A Broad, Distributed Active Fault Zone Lies beneath Salt Lake City, Utah

Abstract Although the Wasatch fault is currently known to have a high-seismic hazard from motion along range-bounding faults, new seismic data reveal faulted and folded 13,000–30,000-yr-old Lake Bonneville strata beneath Salt City (SLC). Coupled with previous excavation trench, borehole, other geologic geophysical observations, we conclude that zone of latest Pleistocene and/or Holocene faulting folding kinematically links East Bench Warm Springs faults through 3 km wide relay structure transfer zone. We characterize downtown SLC as active, these may displace or deform ground surface during an earthquake. Through offset but linked our observations support throughgoing ruptures across (WFZ) elevated risk earthquake-induced building damage.