The Case for An Imminent, Catastrophic Eruption at Volcano Katla, Iceland

Hey hey , like the thread just wanted to toss in a comment or two, Katla is the name of the volcano in icelandic and english, Mýrdalsjökull is just the name of the glacier in wich katla resides.

Katla was just a alarm becouse of the previus eruptions in history that took place after eyjafjallajökull erupts, that is why the panic began, katla is just 1 of 7 overdue volcano´s in iceland at the moment, 4 of those have had the largest eruptions here in iceland for up to 2 years or longer. The current information shows alot more activity at grímsvötn. Comparing to Vatnajökull at the moment Mýrdalsjökull seems to be sleeping, and most of the activity at mýrdalsjökull is at fimmvörðuháls where the first eruption happent this summer, Katla´s crater has hardly had any quakes. Puterman is correct when he says that Vatnajökull is the place to be watching at the moment becouse of the quake activity there and the number of large volcano´s in that region that are overdue.

10 quakes in a period of 48 hours is nothing to worry about here in iceland, it´s quite normal if you look back through history. Every 7-10 years we get a quake that we named the Suðurlandskjálftinn that is always above 6 on richter. There is no actual evidence at the moment that Katla is going to erupt, not unless we get a huge spike in activity. Those stations have been peeking out all summer from when i started observing them. Im not dismissing the theory , just that at the moment there are other area´s that seem to be alot more active, and we shouldn´t actually be waiting on 1 volcano to erupt, if they are gonna blow im guessing we´ll be getting 2-3 volcano´s blowing off steam.

Originally posted by Spacedman13
Katla´s crater has hardly had any quakes.

Well, just today look:



Quakes inside the rim, and more on the edges!

In 1918 they didn't have the kind of monitoring they have now... So once it does blow, it will give science valuable information for future generations.

reply to post by Spacedman13


Hi Spacedman, I bow to your superior Icelandic knowledge. I was reading an article some time ago that refered to the Icelandic as Kotla (with some accents) and the English as Katla, but I agree that either way this is the volcano and Myrdalsjokull is the ice cap.

Originally posted by TrueAmerican
There is just no way of knowing until it happens.

True, but the potential available volume is massive if the figures are right. A block 7km lomg by 3 km wide by 1 km deep if that helps to visualise. And you are also right that a volcano cannot be classified as VEI anything, VEI refers to an eruption, and can as you say be different every time. Katla has however had VEI 4 eruptions in the past.

What sort of damages will occur when this thing goes? How long will the ash persist? Effects of the flooding?

Again, totally depends on the size of the eruption. Locally, people seem relatively prepared. For one thing, they have avoided population centers around the immediate vicinity of Katla, so there are few people who would die there from the immediate effects, unless the eruption was so big the pyroclastic flows and debris reached beyond the radius expected.

The problem with Katla and any volcano under an icecap is the 'jokullhlaup'

Iceland was buried under ice in the last Ice Age and all eruptions were subglacial. Remnants of the ice caps remain and Iceland continues to have numerous subglacial eruptions. Of the world's known subglacial eruptions, 83% are in Iceland. The most recent eruption, at Grimsvotn, is an example. Subglacial eruptions produce a special type of volcano, called a table mountain or a moberg mountain. Great volumes of meltwater, generated by subglacial eruptions, can burst out from beneath glaciers to produce enormous floods called jokulhlaup. The discharge can be as much as 20 times greater than the flow rate of the Amazon River.
The 1783 eruption at Laki was the largest single historic eruption of basaltic lava (12 cubic km). Recent eruptions include the 1974-1984 eruption at Krafla, a brief eruption at Hekla in 1991 and again on February 26 2000 and three eruptions at Grimsvotn, in 1996, 1998 and 2004.

Source

In Katla´s last eruption in 1918 icebergs the size of houses were seen floating out to sea. More recently in 1955 and 1979 there have been floods though no eruption that you could see.

