The Lavic Lake fault: a long-term cumulative slip analysis via combined field work and thermal infrared hyperspectral airborne remote sensing

Rebecca A. Witkosky, Joann M. Stock, David M. Tratt, Kerry N. Buckland, Paul M. Adams, Patrick D. Johnson, David K. Lynch, & Francis J. Sousa

In Preparation September 1, 2020, SCEC Contribution #8898

The 1999 Hector Mine earthquake ruptured to the surface in eastern California, with >5 m peak right-lateral slip on the Lavic Lake fault. The cumulative offset and geologic slip rate of this fault are not well defined, which inhibits tectonic reconstructions of the Eastern California shear zone (ECSZ). With thermal infrared hyperspectral airborne imagery, field data, and auxiliary information from legacy geologic maps, we created lithologic maps of the area using supervised and unsupervised classifications of the remote sensing imagery. We optimized a data processing sequence for supervised classifications, resulting in lithologic maps over a test area with an overall accuracy of 71±1%. Using all of the data and maps, we identified offset bedrock features that yield piercing points along the main Lavic Lake fault and indicate a 1035 +24/-27 m net slip. For the contribution from distributed shear, modern off-fault deformation values from another study imply a larger cumulative slip of 1310 +30/-34 m. Within the constraints, we estimate a geologic slip rate of <4 mm/yr, which does not increase the sum geologic Mojave ECSZ rate to current geodetic values. Our result supports previous suggestions that transient tectonic activity in this area may be responsible for the discrepancy between long-term geologic and present-day geodetic rates.

Key Words
Hector Mine earthquake; Lavic Lake fault; thermal infrared hyperspectral airborne imagery, net slip, eastern California shear zone

Citation
Witkosky, R. A., Stock, J. M., Tratt, D. M., Buckland, K. N., Adams, P. M., Johnson, P. D., Lynch, D. K., & Sousa, F. J. (2020). The Lavic Lake fault: a long-term cumulative slip analysis via combined field work and thermal infrared hyperspectral airborne remote sensing. Remote Sensing, (in preparation).