Reconnaissance of the Draper Heights landslide and other possible earthquake-induced, shallow, disrupted soil and rock slides in Draper, Utah (OFR-519)

By: F. X. Ashland

Earthquake-induced landslides, with the exception of liquefaction-induced lateral spreads, have not been recognized in the Salt Lake City metropolitan area. This study assesses the feasibility of identifying such earthquake-induced landslides, given the documented latest Pleistocene to present surface-faulting chronology for the Wasatch fault zone and mapped hillslope areas with moderate to high potential for shallow, disrupted slides. Previous researchers mapped a high earthquake-induced shallow landslide hazard on the northwest slope of Steep Mountain, but did not identify any earthquake-triggered slides.

This study identifies the Draper Heights landslide as a possible earthquake-induced, shallow, disrupted soil slide, one of the most common landslide types triggered by the 1994 Northridge earthquake. Other nearby flat-bottomed scars upslope of cone-shaped deposits are also possible earthquake-induced, shallow, disrupted soil slides. Limited opportunities exist for radiocarbon and cosmogenic dating of the slides. The Draper Heights landslide postdates the Bonneville shoreline and thus overlaps in age with the documented surface-faulting chronology of the Wasatch fault zone. Slope-stability analysis, however, suggests that this and other possible landslides on the northwest slope of Steep Mountain may be triggered by earthquakes of smaller magnitude than surface-faulting events.

Other Information:
Published: 2008
Pages: 11 p.
Location: Salt Lake County
Media Type: Paper Publication