Source

In the back of my mind I have recollection that the last big one at Katla added 5 km to the coastline. I will see if I can find it.

So PuterMan, would you say these are occurring in the typical locations that indicate that they are part of this summer/winter "refreeze" you mention? Or are they occurring in new locations?

Yes and no. The central conduit is somewhere between the two volcanoes and these particular quakes would seem to be on the conduit. But there have been many in these locations before.

With regard to sensor networks many of these are temporary arrays XD and XE etc, but those on GEE might be the VI network (Icelandic National Digital Seismograph Network ) but there is no information on this that I can find, however I think that is unlikely as VI is the SIL network we can see on the maps (but not get at!! )

The International Federation Of Digital Seismic Networks (FDSN) - A PDF file that indicates that Iceland is a member. Since their goal is to make info available maybe there will be better access soon, but I suspect that we the sheeple are not what they had in mind!

Finally found these on GEE - yes they are obsolete. They are the Torfajokull and other experiments from 2002 and 2005 - temporary arrays.

Sorry, I am going to have to get back to you on the last two points. It is just taking too long to find the data in the 200+ pdf files I have about Iceland.

reply to post by TrueAmerican


Just a quick one. The data presented in that document (which i had) would suggest that actually the Godabunga/Katla inflation was increasing yes, but takes no account of the Eyja eruption (obviously) which I believe halted that inflation. Somewhere in the vast morass of information I recall that the inflation at Godabunga stopped after the Eyja eruption but don't quote me on that - I am looking for the information to confirm this.

reply to post by PuterMan


Interesting...except for one minor problem. If eruptions at Eyja are relieving the stress, then how would it occur that Katla has consistently erupted after Eyja? To me these back to back eruptions suggest otherwise. Had previous Eyja eruptions relieved the stress on Katla in this way, it would have been almost impossible for Katla to erupt right afterwords.

In fact, this very issue may indicate a high level of independent magma chambers- linked due to proximity- but not so linked that the eruption of one relieves the stress of the other.

Also, a public thanks for moderator applause. Occasionally I will put some real work into a thread, and it's nice to be appreciated. On that note, I request that you also applaud PuterMan. He is as much a part of this thread as me, if not more.

reply to post by TrueAmerican


Found one of the items I was looking for:

Between late 2000 and early 2005 there was a moderate increase in seismicity rate beneath Katla caldera, and a much greater increase in seismicity rate in the Goðabunga area, on the west flank of Katla. The increase in seismicity was approximately coincident with upwards and radially outwards movement of two campaign GPS stations north of Katla caldera [7]. This motion has since ceased, but two continuous GPS sites on the southern flank have been trending upwards and south-southwest, after subtraction of plate-spreading motion, since installation in 2000 [8], and this motion continues to the present.

The source for this is: DEFORMATION DUE TO MAGMA MOVEMENT AND ICE UNLOADING AT KATLA VOLCANO, ICELAND, DETECTED BY PERSISTENT SCATTERER INSAR by Andrew Hooper and Rikke Pedersen, Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland but I am afraid I do not have the web link at present.

(Note to Mods: That is the title - all in capitals)

The conclusion in this document is:

We find that there is no significant systematic motion of the flanks of Katla from 1995 to 1998 and from 2000 to 2006, other than that expected from thinning of Vatnajökull and Mýrdalsjökull ice caps. We conclude that increased seismicity in the region of Goðbunga was not accompanied by significant deformation. We also
detect local variations in velocities that may be due to landsliding.

I am still looking for the document that takes this closer to 2010.

