficient heat or volume to make any appreciable amounts of rhyolitic magma.

@Bruce, Henrik.
The mechanisms you propose are widespread globally, yet the spikes have very regular features that are unusual- so why have they not been seen before, many times? Apart from researchers often shelving 'strange' data they dont understand rather than publishing (Which may or may not be prevalent in this field of science, I dont know - its a social thing, but I've seen it first hand in biology)- I suspect the spikes are strange. Anything odd that might throw light on the plume debate in Iceland - hot or not?- is worth debating.

There's no doubt despite the lack of citations in the literature that magma rises - 'ascent' in the jargon- as it becomes buoyant relative to the bulk mantle phase. (I'm not talking convection).Indeed Prof Foulger's articles suggest that the only way the huge depth of central Iceland's crust (40km) can be explained is by ascent from the depths, and not from the mid-Atlantic ridge, which only builds crust 10km thick. There's no data to support peroditite convection driven by a 'hot spot': that's a widely accepted myth which she demolishes in her articles. So ascent of blobs or boluses of magma should be commonplace in Iceland, that's where most of it has come from.
So what is the ascending material? Ecologite, slightly warmer that the bulk phase,originating from Caledonian subducted plate possibly 250?km deep. It's predicted to be maybe 'a few 10s'percent fluid (which means to me a mix of fluid and solid rubble: ? vegetable soup!).It assumes cylindrical shape as it rises. Transit time? velocity of ascent? volume? aspect ratio of column? -- I've no idea. has anyone?? Possible effect on 20km thick crust- depends on size of cylinder and speed. Hands waving,yes, but got to have working hypothesis to put to test.
Why if most of central Iceland's crust derives from ascending magma columns have these regular-shaped EQ spikes not been seen before?- they should be really common. I suspect that is where Eyjaf has favoured their identification:
1. the crust under Eyjaf is 20km thick, not 40km, so more likely to be deformed by magma collision, so more EQs expected. [The data set at Eyjaf is not huge, rising to around 70 per hour at peak. A more resitive crust that reduced EQs four-fold to 15 per hour could well obscure the oscillation in noise from EQ from other causes].
2. Eyjaf erupts slowly -no well-formed central conduit or magma chamber. So disturbance by first magma column to arrive does not trigger immediate eruption.
3 Framented country rock of Eyjaf better capable of having small EQs triggered by a bump from below.
4. Significance of oscillatory pattern in EQs or GPS not recognised?

I suspect a train of separate magma column-boluses underlies ALL the EQ spikes, only the last were of size sufficient to excite an oscillation of Ejaf's crust. The small initial events that we thought had 1-day periodocity must have been smaller boluses. If rock is partly melting and delaminating from ancient subducted rock 250km deep we should expect a variety of sizes of boluses.And as a train not a single blob. If each delamination takes 200 years to break free, then we have Eyjaf triggered by sudden magma accretion from ascending columns, every 200 years.
The last diagram in the mantle plume web site article (Iceland and the North Atlantic Igneous Province) is also interesting becuase the trapped oceanic crust is depicted, for reasons explained in the article,at a steep angle. It follows that any lateral petrological changes along that subducted slab would, on the ascending columns model, also offer a further contribution the diffences in magma composition between volcanos eg Eyjaf vs Katla.

The oscillation if GODA GPS is interesting, but very slow compared with Eyjaf's EQrate patterns. I'd want to see faster time-resoved data to see if unsmoothed raw GPS daat picked up the bolus collisions- would be noisy but using the EQrate parameter to interrogate the GPS signal would be one route to picking out oscillatory signal in the noise.

If I were a young,ambitious geophysicist looking to make a name in science I would grab this oscillation concept and run with it. Where to start? Trawl archived EQ data sets for the more peripheral Iceland volcanos sitting on thin crust, search for oscillatory patterns with ca.1-2 day period,or even a regular time-course/pattern within a spike. Go on, make a discovery - that's a real buzz, beats watching fireworks!

By Peter Cobbold (not verified) on 25 Mar 2010 #permalink

#77 Boris, we will see it this new lobe will stop the alimentation of the old one, or both will be active.

Lava of this eruption don't seems so liquid.... it seems more a fall of incandescent scorias

By Dario Leone (not verified) on 25 Mar 2010 #permalink

One of the best things about this particular blog is the presence of so many high-quality intellects from different walks of life exchanging ideas, thoughts and (informed) opinions. It is too easy to carry on several conversations simultaneously, even in the same thread, which I find myself doing at the moment.

Jon! I am inclined to agree with your #74 as the pre-eruption eartquake activity was too intense to warrant a result as "meager" as this has been so far. Let's put some figures as to why:

To recapitulate, there were some 10,000 earthquakes in the weeks leading up to the eruption. Each M1.0 eq was equal to 30lb of TNT, each M2.0 corresponded to 900 lb and the rare 3.0 was the equivalent of 27.000lb of TNT. Even if quakes M1.0 and below were by far the most common, it takes 30 or more of them to equal a single M2.0. Therefore, the average was agreed upon as being M1.5 corresponding to 210lb - roughly 100kg of TNT per earthquake. In all, the energy released through earthquakes is the equivalent of - roughly - 1,000,000 kg of TNT or 1 kiloton, a battlefield tactical nuke.

My earlier estimate of 0.0002 cubic km emitted (lava + volume of scoria cone) would at rho 3.0 weigh approximately 600,000 tons. This gives a "yield" of ~600 kg of DRE per kg of "earthquake-TNT". I am not a vulcanologist, but to me it seems to be a ridiculously low return in comparison to other volcanoes. Erik? Boris? Gijs?

