A state of emergency has been declared in southern Iceland after another volcanic eruption on the Reykjanes Peninsula - the fourth since December.

The eruption sent powerful and fast lava flows toward the mostly evacuated town of Grindavik late on March 16.

Lava has reached the town's eastern defences, but authorities have since stated that the activity around the fissure has significantly diminished.

The Icelandic Meteorological Office reported that the streams of lava were still flowing albeit at a slower rate on Sunday, March 17.

Vidir Reynisson, Director of Iceland's civil defence, said that all preparations for the flow of lava had been completed, with pools of lava gathering near defences posing a significant risk to infrastructure.

Geophysicist Magnus Tumi Gudmundsson flying over the affected areas in a helicopter, told local media that Saturday's eruption was the most powerful so far, with two lava streams moving west and south.

The Blue Lagoon, a popular geothermal spa, has been closed as a precaution, and between five and ten homes in Grindavik have been cleared.

Most residents have chosen not to return following a previous eruption in January that saw magma spread into the town, destroying three homes. Iceland, with 33 active volcano systems, sits over the Mid-Atlantic Ridge, the boundary between two of the largest tectonic plates on the planet.

The last time the Reykjanes Peninsula experienced a period of volcanic activity was 800 years ago, with eruptions lasting for decades.

Scientists believe the area is entering a new volcanic era that could last for decades or even centuries.

This latest eruption marks the seventh since 2021, highlighting the ongoing volcanic activity in the region and the challenges faced by residents and authorities as they navigate the impact of these natural phenomena.