If Iceland's air-traffic paralyzing volcanic eruption lastyear seemed catastrophic, just wait for the sequel. That's what some expertsare saying as they nervously watch rumblings beneath a much more powerfulIcelandic volcano — Katla — which could spew an ash cloud dwarfing the 2010eruption that cost airlines $2 billion and drove home how vulnerable modernsociety is to the whims of nature.
Brooding over rugged moss-covered hills on Iceland's southernedge, Katla is a much bigger beast than the nearby Eyjafjallajokul volcano,which chugged ash all over Europe for several weeks in an eruption that localscientist Pall Einarsson describes nonetheless as "small."
Named after an evil troll, Katla has a larger magma chamberthan Eyjafjallajokul's. Its last major eruption in 1918 continued more than amonth, turning day into night, starving crops of sunlight and killing off somelivestock. The eruption melted some of the ice-sheet covering Katla, flooding surroundingfarmlands with a torrent of water that some accounts have said measured as wideas the Amazon.
Now, clusters of small earthquakes are being detected aroundKatla, which means an eruption could be imminent, seismologists say. Theearthquakes have been growing in strength, too. After a long period ofmagnitude 3 tremors, a magnitude 4 quake was detected last week.
"It is definitely showing signs of restlessness,"said Einarsson, a professor of geophysics at the University of Iceland.
Teams of seismologists and geologists at the university aretracking the spike in seismic activity and working with disaster officials toprepare communities near Katla like Vik, a small town of some 300 people thatis flanked by black sand beaches.
Civil defense authorities have been holding regular meetingswith scientists. Disaster officials have also drafted an evacuation plan andset aside temporary housing, but many fear they may have less than an hour toevacuate once the volcano erupts.
Iceland sits on a large volcanic hot spot in the Atlantic'smid-oceanic ridge. Eruptions, common throughout Iceland's history, are oftentriggered by seismic activity when the Earth's plates move and magma from deepunderground pushes its way to the surface.
The longer pressure builds up, the more catastrophic aneruption can be. Records show that Katla usually has a large eruption twice acentury. Since its last eruption was almost exactly 93 years ago, it is longoverdue for another, seismologists say.
Icelanders are getting nervous as they mark the anniversaryof Katla's last blast.
"We've been getting calls recently from peopleconcerned that Katla is about to erupt because it erupted ... in 1918 on Oct.12," said Einar Kjartansson, a geophysicist at the IcelandicMeteorological Office.
"As scientists we don't see that much of a correlationin the date but there is most definitely increased activity. The question iswhether it calms down after this or whether there is an eruption."
The eruption of Laki in 1783 was one of Iceland's deadliest.It freed poisonous gases that turned into smog and floated across the jetstream, killing thousands of people with toxic fumes in the British Islesalone.
As sulfur dioxide was pumped into the atmosphere, cropproduction fell across western Europe because of the smog. Famine spread. Andthe sun reportedly turned a blood-red hue — a phenomenon painted by manyartists of the time. Temperatures in Europe were about 2 degrees Celsius (3.6degrees Fahrenheit) below average.
The winter of 1784 was also reportedly one of the longestand coldest on record in North America, with the Mississippi River freezing inNew Orleans. Scientists believe volcanic ash floating over the Atlantic was afactor.
"Volcanoes can be quite beautiful, but they can alsoobviously be quite destructive," Einarsson says.
Of Iceland's more than 22 volcanoes, seven are active andfour are particularly active — including Katla and Hekla.
Although it doesn't pose the same flood risk as Katlabecause it's not situated beneath an icecap, Hekla is one of Iceland's mostactive volcanoes and sits in the path of most international flight patterns.During the Middle Ages, Icelanders called Hekla the "Gateway toHell," believing that souls were dragged into the fire below.
Like Katla, Hekla is also overdue for a large eruption andcould produce a disruptive and dangerous ash cloud that, in addition todisrupting air travel, could lower overall temperatures across continents byblocking out sunlight for days or weeks.
The capital Reykjavik also sits on a plate boundary but ithasn't seen any eruptions for some 800 years.
Still, one of the plates is showing an uplift, or expansionof the crust, which could mean either that a volcano could be nearing aneruption or there is an increase of geothermal activity. Much of Iceland'sinfrastructure was built during a lull in volcanic activity.
"One of these days that situation will change and wewill definitely see more eruptions close to Reykjavik," Einarsson says.
After the Eyjafjallajokul eruption, Icelandic PresidentOlafur Ragnar Grimsson warned European officials that they should be preparedfor future eruptions, and urged the aviation industry to develop engines thatare less sensitive to ash and a better warning system to gauge the threat posedby volcanic ash.
The aviation industry says there is little that airlines cando to prepare for a future ash cloud because decisions on closing air spacerest with national regulators.
"The issue is what the regulators will allow us to do,and that's down to the precise circumstances of any future eruption," saidDavid Henderson, spokesman for the Brussels-based Association of EuropeanAirlines.
But he said that, despite the fragile state of the airlineindustry at a time of economic crisis, a new ash cloud would be unlikely tocause any airlines to go under. Still, Katla's eruption could provesignificantly larger than last year's, producing a larger ash cloud.
"It would take a closure greater than last May's to putpeople out of business," he said. "Everything depends on themagnitude of the eruption."
There are no plans to change engines or any other parts ofthe airframe because all such components are susceptible to damage fromvolcanic ash.
Any major eruption could also upset Iceland's precariouseconomic situation.
This island nation of some 300,000 is only just starting torecover from the collapse of its economy in 2008, when a massive speculativebubble that built up in the banking sector came crashing down in a foretaste ofthe global financial meltdown that was to ensue.
Meanwhile, many Icelanders remain nonchalant about warningsof a major volcanic eruption. Some are even hopeful that they'll get to see oneof the awe-inspiring spectacles.
And Icelanders know that volcanoes are tied closely to theirlivelihood, at most times more friend than enemy. Without them, Iceland wouldbe stripped of its cheap and valuable energy source — geothermal power, whichcomes from heated water beneath the earth.
Even Iceland's most famous person, singer-songwriter Bjork,has drawn from Iceland's volatile geology for her new album,"Biophilia."
"For me, to connect nature to music is a veryeffortless and natural connection" Bjork, 44, told The Associated Press.
Thorir Kjartansson, who manages a souvenir and wool shop inVik — a town close to the flood path of Katla — says he's been waiting for alarge eruption since he was a teenager. His father, who witnessed the 1918eruption, used to warn him before he set out in his car to look north towardKatla's glacier cap.
Residents say they only had about 20 minutes from thateruption to escape its raging flood waters.
"We've been waiting for it for a long time, and we knowthat it will come one day," he said. "Until then, there's no point inworrying about it."