Earth Science Layers Quiz Flashcards
(27 cards)
How do we know about Earth’s interior?
We use seismic waves, density models, and meteorite evidence to learn about Earth’s structure because we can’t drill all the way to the center.
Seismic waves provide information on layer composition and state.
Why can’t we drill to Earth’s center?
It’s hard because of high temperatures and densities, and drilling like the Kola Superdeep Borehole only reached 12 km deep.
The Kola Superdeep Borehole is the deepest artificial point on Earth.
What are the three main layers of Earth?
Crust, mantle, and core.
What’s the difference between continental and oceanic crust?
Continental crust is thicker and less dense; oceanic crust is thinner and denser.
What are the three sub-layers of the mantle?
Rigid Mantle (solid), Plastic Mantle (slow flowing), Stiffer Mantle (solid but very hot and under pressure).
Describe the structure of the core.
Outer Core (liquid) and Inner Core (solid).
How does the movement in the outer core affect Earth?
The movement of liquid iron in the outer core creates Earth’s magnetic field.
What is the Lithosphere?
The Lithosphere includes the crust and rigid mantle.
What is the Asthenosphere?
The Asthenosphere is the plastic mantle, where material can flow slowly.
What is the Mohorovičić Discontinuity (Moho)?
The boundary between the crust and the rigid mantle.
What is an earthquake?
An earthquake is the sudden release of energy along faults in the lithosphere.
What causes an earthquake?
Stress and strain in Earth’s crust cause earthquakes. Stress is a force that pushes or pulls on the crust, and strain is the change in shape.
What is the Focus of an earthquake?
The Focus is the point underground where the earthquake starts.
What is the Epicenter of an earthquake?
The Epicenter is the point on the surface directly above the Focus.
What is the fastest seismic wave?
P-Waves are the fastest and move in a compression motion.
What is the slowest seismic wave?
Surface Waves are the slowest and cause the most surface damage.
How do P-waves and S-waves behave?
P-waves move through solids, liquids, and gases. S-waves only move through solids.
How do seismic waves behave at boundaries between layers?
Seismic waves refract, reflect, or absorb when they hit different layers.
What is the Shadow Zone?
The Shadow Zone is an area where no direct P-waves or S-waves are detected after an earthquake.
What caused the Shadow Zone?
S-waves are stopped by the liquid outer core, and P-waves refract sharply at different layers.
How did Inge Lehmann discover the solid inner core?
She used seismic data showing that P-waves refract on the solid inner core in the shadow zone.
How do seismic waves help us understand Earth’s interior?
Seismic waves can tell us whether layers are solid or liquid based on their speed.
What is a seismogram?
A seismogram is a printed recording of seismic waves.
What is refraction?
Refraction is the bending of seismic waves as they pass through different layers.
