Report on Fagradalsfjall (Iceland) — 7 April-13 April 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
7 April-13 April 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, 7 April-13 April 2021. Smithsonian Institution and US Geological Survey.
63.895°N, 22.258°W; summit elev. 250 m
All times are local (unless otherwise noted)
IMO reported that the fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 7-13 April. Lava from the third fissure flowed S into Geldingadalur and NE towards the Meradalir valley site. Flows from the three fissures connected into one flow field on 7 April. Another new fissure opened at around 0300 on 10 April, halfway between two existing fissures, and all four fissures were simultaneously active. Lava flowed towards Geldingadalur. Gas-rich emission plumes were visible in webcam images rising 1.1-1.3 km (3,600-4,300 ft) a.s.l. At least two new vents opened on 13 April based on webcam views. On 14 April IMO noted that lava was flowing from at least eight vents and unverified reports form the morning suggested two additional vents had opened. Sulfur dioxide gas flux was 29 kilograms per second, comparable to measurements collected during the previous few weeks.
IMO warned visitors that new fissures could open without adequate visible warning, especially in an area just S of Keilir, by Litla-Hrút, where seismicity was concentrated. They also warned of increased gas emissions hazards. 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 (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.