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23 terms

Earth Science Chapter 8 Vocabulary

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earthquake
the vibration of Earth produced by the rapid release of energy
focus
the point within Earth where an earthquake originates
epicenter
the location on Earth's surface directly above the focus, or origin, of an earthquake
fault
a fracture in Earth along which movement has occurred
elastic rebound hypothesis
the explanation stating that when rocks are deformed, they break, releasing the stored energy that results in the vibrations of an earthquake
aftershock
a small earthquake that follows the main earthquake
foreshock
a small earthquake that often precedes a major earthquake
seismograph
an instrument that records earthquake waves
seismogram
the record made by a seismograph
surface wave
a seismic wave that travels along the surface of Earth
P wave
earthquake wave that pushes and pulls rocks in the direction of the wave; also known as a compression wave
S wave
a seismic wave that shakes particles perpendicular to the direction the wave is traveling
moment magnitude
a more precise measure of earthquake magnitude than the Richter
liquefaction
a phenomenon, sometimes associated with earthquakes, in which soils and other unconsolidated materials saturated with water are turned into a liquid that is not able to support buildings
tsunami
the Japanese word for a seismic sea wave
seismic gap
an area along a fault where there has not been any earthquake activity for a long period of time
crust
the thin, rocky outer layer of Earth
mantle
the 2890-kilometer-thick layer of Earth located below the crust
lithosphere
the rigid outer layer of Earth including the crust and upper mantle
asthenosphere
a weak plastic layer of the mantle situated below the lithosphere; The rock within this zone is easily deformed
outer core
a layer beneath the mantle about 2260 kilometers thick
inner core
the solid innermost layer of Earth, about 1220 kilometers in radius
Moho
the boundary separating the crust from the mantle, discernible by an increase in the velocity of seismic waves