NORFOLK, Neb. — A series of loud, unexplained booming sounds reported by 10 people along the lakeshore in Norfolk has been traced to pile-driving work for a private shoreline-stabilization project, investigators said.

The sounds came from equipment setting support pilings at the Willow Bend Lake shoreline, where crews were reinforcing an eroding bank. Cassius Castellano, one of the witnesses, reported hearing several sharp booms carry across the water before learning the source was nearby construction work.

Investigators said the reports represent one occurrence this month. The work was a mundane explanation for the noise, though its sound traveled farther than expected over the lake.