# Dictionary:P-wave

Series | Geophysical Reference Series |
---|---|

Author | Robert E. Sheriff |

DOI | http://dx.doi.org/10.1190/1.9781560802969 |

ISBN | 978-1-56080-118-4 |

Store | SEG Online Store |

An elastic body wave in which particle motion is in the direction of propagation. The type of seismic wave assumed in conventional seismic exploration. Also called **primary wave** (undae primae), **compressional wave**, **longitudinal wave**, **push-pull wave**, **pressure wave**, **dilatational wave**, **rarefaction wave**, and **irrotational wave**. In an isotropic homogeneous solid, the P-wave velocity *V*_{P} can be expressed in terms of the elastic constants and the density (ρ):

where λ and μ are the Lamé constants, *E* is Young’s modulus, *K* is the bulk modulus, and σ is Poisson’s ratio. See also *wave notation* and Sheriff and Geldart (1995, 44–45)^{[1]}.

## References

- ↑ Sheriff, R. E. and Geldart, L. P., 1995, Exploration Seismology, 2nd Ed., Cambridge Univ. Press.