IMO reported that the eruption that began on 29 May near Sundhnúk, NE of Sýlingarfell, within the Reykanes volcanic system, continued through 11 June. The lava field had an estimated area of 8.6 square kilometers and the erupted volume was about 36 million cubic meters based on a 3 June drone survey. The estimated flow rate during 29 May-3 June was 30 cubic meters per second. Only one crater was active by the morning of 4 June, and the flow rate had likely decreased. Lava flows advanced NW towards Sýlingarfell and S towards Hagafell on 5 June. On 7 June flows continued to advance N towards Sýlingarfell, causing the flow field in that area to thicken, and continued on expand N and W. Deformation data indicated that deflation had ceased. A small collapse of the crater wall was visible according to a news source. The rate of lava advancement increased during 7-8 June in an area N of Sýlingarfell, towards Grindavíkurvegur. By 1030 on 8 June lava had crossed Grindavík road just to the N of where work was being done to close a gap in an earthen barrier. Lava also moved along the barrier and in some areas flowed over the top. The flows had slowed by noon, reaching 800 m from hot water pipelines. Inflation began to be detected sometime during 8-9 June though the rate of uplift had not been determined. The eruption continued during 9-11 June. Lava continued to accumulate in a lava pond just SE of Sýlingarfell. Notable sulfur dioxide pollution from the eruption was measured in many parts of Reykjavík and in the W part of South Iceland. Vog was noticeable in the W part of the country during the morning of 11 June.

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.

Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV)