• Matthew Blackett

Are the Canaries really that hazardous!!??

We need to talk about the Canary Islands. For decades, this chain of islands has been a regular go-to destination for millions of Northern Europeans, with their year-round sunshine, beautiful beaches and relatively short flight times. What many of these visitors may not known however (at least, not until they arrived visit) is that these islands really are volcanoes and that they really are active.

For most visitors, the closest they’ll get to experiencing anything volcanic during their stay in the Canary Islands are the stunning vistas or a meal cooked over a deep source of geothermal heat (as is possible in #Lanzarote's Timanfaya National Park). For the more adventurous however, and with some planning, it is possible to visit the peak of #Tenerife's Mount #Teide (at an altitude sickness-inducing 3700 m the highest peak in) and witness the active volcano steaming away. This rather hand-off experience all changed on Sunday 19 September 2021 when the volcanic complex on the most westerly Canary Island, La Palma, started to effuse lava.

Mount Teide, Tenerife

Me atop Teide!

The currently active volcanic complex on La Palma is within the island’s Cumbre Viejo National Park and fortunately the lava flows we are currently seeing did not come as a complete surprise to Spanish scientists at @INVOLCAN. In the preceding week, seismic activity on the island had stepped up a notch in terms of the number and magnitude of shallow-focus earthquakes recorded; the ground had also started to bulge. Such observations are often a sign of rising magma and in this case, that was shown to be true. This warning sign caused to scientists to raise the Alert Level of the volcano to Yellow (the second lowest level on a four-color scale) in surrounding municipalities on 14 September.

Rising depth and number of earthqukes on La Palma.

Rising intensity of earthquakes on La Palma.

So what's been happening?

On Sunday 19 September at just after 3pm, the a volcano within the Cumbre Vieja region erupted, initially with a small plume. This followed a 3.8M earthquake a few hours before which is thought to have been the event that opened the first effusive dyke.

Later in the day, several vents opened up, producing fire fountains and associated lava flows.

The eruption has continued unabated since starting on 19 September, with the extent as of 22 Sept shown below.

How dangerous is it?

Fortunately, the lava flows from this volcano are slow moving (around 700m/hr), meaning that evacuations were possible right after the eruption starded and in fact, shortly after these events played out, around 10,000 were evacuated. So there is little threat to life. These facts however, may provide only limited comfort to those who live in the flow’s path as there is little that can be done to prevent the destruction of anything in its way. There are also hazards posed to those nearby in terms of the significant volcanoes of SO being emitted.

One of the main concerns now is that if/when the hot lava meets the sea, intense but localised explisions may occur (much like the spatter that occurs when frozen food meets hot fat in a deep fat fryer). This potential hazard will depend on how much more lava is effused and how quickly it moves (i.e. will it solidify before making the sea).

Are the Canaries safe to visit?

It's probably advisable to avoid La Palma while all this plays out. The authorities have a lot to manage and could probably do without tourists popping over to view it (also check with FCO advice). It must be said however, that this marks the first volcanic eruption on La Palma since 1971 and indeed, the most hazardous and obvious volcanic activity in the Canaries in living memory. In 2012, an underwater eruption occurred off the coast of El Hierro but the impact above ground was minimal. We have to go back to 1909 however to witness volcanic activity on the main Canary Island of Tenerife.

The eruption of Chinyero Volcano on Tenerife in 1909 (from Di Roberto et al, 2016 and the National Heritage of Spain).

Only 24 people have succumbed to Spanish volcanic activity since the 15th century. One of the reasons for this is that the lava from these Canarian volcanoes does move so slowly. What has changed of late however, is that there are now significantly more people and infrastructure on the islands that are at risk during eruptive periods. Go back 60+ years and the Canaries were a quiet Spanish backwater whereas today, they are a major tourist hub and significant contributor to the Spanish economy. Fortunately, work continues to assess the volcanic hazard on the islands.

The islands will always remain volcanic and as we have seen, activity could recommence there at any time. What we have also seen however, is the good amount of monitoring is conducted on these Spanish islands, with changes being noted in the activity on La Palma several days before the eruption commenced. Well planned evaucations then followed. So tourists should not be put off from visiting the Canaries indeed, the volcanic nature of the islands might even be a draw for some. But such events should act as a reminder of the Earth’s ability to exert control over human activity at any time; we humans just need to continue to learn about and understand the Earth so that possible disaster events can be avoided.