Characterizing spatiotemporal stress orientations in regions with induced seismicity

Rob Skoumal

Published August 10, 2021, SCEC Contribution #11229, 2021 SCEC Annual Meeting Poster #188

Induced seismicity predominantly occurs along pre-existing faults that are optimally oriented in the local stress field. The characterization of these spatially varying stresses is a crucial component of understanding and potentially quantifying the seismic hazard in a region. Further, both human activities and earthquakes may alter the local stress field, so it is also important to resolve temporal variations at small spatial scales. We use recordings of induced earthquakes for shear wave splitting (SWS) analyses and moment tensor inversions to produce independent spatiotemporal estimates of maximum horizontal stress directions in California, Kansas, and Oklahoma. We use local seismic networks and a machine learning phase identifier to facilitate the rapid evaluation of large numbers of small magnitude earthquakes. High-quality SWS measurements are selected by investigating the stability of results across a wide variety of frequency bands within earthquake families. The virtual seismometer method is used to constrain moment tensors of small magnitude earthquakes and evaluate non-double couple solutions. With spatiotemporal stress orientation estimates from the complementary SWS and moment tensor inversion methods, we characterize previously identified seismogenic faults in our study regions to determine whether they are favorably or unfavorably oriented to the local stress field.

Key Words
Induced Seismicity, Stress

Skoumal, R. (2021, 08). Characterizing spatiotemporal stress orientations in regions with induced seismicity. Poster Presentation at 2021 SCEC Annual Meeting.

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