Eyjafjallajökull
View from the summit crater to the north -west, August 2013
The Eyjafjallajökull ( [ ɛɪja ˌ ˌ fjatl̥a jœkʏtl̥ ] ) (German island mountains glacier) is the sixth largest glacier in Iceland. It lies at the extreme south coast, west of the glacier Mýrdalsjökull in the community Rangárþing eystra, the greatest height is 1651 meters. Under the glacier of the same volcano is located with its own magma chamber that was active since the settlement of Iceland in the years 920, 1612 ( or 1613 ), from 1821 to 1823 and most recently in 2010.
- 4.1 Prehistoric eruptions
- 4.2 Historical eruptions 4.2.1 Skerin Ridge and the outbreak of the year 920
- 4.2.2 1612 or 1613
- 4.2.3 The outbreak of 1821-23
Name
The name Eyjafjallajökull (German island mountains glacier) is due to the so-called Landeyjar (German Malvinas ) ago. These are rocky elevations, island mountains, onto the sands between the mountains and the sea. They rise abruptly from the flat plain of sand completely out like islands in a sea, and were indeed often in earlier times islands before the glacier runs the coastline moved in volcanic eruptions, with its sediment load into the sea.
The glacier
The ice cap of Eyjafjallajökull covers about 78 square kilometers and extends to a height of about 1000 meters down.
The highest of the peaks that protrude on the edge of the summit caldera as small nunataks from the glacier, is the 1651 meter high Guðnasteinn. Other well-known peaks are Goðasteinn, in the north of the main crater and Hámundur in the south of the main crater.
Some outlet glaciers descend down to the valley floor in 150-200 m above sea level. The most important of these outlet glaciers are Steinholtsjökull Gígjökull and extending in the direction of the current Markarfljót north. The name of the latter Auslassgletschers means in German crater glacier and goes back to the fact that the outlet glaciers emanating from a large notch in the summit crater. Gígur is the Icelandic word for crater. The steep and rugged outlet glaciers extends approximately 1200 meters down into the valley of the Markarfljót. The Gígjökull has pushed high moraines on the valley floor. By melting of the ice, a glacier lake had formed, called Lónið. In the volcanic eruption in April 2010, the glacial lake was completely filled by volcanic ash and sediments and disappeared.
The volcano under the glacier
W1
Eyjafjallajökull
With not only the Eyjafjallajökull glacier, but also the entire volcanic massif with several smaller mountains is referred to below.
Shape of the volcano
The volcano belongs to the Southern and Eastern volcanic zone of Iceland. , Where the volcanologists are doing about the type of volcano does not quite agree. Þorleifur Einarsson numbered him among the stratovolcanoes, Þór Þórðarson speaks of a shield volcano and Ari Guðmundsson Trausti describes the volcano as " flat elongate volcanic edifices ."
The caldera of the volcano has a diameter of about three to four kilometers. The volcano associated columns swarms extend their craters in west-east direction over approximately 30 kilometers. Some other craters were formed in March 2010 during the recent outbreak at Fimmvörðuháls.
Rocks, lava and ash
The oldest rocks of Eyjafjallajökull are about 700000-800000 years old. These are so-called transitionale basalts (transitional type between alkali basalt and Tholeiitbasalt ), but also higher differentiated rocks such as dacite. The basalt rock types on this volcano were as hot lava around 1200 ° C and contain a liquid SiO 2 content by approximately 50 percent and shares of Al2O3, MgO, FeO, K2O and Na2O. The molten lava cooled to basalt. Similar chemical compositions have the lavas of the volcanoes in Hawaii and Australia in Undara National Park.
Eruption history
The volcano under the Eyjafjallajokull has achieved a about 800,000 years of eruption history. Since the acquisition of land from 870 AD he was before 2010, however, only four active and therefore not one of the most active volcanoes in Iceland.
Prehistoric eruptions
During the ice age twelve different outbreak phases can be identified, of which six phases to interglacial periods, and six more on glacial periods.
During the latter about hyaloclastite and pillow lava, which also make up part of the volcanic building emerged.
During the ice-free periods, lava piled up. These are, for example, clearly seen in the former sea cliffs on the south side of the mountain.
