Triple Junction - Examples

Examples

• The junction of the Red Sea, the Gulf of Aden and the East African Rift centered in the Afar Triangle is an example of a triple junction (the Afar Triple Junction). This is the only Ridge-Ridge-Ridge (R-R-R) triple junction above sea level.
• Another example of a triple junction is the junction between the Arabian Plate, the African Plate, and the Indo-Australian Plate.
• Another active example is the Galapagos Triple Junction, an R-R-R triple junction where the Nazca, the Cocos, and the Pacific Plates meet. The East Pacific Rise extends north and south from this junction and the Galapagos Rise goes to the east. This example is made more complex by the Galapagos Microplate which is a small separate plate on the rise just to the southeast of the triple junction.
• Further north on the west coast of North America another unstable triple junction is to be found offshore of Cape Mendocino. There the San Andreas Fault, a strike-slip fault and transform plate boundary, approaches from the south. The San Andreas Fault separates the Pacific Plate and the North American Plate. To the north lies the Cascadia subduction zone, where the section of the Juan de Fuca Plate called the Gorda Plate is being subducted under the margin of the North American Plate at a plate boundary called a trench (T). Another transform fault runs along the boundary between the Pacific Plate and the Gorda Plate called the Mendocino Fault (F). Where the three intersect is a seismically active F-F-T triple junction called the Mendocino Triple Junction.
• The Amurian Plate, the Okhotsk Plate, and the Philippine Sea Plate is another triple junction where Mt. Fuji is.
• The North Sea is located at an old triple junction of three former continental plates of the Palaeozoic era: Avalonia, Laurentia and Baltica.