Scientists are essentially performing a CT scan on Mount Baldy to discover why the Indiana Dunes National Lakeshore destination has huge, unexpected holes that can swallow people.

The current theory is that decomposing trees, broken-down houses and various objects buried in the last 70 years by a shifting sand dune created the bizarre hole that gulped down a 6-year-old boy at the site last summer, National Geographic reported.

Scientists are developing a three-dimensional map of everything that could be buried underneath the sand, studying what's under the dune's surface with radar that goes as far as 75 feet down. 

The boy, who is alive and well after the rescue, was covered with 11 feet of fine sand for three and a half hours after he dropped into the sudden hole.

Six more holes have been discovered since the incident, and the park has been closed indefinitely for the nearly 2 million visitors that come to the spot each year.

"We want to let the science do the talking before we do any management decisions as to whether to open Mount Baldy," said Bruce Rowe, spokesman for the Indiana Dunes National Lakeshore, as quoted by the Daily Journal. "We have a great desire to reopen it. It's one of the most popular areas in the lakeshore. But we want to make sure we understand what's going on from a geological standpoint so we can make the proper decisions."

Part of the dune's fine sand comes from sediment around the Lake Michigan. Another factor is the mark left by park visitors have been exploring the area for decades, causing detriment to plant life that helped to keep Mount Baldy's fine sand in place.

Funded by a grant from the National Park Service, the full study will cost $90,000 and is scheduled for an initial report in three months, a preliminary report in six months and a final report in a year, according to the Daily Journal. 

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