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Report on Fagradalsfjall (Iceland) — 24 March-30 March 2021


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 24 March-30 March 2021
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2021. Report on Fagradalsfjall (Iceland) (Sennert, S, ed.). Weekly Volcanic Activity Report, 24 March-30 March 2021. Smithsonian Institution and US Geological Survey.

Weekly Report (24 March-30 March 2021)



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

All times are local (unless otherwise noted)

IMO reported that the small eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula continued during 24-30 March. Video and visitor photographs showed that continuous spattering and lava fountaining resulted in the formation of a second large cone adjacent to the main cone. Lava flows from both cones moved W and S within Geldingadalur valley. On 25 and 29 March the extrusion rate from the cone was an estimated 5.8 and 5.3 cubic meters per second, respectively, based on the latest Pléiades image acquisition (LMI).

A gas plume on 25 and 29 March rose to 1 km (3,300 ft) a.s.l; no ash or tephra was produced. Minor seismicity continued around the Fagradalsfjall area. Video data showed that on the morning of 28 March the N part of the largest cone along the fissure collapsed. Sulfur dioxide flux was 18-19 kg/s and drifted predominantly S. The IMO periodically issued warnings about weather conditions that would cause high concentrations of volcanic gases to settle near the eruption site, causing hazardous conditions for visitors. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

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)