Physics-Based Approach to Deep Interseismic Creep: Implications for North Tabriz Fault Behavior Using MCMC

Abstract

Many studies assume that the distribution of a fault slip rate remains constant with time when examining surface deformation. However, recent numerical simulations have shown that dynamic rupture can penetrate regions with increased friction and diffuse from the lock-to-creep transition, contradicting this assumption. Bruhat and Segall (2017) introduced a new method to account for the downward penetration of interseismic slip into the locked zone. This study builds upon their work by applying their model to strike-slip fault environments and incorporating creep coupling to viscoelastic flow in the lower crust and upper mantle. In this study, using Bruhat’s (2020) model, the interseismic deformation rates on the North Tabriz Fault are investigated. This study utilizes elastic and viscoelastic probabilistic models to fit horizontal surface rates. By employing this updated approach, a physics-based solution for deep interseismic creep is developed, revealing potential slow vertical propagation. The improved fit of horizontal deformation rates on the North Tabriz Fault is examined, leading to reasonable estimations of earthquake rupture depth and seismic displacement. The best-fit solutions suggest a half-space relaxation time of approximately 156 years, with a diffusion rate of less than 1 m/year and around 0.419 m/year, indicating minimal creep diffusion.

Keywords

• creep and deformation
• fault slip rate
• interseismic slip
• MCMC
• North Tabriz Fault