Peter! If you take a dry branch and make a recording when you break it, then make a plot, you would get a similar pattern, yes? Could it not be that the periodicity observed during this eruption has a similar explanation? Similarly composed rock strata, regular in structure, subsequently being broken?

As to a 200-year cycle for Eyjafjöll, does such a theory really hold water? Known eruptions ~900 - 1612 - 1822 - 2010, but there were two non-eruptive events during the 1990s(?) and how many more such events have happened in the past without any note for posterity? I know it's more of a philosophical objection - a philosophical Devil's Advocate no less! ;)

EKoh! I once dabbled in mineralogy and gemmology and I think you may have left out one key ingredient, water. At temperatures in excess of ~500C and at high pressure, water acts as a flux and dissolves crystallised minerals quickly, far more quickly than they would melt at a substantially higher temperatures.



The lava IS flowing, just not a huge amount of it. It seems to be producing basaltic a'a flows at the moment, from what I've seen.

@Henrik, you name it: there are non-eruptive events, also called failed or non-eruptions, which show high levels of seismic activity without magma reaching the surface. Likewise, high seismic activity can be followed, very logically, by a rather minuscule eruption. There's nothing strange about this. In a previous thread I cited the example of a very intense seismic swarm at Etna in 1883; that was probably some of the most intense seismic activity at this volcano in the past few hundred years, and it heralded an eruption that lasted two or three days, built a cone 8 m tall and emitted ten thousand cubic meters (that is, 0.00001 km3). And then there are cases of large eruptions that are preceded by very little or almost no seismicity - look at Hekla, it happens every time she erupts.

Some of you folks blogging here must certainly abandon the idea that the energy release of a seismic swarm is proportional to the magnitude of the ensuing eruption; there is no such correlation at all. You also have to consider that many earthquakes before an eruption are caused by the breaking of rock due the forceful uprise of magma. If the magma finds little weak rock to break through, it has do do more of an effort and thus causes more earthquakes. The degassing of the magma, on the other hand, produces a signal called tremor, which is different from what we saw during the weeks before this eruption. Usually in basaltic eruptions tremor sets in very shortly before magma reaches the surface.

While it is well possible that the current Eyjafjallajökull eruption is just the start of a series of events, it is equally possible that this eruption will fade out after a few more days or weeks and that will be it.

@Dario: the lava seems rather viscous indeed, which may be due to the low rate at which it is emitted. From the first analyses published in the Icelandic version of the Nordvulk web site this new material is an alkalic basalt, which is typical for the southern volcanic area (including also the Vestmann Islands, including Surtsey and Heimaey).

@Boris 82.
Thank you for your post.

Could I get a clarification? You said

'The degassing of the magma, on the other hand, produces a signal called tremor, which is different from what we saw during the weeks before this eruption. Usually in basaltic eruptions tremor sets in very shortly before magma reaches the surface'

Would I be correct in saying that a lower viscosity magma would show tremors starting closer to eruption, and that a higher viscosity magma would start showing tremors long before eruption?

I'm trying to understand the difference between a basaltic eruption (like Kiluea), and a more explosive eruption (Cascade Volcanoes), which tend to be high-viscosity magmas.

More thoughts and numbers on magma blobs.
@Henrik, Branch snapping: something like fatigue failure, jumping from stratum to stratum. Could be. But that would be commonplace, seen frequently at many volcano- and the spike pattern would be frequently observed, and published ad nauseam ('me too' articles fill the science journals!). To date no-one has said those oscillations are seen frequently. So I shall persist with the magma blob concept!

Here are some very ballpark guesstimates on:
How big is a blob?
How fast is it?
Could it shake the crust under Eyjaf?

Iceland's crust is on average 30km thick and 25m years old. So neglecting erosion that's an accumulation of 1km per myear,= 1m per 1000years,= 0.2m in 200 years since Eyaf last erupted.
If area of Eyjaf is 220sqkm then it has accumulated in 200years 0.04km3 magma under its crust. That is 40million cubic meters = 120m tonnes. If all that volume were in one blob it could form a column roughly 250m diam. and 800m tall.As the biggest spike took 36 hours to complete then if that time-course reflects the column squashing flat (OK Diane?)the velocity would be about 800/36 or 20m per hour.
Compared with the mass of the Eyjaf volcano (4000sqkm 20km deep) of 1.2 x10power13 tonnes, the blob weighs in at just
0.001% of Eyjaf's mass.

@ Henrik You're the ballistics expert here. Thats not going to seriously shake Eyjaf apart, is it? But could it vibrate the upper 10km of Eyjaf enough to trigger the spikes' pattern of Mag 1-2ish EQs? I argue it could. What's the TNT equivalent of that kinetic energy, compared with TNT equivalent in the total EQs?

Note all above ignores erosion over 25m years giving an underestimate of magma recruitment(maybe quite big).
Blobs of smaller dimensions might be regularly colliding under Eyjaf giving the past bursts of EQ activity. The pattern of those EQS should be probed for 'blobby' periodocity, not merely counted. That's science.
Now I'll go and hide as you all pile in with objections- that's science too!

By Peter Cobbold (not verified) on 25 Mar 2010 #permalink

Peter, thank you for naming me a ballistics expert, but you have to remember I was on the user side, not mfg, which means I was only taught the rudiments required to radiate unshakeable confidence in the ability of our weapons to do the job! The kinetic energy of your theoretical projectile is easily calculated - 1,851,851 kgms-2, roughly equal to that of a 3-inch shell leaving the muzzle at 800ms-1. (I had to calculate that three times to convince myself...) It only requires a propellant charge of some ½ lb to achieve this with the 3" shell. (I still do not believe it!)

