The Icelandic Met Office has issued a fresh Reykjanes Peninsula update, and the broad picture has not changed: magma continues to accumulate beneath Svartsengi, uplift is slow but persistent, and seismicity remains low. What has changed is the modelled volume. IMO now estimates that about 29.1 million cubic metres of magma has accumulated beneath Svartsengi since the start of the last eruption in July 2025.

The latest official picture

Svartsengi continues to inflate slowly, earthquake activity remains subdued, and IMO's most likely future scenario is still another magma movement from Svartsengi into the Sundhnúkur crater row — a process that could lead to a new eruption.

29.1 million cubic metres beneath Svartsengi

IMO's latest model calculation covers the period from 17 July 2025 to 16 August 2026. It gives a central estimate of around 29.1 million m³ of accumulated magma beneath Svartsengi. The stated uncertainty range is 28.3 to 29.9 million m³.

The estimate is based on GNSS measurements and InSAR data. IMO says the land around Svartsengi continues to rise slowly but steadily, indicating that magma is still entering the system even though the deformation rate is not rapid.

29.1M m³Central model estimate
28.3M m³Lower end of IMO's uncertainty range
29.9M m³Upper end of IMO's uncertainty range
Svartsengi — latest modelled magma volume IMO estimate for 17 July 2025 to 16 August 2026
MODELLED VOLUME (MILLION m³) 29.1M m³ central estimate 28.3 29.9 95% uncertainty range stated by IMO Slow, steady land rise at Svartsengi continues
This diagram reproduces only the numerical estimate and uncertainty range stated in IMO's 18 August 2026 update. It is not a reconstruction of the original IMO graph.

Seismic activity remains low

Despite the continued build-up beneath Svartsengi, IMO reports that earthquake activity along the Sundhnúkur crater row and in the area around Grindavík remains low.

That matters because the current situation is one of continued pressure accumulation without a corresponding surge in seismicity. IMO does not interpret the low earthquake rate as evidence that the magmatic system has stopped recharging; the deformation data continue to show accumulation beneath Svartsengi.

The most likely scenario is unchanged

IMO's assessment of what may happen next is also unchanged. As magma continues to accumulate and pressure increases, the agency considers the most likely scenario to be another movement of magma from Svartsengi into the Sundhnúkur crater row. Such an intrusion could lead to an eruption.

IMO's most likely scenario A sequence described by the Icelandic Met Office — not a prediction of timing
SVARTSENGI Magma continues to accumulate PRESSURE BUILDS Slow, steady uplift continues SUNDHNÚKUR CRATER ROW Possible magma intrusion from Svartsengi Could lead to an eruption IMO states this is the most likely scenario as pressure continues to build. It does not mean an eruption has begun or that a start time can be predicted.
The sequence above paraphrases IMO's stated scenario. It deliberately separates the possible intrusion from a possible eruption because the official update says an intrusion could lead to an eruption, not that eruption is guaranteed.

Warning time could still be short

IMO again emphasises that if magma begins moving from Svartsengi towards Sundhnúkur, the warning period may be limited. The agency says previous eruptions in this cycle have had notice periods ranging from roughly 20 minutes to more than four hours.

What that figure does — and does not — mean

The 20-minute to four-hour range describes previous warning periods. It is not a forecast for the next event. IMO's latest update does not give a date or time for a new intrusion or eruption.

Current hazard assessment

IMO says the Reykjanes hazard assessment is unchanged and remains valid until 30 September 2026. The official assessment map below provides the geographic context for the hazards currently considered across the peninsula, including the Grindavík, Svartsengi, Vogar and Reykjanesvirkjun assessment areas.

Official Reykjanes hazard assessment map Icelandic Met Office — current assessment referenced in the 18 August 2026 update
Official Icelandic Met Office hazard assessment map for the Reykjanes Peninsula, showing hazard zones around Grindavík, Svartsengi, Sundhnúkur and surrounding areas.
Official hazard assessment map from the Icelandic Met Office (Veðurstofa Íslands). The 18 August update states that the risk assessment remains unchanged and is valid until 30 September 2026. The map is reproduced here for geographic context; readers should use IMO's current assessment for official safety information.

How to read this map

The coloured areas represent IMO's assessed hazard levels and monitoring areas. They should not be interpreted as a forecast of where the next eruption will begin. The 18 August update continues to identify magma movement from Svartsengi into the Sundhnúkur crater row as the most likely scenario, while stating that the overall risk assessment itself is unchanged.

For residents and anyone following the Reykjanes activity closely, the key point is that the system is still recharging. Uplift is slow, seismicity is low, and there is no official declaration that a new eruption is underway — but magma accumulation beneath Svartsengi continues and the preferred scenario remains another intrusion towards Sundhnúkur.

What to watch next

The signals that matter most are any change away from the current slow pattern: a significant increase in earthquake activity, changes in deformation, or evidence that magma has started leaving the Svartsengi storage area. IMO's monitoring network is designed to detect those changes, but the agency's reminder about potentially short notice remains important.