S010-0001
Generation of synthetic ground motions for induced seismic events in Oklahoma using varied fault orientations
Tuesday, 8 December 2020
Poster
Harriet Zoe Yin1, Jessie K Saunders2, Jennifer S Haase1, Imran A Sheikh3, Mohamed Soliman3, Frankie Martinez1, Priyank Jaiswal4 and Ignacio Sepulveda1, (1)University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States, (2)U.S. Geological Survey, Earthquake Science Center, Moffett Field, CA, United States, (3)Oklahoma State University, School of Civil and Environmental Engineering, Stillwater, OK, United States, (4)Oklahoma State University, Boone Pickens School of Geology, Stillwater, OK, United States
Abstract:
Realistic ground motions for near-field source scenarios are important to quantitatively model the hazard posed to critical infrastructure by induced seismicity in Oklahoma. Available physics-based models have provided descriptions of relatively high and low hazard areas within Oklahoma and demonstrated that faults oriented favorably relative to the regional stress field are more likely to produce induced earthquakes. However, uncertainties around descriptions of hazard remain large and it is not well understood which faults pose the greatest hazard. Ground motions modeled from a variety of source types can provide a more complete picture of local hazard. We use semi-stochastic kinematic rupture modeling methods to generate synthetic ground motions for scenario events in Oklahoma, with the goal of understanding the range of realistic near-field ground motions. We have particular interest in the region surrounding Stillwater, Oklahoma, where we have instrumented an aging multistory reinforced concrete building on the Oklahoma State University (OSU) campus with GNSS receivers, accelerometers, and gyroscopes as part of an NSF-sponsored research project measuring and simulating the building response.
The 2016 M5.8 Pawnee earthquake was the largest earthquake on record in this region, resulted in significant ground motions, and prompted the regulation of injection rates. We first model the waveforms recorded from this earthquake to adjust the velocity structure and to verify that our synthetic waveforms match observed ground motions and are consistent with regional ground motion prediction equations. We then investigate a variety of source scenarios with different fault orientations and compare their respective ground motions at Stillwater. In particular, we produce synthetic ground motions for a hypothetical M6.0 event on the Lake Carl Blackwell Fault, which is optimally aligned with the regional stress field and bears geologic evidence of recent activity. The Lake Carl Blackwell Fault is near the OSU campus, so an earthquake on this fault poses high hazard to the area, especially to aging infrastructure. These data will be of great value to both the geoscience and civil engineering communities for coupling numerical models of buildings to models that predict ground motion.
