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Earthquake Preview13
Earthquakes
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Earthquake Preview13
Explain the geological forces scientists believe cause the tectonic plates
to move.
Scientists believe convection currents in the mantle are responsible for
tectonic plate movement. As the magma is heated in the mantle
(asthenosphere) it becomes less dense and rises toward the surface
contacting the land above (bottom of the lithosphere). The magma is
pushed along the bottom of the lithosphere by more material rising
behind it. The magma catches on the lithosphere and pushes on it
creating plate movement. As the magma cools it becomes more dense
sinking back into the mantle allowing the convection currents to
continue again and again.
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Reverse Fault
Normal Fault
Strike-Slip Fault
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Name that fault!
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Force type?
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Name that fault!
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Force type?
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Name that fault!
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Force type?
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True
False
S-waves can travel through solids and liquids.
There are four waves that are associated with
earthquakes.
If the P, S and surface waves arrive almost
simultaneously, the seismic recording station is close to
the epicenter of the earthquake.
By noting the change in the speed and the reflection point
of seismic waves, scientists have been able to determine
the structure of the Earth's interior.
Earthquake Preview13
True
False
P-waves can travel through solids and liquids.
Unconsolidated, water-saturated soils or sediments
provide good foundation material for buildings and other
structures.
Earthquakes only happen West of the Rocky Mountains.
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Name that wave!
Least destructive wave.
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Name that wave!
Second wave to
reach you in an
earthquake.
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Name that wave!
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Name that wave!
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Most earthquakes occur along ____.
A. volcanoes
B. faults
C. rivers
Seismic waves move outward from the ___ which is usually deep
underground.
A. epicenter
B. focus
C. city
What are the smaller magnitude quakes that follow a major earthquake?
A. exoshocks
B. epishocks C. aftershocks
At least ___seismograph stations are needed to locate the epicenter of an
earthquake.
A.2
B.3
C.4
S-waves do not travel through the outer core because it is __.
A. a liquid
B. a solid
C. plastic-like
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Most of the destruction during an earthquake is caused by (surface
waves, secondary waves).
Seismologists use the (seismograph, Richter Scale) to compare the
magnitude of earthquakes.
The slowest seismic waves are (primary waves, surface waves).
Primary waves arrive at a seismograph station (first, second).
Scientists use the triangulation method to locate an earthquake's
(epicenter, focus).
When the buildup of stress in Earth's crust is so great that rocks reach
their (elastic limit, tectonic force), an earthquake occurs.
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Write the correct letter in front of the proper fault name.
Strike-slip fault
Normal fault
Reverse fault
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Normal Fault
Reverse Fault
Rocks above the fault surface move downward in
relation to rocks below the fault surface.
This kind of fault occurs at divergent plate boundaries.
Tension pulls rocks apart.
The Himalaya Mountains contain many of these faults.
Rocks above the fault surface are forced up and over the
rocks below the fault surface.
This kind of fault occurs at convergent plate boundaries.
Compression pushes rocks in.
The San Andreas Fault is an example of this kind of fault.
Strike-slip Fault
Rocks on either side of the fault boundary move past each other
without much upward or downward movement.
Shearing forces push rocks from different, but
not opposite, directions.
This kind of fault occurs at transform fault boundaries.
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Earthquakes
An earthquake is any violent shaking or
rapid motion of the earth's surface.
Pick a number and name the earthquake feature:
Epicenter - Location on surface above Focus
Focus - Location along fault where earthquake
occurs
3
1
2
Fault - Large break in Earths Crust where
movement occurs
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Earthquake Waves
P-Waves
Travel by Pushing and Pulling
the earth.
Very Fast
S-Waves
Travel by moving earth
side to side
Slower than P-waves
shear wave
Causes most damage
First wave to arrive
2nd wave to arrive
Pwaves can travel through the core
Swaves CANNOT travel through the CORE
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Determine Distance to Epicenter
1. Subtract Travel Times to find
the difference in Travel Times.
2. Find the point on the table
where the waves are separated by
that amount of time.
3. Follow that point down to the
distance.
4. That is the distance to the epicenter
P-wave travel time
time difference
S-wave travel time
Distance to
the Epicenter
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Earthquake Shadow Zone:
Area on earth that does not recieve any waves from a PARTICULAR
earthquake.