under the centre of the Vatnajokull Ice Cap, is a large central volcano
about 45 km from its western edge and 50 km from the northern one.
The 35 km², ice filled caldera is usually the only conspicuous
part of the volcano.
Eruptions are and have been frequent, but some of them do not
endure long enough to melt all the way through the thick sheet of ice.
Geothermal activity keeps some areas at the caldera’s edges ice
free, depending on their capacity each time.
The caldera is partly surrounded with precipitous, mostly
hyaloclastite mountains, and depression in the landscape under the ice.
During the short period of time scientists have had to inspect
and research the area, the flood waves rushing underneath the ice have
taken two courses depending of the location of the volcanic or
A minute part has sought outlets to the west and caused floodings in River Skafta, but
the greatest volume has found its way through toward east
and then been diverted by solid mountains toward south.
The caldera empties, when the water level has risen high enough
to lift the ice sheet above.
The last major floodings (glacier burst) were caused by the 1996
eruption to the west of the main volcano, when road and bridges
alluvial plain Skeidararsandur were damaged.
oldest source mentioning the Grimsvotn Area is a letter from
Skalholt’s Schoolmaster Olafur Einarsson, but the area was lost for
decades for the lack of communications across the ice cap.
The annals mention eruptions in unconfirmed areas of the
interior, which makes it difficult, if not impossible, to locate them.
Two Swedes, Hakon Wadell and Erik Ygberg, found the area in 1919
and called the volcano “The Swedish Crater”.
In 1934 in spring the volcano erupted and offered the first
opportunity for modern man to witness and register its behaviour
At that time the geologist of the expedition confirmed by reason
the rediscovery of the ancient Grimsvotn.
The Swedes, however, are remembered by the naming of a nearby
mountain, “The Swedish Peaks”.
renowned, late geophysicist and geologist, Sigurdur Thorarinsson,
studied the documentation and old sources to reach the conclusion of 21
certain and almost certain eruptions of the volcano during historical
The first was considered to have taken place in 1332.
Glacier bursts almost always were the results of the eruptions,
but they also happened in-between because of the constant geothermal
The Glaciological Society was founded in 1950, and since then
expeditions have been sent for research purposes to the Grimsvotn Area.
This area has been watch closely during the last few decades.
In 1955 the GS built a hut in Jokulheimar at the western edge of
the ice cap and two years later another one on the top of one of the two
Common travellers are welcome to use those huts upon prior