After touring the island with our Smithsonian guests for nine days, I had a free day while in the capital city of Reykjavik. A chance opportunity to go on a local tour known as "Inside the Volcano" popped up for me. I jumped on it! This is an excursion a short drive out of Reykjavik where visitors descend about 150 meters through a narrow vent into an extinct cinder cone. Of course, I said yes to the opportunity.
After the 45-minute drive out of the city and toward an upland area, visitors are brought to a waiting room where they receive instructions and rain gear.
I was impressed with the signage inside the waiting room, which graphically explained the age, composition, and eruptive history of the volcano. A great resource for folks to understand the deeper story of the "thrill descent."
The cone is called Ᵽrínúkagígur (Ᵽrínúka Crater) and it was formed about 4,500 years ago in a post-glacial eruption. Iceland classifies its younger volcanoes as glacial or post-glacial. Ᵽrínúkagígur is one of three closely-spaced scoria cones (also called cinder or tephra cones) erupted along part of Iceland's southwest rift, part of the Brennisteinsfjöll (Sulphur Mountain) rift.
A loop trail over very coarse rubble can be made. This is not for the faint of heart - the lighting is low, the trail very rough and water constantly drips down from the roof making things slippery.
The temperature is quite cold at about 38º F and many people found gloves useful on the trip. After 4500 years, the inside of the volcano has cooled sufficiently.
The colors are due to the various states of oxidation adjacent to the dikes in the walls.
This was a very unique trip. It is somewhat expensive being about $300 US per person. But it does include excellent and geologically literate guides, a bowl of hot, Icelandic meat soup in their kitchen near the volcano, hot tea and coffee, and heaps of fresh Icelandic air (and likely rain). See their website for more information here.
