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Report on Fagradalsfjall (Iceland) — 19 July-25 July 2023


Fagradalsfjall

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 19 July-25 July 2023
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2023. Report on Fagradalsfjall (Iceland) (Sennert, S, ed.). Weekly Volcanic Activity Report, 19 July-25 July 2023. Smithsonian Institution and US Geological Survey.

Weekly Report (19 July-25 July 2023)

Fagradalsfjall

Iceland

63.895°N, 22.258°W; summit elev. 250 m

All times are local (unless otherwise noted)


IMO reported that lava continued to erupt from main vent at Fagradalsfjall during 19-26 July with no significant changes. Lava from the main vent, which was about 90 x 40 m, continued to advance SSW and sulfur dioxide plumes rose 1-2 km above the crater rim. Seismicity had decreased since the onset of the eruption and was concentrated at the N end of the dike and to the E of Keilir. The lava effusion rate averaged 8 cubic meters per second during 18-23 July based on calculations from the University of Iceland, the Icelandic Institute of Natural History, and the National Land Survey of Iceland. They also estimated that the total erupted volume was about 12.4 million cubic meters, and the flow field covered an area of about 1.2 square kilometers. According to a news article part of the N crater rim collapsed just before noon on 24 July, sending lava flows along a new channel, still mainly to the S but spreading more E. The hiking trails were no longer accessible 24 hours a day and were going to be closed at 1800 each day. Firefighters continued to control the burning vegetation set on fire by the lava. The Aviation Color Code remained at Orange (the third level on a four-color scale).

Geological Summary. Although the Fagradalsfjall fissure swarm has previously been considered a split or secondary swarm of the Krýsuvík–Trölladyngja volcanic system, as of September 2022 Icelandic volcanologists managing the Catalogue of Icelandic Volcanoes made the decision to identify it as a distinct separate system. The recent eruptions and related reports have been reassigned here, and other content will be prepared and adjusted as appropriate.

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