Coulomb stress interactions during the M (sub w) 5.8 Pawnee sequence
Coulomb stress interactions during the M (sub w) 5.8 Pawnee sequence
Seismological Research Letters (May 2017) 88 (4): 1024-1031
- aftershocks
- body waves
- earthquakes
- elastic constants
- elastic waves
- fault planes
- fault zones
- faults
- fluid injection
- focal mechanism
- focus
- induced earthquakes
- main shocks
- Oklahoma
- P-waves
- Pawnee County Oklahoma
- seismic networks
- seismic waves
- shear modulus
- stress
- United States
- Pawnee earthquake 2016
- Watchorn Fault
- Labette Fault
- Sooner Lake Fault
We investigate the stress interaction between the Watchorn, Labette, and Sooner Lake fault systems and the effect of precursory activities on the 3 September 2016 M (sub w) 5.8 Pawnee earthquake. We obtain fault-plane solutions for earthquakes with sufficient azimuthal coverage using the HASH algorithm, and then perform coulomb stress analysis on both seismogenic faults and individual nodal planes. Our results found that the three M (sub w) > or =3.0 foreshocks exerted a cumulative coulomb stress change increase of 0.68-1.98 bars at the mainshock hypocenter and also promoted failure for most aftershocks within 2 km of the mainshock. The coulomb stress change of 5 bars exerted by the mainshock also promoted failure for most aftershocks within the conjugate fault system. The results suggest that earthquake interaction should be fully considered in hazard assessment for induced seismicity.