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Katla

Katla is an active subglacial volcano in southern Iceland, buried beneath the Mýrdalsjökull ice cap.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Katla is an active subglacial volcano in southern Iceland, buried beneath the Mýrdalsjökull ice cap. It is one of Iceland’s most active volcanic systems and is known for explosive eruptions that can trigger glacial outburst floods. Its last confirmed major eruption was in 1918.

Geography and setting

Katla lies beneath Mýrdalsjökull in southern Iceland, near the South Coast. It is part of a broader volcanic system in the Eastern Volcanic Zone and is covered by a thick ice cap.

Volcanic activity

Katla is among Iceland’s most active volcanoes, with many eruptions documented over the last millennium and longer. Sources describe its activity as dominated by explosive basaltic eruptions, with occasional larger fissure-style eruptions.

Hazards

Katla is closely watched because eruptions can produce tephra and jökulhlaups, or glacial outburst floods, when volcanic heat melts overlying ice. This combination makes it one of Iceland’s most hazardous volcanoes.

Monitoring and current status

Icelandic authorities and researchers continue to monitor Katla for seismicity, geothermal activity, and meltwater changes. As of 2026, available sources report no immediate sign of an eruption.

Key facts

  • Katla is hidden beneath the Mýrdalsjökull ice cap in southern Iceland.
  • It has a large caldera, commonly described as about 10 km across.
  • Historical records indicate many eruptions, with at least 20 documented since the early medieval period.
  • Eruptions are often explosive and can melt ice, causing glacial outburst floods.
  • The last confirmed eruption that broke through the ice occurred in 1918.
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Canadian context

Canadian readers may know Katla from Iceland travel, geology, and volcanic hazard coverage; its eruption risk can also interest Canadian aviation and climate researchers because Icelandic ash clouds can affect North Atlantic air routes.

Frequently asked questions

What is Katla?
Katla is a subglacial volcano in southern Iceland, located beneath the Mýrdalsjökull ice cap.
When was Katla’s last eruption?
The last confirmed eruption occurred in 1918.
Why is Katla considered dangerous?
Its eruptions can be explosive and may melt ice rapidly, producing jökulhlaups, or glacial outburst floods.
How active is Katla?
It is regarded as one of Iceland’s most active volcanic systems, with many historically documented eruptions.
Where is Katla located?
It is in southern Iceland, beneath Mýrdalsjökull, near the South Coast and the village of Vík í Mýrdal.
Is Katla erupting now?
Available 2026 monitoring information reports no immediate sign of an eruption.

References

  1. Encyclopaedia Britannica — https://www.britannica.com/place/Katla
    Supports: Katla as a subglacial volcano in southern Iceland; location beneath Mýrdalsjökull; caldera size; eruption history.
  2. Icelandic Meteorological Office — https://www.vedur.is/volcanoes/katla/
    Supports: Volcanic system location in Mýrdalsjökull and Eastern Volcanic Zone; size of volcanic system; caldera dimensions; active fissure swarm; historical activity; last eruption in 1918.
  3. Smithsonian Institution, Global Volcanism Program — https://volcano.si.edu/volcano.cfm?vn=372030
    Supports: Katla’s caldera dimensions, subglacial character, eruption styles, and historical explosivity.
  4. Wikipedia — https://en.wikipedia.org/wiki/Katla_(volcano)
    Supports: General overview; active subglacial volcano in southern Iceland; at least twenty documented major eruptions; last major eruption in 1918.