Paint the Wind by Pam Munoz Ryan

Maya is unhappy living with her grandmother after a tragic accident takes the lives of her parents. Grandmother does not let Maya participate in any activities outside her home except school. When her grandmother passes away unexpectedly, Maya moves to Wyoming to live with her mother's family. There, Maya learns to ride a horse and begins to bloom. One day while trying to get closer to a wild Paint horse that her aunt named Artemesia, Maya gets caught in the middle of an earthquake. She manages to survive on her own for a week before Artemesia carries her back to her camp.