The Peru–Chile Trench, also known as the Atacama Trench, is an

oceanic trench Oceanic trenches are prominent, long, narrow topography, topographic depression (geology), depressions of the seabed, ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers ...

in the eastern

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

, about off the coast of

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. It reaches a maximum depth of below sea level in Richards Deep () and is approximately long; its mean width is and it covers an expanse of some . The trench delineates the boundary between the

subducting Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second pla ...

Nazca plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

and the overriding

South American plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid ...

Geology

The trench is a result of a

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

, where the eastern edge of the oceanic

is being

subducted Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second plat ...

beneath the continental

. The trench is also a part of the

Chile triple junction The Chile triple junction (or Chile margin triple junction) is a geologic triple junction located on the seafloor of the Pacific Ocean off Taitao and Tres Montes Peninsula on the southern coast of Chile. Here three tectonic plates meet: the Sout ...

, an unusual junction that consists of a

mid-oceanic ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a ...

and the Chile Rise being subducted under the

at the Peru–Chile Trench. Two

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

ridges within the

enter the subduction zone along this trench: the

Nazca Ridge The Nazca Ridge is a submarine ridge, located on the Nazca plate off the west coast of South America. This plate and ridge are currently subducting under the South American plate at a convergent boundary known as the Peru-Chile Trench at approxi ...

and the

Juan Fernández Ridge The Juan Fernández Ridge is a volcanic island and seamount chain on the Nazca plate. It runs for about in a west–east direction from the Juan Fernández hotspot to the Peru–Chile Trench between the latitudes of 32-34° S before subducting ...

. From the

the trench is filled with of sediments, creating a flat bottom topography. Sediments are mainly

turbidite A turbidite is the geologic Deposition (geology), deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing ...

s interspersed with oceanic deposits of clay, volcanic ash, and siliceous ooze. The Peru–Chile Trench, the

forearc A forearc is a region in a subduction zone between an oceanic trench and the associated volcanic arc. Forearc regions are present along convergent margins and eponymously form 'in front of' the volcanic arcs that are characteristic of convergen ...

and the western edge of the central Andean plateau (Altiplano), delineate the dramatic "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 ...

" that defines the

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

slope of southern Peru, northern Chile, and

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Oceanography

Most of the time, the

trade wind The trade winds or easterlies are permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere, ...

s drive surface waters offshore near the equator, driving the

Humboldt Current The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and pro ...

from the tip of southern Chile to northern Peru. This current is associated with upwelling of deep, nutrient-rich water off the coast of Peru. At times,

El Niño EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...

disrupts the usual wind pattern and lessens the upwelling. The consequent loss of nutrient causes fish kills.

Biology

In 2018, three new species of snailfish were discovered thriving in the depths of the Atacama Trench. In 2023, a predatory crustacean was discovered in the Atacama Trench.

Associated seismicity

The

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

of the

below the

along the Chile-Peru Trench is associated with numerous earthquakes. Several of these earthquakes are notable for their size, associated tsunamis, and landslides. *1570 Concepcion earthquake: M_w ~8.3 *

1687 Peru earthquake The 1687 Peru earthquake occurred at 11:30 UTC on 20 October 1687. It had an estimated magnitude of 8.4–8.7 and caused severe damage to Lima, Callao and Ica. It triggered a tsunami and overall, about 5,000 people died. Tectonic setting The ea ...

: M_w ~8.7 *

1730 Valparaíso earthquake The 1730 Valparaíso earthquake occurred at 04:45 Time in Chile, local time (08:45 UTC) on July 8. It had an estimated Moment magnitude scale, magnitude of 9.1–9.3 and triggered a major tsunami with an estimated Tsunami#Magnitude scales, magnit ...

M_s ~8.7 *

1746 Lima–Callao earthquake The 1746 Lima–Callao earthquake occurred at on 28 October with a moment magnitude of 8.6–8.8 and a maximum Mercalli intensity of XI (''Extreme''). The epicenter was located about north-northwest of the capital Lima, which was almost comple ...

