Pore Pressure Effect on Coulomb Stress Change and Triggering of Earthquakes in Raton Basin, Colorado – New Mexico Region
Description:
The Raton Basin, located in southern Colorado and northern New Mexico, is an actively producing hydrocarbon basin that has undergone increased seismicity since 2001, which is attributed to anthropogenic perturbations resulting from wastewater injection. To better understand how changes in pore pressure and shear stress along faults give rise to earthquake sequences, we investigate the spatio-temporal evolution of static Coulomb stress changes associated with nine seismic events of magnitude Mw>4 that occurred in the Raton Basin between 2001 and 2011. Examining the distribution of stress provides insights into whether subsequent earthquake events in the region are triggered or delayed. Wastewater injection operations in the region have raised pore pressures in nearby fault zones, increasing the likelihood of inducing slip or triggering earthquakes on critically stressed faults. Pore pressure effect cannot be neglected, and we further examine how it affects Coulomb stress. Our analysis reveals that the 2011 Mw 5.3 earthquake, the largest magnitude event occurred in the basin, was likely triggered by cumulative static stress changes and pore pressure increases resulting from the prior seismicity from 2001 to 2005. We find notable differences of approximately 0.1 MPa in our models of stress change when including versus excluding the effects of pore pressure. This is significantly higher than the 0.01 MPa change typically considered sufficient to trigger seismicity. Our results show that pore pressure can significantly affect modeled Coulomb stress changes over time. Careful monitoring of pore pressure changes, combined with modeling of stress interactions across regional fault networks, is critical for understanding induced seismicity hazards in regions undergoing continued wastewater injection. Incorporating pore pressure data into stress change models enhances the insights into earthquake triggering and aftershock forecasting.
Session: Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards [Poster Session]
Type: Poster
Date: 5/1/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Fabiana
Student Presenter: Yes
Invited Presentation:
Authors
Fabiana Fuentes Presenting Author Corresponding Author fafu5236@colorado.edu University of Colorado Boulder |
Manuel Mendoza manuel.Mendoza@colorado.edu University of Colorado Boulder |
Megan Brown mbrown18@niu.edu Northern Illinois University |
Shemin Ge ges@colorado.edu University of Colorado Boulder |
Anne Sheehan Anne.Sheehan@colorado.edu University of Colorado Boulder |
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Pore Pressure Effect on Coulomb Stress Change and Triggering of Earthquakes in Raton Basin, Colorado – New Mexico Region
Session
Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards