Krafla Caldera - Planning a Trip in Myvatn and Krafla

Krafla is a volcanic area in the northeast of Iceland, and one of Iceland’s largest lava lover lures. Craters, cones, pools and geothermal heat – Krafla has it all.

Krafla is basically a 10 kilometre wide caldera which contains volcanoes – the latter containing a small azure-coloured geothermal pool and the former containing Iceland’s deepest lake. Both are inland in the Highlands and only accessible in the height of summer.

But the Krafla area starts close to Lake Mývatn and only a few minutes’ drive from Reykjahlíð village. At this convenient nearest point, accessible in any car, you will find the remains of the lengthy mid-80s eruption. This means a large, relatively flat area to explore and the opportunity to get up close and personal to spiky lava, hot pools, bubbling mud, ‘eggy’ sulphur smells and the expansive power station in the area.

The large Krafla geothermal power station takes full advantage of the volcanism in the area and its run-off is used in the lovely Mývatn Nature Baths. The site is also home to the first drill hole of the fascinatingly exciting Iceland Deep Drilling Project.

The project looks to harness the power of “super critical” water in energy generation and this involves drilling down to the lava where large quantities of water can quickly be heated to over 400°C. The project aims to drill around 4 km below the surface – but at Krafla the scientists and engineers hit lava at just 2,500 metres. That’s shallow!

Krafla is a sensitive site and is easily damaged by people walking around and exploring. That is the reason the site is so well marked with footpaths and trails. These, combined with the good car park and bathroom facilities make Krafla a good place to go hiking with children and people with somewhat reduced mobility. The paths may be suitable for wheelchairs in good weather, although they can get soft and muddy in wet conditions.

Krafla is the best place to see first-hand where Iceland comes from. The whole country used to look like this at one point – as in fact did almost every country if you look far enough back into prehistory. It makes a good contrast with places like the Reykjanes peninsula down south, which features the same sort of landscape, except a few thousand years older. The difference is at once both stark and surprisingly little.

One thing is for sure: we all owe our lives to volcanoes and given long enough, Krafla will develop into remarkably fertile soil. But none of us will be alive to see that…

Krafla Geothermal Power Station

Development for harnessing of geothermal steam at Krafla, near Lake Mývatn in north Iceland, began with trial boreholes in 1974. Construction work commenced in the summer of 1975. The powerhouse and other structures were designed for two 30 MW turbines.

The station was initially designed and built for the Icelandic State and was run by the Krafla executive committee and later taken over by the State Electric Power Works. In 1985 Landsvirkjun purchased the Krafla station from the State.

Various initial difficulties were encountered in exploration and drilling for steam, largely due to seismic and volcanic activity which caused corrosive magma vapours to enter the geothermal system, destroying the borehole linings. A series of nine volcanic eruptions began in the vicinity of the station in December, 1975 and lasted intermittently until September 1984. Seismic and volcanic impact on operations at Krafla has been gradually diminished since then.

In 1996, Landsvirkjun decided to complete the install action of the second unit. Drilling for steam began immediately using improved drilling technology which has proved highly successful. Electricity production from the second unit began in November 1997, and since late 1998, the Krafla station has been operated with full capacity of 60 MW, as originally planned.

Get there by bus from Mývatn

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18/6-10/9 Daily	18/6-10/9 Daily	From To	SBA-NordurleidTimetable Tel: 553-5999 sba@sba.is
08:00 08:15 x	11:30 11:45x		ReynihlidKrafla

Berglind Rós
Iceland24
April 2015

Geology of Iceland: Ice and Fire

Volcanic activity  

Iceland was formed from volcanic eruptions on the Mid-Atlantic ridge. Iceland was formed for about 24 million years. Iceland is the only place where you can stand on the ridge on dry land. That makes Iceland very special and a popular place for geologists to visit and do their researches.

The ridge separates the Eurasia and the American systems which are always going further away from each other. And that can trigger volcanoes or earthquakes. That, along with the hot spot that is under Iceland, makes the country highly active in volcanic activities. The hotspot is probably the reason for the island’s existence because the ridge alone could not have made such a large island. But if Iceland had only been formed by the hot spot it would like a lot similar to the Hawaiian islands. The hot spot is now situated under Vatnajökull.

