The Nazca Plate or Nasca Plate, named after the

Nazca Nazca (; sometimes spelled Nasca; qu, Naska) is a city and system of valleys on the southern coast of Peru. It is also the name of the largest existing town in the Nazca Province. The name is derived from the Nazca culture, which flourished in ...

region of southern

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

, is an oceanic

tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

in the eastern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

basin off the west coast of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. The ongoing

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

, along the

Peru–Chile Trench The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about off the coast of Peru and Chile. It reaches a maximum depth of below sea level in Richards Deep () and is approximately long; ...

, of the Nazca Plate under the South American Plate is largely responsible for the

Andean orogeny The Andean orogeny ( es, Orogenia andina) is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system alon ...

. The Nazca Plate is bounded on the west by the

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Iza ...

and to the south by the

Antarctic Plate The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...

through the

East Pacific Rise The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located along ...

and the

Chile Rise The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca Plate and the Antarctic Plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates t ...

respectively. The movement of the Nazca Plate over several

hotspots Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tra ...

has created some

volcanic islands Geologically, a high island or volcanic island is an island of volcanic origin. The term can be used to distinguish such islands from low islands, which are formed from sedimentation or the uplifting of coral reefs (which have often formed ...

as well as east-west running

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

chains that subduct under

. Nazca is a relatively young plate both in terms of the age of its rocks and its existence as an independent plate having been formed from the break-up of the

Farallon Plate The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west ...

about 23 million years ago. The oldest rocks of the plate are about 50 million years old.

Boundaries

East Pacific and Chile Rise

triple junction A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can ...

, the Chile Triple Junction, occurs on the seafloor of the

off Taitao and

Tres Montes Peninsula The Tres Montes Peninsula ( es, Península Tres Montes, English: ''Three Hills Peninsula'') is a southwestward projection of Taitao Peninsula which in turn connects to the mainland of Chile by the narrow Isthmus of Ofqui. The peninsula is situat ...

at the southern coast of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. Here, three

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...

plates meet: the Nazca Plate, the South American Plate, and the

Peru–Chile Trench

The eastern margin is a

convergent boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more Plate tectonics, lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can ...

subduction zone under the South American Plate and the

Andes Mountains The Andes, Andes Mountains or Andean Mountains (; ) are the List of mountain ranges#Mountain ranges by length, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range i ...

, forming the

. The southern side is a

divergent boundary In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent b ...

with the Antarctic Plate, the

, where

seafloor spreading Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener an ...

permits

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

to rise. The western side is a divergent boundary with the

, forming the

. The northern side is a divergent boundary with the

Cocos Plate The Cocos Plate is a young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate ...

, the

Galapagos Rise The Galapagos Rise is a divergent boundary located between the South American coast and the triple junction of the Nazca Plate, the Cocos Plate, and the Pacific Plate. The volcanically active Galapagos Islands exist on the Galápagos hotspot ...

. The subduction of the Nazca plate under southern Chile has a history of producing massive

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...

s, including the largest ever recorded on earth, the

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

9.5 1960 Valdivia earthquake.

Intraplate features

Hotspots

A second triple junction occurs at the northwest corner of the plate where the Nazca, Cocos, and Pacific Plates all join off the coast of

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. Yet another triple junction occurs at the southwest corner at the intersection of the Nazca, Pacific, and Antarctic Plates off the coast of southern

. 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 Microplate and lies just west of

Easter Island Easter Island ( rap, Rapa Nui; es, Isla de Pascua) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is most famous for its nearl ...

Aseismic ridges

The Carnegie Ridge is a and up to feature on the ocean floor of the northern Nazca Plate that includes the Galápagos archipelago at its western end. It is being subducted under South America with the rest of the Nazca Plate.

Fracture zones

The

Darwin Gap Darwin may refer to: Common meanings * Charles Darwin (1809–1882), English naturalist and writer, best known as the originator of the theory of biological evolution by natural selection * Darwin, Northern Territory, a territorial capital city i ...

is the area between the Nazca Plate and the coast of

, where

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

experienced the earthquake of 1835. It is expected that this area will be the

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

of a major quake in the near future.

Plate motion

The absolute motion of the Nazca Plate has been calibrated at east motion (88°), one of the fastest absolute motions of any tectonic plate. The subducting Nazca Plate, which exhibits unusual

flat slab subduction Flat slab subduction is characterized by a low subduction angle (<30 degrees to horizontal) beyond the

seismogenic layer

, is tearing as well as deforming as it is subducted (Barzangi and Isacks). The subduction has formed, and continues to form, the

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

Mountain Range. Deformation of the Nazca Plate even affects the

geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

, far to the east (Tinker et al.). The

1994 Bolivia earthquake The 1994 Bolivia earthquake occurred on June 9, 1994. The epicenter was located in a sparsely populated region in the Amazon jungle, about 200 miles from La Paz. The Harvard CMT Project assigned it a focal depth of 647 km and a magnitude ...

occurred on the Nazca Plate; this had a magnitude of 8.2

M_w

, which at that time was the strongest instrumentally recorded earthquake occurring deeper than . Aside from the

Juan Fernández Islands The Juan Fernández Islands ( es, Archipiélago Juan Fernández) are a sparsely inhabited series of islands in the South Pacific Ocean reliant on tourism and fishing. Situated off the coast of Chile, they are composed of three main volcanic i ...

, this area has very few other islands that are affected by the earthquakes that are a result of complicated movements at these junctions.

Geologic history

The precursor of the Nazca Plate, Juan de Fuca Plate, and the

was the

, which split in the late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

, about 22.8 Mya, a date arrived at by interpreting

magnetic anomalies In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying ...

. Subduction under the South American continent began about 140 Mya, although the formation of the high parts of the Central Andes and the Bolivian

orocline An orocline — from the Greek words for "mountain" and "to bend" — is a bend or curvature of an orogenic (mountain building) belt imposed after it was formed. The term was introduced by S. Warren Carey in 1955 in a paper setting forth how comp ...

did not occur until 45 Mya. It has been suggested that the mountains were forced up by the subduction of the older and heavier parts of the plate, which sank more quickly into the mantle.

References

Bibliography

Extreme Science site: "A Lesson in Plate tectonics"
The basics explained.

*Muawia Barazangi and Bryan L. Isacks, "Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America" in ''Geology'' Vol. 4, No. 11, pp. 686–692
Abstract
*Mark Andrew Tinker, Terry C. Wallace, Susan L. Beck, Stephen Myers, and Andrew Papanikolas, "Geometry and state of stress of the Nazca plate beneath Bolivia and its implication for the evolution of the Bolivian orocline" in ''Geology'' 24(5), pp. 387–39
Abstract
*Cahill, T. and B. Isacks (1992). "Seismicity and shape of the subducted Nazca plate." ''Journal Geophysical Research'' 97 (12) *James, D. (1978). "Subduction of the Nazca plate beneath Central Peru." ''Geology'' 6 (3) pp 174–178
Martin Meschede and Udo Barckhausen, "Plate tectonic evolution of the Cocos-Nazca spreading center"
{{Authority control Tectonic plates Geology of Chile Natural history of Oceania Natural history of South America Geology of the Pacific Ocean