Unexplored Iceland: Raufarholshellir Lava Tube


As a volcano was erupting just outside of Reykjavik, what better way to appreciate the power of techtonics than visiting a lava tunnel?

Raufarholshellir Lava Tube is the fourth largest in Iceland- its 30m high and 10m wide chamber stretching for nearly 1.5kms. It was formed by flowing lava around 5200 years ago, during the Leitahraun eruption. The relatively slow flow of low-viscosity lava formed a hard upper crust, which thickened to form the roof whilst lava was still flowing beneath it. As the lava flowed out, the hollow of the tube was left behind.

The shelter of the lava tube was a welcome escape as a blizzard whipped up outside, snow settling inside the first few metres of the tunnel. Further inside the tunnel, snow had also accumulated beneath the many “skylights”, which are holes in the ceiling. Locals have been known to jump through these skylights, when the snow is thick enough to provide a soft landing.

The geological features within the tunnel were fascinating- horizontal lines showed different levels of lava flow, and minerals in the molten rock produce a stunning range of colours within the tunnel. The cave also contains microbial mats, which are sheets of bacteria on the rock, like a living wall of tiny lifeforms.

Lying just outside of Reykjavik, this lava tunnel offers a unique glimpse into the volcanic underground of Iceland. It is accessible only by guided tours- which can be booked as an excursion from the city, or on location if you’re traveling around the country by car.

Last Updated on 27 March 2024 by Michael


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