EESA06H3 Chapter Notes - Chapter 4: Cosmic Ray, Magnetometer, Paleomagnetism
Document Summary
Geophysics: application of physical laws and principles to a study of the earth. Study of seismic waves and earth"s magnetic field, gravity, and heat. Seismic reflection: return of some of the energy of seismic waves to the earth"s surface after the waves bounce off a rock boundary. Shows amount of time waves took to travel to the boundary, reflect and return to surface. Seismic refraction: bending of seismic waves as they pass from one material to another. Similar to the way that light waves bend when they pass through the lenses of eyeglasses. Much of seismic wave energy passes across the boundary. Changes direction as crosses from one rock layer to another. Occurs only if the velocity of seismic waves is different in each layer. Generally true if the rock layers differ in density or strength. Increasing pressure with depth tends to increase velocity. Crust: outer layer of rock, which forms a thin skin on earth"s surface.
