Transient Creep in Subduction Zones by Long‐Range Dislocation Interactions in Olivine

Large earthquakes transfer stress from the shallow lithosphere to underlying viscoelastic lower crust and upper mantle, inducing transient creep during postseismic interval. Recent experiments on olivine have provided a new rheological model for this based accumulation release of back stresses among dislocations. Here, we test whether natural rocks preserve dislocation-induced heterogeneity consistent with back-stress hypothesis by mapping palaeosubduction interface Oman-UAE ophiolite high-angular resolution electron backscatter diffraction. The preserves heterogeneous residual that vary in magnitude several hundred megapascals over length scales few micrometers. are commonly spatially associated elevated densities geometrically necessary dislocations within subgrain interiors. These spatial relationships, along characteristic probability distributions stresses, confirm is generated records their long-range elastic interactions. Images decorated oxidation display bands high low dislocation density, suggesting interactions contributed organization substructure. results support applicability deformation mantle portion plate-boundary shear zones. predicts rapid changes, such as those imposed large earthquakes, can induce order-of-magnitude changes viscosity depend nonlinearly change, inferences rheology geodetic observations.