A systematic assessment of the spatio-temporal evolution of fault activation through induced seismicity in Oklahoma and southern Kansas

Martin Schoenball, & William L. Ellsworth

Published August 10, 2017, SCEC Contribution #7473, 2017 SCEC Annual Meeting Poster #044

Much of Oklahoma and Southern Kansas has seen widespread seismic activity in the last decade that is attributed to large-scale wastewater disposal into the Arbuckle group. Using a waveform-relocated earthquake catalog, we perform a systematic study of the activity on several hundreds of identified faults. We use 93 sequences with at least 30 events for a detailed analysis of their spatio-temporal evolution. For most awakened faults, seismicity tends to initiate at shallower depth and migrates deeper along the faults as the sequence proceeds. No major sequence starts with the largest earthquake and many sequences initiate months before they rise to peak activity. We study temporal clustering as a means to quantify earthquake interactions. Some sequences show no temporal clustering similar to Poissonian background seismicity but at much higher rate than the natural background. Other sequences exhibit strong temporal clustering akin to mainshock-aftershock sequences. We conclude that once initiated by anthropogenic forcing, portions of the activated faults in the Oklahoma/Kansas area are close enough to failure to continue to fail through earthquake interaction. We show that the largest earthquakes occur as a result of continued anthropogenic forcing. In many sequences seismicity continues to populate the previously activated region, rather than growing the activated area. Therefore, improved monitoring has the potential to detect minor activity as it initiates failure on specific faults and thus provide warning time to take actions to mitigate the occurrence of potentially damaging earthquakes.

Citation
Schoenball, M., & Ellsworth, W. L. (2017, 08). A systematic assessment of the spatio-temporal evolution of fault activation through induced seismicity in Oklahoma and southern Kansas. Poster Presentation at 2017 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology