Report on Reykjanes (Iceland) — 10 June-16 June 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 June-16 June 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Reykjanes (Iceland). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 June-16 June 2020. Smithsonian Institution and US Geological Survey.
63.85°N, 22.566°W; summit elev. 140 m
All times are local (unless otherwise noted)
IMO reported that a third injection of magma since the beginning of the year was occurring beneath the Reykjanes peninsula. Data suggested that the current inflationary period began in mid-May, though earthquake activity did not increase until around 30 May. During 30 May-15 June the seismic network recorded more than 2,000 events, with the largest, an M 3.4, recorded on 13 June. The intrusion was located about 1 km W of Thorbjorn at a depth of 3-4 km, and had an estimated volume of about 1.2 million cubic meters. This third intrusion was similar to the previous two intrusions, characterized as a sill that was a few hundred meters wide and about 6 km long. In total about 12 cm of uplift has been recorded since January. The Svartsengi geothermal plant noted no chemical changes in the geothermal system, though measurements showed increased fluid flow in the rocks within the system, along with the opening of old cracks and the formation of new ones.
Geologic Background. 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.