The land by Askja volcano in central Iceland is rising at a rate of 5cm per month, according to the Iceland Meteorological Office. This is likely due to new magma flowing towards the surface. Such an event can end in a volcanic eruption but it’s also possible that the magma cools and hardens without ever reaching the surface. There are currently no indications that an eruption is imminent.
According to the Iceland Meteorological Office, GPS observations and ground deformation maps derived from Sentinel-1 satellite data reveal that Askja volcano began inflating at the beginning of August 2021. Askja is located in Iceland’s central highland, north of Vatnajökull glacier. The uplift signal is centred on the western edge of Öskjuvatn, close to Ólafsgígar, and corresponds to ~5 cm/month of vertical motion. Geodetic modelling (performed using both GPS and satellite data) indicates that the source of this inflation is located at a depth of approximately 3 km and corresponds to a volume change of approximately 0.001 km³/month.
The cause of such inflation is uncertain, but most likely it is due to the inflow of new magma. Askja volcano is seismically active and earthquakes are regularly detected in the area but there is no change in seismic patterns indicating increased volcanic activity according to Sigþrúður Ármannsdóttir with the Icelandic Met Office.
The last eruption at Askja was in 1961 and lasted for 5-6 weeks. In 1970-1972, regular geodetic measurements showed a period of uplift, but when measurements resumed in 1983 the land had begun sinking again. Since then, continued subsidence of a rate of 1 cm/year was detected until this current inflation phase started.
The Met Office notes that active volcanoes in Iceland are often characterized by periods of inactivity, lasting years to decades, with intervals of enhanced seismicity, geothermal activity, and inflation. In most cases, magmatic intrusions do not culminate into an eruption. The ongoing eruption in Reykjanes began about a year after land started to rise in the area. At this stage, there is no immediate danger to travellers in the area. It is very difficult to anticipate how the situation will evolve but the Met Office will continue to monitor the situation.