The Midland Basin is experiencing elevated rates of seismicity linked to oil-field wastewater disposal. Until recently, our understanding of subsurface faulting was limited to the basin margins, with earthquake sequences evolving in regions of unknown deformation. To understand the causal factors of earthquakes and assess the evolving hazard, we present a regional fault interpretation and fault slip hazard assessment in the form of fault slip potential (FSP).

We map and analyze 795 basement-rooted faults, expressed as high-angle reverse and near-vertical strike-slip faults. High-angle reverse faults that strike north-northwest–south-southeast define the eastern margin of the Central Basin platform and generate the greatest structural relief. East of the Central Basin platform, north-northwest–south-southeast– and north-northeast–south-southwest–striking reverse faults bound low-amplitude uplifts. Reverse faults are accompanied by west-northwest–east-southeast– and west-southwest–east-northeast–striking strike-slip faults, which limit the lateral length of reverse faults and associated uplifts, coinciding with a reversal in fault-bounded uplift vergence direction, and exhibit evidence for transpressional translation. These observations suggest that reverse structures initiated during late Paleozoic orogenesis, but west-northwest–east-southeast– and west-southwest–east-northeast–striking strike-slip faults are the late Paleozoic reactivation of a long-standing Proterozoic fabric.

Earthquakes have occurred on basement-rooted high-angle reverse and reverse–strike-slip faults, which are reactivated under present-day stress conditions as normal and normal–strike-slip, respectively. The FSP analyses show that west-northwest–east-southeast– and west-southwest–east-northeast–striking faults are sensitive to reactivation under modest pore pressure increase. Our results provide a foundation to investigate causal behavior and characterize fault slip hazard and can therefore be used to plan and regulate ongoing petroleum operations.