Who is the main subject in the memoir, Wave?

In her memoir Wave, Sonali Deraniyagala shares the true story of the tsunami in Sri Lanka that killed her husband, two sons, and parents. As the only one in her family who survived the wave, Deraniyagala fought through her grief and depression to find a new identity for herself. Her story covers a period of seven years as she tries to make sense of what happened and learn to deal with her grief.