On the other hand, HEAT (High Explosive Anti Tank) shells utilise a shaped charge to turn a specially shaped copper cone into a jet of plasma appx 12"-18" in lentgth at some 7000C where the front of the jet moves at 8500ms-1 and the rear at 11000ms-1. Thus a shaped charge of octol, weighing about 180g, can blast a ½" hole through 12" of armour plate even if the velocity the projectile travelled at was only about 200ms-1. I.e. kinetic energy probably isn't the answer in our case.

But what of this Peter? Imagine that there is an aperture at 20km of a given size that will only let though a limited amount of magma from your bolus and that at a certain point in pressure-resistance from above, the only thing that happens is that pressure rises. Now go inside the volcano and imagine a sort of Devil's Postpile structure of basaltic, hexagonal pillars where the gaps between is where the magma can propagate (very hypothetical). There is not much flexibility in these pillars, so at a certain pressure, they will fracture, possibly into shards. When they do, the magma can move on but it has lost energy a) by fracturing, and b) by assimilating the shards. When the magma column encounters resistance again, it does not have the energy required but has "to wait" for it to be supplied from below. I imagine a sort of heat/pressure convection/propagation/pulse mechanism to supply the periodicity to your bolus-theory. Not the greatest of hypothesi perhaps, but I hope there is some merit to it.

Boris! Thank you for your clarifications! If I understood it correctly, the composition and structure of Eyjafjölla is such that it requires so much work to penetrate, especially by "dry" basaltic magmas, that most of the energy contained in an eruptible body, sometimes all, is dissipated before an eruption occurs. Also, earthquakes associated with rising magma can have three causes; fracturing, degassing plus phreatomagmatic or phreatic events (direct or indirect). Degassing can only occur when the pressure gradient/difference between the magma and its surroundings increases beyond a certain point, usually close to the surface.

Taken together, does this mean that unless there is a "recharge" from deep below, the ongoing Eyjafjöll eruption will probably peter out within a matter of days/weeks? What would the signatures of such a recharge be, ie what to look for?

@Henrik #58, I like the tarmac idea. I have another one along the same lines...the mushrooms that push up on MY tarmac. LOL Anyway, I think they are mushrooms as I have seen one do that before. It take quite a bit of time for it to break through, but you can see how it starts to crack the asphalt ever so slightly and more and more as time goes on, and it pushes it up and a mound forms. Sort of like a dome. And it keeps cracking, the cracks keep opening up and finally the mushroom comes through. No convections here, but a pretty good analogy of how magma may be pushing up into an area of rock with a hard top on it. There is some gravel below the asphalt so the mushroom has to work its way around that much as magma has to work around solid rock, rubble, cracks, and such. It is not a fast process until the mushroom breaks through. Then it pushes up and grows pretty fast. Some of them can be three or more inches in diameter. Not exactly what you want to go though the tarmac. :-|

@ Henrik. Quite terrifying those weapons. I guess you never thought about breech rupture or other failure modes....?
I like your pressure/heat/propagation/pulse mechanism. It would certainly explain the sudden rise in EQrate at the start of a spike, as the bolus exerts its initial pressure. The sudden ending of a spike would be the bolus becoming fully flattened, exerting only buoyancy pressure and no longer contributing gently-administered (by weapons' standards)kinetic energy. In between we have the spikelets: maybe I am reading too much into the time-course of these. Perhaps with more spikes to analyse we'd find they are pure chance. So all we need to do is wait another 200years. (Yawn)
The only argument I can find against your model is that some of spikes' EQs were spread around the arcs' 30km length extending horseshoe-like from Eyjaf's focus. The area of contact of the putative bolus ( 250m diameter flattening to - what?) is relatively small. But maybe magma intrusion as per your concept could radiate somewhat in the intervening 10km of crust between the blob and the lowest EQs.
Ah!yes: The magma column flattens!! after it makes contact. So new opportunities arise to enter new fracturable gaps, as in your model, as the mushroom disc expands. So spikelets would be expected, and possibly fairly regularly as the flat area expands steadily over 36 hours to cover randomly-distributed fracturable gaps.

By Peter Cobbold (not verified) on 25 Mar 2010 #permalink

@Peter #85, I am not sure what you were referring to, but whatever you were saying it is ok with me. I am no expert in this and I just think and most of the time I come up with stuff that doesn't seem to fit. But I do have fun trouble shooting this stuff. I will have to read this particular post to get my head around it. My brain seems to go "huh?" whenever there are numbers involved. LOL Not always as it depends on the numbers.

BTW, you don't need to go hide. :-D

@Diane. It was oblique reference to your #51. I'm certainly no expert either. Numbers are not my bag at all either.
What I enjoy is the challenge of trying to understand a phenomenon - the spikes- that are so familiar to me in biology, but in a system (volcano) that I had thought would never produce such ordered patterns of EQs. It's just intuition that tells me they're important. So I want understand them - just curious.
As for ideas not fitting. You're in good company:there's very,very few scientists think logically. The vast majority try seeing things from all angles, trying to fit pegs into holes. Over and over until it clicks.Logical it aint!!

By Peter Cobbold (not verified) on 25 Mar 2010 #permalink

@Gordys Head slap. I remember looking at that and bookmarking it. Need to organize myself better.

