earth science

Peru–Chile Trench

Peru–Chile Trench is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Peru–Chile Trench rather than just read about it. In short: The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about 160 kilometres (99 mi) off the coast of Peru and Chile. It reaches a maximum depth of 8,065 m (26,460 ft) below sea level in Richards Deep (23°10′45″S 71°18′41″W) and is approximately 5,900 km (3,666 mi) long; its mean width is 64 km (40 mi) and it covers an expanse of some 590,000 km2 (230,000 mi2).

Key takeaways

Peru–Chile Trench belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Peru–Chile Trench to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Peru–Chile Trench from memory before moving on to harder problems.

Reference excerpt

The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about 160 kilometres (99 mi) off the coast of Peru and Chile. It reaches a maximum depth of 8,065 m (26,460 ft) below sea level in Richards Deep (23°10′45″S 71°18′41″W) and is approximately 5,900 km (3,666 mi) long; its mean width is 64 km (40 mi) and it covers an expanse of some 590,000 km2 (230,000 mi2). The trench delineates the boundary between the 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 subducted beneath the continental South American plate. The trench is also a part of the Chile triple junction, an unusual junction that consists of a 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 2.0–2.5 kilometres (1.2–1.6 mi) of sediments, creating a flat bottom topography. Sediments are mainly turbidites interspersed with oceanic deposits of clay, volcanic ash, and siliceous ooze. The Peru–Chile Trench, the forearc and the western edge of the central Andean plateau (Altiplano), delineate the dramatic "Bolivian Orocline" that defines the Andean slope of southern Peru, northern Chile, and Bolivia.

Oceanography Most of the time, the trade winds 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. 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. In 2023, a predatory crustacean was discovered in the Atacama Trench.

Associated seismicity

The 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: Mw ~8.3 1687 Peru earthquake: Mw ~8.7 1730 Valparaíso earthquake Ms ~8.7 1746 Lima–Callao earthquake: Mw ~8.7 1868 Arica earthquake: Mw ~9.0 1877 Offshore Tarapaca, Peru: Mw ~8.3 1906 Valparaíso earthquake 1942 Peru earthquake: Mw 8.2 event associated with a tsunami, the rupture dimensions and epicenter are similar to those of a 1996 earthquake 1960 Valdivia earthquake: At Mw 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 (Ms 6.75 vs Mw 7.8) 1970 Ancash earthquake: This Mw7.9 event triggered a landslide with large snow and ice components, killing ~68,000 people 2001 southern Peru earthquake: Mw 8.4 2005 Tarapacá earthquake 2007 Tocopilla earthquake 2007 Peru earthquake: Mw 8.0 2010 Chile earthquake: Mw 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

Further reading Graham, Alan (2009-09-28). "The Andes: A Geological Overview from a Biological Perspective". Annals of the Missouri Botanical Garden. 96 (3): 371–385. doi:10.3417/2007146. ISSN 0026-6493. Mofjeld, Harold; Symons, Christina; Lonsdale, Peter; González, Frank; Titov, Vasily (2004-03-01). "Tsunami Scattering and Earthquake Faults in the Deep Pacific Ocean". Oceanography. 17 (1): 38–46. doi:10.5670/oceanog.2004.65. ISSN 1042-8275. Fisher, Robert L.; Raitt, Russell W. (1962). "Topography and structure of the Peru-Chile trench". Deep Sea Research and Oceanographic Abstracts. 9 (11–12): 423–443. doi:10.1016/0011-7471(62)90094-3. ISSN 0011-7471. Wortel, M.J.R.; Cloetingh, S.A.P.L. (1985). "Accretion and lateral variations in tectonic structure along the Peru-Chile Trench". Tectonophysics. 112 (1–4): 443–462. doi:10.1016/0040-1951(85)90190-8. hdl:1871/8418. ISSN 0040-1951.

Illustrations

Worked examples

Example 1 — a first encounter with Peru–Chile Trench

Start with the simplest possible case. Write down what Peru–Chile Trench claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Peru–Chile Trench before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Peru–Chile Trench ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Peru–Chile Trench

In research: Peru–Chile Trench appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Peru–Chile Trench in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Peru–Chile Trench is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geology of Chile, Geology of Peru, Landforms of Chile, so understanding it makes those chapters shorter.
In everyday life: Look for Peru–Chile Trench outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Peru–Chile Trench in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Peru–Chile Trench means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Peru–Chile Trench out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Peru–Chile Trench in simple terms?

Why does Peru–Chile Trench matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Peru–Chile Trench?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Peru–Chile Trench.