Rupture of an Immature Fault in the Pawnee Mw5.8 earthquake

Kathleen M. Keranen, Heather M. Savage, Genevieve L. Coffey, Rowena B. Lohman, Catherine Lambert, Nathan Stevens, & Hannah S. Rabinowitz

Submitted August 16, 2017, SCEC Contribution #7891, 2017 SCEC Annual Meeting Poster #200

Earthquakes across north-central Oklahoma demonstrate considerable variability, with some areas remaining nearly aseismic despite abundant injection. Where earthquakes do occur, they largely rupture unmapped faults, even in regions where mapped faults exist. The Pawnee earthquake occurred on one such fault, with multiple, well-oriented fault segments rupturing during the aftershock sequence. Here we present results of the Pawnee aftershock sequence from a combination of broadband seismometers and a dense nodal array. Results suggest that the fault ruptured an immature fault that is not yet a well-developed, through-going fault plane, with the complex rupture possibly facilitated by the enhanced fluid pressure throughout this zone. Similar to the Pawnee earthquake, earthquakes in northern Oklahoma largely occur on unmapped faults, suggesting that basement throughout the region is pervasively fractured and faulted.

Citation
Keranen, K. M., Savage, H. M., Coffey, G. L., Lohman, R. B., Lambert, C., Stevens, N., & Rabinowitz, H. S. (2017, 08). Rupture of an Immature Fault in the Pawnee Mw5.8 earthquake. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)