Paleoseismology of Utah, Volume 17: Paleoseismic investigation of the northern strand of the Nephi segment of the Wasatch fault zone at Santaquin, Utah (SS-124)

By: C. B. DuRoss, G. N. McDonald, and W. R. Lund

This Utah Geological Survey Special Study, Paleoseismic Investigation of the Northern Weber Segment of the Wasatch Fault Zone at the Rice Creek Trench Site, North Ogden, Utah, is the eighteenth report in the Paleoseismology of Utah series. This series makes the results of paleoseismic investigations in Utah available to geoscientists, engineers, planners, public officials, and the general public. These studies provide critical information regarding paleoearthquake parameters such as earthquake timing, recurrence, displacement, slip rate, fault geometry, and segmentation, which can be used to characterize potential seismic sources and evaluate the long-term seismic hazard of Utah’s Quaternary faults.

This report presents the results of a study partially funded through the National Earthquake Hazards Reduction Program to characterize the relative level of activity of the northern strand of the Nephi segment of the Wasatch fault zone (WFZ). The Nephi segment consists of distinct northern and southern strands, and all previous paleoseismic investigations on the segment have been conducted on the southern strand. To resolve issues related to similarities or differences in the timing, displacement, and magnitude of prehistoric surface-faulting earthquakes between the strands, the Utah Geological Survey excavated two trenches on the northern strand at Santaquin while the U.S. Geological Survey simultaneously excavated two trenches at Willow Creek on the southern strand (reported elsewhere). Determining paleoseismic parameters for the entire Nephi segment is important because the new data will help refine segmentation models for the Nephi and Provo segments, which are key components of understanding the past (Holocene) and future behavior of the WFZ, improving WFZ hazard models, and reducing Utah’s earthquake-related risk.

Other Information:
Published: 2008
Pages: 30 p. + 3 p. appendix
Plates: 2 pl.
Location: Utah County