Unit 1 Earth: Note 4 Plate Tectonics, Earth's Interior & Crust

  1. Evidence for Earth’s Structure: Earth’s compositions, Earth Internal Structure, Density & Waves, Rock density & temperature

  2. Earth’s Layers: Crust, Mantle, Outer Core, Core

  3. Earth’s Composition: samples of Earth’s surface that gives clues to Earth’s composition.

  4. Volcanoes: bring up lava and harden on the surface of the Earth, bring samples of composition

  5. Tectonics: tectonic shifting can bring up samples of composition

  6. Meteorites: compositions match planetory interior

  7. Earth’s Internal Structure: seismic waves from earthquakes help us measure and determine the earth’s interior. Measure the depth of layer boundaries, thickness of layers, characteristics of different layers

  8. S, P, and L, Waves: waves triggered by earthquakes, or tectonic movements, that can be measured to understand the earth’s structure

  9. P wave: primary wave, is a compression wave that has the most velocity. Can propagate through solids AND liquids ie. the earth’s crust, mantle, outer core, core

  10. S wave: secondary wave, is a shear wave, that has a lesser velocity. Only propagates through solids, not liquids. Can go through, crust, mantle, skip the outer core, then core. They radiate 180 degrees from eq. site, so cannot be detected on the opposite side of the earth, evidence that there is a liquid layer on the interior of the Earth

  11. P waves: refract and bend, go in an outward then bent motion as they travel. Have two small mirrored shadow zones

  12. Density of waves: seismic waves reflect and refract as they travel through rock of different densities. Seismic waves bend as they refract through the crust, and reflect through the asthenosphere. Shows the boundaries and densities of layers

  13. Crust: is made of continental and oceanic. Continental is thicker, flexible, older and less dense. Oceanic is thinner, brittle, and more dense, and younger

  14. Mantle: solid but moves under pressure (convection, tectonic plate subduction), very dense

  15. Outer Core: molten liquid, no S waves, contains earth’s magnetic field

  16. Inner Core: solid, made of iron

  17. Asthenosphere: interior layer that can move or flow (in mantle)

  18. Margins