ENVS 1060 Lecture Notes - Lecture 2: Seismic Wave, Oceanic Crust, Ground Vibrations
3 Feb 2018
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Earths internal layers: crust, mantle, outer core, inner core. From direct observation of rocks that have come up. The average density of the earth is much heavier than the average density of rocks on the surface of the earth. Something within the earth had to be very different to account for the earths high density. The common things that we know to be heavy are metals. Earthquakes and man-made events (like the atomic bomb) generate energy waves called seismic waves that travel throughout the earth. We use these to study the internal structure of earth. All seismic waves travel faster as density of the medium increases: denser material transmits energy faster. When seismic waves encounter a change in material (either density or phase solid or liquid), some of that energy is reflect back to the surface and some of that energy is transmitted downwards through refraction.
