How Were The Galapagos Islands Formed? Volcanic Origins and More

Walking during Tintoreras Tour on Galapagos Islands, Ecuador (Isabela Island)

Over thousands of years, volcanoes erupted on the Galapagos Islands as a result of fires that originated in the Earth’s core. The volcanoes in the Archipelago are unique, though. The Nazca Plate, one of the plates that make up the Earth’s crust in the middle of the Pacific Ocean, is where the islands are located. This plate is unique in that it does not collide with any other plates.

Galapagos Island Map

A “hot spot,” defined by geologists as a location on Earth where the magma is hotter than it usually is, is what gave rise to the Galapagos Islands. The same happened in Hawaii and some other places on the globe.

The Galapagos Islands were formed by the volcanoes that resulted from the movement of the Earth’s crust over the hot spot. The hot spot is stationary while the plate shifts from west to east. As a result, geologically speaking, the eastern Galapagos Islands, such as Espanola and San Cristobal, are the oldest, while the western islands, such as Fernandina and Isabela, are the youngest.

Basaltic Lava

Los Tuneles landscape view

The Galapagos Islands are primarily made of basalt. This kind of rock is produced by basaltic lava.

Because basaltic lava is much more liquid than other types of lava, it travels farther and flattens out terrain much more quickly. The formation of shield volcanoes occurs in this way.

While the strongest basalts leave steeper, more rugged cliffs, volcanic ash that has been cemented with little tuff or pumice creates beaches. On Santiago Island, some lava flows from a century ago are still sterile, but on Isabela Island’s western shore, lava from a thousand years ago displays a wide variety of plants. You can visit some of the volcanoes, e.g. Sierra Negro.

Volcanic Activities in Galapagos

Red eruption at Sierra Negra Volcano Galapagos

There is no longer any volcanic activity in the eastern Galapagos Islands. Some of them are extremely old and on the verge of being submerged under the sea. For instance, Genovesa, a small island, is all that is left of a once-massive volcano. In fact, you might be able to go snorkeling in the volcano’s crater since it is no longer active.

On the other hand, because they are still above the hot spot, the western islands are still very active. The Isabela and Fernandina volcanoes continue to erupt frequently.

The underwater geography off of Isabela Island changed as a result of a sudden volcanic event in 1954, which is one notable volcanic event. The sudden elevation of a portion of the ocean floor led to the formation of Urbina Bay.

Captains of ships reported that the area smelled horribly of weeks’ worth of dead fish and other marine life. The sea creatures were unable to flee because it happened so quickly! Urbina Bay can be visited, and there are still some coral formations visible along the trail.

How Dangerous is the Volcanic Activity in Galapagos?

The volcanic activities in Galapagos are not totally dangerous. The majority of the tourist attractions in the Galapagos are located far from any potentially hazardous volcanoes.

However, they are risky for the animals because other animals might lose their habitat and giant tortoises could get burned by lava or hot ash. The rare Galapagos pink land iguanas, whose population and habitat are so limited that an untimely eruption could wipe them out, reside in Isabela’s Wolf volcano and are therefore considered to be in danger.

Bottom Line

Aside from its beautiful wonders, the Galapagos Islands have a unique and interesting history. Most tourists to the Galapagos come from all over the world to see the untamed wildlife or to scuba dive in the ethereally blue waters of the archipelago. But fewer people are aware of how fascinating the islands’ geology is in comparison to their wildlife. Make sure the check out the best things to visit while in the Galapagos

About the author

Oleg Galeev

I'm Oleg, and together with my wife, we've explored Ecuador and the Galapagos Islands, journeying through more than 20 cities (Quito, Cuenca, Banos, Tena, Puyo, Guayaquil, Riobamba, Otavalo, Mindo and more) and nearly every island in the Galapagos (including iconic ones such as Bartolome Island, San Cristobal Island, Isabela Island, Santa Cruz Island and more). In this blog, I give you my real thoughts about each place we visited. This info can help anyone planning a trip to the Galapagos Islands or mainland Ecuador. I'm just a traveler, not a tour company, so I'm not trying to sell anything. That means I'll tell you the truth—both the good and the bad — about traveling in Ecuador based on what we experienced.

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