Date of Award

12-2014

Document Type

Thesis

Degree Name

Master of Science in Earth and Environmental Sciences

Department

Geological Sciences

First Reader/Committee Chair

McGill, Sally

Abstract

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.

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