P wave

This article is on the type of seismic wave. For the term used in electrocardiography, see P wave (electrocardiography). P wave can also refer to a type of electronic wave function in atomic physics; see atomic orbital.

Plane P wave

Representation of the propagation of a P wave on a 2D grid (empirical shape)

In continuum mechanics, a P wave (primary wave or pressure wave) is one of the two main types of elastic body waves or seismic waves. P waves travel faster than other seismic waves and hence are the first signal from an earthquake to arrive at any affected location or at a seismograph. P waves may be transmitted through gases, liquids, or solids.