However, the danger is that the small volcano is just the beginning and that it will trigger the far more powerful volcano of Katla, which nestles beneath Myrdalsjoekull.
“That has to be on the table at the moment," Dave McGarvie, senior lecturer at the Volcano Dynamics Group of the Open University, said. “And it is a much nastier piece of work.”
Icelanders agree. "This could trigger Katla, which is a vicious volcano that could cause both local and global damage," Pall Einarsson, from the University of Iceland, said.
Tremors around Eyjafjallajokull were first recorded in early March, but precise prediction of volcanic eruption is difficult, even with the high-tech equipment available to Icelandic geologists.
Now that it has happened the only basis for prediction is history — and that does not look good.
"Eyjafjallajokull has blown three times in the past thousand years," Dr McGarvie told The Times, "in 920AD, in 1612 and between 1821 and 1823. Each time it set off Katla." The likelihood of Katla blowing could become clear "in a few weeks or a few months", he said.
Iceland is built on a volcanic rock on the Atlantic's mid-oceanic ridge and it has grown used to eruptions. The southern village of Vik, close to the current eruption, has for centuries had an escape plan in which everybody runs up to the church, which is built on high ground. They know that if Katla erupts flooding will follow.
The island's worst eruption in modern times was in 1783, when the Laki volcano blew its top. The lava shot to heights of 1.4 kilometres and more than 120 million tonnes of sulphur dioxide was released into the atmosphere.
A quarter of the island's population died in the resulting famine and it transformed the world, creating Britain's notorious "sand summer", casting a toxic cloud over Prague, playing havoc with harvests in France — sometimes seen as a contributory factor in the French Revolution — and changing the climate so dramatically that New Jersey recorded its largest snowfall and Egypt one of its most enduring droughts.