(See related pages)
Below you will find key words and concepts that you should remember from this chapter.
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| asthenosphere | A region of Earth’s outer shell beneath the lithosphere. The asthenosphere is of indeterminate thickness and behaves plastically. (See page(s) 418) |
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| convection | A very slow circulation of a substance driven by differences in temperature and density within that substance. (See page(s) 423) |
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| core | The central zone of Earth. (See page(s) 417) |
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| crust | The outer layer of rock, forming a thin skin over Earth’s surface. (See page(s) 416) |
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| crustal rebound | The rise of Earth’s crust after the removal of glacial ice. (See page(s) 424) |
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| Curie point | The temperature below which a material becomes magnetized. (See page(s) 429) |
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| geophysics | The application of physical laws and principles to a study of Earth. (See page(s) 414) |
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| geothermal gradient | Rate of temperature increase associated with increasing depth beneath the surface of Earth (normally about 25°C/km). (See page(s) 433) |
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| gravity meter | An instrument that measures the gravitational attraction between Earth and a mass within the instrument. (See page(s) 426) |
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| heat flow | Gradual loss of heat (per unit of surface area) from Earth’s interior out into space. (See page(s) 434) |
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| isostasy | The balance or equilibrium between adjacent blocks of crust resting on a plastic mantle. (See page(s) 424) |
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| isostatic adjustment | Concept of vertical movement of sections of Earth’s crust to achieve balance or equilibrium. (See page(s) 424) |
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| lithosphere | The rigid outer shell of Earth, 70 to 125 or more kilometers thick. (See page(s) 418) |
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| magnetic field | Region of magnetic force that surrounds Earth. (See page(s) 428) |
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| magnetic pole | An area where the strength of the magnetic field is greatest and where the magnetic lines of force appear to leave or enter Earth. (See page(s) 428) |
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| magnetic reversal | A change in Earth’s magnetic field between normal polarity and reversed polarity. In normal polarity the north magnetic pole, where magnetic lines of force enter Earth, lies near the geographic North Pole. In reversed polarity the south magnetic pole, where lines of force leave Earth, lies near the geographic North Pole (the magnetic poles have exchanged positions). (See page(s) 429) |
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| magnetometer | An instrument that measures the strength of Earth’s magnetic field. (See page(s) 432) |
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| mantle | A thick shell of rock that separates Earth’s crust above from the core below. (See page(s) 417) |
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| Mohorovicˇic´ discontinuity (Moho) | The boundary separating the crust from the mantle beneath it (also called Moho). (See page(s) 418) |
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| negative gravity anomaly | Less than normal gravitational attraction. (See page(s) 428) |
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| negative magnetic anomaly | Less than average strength of Earth’s magnetic field. (See page(s) 433) |
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| paleomagnetism | A study of ancient magnetic fields. (See page(s) 429) |
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| positive gravity anomaly | Greater than normal gravitational attraction. (See page(s) 427) |
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| positive magnetic anomaly | Greater than average strength of the earth’s magnetic field. (See page(s) 433) |
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| P-wave shadow zone | The region on Earth’s surface, 103° to 142° away from an earthquake epicenter, in which P waves from the earthquake are absent. (See page(s) 421) |
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| seismic reflection | The return of part of the energy of seismic waves to Earth’s surface after the waves bounce off a rock boundary. (See page(s) 414) |
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| seismic refraction | The bending of seismic waves as they pass from one material to another. (See page(s) 414) |
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| S-wave shadow zone | The region on Earth’s surface (at any distance more than 103° from an earthquake epicenter) in which S waves from the earthquake are absent. (See page(s) 421) |