Report on Fagradalsfjall (Iceland) — 12 July-18 July 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 12 July-18 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, 12 July-18 July 2023. Smithsonian Institution and US Geological Survey.
63.895°N, 22.258°W; summit elev. 250 m
All times are local (unless otherwise noted)
According to the Institute of Earth Sciences lava continues to eruption from main vent at Fagradalsfjall and travel S and SW. On 14 July the advancing edge of the flow connected with the 2021 lava field in the NE part of Meradalir . The main vent was elongated and about 22 m tall on 15 July. During 13-17 July the lava flow rate was an estimated 12.7 cubic meters per second, and by 18 July the total erupted volume was about 8.4 million cubic meters. The flow advanced an average of 300-400 m per day, though the distance was highly variable. Flow thicknesses averaged 10 m, though some areas reached 20 m. At about 2330 on 18 July lava filled the main cone and occasionally spilled over onto the flanks. A breach high on the NW rim occurred at around 0251 on 19 July and lava flowed down the NW flank. Spatter was ejected beyond the crater rim. At around 0259 lava fountaining increased and lava flowed short distances E. At around 0412 sections of the NW wall of the cone collapsed, draining the crater, and sending lava flows N and W. According to Almannavarnadeild ríkislögreglustjóra and news sources the police closed the pathway to see the eruption on 13 July, then reopened the path to tourists on 17 July. Firefighters were working to control the burning vegetation set on fire by the lava.
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.