Katla volcano volcano
Volcano type Subglacial shield volcano
Location South Iceland, 63.63°N / 19.05°W
Summit elevation 1512 m (4,961 ft)
Last eruptions
920 AD, 950 AD (?), 1150, 1177, 1245, 1262, 1311, 1357, 1416, 1440, 1450, 1500, 1580, 1612, 1625, 1660-61, 1721, 1755-56, 1823, 1860, 1918, 1955(?), 1999(?), 1918
Typical eruption style
explosive basaltic and dacitic eruptions, voluminous lava flows.

Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is hidden beneath the Myrdalsjökull icecap.

The subglacial dominantly basaltic volcano is one of Iceland's most active and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods. A large 9 x 14 km subglacial caldera with a long axis in a NW-SE direction is up to 750 m deep. Its high point reaches 1380 m, and three major outlet glaciers have breached its rim.

Although most historical eruptions have taken place from fissures inside the caldera, the Eldgjá fissure system, which extends about 60 km to the NE from the current ice margin towards Grímsvötn volcano, has been the source of major Holocene eruptions. An eruption from the Eldgjá fissure system about 934 AD produced a voluminous lava flow of about 18 cu km, one of the world's largest known Holocene lava flows. Katla has been the source of frequent subglacial basaltic explosive eruptions that have been among the largest tephra-producers in Iceland during historical time and has produced dacitic explosive eruptions during the Holocene.

The home of the Katla volcano is Mýrdalsjökull glacier which is the southernmost glacier in Iceland and is almost 600 km2. It covers the upper part of a large volcano, the Katla caldera. Katla is about 30 km in diameter and the highest parts reach almost 1500 m a.s.l. In the center of the Mýrdalsjökull ice cap is the Katla caldera. It is oval in shape with the longest axis NW-SE and covers an area 110 km2. The highest points of the ice cap lie on the caldera rim and include Goðabunga, Háabunga, Austmannsbunga, Enta, Entukollar. Within the caldera the ice is hundreds of meters thick.

During the summer of 1999 some activity was noted within the Mýrdalsjökull caldera. On the night of the 18th July came a sudden flood in the river Jökulsá á Sólheimasandi. The source of the flood was meltwater from a depression formed simultaneously in the glacier surface, within the ice drainage basin of Sólheimajökull. After the flood existing depressions enlarged and crevasses were formed. The depressions became deeper during the summer and increased in number. The reason was increased geothermal activity. It is possible that there was a small eruption at the head of Sólheimajökull that formed a depression and caused the flood.

Katla erupted very powerfully in 1918 but there are evidence of smaller eruptions after that. Icelandic volcanologists are expecting another eruption in next few years so the Myrdalsjokull glacier and the Katla caldera are monitored quite closely. Just west of Katla and Myrdalsjokull glacier is another glacier, Eyjafjallajokull which is much smaller (50 km²).

The volcano Katla is subglacial and has a reputation as one of the most dangerous volcanoes of Iceland. Its peak reaches 1493 m in height and the extension of the glacier Mýrdalsjökull which lies over it reaches 595 km².

Mýrdalsjökull is the 4th biggest glacier in Iceland.

The crater of the volcano has a diameter of 10 km and the volcano normally erupts every 40 - 80 years. The last eruption took place in 1918, meaning scientists monitor the volcano very carefully. Since 930, 16 eruptions have been documented. The Laki craters and the Eldgjá are part of the same volcanic system, so it can be regarded as one of the most powerful in the world.

Before the National motorway no.1 had been constructed, people feared traversing the plains in front of the volcano because of the often occurring glacier runs and the deep rivers to cross. Especially fatal was the glacier run after the eruption of 1918.

In a Glance:

Eruption site	Year/century	Date	Duration (days)
Katla	1955	(small subglacial eruption)
Katla	1918	12 October	24
Katla	1860	8 May	20
Katla	1823	26 June	28
Katla	1755	17 October	~120
Katla	1721	11 May	~100
Katla	1660	3 November	~60
Katla	1625	2 September	13
Katla	1612	12 October
Katla	1580	11 August
Katla	~1500
Katla	15. century
Katla	1416
Katla	~1357
Katla	1262
Katla	1245
Katla	~1179
Katla	12. century
Eldgjá-Katla	~934
Katla	~920
Katla	Late 9. cent. or early 10. cent.

Tags: Katla Volcano