View source for Peru–Chile Trench

{{Short description|Oceanic trench in the Pacific Ocean off South America}}
{{more citations needed|date=September 2014}}
[[Image:Peru-Chile trench.jpg|thumb|200px|{{legend|#02105B|Peru–Chile Trench}}]]

The '''Peru–Chile Trench''', also known as the '''Atacama Trench''', is an [[oceanic trench]] in the eastern [[Pacific Ocean]], about {{convert|160.|km}} off the coast of [[Peru]] and [[Chile]].<ref name=Britannica>{{cite encyclopedia|title=Peru-Chile Trench|url=http://www.britannica.com/EBchecked/topic/453259/Peru-Chile-Trench|encyclopedia=Encyclopædia Britannica|access-date=April 21, 2014}}</ref> It reaches a maximum depth of {{Convert|8065|m|ft|abbr=on}} below sea level in Richards Deep ({{Coord|23|10|45|S|71|18|41|W|display=inline}}) and is approximately {{Convert|5900.|km|mi|abbr=on}} long; its mean width is {{Convert|64|km|mi|abbr=on}} and it covers an expanse of some {{Convert|590000|km2|mi2|abbr=on}}.

The trench delineates the boundary between the [[subduction|subducting]] [[Nazca plate]] and the overriding [[South American plate]].

==Geology==
The trench is a result of a [[convergent plate boundary]], where the eastern edge of the oceanic [[Nazca plate]] is being [[subduction|subducted]] beneath the continental [[South American plate]].<ref name=Britannica /> The trench is also a part of the [[Chile triple junction]], an unusual junction that consists of a [[Mid-ocean ridge|mid-oceanic ridge]] and the [[Chile Rise]] being subducted under the [[South American plate]] at the Peru–Chile Trench. Two [[seamount]] ridges within the [[Nazca plate]] enter the subduction zone along this trench: the [[Nazca Ridge]] and the [[Juan Fernández Ridge]].

From the [[Chile triple junction]] to [[Juan Fernández Ridge]] the trench is filled with {{convert|2.0|–|2.5|km}} of sediments, creating a flat bottom topography. Sediments are mainly [[turbidite]]s interspersed with oceanic deposits of clay, volcanic ash, and siliceous ooze.<ref name=Britannica />

The Peru–Chile Trench, the [[forearc]] and the western edge of the central Andean plateau (Altiplano), delineate the dramatic "Bolivian [[Orocline]]" that defines the [[Andes|Andean]] slope of southern Peru, northern Chile, and [[Bolivia]].

==Oceanography==
Most of the time, the [[trade wind]]s drive surface waters offshore near the equator, driving the [[Humboldt Current]] 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.<ref name=Oceana>{{cite web|title=Peru-Chile Trench|url=http://oceana.org/en/explore/marine-places/peru-chile-trench|work=Oceana|access-date=April 21, 2014|url-status=dead|archive-url=https://web.archive.org/web/20140825094639/http://oceana.org/en/explore/marine-places/peru-chile-trench|archive-date=August 25, 2014}}</ref> At times, [[El Niño]] 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.<ref>Wang, Amy, ''Scientists discover three new sea creatures in depths of the Pacific Ocean'', The Washington Post, Wednesday, September 12, 2018</ref><ref>{{cite web|url=https://www.theguardian.com/environment/2018/sep/15/gel-like-see-through-fish-discovered-75km-down-on-pacific-ocean-floor|title='Gel-like' see-through fish discovered 7.5&nbsp;km down on Pacific ocean floor|work=The Guardian|date=2018-09-15}}</ref>

In 2023, a [[Dulcibella camanchaca|predatory crustacean]] was discovered in the Atacama Trench.<ref>{{Cite web |last=Dixit |first=Mrigakshi |title=Atacama Trench's terrifying new resident survives at 25,900 feet |url=https://interestingengineering.com/science/atacama-trenchs-new-resident-at-25900-feet |access-date=2024-12-23 |website=Interesting Engineering |language=en}}</ref>

