Rumblings from another Icelandic volcano

[GloriaSmud]

and it's a big 'un!
This time at Bárðarbunga, with over 200 earthquakes recorded so far and last night, the Icelandic Met Office raised the aviation colour code to yellow to reflect the unrest that's going on.

OYBBK, have you got form for your dreams coming to fruition? That would be quite something!

This is all completely new to me, but absolutely fascinating.

Thanks for the updates.

OhYouBadBadKrillitane Thu 28-Aug-14 08:25:45
Last night I dreamt it had a Krakatoa style eruption so loud that we could hear it in the UK. Pretty sure that won't be an outcome

Spooky. So did I!

Hello everyone.

Gloriasmud, this is a great thread. I must admit I am trying to follow all the goings on, but really don't have a clue. The language is very confusing. I have had a few minutes this morning to try and learn a bit more about it all and found the following, which i found really helpful, so am posting the link in case anyone else might find it useful.

definitions with pics

I love the idea of a Hollywood disaster movie type mission.

What I love more is this is a reminder of just how amazing and unpredictable Mother Nature is and can be.

I have been following the weather posts on here for a few years and this is another fascinating subject that I also don't really understand.

No matter what happens, with this activity, Iceland and it's geology is a new love of mine now, thanks to you all, and of course the promise of Bruce willis in a vest shouting yippee key yayyyyy m... F... As he descends into the pit of the volcano in bare feet

Just a quick question. How do the scientist know that this massive underground movement is happening? I can't quite figure it out. I also found this pic. which shows how the earthquake activity has moved. It's truly amazing!

Thanks again.
Xxx

Kye yayyyy, obviously. Key yayy just doesn't do it for me!

Oh weird RTB!! I wonder if there was a really loud 'boom' that filtered into our dreams - we'd have to live near each other though.

Fortunately not Iwish as I tend to dream about tornadoes quite a lot!

dh has access to lots of aviation info and hes copied me into some info (that is sadly behind a paywall)

Basically there will no longer be blanket bans. Instead there will be an ash risk zoning system issued by VAAC. They will advise not to fly into visible ash or in cloud or dark where ash may be present but not visible. It will be up to airlines what they do with the information and they will be deemed responsible for what happens.

The airlines will be encouraged only to enter a medium or high density ash contamination zone if they have done a risk assessment which will include data from the airframe and engine manufacturers. The article notes that the manufacturers may be reluctant to give such data.

Article notes that the VAAC advisories during Eyjafjallajökull were very accurate in terms of lateral distribution, but not so accurate in terms of height. Prototype hardware is being developed to help pilots see ash clouds on their displays.

Newbie, nice to have you on the thread :)

They are plotting the movement by earthquakes, not just the big ones but all of the microquakes. Its not only that the earthquakes are occurring but the direction of seismic waves and also the type of the waves that are an indicator.

They also have gps sensors on the ground and these show movement up and down and also sideways.

I found a nice website that illustrates a lot of this and other volcano stuff IRIS

Thanks for the welcome Kitten. I've been following it from the beginning. :)

Thanks for the link. I'm going to have a look at that now.

Xxx

That is brilliant OYBBK. Thanks again!
Xxx

Thanks for the links - been watching with interest. We were walking on the south part of Vatnajokull at the beginning of the month - so it all feels a bit familiar.

You are welcome :)

We are going to have the added complication of the remnants of hurricane Cristobel forming a rather nasty deep low and hitting Iceland early next week. It's going to be much harder for scientists to keep a physical eye on what is going on.

28th August 2014 12:35 - from of the Scientific Advisory Board
Scientists from the Icelandic Meteorological Office and the Institute of Earth Sciences, together with representatives of the Civil Protection in Iceland, met today to discuss the on-going unrest at the Bárðarbunga volcano.

Conclusions of the Scientific Advisory Board:
This morning, there was a flight over the Bárðarbunga area and the surface of the glacier was surveyed. No changes to the ice crevasses southeast of Bárðarbunga, that were seen yesterday evening, were observed. These crevasses were likely formed due to melting at the ice bottom.

The depressions have been located southeast of the Bárðarbunga caldera, in all likelihood within the water divide of the river Jökulsá á Fjöllum. There are three circular crevasse formations, about 5 km in total length. The ice thickness in the area is 400-600 m.

