Askja volcano (Iceland): significant ground deformation since August

The image depicts the near-vertical deformation in mm for the period 1-21 August. The InSAR image is obtained from two passages of Sentinel-1 satellite. The red color indicates uplift and the blue corresponds to subsidence (see the scale). The area experiencing the highest inflation is north-west Öskjuvatn. The black triangle indicates the location of the closest GPS station Ólafsgíga (OLAC) (image: IMO)

The Icelandic Meteorological Office (IMO) reported that GPS observations and ground deformation maps from Sentinel-1 satellite data detected that the volcano began to inflate at the beginning of August 2021. The uplift signal is centered on the western edge of Öskjuvatn, close to Ólafsgígar, and corresponds to ~5 cm/month of vertical motion. Geodetic modeling 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 a new batch of magma as a larger gas bubble rose towards the surface inside the magma-filled conduit.

Source: Icelandic Meteorological Office volcano activity update 8 September 2021