So, given

'From the first analyses published in the Icelandic version of the Nordvulk web site this new material is an alkalic basalt, which is typical for the southern volcanic area (including also the Vestmann Islands, including Surtsey and Heimaey).' (boris 82).

the current eruption would be a low-sio2 basalt (per wiki "Alkali basalt is relatively poor in silica and rich in sodium." So this would be a low-gas magma.)

So, I'm not sure I understand why there's discussion of an explosive eruption. Does anyone want to help a slow processor out?

Parclair #92, I think the explosions they are expecting are phreatiomagmatic from the lava coming in contact with the snow. There have been a couple of these already and they ususally have a combination of steam and ash in them from the lava being rather explosive when it hits the snow. I think it is like heating a pan on the stove and checking the temp with a drop of water. Only this is the hitting cold. You get a lot of steam and hot ash or small tephra in with it. Usually I think it is fine ash and steam. It can really blow, though, under the right conditions. One reason I was concerned for the people in one of the films being so close to the canyon. You never know when one will erupt.

Diane, thanks for the explanation.

It appears from the Ãórólfsfelli webcam tonight that a new lava flow has started, flowing slightly to the West of North from the scoria cone, directly towards the webcam. Perhaps lava has started ponding in the cone, and has breached a low point on that side?

I already had a trip to Iceland planned for the next week or so, it seems that was very good planning! Can someone local please advise me on access arrangements; it sounds as though the civil defense people are being quite helpful? I hope to stay at the Hotel Ranga, and take a snowmobile somewhere near the fissure...

Mike (B.Sc. geology (Glasgow '88) but a NY fireman these days!)

@ Fireman 96

Not sure about renting snowmobiles, but you can get helicopter flights direct from Hotel Ranga:

Tour operator Nordurflug will offer helicopter trips from Hótel Rangá for ISK 35,000 to 50,000 (USD 269-384, EUR 202-288) per person, depending on the length of the flight.

Other helicopter flights are also available. See:…

Peter, re your #89: Can you from your experience find a model for energy transfer that does not require physically lifting a truly immense body such as your bolus against gravity. Your "120 million ton projectile" as an example would acquire 12.7 times 10 to the 9th power as much potential energy as its kinetic energy content if physically lifted 20 km. What about heat propagating through a magma "solution" in a manner similar to the "ion pump" (??) of plants or the Na/K in animals (my knowledge of biology is almost 40 years in the past). Cf the sun where the photons created NOW will not reach the surface in another half a million years or so. If we can do away with the physical movement of actual, delineated bodies "down below" and replace it with the propagation of energy THROUGH matter, then your bolus model becomes far more palatable to me.

@Fireman (#96), that does indeed look like a new lobe of lava which has started sometime early today and is making its way northward. It is actually nearing a tall cliff that you can see in a number of photos taken from the area where the webcam is located, so if it continues there will be quite a show. It does seem quite close to the cliff at this moment (08.45 GMT), se let's keep an eye on it!

I found another news media jewel this morning in USA Today, where there is still talk about the threat of a massive eruption from Katla, and the possible global cooling it might trigger:…

(1) Although Icelandic volcanologists have voiced concern about a possibility of Katla joining the party sometime during this eruptive event, I would expect there to be some notable geophysical unrest at Katla before she goes. Currently there seems to be no such unrest, so I would not worry too much except having all emergency procedures ready to be applied if necessary. And, even if Katla erupts, this would have potentially severe effects for the region but I think in historical time there have been only two eruptions in Iceland - Eldgià in 934 and Laki in 1783 - to have a global climatic impact, and those were some sort of flood basalt eruptions, each with a lava volume of >10 cubic kilometers.

(2) The USA Today report talks a lot about vast amounts of volcanic ash being pumped into the stratosphere during major explosive eruptions, and indicate that as the cause of global cooling. Well, we're nearly 3 decades from El Chichón (Mexico, 1982), when it was understood that it is not volcanic ash but sulfur dioxide that can potentially affect the climate. So even if an eruption is very large but delivers little sulfur dioxide, there will be no appreciable climatic effect - like Mount St. Helens, which was a SO2-poor eruption.

I think the new lava flow will drop in the valley to the west of Morinsheidi. Looking forward to what it will look like at dusk and dawn. Currently I am in the process of capturing webcam images for creation of a time-lapse animation...

I´m not an expert but I think there is a new lava flow now. I compared my screenshot of the mila-webcam:… with the new development at 9:30 (Iceland time). And it seems that there is a new lava flow. I don´t think it is a new fissure, because there is steam getting in contact with some snow maybe. Could become interesting in the night, because then we could watch a lava flown which is faced to the webcams side.

By Thomas Wipf (not verified) on 26 Mar 2010 #permalink

@fireman #96 I have seen two tours that look rather cool:…

If I had the money and time I would leap at a chance to go and see Eyjafjallajökull up close!

btw, I have to say that geology graduate -> fireman in NY is an interesting career trajectory! Mind you, I went from geology -> journalism -> technology, so I understand random! ;)

@fireman #96 I have seen two tours that look rather cool. If you go to, then click DayTours, there are two tours listed, one of which includes snowmobiles!

(I tried to post the URLs here but my comment got held for moderation, so I'm trying again without the URLs.)

If I had the money and time I would leap at a chance to go and see Eyjafjallajökull up close!

btw, I have to say that geology graduate -> fireman in NY is an interesting career trajectory! Mind you, I went from geology -> journalism -> technology, so I understand random! ;)

I think the new flow started to pour over the edge, but the new hraunfoss will not be visible from the webcam, I think it goes over at 63°38'50.20"N 19°27'5.34"W which faces more to the north-east.

