Strong earthquake swarm in Bárðarbunga. Largest earthquake magnitude 5.1
Approximately 130 earthquakes recorded since this morning. Most significant swarm since the 2014 Holuhraun eruption
- The largest earthquake was of magnitude 5.1 at 8:05, and 17 earthquakes measured magnitude 3 or higher
- Seismic activity in Bárðarbunga has increased in recent months
- The swarm was highly intense until 9:00 this morning, after which activity began to decrease
- The aviation color code for Bárðarbunga has been raised to yellow
- The volcano is unusually large, with several possible scenarios for future developments
A strong earthquake swarm began shortly after 6:00 UTC today in the northwestern part of the Bárðarbunga caldera. Approximately 130 earthquakes have been recorded since the swarm began, with the largest reaching magnitude 5.1 at 8:05 UTC.
Additionally, 17 other earthquakes with a magnitude of 3 or higher were detected, including at least two measuring magnitude 4 or above. These estimates may change as analysis of the events is ongoing.
Earthquake activity was most intense until around 9:00 UTC, after which it began to decrease, though earthquakes are still being recorded in the area. It is too early to determine whether the swarm is subsiding.
A composite image from the Icelandic Meteorological Office's earthquake monitoring system. The map in the upper left corner shows the locations of the earthquakes, with the black circle indicating the Bárðarbunga caldera outline. The upper-right graph displays earthquake magnitudes, where darker bars represent reviewed events, and lighter bars represent unreviewed data. The lower-left graph shows the cumulative number of earthquakes, while the lower-right graph indicates the hourly earthquake count.
Increased inflation and magma accumulation since 2015
This is the most significant activity in Bárðarbunga since the 2014-2015 eruption in Holuhraun. The observed seismicity is consistent with increased pressure caused by magma accumulation, which has been ongoing since the last eruption in 2015. Earthquake activity has been increasing gradually in Bárðarbunga over recent months. Notably, four earthquakes measuring magnitude 5 or higher were detected in 2024. Additionally, geodetic deformation data suggests an increased rate of inflation at the volcano.
Multiple scenarios considered
IMO will continue to monitor the activity closely, but it is difficult to predict how it will develop at this point. Bárðarbunga is unique in that it is an unusually large volcanic system, partly covered by a glacier, and several scenarios are possible.
Extensive research, along with hazard assessments and contingency planning, was conducted during the 2014–2015 eruption, which will prove valuable should further volcanic activity occur.
Magma intrusions, or dyke formations, from the caldera could lead to eruptions outside the caldera, as seen in the 2014-2015 Holuhraun eruption and the Gjálp eruption in 1996. Alternatively, an eruption could even occur within the caldera itself. Should an eruption take place beneath the glacier, it may trigger explosive ash emissions and glacial outburst floods (jökulhlaup). However, if an eruption occurs outside the glacier, it will likely result in a lava-producing event.
As a precaution, the aviation colour-code for Bárðarbunga has been raised to Yellow, indicating heightened activity above normal background levels.
For more information about the Bárðarbunga volcanic system, visit the Catalogue of Icelandic Volcanoes
