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Message Subject The monsters wakes up ! Katla Hekla Iceland Dead Zone and rift as uniform system ! A lot of others worldwide !

Poster Handle Anonymous Coward

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[link to www.wired.com]
a320er • 2 hours ago −
What are the chances that Etna could go explosive? Could that ever happen?
good question

excellent answer on this good question :
[link to www.wired.com]

Boris Behncke a320er • 3 hours ago −
Etna has had powerful explosive eruptions in the past (including a Plinian eruption in 122 B.C.) - and also the lava fountaining episodes in these days are rather explosive (last night's paroxysm led to massive pyroclastic fallout over Etna's northeast flank). The reason for this unusually high explosivity (for a basaltic volcano) is the enormous quantity of water vapor in the magma.

very informative and important continuation
[link to www.wired.com]
"...What is most intriguing about the recent activity, is that it is much more explosive than what has been seen at Etna in the past few centuries. This is probably because more magma is rising faster to the surface, and thus less gas is lost from the magma (foremost water vapor, which makes eruptions explosive). We've seen many similar episodes of lava fountaining at Etna over the years - actually, when I first visited Etna in September 1989, it was making lava fountains twice per day, for about one week - but many have not been as violent as these latest ones. During last night's lava fountain, the entire northeastern flank of Etna was buried under a sheet of glowing pyroclastic material; there are a few spectacular photos circulating, which I hopefully can include in the forthcoming INGV-Osservatorio Etneo report on this lava fountain ..."

Let's try to continue and develop that said above recognized and probably the most authoritative expert on Etna.

What does he say about the reasons why the magma was more water and respectively gas?

He says, "probably because the magma more and she quickly rises to the surface."

Maybe so, but look - he does not approve it definitely.

Why? Because there may be other reasons.

Remember that Etna is exactly at the junction area of the European and African plates?
And if the increase is caused by magma coming acceleration of subduction, and the increase in emissions due to the arrival with the top of the large volumes of sea water (which, by the way - this is well known - is a good "lubricant" during tectonic movements)?

Another option - the formation of new cracks in the crust itself around the magma reservoir, which also received a large amount of water (remember quite recently the great flood in Sicily)?

Need to explain how explosive these options?

He said with authority:
"but many have not been as violent as these latest ones"

We are also in this topic many times marked -

paroxysms start explosively and without warning -
there are no early symptoms
such as gradual growth of tremor or amplification of seismic -
only that it was quiet and then suddenly jump up!

Was it before?
it's not that expert says, but I think not.
And this is the main danger:
Etna becomes unpredictable

Quoting: Anonymous Coward 35734840

and what they would like to continue to deal with what is really going on with Etna.

Thus, the expert says that the magma unusually high water and gas.

A mixture of magma, gas, steam and water under high pressure is released from the crater and we will eventually see those fountains that this year we have already seen seven times.

If the magma is on its way to the surface of the solid volumes of water encountered, the front of the fountain would be observed powerful, explosive character emissions pillars water-gas mixture, but it was not.
Hence, the magma towards the surface of the water encountered in any large cavities within the body of the mountain. In these cavities occurs first boiling water after contact with magma, forming a mixture of magma, water and steam (from now on, that is, from the time of the meeting of magma with water, and was observed repeatedly noted here, "explosive" growth of tremor), and then thrown out of the fountains of that mixture.

What else unusual about the last paroxysms and that we should pay attention to?
This is something that is large pieces of pumice deposited in surroundings (above is a video recorded by the residents of Etna's surroundings where they collect such pieces in their balconies, and a video of an unusually large pieces on the roads).
If volume of such big pices was few, one would assume the launching recently deposited volcanic material only from the outside of the cones.
Since such large pieces apparently had many large areas, it means rising and dispersing a large amount of such material. So it is clearly mainly a material from inner parts of cones was torn off by explosive mixing magma with the water in the aforementioned voids.
Accordingly, it had to increase the volume of these voids within the body of the mountain.
Another consequence of the explosive nature of the magma mixing with the water inside the cavities may well become formation of new cracks and correspondingly increase the flow of water into these cavities with each new paroxysm.

of course, all this is to a large extent only reasoning not supported by any geophysical data (hope that they will soon be made)... but i guess in general the picture is about painted above. that is really Etna becomes more and more dangerous...

Quoting: Anonymous Coward 35790765

calm now...

Quoting: Anonymous Coward 35790765

interesting chart of tremor between 13 nad 17 UTC today
[link to www.ct.ingv.it]

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