RIKUZENTAKATA, Japan -- The healing continues, more than four years after a magnitude-nine earthquake triggered a massive tsunami that devastated Japan, killing more than 15,000.

Ten hours a day, six days a week, rock is funneled through nearly two miles of giant conveyor belts. It'll form a new foundation for an entire town.

Amya Miller is an American who grew up in Japan. She was so devastated by news of the tsunami that she flew to Japan to volunteer -- and never left.

Now she's helping the government of Rikuzentakata, which lost a tenth of its population -- more than 1,700 people -- when the town washed away.

Crews are working to lift the city three stories higher by shaving off the top of a mountain and redepositing the soil.

Construction crews work to raise the city CBS News

"We are rebuilding the city literally from the ground up," said Miller. "We are moving mountains. I can't get much more literal than this."

From above, we saw the $1.5 billion project. Conveyor belts move 4,000 dump-truck loads of soil every day.

Tsuyoshi Yamada is in charge.

Pub owner Eiki Kumagai CBS News

"Usable land is extremely scarce through the disaster zone but especially here," he told us. "There is nowhere else for us to rebuild."

Pub owner Eiki Kumagai is still living in temporary housing. His restaurant -- on the outskirts of town -- is temporary, too.

"For me, moving somewhere else is not an option," said Kumagai. "My family has lived here for generations."

Survivors here say they must rebuild on this spot, or be defeated by the tsunami.