Subduction Zones: A Short Review

Schellart, Wouter P.

doi:10.1016/b978-0-323-85733-8.00009-3

Cited by 4 publications

(3 citation statements)

References 274 publications

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“…For example, previous subduction models (and data from subduction zones in nature) have shown that the SP velocity increases with increasing slab width (Schellart et al., 2010). The OP also contributes to the subduction rate, with a global average trench‐normal velocity of 0.81 cm/yr (Schellart, 2023). However, most narrow subduction zones, which are the focus of this work, are embedded within much larger and relatively immobile plates, with the subducting and OPs usually having low trench‐normal velocities.…”

Section: Discussionmentioning

confidence: 99%

Overriding Plate Thickness as a Controlling Factor for Trench Retreat Rates in Narrow Subduction Zones

Gea,

Mancilla,

Negredo

et al. 2024

Geochem Geophys Geosyst

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Slab width is a significant factor in controlling subduction zone dynamics, particularly the retreat velocities, which tend to decrease with wider slabs. However, observations of natural narrow subduction zones reveal no correlation between slab width and trench velocities. This suggests that other factors may exert a greater influence. In this study, we employ 3D numerical subduction models to systematically assess the impact of slab width, strength of slab coupling to the lateral plate (LP), and overriding plate (OP) thickness on trench kinematics and geometry. Our models focus on narrow slabs (400–1,200 km), and the results demonstrate that, in the case of narrow subduction zones, the slab width has little effect on trench migration rates and the viscous coupling at the lateral slab edge is only important for very narrow subduction zones (≤800 km). Conversely, the OP thickness emerges as a crucial factor, with increasing plate thickness leading to a strong decrease in trench velocities. These findings provide an explanation for the observed trench velocities in natural narrow subduction zones, where an inverse relationship with OP thickness is evident. Furthermore, our study reveals that not only slab width, but also the OP thickness and the slab coupling to the LP, significantly influence trench geometry. Strong lateral coupling promotes the formation of concave trench geometries, while thick overriding plates favor the development of “w”‐shaped geometries. Overall, a comprehensive understanding of subduction processes necessitates considering the interplay between slab width, OP thickness, and slab coupling to the LP.

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Section: Discussionmentioning

confidence: 99%

Overriding Plate Thickness as a Controlling Factor for Trench Retreat Rates in Narrow Subduction Zones

Gea,

Mancilla,

Negredo

et al. 2024

Geochem Geophys Geosyst

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“…This study investigates upper mantle subduction, focusing mainly on processes whereby the slab stagnates above the 660 km discontinuity with variable kinematic conditions along its strike. Schellart (2023) lists 28 active subduction zones, of which the bigger ones have been subdivided into segments, resulting in a total of 46 subduction zone segments. Combining the study of Schellart (2023) and the slab depth extent investigations as presented in Schellart et al.…”

Section: Introductionmentioning

confidence: 99%

“…Schellart (2023) lists 28 active subduction zones, of which the bigger ones have been subdivided into segments, resulting in a total of 46 subduction zone segments. Combining the study of Schellart (2023) and the slab depth extent investigations as presented in Schellart et al. (2008) indicates that from these 46 segments, 20 have not reached the 660 km discontinuity yet, while 26 have, and for those that have, 10 are deflected horizontally (at least partly) at the 660 km discontinuity, while the remaining 16 either end at the discontinuity or go through it relatively unperturbed.…”

Section: Introductionmentioning

confidence: 99%

Effects of Along‐Trench Asymmetric Subduction Initiation on Plate Rotation and Trench Migration: A Laboratory Modeling Perspective

Wang,

Ding,

Schellart

et al. 2024

Tectonics

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The impact of along‐trench asymmetric subduction on plate kinematic evolution (e.g., plate rotation and trench migration) remains enigmatic. In this study, analog experiments were performed to investigate the effects of symmetric and asymmetric subduction initiation on slab kinematics and trench migration. In cases when subduction was started with a cylindric slab perturbation, the plate showed little rotation during the entire subduction process, resulting in a trench shape that was symmetric with respect to the center‐line of the plate. However, if subduction started with a non‐cylindrical slab perturbation, the trench shape changed substantially. During the free sinking stage, the more deeply subducted part of the slab had a higher trench‐normal retreat velocity (VT⊥) and subduction velocity (VS⊥) than the shallow part, which induced trench and plate rotations in the same direction. This along‐trench gradient in VT⊥ increased until the deeper portion of the slab tip first touched the bottom, after which a marked decrease in VS⊥ occurred at this location; the other side of the slab had not yet reached the bottom, so experienced no recorded reduction of subduction velocity at this time. This along‐strike diachronous arrival of the slab tip could induce a marked along‐strike reversal in magnitude of the subduction velocity and a rotation torque centered on the point of first contact between slab and 660‐km discontinuity. This could lead to instability and rotation of the subducting slab, potentially causing a reversal in the direction of trench rotation direction, but rarely in the direction of plate rotation. Our modeling results may provide useful understanding for the processes driving the rotations of the trench and plate in natural subduction zones.

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Synthesis of the Seismic Structure of the Greater Alaska Region: Geodynamics Implications

Jadamec,

Pavlis,

Yang

et al. 2024

Geophysical Monograph Series

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Subduction Zones: A Short Review

Cited by 4 publications

References 274 publications

Overriding Plate Thickness as a Controlling Factor for Trench Retreat Rates in Narrow Subduction Zones

Overriding Plate Thickness as a Controlling Factor for Trench Retreat Rates in Narrow Subduction Zones

Effects of Along‐Trench Asymmetric Subduction Initiation on Plate Rotation and Trench Migration: A Laboratory Modeling Perspective

Synthesis of the Seismic Structure of the Greater Alaska Region: Geodynamics Implications

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