Mid-mantle discontinuities beneath subduction zones linked to depth-dependent deformation of bridgmanite.

Seismic discontinuities near 1000 km depth beneath subduction zones are linked to deformation-induced anisotropy in bridgmanite, with a 1.5% shear wave velocity contrast.

• Why it matters: Understanding the origin of mid-mantle reflectors is crucial for interpreting mantle dynamics and the structure of Earth's interior, which remains poorly explained by existing models.
• What they did: The study combines thermo-mechanical subduction simulations with pressure-dependent fabric calculations in bridgmanite, revealing depth-dependent slip transitions that produce detectable seismic anisotropy.
• The result: The findings suggest that strain-induced mid-mantle reflectors are a plausible mechanism connecting mantle flow, mineral physics, and seismic observations, enhancing interpretation of subduction zone structures.