Term
| What we know about the Earth’s Interior |
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Definition
comes from the study of seismic waves that
travel through the Earth |
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Term
| How Earthquakes (Seismic Waves) Reveal the Inside of the Earth |
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Definition
1. Velocity
2. Reflection and Refraction
3. Type of Wave |
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Term
| Velocity of Seismic Waves |
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Definition
| velocities of seismic waves increase when traveling through denser materials. |
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Term
| Density differences may be due to: |
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Definition
1.different compositions
2.changes in pressure and temperature
3.changes in physical state (solid vs. liquid) |
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Term
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Definition
| return of waves toward surface after encountering a boundary |
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Term
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Definition
| the bending / change in direction of a wave when it passes from one medium into another |
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Term
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Definition
1.P-waves transmitted through solids and liquids.
2.S-waves transmitted only through solids |
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Term
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Definition
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Term
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Definition
1.composed mostly of silicate rich igneous rocks.
2.Density increases with depth. |
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Term
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Definition
1.Oceanic crust
2.Continental crust
3.Moho |
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Term
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Definition
1.mostly basaltic rocks (slightly denser than continental crust)
2.thin
3.forms at mid-ocean ridges (divergent plate boundaries) |
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Term
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Definition
1.composition varies (less dense than oceanic crust)
2.thick |
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Term
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Definition
| boundary between crust and mantle |
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Term
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Definition
| crust and uppermost mantle |
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Term
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Definition
1.solid, composed of dense iron and magnesium silicate minerals.
2.Accounts for >82% of Earth’s volume
3.Layers of differing densities occur in the mantle as increasing pressure causes mineral structures to become more compact |
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Term
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Definition
1. Upper Mantle(100 km-660 km)
2. Lower Mantle(660km–core: 2900 km)
3. "D" Layer |
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Term
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Definition
1.Mantle lithosphere (moho–100 km)
2.Asthenosphere(100-410 km)–low velocity zone
3.Transition Zone (410-660) |
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Term
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Definition
1.bottom few hundred km
2.large horizontal variations in temperature and density
3.boundary with core is very uneven |
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Term
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Definition
| composed of dense metals (mostly iron and nickel) |
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Term
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Definition
1.Liquid outer core–S waves extinguished
2.solid inner core
3.Earth’s magnetic field is generated by circulation of the outer core |
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Term
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Definition
1.heat left over from collisions during planetary accretion
2.heat due to decay of radioactive isotopes
3.heat increases with depth (geothermal gradient) |
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Term
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Definition
| Conduction and Convection |
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Term
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Definition
| flow of heat through a material; only manner of heat transfer between Earth layers |
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Term
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Definition
| transfer of heat by circulation of material; cold sinks-hot rises |
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Term
| Where does convection occur? |
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Definition
1. in outer core (liquid)
2. in mantle (even though solid) |
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