DEM Modelling-Based Insights into the Controlling Factors of Strike-Slip Fault Segmentation

Strike-slip shearing is widespread in the brittle crust and is typically expressed as segmented rupture zones with characteristic spacing. Yet, the key factors controlling this geometric pattern remain poorly understood. In this study, we use discrete element method (DEM) simulations to systematically explore the fundamental physical and tectonic controls on fault segment spacing in strike-slip systems. Our results show that spacing is influenced by both physical and tectonic factors. Physically, spacing increases with crustal thickness and strength, but decreases with density and gravitational acceleration. A near-linear relationship emerges between the ratio of spacing length to thickness and the ratio of strength to the combined effects of density, gravity, and thickness. Tectonically, spacing is reduced by increasing thrust components but enlarged by extensional components. Pre-existing weak zones strongly localize rupture, while surface topography modulates rupture propagation, with segments preferentially forming in lower-elevation areas. These results offer new insights into the mechanics of segmented strike-slip ruptures on Earth and other planetary bodies and provide a framework for better assessing natural hazard risks.