==Associated seismicity==
[[File:USGS AmSo 0120170002fig1.png|thumb|'''Significant Earthquake''' Faults and damaging earthquakes over the past century along the South American Subduction Zone<ref name=USGS20180314>USGS [https://www.usgs.gov/news/usgs-authors-new-report-seismic-hazard-risk-and-design-south-america USGS Authors New Report on Seismic Hazard, Risk, and Design for South America]</ref>]]
[[File:USGS AmSo 0120170002fig11a.png|thumb|South America showing 100-year earthquake shaking projections.<ref name=USGS20180314/>]]
The [[Subduction zone|subduction]] of the [[Nazca plate]] below the [[South American plate]] 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: [[Moment magnitude scale|M<sub>w</sub>]] ~8.3
*[[1687 Peru earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] ~8.7
*[[1730 Valparaíso earthquake]] [[Surface wave magnitude|M<sub>s</sub>]] ~8.7
*[[1746 Lima–Callao earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] ~8.7
*[[1868 Arica earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] ~9.0
*1877 Offshore Tarapaca, Peru:<ref name=USGS>{{cite web|title=Historic World Earthquakes: Chile|url=https://earthquake.usgs.gov/earthquakes/world/historical_country.php#chile|publisher=United States Geological Survey|url-status=dead|archive-url=https://web.archive.org/web/20100728221758/http://earthquake.usgs.gov/earthquakes/world/historical_country.php#chile|archive-date=2010-07-28}}</ref> [[Moment magnitude scale|M<sub>w</sub>]] ~8.3
*[[1906 Valparaíso earthquake]]
*[[1942 Peru earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] 8.2 event associated with a tsunami, the rupture dimensions and epicenter are similar to those of a 1996 earthquake
*[[1960 Valdivia earthquake]]: At [[Moment magnitude scale|M<sub>w</sub>]] 9.5, the largest earthquake ever recorded on the earth
*[[November 1960 Peru earthquake]]: This event had a long source duration, leading to a significant discrepancy between different moment calculation methods ({{M|s|link=y}} 6.75 vs {{M|w|link=y}} 7.8) 
*[[1970 Ancash earthquake]]: This [[Moment magnitude scale|M<sub>w</sub>]]7.9 event triggered a landslide with large snow and ice components, killing ~68,000 people
*[[2001 southern Peru earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] 8.4
*[[2005 Tarapacá earthquake]]
*[[2007 Tocopilla earthquake]]
*[[2007 Peru earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] 8.0
*[[2010 Chile earthquake]]: [[Moment magnitude scale|M<sub>w</sub>]] 8.8 event associated with a tsunami
*[[2010 Pichilemu earthquakes]]
*[[2014 Iquique earthquake]]
*[[2015 Illapel earthquake]]

== See also ==
*[[Oceanic trench]]
*Pacific [[Ring of Fire]]

==References==
{{reflist}}

==Further reading==
*{{Cite journal |last=Graham |first=Alan |date=2009-09-28 |title=The Andes: A Geological Overview from a Biological Perspective |url=http://dx.doi.org/10.3417/2007146 |journal=Annals of the Missouri Botanical Garden |volume=96 |issue=3 |pages=371–385 |doi=10.3417/2007146 |issn=0026-6493|url-access=subscription }}
*{{Cite journal |last1=Mofjeld |first1=Harold |last2=Symons |first2=Christina |last3=Lonsdale |first3=Peter |last4=González |first4=Frank |last5=Titov |first5=Vasily |date=2004-03-01 |title=Tsunami Scattering and Earthquake Faults in the Deep Pacific Ocean |url=http://dx.doi.org/10.5670/oceanog.2004.65 |journal=Oceanography |volume=17 |issue=1 |pages=38–46 |doi=10.5670/oceanog.2004.65 |issn=1042-8275|doi-access=free }}
*{{Cite journal|last1=Fisher |first1=Robert L. |last2=Raitt |first2=Russell W. |date=1962|title=Topography and structure of the Peru-Chile trench |url=http://dx.doi.org/10.1016/0011-7471(62)90094-3 |journal=Deep Sea Research and Oceanographic Abstracts |volume=9 |issue=11–12 |pages=423–443 |doi=10.1016/0011-7471(62)90094-3 |issn=0011-7471|url-access=subscription }}
*{{Cite journal |last1=Wortel |first1=M.J.R. |last2=Cloetingh |first2=S.A.P.L. |date=1985 |title=Accretion and lateral variations in tectonic structure along the Peru-Chile Trench |url=http://dx.doi.org/10.1016/0040-1951(85)90190-8 |journal=Tectonophysics |volume=112 |issue=1–4 |pages=443–462 |doi=10.1016/0040-1951(85)90190-8 |issn=0040-1951|hdl=1871/8418 |hdl-access=free }}
{{geology of Chile}}
{{2010 Chile earthquake}}

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{{DEFAULTSORT:Peru-Chile Trench}}
[[Category:Geology of Chile]]
[[Category:Geology of Peru]]
[[Category:Landforms of Chile]]
[[Category:Landforms of Peru]]
[[Category:Lowest points of the World Ocean]]
[[Category:Natural history of South America]]
[[Category:Oceanic trenches of the Pacific Ocean]]
[[Category:Subduction zones]]