Volcanism

Iceland lies on the Mid-Atlantic Rift. On the west side of the rift is the North American Tectonic Plate and on the east side the Eurasian Tectonic Plate, and in the Iceland area they now move apart at a speed of two millimeters per year. So the Earth's crust is stressed and from time to time it cracks, often opening a way for the glowing magma below. The picture shows crudely where the (forked) rift runs across the island.

However, a major reason for large amounts of melted rock flowing to the surface right here, is the Iceland plume or hot-spot, an upwelling in the hot soup below. This is what created Iceland. 17–20 million years ago the first volcanic mountain emerged from the sea, and the island has continued growing ever since. The latest contribution, in terms of emerging from the sea, was Surtsey in 1963. That island was only 2.7 km², and half of it has already been eroded away.

Þingvallavatn is the largest lake in Iceland, 84 km². This area is used to illustrate how the island is being torn between the two tectonic plates; it's littered with tears. They don't extend down to the scorching interior though.

Þingvellir, the area of the old thingstead, is also rich in surface tears, some large like this one.

Þingvellir. Some cracks are filled with water. (And it isn't boiling!)

Stóri Geysir (Great Geyser) – that gave them all a name – hasn't been its former self for more than half a century, when tourists through rocks into it to set it off. But its close neighbor Stokkur is reliable, spouting hot water every few minutes as shown. As you might know, this phenomenon is similar to boiling clean water devoid of air (bubbles): Vapor bubbles can't form without 'help', microscopic vapor bubbles require an enormous internal pressure to expand because of the surface tension, so the water gets superheated. When (with some obscure kind of help) a vapor bubble finally forms, it expands almost like an explosion.

Stokkur from a distance, a typical shot, just a few seconds late. Close by are several small hot springs and vapor vents. This site is found less than 50 km by road east of Þingvallavatn.

What a tourist can see of the Deildartunguhver hot spring in the Reykholt area. It's the largest thermal spring on the island, yielding 180 liters of boiling water every second. And it is of course used for heating; there are pipelines to Akranes and Borgarnes, and to greenhouses in the neighborhood.

Deildartunguhver continued. Heating by water from thermal springs and boreholes is common in Iceland. In minor towns (as are most towns in Iceland) the hot ground water is fed directly to the hot water taps. There you can wash and shower enjoying a quite noticeable smell of Hell, or more soberly, sulfurous compounds. In the Reykjavik district the hot water for house heating and washing water are carried by separate tubings; the washing water is clean (close to) surface water heated by geothermal water.

The Kerið volcanic caldera in the Grímsnes area is about three thousand years old. This 170 × 270 meters elliptic crater is 55 m deep. In 1986 the well-known singer Björk held a concert on a raft in the middle of the lake. Yes, we observed fish feeding on surface insects.

Immediately west of Vatnajökull and about 30 km north of Kirkjubæjarklausturt, lies Laki (or more correctly, Lakagigar, Laki craters), a 26 km long crater row, created by the enormous eruption between 8. June 1783 and 7. February 1784. This resulted in large lava fields ('rhaun'), totally 565 km². The picture is taken in the part of it called Eldrhaun (=fire-lava) southwest of Kirkjubæjarklaustur where the Ring Road runs through. It's now largely covered by moss with occasional small shrubs and small patches of other growth.

Tapestry – Selfosskirkja

The Laki eruption was one of the largest worldwide in the second millennium. The emitted sulphur dioxide spread over Europe and North America, creating a thick fog that induced respiratory sickness and many deaths, especially among those that laboured in the fields. The lower atmosphere pollution subsided during the autumn, but a lot of sulphur dioxide had been blown high into the stratosphere of the northern hemisphere, transformed into a haze of sulphuric acid droplets. This haze reflected parts of the sunshine, causing an extremely cold winter (e.g. ice on the Mississippi at New Orleans). The next few winters and summers the weather was not only cold, it was abnormal, and the crops were low or even failed completely, causing famines around the hemisphere. In India and North Africa the climatic upset caused a severe drought. Some researchers have estimated the total number of additional deaths to be as much as six millions. Also, it has been suggested that the suffering of the French peasants initiated the Revolution starting in 1789. The volcanoes also spewed out lots of hydrofluoric acid which is absorbed by the vegetation. In Iceland 4/5 of the sheep and more than half of the cattle and horses died from fluorosis, and more than 1/5 (about 10,000) of the population died from starvation, maybe also fluorosis. A third of the Icelandic population lived by fishing and had plenty of fish to eat, and even exported fish during the crisis, but sadly there was no effective administration present to share the food with the farmers. (Probably this was before administrations were supposed to care about the citizens; anyway, the King was far-off in Denmark.)

