With volcanic activity being reported everywhere from Iceland to Italy, should we be concerned that a catastrophic event is looming?
REVIEW
Back in November, thousands of small earthquakes rocked southwest Iceland as magma rose towards the surface along a 14km (8.5-mile) fracture near the Svartsengi geothermal power plant. Molten rock opened wide fractures that sliced through the small town of Grindavík. The ground continued to swell and, at the time of writing, an eruption remains possible.
At around the same time, Mount Etna on the Italian island of Sicily exploded, dumping ash on nearby towns.
That’s not all. Across the world, 45 other volcanoes continued to rumble, including Mayon and Taal in the Philippines, Santa María in Guatemala, Nevado del Ruiz in Colombia and Anak Krakatau in Indonesia. That last volcano is rising again following a major collapse in 2018, when it created a tsunami that killed more than 400 people.
HOW ACTIVE ARE THESE VOLCANOES?
It’s possible that the magma rising near Svartsengi may not erupt at all, but instead will solidify beneath the surface. If it does reach the surface, though, it’s likely to be in typically Icelandic style: very fluid lava will pour out of long cracks, occasionally solidifying into spectacular cones.
The recent eruption of Mount Etna marks business as usual at a volcano that’s always sparking minor firework-like displays, pumping out lava or launching columns of ash high into the atmosphere.
Activity at the rest of the world’s currently active volcanoes is – for the time being, at least – relatively inconsequential, involving minor explosions, lava outbursts or the formation of small pyroclastic flows (rapidly moving flows of hot ash and gas). Only people living on or close to the volcanoes face a real threat, and exclusion zones have been put in place in those spots in case activity escalates.
WHY ARE ALL THESE VOLCANOES ERUPTING?
Volcanoes erupt when fresh magma produced in the Earth’s mantle reaches the surface, either via an open vent or by breaking through the rock above it.
This actually happens all the time. About 70 volcanoes erupt every year, with around 20 erupting on any one day. Iceland alone has an estimated 30 volcanic systems – discrete zones where eruptions can occur, either from an established cone or from new fissures (cracks in Earth’s surface). In fact, Iceland, which straddles the line where the North
