Oceanic trench

trenchtrenchesocean trenchoceanic trenchessubmarine trenchdeep-sea trenchdeep sea trenchocean trenchesrollbackSlab rollback
Oceanic trenches are topographic depressions of the sea floor, relatively narrow in width, but very long.wikipedia
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Plate tectonics

tectonic platesplate tectonictectonic
Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few millimeters to over ten centimeters per year.
Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries (or faults).

Island arc

island arcsarcisland-arc
Trenches are generally parallel to a volcanic island arc, and about 200 km from a volcanic arc.
They also possess a distinct curved form, a chain of active or recently extinct volcanoes, a deep-sea trench, and a large negative Bouguer anomaly on the convex side of the volcanic arc. The small positive gravity anomaly associated with volcanic arcs has been interpreted by many authors as due to the presence of dense volcanic rocks beneath the arc. While inactive arcs are a chain of islands which contains older volcanic and volcaniclastic rocks.

Volcanic arc

magmatic arcarc volcanismarc
Trenches are generally parallel to a volcanic island arc, and about 200 km from a volcanic arc. The overriding plate typically contains a volcanic arc and forearc region.
Generally, volcanic arcs result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench.

Challenger Deep

Challenger Deep, Earthdeepest dive in the Pacificdeepest known point
The greatest ocean depth measured is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m below sea level.
It is a relatively small slot-shaped depression in the bottom of a considerably larger crescent-shaped oceanic trench, which itself is an unusually deep feature in the ocean floor.

Mariana Trench

Marianas TrenchMarianadeepest known
The greatest ocean depth measured is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m below sea level.
The Mariana Trench or Marianas Trench is located in the western Pacific Ocean about 200 km east of the Mariana Islands; it is the deepest trench in the world.


subduction zonesubductedsubducting
A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab.
They start to go down at oceanic trenches.

Outer trench swell

outer riseouter-rise
As the subducting plate approaches the trench, it first bends upwards to form the outer trench swell, then descends to form the outer trench slope.
The outer trench swell, outer trench high, or outer rise is a subtle ridge on the seafloor near an oceanic trench, where a descending plate begins to flex and fault in preparation for its descent into the mantle at a subduction zone.


forearc basinfore-arcfore-arc basin
The overriding plate typically contains a volcanic arc and forearc region.
A forearc is the region between an oceanic trench and the associated volcanic arc.

Aleutian Trench

AleutianAlaska-Aleutian MegathrustAleutian subduction zone
A similar relationship between proximity to rivers, forearc width, and trench morphology can be observed from east to west along the Alaskan-Aleutian convergent margin.
The Aleutian Trench (or Aleutian Trough) is an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian islands.

Puerto Rico Trench

Puerto Rican Trenchthe bottom of the Atlantic Ocean
Further north, far from major sediment sources, the Puerto Rico Trench is over 8600 m deep and there is no active accretionary prism.
The oceanic trench is associated with a complex transition between the Lesser Antilles subduction zone to the south and the major transform fault zone or plate boundary, which extends west between Cuba and Hispaniola through the Cayman Trough to the coast of Central America.


HimalayaHimalayanHimalayan Mountains
Trenches are related to but distinguished from continental collision zones (such as that between India and Asia forming the Himalaya), where continental crust enters a subduction zone.
Since both plates were composed of low density continental crust, they were thrust faulted and folded into mountain ranges rather than subducting into the mantle along an oceanic trench.

John Murray (oceanographer)

Sir John MurrayJohn MurrayDr John Murray
The term “trench” does not appear in Murray and Hjort's (1912) classic oceanography book.
He was the first to note the existence of the Mid-Atlantic Ridge and of oceanic trenches.

Accretionary wedge

accretionary prismaccretionary complexaccretion
The forearc consists of igneous and metamorphic crust, and this crust may act as buttress to a growing accretionary wedge (formed from sediments scraped off the top of the downgoing plate).
A series of thrusts verging towards the trench are formed with the youngest most outboard structures progressively uplifting the older more inboard thrusts.

Felix Andries Vening Meinesz

F.A. Vening MeineszDr. Felix Vening MeineszFelix A. Vening Meinesz
During the 1920s and 1930s, Felix Andries Vening Meinesz developed a unique gravimeter that could measure gravity aboard a submarine and used it to measure gravity over trenches.
An important result was the discovery of elongated belts of negative gravity anomalies along the oceanic trenches.

Turbidity current

turbiditicturbidity currentsturbidity flow
Sediment transport is controlled by submarine landslides, debris flows, turbidity currents, and contourites.
Turbidity currents can sometimes result from submarine seismic instability, which is common with steep underwater slopes, and especially with submarine trench slopes of convergent plate margins, continental slopes and submarine canyons of passive margins.

Tonga Trench

TongaHorizon Deep
The Tonga Trench is an oceanic trench located in the south-west Pacific Ocean.

Philippine Trench

East Luzon TrenchPhilippine DeepMindanao Deep
The Philippine Trench (also Philippine Deep, Mindanao Trench, and Mindanao Deep) is a submarine trench to the east of the Philippines.

Kermadec Trench

Kermadec subduction zoneKermadec-Tonga subduction zoneKermadec
The Kermadec Trench is a linear ocean trench in the south Pacific Ocean.

Japan Trench

Japanese Trench
The Japan Trench is an oceanic trench part of the Pacific Ring of Fire off northeast Japan.

Back-arc basin

back-arcback-arc spreadingback-arc extension
This is called trench rollback or hinge retreat (also hinge rollback) and is one explanation for the existence of back-arc basins.
Most of them result from tensional forces caused by oceanic trench rollback (the oceanic trench is wandering in the seafloor direction) and the collapse of the edge of the continent.

Kuril–Kamchatka Trench

Kuril-Kamchatka TrenchKuril TrenchKuril-Kamchatka
The Kuril–Kamchatka Trench or Kuril Trench (Курило-Камчатский жёлоб, Kurilo-Kamchatskii Zhyolob) is an oceanic trench in the northwest Pacific Ocean.

Peru–Chile Trench

Peru-Chile TrenchAtacama TrenchChile Trench
Thick accumulations of turbidites along a trench can be supplied by down-axis transport of sediments that enter the trench 1000 – away, as is found for the Peru–Chile Trench south of Valparaíso and for the Aleutian Trench.
The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about 160 kilometres (100 mi) off the coast of Peru and Chile.

Izu-Ogasawara Trench

Izu-Bonin TrenchBonin TrenchIzu-Bonin
The Izu-Ogasawara Trench, also known as Izu-Bonin Trench, is an oceanic trench in the western Pacific Ocean, consisting of the Izu Trench (at the north) and the Bonin Trench (at the south, west of the Ogasawara Plateau).

South Sandwich Trench

Meteor Deeptrench
The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying 100 km to the east of the South Sandwich Islands.

Hikurangi Trench

Hikurangi TroughHikurangi Subduction ZoneHikurangi Subduction System
The Hikurangi Trench, also called the Hikurangi Trough, is an oceanic trench in the bed of the Pacific Ocean off the east coast of the North Island of New Zealand, lying between the southern end of the Cook Strait and the Chatham Rise.