Cheers gents, yes that was my understanding, I had been reading another site which was quite heavy going, the -0.6 threw me as from what I'd read this is barely a mouse fart yet it had registered. A disturbance at the monitor/sensor site make sense. Im no expert either as you can probably tell but its a fascinating subject to read and to watch.

They don't use Richter much any more, the flavour of the month is Moment Magnitude. It's pretty close to Richter, though. Both these measure the quake at its origin. Another useful measure is Modified Mercali, it says how much it affects you.

After an excellent landing etc...

I am in the same boat.

Find myself recycling the web page looking at various sized spots and getting excited when they change or there is a big one. Then read something find a wordi don't know and loose a hour learning something more about volcanoes.

Here's a little help on that -0.6 [or -0,6 across the pond] number. It is not an earthquake magnitude. It is actually a measure of whether the volcano that might erupt (Bardadur--sp?) is either swelling up (+) or deflating down (-).

The high, conical (more or less) volcano (capped with a lot of ice) acts like a municipal water tower. It pressurizes the underground caverns and tunnels through which the melted rock flows upward. Typically at a certain age it is more common for the melted rock to find a weakness on the flanks of the central volcano and then discharge at a lower elevation some distance from the top of the volcano. At the moment the discharge is some miles to the NNE through a long passage (or several) to area where a great many old fissures lead to the local surface. This area is quietly steaming right now.

This outlet is being fed by a drop in the melted rock level within the higher volcano itself. That causes the flank of the volcano rim to move inward, and also tilt inward. There are several ways this can be measured, either horizontal movement inward or by an inward tilt, depending on the instruments available and placeable. I am not totally sure what this method here is, but let's just say that in this case two opposite points on the rim are now -0.6 centimeter closer to each other in the last 24 hrs. It will go both ways, and after a while a trend can be seen. The trend can reverse as well. If it's tilt, the -0.6 is some measure of an angle (seconds of arc?).

The melted rock contains water, which will flash to steam if enough pressure is removed. Meantime, the steam pressure of the heated water both assists the quartz fraction of the rock to melt and propels the hot slurry through the underground tunnels (sizes in the usual sense of tunnel as we use it). The earthquakes are lurches as the heavy melted rock moves, for the most part, altho their exact nature is not totally understood.

The Icelandic Meteorologic Office has some papers and reports on these subjects on their user-friendly website, in English as well as Icelandic. The key thing here for aircraft, however, is that the Icelanders really watch this stuff, and since 2010, appear also to have upgraded their ability to quickly detect conditions which would be a danger. Hawaii Volcanoes Observatory is also another source of info, altho their excellent commentator has retired (it was a lot of work, some of which he donated).

As for trouble reading all the jargon used, don't feel bad. I was once a geologist, and I know what you're saying. Like the 0.6-- I didn't worry if it was millimeters or meters or angles. It's only whether it's plus or minus and what that means that matters. So long as you've seen it all before, it's ok... ...if not, run :)

jus catching up on the over night activity.

The readings are going to be out for a while as they have a pretty bad storm going through.

And thy seem to have a third area of activity started.

No its at the fissure where it was a few days ago. Appears a little more powerful, but hard to see due to lousy weather.

UPDATE 2-New fissure eruption at Iceland volcano prompts highest aviation warning
 

Lovely lava can now be seen here

More photos can be seen here;
Amazing photos from the eruption - mbl.is

5.1 and 3.2 quakes lunch time Sun 31/8/14 north rim again. Wonder how much more this area can take before it cracks open ?

Interesting comments from Insurance companies saying as this eruption is being so carefully monitored and alerts being raised and reduced...if there is a large eruption they might not treat as act of god,and may refuse to pay out if flights disrupted.

Thankfully none of the reports from the experts I have read in last few days suggest anything other than mild eruptions continuing, perhaps for months.

http://baering.github.io/earthquakes/visualization.html

Have a play with that. That chap is quite talented I think.

Warning
Fissure eruption in Holuhraun (north of Vatnajökull).
Lava exit fissue estimated at 4Km long

Related topics | Earthquakes - all regions | Seismicity | Icelandic Meteorological office

Very impressive (ash?) cloud currently live here

Sulphur dioxide and steam apparantly.

Not sub-glacial, it's coming up from uniced land.

The main volcano still has some activity going on so the sub glacial stuff is not out of the question yet.

They have had a 5.4, 4.9 and 3.8 in the last 24hours.

There is a bot of me wanting a big one, and there is another bit of me doesn't.

Not sure that it is meaningful to compare magma-induced quake figures with tectonic plate quake figures, but a 12.0 might make Californians jealous. I've ridden a 5.8 and it ain't nuthin'.

The webcam is now showing some equipment being set up in front of it.

