HONOLULU » Even though a monthlong voyage for Amelia Earhart’s plane wreckage turned up no smoking gun, the searchers devoted to the hunt say they have a trove of evidence to go through that will help shed light on what happened to the famed aviator 75 years ago.

The expedition to a remote atoll roughly 2,000 miles southwest of Hawaii was well on its way back to Hono­lulu on Tuesday as Earhart’s family and others marked what would have been the American icon’s 115th birthday.

Google honored Earhart by changing the logo on its homepage, while her family said on their website that Earhart’s legacy remains relevant.

"The aviation pioneer, who was the first female pilot to cross the Atlantic Ocean, continues to make lasting impressions on people all over the world," the statement posted Tuesday said.

Pat Thrasher, president of The International Group for Historic Aircraft Recovery, said plans are already in the works for a land-based expedition to the Kiri­bati atoll of Niku­ma­roro next year.

The voyagers looked at footage as it initially came in from a tethered underwater vehicle rigged with cameras and lights. But the group expects to learn more through repeat viewings, picking up new insights on the underwater landscape where they believe the plane went down. The group has countless hours of high-definition video and sonar data.

"It’s unbelievably difficult as an environment, and your eyeballs fall out after a while" watching the video, Thrasher said. "The only way you can be sure you know what you found is to go back through the data very carefully."

The expedition cost $2.2 million. The group was short nearly $500,000 at the start of the voyage and will need to raise more funds for any future trips.

But the group still believes Earhart and her navigator crashed onto a reef off the remote island, Thrasher said.

Remnants of the plane, the group believes, could be in hard-to-see caves within a reef that drops like a cliff thousands of feet underwater. Or, it might have simply floated away to another area that’s impossible to predict.

"This is just sort of the way things are in this world," Thrasher said. "It’s not like an Indiana Jones flick where you go through a door and there it is. It’s not like that — it’s never like that."

Thrasher maintained touch throughout the search with the group’s founder Ric Gillespie, her husband, and posted updates about the trip to the group’s website. The updates tell of a search that was cut short because of treacherous underwater terrain and repeated, unexpected equipment mishaps that caused delays and left the group with only five days of search time rather than 10, as originally planned.

The U.S. State Department had encouraged the privately funded voyage, which launched earlier this month from Hono­lulu using 30,000 pounds in specialized equipment and a University of Hawaii ship normally used for ocean research.

The group’s thesis is based on the idea that Earhart and navigator Fred Noonan landed on a reef near Niku­ma­roro, then survived a short time.

Previous visits to the island have recovered artifacts that could have belonged to Earhart and Noonan, and experts say an October 1937 photo of the shoreline of the island could include a blurry image of the strut and wheel of a Lockheed Electra landing gear.