This isn't a bulletin about what's happening right now beneath Svartsengi. It's something arguably more significant — a systematic, science-based map of where lava hazard on the Reykjanes Peninsula is concentrated over the long term, and what that means for the half a million people who live there.
What This Assessment Actually Is
Published on 21 April 2026, this is the first part of the IMO's long-term lava hazard assessment for the Reykjanes Peninsula — a project commissioned by Iceland's Ministry for the Environment, Energy and Climate in early 2024, in direct response to the surge of volcanic activity that began the previous year. The full project runs until 2027 and will eventually cover lava flow, fissure hazard, earthquake risk, tephra fall, gas pollution and groundwater contamination.
What today's report tackles is the foundational question: based on where eruptions have happened before, and how lava has behaved when it reached the surface, which parts of the peninsula face the greatest long-term lava hazard?
Important distinction: This long-term assessment does not replace the IMO's short-term hazard bulletins for the Svartsengi–Sundhnúkur system. Those are based on real-time monitoring data and remain the operative guidance for imminent eruption risk. This report operates on a geological timescale, not a days-to-weeks one.
Where Eruptions Are Most Likely to Begin
The IMO modelled eruption site probability across all seven volcanic systems using a combination of eruption history, geology, fissure locations, young hyaloclastite ridges, geothermal areas and plate boundaries. Areas with a track record of repeated eruptions were weighted most heavily.
The results confirm what geologists have long understood, but now with statistical rigour: the greatest eruption site probability is concentrated along the central cores of each volcanic system and where those systems cross the plate boundary. Grindavík is the only urban settlement sitting close to a zone of very high eruption probability. All four of Iceland's Reykjanes power stations — Reykjanes, Svartsengi, Hellisheiði and Nesjavellir — lie within zones rated as having considerable to very high eruption site probability.
All four power stations serving the Reykjanes Peninsula are located within areas rated considerable to very high for eruption site probability. This is not a new discovery, but it is now formally quantified.
Where Lava Could Flow — and What's at Risk
Eruption site probability is only half the picture. The report also models lava flow behaviour across four scenarios, using real observational data from the 2021–2024 eruptions at Fagradalsfjall and Svartsengi as the basis for calibration. Each scenario simulates how lava moves across the landscape given different eruption sizes and flow rates.
The headline findings from the highest-impact scenario — described as medium-flow, average-sized eruptions — are sobering but not surprising:
- Grindavík sits in a zone of very high lava flow probability and very high eruption site probability — the only settlement to face both simultaneously
- Hveragerði falls within the top 10% hazard zone for lava flow, though its eruption site probability is lower — risk comes from flow paths, not proximity to a vent
- Part of Hafnarfjörður lies approximately one kilometre from the edge of the highest-hazard zone for lava flow
- Four power stations and two water sources sit within the top 10% highest-impact areas across the peninsula
- Three municipalities on the peninsula include areas rated considerable to very high for lava flow probability
What It Means for Greater Reykjavik
The capital region fares considerably better. Even under the widest-impact scenario modelled, the majority of greater Reykjavik sits in areas rated very low or low for lava flow probability. The models do, however, reproduce known historical lava flow paths toward the capital from the Krýsuvík and Brennisteinsfjöll volcanic systems — a reminder that the risk, while low, is not zero on geological timescales.
The IMO is clear that this assessment is not a prediction of what the next eruption will do. It is a probability map — a tool for planners, infrastructure operators and emergency services to understand where long-term exposure is greatest. As volcanologist Bergrún Arna Óladóttir put it in the report: the scenarios shown are possibilities, not forecasts. They do not say where or when the next eruption will occur, or whether lava will reach any given area in the coming years.
A new interactive map viewer has launched alongside the report at eldfjallava.vedur.is, allowing planners and the public to explore hazard zones by scenario. GIS data layers are available for download. Full reports can be accessed via eldfjallava.is.
The Bigger Picture: A Project Unlike Any Other
The IMO itself describes this as one of the most comprehensive volcanic hazard assessments ever undertaken anywhere in the world. Producing a unified, multi-hazard assessment covering seven volcanic systems, sixteen municipalities and a population of over half a million people — while simultaneously responding to six eruptions totalling more than 200 days of active lava output — is, by any measure, an extraordinary undertaking.
Around twenty IMO specialists are involved. The same scientists producing these reports were also on monitoring duty during every eruption on the Sundhnúkur crater row. More reports are due this year covering fissure hazard, additional lava hazard zones for the Suðurnes and southern Árnes regions, and earthquake hazard. Tephra fall, gas pollution and groundwater reports follow in 2027.
The report's findings will feed directly into planning regulations, infrastructure decisions and the ongoing work of the Grindavík Committee, which is developing a framework for the town's long-term future. What constitutes "acceptable risk" for a settlement like Grindavík — a question the hazard maps illuminate but do not answer — is now the central political and social conversation Iceland must have.