The Azores archipelago sits on top of a monster. In this area of remote ocean three of the planet’s vast tectonic plates meet and grind together, with some parts of the earth’s crust plunging underneath, heading deep below, while others crash into each other to create mountainous lumps. All this means there’s loads of lava. Over millions of years the molten rock has bubbled up where the plates meet to create a line of volcanoes, which make up the islands we see today.
The Azores wouldn’t exist without all this violent ancient volcanicity. Let’s dive into the geology, see what’s in store for the landscape drama queens amongst us.
An overview of Azorean volcanic activity
The Azores archipelago sits near the triple junction of the Eurasian, American and African tectonic plates, around 900 miles from Europe and 2450-ish from the east coast of the USA. The islands sit on top of the mighty Azores Plateau, a lumpy and unusually thick area of the planet’s crust, and they’re relatively new geologically at just five and a half million years old.
Some of the islands popped up before others. In sequence, Santa Maria is the oldest, then São Miguel , Terceira, Graciosa, Flores, Faial, São Jorge and Corvo. Pico is the baby of the family at not much more than 250,000 years old.
The western islands of the Corvo and Flores sit on the North American Plate, the rest straddle the boundary between the Eurasian and African plates. As a result the Azores has a total of 26 volcanoes, eighteen on dry land and the rest underwater. The only island without an active volcano is Santa Maria.
The 36 million year old Terceira rift is still making its slow and steady way south, 350 miles long and the planet’s slowest spreading centre from a place where tectonic plate diverge. You won’t notice it moving at just 2 – 4mm a year. But these volcanoes, being mere youngsters, are far from extinct. The Azores volcanoes are dormant, waiting until the geological conditions are right. They may never erupt again or they might blow their top next week.
Luckily they’re showing no sign of waking up at the moment. The famous hot springs at Furnas are a sign that things are still pretty darned hot down there – and not that far down, either. The countless underground faults and rifts created by millennia of geological violence, and the resulting rich volcanic soils, make this a green, lush place with magical varied fauna and flora set against some of the most dramatically beautiful landscapes on earth.
About the volcanoes of the Azores – Mount Pico
The towering Mount Pico volcano is part of the Madalena Volcanic Complex, one of three making up the island. Think of it like three pimples and you get the picture! Mount Pico erupted in 1562, 1718 and 1720 and has been honoured with the title ‘One of the 7 Natural Wonders of Portugal’.
She stands 2351m high, taller than any mountain here or on mainland Portugal, with a 700m perimeter. Just 30m deep with a 70m high volcanic cone, it’s unmistakeably volcanic. The colourful flowers, the archipelago views, the endless Atlantic, the vistas from the top are incredible. Best of all it is accessible by car as high up as 1200m, shortening the long, breathtaking clamber to the rim.
Big drama in 1808 at Bocas de Fogo
Bocas de Fogo means ‘Mouths of Fire’ and that’s what people saw back in 1808 when it last blew things sky high. On São Jorge Island, near Urzelina, the eruption kept going from May through June 1808, causing widespread destruction and creating a brand new, steaming field of dense black basalt rock.
The enormous Sete Cidades Massif
The Sete Cidades volcano, translated as the Seven Cities volcano, is the star of São Miguel, at the easterly end of the Terceira rift axis we mentioned earlier. The volcanic area extends to 110 square km and there’s a slow-growing blob of boiling hot lava extending to about 70 cubic km underneath, currently about 210,000 years old.
Four gorgeous lakes and a perfectly circular 3 mile diameter caldera will totally blow your mind, signs of an old volcano almost too big and scary to imagine. Two of the crater lakes are particularly famous for their vivid colour: one blue and one green. Reaching 400m above sea level, there are fascinating cones, lava domes and flows to marvel at in every direction.
Volcanic eruptions in the Azores
The first time humans saw a volcanic eruption here was on Furnas between 1439 and 1443, at around the time Sao Miguel island was first being colonised. Since the 1400s there have been 28 registered volcanic eruptions in the Azores, fifteen on dry land and 13 underwater.
The last big blow-out, at the Vulcão dos Capelinhos, erupted just off the coast of the island of Faial in 1957 but there’s been lower key volcanic activity in the sea mountains and submarine volcanoes off the coast of Serreta and in the Pico-São Jorge Channel since then.
The islands feature masses of fascinating sea caves, lava tubes and other volcanic treasures. Look out for the Gruta das Torres, Algar do Carvão, Gruta do Natal, and the Gruta das Cinco Ribeiras. Around the coasts you’ll find old lava fields, for example on the coast of Feteiras, Faial, the Mistério of Prainha and São João on Pico.
Since humans settled on the islands there hasn’t been much volcanic activity, with nothing much other than sporadic eruptions. There was a new island at one point, called Sabrina. It popped out of the foaming ocean just off the coast of Sao Miguel then sank back under the waves.
The famous 1522 earthquake
In 1522 the capital of Sao Miguel, Vila Franca do Campo, was flattened by a powerful earthquake and accompanying landslide that killed five thousand. Afterwards they moved the capital to Ponta Delgada and rebuilt Vila Franca do Campo on the original site, now a vibrant fishing and yachting destination.
Recent Azores volcanic activity – April 2022
Experts were baffled in 2022 when unusual seismic activity kicked off on the Azorean island of Sao Jorge, lasting more than two weeks. The island was hit by just under 27,000 small tremors in a row, 5-8 miles down, sparking fears that a volcanic eruption or earthquake could be on the way.
This was unusual for Sao Jorge, which doesn’t tend to get the multiple tremors you get on the other islands, where they’re just part of everyday life. Going from a very small number of earthquakes to thousands was described by scientists as ‘extraordinary’.
At the time the official volcanic alert was Level 4, revealing a ‘real possibility’ of an eruption. They detected some deformation of the ground, which also puzzled experts, but the geology of the island and its surrounding sea floor isn’t well understood so there are plenty of mysteries yet to solve down there.
One geologist said it was unclear which sort of eruption could take place. Previous events on Sao Jorge in 1580 and 1808 came with the same kind of deadly pyroclastic flows of hot gas, dust and volcanic rock that decimated Pompeii in 79AD, volcanologists were keen to keep an eye on the developing mystery. Right now? As we write, all is quiet and calm. Phew!
Tours in the Azores – Drama personified
Here are some excellent adventures for you to enjoy while on one of the world’s most beautiful, exotic and dramatic island chains. Happy days.
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