The Eyjafjallajökull volcanic eruption in 2010 caught many people off guard and resulted in severe disruption to air travel across western and northern Europe for a week. Europe has other volcanoes that are active and occasionally disruptive but one with the potential to cause serious problems is the Teneguía volcano in the area of Cumbre Vieja on the Canary Island of La Palma.

In mid-September, the Spanish authorities raised the volcanic hazard alert level after registering more than 4,000 earthquakes in recent days. Experts monitoring the situation have reported that there could be a volcanic eruption in the coming days or weeks. There are no clear signs yet of an imminent eruption but local officials warn that ‘everything indicates that it will evolve to earthquakes of greater magnitude that will be more intense and felt more by the population’.

La Palma experienced its last eruption in October 1971 when the Teneguía volcano ejected lava for more than three weeks across the southern part of the island. The subsoil of La Palma had remained dormant until 2017 when seismic activity began that has intensified sharply in 2021. Although almost all of the quakes have been small in magnitude, four have been recorded as being above magnitude 3. The first movements occurred at 20km of depth but were 6-8km below the surface by 16 September. Another sign of a possible impending eruption is that the island has bulged 4.5-6cm recently due to pressure beneath the surface, and in the area where the quakes are concentrated.

The wider danger

The Cumbre Vieja rift is one that has been studied extensively because of the danger of a large collapse of the flank of the volcano into the sea setting off a tsunami. In 1999 two scientists predicted a mega-tsunami could be caused that would rush across the Atlantic. This wave was predicted to reach the eastern seaboard of North America in about six hours by which time the initial wave may have subsided into a succession of smaller ones each about 30-60m high.

There has been controversy, however, about the threat presented by any Cumbre Vieja collapse, with some other reports suggesting that landslides may be gradual and therefore may not generate tsunamis of significant magnitude. In the 2017 incident, a series of low-magnitude earthquakes were recorded on the west flank of the Cumbre Vieja but at an average depth of around 21km; they were largely ignored as the impact was minimal. In the past, flank collapses on smaller volcanic island have created waves not large enough to be considered mega-tsunamis but still large enough to cause major damage; an example is the Sunda Strait tsunami in Indonesia in 2018.

Risk to supply chains

Globalisation supports the clustering of critical infrastructure systems, sometimes in proximity to lower magnitude volcanic centres. In this emerging risk landscape, moderate volcanic eruptions might have cascading, catastrophic effects. Risk assessments ought to be considered in this light.

A paper by academics from the University of Cambridge Centre for the Study of Existential Risk highlights seven global pinch points where a clustering of global critical systems converges with regions of volcanic activity. The North Atlantic is one of those pinch points.

The authors concluded: 'Unlike super-volcanic eruption scenarios where we have little opportunity for prevention, we can work to reduce the fragility and exposure of our critical systems to rapid-onset natural events, and ultimately increase our resilience to global catastrophic risk.’