@ Phillip, the steam plume from the second flow has been building all morning. At first I wasn't sure if it was just atmospheric or indeed the flow had gone over the edge. It looks as though the first flow has stopped completely and all flow is now directed towards the new outlet. Good strong plume at the moment.

By bruce stout (not verified) on 26 Mar 2010 #permalink

whoops, spoke too soon. Now two very strong plumes.

By bruce stout (not verified) on 26 Mar 2010 #permalink

@ Phillip, I think you are quite right. It would also explain the copious amounts of steam.

By bruce stout (not verified) on 26 Mar 2010 #permalink

@fireman: The Hótel Rangá people will probably have all the info you need but here are yet more organized daytours:

The glacier itself is off limits and so is Ãórsmörk. Apparently there's still some concern that a fissure will open under the ice sheet in which case the Ãórsmörk area will be flooded. Besides, the lava flow is slowly headed that way.

Fimmvörðuháls is off limits for motorized vehicles, because of the mud as I understand it. But hikers are free to go up there at their own risk.

The newest concern is the poisonous gasses, especially if the weather is still.

According to the weather forecast it's going to be clear skies for the next few days with winds in the 8-12m per second range.

Hi, I am just an interested observer of volcanoes. Been following this very closely. This blog and comments are really useful.

I just assumed that most people had seen the following site but incase you havent i find it really useful. It is the Icelandic Met Office site, which covers earthquakes. Showing all the latest activity.

You can click on Mýrdalsjökull for a close up. I am watching for activity in Kafla.

@Bruce & Phillip, the lava has not yet reached the cliff. Interestingly enough, the first lava flow seems to be still active as well, generating a conspicuous steam plume further left.
Thanks to all for showing the trick for finding the previous images - though now they're all still images ?!? The webcams at continue to provide streaming video.

Staff from MÃla is actually setting up another webcam on the glacier, about 2km away from the eruption crater. It should go live later today (it should already yesterday, but the cam was broken). The distance to the camera on Thórólsfell is about 12km, Vodafone is a little bit closer to the scene.

A new aerial photo is available on the title page of, which does actually show the new lava flow and a thin dark streak that has already extended down the cliff - not clear if that's the new lava flow (that would be a first surge that has already stopped) or just a trace of hot water that has gone down the cliff.

@ Henrik 99 Yes once I had estimated the size and speed of the bolus it was too small at 0.001% of the crust mass to distort it. So addition of pressure and heat at 20km depth, and infiltration as you propose would be the preferred mechanism for EQspike generation. So bouncing blob or oscillating crust is dead. It would be nice to have seen EQs below 10km. I dont know if the seismometer network senses that deep- if there is a technical explanation for no EQs below 10km that would be useful.

By Peter Cobbold (not verified) on 26 Mar 2010 #permalink

@Henrik 99 I dont agree with heat propagating upwards from a bolus of newly arrived magma - too slow to explain kinetics of the spikes. Rather I see the heat and pressure from the bolus immediately after impact opening up weak points (fractures?) in the immediate overlying crust, allowing propagation of fracturing to progress upwards rapidly, as a fast as the rising phase of the spike- a few hours. Clearly we need to know what state the crust is in at 20km depth, especially in relation to the state of the bolus (temperatures in particular).

By Peter Cobbold (not verified) on 26 Mar 2010 #permalink

@Peter, Henrik, I am really looking forward to see what papers get published on this. I like your Marigold theory Henrik, particularly as you elucidated it in post #86, but I still don't feel it can quite explain the periodicty in either the EQ swarms or the GPS readings, well at least not very well.

I quite agree that a magma pulse would lose energy as it rises and would stall. But what is the feedback loop to set off the rise of another pulse, particularly at such regular intervals? And if the GPS oscilations don't match the periodicity of the swarms, what on earth (sic) are they expressing?

By bruce stout (not verified) on 26 Mar 2010 #permalink

Are they really that regular? The last two "pulses" were very different - Wed 18.00 to Thu 15.00 = 21hrs, Thu 20.00 to Fri 10.00 = 14h. Playing Soucel's recording again, I get the impression that the "pulses" varied in length and that a "pulse" was defined by the smoothed peak intensity curve having a resemblance to a bell-curve. Also, there seems to have been several types of activity going on at the same time although there was some type of perceived periodicity to most. I ask myself - is the periodicity observed a real phenomenon or is it a product of our minds trying to make sense of unfamiliar information?

Ha! Good point that last one. ;-) Nevertheless the first ones were pretty reqular, as Peter noted. The last ones weren't for obvious reasons I think, as the magma was nearing the surface and other factors were at play.
Also look at the uplift on the GPS plots again:

Ok, Iceland goes up and down like a yoyo but I think this wave form is quite pronounced leading up to the eruption. Maybe this is just normal behavior and I shouldn't read too much into it.
BTW look at what SKOR (in the rift zone north of Eyjafjalla) has done since the eruption!!

By bruce stout (not verified) on 26 Mar 2010 #permalink

Looks like I lost a post to the moderation tool.

@Henrik - I like that last comment of yours particularly! ;-)
Nevertheless, I think there was a very clear pattern in the first swarms as Peter and others pointed out. That the pattern weakened towards the end is no surprise as the magma neared the surface and other factors were at play.

And have a look at the uplift on the GPS plots again. Maybe this is standard behavior and I shouldn't read too much into it, but there is a definite wave pattern there.

