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| -Signs, Portents, and the Weather- | |
| Scientists forecast decades of ash clouds (from Iceland volcanos) | |
| 2010-05-17 | |
| THE Icelandic eruption that has caused misery for air travellers could be part of a surge in volcanic activity that will affect the whole of Europe for decades, scientists have warned. They have reconstructed a timeline of 205 eruptions in Iceland, spanning the past 1,100 years, and found that they occur in regular cycles — with the relatively quiet phase that dominated the past five decades now coming to an end. At least three other big Icelandic volcanoes are building towards an eruption, according to Thor Thordarson, a volcanologist at Edinburgh University. "The frequency of Icelandic eruptions seems to rise and fall in a cycle lasting around 140 years," he said. "In the latter part of the 20th century we were in a low period, but now there is evidence that we could be approaching a peak." His findings coincide with new warnings that the eruption of Eyjafjallajokull, which has disrupted air traffic across Europe for several weeks, could carry on for many months — and possibly years. Some geologists have also warned of a serious threat from a fourth volcano, Katla, which lies 15 miles to the east of Eyjafjallajokull. Two of its past three eruptions seemed to be triggered by those of its smaller neighbour and a report issued just before Eyjafjallajokull blew suggested Katla was "close to failure [eruption]". The three other volcanoes cited by Thordarson as being potentially close to a large eruption are Grimsvotn, Hekla and Askja — all of which are bigger than Eyjafjallajokull. In the past, they have proved devastating. Hekla alone has erupted about 20 times since AD 874, pouring out a total of two cubic miles of lava from a line of fissures that stretches 3A miles across the mountain. There was a minor eruption in 2000 and geologists have reported that snow is once again melting on Hekla's summit, suggesting that magma is rising. Grimsvotn, another highly active volcano, lies under the huge Vatnajokull glacier in Iceland's southeast. An eruption in 1996 saw much of this glacial ice melt, causing a flood that washed away the country's main ring road. It is linked to the massive Laki fissure volcano whose 1783 eruption ejected so much ash into the atmosphere that it cooled the entire northern hemisphere for nearly three years. The resulting low temperatures caused crop failures and famines that killed 2m people and helped trigger the French Revolution. Thordarson believes that the behaviour of the volcanoes is linked to movements in the earth's crust which create massive subterranean stresses over wide areas. As these stresses build up, more volcanoes erupt and as the stress disappears, the volcanoes subside again. The theory is a controversial one. Gillian Foulger, professor of geophysics at Durham University, suggests that historic clusters of eruptions could well have occurred by chance. She said: "This needs rigorous statistical support." However, both she and Thordarson agree that Europe needs to take the threat of further Icelandic eruptions more seriously, including improving the monitoring of active volcanoes. Foulger is writing to David Willetts, the new science minister, suggesting Britain could support Iceland in such a project. She said: "There are about 35 active [big] volcanoes in Iceland and if we put a high quality seismograph and some global positioning equipment on each one we would often be able to tell in advance if an eruption was coming. The cost is tiny compared with the potential economic damage from an unexpected eruption." The most pressing question for Britain and the rest of Europe is how long the current eruption will continue. Professor Stephen Sparks, from the earth sciences department at Bristol University, said: "Every volcano has its own personality. This particular volcano has erupted before in 1612 and 1821. When it erupted in 1821 it continued erupting for 15 months so there is no reason why it could not last a similar period of time." The new rules in place for aviation mean Iceland and Europe can probably cope with Eyjafjallajokull, but an eruption by Katla could cause far bigger problems. Dr Richard Waller, senior lecturer in physical geography at Keele University, believes the ash cloud could be immense, but for Iceland the biggest problem would be massive flooding. Katla has a crater filled with ice more than 2,000ft thick, which will all melt," he said. It's magma reaching ice/water that is the main cause of ash.
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| Posted by:phil_b |
| #7 ...obviously that calls for more grant money. /sarc off |
| Posted by: Procopius2k 2010-05-17 19:21 |
| #6 The irony is that over century timescales we can predict volcanic eruptions with rather more accuracy than changes to the climate. Yet we are completely unprepared for a repeat of the 1783 eruption. |
| Posted by: phil_b 2010-05-17 19:03 |
| #5 Laki's output of sulphur dioxide dwarfs the 1990 eruption of Pinatubo in the Philippines, which is famous for halting global warming for several years. While that eruption produced 17 mega tonnes of sulphur dioxide, Laki was pumping the same amount out every three days at its peak, says Self. He estimates Laki's power was over 100 times greater than the current eruption. "The 1783 eruption pumped out so much sulphur gas, creating a huge cloud of sulphuric acid droplets which began to drift over Europe travelling eastwards over the whole world," he says. The noxious fog travelled down through Norway, Germany, France and across to Britain, causing panic when farm labourers began dropping like flies. People at this time had no idea where the fog had come from or that sulphur dioxide was mixing with water vapour in the lungs to choke victims. Research into parish records has led to estimates of more than 20,000 deaths in Britain alone during the summer of 1783. |
| Posted by: phil_b 2010-05-17 17:15 |
| #4 I'm very much afraid not, John. AGW is bunk. And the earth IS entering a cooling phase. But this high latitude volcanic ash will simply be used by the Goracle to explain away the coming lower temperatures and buildup of arctic ice. Just watch. Those BS artists believe it's heads they win, tails WE lose. |
| Posted by: Omolush de Medici1656 2010-05-17 14:10 |
| #3 Ireland needs to keep an eye out, too. There is some historical evidence that major eruptions in Iceland have created tsunamis that have struck Ireland. |
| Posted by: crosspatch 2010-05-17 13:53 |
| #2 ...And maybe it will derail Al Gore's money-making man-made snake oil global warming |
| Posted by: JohnQC 2010-05-17 10:17 |
| #1 A curse for the airlines & a blessing for surface based shipping. |
| Posted by: Anguper Hupomosing9418 2010-05-17 09:58 |