Utah Admin. Code 655-11-5B
Results of the geological and seismological studies may be sufficient to evaluate seismic safety. However, if it appears the dam cannot safely withstand the earthquake motions or if sufficient information is not available to make an adequate determination, the next step of a phased evaluation program would be a field investigation and laboratory testing program. Field investigation should include a sufficient number of borings and test pits to accurately define the embankment, foundation, and abutment materials types, properties, and extent. Particular care and sufficient field data should be obtained where potentially liquefiable soils are present. In place and laboratory testing should be performed to adequately assess the material properties under the anticipated dynamic conditions.
Utah Admin. Code R655-11-5B