How Long Can the Postseismic and Interseismic Phases of Great Subduction Earthquake Sustain? Toward an Integrated Earthquake‐Cycle Perspective

Abstract

AbstractThe transition of subduction systems from postseismic to interseismic phase is an important indicator of their stress state and readiness for subsequent events. However, understanding the dynamics of this transition of megathrust earthquakes is hindered by the short instrumental time compared to the centuries‐long recurrence interval (T). Here, with an updated earthquake‐cycle perspective of global spatiotemporally limited geodetic observations, we use generic viscoelastic earthquake‐cycle models to explore the evolution of time‐varying surface deformation. Self‐consistently, our models reproduce key observed features of the deformation cycle, suggesting common processes activated at different margins. The relative postseismic and interseismic durations are found dependent mainly nonlinearly on the ratio ofTto mantle viscosity, with a plausible range of ∼0.2–0.4Tat representative margins and minimum >0.55T, respectively. Our results thus provide a useful tool for understanding the similarities and differences of earthquake‐cycle deformation and guiding monitoring of possible future signals at world‐wide subduction zones.