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23 Cards in this Set
- Front
- Back
faults
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what rocks move along when they break
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elastic deformation
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applied forces cause rocks to undergo_______________
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elastic limits
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rock break when their _____________ are passed
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earthquake
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vibrations produced by breaking rock
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normal fault
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caused by rock above the fault moving downward in relation to the rock below the fault - tension forces
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reverse fault
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compression forces squeeze rock above the fault up and over the rock below the fault
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strike-slip
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fault created by shear forces; rocks on either side of the fault move past each other without much upward or downward motion
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seismic waves
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waves generated by an earthquake; can move the ground forward and backward and up and down and side to side
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focus
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an earthquake's point of energy release
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primary waves
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p-waves; cause particles to move back and forth in the same direction as the wave is traveling; move the fastest of the waves
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secondary waves
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s-waves; cause particles to move at right angles to the direction as the wave is traveling; move second fastest of the waves
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surface waves
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move rock particles in a backward rolling motion and sideways swaying motion; move slowest
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epicenter
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the point on Earth's surface directly above the earthquake focus
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seismograph
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measures seismic waves; consists of a rotating drum of paper and a pendulum with an attached pen
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seismogram
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the paper record of a seismic event
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crust
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Earth's outermost layer; about 5 to 60 km thick
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shadow zones
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do not receive seismic waves because the waves are bent or stopped by material of different density
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seismologists
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scientists who study earthquakes
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magnitude
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measure of energy released by an earthquake; determined by the Richter scale and based on the height of the lines on a seismogram
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Mercalli scale
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a modified intensity scale that describes earthquake intensity based on structural and geologic damage
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liquefaction
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shaking from an earthquake can make wet soil act like a liquid
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tsunamis
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ocean waves caused by earthquakes; caused when a sudden movement of the ocean floor pushes against the water; can travel thousands of km in all directions
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moorings
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made of alternating layers of rubber and steel; flexible; circular; placed under buildings to withstand seismic vibrations
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