The aviation color-code has been raised to red after a second lava eruption started early Sunday morning in Holuhraun lava field, north of the Bardarbunga volcano in southeastern Iceland.
According to Iceland's Meteorological Office (IMO), scientists on the scene observed the eruption at about 5:15 a.m. (0515 GMT) Sunday morning, in the same rift as Friday.
They believed the rift was longer than in Friday's eruption, extending towards north and south. The effusive eruption was very calm as it could be hardly detected by seismometers.
Armann Hoskuldsson, one of the volcanologists at the site, told local media the fissure was about 1,500 to 1,800 meters long and the eruption produced 50 to 60 meters high lava fountains.
The IMO has raised the aviation color-code to red. It warned a strong gale, more than 20 meters per second, was expected in most parts with strong gusts near mountains and heavy rain was also expected in the southeast with a risk of mudslides.
A small no-fly zone, which reaches from ground to 6,000 feet altitude around the eruption site, was set by the Icelandic Transport Authority. But all airports in Iceland remained open.
A fissure eruption started in Holuhraun lava field north of Dyngjujokull early Friday morning, and lasted for three to four hours.