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50 Cards in this Set
- Front
- Back
What is Stress? |
a force that acts on rock and causes changes in the rocks shape or volume
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What creates Stress? |
movement of Earths plates |
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Many rocks can ________ or ________, but beyond a certain limit they will eventually _______. |
bend, fold, break |
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what is tension? |
a stress that pulls on the crust causing the rock to become thinner in the middle |
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where does tension occur? |
where land is spreading apart |
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what is compression? |
a stress that squeezes rock util it breaks or folds |
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where does compression occur? |
when land is pushed together |
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what is shearing? |
a stress that pushes rock in 2 opposite directions causing it to bend of break sideways |
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where does shearing occur? |
where land is slipping horizontally |
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what causes a normal fault? |
tension |
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Is a normal fault at an angle? |
yes |
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What does the hanging wall do in a normal fault? |
the hanging wall slips down the footwall |
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A normal fault crust _______ ( or ______ ________) |
diverges, pulls apart |
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What causes a reverse fault? |
compression |
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Is a reverse fault at an angle? |
yes |
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What does the reverse fault hanging wall do? |
the hanging wall slides up the footwall |
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What causes a strike-slip fault? |
shearing (sideways stress) |
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In strike-slip faults rocks on either side ______ past each other _______________ |
slip, horizontally |
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Why do earthquakes occur? |
fault surfaces experience high friction |
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What is friction? |
the force that resists the motion of one surface as it moves across another surface |
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What kind of surfaces have low friction? |
two slippery surfaces |
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What kind of surfaces have high friction? |
two rough surfaces |
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What is the focus point? |
the point beneath the Earth's surface where the earthquake begins |
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What is the epicenter? |
the point on the surface directly above the focus |
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What are seismic waves? |
vibrations that travel through Earth's interior and across the surface |
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Seismic waves carry the earthquakes.... |
energy away from the focus in all directions |
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What are the three main categories of seismic waves? |
P-waves, S-waves, and surface waves |
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What type of wave is first to arrive? |
P-waves |
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What type of wave arrives second? |
S-waves |
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What type of wave arrives last? |
Surface waves |
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What is another name for P-waves |
primary waves |
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What is another name for S-waves |
secondary waves |
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How does the ground move with p-waves? |
the ground is compressed and expanded (push-pull) |
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What do p-waves travel through? |
solids and liquids |
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In what way do s-waves vibrate? |
side to side, up and down |
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What do s-waves travel through? |
solids |
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What wave is the most severe? |
surface waves |
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What motion do surface waves travel? |
side to side, circular |
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What does shaking trigger? |
landslides or avalanches |
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What 5 things can shaking damage? |
buildings, bridges, utility poles, gas pipes, water pipes |
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What shakes more violently loose soil or solid rock? |
loose soil |
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What can cause a fire? |
broken gas lines and broken power lines |
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Is it a problem when the water line that feed the fire hydrants break? |
yes |
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When does liquefaction occur? |
when an earthquakes shaking turns loose soft soil into liquid mud |
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Where is liquefaction most likely to occur? |
where the soil is full of moisture |
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What are aftershocks? |
earthquakes that occur after a larger quake in the same area |
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What can after shocks cause? |
the collapse of buildings that were weakened in the original quake |
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What are tsunamis? |
large waves created by uplift of the ocean floor |
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What happens to the wave height when it approaches shallow water? |
it becomes a mountain of water |
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Where is the tsunamis wave low? |
in the open ocean |