The Blue Lagoon attracts thousands of visitors a day at its busiest times (Picture: AP)

One of the most popular tourist attractions in Iceland has temporarily closed after a series of small earthquakes sparked fears that a nearby volcano may erupt.

The Blue Lagoon spa, where bathers swim in distinctive turquoise water heated by geothermal energy, has been shaken by seismic activity every day for more than two weeks.

When the latest and strongest earthquake struck at around 1am today, guests at the hotels surrounding the spa rushed to get away.

Local taxi driver Bjarni Stefansson told the Associated Press: ‘There was a panic situation. People thought a volcanic eruption was about to happen.’

He said lava rocks had fallen on the roads close to the nearby volcanic mountain Þorbjörn, while the land in the surrounding region has risen by 9cm since October 27 – a sign an eruption may be on the way.

The Icelandic Met Office has said it is investigating whether seismic activity is approaching the surface, which would indicate magma is ready to burst out.

On its website, the agency said: ‘Presently, there are no signs that earthquake activity is becoming shallower.

‘However, the situation could change quickly, and it is not possible to exclude a scenario involving a lava-producing eruption in the area north-west of Þorbjörn.’

The Blue Lagoon can be found around 30 miles west of the Icelandic capital Reykjavík, a location that has helped it attract more than a million visitors a year recently.

The Icelandic Met Office said a magnitude 4.8 earthquake struck the area at 12.46am (Picture: AP)

Scientists have said the most likely course of events would see an eruption taking place in a remote valley, without any danger to visitors – though the storage chamber currently filling with magma could burst less than 1.8 miles from the lagoon.

The town of Grindavík and the pipelines that are used to heat its buildings with geothermal energy could also be under threat in the worst-case scenario.

Volcanologist Thorvaldur Thordarson said: ‘We need to be prepared for the worst. Magnitude 5 earthquakes, such as the one last night, are known to precede eruptions.’

Explaining the reason for the closures, the Blue Lagoon’s website says: ‘We aim to mitigate any disruption to our guests’ experiences and alleviate the sustained pressure on our employees.’

It will remain shut until 7am on November 16, the statement said.

Guests fled from the nearby hotels this morning after they were woken by an earthquake.