REYKJAVIK - Lava flows from a volcano in south-west Iceland that lit up the night sky on March 16 slowed the next day, while man-made barriers appeared to be successful in steering the lava away from infrastructure, including a nearby fishing town.

The eruption – the fourth since December – began on the evening of March 16, sending fountains of molten rock soaring from a roughly 3km-long fissure, about the same size and at the same place as the last eruption in February.

“The eruption was quite energetic, and there was a lot of material coming out, more than in the previous eruption. So lava was flowing quite fast,” Associate Professor Halldor Geirsson of the Institute of Earth Sciences at the University of Iceland told Reuters.

The authorities had warned for weeks that an eruption was imminent on the Reykjanes peninsula just south of Iceland’s capital Reykjavik, as magma had been accumulating underground.

Live-stream video early on March 17 showed lava flowing just a few hundred metres from Grindavik, a fishing town of some 4,000 residents that was evacuated during an eruption in November and again for the last eruption in February. A few residents who had since returned home were evacuated on March 16, public broadcaster RUV reported.

“The rate of the lava flow is getting lower and lower,” said Prof Geirsson. “Most of the flow is going east of the town towards the sea, so it looks like the barriers are doing the job they were designed for.”

The authorities were also monitoring lava flowing towards the peninsula’s Svartsengi geothermal power plant, the Icelandic Meteorological Office said.

Volcanic outbreaks in the Reykjanes peninsula are so-called fissure eruptions, which do not usually cause large explosions or significant dispersal of ash into the stratosphere.

Around noon local time on March 17, the activity on the fissure had decreased and lava was flowing from three places, the met office said in a statement.

Keflavik Airport and regional airports in Iceland were not impacted and remained fully operational, airport operator Isavia’s website showed on March 17.

The nearby Blue Lagoon geothermal spa, which is one of Iceland’s major tourist attractions, closed as it did during previous eruptions. The February eruption cut off heating to more than 20,000 people as lava flows destroyed roads and pipelines. REUTERS