The Wasatch fault is a 370-km-long zone of normal faulting that forms the eastern edge of the Basin and Range Province in Utah and southeastern Idaho. The fault zone is subdivided into ten segments that range from 30 to 60 km in length and are each capable of generating earthquakes of M ~7. For the five central segments, multiple surface-faulting earthquakes have occurred during the Holocene, and vertical slip rates are ~1 mm/yr. Recurrence intervals for the individual central segments range from ~1300 to 2500 yr. The fault poses a significant seismic hazard to the highly urbanized Wasatch Front in north-central Utah. The field localities described in this guide provide an overview of the surface and subsurface character of the Wasatch fault zone. Five field trip stops are located along the Nephi, Provo, and Salt Lake City segments. We will observe fault scarps on Quaternary deposits, which record tectonic displacements associated with Holocene earthquakes, and fault-zone rocks exhumed from depths in excess of 10 km that are hydrothermally altered and have evidence of brittle and ductile deformation. Specific topics of discussion include the nature of piedmont fault scarps; the use of paleoseismic trenching and fault-scarp geomorphology to infer earthquake timing, recurrence intervals, and fault slip rates; and the subsurface structure and rheology of the fault.

Keywords: faulting, paleoseismology, neotectonics, earthquake geology.