After the ice age occurred about 10,000 years ago, two effusive eruptions in which lava flows of Hamragarðar and Kambagil were produced.
Historical eruptions
Only five known outbreaks occurred, however, since the settlement of Iceland. The first happened 920, the second eruption was 1612/13 instead, another in the years 1821-23. In the spring of 2010, two eruptions occurred, the first in March on Fimmvörðuháls, the second from mid-April at the summit caldera.
Skerin Ridge and the outbreak of the year 920
In Skerin Ridge is a radial fissure, which is found in the north- west of the summit caldera of Eyjafjallajökull. The back has a length of about 4.5 km and a width of about 100 m.
Geological studies of the traces of glacial streams, which have their origin in this back, indicate a formation during an outbreak under the glacier in the 10th century. Global warming and the consequent retreat of the glacier allowed a more detailed analysis of the structure of this ridge in particular in relation to the rapid cooling of lava through the glacier ice.
The results show that the back has built up mainly from trachitischem rock (0.043 km ³ ), although to a lesser extent also of basalt rocks and intermediate tephra layers ( Trachyandesit ) is (0.012 km ³ ).
The outbreak started obviously with the construction of a cinder cone on the northwest end of the ice-free column and a phreatomagmatic eruption in the ice-covered southeastern end of the column, which left a Tuffwall from the same rock. The outbreak was a mixed eruption, simultaneously explosive and effusive, where a series of vents along the fissure lavas flowed from trachitische that were rapidly cooled by the melting waters of the glacier. The series ended with a strombolian eruption phase.
Petrological studies have shown that just before the outbreak obviously been a mixing of magmas of different composition and a basalt intrusion had triggered the eruption of acidic rock.
It was also found traces of at least one older and undated outbreak at the same eruption column, which had produced a Basaltlavafeld north thereof.
1612 or 1613
From this outbreak little is known.
A traveler from Moravia named Daniel Vetter described in the Winter 1612 and 1613, the very precise date is not fixed, an eruption of Eyjafjallajökull. For a while we did not consider his report credible or transferred the description of an outbreak of Katla because running at this time Mýrdalsjökull and under the same name Eyjafjallajökull Eyjafjallajökull.
Vetter described the events as follows: Three days was terrible roar and roar could be heard from the mountain. The sound reminded him doing shots at extremely large guns. Finally, the mountain blazed up, especially in the summit area. Furthermore, it is a lot of volcanic ejecta descended on a lake at his feet and have these refilled within a short time dried up and burning hot lava and rock fragments.
Further evidence is found in the Skarðsannalen. There, the eruption is described as follows: " Suddenly the Eyjafjallajökull jumped on the east side to the sea front, there came highly fire that could be seen almost everywhere north of the country. "
The outbreak of 1821-23
The penultimate outbreak occurred from December 1821 to January 1823. There are four million cubic meters were promoted dark gray, fine-grained dacitic ashes which are found mainly in southern Iceland. This still rather small outbreak taught at some damage. In particular, the ash was rich in fluorine, which hurt the cattle. Also, the outbreak caused small to medium sized glacier runs, especially in the Markarfljót, but also in the river Holtsá.
The outbreak started on 19 and 20 December 1821 an explosive phase, which lasted several days and strong ash fall was mainly in the populated areas in the south and west of the volcano result.
By June of the following year the eruption stopped, without being perceived, however, particularly in the settlements, apart from gestiegenem water level about the Markarfljót.
From the end of June 1822 was again followed an explosive phase, the explosive eruptions probably came in each series. The eruption sent a cloud among others in considerable heights. Ash fell in Eyjafjörður in Northern Iceland, but also on the peninsula Seltjarnarnes on which is a part of the City of Reykjavík.
From August to December 1822, the outbreak seems to have been less strong. Nevertheless, livestock died in Eyjafjörður of fluorine poisoning and in the Holtsá on the south side of the volcanic massif presented one small glacier runs permanently. In Markarfljót on the north side, it was found a considerable glacier run. However, the source location will not open up the exact date.
