Katla is one of the largest volcanoes in Iceland, situated to the north of the village Vík in Mýrdal valley and to the east of the smaller glacier Eyjafjallajökull.
The Katla volcano is located in southwestern Iceland, not far from the infamous Eyjafjallajokull volcano, which belched out tons of ash in 2010.
The ash from that volcanic eruption caused tens of thousands of trans-Atlantic airline flights to be canceled, wreaking travel havoc worldwide.
Its peak reaches 1,512 meters (4,961 ft) and partially covered by the Mýrdalsjökull glacier. The system has an area of 595 km2 (230 sq mi). The Eldgjá canyon is part of the same volcanic system.
Evgenia Ilyinskaya, a volcanologist at the University of Leeds, and her colleagues have discovered that Katla is pumping out vast quantities of carbon dioxide. Gas measurements taken above the ice-capped volcano (using aircraft), combined with modelling, reveal that Katla is one of the biggest volcanic sources of carbon dioxide (CO2), releasing about 20,000 tonnes every day – approximately 1% of the UK’s daily CO2 emissions.
Their findings, published in Geophysical Research Letters, indicate that this explosive volcano likely has magma sitting deep down in its roots. By continuing to monitor the CO2, the scientists hope to be able to decipher when more magma arrives, and forewarn if it starts building up to an eruption.
“Scientists have seen this previously happen at Kilauea volcano in Hawaii, where carbon dioxide emissions increased a few years before an eruption happened. Now we need to see if Katla will give us a similar calling card,” Ilyinskaya said.
The eruption of Katla (1918)
The last time Katla seriously erupted was in 1918. Sand deposits from the flood extended over the south coast by up to 5 kilometers.
Fortunately there were no casualties, but a group of farmers who at the time were rounding up sheep had a narrow escape.
The men were close to Álftaver when they heard the heavy booming sounds. They saw there was nothing for it but to immediately head in the direction of Skálmabæjarhraun lava field, the highest point in the surrounding landscape.
A short time later they could see the massive glacial tidal wave bearing down. Forced to abandon their unfortunate livestock they galloped away from the approaching flood.
The history of Katla
Katla is one of Iceland’s most active volcanoes. Katla has erupted every half-century or so over the last millennia with the last large eruption in 1918. Katla is thought to have had three small eruptions since 1918, but these volcanic bursts never breached the dense ice cap.
Katla’s ice cap reaches 2,300 ft (700 m) at some points.
Volcanoes under an ice cap are a common feature of Iceland. Their eruptions melt the enclosing ice, forcing the meltwater, rocks, sand, and silt to burst out from under the ice cap in a violent stream.
This natural phenomenon is called a jökulhlaup or a glacier outburst flood. The most recent Katla’s jökulhlaup occurred in 2011. It was so powerful, it washed away the bridge over the Múlakvísl River.
The ice cave
Katla volcano is a mysterious gem. There is a secret ice cave you can visit hidden beneath its thick layer of ice. Enter Mýrdalsjökull’s outlet glacier Kötlujökull through an ice gate that looks like it’s the doorway to a magical ice kingdom.
The natural ice cave is located above the notorious volcano and it takes you as close to Katla as you can get.
From the moment that you step into the cave, you enter a completely different world that resembles nothing you’ve seen above ground. Mesmerizing blue colors alternate with black layers and the ice glitters as the sun rays play on the walls.
The inside of the cave can best be described as having the appearance of turquoise, black, and white wavy textured glass. It is formed by melting glacier water carving openings or pockets in the ice.
When will Katla erupt?
Seismic activity in Katla has, in recent years, been mainly characterized by shallow seismicity in the caldera. The seismicity intensifies in late summer and during the fall, an effect which is probably unrelated to volcanic processes.
Compared to other volcanic systems in Iceland, Katla volcano is one of the most seismically active. Deformation studies in recent years do not indicate significant deformation caused by magma influx and accumulation. Despite that, several studies indicate magma storage in the roots of the volcano. This is suggested by an extensive geothermal area within the caldera.
At this stage, it is difficult to forecast the next eruption of Katla. However, before the next eruption, it is expected that IMO’s monitoring systems will detect precursory activity, such as increased seismicity, changes in seismic patterns, inflation of the volcano, changes in gas-fluxes and ratios, and changes in hydrological measurements.