Flows pose danger to infrastructure in Grindavik, and hundreds of people are evacuated from nearby Blue Lagoon

Emergency teams worked through the night to bolster defensive barriers around the evacuated fishing town of Grindavik as lava from the fourth volcanic eruption on Iceland’s Reykjanes peninsula since December flowed towards it.

After weeks of warnings that semi-molten rock was building up under the ground, the Icelandic Meteorological Office (IMO) said the eruption, at 8.23pm local time (2023 GMT) on Saturday, had opened a nearly 3km-long fissure in the earth between two mountains.

Lava was flowing mainly south and south-east at a rate of about 1km an hour overnight and could reach the ocean, the IMO said. Defensive dykes and barriers were being reinforced to stop the “significantly wider” lava bed wrecking the main coastal road.

By midday on Sunday, scientists said flows appeared to be slowing somewhat but still posed a danger to infrastructure in and around Grindavik. “Seismic activity has decreased since the eruption began,” the IMO’s Pálmi Erlendsson told the broadcaster RÚV.