Icelandic eruption
Grimsvotn volcano in SE Iceland erupted on Saturday evening (21 May) after a period of inflation and a brief earthquake swarm. The initial eruption column reached about 20km in height, dropping to 10-15km subsequently, with a high magma discharge rate. The eruption is considerably larger in intensity than last year’s eruption of Eyjafjallajokull, which caused air traffic disruption over Europe. Icelandic air space is closed and effects on Europe will depend on weather conditions in the coming days and the duration and continuing intensity of the eruption. Grimsvotn is the most active volcano in Iceland and erupts approximately every 10 years; it last erupted in 2004. Eruptions typically last from a few days to a couple of weeks. Grimsvotn lies under the Vatnajokull ice cap and so the eruption intensity is increased by interaction of meltwater with the magma, causing more explosivity and so finer ash. Thick ash is accumulating around the eruption site in SE Iceland, and although this is reported as coarser than the Eyjafjallajokull ash, the eruption column will also contain fine ash that will be carried in the eruption plume. Flooding caused by outbursts of meltwater is a common hazard in the local area to the south of Vatnajokull.
For more information and to follow the course of the eruption see http://www.earthice.hi.is/
For technical data see http://hraun.vedur.is/