Earth Observations taken by the Expedition 21 Crew

ISS021-E-011833 (22 Oct. 2009) --- The southern Savage Islands in the Atlantic Ocean are featured in this image photographed by an Expedition 21 crew member on the International Space Station. The Savage Islands, or Ilhas Selvagens in Portuguese, comprise a small archipelago in the eastern North Atlantic Ocean between the archipelago of Madeira to the north and the Canary Islands to the south. Like other island groups, the Savage Islands are thought to have been produced by volcanism related to a mantle plume or ?hot spot?. Mantle plumes are relatively fixed regions of upwelling magma that can feed volcanoes on an overlying tectonic plate. Active volcanoes form over the plume, and become dormant as they are carried away on the moving tectonic plate. Scientists believe that over geologic time, this creates a line of older extinct volcanoes, seamounts, and islands extending from the leading active volcanoes that are currently over the plume. This view illustrates the smaller and more irregularly-shaped Ilheus do Norte, Ilheu de Fora, and Selvagem Pequena. Spain and Portugal both claim sovereignty over the Savage Islands. All of the islands of the archipelago are ringed by bright white breaking waves along the fringing beaches. Coral reefs that surround the Savage Islands make it very difficult to land boats there, and there is no permanent settlement on the islands.