# Dictionary:P-wave

Other languages:
English • ‎español

Series Geophysical Reference Series Robert E. Sheriff http://dx.doi.org/10.1190/1.9781560802969 978-1-56080-118-4 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 VP can be expressed in terms of the elastic constants and the density (ρ):

${\displaystyle V_{\mathrm {P} }={\sqrt {\frac {\lambda +2\mu }{\rho }}}={\sqrt {\frac {E(1-\sigma )}{\rho (1-2\sigma )(1+\sigma )}}}={\sqrt {\frac {K+{\frac {4}{3}}\mu }{\rho }}}}$

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

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