When the tsunami hit the eastern coast of Japan in 2011, it obliterated everything in its wake. The waves, some reaching as high as 133 feet, destroyed some 100,000 buildings and claimed the lives of over 15,000 residents. It's tough to conceive of human loss on that scale –  the mind tends to rebel against the thought of fifteen lives being swept away, let alone fifteen thousand. But Tokyo artist Munemasa Takahashi is trying to make those lives visible.

When the tsunami struck, it left behinds miles of detritus, discarding the personal belongings of residents up and down the coast. Some of those included thousands of cherished family snapshots that were ripped from their homes. In response, Takahashi was moved to join Salvage Memory, a nationwide rescue effort that sought to reunite these photos with their owners.

"Many people lost everything," Takahashi explains, "but they wanted to find their family photos, which can be the only one thing from the past, from the piles of thousands." 

This video shows the Salvage Memory team at work:

Over the last three years, Takahashi and the team of volunteers have discovered, cleaned up and digitised 750,000 photographs. So far, they've managed to return about 340,000 of them to their owners. But in some cases, the images would either be too badly damaged or their owners could proved untraceable. Takahashi compiled them into The Lost & Found Project, a photography exhibition that toured the world, including New York and LA. 

Those images are now collected in a new book called Tsunami, Photographs, and Then. It's a profoundly sobering reminder of those who lost their lives in the tragedy, and those whose fate we may never know. Japan may have recovered in the four years since the disaster, but as Takahashi puts it, "You can buy many new things with money, but could not buy photos you had taken in the past."

Tsunami, Photographs, and Then is out now from AKAAKA Publishing. You can find out more about the Lost & Found Project here, or purchase the book here.