Integrated geophysical study for subsurface characterization of basement in the Cherokee platform, northeastern Oklahoma

The aim of the study is to create a more accurate map of basement faults in Cherokee Platform, northeastern Oklahoma, which will provide an improved understanding of seismic hazard in the region. Aeromagnetic data is processed and interpreted in conjunction with basement penetrating well logs. Preliminary interpretation of aeromagnetic anomalies suggests a relation to faulted structures in the basement. The Cherokee Platform province of Oklahoma is characterized by steep faults (Powers, 1931) which are associated with Proterozoic and Phanerozoic tectonics (Sims et al., 2005). According to USGS, Oklahoma has experienced an increase of magnitude 3.0 and greater earthquakes from 1-2 per year between 1978 and 2008, to 890 in 2015. The aeromagnetic data in Oklahoma is ubiquitous in the form of a magnetic anomaly map provided by USGS. We calculated horizontal gradient magnitude, total gradient amplitude and vertical derivative for the magnetic anomaly grid. Preliminary interpretation of maps generated from these methods provide a good correlation with the basement faults in the region. Depth and curvature analysis on the magnetic anomaly grid are used to locate sources of magnetic anomaly and estimate their depth and strike. Our ultimate goal is to generate an enhanced map of basement faults in the northeastern Oklahoma region which is plagued by the recent increase in seismicity induced by waste water injection. We believe, these methods along with well data will provide accurate location and extent of faults which is important for seismic hazard assessment.