HYRUM, Utah -- Engineers are drilling to determine the composition of the 75-year-old Hyrum Dam and whether it would hold up to a major earthquake.
The work will take about a week. It has resulted in the closure of some lanes on Hyrum's 300 South Street.
U.S. Bureau of Reclamation geologists Ira Terry says the drilling will reveal any soft spots or sand layers in the dam that could liquefy under strong shaking from an earthquake.
Terry says the dam or spillways could be shored up if engineers find a problem.
The Hyrum dam on the Little Bear River holds back a 438-acre reservoir used for flood control and irrigation.
Hyrum is about 60 miles north of Salt Lake City.