A group of researchers at the Applied Research Laboratories (ARL) are cruising the Thunder Bay Maritime Sanctuary on Lake Huron, mapping the lake floor for undiscovered shipwrecks and a prehistoric archeological site.
They are deploying an ARL-developed sonar device, the Autonomous Topographic Large Area Survey (ATLAS) sonar, to gather high quality images of the lake bottom and the objects down there.
The survey is of the 448-square-mile Thunder Bay National Maritime Sanctuary, considered one of the nation's most historically significant collections of shipwrecks.
Thunder Bay is off the northeast side of Michigan's lower peninsula and is administered by the National Oceanic and Atmospheric Administration (NOAA).
The sanctuary contains 40 known shipwrecks, according to NOAA. Another 80 known sites are just outside the sanctuary's boundaries. Archival research indicates that as many as 100 sites still await discovery in northern Lake Huron.