A fantastic video may be seen via this link from the Icelandic newspaper mbl:

Mesmerizing video of the Holuhraun eruption - mbl.is

The sulphur spread animation didn't show the cloud that went over UK/Ireland over the last few days.

The peaks were most impressive at Ennis and Dublin, but even the North Kensington monitor shot up between 9pm and 11pm on Sunday night reaching an unusual 31ug/m3 at 9.45.

There seem to be hints that an eruption under the glacier (ash ?) may be imminent.

it depends who you look at their opinion.

The government sources are being none committal and are protecting the population as much as the can from themselves but the gas seems to be getting a bit much in some areas.

The gifted amateurs are commenting on the huge dropping of the caldera and there seems to be mixed ideas what this means as every time there is a drop off in activity it drops and starts again. They are say the top mass of the caldera maybe so soft now it doesn't create quakes when it moves.

The one they seem to be most worried about is the main caldera going with 850m of ice on the top of it. And opinions vary between 60%-95% if its going to go.

Just now they are reporting there maybe a small eruption under the glacier but there has been no flood water yet.

http://www.jonfr.com/volcano/

Just been updated, he seems to be a gifted keen amateur and has been pretty spot on so far.

Check that link again. It seems like things are getting serious again with 1 meter drops in the caldera daily.

Might be air closure time again if the winds in the wrong direction. BUt it could be tomorrow or in a months time.

Noticed MET1 on Wednesday over N.Ireland doing several sweeps at FL180 from Fermanagh right up over the north coast.

Anyone know if it was Volcano related?

RÚV

Well the Icelandic media have started propagating emergency LW frequency's for an emergency. Looks like they are gearing up for a big one.

The 850m thick ice cap over the caldera is now showing fissures.

Mad Jock,

There has been a significant drop in the number of earthquakes last few days and their have been none over Mag 4 for a day now.

Could it be that the scientists first likely scenerio has proved to be right, that it is about to stop ?.

However this volcano has defied everyone so far and understanding of volcanoes has had the rule book ripped up, doing things never observed before.

So it may still have a sting in the tail left over the coming weeks.


Nigel

Nigel there was a 4.9 one 12 hours ago in the Caldera.

The stuff I have been reading says the they reckon there is that much movement now inside the crater over 21 meters subsidence that the ground is that soft that it doesn't create shakes anymore. And its dropping at 08. to 1m per day.

The volcano is inflating, the amount of magma coming out of the eruptions so far is less than they reckon is going into it.

850m worth of ICE on top of the thing is now showing cracks on the top because the bottom has dropped so much.

From what I have read is the ice is acting like a champagne cork and once the magma gets at the ice and melts it the reduction of the weight off the top will let it go pop.

http://www.ruv.is/frett/subsidence-b...eters-possible

Well I am currently on holiday on the right side of the Atlantic (in Canada), so anything that gets me out of my impending mix of late shifts next week will do nicely.

If it goes off I suspect you will be getting the boat home :D

They are talking 3-4 weeks of ash. And a up to 5 years with no summer.

If it really goes up we will all hear it go.

Check out Krakatoa.

if your on it seach on farcebook for "Institute of Earth Sciences"

It has some good stuff on it.

Just a quick explanation for those counting earthquakes - this is not a reliable indicator.

The caldera is dropping at a steady rate. When it encounters an obstruction around its periphery it will progressively add weight to it until it breaks. The magnitude and frequency of quakes is simply a measure of the size and number of obstructions.

We're through the period of maximum gravitation modulation. For Iceland, being so far north, this comes during the summer. Perhaps things will hot up again next June/July.

After a few days of reduced activity things seem to be brewing up again around the main caldera.

Lots of +3 shakes with more than a few high 4's both shallow and deep.

I was reading as well the chemical composition has changed of the magma and it is now from 10k +down.

Good news?
 

From jonfr.is Geology Blog today:

IIRC Krakatoa went bang when water got into the volcano - and the blow-out at Mt St Helen's was made worse by the snow and ice around the dome.........

From the UK National Risk Register of Civil Emergencies (2013) regarding an effusive eruptions as is happening now (Not the future suggested caldera collapse of Bardarbunga)

Health impact is one thing and airspace closure is another. Until there's no ash these are only quesses. How would sulphur affect passengers and the industry in short term? SO2 cloud reportedly reached Germany and Austria today (after reaching Norway and Sweden more than 2 weeks ago) and still noone gives a toss. Besides it is washed out quite easily by rain therefore higher contentration far from Iceland is quite unlikely.

TBSC
 

If the caldera at Bardarbunga collapses as is now expected, then airspace closures could be the least of our worries, the Laki event was estimated to have led to 2m+ deaths world wide as a result of changed world wide weather patterns resulting in drought/famine in Asia and 3 very cold European winters

That's the worst, worst case scenario!

The regular factsheets are worth reading:

The Civil Protection Scientific Advisory Board ? Civil Protection and Emergency Management