In the eastern North Atlantic Ocean, hundreds of miles off the coast of Europe, the continents are slipping away from each other. Three of the “plates” that make up Earth’s crust are sliding apart, allowing molten rock to push up from below, building new crust. That process is also building a chain of islands that’s one of the most “active” spots on the planet.
The Azores consists of nine major islands. They stretch across about 350 miles, and are home to a quarter of a million inhabitants.
The first island in the chain rose from the ocean depths about eight million years ago. The most recent appeared just a quarter of a million years ago.
The Azores formed at the junction of the North Atlantic, Eurasian, and African plates. They’re spreading apart at the Mid-Atlantic Ridge -- a massive underwater mountain range built by molten rock from below the crust. A pool of especially hot rock may form plumes that push up along the junction between the plates, building the islands.
The activity isn’t limited to the islands, though. Scientists have discovered many underwater volcanoes as well -- some still active, and some extinct. They’ve also found large fields of hydrothermal vents -- fountains of hot, mineral-rich water that percolate from deep below the ocean floor.
Many volcanic eruptions and earthquakes have rattled the Azores over the centuries. The most recent major eruption came in the 1950s, and built a small, temporary island -- a fleeting bit of land where the continents are moving apart.