Bubnis said the museum still is waiting for structural engineers to determine when it's safe to go back inside the Skydome area.
The museum is about a quarter mile from GM's Bowling Green Assembly Plant, where Corvettes have been made since 1981.
That region of south central Kentucky contains many caves and sinkholes, known as "karst" topography. Mammoth Cave National Park is about 20 miles from Bowling Green.
"It's not uncommon for us to see sinkhole collapses," said city spokeswoman Kim Lancaster. "Most are significantly smaller than the one we have today."
Bowling Green city hydrologist Tim Slattery said when the museum was constructed, builders "did do their due diligence" on the area's geography. But sinkholes can develop over time, as water goes underground and carries soil with it, he said.