Term | Definition |
Surface Wave | seismic wave that moves rock particles in a
backward, rolling motion and also in a side-to-side,
swaying motion |
Primary Wave | seismic wave that causes rock particles to
move back and forth in the same direction that the wave
is traveling |
Lithosphere | crust plus the rigid, upper mantle |
Seismic Wave | wave generated by an earthquake |
Focus | point below Earth’s surface where energy is first released in the form of seismic waves |
Secondary Wave | seismic wave that moves rock particles at
right angles to the direction of the wave |
Mercalli | scale used to measure the strength of an earthquake based upon damage. |
Earthquake | vibrations, or shaking, produced when rocks
break along a fault |
Epicenter | point on Earth’s surface directly above the
earthquake focus |
Seismograph | instrument used to register seismic waves
and record the time that each arrived |
Richter Scale | scale that compares the magnitude of an earthquake recorded by seismographs |
Core | solid inner most part of Earth's structure, made of solid iron-nickel |
Crust | rigid, rocky outer surface of Earth |
Mantle | rocky layer located under the crust. Composed of silicon, oxygen, magnesium, and calcium |
Mohorovicic Discontinuity | separates the crust and the upper mantle |
Asthenosphere | the part of upper mantle that is flowing |