Tag Archives: Geology

The most volcanic part of Iceland: Krafla

2018 Trip to Iceland

 

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.

Land of Fire & Ice

2018 Trip to Iceland,

There are few places in the world more interesting than Iceland. Iceland, is one of the most volcanically active places on the planet because it straddles a divergent boundary between two tectonic plates that is called the Mid-Atlantic Ridge where the Eurasian and North American tectonic plates are being pulled apart. The Mid-Atlantic Ridge actually runs from the Arctic Ocean to the South Pole dividing the North American and European continental tectonic plates and cuts right across Iceland  from the southwest to the northeast. I believe that some day, as a result Iceland will be split apart. This ridge is marked by a belt of volcanic craters, hot springs, steam springs, solfatars (areas of high temperature activity) and earthquakes.  Frankly, in this region, it always felt as if a volcano or some immense power from deep in the earth would erupt at any moment or an earthquake would make its presence felt. This belt is about 40 km (25 miles) wide in the north and up to 60 km. (40 miles) across the south. About 25% of Iceland is covered by this belt. It is everywhere.

Evidence of subterranean unrest has been felt in many places, but in particular Mount Krafla near Lake Mývatn where we drove through on our exploration of Northern Iceland.  This area was free from volcanic activity for more than 200 yeas until 1724 when it experienced a massive eruption that lasted for about 5 years. That lava flow did not stop until it got to near to  Reykjavik right where a church congregation had gathered to pray for deliverance and got it. A miracle? Divine intervention?

Much of the island conceals seething mass of volcanic and geothermal activity.  When you think about it, that is a little scary. There are more than 100 volcanoes in Iceland. 35 of them have been active in the past 10,000 years, which of course in geological times is the blink of an eye. In the past century Iceland has experienced an eruption every 5 years.  Many of them are called “tourist eruptions” because they last for a short time and excite the tourists, like the eruption of Mount Hekklain 1991.

Others cause more trouble, like the eruption in 2010 of the volcano Eyjafjallajökull that erupted under a glacier.  The ash cloud that was produced reached a height of 10km. (6mi.) and brought airplanes to a halt across Europe for 6 days. That episode cost an estimated €4 billion. About 20 countries closed their airspace to commercial jet traffic and it affected approximately 10 million travellers. It was the largest disruption of air travel since the Second World War.

At the time Chris and I were on a trip to China and feared our travel plans might be disrupted but we were far enough away to miss most of the excitement, except that in Chongqing where we waited about 10 hours in the airport while all planes were delayed or cancelled. I wonder if the two incidents were related. At the time we were never told anything other than that the delay was weather related. From April 14-20, ash from the volcano covered large areas of northern Europe.

This is just one way that this tiny little island of Iceland ,with less people on it than in Winnipeg, has punched above its weight in terms of effect on the planet. As my Guidebook says, “It has been estimated that one-third of all lava that has erupted on earth in recorded history has come from Iceland.”[1]

One of the world’s most catastrophic eruptions occurred in the south of Iceland when Lakagígar exploded in 1783. According to my Guidebook, “it poured out the largest lava flow ever produced by a single volcano in recorded history, with a volume of about 12 cubic km (3 cubic miles).  But that was not all of it. After that it also poured out noxious gases that poisoned crops, livestock and blocked out the sun to such an extent a disastrous famine followed. At least 20% (10,000) of the people in Iceland died, and many more around the world.  Much of the loss of life was caused by the subsequent “Haze famine.” Actually it led to famines around the world for years, and helped to cause the French revolution and other uprisings around the world.

The big problem with volcanoes on Iceland is the fact that so much of Iceland is covered with ice (about 11%).  When fire meets ice all hell breaks lose!  According to my Guidebook, “Eruptions from subglacial volcanoes often cause more damage than those from open-air volcanoes. Hot lava melts the ice triggering sudden floods—jökulhlaups—with unpredictable results. Mount Katla, the volcano lying dormant under the glacier Mýrdalsjökull, is Iceland’s largest caldera, at 80 sq. km. (30 sq. mi.) When Katla erupts the scientists have calculated that the jökulhlaups can be 200,000 cubic metres (7 million cubic ft.).

When a volcano in the Bárδarbunga-Grísvötn fissure erupted  in 1996 beneath Vatnajökull the largest glacier in Europe it pushed such massive amounts of ice and over a 100 sq. km. (60 sq. mi.) area. When the ice started to melt because of the power of the volcano the melt-water flowed into a caldera beneath the glacier. When that caldera filled up the water spilled over the brim creating massive flooding across the sand plain south of the glacier (where we later travelled) washing away any roads and bridges in it path. It dropped icebergs as big as apartment blocks that turned the sand into quick sand when they melted. Life is never simple when fire and ice mix.

In 2015, the Bárδarbunga-Grísvötn volcano became active again throwing 12 million tons of sulphur dioxide into the atmosphere and creating a lava field as big as Manhattan.

Volcanic eruptions occur about every 5 years in Iceland. There were more than 20 in the 20thcentury. Most of them go unseen beneath Vatnajökull the largest ice cap in Europe. 2 famous ones did not go unnoticed. The first was in 1963 and occurred off the south coast. When it erupted it created an entirely new island called Surtsey and we could see it faintly on our trip in the south part of Iceland. The second, a decade later, surprised everyone because it blew up in a volcano that was believed to be extinct. It was located on an island called Heimacy but the people were lucky because the fishing fleet was moored in the harbour that night and everyone of the 5,200 inhabitants was successfully evacuated. It extended the coast by about 5 km. The effects of fire and ice are profound.

 

 

 

 

[1]Insight Guides:Iceland(2017) p. 21