Mount Katla

CODEX Entry 3441: Mt Katla


Katla, or Kettle, 40 km south east of Hekla, is very active, with twenty eruptions between 930 and 1918. The volcano normally erupts every 40–80 years, but has now not erupted violently for 103 years, although there may have been small eruptions that did not break the ice cover in 1955, 1999, and 2011.


The caldera of the Katla volcano has a diameter of 10 km and is covered with ice 200 to 700 metres thick. The flood discharge at the peak of an eruption in 1755 was comparable to the Amazon, Mississippi, Nile, and Yangtze rivers combined. It is thought two very large eruptions of Mt. Katla 12,000 and 11,500 years ago may have helped move the Northern hemisphere out of the previous Younger Dryas ice age. It is the source of 7 cubic kilometres of Vedde Ash, volcano dust scattered from Greenland to Scotland.


The last major eruption started on 12 October 1918 and lasted for 24 days, coinciding with the German Revolution and their collapse on the Western front. The severe fissure eruption in 934 was one of the largest lava eruptions in the past 10,000 years. Katla’s present dormancy is among the longest in known history. Katla has been showing signs of unrest since 1999, and geologists have concerns that it might erupt in the near future. Monitoring intensifies when smaller neighbouring volcanoes are active. In the past 1,000 years, all three known eruptions of neighbouring volcanoes have triggered subsequent Katla eruptions.


In 2010 the Eyjafjallajökull eruptions next to Kapla, disrupting flights across Europe raised concerns that Kapla may soon be awoken. A video taken of this eruption appeared to show a UFO exiting the crater.


Katla is the largest volcanic source of carbon dioxide on Earth, accounting for up to 4% of total global volcanic carbon dioxide emissions of 360 million tonnes per year. This includes oceanic volcanoes. However humanity’s annual carbon emissions through the burning of fossil fuels and forests are 100 times greater than all volcanic emissions combined. Just 0.2% of Earth’s total carbon, about 43,500 giga tonnes, is above the surface in the oceans, on land, and in the atmosphere. The rest is subsurface, in the crust, mantle and core, an estimated 1.85 billion gigatonnes. Immense, catastrophic releases of magma have occurred five times in the past 500 million years. During these events, huge volumes of carbon were outgassed, leading to a warmer atmosphere, acidified oceans. and mass extinctions. Similarly, the Chicxulub bolide meteor strike on Mexico’s Yucatan peninsula, released as much CO2 as humans will in the next 30 years, approximately 1000 Gt of CO2, which rapidly warmed the planet, killing 80% of plants and animal species, including the dinosaurs. Monitoring changes in CO2 emissions in volcanoes is an effective way to predict coming eruptions.