Scientists have claimed that volcanoes are not really dormant and can be reawakened far more quickly than previously thought.
In just a matter of weeks they can go from calm and stable to spewing out lava onto the area around them, they said.
It had been accepted before that they could take years to make such a transformation.
The warning could force a rethink on resorts which rely on the draw of volcanoes to pull in tourists.
Many of the Greek islands have dormant sites, as does Italy while the Spanish island of Lanzarote was formed by an eruption.
In countries as far afield as Japan, however, tourists are taken on tours to walk in the huge craters which form where previous eruptions once happened.
The re-evaluation was carried out by Dr Alain Burgisser, a vulcanologist with French Orleans Institute of Earth Sciences.
He said the widely accepted theory that when a volcano’s magma chamber cools it could be years before it heats up with fresh magma could be wrong. Read More