About the Islands

Ecuador annexed the Galápagos Islands on 12 February 1832.

The Galápagos Islands (official name: Archipiélago de Colón, Spanish),  is one of the 24 Provinces that are part of the Republic of Ecuador, are an archipelago of volcanic islands distributed on either side of the equator in the Pacific Ocean surrounding the centre of the Western Hemisphere.

Located 906 km (563 mi) west of continental Ecuador, the islands are known for their large number of endemic species that were studied by Charles Darwin during the second voyage of HMS Beagle. His observations and collections contributed to the inception of Darwin’s theory of evolution by means of natural selection.

The Galápagos Islands and their surrounding waters form the Galápagos Province of Ecuador, the Galápagos National Park, and the Galápagos Marine Reserve.

The islands have a population of slightly over 35,000 citizens,the first recorded visit to the islands happened by chance in 1535, when Fray Tomás de Berlanga, the Bishop of Panamá, was surprised with this undiscovered land during a voyage to Peru to arbitrate in a dispute between Francisco Pizarro and Diego de Almagro.

The newly independent Republic of Ecuador took the islands from Spanish ownership in 1832, and subsequently gave them official Spanish names. The older names remained in use in English-language publications.

Volcanism has been continuous on the Galápagos Islands for at least 20 million years, and perhaps even longer. The mantle plume beneath the east-ward moving Nazca Plate (51 km/myr) has given rise to a 3-kilometre-thick platform under the island chain and seamounts. Besides the Galápagos Archipelago, other key tectonic features in the region include the Northern Galápagos Volcanic Province between the archipelago and the Galápagos Spreading Center (GSC) 200 km to the north at the boundary of the Nazca Plate and the Cocos Plate. This spreading center truncates into the East Pacific Rise on the west and is bounded by the Cocos Ridge and Carnegie Ridge in the east. Furthermore, the Galápagos Hotspot is at the northern boundary of the Pacific Large Low Shear Velocity Province while the Easter Hotspot is on the southern boundary.

The Galápagos Archipelago is characterized by numerous contemporaneous volcanoes, some with plume magma sources, others from the asthenosphere, possibly due to the young and thin oceanic crust. The GSC caused structural weaknesses in this thin lithosphere leading to eruptions forming the Galápagos Platform.

Fernandina and Isabela in particular are aligned along these weaknesses. Lacking a well-defined rift zone, the islands have a high rate of inflation prior to eruption. Sierra Negra on Isabela Island experienced a 240 cm uplift between 1992 and 1998, most recent eruption in 2005, while Fernandina on Fernandina Island indicated an uplift of 90 cm, most recent eruption in 2009. Alcedo on Isabela Island had an uplift of greater than 90 cm, most recent eruption in 1993.

Additional characteristics of the Galápagos Archipelago are closer volcano spacing, smaller volcano sizes, and larger calderas. For instance, Isabela Island includes 6 major volcanoes, Ecuador, Wolf, Darwin, Alcedo, Sierra Negra and Cerro Azul, with most recent eruptions ranging from 1813 to 2008. The neighboring islands of Santiago and Fernandina last erupted in 1906 and 2020, respectively. Overall, the 9 active volcanoes in the archipelago have erupted 26 times between 1961 and 2011. The shape of these volcanoes is that of an “overturned soup bowl” as opposed to the “overturned saucer plate” of the Hawaiian Islands. The Galápagos’s shape is due to the pattern of radial and circumferential fissure, radial on the flanks, but circumferential near the caldera summits. It is the circumferential fissures which give rise to stacks of short lava flows.