By bruce stout (not verified) on 26 Mar 2010 #permalink

Anything you guys want me to look at specifically, up at the fissure site? Looks like I'll be heading up there this weekend - once, if not twice. Will gladly take photos of anything specific and/or report back.

MODIS is showing two separate hot spots.

@James : mega envy. It all looks so beautiful even on screen that it must be fantastic to see it close up.

The only thing that has been puzzling me a bit is that the alignment of the fissure site seems to break the typical E/W pattern of the local topography. Maybe you could look around to see if there are any other signs of faults or fissures parallel to the new fissure.

Good on you for taking the opportunity to get up there as often as you can. Enjoy it for all of us and take lots of pictures!!

By bruce stout (not verified) on 26 Mar 2010 #permalink

I thought the map released yesterday (?) showed it trending roughly NE-SW, which is what you'd expect. Possibly it was a little more like NNE-SSW but it still didn't seem so unusual.

I'll have a look, though. Not sure how much will be visible from right up close (might be better from the air), but still.

James, take take closeup photos of the adjacent land surface area for us - would like to know what that extruded sill looks like at close range.

If you have or can find a telephoto lens, we would like to see photos of the nearby glacier surface. Looking for signs of intrusion activity, thermal depression indicating cauldron or deep glacier fissure melt.

Is your department taking a portable SO2 detector to obtain some grab fumarolic readings if you are able to get close to the fissure complex?

Here's a page from the Icelandic Met Office that I didn't see on your Wiki. It has various graphs regarding the current event(live), and some leading up to the event on one page.

It's in Icelandic but I think people might find the graphs interresting.


I'll see if I can get in position for that. I think we're heading up in the afternoon/evening so a lot of the photography depends on the availability of daylight.

I'll be taking my 300mm lens so if there is sufficient daylight for glacier shots, I'll try my best to get some.

I'm actually going up there in a journalistic context, but I would imagine gas readings are being taken if possible. I think it's difficult to approach *that* close to the fissure itself due to the fresh lava flows surrounding it (which look pretty high!) but I will again try to confirm this.

This thread has grown so long that I have given up finding the post where someone stated he was following this eruption very closely because he is expecting Katla to erupt at any moment (to disastrous global effect).

Katla has erupted about 4 or 5 times in recorded history (approx. 1100 years). But there have always been intervals between activities in Eyjafjallajökull and eruptions in Katla. I think the shortest interval was something like 2 months and the longest 2 years. So if recorded history is anything to go by Katla is not going to erupt tomorrow or next week or even next year.


Huh? Katla has a much busier eruptive history, typically erupting 2-3 times per century. Not counting the possible tiny eruption in 1999 (following an intrusive event at Eyjafjallajokull, no less), and an 'uncertain eruption' in 1955 that I had honestly never really heard of before, the last certified eruption was in 1918. Therefore it is probably 'overdue', going on time series alone.

Your point on the timing is valid, though. Approximately 18 months passed between the start of the eruptions at Eyjafjallajokull and then Katla in 1821-1823.

@Bruce 119.122 Henrik 120
The bolus concept can embrace spikes of different shape and time-course: different-sized boluses and velocities. Where I think we are really struggling is how to link- temporally- boluses colliding at least 10km below the lowest recorded EQs. Bolus mass at 0.001% of crust rules out a jarring effect on the *entire* mass.
So perhaps a hydraulic process is at work? Maybe if there is a continuous liquid magma network up through the crust's 20km depth we might envisage a hydraulic linkage? That way the boluses' impacts are transmitted through multiple canals/conduits full of liquid magma, moving a much smaller mass of material. We need to find info on the percentage of crust that is liquid. If it were 0.1 % liquid, 99.9% solid then that 0.001% might be more like 1% . A hydraulic mechanism should jarr a mass 100 times greater than itself, by contributing both kinetic energy and buoyancy.There would be no time delay at all in hydraulics (unless you drive a Prius).
Publish? In my area of biology our meanderings would be dismissed as idle speculation based on inadequate data, unsupported by experiment. In geophysics I dont know- not much scope for the experiments 20km down I guess- but I doubt their research community is glued to these pages.
But I do think a web page somewhere might be a neat idea.
(It could also be interseting to append the pertinent comments from these blogs to show how tortuous the scientific method is- more like stumbling in the dark).
Then when more regular spikes appear and the researchers get excited we can can claim precedence!! So is anyone up for analysing old EQ swarms for oscillations? A distributed analysis amongst this community would be fun.

By Peter Cobbold (not verified) on 26 Mar 2010 #permalink

@ James:

You are right, I admit I'm confusing things.

Katla has always been very active. Her last "certified" eruption was in 1918, as you say. Katla is certainly much overdue and there has long been the sense in Iceland that the next Katla eruption will be pretty disastrous.

There was a 0.1km deep 2.8 EQ at 23:05

By Mattias Larsson (not verified) on 26 Mar 2010 #permalink

Of more interest to me right now is the fact that the ultra-rapid GPS station for THEY is showing a slight inflation on yesterday's reading. Whether it's just a little inaccuracy, or the volcano is actually inflating again, is unsure right now. I'm going to try to find out what the data from the two new GPS stations right near the eruption site is saying.

The new lava flow is easily visible in the Vodafone webcam at night - check it out! I couldn't really see it earlier but now it's really obvious.

Fire fountaining looks like it's picked up since earlier, too.

@someone #133 Thanks for the link! I'll add it to the list soon as I have a chance. I've lots of links still to collate, especially of the various videos there are.

