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Constructing a 3-D radially anisotropic crustal velocity model for Oklahoma using full waveform inversion
  • Shuo Zhang,
  • Hejun Zhu
Shuo Zhang
University of Texas at Dallas
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Hejun Zhu
University of Texas at Dallas

Corresponding Author:[email protected]

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Abstract

Over the past decade, the seismicity rate in the state of Oklahoma has increased significantly, which has been linked to industrial operations, such as saltwater injection. Taking advantage of induced earthquakes and recently deployed seismometers, we construct a 3-D radially anisotropic seismic velocity model for the crust of Oklahoma by using full waveform inversion. To mitigate the well-known cycle-skipping problem, we use misfit functions based on phase and waveform differences in several frequency bands. Relative velocity perturbations in the inverted model allow us to delineate major geological provinces in Oklahoma, such as the Anadarko and Arkoma Basins, as well as the Cherokee Platform and Shelf. In addition, radial anisotropy in the inverted model reflects deformation within the crust of Oklahoma, which might correlate with sedimentary layers, micro-cracks/fractures, as well as the dominant orientation of anisotropic minerals. The crystalline basement beneath Oklahoma can be inferred from the new velocity model, which enables us to classify induced seismicity in current earthquake catalogs better. Furthermore, synthetic experiments suggest that the new velocity model enables us to better constrain earthquake location in Oklahoma,
especially for determining their depths, which are important for investigating induced seismicity.
07 May 2023Submitted to ESS Open Archive
08 May 2023Published in ESS Open Archive