Ch. 16. Plate Tectonics. Layers of the Earth. Thickness: 5 – 40 km Composition: Oxygen, Silicon, Aluminum, Calcium, Iron, Sodium, Potassium, Magnesium Temperature: Up to 1,600 degrees F. Crust. Thickness: 2,900 km
Rocks on one side of a fault can move up, down, or sideways in relation to the rocks around them.
Rock on one side of a fault can move over, under, or past each other along fault lines.Earthquake - vibrations produced by breaking rock.
Focus - an earthquake’s point of energy release.Seismic waves
A seismic wave’s speed and direction change as the wave moves through different layers with changes in densities.
Generally increases with depth as pressure increases.
Most earthquakes are of a magnitude too low to be felt by humans - 3.0 to 4.9 on the scale.