Characterization of Damage Zone Associated with Strike-slip Faults and its Multiscale Statistics

De Joussineau, Ghislain¹, Atilla Aydin¹ (1) Stanford University, Stanford, CA

We document the formation and evolution of the damage zone associated with strike-slip faults in the Jurassic Aztec Sandstone of the Valley of Fire (SE Nevada) through detailed field and statistical study of faults with increasing slip magnitude. The origin and evolution of the damage zone are closely related to the history of fault development, as shown in a new conceptual model for damage zone evolution with fault growth. This model illustrates the critical role of fault segmentation and linkage of the adjacent hierarchical segments in controlling the geometrical and statistical properties of the evolving damage zones and secondary faults.

The statistical properties of the fault networks are determined through scanline surveys in which we distinguish between the different structural elements and determine the characteristics of each element. There is a systematic evolution in the statistical properties of damage zones with fault growth attributed to the progressive saturation of fault networks. Well-developed fault networks have multifractal properties with important consequences on the forecasting of frequency and spacing characteristics of faults from limited data sets. The conceptual model proposed here together with the statistical data may be used as predictive tools to better estimate the geometrical and statistical properties of damage zones associated with large faults with resolvable slip magnitude detectable in the subsurface seismic data, with important consequences for fluid flow.