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ch. 6 vocab. words
Question | Answer |
---|---|
plate | a large section of earth's crust and rigid upper-mantle that moves around on the asthenosphere. |
fault | surface along which rocks move when they pass their elastic limit and break. |
earthquake | vibrations produced which rocks break along fault. |
normal fault | break in rock caused by tension forces; rock above surface moves down to relative rock below that surface. |
reverse fault | break in rock caused by compressive forces; rock moves upward. |
strike-slip fault | break in rock caused by shear forces, rocks move past each other without much vertical movement |
wave | rhythmic movement that carries energy through matter and space |
seismic wave | wave generated by an earthquake |
focus | in an earthquake, the point below earth's surface where energy is released in the form of seismic waves |
primary wave | seismic wave that moves rock particles back and forth in the same direction that the wave travels |
secondary wave | seismic wave that moves rock particles at right angles |
surface wave | seismic wave that moves rock particles in a back and forth and side to side motion |
epicenter | point on earth's surface directly above an earthquake's focus |
seismograph | instrument used to register earthquake waves and record the time that each arrived |
crest | the highest point in a wave |
magnitude | measure of energy released during an earthquake |
liquefaction | occurs when soil acts more like a liquid during earthquakes |
tsunami | seismic sea waves that begin over an earthquake focus and can be highly destructive when it crashes on shore |