Crustal Shortening and Rheological Behavior Across the Longmen Shan Fault, Eastern Margin of the Tibetan Plateau

Knowledge of lithospheric rheology can provide fundamental insights into crustal deformation near the Longmen Shan fault (LMSF). Based on viscoelastic models constrained by interseismic geodetic observations, we obtain an optimal shortening rate 4.8 ± 0.4 mm/a across LMSF and upper mantle viscosity 5.0 × 1020?21 Pa · s beneath eastern Tibet. More importantly, find a high-viscosity zone (>1021 s) in lower crust LMSF, where steady-state is significantly higher than transient derived from postseismic deformation. Further investigations with power-law suggest that, due to stress loading Wenchuan earthquake relaxation afterwards, effective decreases ?1018 immediately after finally recovers level (?1021 s). Our results highlight stress-dependent behavior effect rheological structure during cycle.