Structure of the Earth the crust, upper mantle, lower mantle, outer core, and inner core. The geologic component layers of Earth are at the following depths below the surface: The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The core does not allow shear waves to pass through it, while the speed of travel (seismic velocity) is different in other layers. The changes in seismic velocity between different layers causes refraction owing to Snell's law, like light bending as it passes through a prism. Likewise, reflections are caused by a large
The Call of Earth The Call of Earth The Call of Earth (1992) is a science fiction novel by American writer Orson Scott Card. It the second book of the Homecoming Saga, a fictionalization of the first few hundred years recorded in the Book of Mormon. The book focuses on several key events that happen after Nafai, Elemak, Issib, Mebbekew, Zdorab and the father Volemak leave for the desert. Elemak has a dream from the Oversoul, foretelling Volemak's sons going back to the city of Basilica to get wives. The sons proceed to Nafai's and Issib's mother, Rasa, who is attempting to keep order