The volcanoes at the west end of the archipelago are in general, taller, younger, have well developed calderas, and are mostly composed of tholeiitic basalt, while those on the east are shorter, older, lack calderas, and have a more diverse composition.
The ages of the islands, from west to east are 0.05 Ma for Fernandina, 0.65 Ma for Isabela, 1.10 Ma for Santiago, 1.7 Ma for Santa Cruz, 2.90 Ma for Santa Fe, and 3.2 Ma for San Cristobal. The calderas on Sierra Negra and Alcedo have active fault systems.
The Sierra Negra fault is associated with a sill 2 km below the caldera. The caldera on Fernandina experienced the largest basaltic volcano collapse in history, with the 1968 phreatomagmatic eruption. Fernandina has also been the most active volcano since 1790, with recent eruptions in 1991, 1995, 2005, 2009 and 2020 and the entire surface has been covered in numerous flows since 4.3 Ka. The western volcanoes have numerous tuff cones.

The islands are located at the Galapagos Triple Junction. The archipelago is located on the Nazca Plate (a tectonic plate), which is moving east/southeast, diving under the South American Plate at a rate of about 2.5 inches (6.4 cm) per year. It is also atop the Galápagos hotspot, a place where the Earth’s crust is being melted from below by a mantle plume, creating volcanoes. The first islands formed here at least 8 million and possibly up to 90 million years ago.

While the older islands have disappeared below the sea as they moved away from the mantle plume, the youngest islands, Isabela and Fernandina, are still being formed. In April 2009, lava from the volcanic island Fernandina started flowing both towards the island’s shoreline and into the center caldera.

In late June 2018, Sierra Negra, one of five volcanoes on Isabela and one of the most active in the Galápagos archipelago, began erupting for the first time since 2005. Lava flows made their way to the coastline, prompting the evacuation of about fifty nearby residents and restricting tourist access.

Main Islands.-
Baltra (South Seymour) Island – Baltra is a small flat island located near the centre of the Galápagos. It was created by geological uplift. The island is very arid, and vegetation consists of salt bushes, prickly pear cacti and palo santo trees. Until 1986, ⦁ Baltra (Seymour) Airport was the only airport serving the Galápagos. Now, there are two airports which receive flights from the continent; the other is located on ⦁ San Cristóbal Island. Private planes flying to Galápagos must fly to Baltra, as it is the only airport with facilities for planes overnight. On arriving in Baltra, all visitors are immediately transported by bus to one of two docks. The first dock is located in a small bay, where the boats cruising Galápagos await passengers. The second is a ferry dock, which connects Baltra to the island of Santa Cruz. During the 1940s, scientists decided to move 70 of Baltra’s ⦁ land iguanas to the neighboring ⦁ North Seymour Island as part of an experiment. This move proved unexpectedly useful when the native iguanas became extinct on Baltra as a result of the island’s military occupation in ⦁ World War II. During the 1980s, iguanas from North Seymour were brought to the ⦁ Charles Darwin Research Station as part of a breeding and repopulation project, and in the 1990s, land iguanas were reintroduced to Baltra. As of 1997, scientists counted 97 iguanas living on Baltra; 13 of which had hatched on the islands.

⦁ Bartolomé (Bartholomew) Island – Bartolomé Island is a volcanic islet just off the east coast of Santiago Island in the Galápagos Islands group. it is one of the “younger” islands in the Galápagos archipelago. This island, and neighbouring Sulivan Bay on Santiago (James) island, are named after lifelong friend of Charles Darwin, ⦁ Sir Bartholomew James Sulivan, who was a lieutenant aboard ⦁ HMS ⦁ Beagle.⦁ [1] Today Sulivan Bay is often misspelled Sullivan Bay. This island is one of the few that are home to the ⦁ Galápagos penguin which is the only wild penguin species to live on the equator. The ⦁ green turtle is another animal that resides on the island.

⦁ Darwin (Culpepper) Island – This island is named after Charles Darwin. It has an area of 1.1 km2 (0.42 sq mi) and a maximum altitude of 168 metres (551 ft). Here fur seals, frigates, ⦁ marine iguanas, swallow-tailed gulls, sea lions, whales, marine turtles, and red-footed and Nazca boobies can be seen.

