The 180-km-long Meers-Willow Fault System in the Southern Oklahoma Aulacogen: A potential U.S. mid-continent seismic hazard

Geological Society of America Bulletin
By: , and 



We integrate new high-resolution aeromagnetic data with seismic reflection data, well logs, satellite remote sensing, and field observations to provide a regional view of buried and exposed structures in the Southern Oklahoma Aulacogen and to assess their potential for future seismicity. Trends ranging from NW−SE to ∼E−W, peaking at 330° ± 4.5° and 280° ± 3°, dominate the magnetic lineaments of the Southern Oklahoma Aulacogen, reflecting basement contacts, dikes, and faults, including a previously unmapped ∼100-km-long basement fault, which is herein referred to as the Willow fault. The fault disrupts, truncates, and vertically offsets basement-related seismic reflectors and overlying Paleozoic strata up through the Permian reflectors. Surface deformation along the trend includes fault-parallel monoclinal folds, pervasive fractures, and fracture-hosted mud dikes in Permian evaporite units. These structures indicate a Permian or post-Permian reactivation of the fault. Along-strike, the Willow fault connects to the NW-trending, seismically active Meers Fault to comprise the ∼180-km-long Meers-Willow fault system, which potentially represents a major seismic hazard along the Southern Oklahoma Aulacogen. Fault slip potential analyses of the mapped potential fault traces show that seismic hazards are elevated where faults have steeper dips. Given some uncertainty in the regional stress state, we also show that hazards along the NW−SE to E−W trending faults vary considerably within the uncertainty range. We propose that the Meers-Willow fault system originated as a Cambrian aulacogen-scale, basement-rooted fault that was later reactivated as a left-lateral strike-slip fault (with ∼40 km displacement) during the late Paleozoic Ancestral Rocky Mountain orogeny, highlighting that lateral offset accommodated a major component of deformation during the orogen.

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Publication type Article
Publication Subtype Journal Article
Title The 180-km-long Meers-Willow Fault System in the Southern Oklahoma Aulacogen: A potential U.S. mid-continent seismic hazard
Series title Geological Society of America Bulletin
DOI 10.1130/B36363.1
Volume 135
Issue 3-4
Year Published 2023
Language English
Publisher Geological Society of America
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description 15 p.
First page 663
Last page 677
Country United States
State Oklahoma
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