Lava waves from a volcano in southeast Iceland that erupted on Saturday for the fourth time in three months slowed on Sunday, while barriers installed by authorities appeared to be successfully keeping the lava from infrastructure, including a nearby fishing town, Reuters reported.

The eruption – the fourth since December – began on Saturday night, spewing rivers of molten rock from a fissure about 3 km long, roughly the same size and in the same location as the last eruption in February.

“The eruption was quite energetic and quantitative, larger than the previous eruption. So the lava flowed quite fast,” Haldor Geirsson, associate professor at the University of Iceland’s Institute of Earth Sciences, told Reuters.

Authorities had warned for weeks that an eruption was imminent on the Reykjanes peninsula, south of Iceland’s capital Reykjavik, as magma accumulated underground.

Live video on Sunday morning showed lava flowing just a few hundred meters from Grindavik, a fishing town of about 4,000 residents that was evacuated during the eruption in November and again during the latest eruption in February. Several residents who have since returned home were evacuated on Saturday, public broadcaster RUV reported.

“The lava flow rate is getting lower and lower,” Geirsson said. “Most of the flows are heading east of the city, towards the sea, so it looks like the barriers are doing the job they were designed to do.”

Swarzengi Geothermal Power Station, which may be at risk due to lava

Authorities were also monitoring lava flow toward the peninsula’s Svartsengi geothermal station, the Icelandic Meteorological Service said. The plant, which supplies electricity and water to nearly 30,000 people, was evacuated and protective barriers installed.

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

Around noon on Sunday (12:00 GMT), activity in the fissure subsided and lava was flowing from three locations, police said in a statement.

Keflavík Airport and Iceland’s regional airports were not affected and continued to operate at full capacity, airport operator Isavia’s website said on Sunday.

The nearby Blue Lagoon geothermal resort, one of Iceland’s top tourist attractions, was closed, as it had been during previous eruptions.

The eruption in February cut off heating for more than 20,000 people as lava flows destroyed roads and pipelines.

Iceland has more than 30 active volcanoes, making the island a favorite destination for volcano tourism, a niche segment that attracts thousands of thrill-seekers.

In 2010, ash clouds from the eruption of the Eyjafjörður volcano in southern Iceland spread over large areas of Europe, canceling about 100,000 flights and forcing hundreds of Icelanders to flee their homes.