The Azores archipelago consists of nine widely separated islands. Like all islands in the Atlantic, they are of volcanic origin and lie between Europe and North America. Flores also forms the western end of Europe.
Plate tectonics:
The Azores lie on the Mid-Atlantic Ridge, a geologically extremely active zone. Deep beneath the ocean's surface, three tectonic plates of the Earth's crust collide here. These plates are drifting apart, constantly pushing new material upward from the Earth's interior. Over millions of years, this created an underwater mountain range, the highest peaks of which, in the form of the nine Azores islands, rise from the sea.
The islands lie between the American Plate to the west and the Eurasian and African Plates to the east. Corvo and Flores The North American Plate moves away from Europe by about 1,5 centimeters annually due to continental drift. The islands of the Central and Eastern Groups are moving eastward at the same rate. This friction creates tension and earthquakes. As a result, the thin crust can rupture and magma can erupt – as happened around four million years ago when the nine islands, with a total area of 2.333 square kilometers, were formed.
Island groups:
the Eastern Group: Sao Miguel, Santa Maria
the central group: Terceira, Graciosa, Sao Jorge, Faial, Pico
the Western Group: Flores, Corvo
Corvo in the northwest Santa Maria In the southeast, approximately 550 km. The time difference in the Azores compared to Coordinated Universal Time (UTC) is one hour behind. Central Europe is therefore two hours ahead.
The islands were formed by a series of volcanic eruptions. They lie on the Mid-Atlantic Ridge, where the North American Plate (Flores and Corvo) on the Eurasian (Sao Miguel) and the African Plate is encountered. Santa Maria lies on its own small microplate of the Azores.Faial, Pico, Sao Jorge, Graciosa and Terceira lie on a transverse fault.
Santa Maria At approximately 80 million years old, it is the oldest island and is located furthest from the Mid-Atlantic Ridge. Pico The youngest island is in the middle. Sao Miguel The oldest basalt rocks, dating back approximately 4,2 million years, are found here. The Earth is still partially active today. Nine volcanic eruptions were recorded in the 20th century alone. Most of these, however, occurred underwater. This makes the Azores particularly interesting for geologists.
Volcanology:
Countless volcanoes dominate the landscape. These are stratovolcanoes, usually with steep flanks. The various layers of lava and tuff were formed by the ejection of lava and cinders. The larger caldeiras also emerged from the volcanic craters. The original volcanic cone collapsed after an explosion. Small crater lakes have usually formed at the bottom of these drainless volcanic craters. While the slopes on the outside slope gently downwards, the crater walls inside the caldeiras are usually very steep.
Most of the smaller volcanic cones in the Azores are of the Stromboli type. They therefore possess a certain explosive power. Eruptions can produce ash columns up to 1 km high. The volcanic cinder cones are often used as quarries. The porous gravel (begaco) extracted from them is ideal as a building material. This is used, among other things, to cast the hollow blocks needed for house construction.
Plinian-type volcanoes are much more dangerous. Their trachytic lava is so viscous that the gases can only escape explosively. Eruption columns therefore reach up to 20 km high. An eruption can therefore devastate large areas. One example is the Caldeira on Faial.
On Terceira In the highlands, one can observe several irregularities in the landscape (hornitos). These masses of rock were ejected from volcanic vents. They are therefore called conical peaks.
For TourThe islands' geological features are evident in the form of volcanic craters, towering cone volcanoes, steaming hot springs, mud baths, solfataras, fumaroles, and magnificent basalt formations. Eruptions of the still-active volcanoes are frequent. Although they occur below sea level, the tremors are felt on the islands. For example, an earthquake on the island in 1998 caused widespread destruction. Faial Entire villages. On average, there is a major earthquake every ten years, and a volcano erupts every 100 years. The Azores now have an early warning system for earthquakes.
Ants:
Besides the nine islands, there are also the uninhabited Formigas. These small islands lie between Santa Maria and Sao Miguel, about 35 km off the coast of Santa Maria.
Some of the small islands rise only a few meters above the sea and are all uninhabited. They are considered a diving paradise, although diving is now restricted. The Formigas Islands have been declared a nature reserve. Divers and anglers now require a license. Many breeding birds nest here, and the underwater fish population is so abundant that you might even hook a big one. In 1995, the "women's world record for swordfish fishing" was set here with a swordfish weighing 480 kg and measuring 4,7 meters.
The Formigas are feared by sailors. Many a captain has been shipwrecked here. A lighthouse now marks the archipelago, its lights visible at night even from Santa Maria can be seen.
Facts and Figures
Total area: approx. 2.326,8 km² Economic zone: 984,3 km² Sao Miguel is the largest island (747 km²).
Corvo is the smallest island (17 km²).
Location: between the 36th and 39th parallels latitude, from 39°43' to 36°55' north latitude, between the 25th and 33rd parallels longitude. Shortest island distance: between Pico and Faial It's only 6 km.
Greatest distance between islands: between Santa Maria and Corvo They are approximately 550 km away.
Distance: from Portugal: approx. 1.500 km; from North America: approx. 4.000 km; Highest elevation: Pico, 2.351 m. It is also the highest mountain in Portugal.
