Plate data: Bird (2003), PB2002, converted by Hugo Ahlenius, Nordpil (ODC-By 1.0). Land: Natural Earth (India POV).
The Nazca Plate is an oceanic plate in the southeast Pacific, off the west coast of South America. Its eastern edge is the Peru-Chile trench, where it sinks under the South American Plate. USGS notes that the plate as a whole sinks smoothly, but the deepest part breaks into pieces that stay locked for long periods and then slip in large earthquakes.
Its western edge is the East Pacific Rise, a spreading ridge. Near Easter Island, about 3,400 km west of Chile, the East Pacific Rise has the fastest spreading rate USGS lists: more than 15 cm per year. PB2002 places Easter Island and the Galapagos Islands on the Nazca Plate.1 USGS adds that Easter Island, famous for stone monoliths carved by ancient Polynesians out of volcanic rock, is moving east toward South America at the fastest seafloor spreading rate known in the world (USGS).
The ridge on its western edge is not a single clean line. Bird (2003) adds three microplates along the East Pacific Rise. The Easter Plate, about 550 by 410 km, lies in a fork of the rise between 22 and 27 degrees south. It was named for Easter Island but does not include it; Bird notes that the island now sits on the Nazca Plate. The Juan Fernandez Plate, about 410 by 270 km, lies in another fork between 32 and 35 degrees south, named for islands 2,800 km to the east. At the northern corner, Lonsdale (1988) found a microplate about 120 km wide where a simple triple junction of the Pacific, Cocos and Nazca Plates had been expected, and named it Galapagos after the nearest land.
Bird describes these microplates as plates of 100 to 500 km that appear in the middle of an ocean spreading system and rotate rapidly relative to their neighbors (Bird 2003).
Nazca Plate in numbers
Measured from its PB2002 outline, the Nazca Plate covers about 16.1 million km², or 3.2% of the
Earth's surface. That makes it number 9 by area of the 52 plates in the model.
It spans from 46°S to 7°N and from 114°W to 71°W.
Its edge is about 20,154 km long, mostly divergent:
37.8%divergentDivergent boundary. Plates pull away from each other and new crust forms between them. Source (7,611 km)
, 35.7%convergentConvergent boundary. Plates move toward each other and crust is destroyed as one plate dives under another. Source (7,205 km)
and 26.5%transformTransform boundary. Plates slide horizontally past each other. Crust is neither made nor destroyed. Source (5,338 km)
.
Along its boundaries it moves a mean 7.9 cm/yr relative to its neighbors, fastest against the Pacific Plate. Bird (2003)
Neighboring plates Neighbors. Plates that share a boundary with this plate. Most plate movement happens along these narrow zones between plates. Source
The Nazca Plate shares a boundary with 10 plates in PB2002, longest shared edge first.
The longest, about 4,433 km, is with the Pacific Plate; the shortest, about 282 km, is with the Galapagos Plate.
Placed by point-in-polygon test on the PB2002 plate outlines (Bird 2003). USGS and Bird both place Easter Island on the Nazca Plate; neither states the plate of the Galapagos Islands.
Nazca Plate FAQ
How big is the Nazca Plate?
About 16.1 million km², or 3.2% of the Earth's surface, measured from its PB2002 outline. It ranks 9 of 52 plates by area.
Which plates border the Nazca Plate?
10 plates: Pacific Plate, South American Plate, Antarctic Plate, Cocos Plate, North Andes Plate, Altiplano Plate, Easter Plate, Juan Fernandez Plate, Panama Plate and Galapagos Plate.
What kind of plate boundaries does the Nazca Plate have?
Mostly divergent boundaries. 37.8% divergent, 35.7% convergent, 26.5% transform, of 20,154 km in total.
How fast does the Nazca Plate move?
Relative to its neighbors, a mean 79.2 mm/yr (7.9 cm/yr) along its boundaries in PB2002. The fastest boundary is with the Pacific Plate.
