On July 2, 1937, Earhart, along with her co-pilot Fred Noonan, were en route to Howland Island where they had planned to take on fuel to continue their journey across the Pacific. Although their radio signals were heard by a nearby naval vessel, Earhart couldn't receive voice transmissions from the ship. As a result, she and Noonan were unable to locate the island and eventually ran of fuel, going down somewhere in the South Pacific.
Members of the The International Group for Historic Aircraft Recovery (TIGHAR) has long believed that Earhart was able to successfully land her plane on a coral reef near Nikumaroro and that she and Noonan survived as castaways for some time there. Artifacts discovered there led them to launch a search operation last summer that came away without any real solid evidence to support their theory however, but they did bring back a lot of data to sift through. The sonar readings were just a part of that data, which is now being examined throughly.
According to TIGHAR researchers, of all the sonar readings they took, none returned any useful information save this one. It purportedly shows a small debris field located at a depth of approximately 200 feet. The debris could be consistent with the parts of an aircraft that may have sunk and has slowly slid further down the reef. The debris ends at a larger object that is roughly 22-feet in length, or about the size of the Electra.
Further analysis of the readings indicate that the object is not a rock or other natural mass. It also lines up consistently with where it is believed that Earhart would have set the plane down on the reef. There are indications of drag marks on the reef itself, which show evidence of the object's movement over time.
Of course, the only way to be sure is to send another research team out to the island to investigate. That isn't an inexpensive proposition however and TIGAR estimates it will cost about $3 million to mount yet another journey to Nikumaroro. The non-profit group is currently looking to raise funds to do just that and they're hoping that some wealthy benefactor will want to see the mystery of Amelia Earhart solved as well.
Perhaps they should take their case to Kickstarter. I'm sure there are a number of history buffs like me who would be willing to contribute to the cause.