Report on Krysuvik-Trolladyngja (Iceland) — 17 February-23 February 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
17 February-23 February 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Krysuvik-Trolladyngja (Iceland). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 17 February-23 February 2021. Smithsonian Institution and US Geological Survey.
63.917°N, 22.067°W; summit elev. 360 m
All times are local (unless otherwise noted)
IMO raised the Aviation Color Code for Krýsuvík to Yellow on 24 February based on recent increased seismicity. Intense seismic activity had been detected for the previous few days and since midnight through the generation of the report at 1107 more than 500 earthquakes had been recorded. At 1005 a M 5.7 earthquake occurred 5 km W of Krýsuvík and at 1027 a M 4.2 was located in Nupshlidarhals, less than 1 km NW of Krýsuvík. The seismic unrest was unusual for the area in the context of the unrest in the Reykjanes peninsula that began in January 2020.
Geological Summary. The Krýsuvík-Trölladyngja volcanic system is described by the Catalogue of Icelandic Volcanoes as an approximately 50-km-long composite fissure swarm trending about N38°E, including a 30-km-long swarm of fissures, with no central volcano. It is one of the volcanic systems arranged en-echelon along the Reykjanes Peninsula west of Kleifarvatn lake. The Fagradalsfjall and Krýsuvík fissure swarms are considered splits or secondary swarms of the Krýsuvík–Trölladyngja volcanic system. Small shield volcanoes have produced a large portion of the erupted volume within the system. Several eruptions have taken place since the settlement of Iceland, including the eruption of a large basaltic lava flow from the Ogmundargigar crater row around the 12th century. The latest eruption, identified through tephrochronology, took place during the 14th century.