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Author Topic: Why has Iceland's glacier erupted ? I thought that they are freezing cold ??  (Read 9503 times)

Offline rosalind dna

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I have heard the news today about Iceland's glacier erupting with volcanic
ash all over Iceland and other Northern European countries including Ireland,
England, Scotland, Wales also Norway, Sweden also Finland's airspace have
all been closed possibly until Saturday or longer because the volcanic ash
is covering the upper air as far as I understand.

What I don't understand is just how can a freezing cold glacier erupt?

It seems totally impossible to my non-scientific mind.

http://en.wikipedia.org/wiki/2010_eruption_of_Eyjafjallaj%C3%B6kull

I wonder if anyone can help please.

Rosalind


 

Offline JimBob

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It isn't the glacier that erupted. It is the volcano under the glacier that erupted. This is causing all of the ash fall problems. The melting of the glacier on top is causing flooding in Iceland.
 

Offline rosalind dna

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Thanks Jimbob, but it's still a mystery to me although I do know that Iceland has a lot of bubbling geysers there.

But it looks the normal spring overcast weather just like it's done for days before this Icelandic volcano erupted. That seems odd to me.
 

Offline Bass

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As JimBob stated, it's the volcano under the ice that erupted.  The whole of Iceland is volcanic- even if it is far enough north to be covered with glaciers.

Iceland sits astride the volcanic rift zone that runs the length of the Atlantic ocean.  This is a divergent margin- meaning that the tectonic plates are pulling away from each other and the Atlantic is slowly growing larger.  The rift zone is where the plates actually pull apart, easily allowing volcanic material to reach the surface.  On top of that, Iceland also sits on a "hotspot"- the lavas that erupt in Iceland probably come from deep in the mantle.

There have been 2 very large Icelandic eruptions in the past ~1000 years, Eldgjá around 935-940 AD and Laki in the 1780's.  Laki, which released large amounts of sulfur dioxide, may be partly to blame for the intensity of the Little Ice Age.
 

Offline rosalind dna

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As JimBob stated, it's the volcano under the ice that erupted.  The whole of Iceland is volcanic- even if it is far enough north to be covered with glaciers.

Iceland sits astride the volcanic rift zone that runs the length of the Atlantic ocean.  This is a divergent margin- meaning that the tectonic plates are pulling away from each other and the Atlantic is slowly growing larger.  The rift zone is where the plates actually pull apart, easily allowing volcanic material to reach the surface.  On top of that, Iceland also sits on a "hotspot"- the lavas that erupt in Iceland probably come from deep in the mantle.

There have been 2 very large Icelandic eruptions in the past ~1000 years, Eldgjá around 935-940 AD and Laki in the 1780's.  Laki, which released large amounts of sulfur dioxide, may be partly to blame for the intensity of the Little Ice Age.

Thanks Bass, I wasn't aware before yesterday just how volcanic Iceland is, but as you said that the Atlantic is growing slowly that might affect the rest of Northern Europe even possibly America??

Which tectonic plates is Iceland on?
But it must dreadful for the Icelandic people now, not knowing whether or not a bigger volcano will explode or not, as predicted.

Yes I think that the sulphur dioxide is in the numerous geysers, I think.

 
 

Offline Bass

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Part of Iceland is on the North American Plate, and part is on the Eurasian Plate.

The good news about these types of volcanoes is that they don't tend to explode since they are basaltic- however, they can expel large volumes of gasses and ash.
 

Offline rosalind dna

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Part of Iceland is on the North American Plate, and part is on the Eurasian Plate.

The good news about these types of volcanoes is that they don't tend to explode since they are basaltic- however, they can expel large volumes of gasses and ash.

Bass, so that's more likely to erode over time than explode.
That's why there are still no flights allowed over Europe and that it
might get as far as Greece by tonight.
But they do melt which could mean that the whole of Iceland would be drowned?
Yes I am probably being over pessimistic
 

Offline Bass

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Rosalind

Remember that not all of Iceland is erupting- only one small vent at present.  So the flood danger is only to those people who live downstream of the glacier where the vent is erupting and melting the ice.  Talked with a friend at Cascade Volcano Observatory today who said the eruption is not abating, rather growing more forceful.  I'm afraid this could impact Europe for quite some time, depending on wind directions.
 

Offline John Chapman

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Believe it or not I've actually missed all the news about Iceland's volcano until today. I've recently been working 15 to 20 hours per day so I have bearly watched TV for weeks. Also, I tend to listen to podcasts at work and so have never bothered to find the codes to get the radio working in my van. So current affairs not presently my strong point. I only found out the US had a new president the other day. I thought Reagan would never leave!

