Þríhnúkagígur — volcano
Uaiecs · CC BY 3.0

Þríhnúkagígur

  • 1 min read
  • 63.998° N 21.699° W

Interesting facts

  • The chamber is deep enough that the Statue of Liberty could stand inside it with room to spare.
  • Its walls are streaked with red, yellow and orange mineral colours against black basalt, giving the cavity the look of a stained-glass cathedral.
  • In 2016 Chino Moreno of the band Deftones gave what was billed as the first public concert inside a volcano's magma chamber, for an audience of about 20.
  • The cavity survived because the magma drained back down into the earth instead of cooling and sealing the chamber, a rare outcome for a volcano.
  • The descent from the rim to the floor of the chamber takes about three minutes in the suspended cable lift.
  • Deep inside the volcano the air stays cold, around 5 to 6 °C all year round.

Why it is worth it

Þríhnúkagígur, the Three Peaks Crater, is a dormant volcano on the Reykjanes peninsula whose interior lies open: below a small opening in the summit a vast bottle-shaped cavity drops about 120 m into the earth. It is a rare place where it is possible to descend into the emptied plumbing of a volcano, standing at the bottom of a chamber that once held molten rock.

The crater belongs to the Brennisteinsfjöll volcanic system and forms the north-eastern member of a small group of craters, the Þríhnúkar. It has not erupted for about 4,000 years. At the surface the vent is only around 4 by 4 m, but beneath it the cavity widens into a space of roughly 150,000 cubic metres, with a floor around 48 by 60 m, comparable in size to a football pitch. Below the floor, volcanic conduits continue down to a depth of about 200 m. Strictly speaking it is not a magma chamber in the deep geological sense but the cavity of the eruption channel beneath the crater, from which the magma drained away rather than solidifying in place.

The cave explorer Árni B. Stefánsson first descended into the crater in 1974, and it was explored and mapped in detail in 1991. A cable-suspended work platform, similar to a gondola, was installed for a scientific expedition in 2010, and since 2012 small groups of visitors have been lowered down the throat of the volcano in it. The crater group has been a protected natural monument since 1973. In 2015 the Icelandic band Kaleo recorded a live performance in the cavity.

Getting there

Þríhnúkagígur lies about 4 km west of the Bláfjöll ski area, some 18 km from central Reykjavík. The nearest airport is Reykjavík Domestic Airport (RKV), about 19 km away; Keflavík International Airport (KEF) is about 44 km away in a straight line.

Plan your visit

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Nearby places

On these lists

The Most Beautiful Places in Iceland 41The Most Beautiful Volcanoes in Iceland 7The Most Beautiful Natural Wonders in Iceland 22The Most Beautiful Volcanoes 61The Most Beautiful Natural Wonders 580

From the encyclopaedia

Þríhnúkagígur is a dormant volcano in the volcanic system of Brennisteinsfjöll near Reykjavík, Iceland. Covering a 3,270 square metres (35,200 sq ft) area and a depth of 213 meters (699 ft), it has not erupted in the past 4000 years. It was discovered in 1974 by cave explorer Árni B. Stefánsson, and opened for tourism in 2012. It is the only volcano in the world where visitors can take an elevator and safely descend into the magma chamber. The magma that filled the chamber has drained away, revealing the void beneath the surface.

Wikipedia · CC BY-SA 4.0

63.99833, -21.69889per Wikidata