: M_w ~8.7 *

1868 Arica earthquake The 1868 Arica earthquake occurred on 13 August 1868, near Arica, then part of Peru, now part of Chile, at 21:30 UTC. It had an estimated magnitude between 8.5 and 9.3. A tsunami (or multiple tsunamis) in the Pacific Ocean was produced by th ...

: M_w ~9.0 *1877 Offshore Tarapaca, Peru: M_w ~8.3 *

1906 Valparaíso earthquake The 1906 Valparaíso earthquake hit Valparaíso, Chile, on August 16 at 19:55 local time. Its epicenter was offshore from the Valparaíso Region, and its magnitude was estimated at 8.2 . This earthquake occurred thirty minutes after the 1906 ...

1942 Peru earthquake The 1942 Peru earthquake occurred on August 24 at and was located near the border of the departments of Ica and Arequipa, Peru. It had a magnitude of 8.2 or 8.4. Earthquake This is a megathrust earthquake which ruptured part of the boundary b ...

: M_w 8.2 event associated with a tsunami, the rupture dimensions and epicenter are similar to those of a 1996 earthquake *

1960 Valdivia earthquake The 1960 Valdivia earthquake and tsunami () or the Great Chilean earthquake (''Gran terremoto de Chile'') occurred on 22 May 1960. Most studies have placed it at 9.5–9.6 on the moment magnitude scale, while some studies have placed the magnitu ...

: At M_w 9.5, the largest earthquake ever recorded on the earth *

November 1960 Peru earthquake The November 1960 Peru earthquake occurred offshore northern Peru on November 20 at . The magnitude of the earthquake was 6.75 by using the conventional surface-wave magnitude measurement within a shorter duration of ~20 s. However, there is a ...

: This event had a long source duration, leading to a significant discrepancy between different moment calculation methods ( 6.75 vs 7.8) *

1970 Ancash earthquake The 1970 Ancash earthquake (also known as the Great Peruvian earthquake) occurred on 31 May off the coast of Peru in the Pacific Ocean at . Combined with 1970 Huascarán debris avalanche, a resultant landslide, it is the most catastrophic natura ...

: This M_w7.9 event triggered a landslide with large snow and ice components, killing ~68,000 people *

2001 southern Peru earthquake The 2001 southern Peru earthquake occurred at 20:33:15 UTC (15:33:15 local time) on June 23 with a moment magnitude of 8.4 and a maximum Mercalli intensity of XII (''Extreme''). The quake affected the Peruvian regions of Arequipa, Moquegua and T ...

: M_w 8.4 * 2005 Tarapacá earthquake *

2007 Tocopilla earthquake The 2007 Tocopilla earthquake occurred on November 14 at . Its epicenter was located between Quillagua and Tocopilla, affecting the Tarapacá and the Antofagasta regions in northern Chile. The earthquake had a moment magnitude of 7.7 and lasted ...

2007 Peru earthquake The 2007 Peru earthquake, which measured 8.0 on the moment magnitude scale, hit the central coast of Peru on August 15 at 23:40:57 UTC (18:40:57 local time) and lasted two minutes. The epicenter was located south-southeast of Lima at a depth of . ...

: M_w 8.0 *

2010 Chile earthquake The 2010 Chile earthquake and tsunami () occurred off the coast of central Chile on Saturday, 27 February at 03:34:12 local time (06:34:12 UTC), having a magnitude of 8.8 on the moment magnitude scale, with intense shaking lasting for about ...

: M_w 8.8 event associated with a tsunami *

2010 Pichilemu earthquakes The 2010 Pichilemu earthquakes (), also known as the Libertador O'Higgins earthquakes, were a pair of intraplate earthquakes measuring 6.9 and 7.0 that struck Chile's O'Higgins Region on 11 March 2010 about 16 minutes apart. The earthquakes wer ...

2014 Iquique earthquake The 2014 Iquique earthquake struck off the coast of Chile on 1 April, with a moment magnitude of 8.1–8.2, at 20:46 Time in Chile, local time (23:46 Coordinated Universal Time, UTC). The epicenter of the earthquake was approximately northwest ...

* 2015 Illapel earthquake

Geology

Oceanography

Biology

Associated seismicity

See also

References

Further reading