Fracture and Regional Stress Related Upper Crustal Azimuthal Anisotropy in the Vicinity of the 2016 M5.1 Fairview, Oklahoma, Earthquake
Abstract
To explore the possible correlation between wastewater injection and spatial-temporal distribution of upper crustal anisotropy, we conduct shear wave splitting (SWS) analysis using local S waves recorded by six stations in the vicinity of the February 2016 magnitude 5.1 earthquake, which was generally considered to be an inject-induced damaging earthquake. In the vicinity of the main shock, a sharp increase in the magnitude and the number of earthquakes occurred after continuous injection for about 24 months. The spreading directions of the seismicity are revealed to correspond well with the assumed diffusion direction of the injection fluid. A total of 356 pairs of high-quality SWS parameters (fast orientations and splitting times) were obtained using local events occurred in the S-wave window. For raypaths traveling through the fault zone of the M5.1 earthquake, the fast orientations are NE-SW which is parallel to the right lateral strike-slip fault and may reflect fluid-fill fractures; on the other hand, the other raypaths that did not travel through the fault zone show NW-SE fast orientations which are consistent with the direction of the regional maximum compressive stress. Finally, both the fast orientations and the splitting times show some changes after the M5.1 earthquake, although the statistical significance of such temporal variations is unknown due to the small number of pre-earthquake measurements.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S11F0398J
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGY;
- 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGY;
- 7230 Seismicity and tectonics;
- SEISMOLOGY;
- 8168 Stresses: general;
- TECTONOPHYSICS