The Island Mountains’ Glacier (1,666 m) or rather its mountain range is among the highest of the country, 5500 feet (1666m).  It derives its name from the Island Archipelago off the south coast, The Vestman Islands.  This mountain massif is actually the result of continuous eruptions during thousands of years and a vast crater on top has probably been active a few times during historic times of this country.  The only documented eruptions took place in the years 920, 1612, which was seen all the way to the northern part of the country, and during the period 1821-23.  Both eruptions caused at least damage to property by glacier bursts (floods) and ash fall.  The latter caused a three hours’ flooding of the wide valley floor north of the mountain.  Before and around the turn of the last century, an increased earthquake activity and escaping gasses were watched closely.  This volcano, and many others, is within the most active 50 miles wide zone of the country.

On March 20rd 2010 (spring equinox), just before midnight a one kilometre long fissure opened up and an eruption started in the pass Fimmvorduhals between the two glaciers on the south coast.  Earthquakes and tremours had been monitored for a long time and the authorities were well prepared for the measures to be taken in case of an eruption.  People were evacuated from the area and roads were closed until further notice.

Fissure eruptions have delivered lava to the surface in the western slopes and the pass Fimmvorduhals during Holocene.  The main crater at the top of the mountain is almost round and about 2½ km in diameter.  According to the scientists, their research in the area does not point to a lively volcanic activity, which could of course change abruptly in the future.