Thousands evacuated after eruption

According to a report in The Times newspaper, the "scale and strength of the volcanic outflow were greater than scientists had expected", with "intense seismic activity wrenching open" a 3.5 km crack that spewed out enough lava "to fill an Olympic swimming pool every 30 seconds".

Local police raised their alert level and the country's civil defense warned people not to approach the area while emergency personnel assessed the situation, reported the Reuters news agency.

An eruption in Iceland in 2010 resulted in a volcanic ash plume soaring several kilometers into the atmosphere, causing widespread air travel disruption for several days.

Volcanologist Evgenia Ilyinskaya told the BBC volcanoes in southwest Iceland are "physically not able to generate the same ash clouds "as were seen in 2010, suggesting a similar level of disruption will not happen.

Robin Andrews, a volcanologist, told The Times gas pollution from the eruption would be "mild to moderately unpleasant" in some areas.

He said sulphur dioxide is a colorless, pungent gas that "can cause some mild respiratory discomfort, but only in very high concentrations and if you have a pre-existing respiratory condition like severe asthma", adding that if it lingers "it can be quite unpleasant and it can cause acid rain", but would not cause harm and would not affect agriculture.

He added: "I haven't seen anything that screams that this is going to be a really severe issue. The lava is still the real threat."

Iceland is situated between the Eurasian and North American tectonic plates, a region known for its seismic and volcanic activity due to the opposing movements of the plates.