We document the formation and evolution of the damage zones associated with strike‐slip faults in porous sandstone, through detailed field and statistical studies of faults of increasing slip magnitudes. The faults initiate as sheared joints with discontinuous damage zone located primarily at fault tips and fault surface irregularities. With increasing slip, the damage zone develops by progressive fracture infilling and is organized into two components with different characteristics. The first of these components is the inner damage zone flanking the fault core with a high fracture frequency and a thickness scaling with fault slip. It contributes to the progressive widening of the fault core with increasing deformation. The second of these components is the outer damage zone with a larger and more variable thickness and a lower fracture frequency than the inner zone. The origin and evolution of the inner and outer damage zones are closely related to the history of fault development, as presented in a new conceptual model for damage zone evolution with fault growth. The statistical properties of the fault networks, determined by scan line surveys, evolve with fault growth. This is attributed to the progressive saturation of the fault networks. Well‐developed fault networks have multifractal properties with important consequences in forecasting and characterizing faults from limited data sets. The conceptual model and statistical data presented here may be used as predictive tools to better estimate the geometrical and statistical properties of the damage zones associated with large faults with remotely resolvable slip magnitude in the subsurface.

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Fault segmentation and fault steps and their evolution are relevant to the dynamics and size of earthquake ruptures, the distribution of fault damage zones and the capacity of fault seal. Furthermore, segment interactions and coalescence are the fundamental processes for fault growth. To contribute to this end, we investigated the architecture of strike-slip faults by combining field observations in the Valley of Fire State Park, Nevada, and the published data sets.First, we studied the trace complexity for 49 faults with offsets ranging from 12 m to 460 km. We established that the number of fault steps (hence fault segments) per unit length is correlated to the maximum fault offset by a negative power law. The faults have longer segments and fewer steps when their offsets increase, indicating the progressive growth, smoothening and simplification of the fault traces as a function of the offset, as proposed by previous investigators.Second, we studied the dimensions of the segments and steps composing *20 of the previous fault systems. The mean segment length, mean step length and mean step width are all correlated to the maximum fault offset by positive power laws over four orders of magnitude of the offset. In addition, the segment length distributions of four of the faults with offsets ranging from 80 m to 100 km are all lognormal, with most of the segment lengths falling in the range of one to five times the maximum offset of the faults. Finally, the fault steps have an approximately constant length-to-width ratio indicating that, regardless of their environment, strike-slip faults have a remarkable self-similar architecture probably due to the mechanical processes responsible for fault growth. Our data sets can be used as tools to better predict the geometrical attributes of strike-slip fault systems with important consequences for earthquake ruptures, the distribution and properties of fault damage zones, and fault sealing potential.