How Were The Galapagos Islands Formed? Volcanic Origins and More
Quick Facts About The Formation Of The Galápagos Islands
| Origin | Volcanic: the Galápagos hotspot under the Nazca Plate |
|---|---|
| Oldest islands | The eastern islands, San Cristóbal and Española, roughly 3 to 4 million years old |
| Youngest islands | The western islands, Fernandina and Isabela; Fernandina is under 1 million years old |
| Main rock | Basalt, from fluid lava that builds shield volcanoes |
| Recent eruptions | Sierra Negra in 2018 and Fernandina's La Cumbre in 2024 |
Our Take On The Formation Of The Galápagos Islands
The Galápagos Islands sit on the Nazca Plate in the Pacific Ocean and were formed by volcanoes rising from a hot spot, a place where the magma is hotter than usual. The hot spot stays still while the plate moves from west to east, so the eastern islands such as Española and San Cristóbal are the oldest and the western ones, Fernandina and Isabela, the youngest. The eastern islands are roughly 3 to 4 million years old, while Fernandina is under 1 million years old. The islands are made mostly of basalt from fluid lava that builds shield volcanoes.
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. Along its eastern edge this plate slides beneath the South American Plate.
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.
How Does Basaltic Lava Shape The Formation Of The Galápagos Islands?
The Galápagos Islands are primarily made of basalt, a rock produced by basaltic lava. Being more liquid than other lavas, it travels farther, flattens terrain and forms shield volcanoes. Cemented volcanic ash with tuff or pumice creates beaches, while stronger basalts leave steeper cliffs. Some Santiago lava flows remain sterile, and Sierra Negra can be visited.
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 Negra.
Are The Galápagos Islands Volcanic?
Yes, the Galápagos Islands are volcanic. The eastern islands show no volcanic activity anymore and some are on the verge of being submerged; Genovesa is all that remains of a once massive volcano. The western islands still sit above the hot spot, so the Isabela and Fernandina volcanoes erupt frequently, and Fernandina's La Cumbre erupted in 2024.
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 The Galápagos Islands?
Volcanic activity in the Galápagos is not totally dangerous for visitors, since most tourist attractions lie far from hazardous volcanoes. The risk falls mainly on animals: some lose habitat, giant tortoises could be burned by lava or ash, and rare Galapagos pink land iguanas on Isabela's Wolf volcano could be wiped out by an eruption.
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.
Why Does The Geology Of The Galápagos Islands Matter?
Aside from its beautiful wonders, the Galápagos Islands have a unique and interesting history. Most tourists come from all over the world to see the untamed wildlife or scuba dive in the archipelago's blue waters, but fewer know how fascinating the islands' geology is. Sierra Negra is one of the volcanoes that can be visited.
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!
Planning trip to Galapagos Islands?
My wife and I spent two weeks on these magnificent islands, visited nearly every possible tour, and explored as much as we could. I shared all the important details in my comprehensive Galapagos Islands Travel Guide, where I cover everything you need to know about planning a trip to the Galapagos.
Galapagos Islands travel might surprise you with extra fees to enter the islands, the complicated logistics between islands, booking tours, and knowing which spots are free to explore and which ones are not. I’ve covered it all in this Galapagos Travel Guide.
Also, if you’re planning a trip to the Galapagos, make sure to use my link for discounted hotel prices via Booking.com. It really helps support my blog!
Questions About The Formation Of The Galápagos Islands
How were the Galapagos Islands formed?
The islands formed as the Nazca Plate moved eastward over the Galápagos hotspot, a place where magma is hotter than usual. Fluid basaltic lava built shield volcanoes, the same process that formed Hawaii. Eastern islands like San Cristóbal and Española are oldest, roughly 3 to 4 million years, while western ones like Fernandina and Isabela are youngest.
Are the Galapagos Islands volcanic?
Yes, the islands are volcanic. Eastern islands no longer have volcanic activity, while western islands such as Isabela and Fernandina still erupt. Sierra Negra on Isabela last erupted from 26 June to 23 August 2018, Wolf erupted in 2022, and Fernandina's La Cumbre in 2024.
Are the Galapagos Islands a hotspot?
Yes, the islands sit over the Galápagos hotspot, which stays in place while the Nazca Plate moves eastward over it. Geologists define a hot spot as a location where the magma is hotter than usual; the same thing created Hawaii.