⦁ Española (Hood) Island – Its name was given in honor of Spain. It also is known as Hood, after ⦁ Viscount Samuel Hood. It has an area of 60 km2 (23 sq mi) and a maximum altitude of 206 metres (676 ft). Española is the oldest island at around 3.5 million years, and the southernmost in the group. Due to its remote location, Española has a large number of endemic species. It has its own species of lava lizard, mockingbird, and ⦁ Galápagos tortoise. Española’s ⦁ marine iguanas exhibit a distinctive red coloration change between the breeding season. Española is the only place where the ⦁ waved albatross nests. Some of the birds have attempted to breed on ⦁ Genovesa (Tower) Island, but unsuccessfully. Española’s steep cliffs serve as the perfect runways for these birds, which take off for their ocean feeding grounds near the mainland of Ecuador and Peru. Española has two visitor sites. Gardner Bay is a swimming and snorkelling site, and offers a great beach. Punta Suarez has migrant, resident, and endemic wildlife, including brightly colored ⦁ marine iguanas, Española lava lizards, ⦁ hood mockingbirds, ⦁ swallow-tailed gulls, ⦁ blue-footed boobies, ⦁ Nazca boobies, ⦁ red-billed tropicbirds, Galápagos hawks, three species of Darwin’s finches, and the waved albatross.

Fernandina (Narborough) Island – The name was given in honor of King ⦁ Ferdinand II of Aragon, who sponsored the voyage of Columbus. Fernandina has an area of 642 km2 (248 sq mi) and a maximum altitude of 1,494 m (4,902 ft). This is the youngest and westernmost island. On 13 May 2005, a new, very eruptive process began on this island, when an ash and water vapor cloud rose to a height of 7 km (23,000 ft) and lava flows descended the slopes of the volcano on the way to the sea. Punta Espinosa is a narrow stretch of land where hundreds of marine iguanas gather, largely on black lava rocks. The famous ⦁ flightless cormorants inhabit this island, as do ⦁ Galápagos penguins, ⦁ pelicans, ⦁ Galápagos sea lions and ⦁ Galápagos fur seals. Different types of ⦁ lava flows can be compared, and the ⦁ mangrove forests can be observed.

⦁ Floreana (Charles or Santa María) Island – It was named after ⦁ Juan José Flores, the first ⦁ President of Ecuador, during whose administration the government of Ecuador took possession of the archipelago. It is also called Santa Maria, after ⦁ one of the caravels of Columbus. It has an area of 173 km2 (67 sq mi) and a maximum elevation of 640 m (2,100 ft). It is one of the islands with the most interesting human history, and one of the earliest to be inhabited. ⦁ Flamingos and green sea turtles nest (December to May) on this island. The patapegada or ⦁ Galápagos petrel, a sea bird which spends most of its life away from land, is found here. At Post Office Bay, where 19th-century ⦁ whalers kept a ⦁ wooden barrel that served as a post office, mail could be picked up and delivered to its destinations, mainly Europe and the United States, by ships on their way home. At the “Devil’s Crown”, an underwater ⦁ volcanic cone and ⦁ coral formations are found.

⦁ Genovesa (Tower) Island – The name is derived from ⦁ Genoa, Italy, the birthplace of Christopher Columbus. It has an area of 14 km2 (5.4 sq mi) and a maximum altitude of 76 m (249 ft). This island is formed by the remaining edge of a large ⦁ caldera that is submerged. Its nickname of “the bird island” is clearly justified. At Darwin Bay, ⦁ frigatebirds and ⦁ swallow-tailed gulls, the only nocturnal species of gull in the world, can be seen. Red-footed ⦁ boobies, noddy ⦁ terns, lava gulls, tropic birds, ⦁ doves, ⦁ storm petrels and ⦁ Darwin finches are also in sight. Prince Philip’s Steps is a bird-watching ⦁ plateau with Nazca and red-footed boobies. There is a large Palo Santo forest.

