The eruption started taking place in the Geldinga Valley on the Reykjanes Peninsula on 19 March, attracting thousands of Icelanders who flocked from across the country to see the spectacle.
Authorities set up the trail to cope with the huge volume of visitors – an estimated 10,000 since Friday.
“People were hiking from many different directions into the area,” Agust Gunnar Gylfason, project manager at the Department of Civil Protection and Emergency Management, told Reuters.
Footage taken of the volcano from overhead shows lava bubbling and spectacular jets of magma shooting into the sky.
Volcanology professor at the University of Iceland, Thorvaldur Thordarson, described it as the “perfect tourist eruption”, but added: “With the caveat though, don’t go too close.”
The area is currently being patrolled to prevent tourists from wandering into unsafe spots. Several people have already needed rescuing after arriving without proper food or clothing and falling foul of the weather.
It’s unknown how long the phenomenon might last.
“It could end tomorrow or it could still be going in a few decades,” said Gylfason.
Lava is currently flowing at a rate of between five to 10 cubic metres per second.
The Geldinga Valley eruption is the first on the Reykjanes Peninsula in almost 800 years.
The area began rumbling with increased seismic activity 15 months ago, and the tremors increased dramatically last month.
Over the past few weeks, the area has been disturbed by around 50,000 small earthquakes, dozens of them magnitude four or stronger, the Met Office said.
Scientists flew over the Geldinga Valley eruption on Saturday morning and estimated the eruptive fissure was about 500 meters long (1,640 feet.) The two streams of lava were about 2.5km from the nearest road.
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