Plate Power
Who proposed the idea of continental drift?
Alfred Wegener.
What does the word “Pangea” mean in Greek?
“All Earth.”
What is an earthquake?
The shaking of Earth's crust caused by sudden movement of plates.
What device records seismic waves?
A seismograph.
What is seismic shaking?
Shaking of the ground due to seismic waves.
What does the modern theory of plate tectonics state?
Earth’s lithosphere is broken into plates that move because of mantle convection.
What is one piece of evidence that supports Pangea based on the shape of continents?
Continents like South America and Africa fit together like puzzle pieces.
What is the focus of an earthquake?
The point underground where the rock breaks.
What is the difference between P-waves and S-waves?
P-waves are faster and travel through solids & liquids; S-waves are slower and travel only through solids.
What is liquefaction and why is it dangerous?
Water-soaked soil behaves like a liquid, causing buildings to sink.
Describe what happens at a convergent boundary between an oceanic and continental plate.
The denser oceanic plate subducts beneath the continental plate, forming a trench and volcanic arc.
Imagine you discover a new fossil of a land-dwelling animal on both Australia and Antarctica. Use the idea of Pangea to explain how this is possible.
The continents were once connected, so animals could move freely between them before the plates drifted apart.
Explain elastic rebound.
Stress builds in rocks until they snap and release stored energy as an earthquake.
What’s the difference between the Richter Scale and the Moment Magnitude Scale?
Richter measures wave size; Moment Magnitude measures total energy released (more accurate).
What triggers landslides during an earthquake?
Shaking loosens rocks and soil on steep slopes.
What process creates new ocean floor at mid-ocean ridges?
Sea-floor spreading.
How do glacial scratches found in warm places like Africa and India support the idea of continental drift?
The scratches show those continents were once located closer to the South Pole, where glaciers could form.
What’s the difference between foreshocks and aftershocks?
Foreshocks occur before the main earthquake; aftershocks occur after.
What is the largest magnitude earthquake ever? Where did it occur?
A 9.5 on the Richter Scale in Chile.
During a massive earthquake, which hazard (liquefaction, shaking, landslides, tsunami) would be most dangerous near a coastline? Explain.
Tsunami—can flood entire coastal areas and cause widespread destruction.
In the graham cracker lab, what real-earth process did pushing one cracker under the other represent?
Subduction at a convergent boundary.
When given a broken map of Pangea, what clues help you put the continents together?
Coastline shapes, fossil locations, and matching rock types.
Give one key fact about the San Andreas Fault from class.
It is a transform boundary where the Pacific Plate and North American Plate slide past each other.
Compare body waves and surface waves.
Body waves travel through Earth’s interior; surface waves travel along the surface and cause more damage.
Why might a magnitude 6.0 earthquake in one location cause far more damage than a magnitude 7.0 earthquake somewhere else?
Depends on soil type, building design, population density, and proximity to the epicenter—not just magnitude.