The Online Encyclopedia and Dictionary






Nazca Plate

The Nazca plate is shown in light blue on this map
The Nazca plate is shown in light blue on this map

The Nazca Plate is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The eastern margin is a convergent boundary subduction zone under the South American Plate and the Andes Mountains forming the Peru-Chile Trench.

The southern side is a divergent boundary, the Chile Rise , with the Antarctic Plate. The western side is a divergent boundary with the Pacific Plate forming the East Pacific Rise. The northern side is a divergent boundary, the Galapagos Rise, with the Cocos Plate. A triple junction occurs at the northwest corner of the plate where the Nazca, the Cocos, and the Pacific plates join. A second triple junction occurs at the southwest corner at the intersection with the Nazca, the Pacific, and the Antarctic plates. At each of these triple junctions an anomalous microplate exists, the Galapagos Microplate at the northern junction and the Juan Fernandez Microplate at the southern junction. The Easter Island Microplate is a third microplate that is located just north of the Juan Fernandez and lies just west of Easter Island.

Another triple junction occurs where the Nazca, Antarctic and South American plates meet. This triple junction has been considered to be related to the moment magnitude 9.5, 1960 megathrust earthquake known as the Great Chilean Earthquake.

The subducting Nazca Plate has formed, and continues to form the volcanic Andes Mountain Range.

The Nazca Plate is named for the ancient Nazca people of South America, the plate's easterly border.


Last updated: 05-07-2005 06:08:17
Last updated: 05-13-2005 07:56:04