Iceland Volcano
(Photo : AEL KERMAREC/AFP via Getty Images)
People gather to watch as molten lava flows out from a fissure on the Reykjanes peninsula north of the evacuated town of Grindavik, western Iceland on March 16, 2024.

A volcano in Iceland has started erupting for the fourth time in three months, leading to evacuations as the lava travels more than a half-mile an hour.

The eruption started Saturday night between Mt. Hagafell and Mt. Stóra Skógfell. Authorities say the fissure is about 1.8 miles long and formed quickly.

TOPSHOT-ICELAND-VOLCANO
People gather to watch as molten lava flows out from a fissure on the Reykjanes peninsula north of the evacuated town of Grindavik, western Iceland on March 16, 2024.
(Photo : AEL KERMAREC/AFP via Getty Images)

The Icelandic Met Office says if the eruption continues at the same rate the lava could reach the ocean. Crews constructed barriers in an effort to stop it from crossing the main road along the peninsula's southern coast, the Associated Press reported.

Web camera images and aerial photographs from a helicopter lead authorities to believe the eruption could be larger than the three previous fissure eruptions from the Sundhnúkur crater row.

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The skyline of Reykjavik is against the backdrop of orange coloured sky due to molten lava flowing out from a fissure on the Reykjanes peninsula north of the evacuated town of Grindavik, western Iceland on March 16, 2024.
(Photo : HALLDOR KOLBEINS/AFP via Getty Images)

A state of emergency was put into effect in the area of the Reykjanes Peninsula where the lava is flowing and a few houses were evacuated, the BBC reported.

The last time the peninsula had volcanic activity was 800 years ago. In that period, the eruptions reportedly went on for decades.

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People on the outskirts of Reykjavik take pictures and selfies with the orange coloured sky as molten lava flows out from a fissure on the Reykjanes peninsula north of the evacuated town of Grindavik, western Iceland on March 16, 2024.
(Photo : HALLDOR KOLBEINS/AFP via Getty Images)

Grindavik's 3,800 residents were first evacuated in November after earthquakes and thermal fissures were detected.

On December 18, the volcano erupted, sending lava flowing away from the town, which allowed residents to briefly return to their homes by December 22 after volcanic activity weakened.