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A Ground Motion Prediction Equation for Earthquakes Mw 4-6 in Oklahoma and Kansas Derived from a Composite Recorded/Simulated Ground Motion Catalog

Samuel A. Bydlon, Kyle B. Withers, & Eric M. Dunham

Published August 14, 2017, SCEC Contribution #7657, 2017 SCEC Annual Meeting Poster #263

Recent increases in seismic activity in historically quiescent areas such as Oklahoma, Texas, and Arkansas have spurred the need for an investigation into expected ground motions associated with these seismic sources. This seismicity increase corresponds to a scarcity of ground motion recordings within ~20 km of earthquakes Mw 3 and greater. We extend off of previous work, in which simulated earthquake ground motions from Mw 3-4 earthquakes were integrated into a recorded ground motion catalog to aid GMPE development in a target region encompassing Oklahoma and Kansas. Recorded ground motions for this area are available through the end of 2016 and include the 3 September, 2016 Mw 5.8 event near Pawnee, OK. Here, we use dynamic rupture simulations with heterogeneous initial stress conditions to simulate earthquakes Mw 4-6. We use a layered velocity model derived from well logs in central/north Oklahoma in the near surface ( < 2.7 km) and the Arbuckle formation overlying basement rock at depth. Despite a lack of recorded near-source ground motions at larger magnitudes, we demonstrate that dynamic simulations can be designed such that the resulting ground motions (up to 5 Hz) exhibit similar characteristics (e.g. amplitudes, decay trends, etc…) to the recorded data from the target area. We use the composite recorded/synthetic ground motion catalog to generate a GMPE for the Oklahoma/Kansas region up to magnitude 5.8 (the largest recorded event in the catalog). This framework can be exported to other regions where near-source ground motion data are sparse and can be used to improve constraints on near-source GMPEs, which could directly benefit seismic hazard estimates for both induced and tectonic earthquakes. Additionally, we attempt to reproduce the suite of dynamically generated earthquakes using point moment tensor sources to understand the effects that a finite fault source has on ground motion with increasing earthquake magnitude.

Bydlon, S. A., Withers, K. B., & Dunham, E. M. (2017, 08). A Ground Motion Prediction Equation for Earthquakes Mw 4-6 in Oklahoma and Kansas Derived from a Composite Recorded/Simulated Ground Motion Catalog. Poster Presentation at 2017 SCEC Annual Meeting.

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Ground Motions