Volcanic Activity Report on Fagradalsfjall (Iceland) — 31 March-6 April 2021

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 31 March-6 April 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, 31 March-6 April 2021. Smithsonian Institution and US Geological Survey. https://volcano.si.edu/showreport.cfm?gvpvar=GVP.WVAR20210331-371032

Fagradalsfjall

Iceland

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 31 March-6 April. Video and visitor photographs showed spattering and lava fountaining from the two cones, and lava flows from both cones moved W and S within the Geldingadalur valley. A new fissure, 100-200 m long, opened about 700 m NE of the Geldingadalur cones around noon on 5 April. During a helicopter overflight, scientists observed a gas plume rising from the new fissure and a fast-moving lava flow descending into the Meradalir valley to the SE. On 6 April lava from the second fissure was advancing at a rate of 7 cubic meters per second; lava-flow rates at the Geldingadalir site averaged 5.5 cubic meters per second. Around midnight during 6-7 April a third fissure opened in between the first two; all three were oriented NE-SW. Earlier on 6 April field teams had observed a landslide in same area. Lava from the third fissure mostly flowed SW into Geldingadalur. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO), Icelandic Coast Guard

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.