Updated 11 November 2025
Key Points
Deformation Measurements
Recent deformation measurements reveal a continuing uplift and magma accumulation beneath Svartsengi, though the inflow rate is showing a gradual decline. Historical patterns from previous eruptions in the Sundhnúkur crater row suggest that the chances of a new magma intrusion, followed by an eruption, increase when a substantial amount of magma has accumulated—similar to what was observed before the last eruption. Since March 2024, the volume of magma expelled from Svartsengi during eruptions has fluctuated between 12 and 31 million cubic meters. Currently, it is estimated that around 15 million cubic meters of magma have built up beneath Svartsengi since the last eruption in July, leaving considerable uncertainty regarding the timing of the next event.
As the magma inflow decreases, the projected timeframe for when an eruption could occur has extended. Early October marked the moment the lower volume threshold of 11 million cubic meters was crossed, with projections indicating that the upper threshold of 23 million cubic meters—based on average figures from the last five eruptions—may be reached by early February if the current inflow rates persist.
The accompanying graph illustrates magma accumulation at a depth of 4 km beneath Svartsengi, with black dots marking daily measurements from July 2025 to the present. The shaded area forecasts magma accumulation at a consistent inflow rate, while the red dashed line suggests a likely downward trend in inflow. The critical volume thresholds of 11 and 23 million cubic meters represent estimated bounds for potential magma intrusion and eruption.
Seismic Activity
Seismic activity near Grindavík and along the Sundhnúkur crater row remains relatively quiet; on most days, only a handful of microearthquakes—typically around magnitude M1—are recorded.
Activity near Krýsuvík
Deformation measurements indicate that the subsidence ongoing in Krýsuvík since summer has drastically slowed, with only minimal deformation currently observed. While earthquakes continue to register a few times daily, their frequency has dropped significantly—from 250 to now between 100 and 150 per week. This sustained decline marks a notable change in the seismic pattern since summer.
Hazard Assessment
The hazard map has been revised but remains unchanged until November 25. The Icelandic Meteorological Office is closely tracking developments and will provide updates should the situation change.
Updated 28 October 2025
Around 14 Million Cubic Meters of Magma Accumulated Beneath Svartsengi Since Last Eruption
Key Points
- Uplift and magma accumulation beneath Svartsengi persist.
- Magma outflow during past intrusion events has ranged from 12 to 31 million cubic meters.
- Substantial uncertainty lingers regarding the timing of the next event.
- The hazard assessment remains unchanged and valid until November 11.
- Subsidence continues in the Krýsuvík area, although at a reduced pace in recent weeks.
Deformation
Approximately 14 million cubic meters of magma have accumulated beneath Svartsengi since the last eruption. Drawing from historical data on the Sundhnúkur crater row, the likelihood of a new phase of magma intrusion and eruption significantly increases when the magma volume recharged equals what was expelled during previous events. Notably, magma recharged since March 2024 has varied from 12 to 31 million cubic meters, thus emphasizing the uncertainty surrounding the precise timing of any forthcoming eruption.
Earthquake Activity
Seismic readings around Grindavík and the Sundhnúkur crater row continue to indicate low activity, with minor earthquakes typically measuring just above magnitude 1.0. Recent events included a brief swarm of small quakes on October 11, during which over 20 quakes were detected; however, this has mostly settled to about five daily tremors since then.
Activity near Krýsuvík
Earthquake occurrence near Krýsuvík remains ongoing, with several minor quakes recorded daily. Notably, on October 22, two quakes of magnitude 3.1 and 3.6 were detected west of Kleifarvatn, contributing to a weekly tally exceeding 120 quakes. Subsidence—first noted this summer—continues, measuring about 55 mm at the Móhálsadalur GPS station since early June, although the rate of decline has slowed in more recent weeks.
Hazard Assessment
The hazard assessment provided by the Icelandic Meteorological Office has been updated and remains unchanged until November 11, pending any shifts in activity.
Continuous Monitoring
The Icelandic Meteorological Office conducts round-the-clock monitoring of all natural hazards within Iceland, employing real-time surveillance of seismic activity, ground deformation, and gas emissions. Alerts are issued as warranted, while updates regarding volcanic activity are regularly disseminated through the news platform vedur.is to ensure that stakeholders and response agencies are informed daily. Weekly summaries of the volcanic systems’ status are shared with relevant partners, providing a comprehensive overview of volcanic risk management.
For a deeper dive into Iceland’s volcanic systems, visit the Icelandic Volcano Web Portal: islenskeldfjoll.is