The Grímsvötn Volcano is situated underneath Vatnajökull, Europe’s largest glacier, 220 km ENE of Reykjavík. Eruptions at Grímsvötn are frequent; usually they occur at an interval of a few years. Latest outburst was in 2004. Most of these eruptions last a few days and are small in volume.
The Grímsvötn volcano is a caldera or depression in the earth’s crust. There is great geothermal activity within the caldera. The geothermal power melts the glacial ice and the meltwater collects in the caldera. Periodically the meltwater forges a path underneath the glacier and flows to the south towards and over the uninhabited Skeiðarársandur in what is termed a glacial outburst flood.
This year’s eruption, however, is much larger than that at Eyjafjallajökull last year. Currently the volcano is ejecting material equivalent to ten thousand cars per second!
Thanks Joey (from Sweden)