Back-arc region
title: "Back-arc region" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["plate-tectonics", "subduction"] topic_path: "general/plate-tectonics" source: "https://en.wikipedia.org/wiki/Back-arc_region" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/ce/Subduction-en.svg" caption="A back-arc above a subduction zone"] ::
The back-arc region is the area behind a volcanic arc. In island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs. In continental arcs, the back-arc region is part of the continental platform, either dry land (subaerial) or forming shallow marine basins.
Formation
Back-arc deformation is a product of subduction at convergent plate tectonic boundaries. It initiates and evolves behind the volcanic arc on the overriding plate of a subduction zone.{{Citation | last = Heuret, A. | first = Lallemand, S. | title = Plate motions, slab dynamics and back-arc deformation | journal = Physics of the Earth and Planetary Interiors | volume = 149 | issue = 1–2 | pages = 31–51 | date = March 2005 | doi = 10.1016/j.pepi.2004.08.022 | bibcode = 2005PEPI..149...31H | last = Uyeda | first = S. | title = Subduction zones: An introduction to comparative subductology | journal = Tectonophysics | volume = 81 | issue = 3–4 | pages = 133–159 | date = January 1982 | doi = 10.1016/0040-1951(82)90126-3 | bibcode = 1982Tectp..81..133U
Back-arcs can form on either oceanic crust or continental crust. In the case of oceanic crust, most back-arc regions are subjected to tensional stresses and thus develop a spreading center where new oceanic crust is formed.{{Citation | last = Taylor, B. | first = Martinez, F. | title = Back-arc basin basalt systematics | journal = Earth and Planetary Science Letters | volume = 210 | issue = 3–4 | pages = 481–497 | date = May 2003 | doi = 10.1016/S0012-821X(03)00167-5 | bibcode = 2003E&PSL.210..481T | citeseerx = 10.1.1.486.4485
Back-arc extension vs. compression
The back-arc deformation may be either extensional or compressional. The overriding plate will shorten when its motion is directed towards the trench, resulting in a compression of the back-arc region.{{Citation | last = Heuret | first = A. | last2 = Funiciello | first2 = F. | last3 = Faccenna | first3 = C. | last4 = Lallemand | first4 = S. | title = Plate kinematics, slab shape and back-arc stress: A comparison between laboratory models and current subduction zones | journal = Earth and Planetary Science Letters | volume = 256 | issue = 3–4 | pages = 473–483 | date = April 2007 | doi = 10.1016/j.epsl.2007.02.004 | bibcode = 2007E&PSL.256..473H
The extreme cases of these two types of back-arc deformation can be found in Chile and at the Marianas arc. The shallow dipping slab subducting beneath Chile at an angle of about 10–15° causes a compressional stress on the back-arc region behind the Andes.{{Citation | last = Uyeda |first= S. | last2= Kanamori | first2 = H. | authorlink2 = Hiroo Kanamori | title = Back-arc opening and the mode of subduction | journal = Journal of Geophysical Research: Solid Earth | volume = 84 | issue = B3 | pages = 1049–1061 | date = March 1979 | doi = 10.1029/JB084iB03p01049 |bibcode= 1979JGR....84.1049U |url= https://authors.library.caltech.edu/58814/1/Uyeda_1979-JGR.pdf
References
References
- Moores, Eldridge M.. (1995). "Tectonics". [[W. H. Freeman and Company]].
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