1. Geology Notes
Part 5

2. What are the compositional layers of Earth?
The layers inside the earth that are separated by the materials in each layer.
The layers are the Crust, Mantle, and Core. 2

3. What are the structural layers of Earth?
The layers inside the Earth that are separated by their physical structure.
The lithosphere is solid
The athenosphere is a solid that flows
the mesosphere is a rigid solid
The Outer Core is liquid
The Inner Core is solid 3

4. Where is the magnetic field of the Earth generated?
It may be the liquid iron in Earth’s outer core
motions within the core produce electric currents that in turn create Earth’s magnetic field. 4

5. What are Seismic waves?
Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion.
They are the energy that travels through the earth and is recorded on seismographs.

6. What are Seismic waves?
The two main types of waves are body waves and surface waves.
Body waves can travel through the earth's inner layers,
but surface waves can only move along the surface of the planet like ripples on water.

7. What is the difference between P and S waves?
P-Waves
Primary (they arrive first), Pressure, or Push-Pull. Material expands and contracts in volume and particles move back and forth in the path of the wave. P-waves are essentially sound waves and travel through solids, liquids or gases.

8. What is the difference between P and S waves?
Secondary (arrive later), Shear, or Side-to-side. Material does not change volume but shears out of shape and snaps back. Particle motion is at right angles to the path of the wave. Since the material has to be able to "remember" its shape, S-waves travel only through solids.

9. What is the difference between P and S waves?

10. How can seismic waves be used to identify the properties of Earth’s interior?
By recording seismic waves around the world shadow zones are revealed due to the inability of S waves to travel through liquids.
Seismic waves also bend (refract) when they pass through different materials .
By measuring the speed, strength, and changes in the seismic waves Earth’s interior has been calculated

11. Describe the difference between oceanic and continental crust
Oceanic crust is younger, more dense, and made up of mainly heavier rocks like basalt.
Continental crust is older, less dense and made of mostly lighter rocks like granite.