IMO reported that seismicity in the Reykjanes Peninsula remained elevated with thousands of earthquakes recorded during 10-16 March, in the western part of the Krýsuvík-Trölladyngja volcanic system in the Fagradalsfjall fissure swarm area. About 16,500 earthquakes had been detected over the week. Some of the largest events, M 4.3-5.4 recorded during 10-12 and 14-15 March, were felt as far as Hvanneyri (97 km NNE of Grindavik), Hvolsvollur (110 km ESE of Grindavik), and Saudakrokur (250 NE of Grindavik). A few, short-lived pulses of tremor were also recorded. The magma intrusion continued to move SW along a fault between Keilir and Fagradalsfjall, and was as shallow as 1 km below the surface. GPS, satellite, and seismic data indicated that the intrusion had expanded S to Nátthaga, a valley just E of Borgarfjall and S of Fagradalsfjall, and was 3-5 km long. Ground fracturing was visible in the area above the intrusion. The Aviation Color Code for Krýsuvík remained at Orange.

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.

Source: Icelandic Meteorological Office (IMO)