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Report on Fagradalsfjall (Iceland) — 2 June-8 June 2021


Fagradalsfjall

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
2 June-8 June 2021
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2021. Report on Fagradalsfjall (Iceland). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 June-8 June 2021. Smithsonian Institution and US Geological Survey.

Weekly Report (2 June-8 June 2021)

Fagradalsfjall

Iceland

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

All times are local (unless otherwise noted)


The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 2-8 June. The flow rate at the fifth vent, now the main lava source, was 12.4 cubic meters per second by 3 June, similar to the 11-13 cubic meters per second measured in May. Cycles of lava fountaining followed by no activity persisted at the fifth vent, though observers noted that the vent opening was getting smaller as the crater walls thickened. One observer described standing waves of lava 20 m high during a period of greater lava effusion. Lava advanced in the Nátthaga, Geldingadalur, and Merardalur valleys. The flows in Nátthaga continued to get closer to Highway 427 (Suðurstrandarvegur) to the S, covering an area with buried fiber optic communication cables. The leading edge of the flow ignited vegetation, causing small fires. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Geological Summary. Although the Fagradalsfjall fissure swarm has previously been considered a split or secondary swarm of the Krýsuvík–Trölladyngja volcanic system (https://volcano.si.edu/volcano.cfm?vn=371030), as of September 2022 Icelandic volcanologists managing the Catalogue of Icelandic Volcanoes (https://icelandicvolcanoes.is/) made the decision to identify Fagradalsfjall 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 in the next few months.

Sources: Icelandic Meteorological Office (IMO), Institute of Earth Sciences, Icelandic National Broadcasting Service (RUV), Icelandic National Broadcasting Service (RUV)