Geologic Provinces of Oklahoma

Northcutt, Robert A.; Campbell, Jock A.

doi:10.1007/978-94-011-5098-9_2

Cited by 12 publications

(10 citation statements)

References 4 publications

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“…Phanerozoic sedimentary rock covers the crystalline basement throughout Oklahoma except in the southern part of the state where the basement has been tectonically uplifted. Key tectonic events affecting the sedimentary rocks and the basement include the late Paleozoic Ouachita and Alleghenian orogenies, which contributed variations in basement relief of over 10 km in southern Oklahoma (e.g., Crain & Chang, 2018;Johnson, 2008;Northcutt & Campbell, 1995). There is pronounced structural grain in this area with mostly WNW faults in southwestern Oklahoma and ENE faults in southeastern Oklahoma (Marsh & Holland, 2016).…”

Section: Geologic Backgroundmentioning

confidence: 99%

Aeromagnetic Data Reveal Potential Seismogenic Basement Faults in the Induced Seismicity Setting of Oklahoma

Shah

Crain

2018

Geophysical Research Letters

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New aeromagnetic survey data collected over north central Oklahoma image possible seismogenic faults in the crystalline basement. Linear earthquake sequences associated with induced seismicity suggest the reactivation of ancient basement faults, but few of these sequences are aligned with mapped faults. The new data show many earthquake sequences aligned with linear magnetic gradients or offsets between anomalies, while mapped faults, which mainly describe sedimentary cover, show limited correspondence with either. This strongly suggests significant structural differences between the crystalline basement and sedimentary cover. Furthermore, while the earthquakes are occurring on reactivated ancient faults, most of these faults have likely been inactive for millions of years. The magnetic data exhibit many gradient lineaments that are optimally oriented for fault slip, and the earthquake data suggest additional optimally oriented faults. Together these data suggest the presence of potentially numerous seismogenic faults throughout the region, which may contribute to high levels of induced seismicity.

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Section: Geologic Backgroundmentioning

confidence: 99%

Aeromagnetic Data Reveal Potential Seismogenic Basement Faults in the Induced Seismicity Setting of Oklahoma

Shah

Crain

2018

Geophysical Research Letters

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“…Some long N-S trending faults from Marsh and Holland (2016) are labeled, including the Nemaha Fault, Wilzetta Fault, Keokuk Fault, and the Galena Township Fault. The figure also labels the geological province in the south of Oklahoma (Northcutt & Campbell, 1969).…”

Section: Effect Of the Friction Coefficientmentioning

confidence: 99%

Deciphering the Stress State of Seismogenic Faults in Oklahoma and Southern Kansas Based on an Improved Stress Map

et al. 2019

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Fault location and geometry are critical considerations in the reactivation of preexisting faults. Here, we combine relocated earthquake catalogs and focal mechanisms to delineate seismogenic faults in Oklahoma and southern Kansas and analyze their stress state. We first identify and map seismogenic faults based on earthquake clustering. We then obtain an improved stress map using 2,047 high‐quality focal mechanisms. The regional stress map shows a gradual transition from oblique normal faulting in western Oklahoma to strike‐slip faulting in central and eastern Oklahoma. Stress amplitude ratio shows a strong correlation with pore pressure from hydrogeologic models, suggesting that pore pressure exhibits a measurable influence on stress patterns. Finally, we assess fault stress state via 3‐D Mohr circles; a parameter understress is used to quantify the level of fault criticality (with 0 meaning critically stressed faults and 1 meaning faults with no applied shear stress). Our results indicate that most active faults have near vertical planes (planarity >0.8 and dip >70°), and there is a strong correlation between fault length and maximum magnitude on each fault. The fault trends show prominent conjugate sets that strike [55–75°] and [105–125°]. A comparison with mapped sedimentary faults and basement fractures reveals common tectonic control. Based on 3‐D Mohr circles, we find that 78% of the faults are critically stressed (understress ≤0.2), while several seismogenic faults are misoriented with high understress (>0.4). Fault geometry and local stress fields may be used to evaluate potential seismic hazard, as the largest earthquakes tend to occur on long, critically stressed faults.

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“…has no known historical seismicity [Northcutt and Campbell, 1995;McBee, 2003;Bennison, 1964;Joseph, 1987] ( Figures 1 and 3). ΔCFS calculations for the Cushing sequence (following Stein et al, 1997;Stein, 1999) indicate that the Wilzetta-Whitetail fault zone has, as a result of the recent earthquake sequence, experienced positive static stress changes (>0.1 bar) over a length of at least 8 km south of Cushing (Figures 1 and S2).…”

Section: 1002/2015gl064669mentioning

confidence: 99%

Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure

McNamara

Hayes

Benz

et al. 2015

Geophys. Res. Lett.

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In October 2014 two moderate‐sized earthquakes (Mw 4.0 and 4.3) struck south of Cushing, Oklahoma, below the largest crude oil storage facility in the world. Combined analysis of the spatial distribution of earthquakes and regional moment tensor focal mechanisms indicate reactivation of a subsurface unnamed and unmapped left‐lateral strike‐slip fault. Coulomb failure stress change calculations using the relocated seismicity and slip distribution determined from regional moment tensors, allow for the possibility that the Wilzetta‐Whitetail fault zone south of Cushing, Oklahoma, could produce a large, damaging earthquake comparable to the 2011 Prague event. Resultant very strong shaking levels (MMI VII) in the epicentral region present the possibility of this potential earthquake causing moderate to heavy damage to national strategic infrastructure and local communities.

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Geologic Provinces of Oklahoma

Cited by 12 publications

References 4 publications

Aeromagnetic Data Reveal Potential Seismogenic Basement Faults in the Induced Seismicity Setting of Oklahoma

Aeromagnetic Data Reveal Potential Seismogenic Basement Faults in the Induced Seismicity Setting of Oklahoma

Deciphering the Stress State of Seismogenic Faults in Oklahoma and Southern Kansas Based on an Improved Stress Map

Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure

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