⦁ Isabela (Albemarle) Island – This island was named in honor of ⦁ Queen Isabella I of Castile.⦁ [2] With an area of 4,640 km2 (1,790 sq mi), it is the largest island of the Galápagos. Its highest point is Volcán Wolf, with an altitude of 1,707 m (5,600 ft). The island’s ⦁ seahorse shape is the product of the merging of six large volcanoes into a single land mass. On this island, Galápagos penguins, flightless cormorants, marine iguanas, pelicans and ⦁ Sally Lightfoot crabs abound. At the skirts and calderas of the volcanoes of Isabela, land iguanas and Galápagos tortoises can be observed, as well as Darwin finches, Galápagos hawks, Galápagos doves and very interesting lowland vegetation. The third-largest human settlement of the archipelago, ⦁ Puerto Villamil, is located at the southeastern tip of the island.
North Seymour Island in the Galápagos; Daphne Island is in the distance.
Marchena (Bindloe) Island – Named after Fray Antonio Marchena, it has an area of 130 km2 (50 sq mi) and a maximum altitude of 343 m (1,125 ft). ⦁ Galapagos hawks and sea lions inhabit this island, and it is home to the ⦁ Marchena lava lizard, an endemic animal.

⦁ North Seymour Island – Its name was given after an English nobleman, ⦁ Lord Hugh Seymour. It has an area of 1.9 km2 (0.73 sq mi) and a maximum altitude of 28 m (92 ft). This island is home to a large population of blue-footed boobies and swallow-tailed gulls. It hosts one of the largest populations of frigate birds. It was formed from geological uplift.

⦁ Pinzón (Duncan) Island – Named after the Pinzón brothers, captains of the Pinta and Niña caravels, it has an area of 18 km2 (6.9 sq mi) and a maximum altitude of 458 m (1,503 ft).

⦁ Pinta (Louis) Island – Named after the Pinta caravel, it has an area of 60 km2 (23 sq mi) and a maximum altitude of 777 m (2,549 ft). Sea lions, Galápagos hawks, giant tortoises, marine iguanas, and dolphins can be seen here. Pinta Island was home to the last remaining Pinta tortoise, called ⦁ Lonesome George. He was moved from Pinta Island to the ⦁ Charles Darwin Research Station on Santa Cruz Island, where scientists attempted to breed from him. However, Lonesome George died in June 2012 without producing any offspring.

⦁ Rábida (Jervis) Island – It bears the name of the convent of Rábida, where Columbus left his son during his voyage to the Americas. It has an area of 4.95 km2 (1.91 sq mi) and a maximum altitude of 367 m (1,204 ft). The high amount of iron contained in the lava at Rábida gives it a distinctive red colour. White-cheeked pintail ducks live in a saltwater lagoon close to the beach, where brown pelicans and boobies have built their nests. Until recently, flamingos were also found in the lagoon, but they have since moved on to other islands, likely due to a lack of food on Rábida. Nine species of finches have been reported in this island.

San Cristóbal (Chatham) Island – It bears the name of the patron saint of seafarers, “⦁ St. Christopher”. Its English name was given after ⦁ William Pitt, 1st Earl of Chatham. It has an area of 558 km2 (215 sq mi) and its highest point rises to 730 m (2,400 ft). This is the first island in the Galápagos Archipelago Charles Darwin visited during his voyage on the Beagle. This islands hosts ⦁ frigate birds, sea lions, giant tortoises, blue- and red-footed ⦁ boobies, tropicbirds, ⦁ marine iguanas, dolphins and ⦁ swallow-tailed gulls. Its vegetation includes Calandrinia galapagos, Lecocarpus darwinii, and trees such as Lignum vitae. The largest freshwater lake in the archipelago, Laguna El Junco, is located in the ⦁ highlands of San Cristóbal. The capital of the ⦁ province of Galápagos is ⦁ Puerto Baquerizo Moreno, which lies at the southern tip of the island, and is close to ⦁ San Cristóbal Airport.

From an aircraft flying out of Baltra Island (on the right) and the Santa Cruz (on the left), the Itabaca Channel is the waterway between the islands.

