Thursday, August 18: After leaving Dimmuborgir in Eastern Mývatn, we drive to our next destination in the Krafla volcanic region, which encompasses an 818m-high, 10km wide caldera and a geothermal power station. We plan to walk through Leirhnjúkur, a black lava field and its solfataras, within Krafla. Solfataras are volcanic areas or vents that yield only hot vapors and sulfurous gases.
On our way, we pass the Krafla Power Station. Built by the Icelandic government, construction began with trial boreholes in 1974; the first turbine unit started up in August 1977, and regular operations began in February 1978. Krafla came under the ownership of Landsvirkjun, the National Power Company, in 1985 (Landsvirkjun).
The name Krafla also refers to the fires that erupted on and off in the period 1975-84. The events were a striking repetition of what happened during the Mývatn fires which occurred between 1724–1729, when many of the fissure vents opened up. Fissure vents are linear ruptures through which lava erupts, usually without any explosive eruptions.
A collapsed, but still active, volcanic area, Krafla has recorded 29 eruptions, the most recent of which were the Krafla Fires. In the 1975-1984 period, nine volcanic eruptions and fifteen uplift and subsidence (downward motion of the earth’s surface relative to sea level) events were recorded (Wikipedia: Krafla).
It’s a 20 minute walk through moss-covered lava that originated from the 18th century Mývatn fires. The landscape is fascinating with its carpeted boulders of lava.
To our east, we can see the crater Viti. This 300m-wide explosion crater was formed in 1724 at the beginning of the Mývatn fires. We originally plan to walk around the rim of this crater, but our walk around Leirhnjúkur is so long and time-consuming that we don’t have time to do it.
To our west we can see Leirhnjúkur, a rhyolite formation 593 meters above sea level. The hill rises less than 50 meters above the surrounding lava field. The rhyolite of the hill is porous due to the geothermal heat and has in several places turned into clay, hence the name Leirhnjúkur — “clay hill.”
After our long walk across the lava field, we are finally in the midst of the craters, steaming vents and fissures of Leirhnjúkur.
There are warnings about the danger of this area, as it’s still active and there are many hot spots. We stay on the relatively safe marked trails, including many wooden walkways, around the field, crossing older lava covered in vegetation before climbing onto the darker, rougher new material. Stains of red or purple mark iron and potash deposits, while white or yellow patches indicate live steam vents to be avoided (Rough Guides: Leirhnjúkur).
Several mud-pits and steam vents are located on the northern slopes of Leirhnjúkur.
The magma boasts a full spectrum of colors, with the greens of moss and lichen next to the scorched earth colors of sulphur and rhyolite (Visit Húsavík: Krafla Caldera).
When we get to a high viewpoint, we can see Gjástykki, where the main area of activity was during the 1980s. It’s a black swathe between light green hills, amazing in its scope.
This is our third walk of the day, and it’s a long one! By the time we finish, it’s after 3:00 and we still have to visit the mighty waterfall of Dettifoss, at the southern end of Jökulsárgljúfur and then drive a long haul to the eastern town of Seyðisfjörður. Already my legs are aching.🙂