Juan Fernandez Island

LocationTypeTreaty CodeStatus
Juan Fernandez IslandHydroacoustic StationHA03Certified

Page 1 HA03

Thumbnail profile: Juan Fernández Islands

The Archipelago Juan Fernández was originally discovered by chance on 22 November 1574 by the Spanish sailor Juan Fernández.

The Juan Fernández Islands — of which Robinson Crusoe Island is the largest — is a sparsely inhabited island group situated in the Southern Pacific Ocean about 670 km west of the Chilean mainland. Volcanic in origin, the islands have a total area of 181 km² and a population of about 630, virtually all of whom reside in the capital, San Juan Bautista, on the north coast.  Administratively, the archipelago belongs to Chile's Region of Valparaíso, which also includes Easter Island.

The archipelago was originally discovered by chance on 22 November 1574 by the Spanish sailor Juan Fernández, who was sailing between Peru and Valparaíso and deviated from his planned course. He named the islands Más Afuera, Más a Tierra, and Islote de Santa Clara. In the 17th and 18th century it was used as a hideout for pirates and as a penal colony.

Landing at Juan Fernandez 'airport' for the pre-site survey.

These isolated islands were home to the sailor Alexander Selkirk for four years and inspired Daniel Defoe’s famous adventure novel, Robinson Crusoe, published in 1719.  This fictional autobiography was most likely influenced by the real-life events of Selkirk, a Scottish castaway who lived on the Pacific island of Más a Tierra whose name was changed to Robinson Crusoe Island in 1966, which today hosts the International Monitoring System's (IMS) infrasound station IS14.

Geology and Topography

Juan Fernandez Islands are of volcanic origin.

The volcanic origin is more than obvious in some parts of the island. Like Easter Island, the Juan Fernández Archipelago is up to four million years old. Its three islands, Robinson Crusoe, Alexander Selkirk and Santa Clara, are the only elevations of an extensive submarine ridge that is approximately 400 km long and 50 km wide.

The three islands of the archipelago rise steeply out of the Pacific, with few beaches and a limited number of protected bays, possibly formed by ancient volcanic craters.