@ Pilipp #131, 137. Great time-lapse movies, thank you! When can we look forward to more? I'd love to see one extended through the night!
(Erm..., you don't need to sleep do you? ;) )

@Peter #138 "our meanderings would be dismissed as idle speculation based on inadequate data, unsupported by experiment"

Love the phrasing, but what constitutes science then? I'd say true science is an epiphany derived from "idle speculation" that is open to experimental and/or mathematical proof and falsification, which leads to a better understanding of an observed phenomenon. The rest is just engineering, best left to minds happy to trudge well-known paths amongst well-known vistas. Unfortunately, there is little scope for true science in science today. It's been taken over by technicians. ;)…

Thought you folks might get a kick out of this. Reporting for kids is one thing - ok, you dumb down the information. But most of the article is hilariously wrong. Courtesy of the BBC (CBBC is their childrens' programming branch), who up until this point have also not grasped the concept that this is not sub-glacial, and continue to spell the name of the volcano incorrectly.

"The last volcanic eruption in Iceland happened back in 1821"? Someone tell that to Hekla, and Grimsvotn, and Katla, and Gjalp, and...

And the bit about Myrdalsjokull melting, having a "devastating effect on global water levels", just about made me smash my face on the keyboard.

>In my area of biology our meanderings would be dismissed as idle speculation based on inadequate data, unsupported by experiment.

Correct. You're dabbling in mechanistic conjecture in thermodynamically complex, multi-phasic media rheological that can't possibly be sorted out by the limited data on hand.

Fact: Eyjaf and it's in-line neighbor to the north are among the oldest volcanoes in Iceland.

Fact: With only four historic eruptions, all coupled with Katla eruptions, the evidence suggests (Thor Thordarson eta al) coupling of magmetic migration and activity, with Eyjaf's eruptions being HIGHLY constrained by larger forces acting from above (glacier and Katla episodic radial fissure dyke-sill intrusion loading) and below (deep earth oscillations, of which geolocation, electro- and geomagnetic data proxies are used to assess various temporal rates-of-change patterns and short-term anomalies).

These forces indirectly determine seismic and GPS readings due to matrix locality responses (meaning the local physical and mineral matrix properties and cumulative formation/rupture history also determines stress-strain and geomagnetic responses).

Fact: Eyjaf is the southernmost terrestrial volcano-fissure system and it's very much influenced by maritime climate.

Fact: Global satellite and-sea surface sensor-based global climate models indicate substantial offshore (S Iceland) warming anomaly has strengthened in the past 15 years with concurrent change in salinity, indicating that deep cold currents flow is impeded.

Glacier mass balance measurements indicate that nearly all of Iceland's temporate (wet melt point) glaciers are presently in a recession cycle that started after the end of major global cooling event, circa late 1800s.

Eyjaf is purported to have lost as much as 1/3 of it's ice mass in that time, predominantly marginal thinning and outlet glacier mass reductions. This is much more than any other glacier and worrying, for a small glacier at higher elevation than the much-larger and 2-3 times thicker glacier overlying Katla.

Katla is presently in it's third cycle of plumbing development, preliminary (simple) stage.

The warm source feeding Katla also feeds Eyjaf, but because Eyjaf is 'off the main feeder circuit', massed forces from above and below must achieve a critical state before a quasi local (possibly midpoint between the calderas) magma intrusion cycle begins that leads to eventual failure and eruption, first at Eyjaf, then at Katla.

This may be interpreted to indicate that weaker, older rock under Eyjaf is the more susceptible path for magma fissure migration after recent sill intrusions (Katla, mid 2000s) within the interleaved flank fissure systems.

It would follow that once sufficient inflows have massed in this midpoint, the pressure inflection tipping point for failure through interconnected fissures is passed, and Katla then erupts, although the actual failure mechanics are far from clear.

I will say this to our friends at the Institute: there is much more afoot there than a simple eruption event.

@Passerby #147. "Correct. You're dabbling in mechanistic conjecture in thermodynamically complex, multi-phasic media rheological that can't possibly be sorted out by the limited data on hand."

Passerby, are you familiar with cognitive process theories such as Constructivism? What Peter, myself and almost everyone else - our vulcanologists included - are doing is predicted by constructivism. We relate unfamiliar, observed phenomena to familiar and well-understood structures and explanation models in order to advance new logical constructs that explain what we as yet do not understand in order to be able to predict future recurrencies. This, we are genetically programmed to do.

To your ennumeration, may I add that Eyjafjöll and Katla sit on the Mid-Atlantic Ridge above a mantle plume, which only adds to the complexity and fascination?

I'd like to modify our assertation "Fact: With only four historic eruptions, all coupled with Katla eruptions". It is not a fact, it is at present no more than an assumption or a hypothesis. The facts are that Eyjafjöll is known to have erupted four times - 550AD(?), 1612 (date unknown), 1821 and 2010. Source: Of these eruptions, only the 1612 and 1821 SEEM to have been followed by an eruption of Katla while the 550AD(?) eruption was preceeded by Katla 540 AD with the following eruption not until 590 AD:

In response to some of your conclusions, particularly "there is much more afoot there than a simple eruption event" I'd like to ask what proof you have to substantiate this? Can you be certain that similar conditions did not exist during previous eruptions, particluarly the data provided by satellite surveillance?

It may very well turn out that you have nailed it Passerby and subsequent events will prove you correct to the last detail! But you too are guilty of "dabbling in conjecture" same as the rest of us! ;)

I'm looking at the cams and have a question:

What happens if the scoria build-up gets overloaded and landslides down into the fissure?

