Woessner was recovering at Comer Children's Hospital Friday. He was rescued after being buried alive under sand on Mount Baldy in the Indiana Dunes last weekend.
Woessner was upgraded from critical to serious condition on Thursday after he was extubated, doctors said.
The boy was with his parents on Friday, July 12, 2013, when he was swallowed by a sinkhole. He was buried under 11 feet of sand for three hours while crews worked to rescue him at Indiana Dunes National Lakeshore near Michigan City, Ind.
Bruce Rowe, a public information officer with the National Park Service, said in a release Thursday that geologists with the Park Service's Geological Resources Division and geologists outisde the government who are experts in Great Lakes coastal dunes had not heard of anything like the dune collapse happening before.
Rowe said that once they have consulted with geologists at some other parks that have coastal sand dunes, they will study the dune with ground-sensing equipment. One test will look for anomalies below ground, and another test with ground penetrating radar will take a detailed look at any anomalies "to determine if they are holes or some other hazard."
It will be at least two weeks before a contract is in place for another agency or a private contractor to conduct the ground-sensing work, Rowe said.