Brooding over rugged moss-covered hills on Iceland’s southern edge, Katla is a much bigger beast than the nearby Eyjafjallajokul volcano, which chugged ash all over Europe for several weeks in an eruption that local scientist Pall Einarsson describes nonetheless as “small.”
Named after an evil troll, Katla has a larger magma chamber than Eyjafjallajokul’s. Its last major eruption in 1918 continued more than a month, turning day into night, starving crops of sunlight and killing off some livestock. The eruption melted some of the ice-sheet covering Katla, flooding surrounding farmlands with a torrent of water that some accounts have said measured as wide as the Amazon.
Now, clusters of small earthquakes are being detected around Katla, which means an eruption could be imminent, seismologists say. The earthquakes have been growing in strength, too. After a long period of magnitude 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 are tracking the spike in seismic activity and working with disaster officials to prepare communities near Katla like Vik, a small town of some 300 people that is flanked by black sand beaches.
Civil defense authorities have been holding regular meetings with scientists. Disaster officials have also drafted an evacuation plan and set aside temporary housing, but many fear they may have less than an hour to evacuate once the volcano erupts.
Iceland sits on a large volcanic hot spot in the Atlantic’s mid-oceanic ridge. Eruptions, common throughout Iceland’s history, are often triggered by seismic activity when the Earth’s plates move and magma from deep underground pushes its way to the surface.
The longer pressure builds up, the more catastrophic an eruption can be. Records show that Katla usually has a large eruption twice a century. Since its last eruption was almost exactly 93 years ago, it is long overdue for another, seismologists say.
Icelanders are getting nervous as they mark the anniversary of Katla’s last blast.
“We’ve been getting calls recently from people concerned that Katla is about to erupt because it erupted … in 1918 on Oct. 12,” said Einar Kjartansson, a geophysicist at the Icelandic Meteorological Office.
“As scientists we don’t see that much of a correlation in the date but there is most definitely increased activity. The question is whether 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 jet stream, killing thousands of people with toxic fumes in the British Isles alone.
