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Chapter 12 Vocab

Holt McDouglal Earth Science 2010
STUDY
PLAY
earthquake
a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move
elastic rebound
the sudden return of elastically deformed rock to its undeformed shape
focus
the location within Earth along a fault at which the first motion of an earthquake occurs
epicenter
the point on Earth's surface directly above an earthquake's starting point, or focus
body wave
in geology, a seismic wave that travels through the body of a medium
surface wave
in geology, a seismic wave that travels along the surface of a medium and that has a stronger effect near the surface of the medium than it has in the interior
P wave
a primary wave, or compression wave; a seismic wave that causes particles of rock to move in a back-and-forth direction parallel to the direction in which the wave is traveling; P waves are the fastest seismic waves and can travel through solids, liquids,
S wave
a secondary wave, or shear wave; a seismic wave that causes particles of rock to move in a side-to-side direction perpendicular to the direction in which the wave is traveling; S waves are the second-fastest seismic waves and can travel only through solid
shadow zone
an area on Earth's surface where no direct seismic waves from a particular earthquake can be detected
fault zone
a region of numerous, closely spaced faults
seismograph
an instrument that records vibrations in the ground
seismogram
a tracing of earthquake motion that is recorded by a seismograph
magnitude
a measure of the strength of an earthquake
intensity
in Earth science, the amount of damage caused by an earthquake
tsunami
a giant ocean wave that forms after a volcanic eruption, submarine earthquake, or landslide
seismic gap
an area along a fault where relatively few earthquakes have occurred recently but where strong earthquakes are known to have occurred in the past