Strike-Slip Fault Damage Zones in the Anadarko Basin, Oklahoma, USA

In this chapter, we expand these analyses to the subsurface by investigating the damage-zone structure of a 32-km (~105 ft) long right-lateral strike-slip fault in Oklahoma. We used the 3D seismic attribute of coherence to first define its regional and background levels, and then evaluated the damage-zone dimensions at multiple sites. We found damage-zone thickness of ~1615 m 1600 m (5300 ft) at a segment that is dominated by subsidiary faults, and it is slightly thicker at a segment with a pull-apart basin. The damage-zone intensity decays exponentially with distance from the fault core, in agreement with field observations and distribution of seismic events. The coherence map displays a strong asymmetry of the damage-zone between the two sides of the 3D fault, which is related to the subsidiary structures of the fault-zone. We also suggest that the damage zone contains a high density of subseismic fractures associated with multiscale faulting and secondary folding that may correspond to highly permeable features within the Woodford Shale.