Inside The Volcano

The expanse of Iceland is marked by geological change, and a traveler does not have to go far to explore the natural wonders caused by glacial melting, volcanism, and tectonic activity.

One of these wonders is Thrihnukagigur, a crater formed during a volcanic eruption that occurred 4,500 years ago. The crater is a magma chamber. During the volcanic process, it held all of the molten rock until the pressure inside eventually caused a fracture in the side of the volcano. This is what results in an eruption. Typically, magma chambers close after an eruption from the cooling of the lava. Thrihnukagigur is unusual in that the lava seems to have solidified into the walls of the chamber or drained out into the earth, leaving a spacious cavern behind.

The adventure starts about 3 kilometers away from the volcano. My colleague, Emily Matelan, and I were dropped off at the meeting point, a two-story building in the Blafjoll (Blue Mountains) parking lot, where we met with the rest of our group. The weather that day marked the end of Icelandic winter weather. The temperatures in nearby Reykjavik were in the 40s when we left, but when we arrived at the volcano, there were severely high winds. We had been dressed for Reykjavik weather, but fortunately we were provided with  bright yellow raincoats that served as windbreakers. These simple and thin coats on top of our polar fleece and flannel were enough to keep us comfortable considering the long, windy hike ahead of us!

We set off in the rocky, moss-covered lava field with Gisli, our guide, leading the way. He stopped every now and then to point out crevices in the ground that were the result of volcanic activity. After 45 minutes of hiking, we reached the base of Thrihnukagigur. Gisli took us to a small cottage that served as base camp for the hike up the volcano, and we took the opportunity to get shelter from the wind and cold. When we arrived, they gave us stew and coffee to warm up. Gisli split us into two groups so we could descend into the volcano safely and separately. Our group went first. We removed our raincoats and were fitted in helmets and harnesses before going back outside to make the final ascent up the side of the volcano.

The lift going into the volcano could fit about 6-8 people. The sides of the lift had been fitted with rubber and wheels to gently bounce off of the narrow sides of the cave entrance without shaking the lift or hurting the rock. The lift then descended slowly down into the magma chamber. As the descent went on, the chamber opened up into a breathtaking expanse. The ground was lined with jagged rocks, and the colors on the wall of the chamber appeared in varying shapes and shades. After we had descended about 700 feet, the lift reached the floor of the chamber and we all stepped off.

There was a path that went all around the circumference of the chamber, lined by some rigging to help you step over parts of the chamber that were completely overrun with rocks. We spent a half hour clambering over rocks, viewing the coloration on the walls, and simply marveling over the fact that we were in the heart of a volcano. It was humbling to be in a place that had been the site of a force of nature.

I will make this disclaimer: The “Inside The Volcano” tour is definitely not for those who are severely claustrophobic or afraid of heights. The descent into the volcano via the lift is slow and lasts about four minutes, and affords much time to see how far down one goes. Those with a mild fear of heights would do well to just look ahead rather than down. The chamber itself is rather spacious; the ground space is 160 x 220 feet. There is no part of the path within the cavern that is narrowly-confined. The chamber itself is a large enclosed space, and the small opening at the top is a reminder that one is deep inside the heart of a volcano.

That thought is a wonder in itself, but I can also see why it would be intimidating to anyone who is already claustrophobic. My suggestion is to know what to expect, and to know your limits.

When we were done exploring the depths of Thrihnukagigur, we went back up the lift and back into the daylight. The lava field below stretched out before us, giving quite a different sensation after the experience in the recesses of the quiet and dim magma chamber. As we trekked back to our starting point, I felt elated. It is difficult to put into words, but the sense that I was able to visit a piece of the earth that under different circumstances would have been closed off to myself and others is something I will always remember when I look back on my time there.

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  • Lois and I did this in July this year prior to fishing at Laxa. Agree with your advisories. Very interesting to learn the geology of a volcano. Great photo opportunities inside with the different minerals. Nice half day trip from Reykjavik. Jonathan Sastic P.S. Best lamb stew I’ve ever had!