The Krafla area is an area with “fissure swarms.” That meant there were a number of punctures of the earth’s surface through which volcanically heated water escaped in steam, mud bubbles, and odours. The area was only about 5 km from Lake Mývatn. Here we saw am amazing contrast in landscape from the green countryside we had passed until then. The vegetation changed from saturated green to barren yet a colourful variety of geothermal orange and ochre.
The Krafla area and the geothermal areas are all part of the same central volcano caldera that measures approximated 40 km2. It is divided into 2 main areas. The upper area reaches 1,000 metres in depth and reaches a temperature of 200ºC. The lower part reaches a temperature of 300ºC. The closer to the centre of the earth the hotter it gets. The surrounding boiling mud pools and steam vents are clear evidence of volcanic activity below the surface. The surface activity is bound closely to areas above the magma chamber of the volcano.
There is little surface water in the region because it slips into porous lava. Hot spring areas like this are rare in the world but they create a unique ecosystem for microorganisms. Most are not visible to the naked eye. One of these is a green algae called Cyanidum caldarium. Another is the ancient (and I mean really ancient) bacteria called Archaea which is the most common in hot springs and is among the 5 oldest organisms in the history of the earth! Think about that. Could this be the original common ancestor of us all? Some of the organisms here are among the most temperature resistant on earth and can survive in temperatures of 60ºC. The results of these organisms are the colored displays.
Mount Krafla is not your classic cone-shaped volcano. It has been worn down and exploded beyond recognition. If you would not see the bubbling water, escaping gases you would not know you were in the presence of a volcano. This mountain was the source of a volcanic explosion in 1724 that blighted crop production for many years afterwards.
Underneath the Krafla field lies a magma reservoir between 3 and 8 km (2-5 miles). That reservoir is the source of all the volcanic activity which we witnessed or inferred in the region. Magma builds up in that reservoir and that pushes up the earth above that reservoir until it is released as rock intrusions or volcanic eruptions. After that, of course, the earth sinks again until it again starts to rise.
The area is created because cold water drips down through the porous soil to the magma intrusions where that water is super-heated and transformed into steam which is ejected out again to the surface. The sulphur hydroxide is responsible for the hot spring smell we have come to know and love. Sulphur deposits are formed when fumarole gases mix with the air and a mixture of gypsum and silica also forms around the fumaroles. In the mud pots, fumarole gases rise through surface water creating sulphuric acid which makes the water very acidic. Rock and soil mix in the hot water and acid producing the mud of the mud pots.
In the early 1970s, “Krafla fires” began with a dramatic spurt of molten lava that lit up the sky. Over the next 10 years there were 17 eruptions. People in the nearby village of Reykjahlíδ were lucky because the lava flowed away from it. Ominously volcanologists are expecting Krafla to blow again. We hoped it would not blow soon.
Interestingly, in 1984 when the authorities put up a stern warning sign in the parking lot for tourists to stay away, it had the opposite effect and attracted tourists. Tourists are not famous for being smart. Some of them are downright oppositionally defiant. This is particularly true of those who want to grab a photograph. I know some photographers like like that. They are stupid. And life is hard when you are stupid. So what did the authorities doe? They removed the warning signs. Icelanders, unlike North Americans, are like that. They don’t worry so much about law suits. My guide book had some good advice about this region, “If you can forget the disconcerting possibility of being blown to kingdom come, this whole lifeless, primeval area gives as good a glimpse of the freshly formed earth as anyone is likely to get.”
There was a geothermal power station with long lines of above ground pipes in the region. According to my guidebook, “Pipes from the Krafla geothermal power plant form a metal doorway to the area, which is strangely appropriate; the construction of the plant in 1973, with its many bore holes into the earth’s crust, is considered by some scientists to be responsible for triggering the eruptions that began here in 1975—the first since the 1700s.
The first place we stopped was Víti, which means“mouth of hell.” That is enough to give anyone pause. There are two craters in the area called Viti. The one we saw was formed by the steam explosion in 1724 during the Mývatn Fires. The one we saw was inside a dingy brown explosion crater with a pool of cold blue water which we should not confuse with the other Viti crater that is farther south. Its turquoise water were warm and full of bathers. The one we saw was empty of humans. No one was anxious to go to hell.
Mt. Námafjall (485 metres above sea level) is coloured orange and yellow. It is one of Iceland’s largest sulphur spring areas. This was obvious from the smell. AO told us that if we had to release some gas this would the appropriate time.
One of the many geothermal areas of Iceland in the Iceland area that we passed in the Krafla region was called Hveraröndor Hverir. It covers some 4 km2. This area is extremely barren with big fumaroles, which are openings in the crust of the earth usually found in volcanic areas like were travelling through. We have seen them before in Yellowstone National Park in the US and in New Zealand. Fumaroles emit steam and gases such as carbon dioxide, sulphur dioxide, hydrogen chloride and hydrogen sulphide. The steam is formed when superheated water condenses as its pressure drops when it emerges from the ground.
A fumarole can occur wherever there are tiny fissures, often in chaotic clusters or fields, and on the surface of lava flows or thick deposits of pyroclastic flows. A fumarole field is an area of thermal springs and gas vents where magma or igneous rocks at shallow depths release gases or interact with groundwater.
We stopped in this region for a walk to get a closer look at the boiling mud holes, fumaroles, and even a pile of steaming rocks. The entire area is often called “eldhús djöfulsins” in Icelandic, or Hell’s (Devil’s) Kitchen because of these steaming pots and hissing sounds and the strong smell of sulphur.Sometimes the fumes can be overwhelming.