The Colourful Caldera of Kerið


Source: B. Weber, Licensed under the Creative Commons Attribution 3.0 Unported licence. Click the image to view the image at its full size of 4925 x 7848.

That eerily gorgeous locale in the photo above is the lake known as Kerið (roughly ‘pot’, ‘basin’ or ‘bowl’) in southwest Iceland, located about an hour east of Reykjavik by car. One of the more visually stunning legacies of Iceland’s volcanic origin, the Kerið caldera dates back 3 000 years and is one of several crater lakes in the area. What sets Kerið apart is both the structural form and the visually stunning nature of the caldera.Being half the age of neighbouring calderas, Kerið’s form has yet to deteriorate to the degree of its neighbours.


Kerið in July. Source: J. Agrippa, Licensed under the Creative Commons Attribution-Share Alike 2.5 Generic licence.

Kerið is believed to have been a cone volcano whose walls collapsed into the empty magma chamber left behind when the volcano’s magma reserves depleted. The crater measures 270 metres long, 170 metres wide, and 55 metres deep (890 x 560 x 180 feet). The red colour of the land surrounding the caldera comes from the oxidation of the iron in the volcanic rock (largely hematite). Adding to the colours of Kerið are the mosses and lichens that cover most of the caldera walls, as well as any tufts of grass that are able to embed themselves in the steep walls.


Source: Reykholt, Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported licence.

Kerið lake itself is rather shallow, fluctuating between 7 and 14 metres (23-45 feet) deep. It has no inflow from above, and is not simply a result of rainwater that has collected in the caldera, although rainfall does contribute to the fluctuation. Rather, the lake is mostly groundwater, the result of the crater bottom dipping below the water table. The water in Kerið is thus connected to another caldera in the area that dips below the water table; when water accumulates in one lake, it often takes away from the other and vice versa. The water of the lake is a vivid aquamarine thanks to the colloidal silica in the water which scatters blue light.


The lake at its bluest.Source: B. Suda, Licensed under the Creative Commons Attribution- 2.0 Generic licence.

Today, Kerið is included in the tourist route known as the Golden Circle, which takes in the attractions in the region east of Reykjavik, including the geysers Geysir and Strokkur; Europe’s largest waterfall, Gullfoss ; and Þingvellir National Park (the home of Iceland’s Althing (Alþingi), the world’s oldest parliament, from 930 to 1789, and of the largest natural lake in the country, Þingvallavatn). In 2000, musicians including Björk performed in the middle of the lake on a floating wooden platform, with the audience sitting around the slopes of the crater. The amphitheatre-like setting evidently made for great acoustics. Volcanoes and Björk. Does it get any more Icelandic?

Do yourself a favour and run a Google Image or Flickr search on Kerið. A lot of beauty packed into such a little place.

Further Reading

Nordic Adventure Travel (2011). Kerið. Available at Accessed 27 July 2011.

Steinþórsson, S. (2006). Hvernig myndaðist Kerið í Grímsnesi og hvers vegna er vatn í því? Vísindavefurinn, 2 March 2006. Available at Accessed 27 July 2011.

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