Escape From the Great Earthquake by Kate Messner

This time Ranger, the time-traveling Golden retriever, finds himself in San Francisco in the middle of the great 1906 earthquake, and his mission is obviously to get a young Chinese immigrant, Lily Chen, to safety, but as they make their way through the ruined and burning city Ranger finds that he must also accomplish something else--finding Lily, who was sold as a servant by her parents, a new family who will care for her.