As an example of Iceland's extreme volcanic activity, 1/3 of the magma that has erupted on the earth for the last 10.000 years came up in Iceland. And that is pretty much for such a small country. In Iceland, a volcano erupts every four years in average. The last eruption was in Grímsvötn on glacier Vatnajökull in the beginning of last November (2004). But that was only a small eruption. But we could see the smoke from it from our school.

Apart from the Mid-Atlantic ridge there are other fracture zones. You can see the fracture zones and the position of the Mid-Atlantic ridge on the picture above.

The picture is copied from the Icelandic weather web page www.vedur.is.

The red dot is a mark for the hot spot and the blue line is the Mid-Atlantic ridge.  The fracture zones are beside the Mid-Atlantic ridge in North and East.

Main volcanoes

In Iceland there are a lot of volcanoes (as maybe mentioned before). Some of them are greater and more famous than the others. Most of them are situated on the Mid-Atlantic Ridge but some of them are on the fracture zones.

The most famous volcano in Iceland, and one of the most famous in the world, is Hekla. Hekla is situated in the south of Iceland. Hekla has erupted 20 times since Iceland was settled and the last time she erupted was in the year 2000.

Although Hekla is the most famous, the most active one is Grímsvötn. Grímsvötn is situated in the middle of the Vatnajökull glacier. And as was mentioned before, Grímsvötn last time erupted in November 2004. Apart from Grímsvötn there are a lot of other volcanoes under Vatnajökull glacier. In Grímsvötn there is the most geothermal area in Iceland. And it is under the glacier. With every eruption in Grímsvötn there follows a glacier burst that comes out in the rivers that lie out from the glacier to the south coast of Iceland.

Can you see now why Iceland is called the land of fire and ice?

It is also interesting that in the neighbourhood of Reykjavík and the Reykjanes, where the majority of all people in Iceland (almost 200.000 people) live there are at least 5 volcanic systems with series of volcanoes that can all still erupt. And if we ought to calculate all the people in Iceland who live 50km or closer to a volcano system we would be dealing with a lot larger number.

Glaciers  

Iceland is widely known for its many glaciers. Some, if not most people have heard that the largest glacier in Europe is there. It is called Vatnajökull glacier (Water glacier). Iceland also has some other large glaciers like Langjökull (Long glacier), Hofsjökull (Temple glacier), Mýrdalsjökull (Swamp Valley Glacier), Drangajökull (Pillar of rock Glacier) and some other smaller glaciers. 11% of the whole country is covered with glaciers.

Glaciers form where more snow snows in the winter than can melt in the summer, so the existence of glaciers depends in the temperature.

Vatnajökull glacier, along with most of the other larger glaciers began to form about 2500 years ago. It began as little glaciers on three mountain peaks and slowly united with each other.

There are five icecaps in Iceland, Vatnajökull, Langjökull, Hofsjökull, Mýrdalsjökull and Drangajökull. From them some smaller glaciers “crawl” (glacier tongues). For a long period of time they can form valleys and fjords.

If Vatnajökull glacier would be swept away in an instant it would only form again on the highest mountains if the weather would be similar as it is for a long time.

On the other hand, the land under the glacier and near it would arise a lot. The area under the center of it would rise about 100 meters and about 50 meters under the edges. The area where we live in and the school is located in would rise about 20 meters and in 50 kilometers distance, the land would rise less than 5 meters. But that scenario would be very unlikely.

Some people believe that a scenario like that would have great influence on volcanoes under the glacier and lead to an era of a lot of volcanic activity where some volcanoes that are under it now could erupt at the same time.

Earthquakes 

In Iceland, a lot of earthquakes occur every day. You can see a map where the earthquakes of the last 48 hours have occurred in Iceland on the Icelandic weather page.

The last two large earthquakes occurred in Iceland in the year 2000. They were between 6,5 and 7 on Richter scale. Earthquakes in Iceland don’t go over 7 on Richter scale because of some unknown reason.

Peter, Iceland24
June 2014
Source: Water and Fire