Geology
Eruptions
Volcanos
Hot springs
Glaciers
Geology
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Iceland is located on the Mid-Atlantic Ridge, which makes it one of the most tectonically active places in the world. There are over 20 high temperature steam fields that are at least 150 °C, many of them reaching temperatures of 250 °C.
Geologically speaking, Iceland is hardly out of playschool, since it only began to rise from the North Atlantic seabed about 25 million years ago, the product of volcanic eruptions that are still going on today. Parts of the country are still so rugged that American astronauts chose Iceland as a training ground to prepare them for landing on the moon.
Contrasting forces of ice and fire exist side by side in Iceland. Some 11% of Iceland is covered with glaciers and about 30% is lava fields. On average, a volcano erupts every five years, but fortunately only rarely where anyone lives.
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Eruptions
Skaftáreldar
“This said week, and the two prior to it, more poison fell from the sky than words can describe: ash, vocanic hairs, rain full of sulfur and salt peter, all of it mixed with sand. The snouts, nostrils, and feet of livestock grazing or walking on the grass turned bright yellow and raw. All water went tepid and light blue in colour and gravel slides turned gray. All the earth´s plants burned, withered and turned gray, one after another, as the fire increased and neared the settlements.”
– Rev.Jón Steingrímsson, Skaftáreldar 1783-1784.
Powerful volcanic eruptions, ashes and debris falling from the sky all over the country, acid rain, non-stop earthquakes, lava rocks being thrown into the air, travelling more than 100km, all-consuming fiery lava flows drowning villages, thunder and lightning adding to the effect, with the lightning sometimes providing the only visibility. Everything was either black with darkness or on fire.
The eruption lasted for 7 months. But the horrific weather and 600km2 of lava, still remained. The effects on the world were also quite noticeable as it not only affected the weather, but ashes fell all over mainland Europe and even as far as China the air became foggier as a result and dry fog was reported in N-America.
The ash, acid rain and toxins left behind all contributed to the nightmare that followed.
The next couple of years crops were ruined, the livestock died and so did the people, both due to the toxins and the famine that came with it. 25% of the nation perished in just 2 years.
Two volcanic eruptions in the Vestmannaeyjar islands area are the most noteworthy. These are the Surtsey eruption in 1963 and the Heimaey eruption in 1973.
The Surtsey eruption is the name of underwater volcanic activity, that took place on the seabed not far from Heimaey and lasted 4 years, 1963-1967. This activity created the island Surtsey, or the island of “Surtur”, which was one of the names for the devil. 2 smaller islands were also created, but have since then gone underwater. Surtsey Island is a National Reserve, used for scientific research and is invaluable in monitoring what happens to an island from it’s birth.
Heimaey eruption, refers to the island Heimaey, or Home-Island, which is the main island of the Vestmannaeyjar Islands, the one that is inhabited and the one that contains the volcano Eldfell, or Fire-Mountain, where the main eruption took place in 1973.
Without a warning the eruption started on the outskirts of town. On that first night, all five thousand inhabitants were evacuated and no lives were ever lost. After 6 months of activity on Heimaey, 250 million m3 of lava, ashes and debris had appeared, expanding the island by 20%. The debris buried about one-fifth of the town.
The story is a dramatic one and the aftermath is still visible for all to see. You can tour the crater area and feel the burning hot ash lying only centimeters below the surface. Steam rises from the ground, creating clouds that often obscure the view. Black basalt ash still lies everywhere. On the edge of the destruction, homes are half buried, straining under the weight of lava and ash. A lot was done both during and after the eruptions, including clearing ashes and lava off the houses every day, to prevent them being buried.
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There were also attempts to stop the lavaflow when it had already calmed down but was still moving toward closing the town harbor, a critical disaster for a fishing community. Extraordinary amounts of sea water were pumped and dumped on the edge of the lava flow which eventually cooled down and the lava stopped flowing, and actually improved the quality of the harbor.
Eyjafjallajökull eruption 2010
Holuhraun eruption 2014 – 2015
Volcanos
Grímsvötn is the most active volcano of Iceland. The Grímsvötn volcanic system has erupted 9 times in the last century and at least 71 eruptions have occurred in historical times. Grímsvötn lies under Vatnajökull glacier, and the fact that it is one of Iceland’s many ice-capped volcanoes makes it almost impossible to have an exact number of eruptions, as many occur beneath the ice without ever being noticed.
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Grímsvötn last erupted in 1998, but in 1996 a new volcanic ridge, Gjálp, was formed under the glacier.
When the volcanoes erupt, a very very large amount of ice, right above them, melts and flows southwards towards the sea. A stretch of coastline which normally contains about a thousand small meltwater rivers is completely inundated and becomes one massive river bigger than the Amazon, washing away anything in its path. The river flows for about 20 km until it reaches the sea. Because this happens regularly, there are no buildings or anything else in this area. There is a road, which is regularly washed away and rebuilt afterwards.
