TY - JOUR
T1 - Pore-pressure diffusion, enhanced by poroelastic stresses, controls induced seismicity in Oklahoma
AU - Zhai, Guang
AU - Shirzaei, Manoochehr
AU - Manga, Michael
AU - Chen, Xiaowei
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank the Oklahoma Corporation Commission and Oklahoma Geological Survey for making the underground injection data and seismic catalog publicly available. G.Z., M.S., and M.M. are supported by Department of Energy Grant DE-SC0019307. X.C. is supported by US Geological Survey Grant G18AP00022 and University of Oklahoma McCoy Fund.
Funding Information:
We thank the Oklahoma Corporation Commission and Oklahoma Geological Survey for making the underground injection data and seismic catalog publicly available. G.Z., M.S., and M.M. are supported by Department of Energy Grant DE-SC0019307. X.C. is supported by US Geological Survey Grant G18AP00022 and University of Oklahoma McCoy Fund.
Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
PY - 2019/8/13
Y1 - 2019/8/13
N2 - Induced seismicity linked to geothermal resource exploitation, hydraulic fracturing, and wastewater disposal is evolving into a global issue because of the increasing energy demand. Moderate to large induced earthquakes, causing widespread hazards, are often related to fluid injection into deep permeable formations that are hydraulically connected to the underlying crystalline basement. Using injection data combined with a physics-based linear poroelastic model and rate-and-state friction law, we compute the changes in crustal stress and seismicity rate in Oklahoma. This model can be used to assess earthquake potential on specific fault segments. The regional magnitude–time distribution of the observed magnitude (M) 3+ earthquakes during 2008–2017 is reproducible and is the same for the 2 optimal, conjugate fault orientations suggested for Oklahoma. At the regional scale, the timing of predicted seismicity rate, as opposed to its pattern and amplitude, is insensitive to hydrogeological and nucleation parameters in Oklahoma. Poroelastic stress changes alone have a small effect on the seismic hazard. However, their addition to pore-pressure changes can increase the seismicity rate by 6-fold and 2-fold for central and western Oklahoma, respectively. The injection-rate reduction in 2016 mitigates the exceedance probability of M5.0 by 22% in western Oklahoma, while that of central Oklahoma remains unchanged. A hypothetical injection shut-in in April 2017 causes the earthquake probability to approach its background level by ∼2025. We conclude that stress perturbation on prestressed faults due to pore-pressure diffusion, enhanced by poroelastic effects, is the primary driver of the induced earthquakes in Oklahoma.
AB - Induced seismicity linked to geothermal resource exploitation, hydraulic fracturing, and wastewater disposal is evolving into a global issue because of the increasing energy demand. Moderate to large induced earthquakes, causing widespread hazards, are often related to fluid injection into deep permeable formations that are hydraulically connected to the underlying crystalline basement. Using injection data combined with a physics-based linear poroelastic model and rate-and-state friction law, we compute the changes in crustal stress and seismicity rate in Oklahoma. This model can be used to assess earthquake potential on specific fault segments. The regional magnitude–time distribution of the observed magnitude (M) 3+ earthquakes during 2008–2017 is reproducible and is the same for the 2 optimal, conjugate fault orientations suggested for Oklahoma. At the regional scale, the timing of predicted seismicity rate, as opposed to its pattern and amplitude, is insensitive to hydrogeological and nucleation parameters in Oklahoma. Poroelastic stress changes alone have a small effect on the seismic hazard. However, their addition to pore-pressure changes can increase the seismicity rate by 6-fold and 2-fold for central and western Oklahoma, respectively. The injection-rate reduction in 2016 mitigates the exceedance probability of M5.0 by 22% in western Oklahoma, while that of central Oklahoma remains unchanged. A hypothetical injection shut-in in April 2017 causes the earthquake probability to approach its background level by ∼2025. We conclude that stress perturbation on prestressed faults due to pore-pressure diffusion, enhanced by poroelastic effects, is the primary driver of the induced earthquakes in Oklahoma.
KW - Induced seismicity
KW - Poroelasticity
KW - Seismic hazard forecasting
KW - Seismicity rate
KW - Waste fluid injection
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U2 - 10.1073/pnas.1819225116
DO - 10.1073/pnas.1819225116
M3 - Article
C2 - 31358640
AN - SCOPUS:85070600728
SN - 0027-8424
VL - 116
SP - 16228
EP - 16233
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 33
ER -