Aerial view of Krafla and Víti crater with a number of boreholes
View from Námaskarð on the Krafla in Hintergrundbdep2
In the Krafla [k ʰ rapla ] is a volcanic system of approximately 100 km in length in the north of Iceland. The eponymous central volcano of 818 m height dominated with numerous craters, the Mývatn region.
- 4.1 Geothermalkraftwerke
- 4.2 Deep drilling at a central volcano
- 7.1 Photos and Videos
- 7.2 Geological Background
- 7.3 Nature Reserve is at the Krafla
The Krafla volcanic system consists of a central volcano with Einbruchscaldera and an elongated fissure swarm.
The latter is about 10 km wide and extends for about 100 km in the NS direction. At the southern end there is, for example, the panel volcano Selfjall. In the north of the system extends to the fjord Öxarfjörður.
The central volcano Krafla itself, a magma chamber below the at 3 km depth, consists mainly of a large caldera (10 km in diameter).
He is over 200 000 years. The volcano built by eruptions under ice as well as in the air, ie Activities were also detected during cold periods of the Ice Age.
The caldera itself originated with enormous explosive eruptions where magma chambers collapsed in itself, more than 100 000 years ago.
At the outer caldera rim are, inter alia, to two rhyolitic volcanoes panel, Hlíðarfjall and Jörundur that originated in SiO 2-containing eruptions under glaciers during the Ice Age.
Outbreaks after the Ice Age
The neuzeitlicheren eruptions began with the formation of Tuffrings Ludent more than 6600 years ago. Soon after, followed by further outbreak series in nearby columns and also on Námafjall.
The older lavas Laxá
The vast so-called elders Laxá lavas flowed about 3800 years ago on the territory of the Krafla volcano, however, were created during outbreaks of belonging to the adjacent Fremrinámur system shield volcano Ketildyngja. Here, the outflow of the river Laxa í Aðaldal was clogged so behind it to form the Lake Mývatn began (see also the origins of the lake Þingvallavatn ). The lavas then followed the valley of the Laxá over 50 km in length, until they finally poured into the bay Skjálfandi.
The tuff ring Hverfjall owes its origin to a hydro- magmatic explosion, ie the meeting of magma with groundwater, in connection with a recent series of eruptions about 2800 years ago.
On June 22, 2011 Hverfjall was put together with Dimmuborgir under protection.
The younger lavas Laxá
Not far from there was another outbreak Hverfjall series in the crater row of Lúdentsborgir about 2000 years ago. This produced the so-called Younger Laxa lavas.
This series of eruptions is at the origin of today's picturesque appearance of the area around Mývatn. For example, this was a lava lake, which today form the residues Lavalabyrinth the Dimmuborgir, as well as the numerous pseudo craters, both as islands in the sea and on land about Skútustaðir.
Mývatn fires and Víti Crater
In the 18th century there were again larger outbreak series after Krafla had rested about 1000 years. This was later called Mývatn fires ( Isl Mývatns Eldar ).
These were to unrest and eruption phases over 5 years ranged from 1724-29.
On May 17, 1724, the unrest episode began with another hydro- magmatic explosion that formed the crater Víti. Víti means in Icelandic hell There is a second crater of that name south-east of Myvatn to Askja. In Víti today is a maar, which receives its turquoise color by silica algae.
Repeated eruption phase lasted until 1729. The outbreaks also included the area of Leirhnjúkur and even the immediate environment of Reykjahlíð, where you could see at Bjarnaflag lava fountains.
The then existing here three farms had to be evacuated. However, the church, which stands on a small hill, was preserved.
1746 was followed by further outbreaks.
During this phase of unrest, there were also strong earthquake and Riftingphasen.
The date last eruption of the Krafla series took place from 1975 to 1984, the so-called Krafla Fire ( Isl Kröflueldar ).
The name indicates that the majority of outbreaks now in the Krafla caldera itself held and there especially on the volcano and Leirhnjúkur. The lava fields there are still warm and Degas, as well as the peak and the high-temperature region with its solfataras, mud pools and fumaroles at its foot.
It could be measured earthquakes up to a magnitude 4. The floors throughout the system deformed, it came to grave education, inflation and deflation of the caldera floor. Overall, the fissure swarm widened to 900 mm while the 9 -year-long unrest phases.
Scientists were able to demonstrate in this way that rifting and spreading are not a continuous process but have flares (see plate tectonics ).
High temperature area Hverarönd
Solfataras and mud springs characterize the nearby high temperature area Námaskarð or Hverarönd on the east side of the Kraflasystems belonging volcano Námafjall. It is also part of this volcanic system.
Use of geothermal energy
Since 1977, one uses the geothermal energy by means of two Geothermalkraftwerke, Bjarnaflagsstöð at Reykjahlíð and Kröfluvirkjun directly on the central volcano Krafla.
Deep drilling at a central volcano
In deep wells in the Krafla caldera, a research team in 2009 came surprisingly in depth 2,100 m on rhyolitic magma.
One wonders if one could not use the magma more layers of water for energy production.
On the other hand, conservationists contact such as the journalist Ómar Ragnarsson against the deep drilling because they are of the view that the technical installations will reduce the beauty of the landscape and also cause considerable noise.
Hiking at the Krafla
The area in the region of the central volcano is considered one of the most interesting hiking areas in Iceland. It is also one of the most developed with trails.
Here, you can choose from a wide variety of options easy and medium difficulty.
Easy walks lead around on mostly wide -made paths through the remnants of the lava lake at Dimmuborgir or order and the pseudo craters of Skútustaðir as well as by the high temperature area Hverarönd or on the Víti crater. Average difficulty have about tours on the Vindbelgjarfjall and around and on the Leirhnjúkur and from there down to about five hours to the lake after Reykjahlíð.