The Icelandic Meteorological Office (IMO) reported that the eruption that began on 20 November at the Sundhnúkur crater row in a location between Stóra-Skógfell and Sýlingarfell, within the Reykjanes volcanic system, likely ended on 8 December. Activity at the main cone had slowly decreased over the previous days along with tremor levels. The comparison of InSAR images acquired on 30 November and 4 December, as well as deformation data from several GPS stations, indicated that inflation had resumed at Svartsengi from the accumulation of magma beneath the region. Air pollution from volcanic gases persisted at least through 6 December even though activity at the crater was declining. Incandescence at the cone was last observed in webcam images at around 0700 on 8 December and no activity was observed during a drone overflight at 1400 on 9 December. The eruption lasted for 18 days. On 9 December the Aviation Color Code was lowered to Yellow (the second lowest level on a four-color scale).

Geological Summary. The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula.

Source: Icelandic Meteorological Office (IMO)