Here’s a general rule of thumb: When a tabloid newspaper tells you that, without a doubt, a volcano is about to erupt, be skeptical immediately. Trust us – if there’s actually a risk, it will be all over the news, and scientists would be waving their arms quite vigorously.
The latest volcanic locale to get all the attention is Tenerife, a member of the Atlantic Ocean’s Canary Islands archipelago. It’s made up of several overlapping volcanoes, both of the shield type (like Hawaii’s Mauna Loa) or stratovolcanic (like Washington’s Mount St. Helens).
One of these stratovolcanoes – Teide – is showing some curious seismic activity as of late. The Volcanological Institute of the Canary Islands (INVOLCAN) have revealed that several swarms of low-energy earthquakes were detected at the base of the volcano back in October.
Teide is one of the 16 Decade Volcanoes, those that are considered to be the most dangerous to human populations. Its violent volcanic history, combined with the fact that millions of tourists visit it every year, certainly warrant attention.
So are we due for some fireworks, as the tabloids claim? No.
“The volcanic activity at Tenerife is the typical of a quiescent volcano,” INVOLCAN explain in a Facebook post.
“The volcano alert level is currently in GREEN position, the lowest one; therefore people can carry out their activities normally.”
In other words: don’t panic.
Seismic swarms – collections of closely-spaced earthquakes – are generally produced by two things. Either a fault network has reactivated and is slipping quite frequently or magma is moving through the crust.
Both happening underneath an active or dormant volcano are completely unsurprising. It’s literally what you’d expect them to be doing. It would be far more unusual if no seismic activity was observed.
So no, just because there’s been a seismic swarm, it doesn’t mean that a volcano is about to erupt. Unless the swarm moves towards the volcano’s vent and increases in magnitude and frequency day-on-day, you shouldn’t worry.
As it so happens, a similar series of earthquakes at Teide back in 2016 sparked a similar round of panic-inducing headlines, all of which were slammed by Tenerife officials as “irresponsible”. It didn’t erupt back then, and it’s incredibly unlikely to erupt now.
Even if it did erupt soon, though, there’s no guarantee it’ll be dangerous.
Take Yellowstone Caldera, for example. Sure, it’ll erupt again someday, but the chances of it exploding in a cataclysmic supervolcanic eruption are incredibly low right now; it’s erupted lava flows far more frequently, which although troublesome are far less deadly overall.
For what it’s worth, Teide’s last known eruption was in 1909, which registered as a 2 on the Volcanic Explosivity Index (VEI) scale. Although a repeat of this would be dangerous, it wouldn’t be devastating.