The eruption seen from the Coast Guard's surveillance flight with Grindavík in the foreground. The picture was taken at 00:15, March 17. (Photo: Public Safety/Björn Oddsson)
Updated Hazard Assessment
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Iceland Met Office
Updated 20. March at 13:45 UTC
The eruptive activity appears to be relatively stable and eruptive vents remain in the same locations as yesterday. Lava flows from the craters towards the south, on top of lava which flowed in the first days of the eruption. Little or no movement has been detected on the lava flow fronts near the South Coast Road and Svartsengi. Seismic activity since the eruption began on Saturday night has been minor.
The weather forecast is increasing south-easterly winds today, 13-20 m/s in the afternoon, but subsides in the evenings. Gas pollution is thus dispersed to the northwest and could be detected in Reykjanesbær and nearby areas. Gas distribution forecast can be found here. On 17 March, SO2 gas emission from the eruption was measured up to 50 kg/s, but preliminary results from new measurements indicate that the emission of gas has decreased considerably since then.
An InSAR image published yesterday showed clear signs of land inflation in Svartsengi from 17 to 18 March. GPS data from 18 March suggest that the inflation rate is possibly decreasing. This could be due to magma now flowing towards the surface in the Sundhnúkur crater row and therefore not accumulating beneath Svartsengi. The development of the eruption and deformation signals over the next few days will reveal whether an equilibrium will be reached between the magma inflow beneath Svartsengi and the lava flow on the surface in the Sundhnúkur crater row.
This morning, experts from the National Land Survey of Iceland and the Institute of Natural History conducted aerial photography flights over the eruption site. From these images it is possible to estimate the size of the lava field and the average lava flow from the eruption. Their estimates will be published as soon as the data have been processed.
Figure caption: Overview of the eruption site taken on a flight this morning. It shows all the active volcanic vents and flava flows from them to the south. In the background to the left is Grindavík and to the right is Svartsengi. (Image: Birgir V. Óskarsson – Institute of Natural History).
Updated Hazard Map
The Icelandic Meteorological Office has updated its hazard assessment in light of the latest data. The new hazard assessment takes effect today, Wednesday, March 20, and is valid until March 22, unless the situation changes. Zone 3 (the Sundhnúkur crater row), where the eruption is still ongoing, remains unchanged, and the danger is considered very high. The danger in zone 1 (Svartsengi) is now considered considerable, whereas it was previously considered high. The danger in zone 4 (Grindavík) remains high as the risk due to sinkholes, fault movements and lava flow is considered high. In zone 3 (the Sundhnúkur crater row), the risk due to gas pollution is considered very high, but in all other areas, the risk of gas pollution is now considered considerable, whereas it was previously high. This change is due to lower gas emissions from the eruption than at the beginning. The danger due to gas pollution and ash is also assessed based on the weather and dispersion forecast for the next few days, which affects their spread.
(Click on the map to see it larger)
Updated 19. March at 17:30 UTC
- The eruption continues and has been ongoing since 16 March at 20:23 UTC.
- Volcanic tremor is detected and has remained relatively stable for the past two days which indicates that the eruption‘s vigour has not decreased.
- Inflation continues in Svartsengi, suggesting that magma is still ascending from depth into the magma reservoir beneath Svartsengi as well as flowing towards the eruptive site.
- The hazard assessment map updated yesterday (18 March) is unchanged.
The eruption continues and has now lasted for over two and a half days, which is longer than the previous three eruptions that have occurred in the area since December 2023. The eruptive activity is in the same places as yesterday afternoon, on the southern part of the volcanic fissure. Crater rims continue to build up and lava fountaining is still considerable. The lava flow front, which was approximately 300 m from the South Coast Road yesterday, does not appear to have moved forward. Lava flow from the craters remains mostly to the south, with active lava flow fronts on top of the lava that flowed at the beginning of the eruption.
Seismic activity has been negligible at the dike area since the eruption started, but volcanic tremor is detected and has remained relatively stable over the past two days, an indication that the eruption's vigor has not decreased.
When magma propagated from Svartsengi towards the Sundhnúkur crater row on the evening of 16 March, land subsidence was detected in Svartsengi, as when previous magma dike formed. GPS data and satellite images received after the magma propagation show that surface inflation continues in Svartsengi, suggesting that magma is still ascending from depth into the magma reservoir beneath Svartsengi as well as feeding the eruption.
It should be noted that relatively few data points have still been obtained in the short time since the eruption began and that the data is always subject to uncertainty. Deformation data, which will be available in the next few days, will allow experts to further estimate using model calculations the amount of magma flowing in under Svartsengi.
InSAR image showing measured inflation (red areas) between 17 and 18 March after the eruption began. The image is based on data from the ICEYE satellite. (Click map to enlarge)
According to measurements carried out last night, the outflow of gas from the eruption has decreased compared to what it was at the beginning of the eruption. However, it is still likely that gas pollution will be detected, and the weather forecast indicates increasing south-westerly winds, around 13-20 m/s at the eruption site today, but winds will decrease this evening. Gas pollution is thus directed to the north-east. See gas distribution forecast here.
The hazard assessment map updated yesterday remains unchanged until 15:00 tomorrow 20 March, barring any changes to the situation.
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