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Earthquakes occur when one mass of rock suddenly moves against another, releasing a
huge amount of energy in the form of seismic waves. These
waves take a number of forms, but the two most important are known as 'P'
and 'S' waves. The table below describes the nature of each.
| Wave |
Nature |
Speed |
| P-wave
|
Primary (also Pressure
or Push-Pull) wave that travels through the Earth as a
longitudinal wave. |
6 km s-1 |
| S-wave
|
Secondary (or Shear)
wave that travels through the Earth as a transverse wave. |
3.5 km s-1 |
Explore further...
If you'd like to explore a little the differences between longitudinal waves and
transverse waves, then click here.
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