Laki (volcano)
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- This page is about the volcanic Laki craters, for other meanings of the word "laki" see Laki (disambiguation).
Laki (Icelandic: Lakagígar) is situated in the south of Iceland not far from the canyon of Eldgjá and the small town Kirkjubæjarklaustur.
This volcanic system, centering on the Grímsvötn volcano, was responsible for the biggest volcanic eruption on earth in historical times, in the form of a flood basalt. Between the glaciers of Mýrdalsjökull and Vatnajökull, there is an area of fissures which lies in a south-west to north-east direction. This area—including Eldgjá—produced the largest amount of lava ever produced in individual eruptions during historical times.
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[edit] The Big Eruption
On the June 8, 1783 a fissure with 130 craters opened explosively at first because of the groundwater interacting with the rising basalt magma. Over time, the eruptions became less explosive, with the style changing from Plinian to Strombolian, and later to Hawaiian with high rates of lava effusion.
The eruption, also known as the Skaftá Fires, produced about 15 km³ of basalt lava, and the total volume of tephra emitted was 0.91 km3 [1]. Lava fountains were estimated to have reached 800-1400 m in height. In Scotland, the summer of 1783 was known as the sand-summer, due to ash fallout in Scotland. The gases were carried by the convective eruption column to altitudes of about 15 km. The aerosols built up caused a cooling effect in the Northern Hemisphere, possibly by as much as 1 degree Celsius.
The eruption continued until February 7, 1784, but most of the lava was erupted in the first five months. Grímsvötn volcano, from which the Laki fissure extends, was also erupting at the time from 1783 until 1785.
[edit] Consequences
The consequences for Iceland were catastrophic. Cattle died because of poisoning, and the ensuing famine caused the death of many. There is also evidence that fluorosis caused by fluorine gas released during the eruption killed many others [2]. The population of Iceland fell by a third in the years following the eruption.
The parish priest Jón Steingrimsson grew famous because of his so-called fire sermon. The whole community of the small town Kirkjubæjarklaustur was in church. At the same time the town was endangered by a lava stream. But while the people were in church, the lava stopped not far from town. "This past week, and the two prior to it, more poison fell from the sky than words can describe: ash, volcanic hairs, rain full of sulfur and salt peter, all of it mixed with sand. The snouts, nostrils, and feet of livestock grazing or walking on the grass turned bright yellow and raw. All water went tepid and light blue in color and gravel slides turned gray. All the earth's plants burned, withered and turned gray, one after the another, as the fire increased and neared the settlements." (Rev. Jón Steingrímsson, Fires of the Earth, The Laki Eruption (1783-1784) ISBN 9979542446. Steingrimsson's autobiography has been translated into English as A Very Present Help in Trouble: The Autobiography of the Fire-Priest ISBN 0820452068.
