Around 15-16,000 year ago, planetary warming triggered rapid melting of the glaciers, reducing the load acting on the volcanoes beneath and on the underlying asthenosphere.
By 12,000 years ago unloading was sufficiently advanced to trigger a spectacular response. Over a period of 1500 years or so, the volcanic eruption rate jumped by between 30 and 50 times, before falling back to today's level.
dohboi wrote:I guess some people missed this from the last page of this thread.Around 15-16,000 year ago, planetary warming triggered rapid melting of the glaciers, reducing the load acting on the volcanoes beneath and on the underlying asthenosphere.
By 12,000 years ago unloading was sufficiently advanced to trigger a spectacular response. Over a period of 1500 years or so, the volcanic eruption rate jumped by between 30 and 50 times, before falling back to today's level.
Yes, we don't know whether this particular volcano was partly triggered by melting, but it would not be surprising for future volcanoes to be so triggered, since that has happened before on this very island.
The quote if from Bill McGuire's latest book, Waking the Giant about exactly these kinds of inter-relations: http://en.wikipedia.org/wiki/Bill_McGui ... ologist%29
I think that refers to the rebound from the melting of the km thick glaciers after the last glaciation. The glaciers today are much smaller.dohboi wrote:I guess some people missed this from the last page of this thread.Around 15-16,000 year ago, planetary warming triggered rapid melting of the glaciers, reducing the load acting on the volcanoes beneath and on the underlying asthenosphere.
By 12,000 years ago unloading was sufficiently advanced to trigger a spectacular response. Over a period of 1500 years or so, the volcanic eruption rate jumped by between 30 and 50 times, before falling back to today's level.
Yes, we don't know whether this particular volcano was partly triggered by melting, but it would not be surprising for future volcanoes to be so triggered, since that has happened before on this very island.
dohboi wrote:I think everyone knows that Iceland is on the Mid-Atlantic Ridge.
The point is that the last deglaciation did lead to an unusually large amount of volcanic activity there. The question is whether the same thing will happen as GW melts even more glaciers there.
Irpsit
August 23, 2014 at 22:12
I have a feeling that since every day the dike seems nearer the surface (10km a few days ago, 3km today), that a fissure eruption is going to start in just a couple of days from now.
Also I also see that every passing day the intrusion progresses northeastwards. Today the dike was just 3km away from the edge of the ice cap. At this rate, it will erupt partially outside of the ice cap, in ice-free land.
So my guess now is for a 10km long fissure eruption occuring in 2 days, part explosive/ash, part just lava fountains. Eventually, the tip of the fissure becomes a small shield volcano eruption, around 0.1-0.5 km3. Either that, or we will see this build-up for months and the episode is going to involve much larger volumes of magma, 1-10km3.
THE anticipated eruption of an Icelandic volcano will not have as big an impact on aviation as the ash cloud crisis that struck in the summer of 2010.
As much as €3.5bn was wiped off the value of the global economy back in 2010 as a result of the euruption of the Eyjafjallajokull volcano.
More than 100,000 passenger and freight flights were cancelled as a result of no-fly orders because of fears that an ash cloud that spread from Canada to Siberia would damage aircraft flying through the particles.
The direct cost to the airline sector was around €1.3bn.
Airlines were forced to tear up timetables and wait for the ash to disipate.
But this time around the disruption is likely to be far less, because airlines have adopted a more scientific process to identify dangerous skies.
How much FF was not burned as a result?Graeme wrote:More than 100,000 passenger and freight flights were cancelled as a result of no-fly orders because of fears that an ash cloud that spread from Canada to Siberia would damage aircraft flying through the particles.
The direct cost to the airline sector was around €1.3bn.
http://www.bbc.com/news/world-europe-28917495
Iceland has lowered the warning level to aviation from the Bardarbunga volcano from "red" to "orange", its second-highest level.
However, the Icelandic Met Office said there were "no indications that [seismic] activity is slowing down" and added "an eruption cannot be excluded".
Earlier, two earthquakes shook the area around Bardarbunga.
dohboi wrote:So is the thinking now that nothing much is going to come of this, at least in the short-ish term?
It adds to concerns that magma from Bardarbunga could feed into the nearby Askja volcano.
British and Icelandic scientists say that 50 million cubic metres of molten rock has moved in a 24 hour period.
If it continues to head north, it could link up with the Askja system and trigger a large eruption.
Scientists working in the area have said that they will be withdrawing from the exclusion zone on Wednesday after they have deployed some more instruments.
Prof Bob White, from the University of Cambridge, said "It's headed straight for it."
But he cautioned that volcanoes were hard to predict.
I think it's worse if it's under a glacier.vtsnowedin wrote:If it's fifty million cubic meters of magma does it really matter which chuck hole it pops up out of?
Keith_McClary wrote:I think it's worse if it's under a glacier.vtsnowedin wrote:If it's fifty million cubic meters of magma does it really matter which chuck hole it pops up out of?
Well you wouldn't want to live in a cabin at the foot of the glacier as you might get a lot more hot water then you can handle but compared to the poison gasses that often are thrown out by erupting volcanoes along with the earthquake potential I'd think some fresh water steam would be the least of your worries.WildRose wrote:Keith_McClary wrote:I think it's worse if it's under a glacier.vtsnowedin wrote:If it's fifty million cubic meters of magma does it really matter which chuck hole it pops up out of?
Apparently that's the worst kind of scenario for a disruptive ash cloud, if the eruption comes up through a glacier.
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