Edit:

ABSTRACT. The Katla volcano, overlain by the Myrdalsjokull glacier, is one of the most active and hazardous volcanoes in Iceland. Earthquakes show anomalous magnitude-frequency behaviour and mainly occur in two distinct areas: within the oval caldera and around Goðabunga, a bulge on its western flank. The seismicity differs between the areas; earthquakes in Goðabunga are low frequency and shallow whereas those beneath the caldera occur at greater depths and are volcano-tectonic. The seismicity shows seasonal variations but the rates peak at different times in the two areas. A snow budget model, which gives an estimate of the glacial loading, shows good correlation with seismic activity on an annual scale. Data recorded by the permanent network South Iceland Lowland (SIL), as well as by a temporary network, are used to invert for a 3D seismic velocity model underneath Eyjafjallajokull, Goðabunga and the Katla caldera. The tomography resolves a 15 km wide, aseismic, high-velocity structure at a depth of more than 4 km between the Eyjafjallajokull volcano in the west and the Katla volcano in the east. Anomalously low velocities are observed beneath the Katla caldera, which is interpreted as being a significantly fractured area of anomalously high temperature.

Source: Habits of a glacier-covered volcano: Seismicity patterns and velocity structure of Katla volcano, Iceland

This is a 2007 document.

On page 4 .......

consistent with the visual observation that the Goðabunga seismicity has a maximum in October and the snow budget a minimum in September

Well dang me and ain't we jist in October now!

Yes in my opinion activity is within normal parameter bounds. There are also references in this document to the inflation rates of around 12 mm so the balance mat be unloading.

I am still looking for a document a young lady did for her doctorate thesis that sheds some light on all this.

Want to learn Icelandic?

Originally posted by TrueAmerican

Originally posted by Spacedman13
Katla´s crater has hardly had any quakes.

Well, just today look:



Quakes inside the rim, and more on the edges!

In 1918 they didn't have the kind of monitoring they have now... So once it does blow, it will give science valuable information for future generations.

This is actually just minor activity, 2 small quakes outside and inside the rim, the area woke up back in 2002 and has been active since that time, there are only about 5-6 weeks inbetween there that there where no quakes in the area.

I like the theory about how Iceland is constantly shaking and regarding how the plume could be affecting it.
I sometimes find myself shaking without any couse

reply to post by TrueAmerican

Some volcanoes may be so closely spaced that they are coupled; activity in one system has a profound influence on the other. One such pair includes the Katla and Eyjafjallajökull volcanoes

Source

I have more on this somewhere and a schematic of the two. I will post when I find it.

Found that thing about the beach. Not the one I looked at originally which I am sure said 5km. This one says 2km

Mr Kjartansson says that the flooding is also considered to have brought a 2,000-ton rock from the volcano to the black volcanic desert of Mýrdalssandur, while also extending the beach by a factor of 2km within the first 24 hours of the 1918 eruption.

Source

reply to post by Spacedman13


You posted as I was preparing this!!

[atsimg]http://files.abovetopsecret.com/images/member/751c09e8bbf0.png[/atsimg]

I don't like quakes in that area. Not good.

I'm not too deep into volcanology so don't take my words to heart, but perhaps the harmonic tremor from one volcano causes a weakening in the rock of the sister?

If the two volcanoes arent linked by magma conduits, perhaps their tremors set each other off. This could be the reason Katla goes off after Elyji. Since Katla is more active its magma chamber fills up faster and goes off a couple times before Elyji can erupt again. However when Elyji IS ready to erupt, Katla has refilled with magma and has begun inflation and seismic activity, so when Elyji finally blows its top the vibration weakens the rocks keeping Kalta contained and accelerates its eruption.....of course this is just a hypothesis

PuterMan, quick question for you:

How would you characterize Iceland's warning capabilities before Eyja erupted? In other words, did eruption occur as expected, or did it come as a surprise? Were they able to warn residents, predict the eruption, or come close? I am finding all sorts of stuff about Eyja's eruption starting and after March 20, 2010 but it's before that- in fact the three week period before that I can't seem to find much on.

I am very curious about this as it applies to Katla.

In regards to the high velocity structure found (tomography) between the two volcanoes, Eyja and Katla, would that not indicate a high level of independence?

Originally posted by TrueAmerican
PuterMan, quick question for you:

Trick question - oh no I read that wrong.

How would you characterize Iceland's warning capabilities before Eyja erupted? In other words, did eruption occur as expected, or did it come as a surprise?

