"La metodologia sismica a rifrazione utilizza le onde compressive."

www.cis-geofisica.it/html/sismica_a_rifrazione.html

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Note added at 2003-05-16 16:03:15 (GMT)
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Sorry, wrong language!

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Note added at 2003-05-16 16:04:38 (GMT)
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COMPRESSIVE is OK in English too - sorry about the Italian reference. I\'ll look for some English ones for you, Sandy.



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Note added at 2003-05-16 16:06:29 (GMT)
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\"Motion of a building as two seismic pulses enter the basement ... waves and surface waves tend to be more dangerous for buildings than compressive waves. \"

www.mines.utah.edu/~schuster/gg103/res/resonance.html


\"There are three types of seismic waves: the first two are called body waves because they pass through the body of the Earth.

1. P-waves or Primary waves: these are a type of compressive wave (it disturbs the Earth in a push-pull motion). These move the fastest. Compressive waves can move through solids and liquids.

2. S-waves or Shear waves (also called secondary waves): these are type of shear wave (it disturbs the Earth as a wave). These move more slowly than P-waves. They can move through solids, but not through liquids.

3. Surface waves: these pass over the surface of the Earth and move more slowly than either of the body waves.\"

http://www-class.unl.edu/geol109/earthstructure.htm