Two years ago, the eruption of the volcano Eyjafjallajökull caused havoc across Europe, with airborne ash grounding flights for six days. 

The Eyjafjallajökull ash cloud. Photo by Páll Stefánsson.

Eyjafjallajökull may be quiet now, but, according to The Telegraph, activity has been increasing in the volcano belt that stretches diagonally across the middle of Iceland from the Westman Islands in the south to the Lake Mývatn area in the north, along the line of the American and Eurasian geological tectonic plates.

This region includes the volcano Katla, which has erupted about every 60 years (the last time in 1918), the volcano Hekla, which has erupted approximately once every ten years in the past decade (the last time in 2000), and Grímsvötn, which had a short eruption last year. 

In the 17th and 19th centuries, eruptions of Eyjafjallajökull were followed within months by eruptions of Katla, and now too, Katla has been increasingly restless. 

Increased activity has also been detected in the volcanoes under the largest ice cap, Vatnajökull, which is where Grímsvötn lies. 

In July 2011, geothermal heat caused melting in Mýrdalsjökull, the ice cap covering Katla, producing a flood that destroyed an important bridge on the south coast of Iceland at the height of the tourist travel season. 

According to precise GPS measurements, there has been movement of the surface of the volcano, as well as bursts of high earthquake activity beneath Katla’s caldera, indicating that magma has risen closer to the surface. 

Scientists have been monitoring the volcano closely ever since the glacial burst last July and every now and then earthquakes have caused concern that an eruption might be coming up. Yet while repeatedly making headlines last autumn, Katla has been rather quiet in recent months.