P-waves are a type of body wave, called
seismic waves in seismology, that travel through a
continuum and are the first waves from an earthquake to arrive at a seismograph. The
continuum is made up of
gases (as
sound waves), liquids, or solids, including the
Earth. P-waves can be produced by
earthquakes and recorded by
seismographs. The name P-wave can stand for either
pressure wave as it is formed from alternating
compressions and
rarefactions or
primary wave, as it has the highest velocity and is therefore the first wave to be recorded.