On 7 May IMO reported that the cone just E of Sundhnúk and along the fissure within the Reykanes volcanic system continued to erupt lava, though activity had decreased during the previous few days. Lava flowed short distances from the vent; no significant changes were observed at the S part of the flow field near the earthen barriers at Grindavík. Inflation from magma accumulation beneath Svartsengi was first detected at the beginning of April and the rate of inflation was unchanged for the past few weeks based on modeling of GPS and satellite data. Seismicity increased steadily during the past week. Most of the earthquakes were below M 1 and located N of the vent between Sundhnúk and Stóra Skógfell, S of Mt. Thorbjorn in a valley near Grindavík, and in an area between the vent and Grindavík.

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)