The Garlock Fault consists of three distinct segments, known as western, central, and eastern, together reaching approximately 260 km from the San Andreas Fault to the southern end of Death Valley. Although published slip rates are available along the western and central Garlock Fault segments, little is currently known of the Garlock Fault earthquake history or slip rate farther east. Using LiDAR and satellite imagery, the central and eastern Garlock Fault segments were analyzed for visibly offset, fault-adjacent, geomorphic surfaces that may potentially be used for estimating slip rate. Qualitative methods of assessing preserved alluvial surface maturity were adapted and used to establish unit age categories. Qualitative comparisons of late Pleistocene-Holocene surfaces reveal that the total offset at sites along the eastern Garlock Fault are less than half that of sites of comparable age along the central Garlock Fault, suggesting a significant reduction in slip rate across the intersection of the Brown Mountain, Owl Lake, and Garlock Faults. Digitally-measured offsets and their age groups were plotted in order to achieve preliminary slip-rate estimates. The resulting plot shows an eastward decrease in late Pleistocene-Holocene slip rate at sites along the central and eastern Garlock Fault segments. The central Garlock Fault slip-rate estimate taken from Slate Range West and Slate Range East sites in Pilot Knob Valley is approximately 4.2 mm/yr, within the error (but on the low side) of previously published rates. The slip-rate estimate from the Quail Mountains site, at the easternmost extent of the central Garlock Fault, is approximately 2.7 mm/yr. The slip-rate estimate from the Avawatz section of the eastern Garlock Fault is approximately 1.0 mm/yr.

In this study, a paleoseismic trench with limited age constraints that was previously excavated in 1990 across the central Garlock Fault near Christmas Canyon, in Searles Valley, California, was reopened to take advantage of new advances in luminescence dating techniques to investigate potential temporal variability in earthquake recurrence on the Garlock fault and to analyze previously unexposed older earthquake evidence. The trench exposed interbedded alluvial sand and pebble-gravels, with well-sorted, rounded, lacustrine sand from the most recent highstand of pluvial Lake Searles present at the base of the trench. Preliminary findings suggest at least 10 surface rupturing earthquake events occurred during the 10 k.y. time period exposed in the trench. To provide age constraints on the paleo-surface-rupturing events from the new trench, 54 luminescence samples were collected and the single-grain luminescence dating technique post- - was employed. The ages indicated that 7 events have occurred in the past ~7.2 ka, with at least 3 additional events in the more poorly stratified deeper section of the trench. This suggests a recurrence interval of ~1000 years. Event pattern seen at this trench did not exactly replicate the same pattern at other paleoseismic sites along the Garlock Fault. The most recent event seen at this trench occured within the same time period as the most recent events seen at the other paleoseismic sites on the central Garlock Fault.