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28 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Hypocenter
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below the earth, where rock ruptures and slips or the place where an explosion occurs
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epicenter
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point on the surface of the earth above the hypocenter
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Types of faults
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normal, reverse, thrust, strike slip, oblique slip
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normal fault
what causes it? |
hanging wall goes down relative to footwall (top block slides down)
due to crustal stretching |
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Thrust fault
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hanging wall goes up relative to footwall
due to crustal shortening slope or dip of the fault is not steep |
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Reverse fault
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hanging wall goes up relative to footwall
due to crustal shortening slop/dip of fault IS steep |
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strike-slip fault
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no vertical motion
one block slides laterally past the other fault surface is nearly vertical |
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oblique slip fault
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hanging wall slips diagonally
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tension/extensional fault
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fault will fall and hanging wall will fall down
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stress causes . . .
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faulting
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elastic-rebound theory
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during fault formation, fault elasticity strains then cracks
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types of seismic waves
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P-waves
S-waves Love waves Rayleigh waves |
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eq energy travels in . . .
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seismic waves
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P-waves
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compressional waves: particles of material move back and forth parallel to the direction in which the wave itself moves
like a slinky being pulled in and out |
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S-waves
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shear body waves: waves in which particles of material move back and forth perpendicular to the direction in which the wave itself moves
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like a slinky going up and down
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R-waves
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surface waves that cause the ground to ripple up and down
rocks churn along in circles |
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L-waves
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surface waves that cause the ground to ripple back and forth, like a snake
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seismograph- purpose
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records ground motion from an EQ happening anywhere on earth
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seismograph- how does it work?
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pen hanging from a spring hanging from a frame bolted to the ground, touches revolving cylinder of paper
pen traces out waves and creates a seismogram |
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Pattern of wave arrival in an EQ
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1. Fast moving p-waves (body)
2. S-waves (body) 3. Surface waves |
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Finding the epicenter
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P waves are faster than S waves
P-S waves = distance Delay b/t P and S waves increases as distance from epicenter increases |
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Travel-time curve
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line that charts time delay between P and S curves on a graph
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Triangulation
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3 stations allow this.
Around each station, draw a circle with the radius being the distance from the station to the epicenter. Epicenter lies at the intersection of the 3 circles |
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Richter Scale
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logorhythmic scale- small change in #'s, large change in intensity
measured from a seismogram |
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Mercalli Intensity Scale
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Impact to humans
Goes from 1-12, bigger numbers are bad |
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seimic activity occurs because of
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- the formation of a new fault
-slip on an existing fault -change in the arrangement of atoms of minerals -movement of magma in a volcano -explosion of a volcano -giant landslides -meteorite impact -underground nuclear bomb tests |
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earthquakes can include . . .
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ground shaking, sediment liquification, landslides, fire, tsunamis
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P-waves and S-waves start <blank> but <blank> moves <blank>
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P and S start at the same time but P-waves move faster
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