From what I can gather they knew about a month before hand - this is going from memory. Let's face it they are not going to go spouting off about Katla UNLESS they are pretty damn sure it is going to blow so, if you hear nothing - that is good. If they start saying it is going - duck! (Well at least here in Ireland)

In regards to the high velocity structure found (tomography) between the two volcanoes, Eyja and Katla, would that not indicate a high level of independence?

Surely this indicates the presence of a connection if the tomography found high velocity areas between the two. (Pipes, chimneys etc) Or do I have that the wrong way round?

reply to post by PuterMan


I don't suppose you could be more specific about the degree to which they were able to warn people? I have been trying to find stuff on that...

High velocity areas are usually dense rock, and don't slow seismic waves that much- that's why they are called high velocity. From your post above they say they found through tomography a 15km area between the two, aseismic- meaning it does not produce earthquakes. But it sure will transmit them.

Their tomography also showed a higher temperature area (slows seismic waves, and can be magma) directly underneath the Katla crater.

So my point was that this would tend to corroborate (somewhat) each volcano's independence from the other- if their tomography interpretation is correct.

If I had to guess, I think they are partly right. In fact, one picture I just saw in a scientific document had the two volcanoes drawn in cross section, but it did not show any connection underneath at all, as if they were not sharing magma from one deep chamber in any way.

reply to post by TrueAmerican


Yes of course, old pipes/chimneys, i.e.not molten.

But then if this is the case and there is no connection between the two, my supposition that the connection is anecdotal would possibly be correct?

Sorry forgot to answer the first part. No, all I recall is that the geologists were talking about it, but i don't think any warnings were given.

Originally posted by PuterMan
reply to post by TrueAmerican

 

Sorry forgot to answer the first part. No, all I recall is that the geologists were talking about it, but i don't think any warnings were given.

edit on 5/10/2010 by PuterMan because: (no reason given)

If my memory serves me - we cover the whole beginning of the eljaxyz eruption on the volcano watch thread - then when the eruption finally really started we went to the eljaxyz eruption thread. We had a number of Icelanders there giving up "on the ground' reports of the situation - maybe that would be the place to post to get the information from the locals on the warning they got there - then give the link to here

PuterMan and Anmarie,

Thanks. Now see, that's what I was afraid of, and suspected they couldn't really give much of a warning. They sit there and watch seismicity increase, GPS stations move all over the place, InSaR showing heat increases, and so why in the world wouldn't they give a warning? They lucked out that Eyja had a very small eruption first on March 20. The VEI 4 didn't happen until April 13th.

So the point is that how can the locals depend on them about Katla? That's a much bigger ice layer on Katla. So I guess they must be waiting for the flooding (from heat melting the ice) to start before they freak out?

Check this out from today. That quake is right dead center in the crater on Katla:

And we better hope to God the following isn't what's REALLY going on:





That's a seismicity map of Iceland from 1994-2007, from here:

www.vedur.is...

I have drawn the big green circle on it, to suggest a possible Mega Caldera, partially hidden. Now I know that's a pretty big stretch, but if it were true, at over 400 km long that would qualify for one of the biggest (if not the biggest) caldera on Earth. The Yellowstone caldera is only 55km or so long by comparison.

Could it be that the Iceland volcanoes are only the surface vents for something much bigger they cannot entirely see?

reply to post by TrueAmerican


Ehhhhh, i really don´t even know what to say to that. Largest caldera on earth is 120km as far as i know of, but the picture you put up there is,,, 400km wide caldera under the whole country without any kind of evidence and nothing to support it. I just gotta say you are shooting blanks here mate.

Im all for a good theory and all but this one seems to be wayyyyyyy out there man.

Enjoy this picture that should put it into some perspective for you

[atsimg]http://files.abovetopsecret.com/images/member/7b25ad8983ae.jpg[/atsimg]

2 more quakes on the rim of the Katla crater:

en.vedur.is...