NEOTECTONIC ASSESSMENT OF THE SOUTHERN WASSUK RANGE FAULT ZONE, WESTERN NEVADA

The Wassuk Range fault zone (WRFZ) is located in the western Basin-and-Range Province along the California-Nevada border. The WRFZ is an east-dipping, high-angle normal fault that traces 80 km. Prior studies along the northern WRFZ, near Walker Lake, have estimated slip rates of ~1.0 mm/yr. This study assesses the neotectonic activity and kinematic significance of the WRFZ in its southern section around Whiskey Flat in western Nevada. In the study area, the WRFZ corresponds with Quaternary and Holocene fault scarps that occur along the mountain front, as well as within the basin. Subsurface fault geometry is assessed using seismic reflection imaging along a ~500-meter profile. At multiple locations, fault scarps are surveyed using low-altitude photogrammetry to produce high-resolution surface models. Fault scarp degradation modeling, calibrated using a scarp within a previously dated surface, provides a self-consistent set of ages allows assessing spatial variations in slip rate between the northern and southern parts of the WRFZ. This study also makes a preliminary test of possible seismogenic fault segmentation — using the calibrated scarp degradation model, we also can assess whether the timing of the smallest fault scarp (presumably a single surface-rupturing event) is comparable to published paleoseismic results from the northern section of the WRFZ.