So what I want to know is this. Will the volcano have a net warming or cooling effect on the planet?


[the eruption] Laki in the 1780's, which released large amounts of sulfur dioxide, may be partly to blame for the intensity of the Little Ice Age.


Wasn't it following the creation of ash during the Tunguska Event that the UK had an 18 month winter with Londoners skating on the frozen Thames? But what about all the greenhouse gasses that will presumably be around far longer than the ash? Obviously we can all see the benefit of Wales being buried under ash in a Pompaii style event, but what about long term global warming/cooling?
 
« Last Edit: 18/04/2010 14:03:59 by John Chapman »
 

Offline LeeE

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The current eruption in Iceland is actually pretty small, or at least it is so far, and as long as it doesn't turn into a much bigger eruption it won't have much of an effect on climate.

Wasn't it following the creation of ash during the Tunguska Event that the UK had an 18 month winter with Londoners skating on the frozen Thames?

I'm afraid you've mixed up a few different events from history there  ;)

The Tunguska event (in June 1908) didn't generate any ash; it appears to have been an air-burst explosion (only small fragments of the bolide actually reached the ground) of a meteorite or comet, not an eruption.

The 'Year without Summer', in 1816 was reckoned to be due to the eruption of Tambora in Indonesia, combined with a period of very low solar output.

The Thames Frost Fairs, when the Thames froze over, occurred at the beginning of the 17th century: the first was in 1607.
 

Offline John Chapman

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Thanks for the correction, LeeE,

So the Tambora eruption lead to a nett cooling. My wife tells me there's a second neighbouring Icelandic volcano, much bigger than the first, which is also showing some signs of activity. If the situation becomes a cataclysmic local (and not so local) disaster could it ironically end up in helping to refreeze the icelandic and polar glaciers?
 
 

Offline JimBob

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I doubt it would go that far. Tambora was the largest volcanic eruption in recorded history. The ejecta volume from the eruption is estimated at 160 cubic kilometers of material The current eruption in Iceland is of a relatively small volcano - Nothing like the Tambora eruption.
 

Offline rosalind dna

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Quote
Bass
Remember that not all of Iceland is erupting- only one small vent at present.  So the flood danger is only to those people who live downstream of the glacier where the vent is erupting and melting the ice.  Talked with a friend at Cascade Volcano Observatory today who said the eruption is not abating, rather growing more forceful.  I'm afraid this could impact Europe for quite some time, depending on wind directions.
Thanks Bass, but this volcanic eruption has still affected the Icelandic
people badly, I think. That sounds awful and my youngest brother is stuck
in Germany due to the closed Airspace(s) across the UK and Europe.

I doubt it would go that far. Tambora was the largest volcanic eruption in recorded history. The ejecta volume from the eruption is estimated at 160 cubic kilometers of material The current eruption in Iceland is of a relatively small volcano - Nothing like the Tambora eruption.
Jimbob Thanks but isn't there a possibility of bigger volcano exploding
nearer to the present one?
Although it's causing lots of disruption to businesses, schools even health
things like bone marrow which as far as I can work out is useless after
72 hours.
 

Offline RD

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... bone marrow which as far as I can work out is useless after 72 hours.

Bone marrow can be preserved for years ...

Quote
Harvested bone marrow can be combined with a preservative and frozen to keep the stem cells alive until they are needed. This technique is known as cryopreservation. Stem cells can be cryopreserved for many years.
http://www.cancer.gov/cancertopics/factsheet/Therapy/bone-marrow-transplant
 

Offline frethack

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Just a few facts for the magma heads

The volcano apparently is one of Icelands only stratovolcanos, and does produce semi-violent eruptions.  The magma produced during the eruption in the 1820's was a trachydacite, but this eruption so far has produced trachyandesites.  The working hypothesis as of now is that a deep source (not specified if they mean deep mantle source or just generally "deep"...N-MORB vs. E-MORB...I dunno) injected primitive basalts into the fracture system, underwent fractional crystallization at 10km, then moved upward and began to mix with the trachydacites of the present magma chamber to produce the trachyandesites.  It is expected that it will quiet into a more basaltic eruption. 

Heres the link to the report from the University of Iceland
http://www.earthice.hi.is/Apps/WebObjects/HI.woa/swdocument/1015810/2010-04-19+-+Report+on+magma+chemistry+-+Olgeir+et.al+.pdf
 

Offline rosalind dna

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If the other bigger Icelandic volcano explodes ("blows) would
that destroy the whole Island?
Hope not, of course. Because the cooled lava is a good fertilizer
as I'm aware.

I am learning loads reading this thread, thanks everyone for
your interesting posts.
 

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