1823 some men ventured to the Eyjafjallajökull to inspect the craters in greater detail. They found an eruptive fissure just northwest of the summit Guðnasteinn. The men were concerned that the mountain could fall apart because the column was very close at the top edge and was only a thin rock wall between her and the abyss.
Following the outbreaks, it was found that the mountain had changed, and a significant depression was created in summit area, where he had previously worked rather flat.
In the spring of 1823 the neighboring volcano Katla erupted under the Mýrdalsjökull simultaneously flowed from the summit area of the Eyjafjallajökull again more steam, especially on the main eruption column.
Eruptions in 2010
Starting with the March 20, there were several eruptions of the volcano with a large emission of ash. Air traffic over northern and central Europe had to be set in many parts and for several days as a result.
Seen first column from the southeast, August 4, 2010
Eruption at Fimmvörðuháls, April 4, 2010
Hrúnárgil 2009. During the first series of eruptions of 2010, a lava fall spilled into the gorge.
Eruption in the summit region 1 May 2010
A block of ice on the sandy plain of Markarfljót, remnant of a glacier run, photo by May 1, 2010
Gígjökull 19 June 2010
Play of colors Fimmvörðuháls March 26, 2010
Correlation of Eyjafjallajökull and Mýrdalsjökull
In the last three eruptions in Eyjafjallajökull volcano system in the years 920, 1612 and 1823 and broke at the same time or a little later, also the neighboring volcano Katla under the Mýrdalsjökull from. Thus, it is assumed a time-action connection between the two volcanoes. On Fimmvörðuháls (German, saddle of five stone men '), the transition between Eyjafjallajökull and Mýrdalsjökull was often found some seismic activity in recent years.
Páll Einarsson geophysicist draws attention to the need to Katla, the volcano under the glacier Mýrdalsjökull to monitor closely because the eruption under the Eyjafjallajokull could trigger another in the Katla in March 2010.
Climbing at Eyjafjallajökull
The first ascent was Sveinn Pálsson on August 17, 1793.
The simplest option is to climb from the pass Fimmvörðuháls over the ridge to Glacier. From the Útivist - shelter (~ 1050m ) from the summit crater can be reached in about 3 hours. An ascent is only possible in good weather, as the summit region on cloud height is. In poor visibility, the orientation of the glacier field and the detection of crevasses is almost impossible.
Ari Guðmundsson Trausti describes as a alternative climb tour from north- north-west. Direction, starting at the runway for Þórsmörk, over the Grýtutindur. However, it is questionable whether this route is still accessible after the eruption of 2010.
Eyjafjöll
As Eyjafjöll (German, island mountains ') is the whole of the southern flank of the volcano Eyjafjallajökull massif from Seljalandsfoss in the West referred to the glacier flow Jökulsá Sólheimasandi in the east. The Eyjafjöll consist of steep, partly several hundred meters high rock walls, and some foothills which about 10,000 years ago, initially formed a cliff after the end of the last ice age, and now have countless waterfalls. By postglacial land uplift by about 60 m of the coast line is now postponed by five kilometers to the south, and it has a coastal plain gebildet.Dies is particularly evident at the waterfalls Skógafoss and Seljalandsfoss. The name Eyjafjöll is because this side of the mountain seen from the Westman Islands from clearly stands out from the silhouette of the main island of Iceland. The area at the foot of the mountains ( undir Eyjafjöllum = dt, under the island mountains' ) is determined by the high mountains to the north protected from cold winds, whereas mild bring moist southerly winds much precipitation, giving the area the mildest and most fertile heard throughout Iceland and spring often keeps weeks before the wider area catchment. Through the past as cliffs, the mountains above in the lower region by ocean surf in the soft rock broken small caves, the most famous of the Paradísarhellir (Eng. Paradise Cave) is. You should have been in the 19th century the background of an exciting love story. In the Icelandic writer Jón Trausti wrote the novel Anne of Stóra -Borg.
Þórsmörk
On the north side of Eyjafjallajökull from the valley of the rivers Markarfljót Krossá and the lush forested ridge Þórsmörk is limited.
Trivia
- The Boeing 757-200 Icelandair with the registration TF - FII is named after the volcano.