Katla
Katla lies under the glacier Mýrdalsjökull and is one of the most dangerous volcanoes in Iceland. Katla is believed to be the center of an 80km long, U-shaped volcanic area. This area includes, amongst other places, the Westmen Islands. When Katla erupts, its smoke forms a 20km high ash plume in the air, which can easily be seen from Reykjavik. That is, however, by no means the most dangerous thing about Katla’s eruptions. It is the melting glacier that goes with the eruption, which poses the greatest threat and the most destructive power.
The amazingly powerful water flow has been known to carry with it icebergs from the glacier, as high as 18m and as long as 200m. Despite this extreme force of the Katla eruptions, they usually do not last very long and due to the seismic activity that precedes them, we usually have close to a 6 hour warning. In the time since the settlement of Iceland, close to 1150 years now, Katla has erupted 20 times.
The time between eruptions has usually ranged from 60-80 years, although once there were only 13 years between eruptions. The last eruption was in 1918, so with a maximum of around 80 years between eruption… well, you do the math.
Hekla
Hekla has a height of 1491m, an age of 5.000-10.000 years and used to be known by people all over Europe as the gateway to hell, as there used to be so many eruptions there, many hundreds of years ago. Hekla is the second most active volcano and its eruptions have become more and more frequent over the last 50 years.
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As mentioned, Hekla is the second most active volcano in Iceland, only surpassed by Grímsvötn. Hekla, however, holds the first place if you compare the amount of lava and other debris from her eruptions.
Hekla doesn’t give nearly as much warning as Katla, and when there has been any warning at all, it has only been around an hour before the eruption.
Krafla
Located in the North of Iceland, not far from the sites of Mývatn and Námafjall geothermal area.
Krafla lies in a very active area, which has frequent, long periods of eruptions/activity all over it. The last of these active periods ended in 1989 – although even to date, seismic activity persists to some extent – after 14 years and 10 eruptions.
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Krafla’s history of activity is believed to cover around 200.000 years, although substantial information only exists on the eruptions of the last 3000 years or so. In the vicinity of Krafla is a large geothermal power station, utilising the energy of the volcano.
Krafla Geothermal Station
Located in North Iceland in the middle of Ódáðahraun is Askja.
Ódáðahraun is Iceland’s biggest lava field, consisting of lava from numerous eruptions, mainly in the last 10.000 years. The lava field is a massive 4.000 km2 in size and contains many mountains and craters, including a group of active volcanos known as Dyngjufjöll, and the Caldera in the middle, known as Askja.
Askja is around 50 km2 in size, with water covering a part of it, known as Öskjuvatn or Lake Askja. This lake is believed to be the deepest in the country, at around 224m in depth. Not a lot is known about Askja’s history, apart from the last 100-200 years. Askja has got a lot of craters, the most famous one being Víti, which literally means Inferno. Víti is 100m in width and is currently filled with water. Previously the water used to be literally boiling hot but now it is no more than a nice warm hot tub.
As for Askja’s eruptions, it’s main known eruptions are the ones that took place around 1875 – which resulted in thousands of Icelandic people moving over to Canada for a new start, after having had everything taken away from them – and the few smaller ones that have occurred in the last 100 years. The last eruption in Askja took place in 1961, but the last active period of Askja was between 1920 and 1930 with 7 eruptions in only 8 years.
Catalouge of Icelandic Volcanos
Hot springs
The most popular geyser area is Haukadalur, the Valley of hawks, the location of the original Geysir. Haukadalur is also the home of Strokkur, Iceland’s second largest geyser and the most frequently erupting one. Strokkur goes off every few minutes, whereas Geysir is a bit more unpredictable. The area also has a fair bit of small geysers, mud pools, hot pools and such.
Deildartunguhver, close to town of Borgarnes, is however the largest water yielding hot spring in the world, giving off around 180Liters/sec of 100 degree centigrade hot water. Part of that water is then used to heat up the towns Borgarnes and Akranes. The whole area of Deildartunga is all one big geothermal area and you will find, for obvious reasons, quite a lot of greenhouses there. Other popular geothermal areas are Krýsuvík not far from the Blue Lagoon, which has steam vents and mud pools, Námaskarð in East Iceland, which is similar but more colourful and full of boiling sulphur pits and Landmannalaugar in South Iceland, a beautiful area with a hot spring perfect for a bath. Not far from Landmannalaugar, you will also find a place known as Eldgjá, a volcanic fissure, the largest of it’s kind on Earth.
Glaciers
As the name suggests, Iceland has got the odd glacier here and there.
The biggest by far and best known is Vatnajökull, the Lake Glacier, the second biggest glacier in the world after Greenland´s ice-cap. The highest Icelandic peak is also a part of Vatnajökull and reaches 2119m above sea level.
Vatnajökull is located about 400km from Reykjavík, in South Iceland, covering a massive 8100 km2. Vatnajökull is the biggest glacier, not only in Iceland but it´s bigger than all the other glaciers of Europe combined. It is also one of the glaciers that are on top of active volcanos, …actually on top of many different volcanoes.
Dettifoss, the most powerful waterfall in Europe,
is located in North Iceland.