The Big Wave by Pearl S. Buck

Two friends, Kino and Jiya live in Japan. Kino's family farm the land on the side of a mountain. His best friend Jiya lives on the beach below where he fishes with his father. Kino fears the Volcano on his mountain and Jiya fears the sea might become angry. One day the bell at the castle begins to ring. Kino and his family rush outside. His father tells him this has happened once before and that the villagers below need to go to the castle. Kino sees several families or their children run to the castle. He waves to his friend Jiya. Jiya runs to the house of his friend Kino. There they watch as a giant wave wipes out all of the village and remaining people below, including Jiya's family. Given the choice to live with the old man in the castle or with his best friend's family, Jiya chooses his best friend's family. As time passes people begin to build on the beach again. Kino misses the beach and must make several decisions that not only affect him but the young girl he wants to marry.