Formation and main eruptions

All the islands of the archipelago of the Azores, without exception, have a volcanic origin. Their formation is related to the triple joint of the three tectonic plaques: North American, Euro-Asiatic and African.

The oldest island, over 8 million years, is the island of Santa Maria. It's the only island of the archipelago where we can find fossils because, for some time, the island was underwater.

Pico island is the youngest island to be formed, with an approximate age of 300 thousand years. This island is also known as "the grey island" due to the volcanic eruption that originated huge fields of volcanic lava. The huge volcanic cone, Pico Mountain with 2351 meters, is an active volcano that is only dormant in one of the most appealing places of the archipelago.

Corvo Island is the smallest island of the archipelago, with just 6.24 kilometers in length and 3.99 kilometers in width. Corvo and Flores islands form the Ocidental group of the archipelago. They are the western islands with beautiful and natural landscapes, as Rocha dos Bordões at Flores island, originated by the solidification of basalt in high vertical stripes, and the Caldeirão at Corvo island, a huge volcanic crater that formed the island.

Faial island, one of the islands of the Central group of the archipelago, was the stage for one of the biggest historic eruptions of the archipelago. In 1957, a huge seismic crisis occurred that lasted for 12 days, and over 200 seismic events happened, due to the eruption of the Capelinhos Volcano, with its main crater located about 1 kilometer of west part of the island, and during which tons of grey ashes were projected and accumulated increasing the size of the island.

São Miguel is the island with the most amount of active volcanoes, starting with the Sete Cidades volcano, the volcanic faults of Picos and Congro, the volcano of Água do Pau where Lagoa do Fogo is and the volcano of Furnas. The first eruptions of the island started at the beginning of its settlement, at Sete Cidades volcano in 1444. On the 3rd of September of 1630, one of the biggest volcanic eruptions was recorded in the Azores, at Furnas volcano.

São Miguel is the biggest island of the Azores, but not all the island was formed at the same time, in which we can split it in six different stages.

  • Volcanic complex of Nordeste, extinct, approximately 4 million years old. Known for its vegetation and beautiful flowers, such as their hydrangeas and azaleas, which decorate the sides of the roads of the town. It is here where you can find the highest point of the island, Pico da Vara, 1103 meters high with a beautiful view over the island;
  • Volcanic complex of Povoação, extinct, approximately 3 million years old. Location on the island where the first settlement took place and first church;
  • Volcanic complex of Furnas, approximately 800 thousand years old. Known for its thermal waters that form pools of medicinal and natural water pools. Last eruption in 1630;
  • Volcanic complex of Sete Cidades, approximately 800 thousand years old. It is situated inside of a crater with a 5 kilometer diameter possessing one of the most beautiful lakes inside of volcanic caves, Lagoa Verde and Lagoa Azul.
  • Volcanic complex of Fogo, 290 thousand years old. Last eruption was in the year of 1563, at Lagoa do Fogo, days after at Pico do Sapateiro, known as Pico Queimado since then.
  • Volcanic complex of Picos, approximately 50 thousand years old, joining the two islands that existed before, forming the island of São Miguel. Last eruption on this complex was in 1652.

The first capital of the Island of São Miguel was Vila Franca do Campo, lost its status after being buried because of a violent earthquake in 1522, after which it was replaced by Ponta Delgada.

Nowadays, the green island, as it is known, has six municipalities: Lagoa, Nordeste, Ponta Delgada, Vila da Povoação, Ribeira Grande e Vila Franca do Campo.