Santa Cruz (Indefatigable) Island – Given the name of the Holy Cross in Spanish. It was originally named Norfolk Island by Cowley, but renamed after the British frigate ⦁ HMS ⦁ Indefatigable after her visit there in 1812.⦁ [3] It has an area of 986 km2 (381 sq mi) and a maximum altitude of 864.5 m (2,836 ft). Santa Cruz hosts the largest human population in the archipelago, the town of ⦁ Puerto Ayora. The ⦁ Charles Darwin Research Station and the headquarters of the Galápagos National Park Service are located here. The GNPS and CDRS operate a tortoise breeding centre here, where young tortoises are hatched, reared, and prepared to be reintroduced to their natural ⦁ habitat. The Highlands of Santa Cruz offer exuberant flora, and are famous for the lava tunnels. Large tortoise populations are found here. Black Turtle Cove is a site surrounded by mangroves, which sea turtles, rays and small sharks sometimes use as a mating area. Cerro Dragón, known for its flamingo lagoon, is also located here, and along the trail one may see land iguanas foraging.

⦁ Santa Fe (Barrington) Island – Named after a city in Spain, it has an area of 24 km2 (9.3 sq mi) and a maximum altitude of 259 m (850 ft). Santa Fe hosts a forest of ⦁ Opuntia ⦁ cactus, which are the largest of the archipelago, and Palo Santo. Weathered cliffs provide a haven for swallow-tailed gulls, red-billed tropic birds and ⦁ shearwater petrels. ⦁ Santa Fe species of ⦁ land iguanas are often seen, as well as ⦁ lava lizards.

⦁ Santiago (San Salvador, James) Island – Its name is equivalent to Saint James in English; it is also known as San Salvador, after the first island discovered by Columbus in the Caribbean Sea. This island has an area of 585 km2 (226 sq mi) and a maximum altitude of 907 m (2,976 ft). Marine iguanas, sea lions, fur seals, land and sea turtles, ⦁ flamingos, dolphins and sharks are found here. Pigs and goats, which were introduced by humans to the islands and have caused great harm to the endemic species, have been eradicated (pigs by 2002; goats by the end of 2006). ⦁ Darwin finches and Galápagos hawks are usually seen, as well as a colony of fur seals. At Sulivan Bay, a recent (around 100 years ago) pahoehoe ⦁ lava flow can be observed.

⦁ Wolf (Wenman) Island – This island was named after the German geologist ⦁ Theodor Wolf. It has an area of 1.3 km2 (0.50 sq mi) and a maximum altitude of 253 m (830 ft). Here, ⦁ fur seals, frigatebirds, Nazca and red-footed boobies, marine iguanas, sharks, whales, dolphins and swallow-tailed gulls can be seen. The most famous resident is the ⦁ vampire finch, which feeds partly on blood pecked from other birds, and is only found on this island.

⦁ Minor Islands.-

⦁ Daphne Major – A small island directly north of Santa Cruz and directly west of Baltra, this very inaccessible island appears, though unnamed, on Ambrose Cowley’s 1684 chart. It is important as the location of multidecade finch population studies by ⦁ Peter and Rosemary Grant.

⦁ South Plaza Island (Plaza Sur) – It is named in honor of a former president of Ecuador, General ⦁ Leónidas Plaza. It has an area of 0.13 km2 (0.050 sq mi) and a maximum altitude of 23 m (75 ft). The flora of South Plaza includes ⦁ Opuntia cactus and ⦁ Sesuvium plants, which form a reddish carpet on top of the lava formations. Iguanas (land, marine and some hybrids of both species) are abundant, and large numbers of birds can be observed from the cliffs at the southern part of the island, including tropic birds and swallow-tailed gulls.

⦁ Nameless Island – A small islet used mostly for ⦁ scuba diving.

⦁ Roca Redonda – An islet approximately 25 km (16 mi) northwest of ⦁ Isabela. Herman Melville devotes the third and fourth sketches of ⦁ The Encantadas to describing this islet (which he calls “Rock Rodondo”) and the view from it.