Evaluating Surface Faulting Chronologies of Graben-Bounding Faults in Salt Lake Valley, Utah- New Paleoseismic Data from the Salt Lake City Segment of the Wasatch Fault Zone and the West Valley Fault Zone
By: Christopher B. DuRoss and Michael D. Hylland
The Salt Lake City segment (SLCS) of the Wasatch fault zone and the West Valley fault zone (WVFZ) are Holocene-active faults that have evidence of large-magnitude (M ~6-7) surface-faulting earthquakes. Paleoseismic research trenches at the Penrose Drive site on the SLCS and Baileys Lake site on the WVFZ provided data that shed light on the faulting behavior and interaction of these graben-forming fault systems. Numerical age control (22 radiocarbon samples 23 optically stimulated luminescence samples) and OxCal modeling of six or seven surface-faulting earthquakes on the SLCS and four earthquakes on the WVFZ helped refine the earthquake chronologies for these faults and allowed a comparison of the chronologies to evaluate fault interaction. The chronologies, as well as vertical displacements, support a model of coseismic fault movement.