The Icelandic Meteorological Office (IMO) reported that a fissure within the Reykjanes volcanic system that began erupting on 16 July in an area NE of Stóra Skógfell, along the Sundhnúkur crater row, continued to erupt during 23-29 July. Measurements of the flow field taken on 23 July indicated that the total volume of new lava in the Sundhnúkur area was estimated to be 26.8 million cubic meters and covered an estimated 3.3 square kilometers. One crater continued to produce lava flows and periodic spatter; activity at the crater declined during the mornings of 23 and 24 July and then remained stable during the rest of the week. A small vent opened on the W flank of the crater’s cone on 28 July but was inactive by 29 July. During 28-29 July a new crater formed inside the main crater and became the center of the activity. Lava flowed E and SE. The flow thickened with only minor changes to the flow margins; a small breakout at the SE part of the flow traveled a short distance S. Sulfur dioxide emissions significantly decreased during 23-24 July, though on 24 July volcanic smog (vog) was widely reported, including in Ísafjörður (about 240 km N) and Strandir (about 200 km NNE). A small amount of vog was detected in some areas overnight during 24-25 July. Gas emissions during 28-29 July drifted over populated areas in SW Iceland.

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)