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Plate Tectonics Study Guide (including earthquakes and volcanoes)
What is the theory of plate tectonics?
The theory that Earth’s crust is broken into large pieces
that move and interact
What was Pangea?
supercontinent consisting of all of Earth's land masses
What is the layer of the Earth that the plates move on?
Asthenosphere
What does the theory of continental drift state?
parts of the Earth's crust slowly drift atop a liquid core
Who came up the Continental Drift theory?
Alfred Wegener
Where are volcanoes likely to form?
Above subduction zones because of the ocean crust being
pushed down and eventually melting. This melted magma
finds its way up through fissures (cracks) in the Earth’s
surface.
Mantle (asthenosphere)
Where do convection currents take place?
Convection currents within the mantle drive plates to
move in different directions. The convection currents are
driven by the internal heat engine of the core. As the
mantle is heated, the hot less dense liquid rises and the
cool more dense liquid sinks creating movement within the
mantle.
What role do convection currents play in plate
tectonics?
As new oceanic crust is formed at mid-ocean ridges, new
land gradually moves away from the ridge.
Why does sea-floor spreading occur
What are 3 pieces of evidence for Seafloor spreading?
1. Molten Material - found rocks shaped like pillows, giving
evidence of quickly hardened molten material
2. Magnetic Reversals (stripes) - shows a change in the
Earth’s magnetic poles
3. Drilling Samples (the further away from the ridge a
sample was taken, the older the rock was)
What is paleomagnetism?
The study of Earth’s magnetic field
What is the main factor that determines what type of
collision occurs between 2 tectonic plates?
DENSITY!! (Ex. A pound of Lead is denser than a pound of
cotton)
Why do oceanic plates always subduct under the
continental plates?
Oceanic plates are more dense that continental plates.
What is the evidence that supports continental drift?
1.
Continents fit together like a puzzle
2. Distribution of climates do not match current climates.
3. Distribution of fossils seems unlikely.
4.
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Matching rock units and Mountain Belts
Scientists use earthquake waves to map the structure of
the inside of the earth. Different waves act differently as
they travel through different layers of the earth
Scientists know that the outer core is liquid because Swaves do not travel through liquids.
How do scientists know the inside of the earth is made
up of layers?
Identify:
1. Type of plate boundary
2. Direction of movement
3. Explain what land feature
has been created.
1.
Convergent boundary - continental to continental
2. Plates are colliding
3. Mountains are being formed
Identify:
1. Type of plate boundary
2. Direction of movement
3. Explain what land feature has
been created
1.
Divergent boundary - oceanic to oceanic
2. Plates are moving apart
3. Mid-ocean ridge has been formed
Identify:
1. Type of plate boundary
2. Direction of movement
3. Explain what land feature
has been created
1.
Identify:
1. Type of plate boundary
2. Direction of movement
1.
Explain what land feature
has been created
Identify:
1. Type of plate boundary
2. Direction of movement
3. A trench and island arc (under water volcano) have
formed.
2. Plates are colliding
3. A trench and volcano have formed
Converging oceanic to oceanic plates
2. Plates are colliding
1.
Transform boundary
2. Sliding past each other
3. Explain what happens at
this boundary.
1.
Converging boundary - oceanic to continental plate
Identify the type of fault.
2. Identify the type of stress
associated with this type of
fault
3.
Earthquakes are common.
1.
Normal Fault
2.
Stress = Tension
3. Divergent plate boundaries may cause normal faults
(tension).
3. Identify type of boundary that may cause this type
of fault.
2
1.
Identify the type of fault.
1.
2. Identify the type of stress
associated with this type of
fault
2. Stress = Compression
3. Convergent plate boundaries may cause reverse faults
3. Identify type of boundary that
may cause this type of fault.
1.
Reverse Fault
(compression).
Identify the type of fault.
1. Strike-slip Fault
2. Identify the type of stress
associated with this type of fault
2. Stress = Shearing
3. Identify type of boundary that may
cause this type of fault.
3. Transform plate boundaries may cause strike-slip
faults (shearing).
What is an earthquake?
Shaking that results from the movement of rock beneath
Earth’s surface
Where do most earthquakes occur?
Along all three types of plate boundaries (convergent,
divergent, transform)
What is the focus of an earthquake?
The point under Earth’s surface where rock breaks under
stress and causes the earthquake
What is the epicenter of an earthquake?
The point on earth’s surface directly above the focus
What is a seismic wave?
A vibration that travels through Earth carrying the energy
released during an earthquake
What do seismographs measure?
Records ground movements
Where does most of the damage from an earthquake
occur?
Near the epicenter
What is a volcano?
A weak spot in the crust where magma has come to the
surface
Which type of plate boundary does not typically include
volcanoes?
Transform
What is a hot spot?
An area where magma from deep within the mantle melts
through the crust above it
How did the Hawaiian Islands form?
Lava erupted from the hot spot and built a volcanic island.
The plate moved slowly and carried the island away from
the hot spot. Another volcanic island formed and was
carried away
What is an island arc?
Chain of volcanic islands that forms because of subduction
at a convergent boundary between two oceanic plates
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Describe a P-Wave
 Primary Wave (Compression Wave)
 Travels phastest so it arrives at a seismic stations
phirst
 Push-pull wave: rock vibrates forward and backward in
the same direction that the wave travels
 Pass through solids, liquids (magma), and gasses
Describe a S-Wave
 Secondary Wave- arrives at a seismic station second.
 Slow wave- not as fast as the P-wave.
 Shear Wave- vibrates side-to-side (right angles)
 Solids wave- only travels through Solids.
Fill in the chart.
Primary (Pwaves)
Travel through solids
x
Travel through liquids
x
Fastest waves
x
Secondary (Swaves)
Surface Waves (Lwaves)
x
x
Slowest waves
x
Cause most damage
x
Here’s some websites you can use to practice for this test:
http://www.quia.com/quiz/2017129.html (plate tectonics)
http://www.glencoe.com/qe/science.php?qi=278n (plate tectonics)
http://www.glencoe.com/qe/science.php?qi=274 (earthquakes)
Flashcards:
http://quizlet.com/31123017/plate-tectonics-flash-cards/
http://quizlet.com/31122674/earthquakes-flash-cards/
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