Tue, Feb 08
|Online Zoom Presentation
Dallas Geological Society Luncheon February 2022
Waking the Sleeping Giants: Basement-Rooted Deformation and the Injection Induced Seismicity of U.S. Mid Continent Folarin Kolawole Structural Geologist at BP America Adjunct Associate Research Scientist at Lamont-Doherty Earth Observatory, Columbia University
Time & Location
Feb 08, 2022, 12:00 PM – 1:50 PM
Online Zoom Presentation
About The Event
The recent widespread seismicity of the U.S. Mid Continent is attributed to the reactivation of pre-existing basement faults by wastewater injection. However, only limited details are known for inherited geological and geomechanical structure of the basement faults, and their implications for 1) the susceptibility of the basement to seismic triggering, and 2) the spatial distribution of the seismicity. These knowledge gaps also impact the ability to identify the presence of potentially seismogenic faults prior to drilling and fluid injection in the region. By integrating field observations, structural interpretations from 3-D seismic reflection data, earthquake data, and laboratory rock mechanics, I investigated how the inherited structural and mechanical weakness of the pre-existing basement deformation influence the anomalous spatial patterns of injection-induced basement-hosted seismicity in Oklahoma and other nearby areas.
In my talk, I will show my research results revealing that the basement of the earthquake-prone Mid-Continent sub-regions hosts dominant tectonic fabric sets that are well-oriented for strike-slip reactivation in the current regional stress field. In the Oklahoma sub-region, I will show how the geometry and upward propagation styles of the basement-rooted faults influence the present-day susceptibility of the basement to induced seismicity and pose challenges for geophysical illumination of the faults within the sedimentary injection zones. In addition, the rock-mechanics testing of the frictional stability of the Oklahoma basement rocks and its associated geochemical alterations explains the most common depth interval of seismogenic fault reactivation in the Oklahoma basement. In summary, my studies present a case for the significant control of structural inheritance on the patterns of induced fault reactivation by regional fluid injection in the U.S. Mid-Continent.