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-   -   Iceland volcano eruption risk level raised for aviation (https://www.pprune.org/airlines-airports-routes/545915-iceland-volcano-eruption-risk-level-raised-aviation.html)

Nearly There 30th Aug 2014 20:33

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.

Flash2001 30th Aug 2014 20:51

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...

mad_jock 30th Aug 2014 20:58

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.

Old Engineer 31st Aug 2014 04:54

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 :)

mad_jock 31st Aug 2014 07:48

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.

oceancrosser 31st Aug 2014 09:36

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.

AmericanFlyer 31st Aug 2014 12:03

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

Evey_Hammond 31st Aug 2014 12:16

Lovely lava can now be seen here

Bittair3000 31st Aug 2014 13:20

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

nigel osborne 31st Aug 2014 14:16

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.

mad_jock 31st Aug 2014 19:20

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

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

OFSO 31st Aug 2014 19:29

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

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

Evey_Hammond 1st Sep 2014 19:42

Very impressive (ash?) cloud currently live here

mad_jock 1st Sep 2014 20:50

Sulphur dioxide and steam apparantly.

henry_crun 3rd Sep 2014 06:28


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

mad_jock 3rd Sep 2014 07:37

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.

henry_crun 3rd Sep 2014 18:12

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'.

ZOOKER 5th Sep 2014 12:14

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

grebllaw123d 6th Sep 2014 17:49

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

Mesmerizing video of the Holuhraun eruption - mbl.is

henry_crun 9th Sep 2014 07:07

Space in Images - 2014 - 09 - Bardarbunga sulphur dioxide spread


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