A Theory of Inter‐Granular Transient Dislocation Creep: Implications for the Geophysical Studies on Mantle Rheology

Transient creep may play an important role in short-term (small strain) time-dependent deformation such as the post-glacial rebound and post-seismic deformation. Among various mechanisms of transient creep, I focus on inter-granular dislocation caused by plastic anisotropy each grain. The essence this process is evolution strain accommodation across grain-boundaries from elastic to (viscous) accommodation. Extending previous studies, show that leads two asymptotic behaviors: at small strain, strength controlled largely soft slip system. In contrast, when exceeds a threshold value, occurs mostly hard model predicts order (depending also degree anisotropy) contrast between steady-state depends crystal. Consequently, plays these processes. Since systems have different properties, applications rheological properties inferred long-term geodynamic processes needs be made with great care.