To find the enchanted islands, you must leave Ecuador on the South American mainland and travel west for 1,000 kilometers (620 miles). Follow the Equator to an isolated clump of islands we know as the Galápagos.

From the air, some islands look like green gems springing up from the deep blue ocean. Other islands look barren. You can try counting them. There are 13 large islands (12 shown on our map), six smaller ones, and scores of unnamed rocks. How did they form, so far away from the rest of the world? The answer lies in Earth’s crust. Or, more specifically, the tectonic plates that make up Earth’s crust and move in relation to each other.

From the Depths

The Galápagos Islands sit on top of one of the most active volcanic regions on Earth. These islands lie on the Nazca tectonic plate, which is touched by four other plates.

This isolated place in the ocean rests above a hot spot in Earth’s crust where a column of hot magma rises. When the magma reaches the surface, lava spews out. The lava piles up. Eventually, a volcano forms.

This is how the first Galápagos island, Española, formed more than three million years ago. Each Galápagos island is volcanic in nature. The largest island, Isabela, was formed by six volcanoes that merged together.

This aerial view shows the volcanic craters that make up Isabela Island.

On the Move...

Volcanic activity explains how one island formed, but how were the other islands formed? Think back to the plates. Remember, they move. The Nazca plate moves toward the South American plate at a rate of around 7 centimeters (2.7 inches) per year.

The plates move, but the hot spot does not. Over time, Española was carried southeastward along with the Nazca plate. Then a new island—San Cristóbal—formed on the hot spot.

The layout of the islands reflects the speed and direction of the moving plate. The Galápagos’ youngest island, Fernandina, sits on the hot spot now. It’s a mere 700,000 years old. Its volcano erupted in 2009, 2017, and 2018.

map of Earth's tectonic plates

...Over Time

In a million years’ time, Fernandina will have moved 60 kilometers (37 miles) southeast, and new islands will have formed in its old place.

The older eastern islands—including Genovesa, Floreana, San Cristóbal, and Española—will have shifted as well.

Moving Islands

It took millions of years for the Galápagos Islands to form. As the Nazca plate moves, new islands form over the hot spot. Old islands eventually fall away into the sea.