You skipped the 920AD coupled eruptions. The question mark after the eruption date indicates a degree of uncertainty in the dating, +/- years,

Several recent technical publications by well-respected geologists, refer to these coupled eruption dates and describe the coupling of volcanic activity beneath the complex.

The shallow, atypical Icelandic plume is thought to lie under Vatnajökull.

The Mid_Atlantic Ridge under Iceland is also quite complex and unusual, a reason that I explicitly pointed to primers that discuss local geological history. The Mid Atlantic Rise in Iceland lies above m.s.l., where the Ridge is comparatively thin, displaying asymmetric spreading pattern, with evidence of crustal reworking.

My last remark was explicitly directed to Icelandic Geological Institute. It was not a conclusion and is not up for discussion here.

#parclair (#149) - I think if ever (BIG if) the cone will grow as large as to reach the rim of that gorge, it will be simply its growing base that will start to slide inside, building a talus cone (that is, a cone of rock debris leaning against the wall of the gorge). That will not be a problem except if you're standing at the base of that wall, and that will surely be pretty much prohibited. However, the eruptive vents are and will stay at a safe distance from the gorge, so whatever happens at the gorge will not affect the vents. Certainly it would be something to see the cone grow as large as to overtop the rim of the gorge - already the lava falls are a big show, and I have the impression the Icelanders are really thrilled by them. One headline on one of their newspapers these days read "the lava fall ("hraunfoss") is twice as big as Dettifoss" (the largest waterfall in Iceland).

@Passerby and Henrik - I agree with Henrik that we must be careful about assuming that what we believe does correspond to nature. I think it is a *possibility* but nothing more that this current eruption might be followed by something more serious at Katla. I don't think it's very likely, though. There is a ridiculously great quantity of absurdly closely spaced volcanoes on this planet that are known to act strictly independently - they have different magma chemistries, some produce frequent powerful explosive eruptions and their close neighbors make small phreatic explosions every few hundred years. And then there is Etna - this is a volcano that teaches us a tremendous amount of things about volcano and magma dynamics and their endless complexities. At Etna we have four summit craters, the ditance between them being a few hundred meters, and you can't imagine how independently from each other they behave nearly all the time. Because one produces violent activity does not mean that its neighbor will do so as well. Very often this simply does not happen and we've always been wondering how this is possible. While we don't know the answer it definitely is not only possible, it is nearly the rule. Only very few times have we seen that two, three or even all four summit craters of Etna are ALL affected simultaneously by some massive magma supply (this happened once, in 1998-1999).

I remember in the 1970s there was a lot of talk about Katla being "overdue" (there's no such thing as "overdue" at a volcano because they don't obey to strict time frames as we are accustomed to), and when, after the 1973 Heimaey eruption, Katla remained silent, there was a hypothesis that Heimaey actually caused some pressure relief from Katla or diverted magma away from it, and therefore the next eruption might come much later. I don't know how plausible that might be, but one could also suspect something similar in this case, with as much reason as one might expect Katla to blow now because Eyjafjallajökull does.

Conclusions: yes, it may happen that Katla will follow the current eruption, because it has happened twice in the past. But we know far too little to say this is the rule, and that it will happen this time. As I said before, I'd expect to see some geophysical signals at Katla before she joins the party. I would not place any bet on seeing Katla erupt anytime soon. We're all blinded by that immense seismic swarm before this eruption, but there is NO proportional relationship between the intensity and duration of a seismic swarm and the magnitude of the ensuing eruption. Again, Etna has taught us that much over the years. This one here might very well go into history as a happily small, harmless, though very scenic eruption, much publicized due to the internet age (there wouldn't have been that much talk about it 20 years ago), and nothing more. Of all possible scenarios, this is the most likely one.

Great webcam.
Cars going, helicopters flying by rather frequently.
I bet this will generate a nice income for the locals during next weeks :)

It seems that the recently grown hill to the left of the fire is smoking/boiling, and some small fire fountain is also seen in front of the 'dam'. I wonder if there will be any huge explosion where the current 'dam'/cap will be blown away.

My comment about "idle meanderings... " pertained to biology, where the many layered levels of complexity vastly exceed anything volcanos can throw at us and where innumerable measurements have shown all sorts of oscillations to be commonplace. So a handful of biological oscillations, detected just once, would not be deemed publishable without repeated experimental evidence.
But siesmology /volcanology is different- oscillations of such long period /duration and pattern are unusual. So I sense these oscillations under Eyjaf might well have been the first to be recognised. It's pure luck that a biology prof with several papers in Nature on cell Cai oscillations happened by and spotted them.
The spikes are unusual enough to warrant attempts at explanation. Were it not for my persistence, aided and abetted by Bruce and Henrik in particular, I suspect that these oscillations would already have be forgotten. We must not allow that to happen. I suspect that similar ocillations will have been recorded many times previously, in small numbers (as at Eyjaf)from other Icelandic volcanos and maybe others where recruitment of magma is believed to come from ascending boluses....and ignored as being "too limited data to hand".
If we make enough noise here its just possible that a smart seismologist/volcanologist researcher might get curious.
Or a siemologist will point us to papers showing us the phenomenon old hat and well understood!

By Peter Cobbold (not verified) on 27 Mar 2010 #permalink

If nothing else Professor, we have had a most agreeable exchange of ideas and we're indebted to you for these insights!

@Henrik. Its been fun hasn't it? Pity the spikes have gone away though. Or maybe not, don't want more magma arriving under Eyjaf, not until after August, and then only enough to help the locals benefit from the tourists not to precipitate a catastrophe.

By Peter Cobbold (not verified) on 27 Mar 2010 #permalink

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

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