Quaternary Rates of Slip for faults of the Central Walker Lane

Stephen J. Angster, Steven G. Wesnousky, Lewis A. Owen, Paula M. Figueiredo, & Sarah Hammer

Submitted August 15, 2017, SCEC Contribution #7771, 2017 SCEC Annual Meeting Poster #139

The Walker Lane shear zone trends northwest along the eastern Sierra Nevada and accommodates a significant portion of North American-Pacific Plate relative transform motion. In the central portion of the Walker Lane, the Benton Springs, Petrified Springs, Gumdrop Hills, and Indian Head faults are identified as the main Quaternary active strike-slip faults that accommodate some portion of the geodetically observed ~8 mm/yr of northwest directed transtensional dextral shear measured across the region. Here, we are placing quantitative geologically constrained limits on the shear and extensional components of slip determined from Quaternary mapping of high-resolution topographic datasets, including lidar and structure-from-motion, and 10Be and Cl36 cosmosgenic nuclide dating and soil characterization of offset alluvial fans along each of the main faults. Thus far, results yield late-Pleistocene-Holocene strike-slip rates for the Benton Springs, Gumdrop Head, and Indian Head faults of 1.8 ± 0.6 mm/yr, 0.6 ± 0.4 mm/yr, and <0.9 mm/yr, respectively, and we are awaiting results for the Petrified Springs fault. The extensional component of slip appears to be minimal for these faults, with a maximum determined rate of 0.12 mm/yr on the Benton springs fault, assuming a minimum dip of 60 degrees. Thus far, these rates agree with prior qualitative estimates and are at the high end of rates predicted by others from geodetic block modeling.

Key Words
Slip rates, Walker Lane, Quaternary, Geomorphology

Citation
Angster, S. J., Wesnousky, S. G., Owen, L. A., Figueiredo, P. M., & Hammer, S. (2017, 08). Quaternary Rates of Slip for faults of the Central Walker Lane. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Earthquake Geology