Commentary By Ron Beasley
Here in the Pacific Northwest we know about volcanoes and volcanic ash. I live about 50 miles from Mt. St. Helens and I was here when it erupted in 1980. A friend of mine was killed in the eruption. It's hard to explain volcanic ash - you had to be there. The wind was blowing away from Portland during the initial eruption so we sere spared the inches and even feet of ash they saw in central Washington. But there were several ash producing events that followed and Portland was not spared. The ash is like gray flour or talcum powder. It gets into everything. It drifts and blows and is stirred up when you walk or drive. It got under the shingles on the roof and I was still cleaning it out of the gutters 4 years after the eruption. The air filter on the car was good for a day or two and there was a serious shortage of them. Air traffic was impacted but the Portland airport being shut down is nothing like Eurpoe being shut down. And St. Helens was a little eruption unlike past eruptions in Iceland. The impact on the airlines may be just the first of many long term adversities.
How an Icelandic volcano helped spark the French Revolution
Just over 200 years ago an Icelandic volcano erupted with catastrophic consequences for weather, agriculture and transport across the northern hemisphere � and helped trigger the French revolution.
The Laki volcanic fissure in southern Iceland erupted over an eight-month period from 8 June 1783 to February 1784, spewing lava and poisonous gases that devastated the island's agriculture, killing much of the livestock. It is estimated that perhapsa quarter of Iceland's population died through the ensuing famine.
Then, as now, there were more wide-ranging impacts. In Norway, the Netherlands, the British Isles, France, Germany, Italy, Spain, in North America and even Egypt, the Laki eruption had its consequences, as the haze of dust and sulphur particles thrown up by the volcano was carried over much of the northern hemisphere.
Ships moored up in many ports, effectively fogbound. Crops were affected as the fall-out from the continuing eruption coincided with an abnormally hot summer. A clergyman, the Rev Sir John Cullum, wrote to the Royal Society that barley crops "became brown and withered � as did the leaves of the oats; the rye had the appearance of being mildewed".
The European famine contributed to the French Revolution although the fact that Louis XIV bankrupt the country to support the American Revolution didn't help.
Airline travel in Europe will probably be disrupted for months if not years but disruption of global weather may be even more problematic.
Update
It would appear to be getting even worse for air travelers in Europe.
Millions of air travellers are stranded as thousands of flights are
being cancelled for a third day.The disruption from the spread
of ash would continue into Sunday, European aviation agency Eurocontrol
said........
The agency, which co-ordinates air traffic control in 38 nations, said
it expected 16,000 flights to be cancelled across Europe on Saturday,
from a total of 22,000 on a normal Saturday.
Airline travel in Europe will probably be disrupted for months if not years but disruption of global weather may be even more problematic.
ReplyDeleteRather overstating the case a little here, aren�t we? Most of the estimates I�ve seen are talking days rather than weeks, and certainly not months or years. The concentrations of ash are only dangerous for two or three days unless the cloud gets further additions from the volcano, and from what I�ve been reading, the eruption and seismic activity is dying down in Iceland, though that can of course change.
Also, the Laki eruption was the second largest in recorded human history after the 1815 Tambora eruption, putting out the same amount of ash as the Mt. St. Helens eruption every three days for the better part of eight months. This eruption isn�t in the same category.
I think the main reason this appears so disruptive is due to the combination of the facts that air travel is far more common now than it was back in the 80�s or 90�s when St. Helens or Pinatubo erupted, and that the ash cloud is smack dab on top of one of the richest,and therefore more heavily air-travelled, parts of the planet. Put the same cloud over the Pacific and you might have a few planes taking longer to get to their destinations because they had to fly around it rather than shutting down whole countries� airspace.
Basically, unless the eruption resumes and grows considerably larger, its long-term effects are likely to be fairly negligible.
BJ, I suggest you read this
ReplyDeleteNow what the picture is concerned about is that generally when Eyjaflallajokull erupts so does Kalta, which is right next door. But Katla is a larger system and the eruption is generally much more severe.
Unfortunately what has also to be considered is that there are a whole line of craters, not shown on this map, between Katla and Vatnajokull, which are also a worry. Laki, an even greater threat than Katla, lies along this line.
Ron, that post is highly speculative to say the least. I mean, I can�t argue that if the Eyjaflallajokull eruption continues, and if it triggers a larger eruption in Kalta, and if that causes something to happen to the Laki system and an even larger eruption, then things are going to be pretty bad for an extended period. However, that is roughly as helpful as saying that if the Big One ever hits the West Coast, it�ll be really bad. True, but not actually predictive of when it will hit in the near future.
ReplyDeleteSo far, the best explanation I�ve seen is the following:
"It is usual that an explosive eruption like this has its most intensive point at the start and that it gradually subsides," he told BBC News.
What scientists are trying to find out, he explained, is if the [ongoing] eruption is explosive enough to create a tall column of ash and continue feeding the plume.
It is the explosion that initially forces the ash upward - expanding gas at the eruption site generates thrust. From there, the cloud of dust and gas rises because it is warmer than the surrounding air.
So if the eruption continues to be intense and explosive, giving the ash that initial upward thrust, the plume that has been blown in UK and European airspace could continue to grow.
But according to the most recent reports from the UK Met Office and the Icelandic Met Service, ash is now being released in pulses rather than a continuous plume.
Professor Davidson said that there was no way to reliably predict how the Eyjafjallajokull volcano will behave.
"This eruption started on 20 March," he said. "So in a sense it's been erupting already for almost a month.
"We will be watching the seismic activity because [from that] we will be able to see the predictions in changes in the behaviour of the volcano that will herald an increase or decrease in its activity."
And currently, there appears to be far less seismic activity in Iceland than in the days running up to Wednesday's eruption. This could mean that the worst is over.
However, there is at least one worrying aspect to what they�re finding in Iceland.
ut researchers in Iceland, who have analysed the first sample of ash produced by the volcano, have found that its composition could contribute to the explosiveness of future eruptions.
"The magma is much richer in silicon than the basalt that was previously erupting in the initial stages," explained Dr Mike Burton, senior volcanologist at the Italian National Institute for Geophysics and Volcanology.
"This has two important implications. Firstly, the ash produced will be finer, with smaller particles compared with basalt."
Finer ash will rise more easily.
Secondly, he said, "the activity may well be more explosive because of the higher viscosity of the magma."
The more viscous the magma, the less easily gas flows through it. "Therefore it's easier for pressure build up to occur, leading to more violent explosions."
So things certainly could get worse at some point, but when that point is could be days or years away. When you say things like �airline travel in Europe will probably be disrupted for months if not years�, you seem to be implying that the worst-case scenario is imminent and a near-certainty when I haven�t seen anything to indicate that it is.