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science ch 21
ch. 21 vocab
word | definition |
---|---|
seismology | the study of earthquakes. |
fault | a break in the Earth's crust along which blocks of the crust slide past each other. |
potential energy | energy that an object has because of its position or shape. |
kinetic energy | the energy of motion. |
elastic rebound | the process by which rock that has been deformed by stress suddenly returns to its original shape. |
seismic waves | are waves of energy that travel through the earth, away from an earthwuake in all directions. |
p waves | travel through solids, liquids, and gases and are the fastest seismic wave. also the first primary wave. |
s waves | aka shear waves, are the 2nd-fastest seismaic wave. also is the 2nd seismic wave. secondary. |
surface waves | seismic waves that move the ground surface up and down in circles as they travel. |
seismographs | instruments that record seismic wavess and are located at or near the surface of the earth. |
seismogra | a tracing of ground motion created by a seismograph. |
epicenter | the point on Earth's surface directly above an earthquake's starting point. |
s-p time method | seismologists find an earthquake's epicenter . |
earthquake hazard level | a measure of how likely it is tahta an earthwuake will happen in a certain area. |
frequency | how often something happens. |
gap hypothesis | states that parts of active faults that have had relatively few earthquakes are places where strong earthquakes will happen in the future. |
seismic gaps | the parts of a fault where relatively few earthquakes have happened. |