View from the north side of Mývatn towards southeast. Beyond the other shore Hverfell or Hverfjall is an evident landmark. It's a roughly 2500 years old tephra cone or tuff ring, more then a kilometer wide, rising some 460 meters above the surrounds. One of the two tracks to the rim of the crater (which you are required to use) may be seen in the (large) picture.

Hverfjall or Hverfell viewed from the southwest peak. It looks like being made of loose gravel, both outside and inside.

Dimmuborgir, an unusual lava field at the east side of Mývatn. It was created 2300 years ago when lava from an eruption to the east flowed through a small lake causing intense boiling and leaving solidified pillars when it continued to lower grounds. A network of footpaths runs through this area, and you may spend hours here if you want to see most of it. (Dimmu-borgir means Dark-castle.)

Kirkja (the Church) is the most famous lava formation in Dimmuborgir. It should be possible to hold a Mass for a congregation of at least half a dozen inside the church, without organ music though. The large image size page includes a picture of the interior.

There are also strange lava formations at Mývatn west of Dimmuborgir. The picture is taken from the peninsula Höfði (= head[land]). Roughly fifteen kilometers towards the south, Bláfjall (= blue mountain), altitude 1222 m. A former owner of the peninsula spent his summer holidays planting trees and herbs here, and his widow donated it to the county. Paths run through the forest and you can enjoy trees, flowers, birds, lava formations and great views – if the midges aren't too annoying (Mývaten means Midge-lake, you know).


Klasar means 'clusters', here of lava pillars. You may watch them if you take the path around the part of the Mývaten shore called Kálfaströnd (=calves-shore). Höfði park is seen on the other side of the bay.

The lava flow that caused the pillars in Dimmuborgir and elsewhere in the area, also dammed up the present Mývatn, in a way replacing a previous lake. Mývaten is quite shallow, the average depth is about 5 meters.

The picture shows a few of the pseudocraters of Skútustaðagígar (Skútustaðir Craters), the largest crowd of them at Mývatn. They were created 2300 years ago by trapped water that exploded under the hot lava flow mentioned above. They come in assorted sizes and may be seen in various places near the lake. In the background the Skútustaðir village and the mountains Bláfjall (1222 m) (left) and Sellandafjall (988 m).


East of Mývatn (discernible top left in the large picture), the crater Víti, meaning Hell (also Stóra Víti, Big Hell), 320 m wide, was formed by an explosion in 1724. This was the start of a series of eruption in the area (the "Mývatn fires"), ending in 1729; that year the Reykjahlíð village (excluding the church) was destroyed by the lava flow. Víti lies on the foot of the great volcano Krafla. The whole active area is called the Krafla area. The last eruption here was during 1975–84 (the "Krafla fires"). The area is littered with signs of volcanic activity, like steam vents and hot mudpots.

Construction of a geothermal power station started in 1973, and holes were drilled to a sufficient depth. The most spectacular part of the story is the explosion in a borehole; pieces of the drilling rig was found up to three kilometers away. Nobody was injured, and the resulting crater was named Sjálfskapar Víti (Self-created Hell). In the picture, behind the crater, excess steam from a borhole is escaping, sounding like a jet engine at full throttle.

The oldest Krafla power station. In spite of the 1975–84 eruption the first power station started operating in 1978 and more boreholes and a second turbine was added in 1996. They had several problems to solve on the way, one was a water temperature of 350 °C, much higher than expected, another was the corrosion of metals caused by sulphur dioxide and carbon dioxide.

Hverir is a geothermal area at the east slop of the low mountain ridge Námafjall, east of Mývatn, a few kilometers south of Krafla, just south of the Ring Road. Among other hot and stinking attractions it contains a lot of steam vents, as shown here.

Hveir also exhibits these boiling mudpots. It's an excellent idea to watch your steps.

Jarðböðin (literary 'the Earth-baths') on the west slope of Námafjall, a couple of kilometers east of Mývatn (discernible top left), "is like the Blue Lagoon, only better", according to what I was told locally. Well, it's smaller, but there seems to be nothing wrong with it, and it's newer, it opened in 2004. If you look closely (at the large size picture) you may see a lady in the water waving to the photographer. The latter had ventured further up the barren and dusty Námafjall slope, looking out for hot spots of course.

The Blue Lagoon ('Bláa Lónið'), one of those places tourist feel they have to visit. And since it lies near Keflavík, and Reykjavík for that matter, it should usually be possible. This was on a windy and rainy day. Maybe you'll prefer to go there in far worse weather, like a blizzard or just a heavy snowfall?

Reykjahlíð and Mývatn seen from the east.

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Maybe this Iceland section should contain only one subsection: Volcanism. Because it is evident almost everywhere on this young island.

However, I regret there are no active volcano pictures. The Eyafjallajökull volcano went to sleep a week before our arrival. It's a comfort that this eruption, compared to the Laki eruption (see above), was in the firecracker category (please don't cite me to those airline guys).

updated 2012-03-30