Uncertainty Phase Declared As Eruption Could Follow Glacial Flood At Grímsvötn

The Department of Civil Protection and Emergency Management has declared an uncertainty phase around Grimsvötn volcano, as an ongoing jökulhlaup (a glacial outburst flood) could herald an eruption. Grimsvötn is a volcano located under the Vatnajökull glacier, in the southeast of Iceland.

In addition to the glacial flooding, Grímsvötn was shook by a 4.3 magnitude earthquake around 07:00 Thursday morning. That is the largest quake recorded in the area since measurement began in 1991. Geologist Magnús Tumi Guðmundsson told the national broadcaster Grímsvötn is currently in a period of heightened activity, which could last 60 to 80 years.

The glacial flooding has been ongoing for a couple of days and is considered small. It is not expected to cause any damage to roads of settlements. Magnús Tumi explains that “when there are glacial floods, the water level in Grímsvötn drops, and then the pressure on top of the magma chamber that is under there decreases.”

The Icelandic Meteorological Office has a summary of the various types of glacial outburst floods and what causes them.

An eruption followed a glacial flood at Grímsvötn most recently in 2004. Prior to the 2004, eruptions of the volcano followed glacial floods in 1934 and 1922. Glacial floods have also occurred at Grímsvötn without an eruption following, in 2021 and 2022, for example.