Characterization of strike-slip fault–splay relationships in sandstone

We document the length and angular relationships between strike-slip faults and their splays. The data indicate that the maximum splay length is correlated to the fault length by a power law but shows little correlation with the fault slip magnitude. The kink angle between faults and their splays is small for isolated faults (average ∼20°) and systematically larger for mechanically interacting faults (average ∼50°). Analytical models predict that splay length decreases with increasing confinement under biaxial compression. 2D numerical models of isolated faults show that small kink angles correspond to small values of the angle between the fault and the maximum compression (β) whereas large kink angles require greater β values. Similar models of interacting faults confirm the critical role of β on the kink angles and suggest that fault overlap and fault separation can also induce important variations in the kink angles. Our results provide a basis for a better understanding of fault segment linkage via splaying process and for a better assessment of the maximum thickness of fault damage zones. The results may also help to predict the length and orientation of secondary faults formed by splaying associated with first order faults with resolvable slip magnitude in the subsurface.