by Alicia M Prater PhD

Created on: April 22, 2010   Last Updated: September 14, 2010

After the first tremors of an eruption in early March 2010, the Eyjafjallajokull volcano in Iceland wreaked havoc – spewing multiple ash clouds that closed airports across Europe, spurring the evacuation of 500 people, and just avoiding melting part of the Eyjafjallajokull glacier – but it’s not done. In April 2010, Iceland was bracing for an even bigger potential eruption, but not from Eyjafjallajokull, from a more powerful and threatening volcano – Katla.

Iceland is an island built on previous volcanic flow. The residents are used to their home stirring up trouble. When Laki blew in 1783 it released 120 million tons of sulfur dioxide into the air upon blowing its top, killing a quarter of the Icelandic population, causing famine and drought, spreading a toxic cloud over Europe, and altering the climate as far as Egypt and the United States, and it isn’t even considered in reports to be one of the island’s major volcanoes. Katla, though, is, and the remnants of a Katla eruption in 1755 are reported to still be found in the peat bogs of Europe. In contrast, Eyjafjallajokull is a relatively small volcano with rather small effects, but it has erupted three times in the past thousand years, each time setting off the powerful Katla.

How does one volcano trigger another? The two volcanoes in question are only 12 miles apart and share an eruption channel, with the magma flowing from one to the other as the pressure builds beneath the rock. Eyjafjallajokull erupted twice in early 2010, first on March 20 with the flow lasting 3 weeks, and then again on April 14. Its previous eruption, in December 1821, lasted for a year. Lava flowed ten times faster out of the fissure after the second eruption than after the first, possibly indicting more pressure. Data from the past decade also showed that magma was building along western side of Katla. In May 2010, scientists issued a warning that seismic activity indicated almost certain eruption at some point in the near future (MSNBC).

The news about Iceland's twin troublemakers has been rather quiet in North America since the end of Spring, but the residents of the nearby village of Vik are likely not as complacent. In April they were going over their evacuation plans, well aware of the devastation and flooding a Katla eruption can bring because of the effect on the Myrdalsjokull icecap under which it resides. Their strategy? Go to higher ground. According to Volcano Discovery, Katla regularly produces glacial flooding as one of Iceland’s most active volcanoes. The ice in the caldera rim, where most fissures occur during eruptions, is hundreds of meters thick. In 1999, the volcano caused flooding simply by heating up. Even before March's ash and fire show 12 miles away, experts were expecting Katla to erupt some time relatively soon based on its history and lack of a recent release.  

The few weeks of closed airports in Spring 2010 may just be the beginning. Floods, lost farms, months of altered weather – a lot of trouble could be afoot, and not just for Iceland. Its most powerful volcanoes have been known to spew toxic gases and ash that affect Europe, North Africa, and America as well.

Learn more about this author, Alicia M Prater PhD.
Click here to send this author comments or questions.