IMO reported that the cone just E of Sundhnúk and along the fissure within the Reykanes volcanic system continued to erupt lava during 15-23 April. Gas emissions continued to drift downwind and residents were advised to monitor air quality. Lava flowed a short distance from the crater mostly S and the flows thickened near the crater. Lava tubes in an area about 1 km SE transported lava to an active flow field N of Hagafell; webcam images showed inflation of the part of the flow field located along the barriers E of Grindavík during 18-23 April. Inflation from magma accumulation beneath Svartsengi was first detected at the beginning of April and continued at a steady rate based on modeling of GPS and satellite data.

The average effusion rate was 3-4 cubic meters per second during 1-15 April. Results from a 15 April overflight where scientists acquired images for mapping showed that the lava-flow field was an estimated 6.15 square kilometers with an approximate volume of 33.2 (± 0.8) million cubic meters.

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)