Encyclopedia of Natural Hazards

2013 Edition
| Editors: Peter T. Bobrowsky

Secondary Wave (S-Wave)

  • Allison BentEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4399-4_311

Synonyms

S wave; Shear wave; Transverse wave

Definition

Secondary waves are elastic shear waves that travel through the Earth.

Discussion

S waves are seismic body waves meaning they travel through the Earth’s interior. Their velocity is slower than that of P waves, and they are normally the second major phase to be observed on a seismogram, and are therefore also referred to as secondary waves. In the Earth’s crust, S wave velocities are typically 3–4 km/s. S waves are usually larger in amplitude than P waves and may cause strong shaking and/or damage. The particle motion associated with S waves is perpendicular to the direction of propagation. S waves can be subdivided into two groups: SV waves, which are recorded by seismographs on the vertical and radial components; and SH waves, which appear on the tangential component. S waves cannot propagate through liquids or gases, the knowledge of which helped lead to the discovery that the outer core was liquid.

Cross-references

 Body Wave

 

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Bibliography

  1. Aki, K., and Richards, P. G., 1980. Quantitative Seismology Theory and Methods. San Francisco: W. H. Freeman.Google Scholar
  2. Bolt, B. A., 1993. Earthquakes. New York: W. H. Freeman.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Geological Survey of CanadaNatural Resources CanadaOttawaCanada