IMO reported that the eruption that began on 29 May near Sundhnúk, NE of Sýlingarfell within the Reykanes volcanic system, continued through mid-June. The flow field was an estimated 9.2 square kilometers on 10 June, and the erupted volume was an estimated 41 million cubic meters. The eruption continued during 11-18 June, with lava from one active crater that traveled mostly N alongside Sýlingarfell, fed a lava lake, and then flowed onto the N part of the flow field causing it to thicken. Lava also accumulated S of the crater. Sulfur dioxide pollution from the eruption was notable during 12-13 June, especially near Blue Lagoon and Hafnir, and was expected to continue to impact areas downwind. As of 13 June, the lava flow at Grindavík road advanced very slowly and continued to thicken. Around noon on 17 June a small opening appeared on the W crater rim and fed a lava flow that traveled a short distance W. Drone data collected on 10 June indicated that this is the largest of the five eruptive episodes that have occurred in the area since December 2023, both in terms of area and volume.

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)