The water level in Grímsvötn Lake has been surveyed and has likely risen by about 5-10 m in the last days, which corresponds to an addition of 10-30 million m3 of water in the lake. A slight increase in conductivity in Köldukvísl River was measured this morning, but the cause is yet unknown. No change has been measured in the Hágöngulón lagoon, Jökulsá River and Skjálfandi River. It is assumed, that the water from the cauldron has flowed into the Grímsvötn Lake or the river Jökulsá á Fjöllum.

The seismic activity is similar to that of the last days. Around midnight, three earthquakes of magnitude around 4 were recorded and one of magnitude 5 at 08:13 this morning, all located within the Bárðarbunga caldera.

Shortly before 08:00 this morning, there was a slight increase in seismic activity in the Askja volcano. Changes in the stress field due to expansion caused by the dyke have an effect on the Askja area.

Since yesterday, the length of the dyke under Dyngjujökull has increased by 1-1.5 km to the north, which is considerably less than in the last days. The dyke has now reached the fissure system of the Askja volcano and GPS measurements indicate that the area there is greatly affected.

OK, who put an ancient Chinese curse on the Icelandic people?

So to summarise, perhaps a small eruption underway at Bárðarbunga and the dyke intrusion to the north has slowed considerably but it is making Askja grumpy.

Interesting. thanks RTB :)

Askja is now on a yellow.

Yes, OYBBK

Plus, with water draining towards Grímsvötn Lake it suggests the water is going south rather than north, so is more likely to affect the ring road in the south rather than the areas currently evacuated in the central area of iceland.

In 1996 there was a big flood as a result of glacial melt from Grímsvötn Lake which took out a large section of the road - it took several weeks after the eruption for it to flood. They monitored it and closed the road later so no one was caught up in it.

We travelled through there some years ago - there are still pieces of the old bridges there, which you can stop at and look at, which show the huge force of the flooding.

Article about the 1996 flood

We watched a video on that at a visitor centre. It was awe inspiring. They got a temporary through road going so quickly. They have amazing engineers.

Does that report really say the lake level has risen by 5-10 METRES?

And that 10-30 million cubic litres are the reason?

Those numbers are hard to imagine.

So are these lakes quite low down, or does this mean there' sa serious problem with flooding now in the area?

Thanks

Sorry, just read the later posts.

When we had all that rain and flooding last year, it didn't seem to take much in terms of levels increasing for there to be huge problems for so many people. It's a scary thought what might happen there.

Any thoughts/ideas what would cause the dyke intrusion to slow?

Newbiecrafter 5 - 10 metres isn't a large amount compared to previous floods. (Though some reports are saying its 15 metres).

The 1996 flood, was sparked by a rise of 60 meters over the lakes 'trigger point'. So it depends on how full the lake was previously (once the lake overflows the whole system resets and gradually starts to build up again).

There have been jökulhlaups from Grímsvötn Lake in 1954, 1960, 1965, 1972, 1976, 1982, 1983, 1986, 1991 and 1996 from what I can google, but that was the last one.

I would have though that a dyke intrusion might slow, if there had been an eruption which caused this glacial melt as it would release some of the pressure that had been fuelling it. But thats pure speculation as I'm a sofa volcano watcher and nothing more.

Blog by Jón Frímann
"The area is full of old dykes that have cooled into granite type of rock (and other hard types of rock) in the crust (this is a volcano area and I find this to be likely). Given the density and how hard granite is I find it unlikely that this magma is going to break it. It has been crossing softer rock in the crust for the past week."

So if Jón is right, then the slowdown may be caused by a change in the rock type that the magma needs to go through.

Looking at the last 6 hours of quakes using 3dBulge, the location map seems as though it may show a move in the NNE direction.

May be nothing, just how quakes are plotting on the map, but maybe the magma has found a path of lesser resistance.

Jon Frimann says in his latest blog post that the "dyke from Bárðarbunga volcano has entered Askja volcano. Not the fissure swarm, the volcano it self." "I am now close to 80% sure that an eruption is going to take place in both Askja volcano and Bárðarbunga volcano"

Thanks for the explanations.

I'm still sitting here a bit confuddled by all the numbers.

Read his latest update he reckons the magma is now in Askja and we are going to get a double eruption soon.

I wonder how accurate he tends to be.