Tectonic Evolution of Back-Arc Basins

Back-arc basins develop behind volcanic arcs at convergent plate margins where subducting slabs roll back and induce extension in the overriding plate. Their evolution typically follows a sequence of arc‐parallel stretching, progressive crustal thinning, magmatic intrusion and, in some cases, transition to seafloor spreading. The resulting basins display a spectrum of morphologies—from narrow troughs with uneven crustal thinning to broad rift zones with incipient oceanic crust. Variations in slab geometry, convergence rate and plate coupling generate contrasting extensional regimes and fault styles along the same arc. High‐resolution seismic imaging and geophysical modelling have revealed anisotropic fabrics in the crust and upper mantle, normal and strike‐slip fault networks, and spatially variable magmatic pathways. Sedimentary systems respond to tectonic pulses, producing stacked syn‐rift units that record rift migration and post‐rift subsidence. These processes control basin architecture, hydrocarbon potential and seismic-volcanic hazard. Comparative studies of the Okinawa Trough, East China Sea Basin, Lau Basin and other back‐arc settings have highlighted the interplay between slab rollback, mantle flow and plate‐interface dynamics in shaping basin evolution globally.

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Recent ambient noise tomography in the northern Ryukyu Arc has imaged three-dimensional shear-wave velocity and anisotropic patterns in the crust and upper mantle. These results reveal arc-parallel fabrics in the upper crust driven by oblique arc retreat and arc-normal fabrics at depth attributed to corner‐flow in the mantle wedge, shedding light on the transtensional nature of back-arc rifting. A study of crustal structure and plate coupling along the Ryukyu subduction zone used P-wave velocity profiles and gravity modelling to map variations in slab buoyancy and coupling strength. It demonstrates that buoyant features such as submerged plateaus modulate coupling and influence the propensity for rift initiation. Foundational seismic surveys across the Okinawa Trough have detailed crustal thinning from 25 km to under 10 km, imaged Moho geometry and identified normal fault arrays linked to active rifting. These works collectively refine our understanding of fault evolution, magmatic intrusion and the spatial variability of extensional processes in back-arc environments.

Tectonic Evolution of Back-Arc Basins publication trend

The graph below shows the total number of articles in tectonic evolution of back-arc basins across all publications each year (not limited to Nature Index journals).

Technical terms

Back-arc basin: An extensional basin that forms on the overriding plate behind a volcanic arc in a subduction zone.

Subduction: The process by which one lithospheric plate sinks beneath another into the mantle at a convergent margin.

Rifting: Tectonic extension that leads to crustal thinning and faulting, often preceding the formation of a new oceanic basin.

Anisotropy: Directional dependence of seismic wave velocity, revealing aligned minerals or fracture fabrics in rocks.

Ambient noise tomography: A seismic imaging technique using background seismic noise to reconstruct subsurface velocity structures.

Plate coupling: The mechanical linkage across a plate interface, influencing stress transmission, seismicity and deformation patterns.

References

1. Shear‐Dominant Continental Rifting in Northern Ryukyu Revealed by Ambient Noise Tomography. Journal of Geophysical Research: Solid Earth (2024).
2. Variations in the crustal structure and strength of plate coupling along the Ryukyu subduction zone. Geoscience Letters (2023).
3. Seismic structure of rifting in the Okinawa Trough, an active backarc basin of the Ryukyu (Nansei-Shoto) island arc–trench system. Earth, Planets and Space (2019).