Seismic Wave Demos…
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Seismic Wave Demonstrations and Animations 1
L. Braile, Purdue University
braile@purdue.edu, www.eas.purdue.edu/~braile December, 2004
1. Introduction: Seismic wave animations are used to illustrate different types of wave propagation through elastic materials. Animations are provided to view wave propagation in a 3dimensional solid for Compressional (P), Shear (S), Rayleigh (R) and Love (L) waves. Wave characteristics and particle motions of these wave types can be easily illustrated using the seismic wave animations. 2. Seismic Waves: The main seismic wave types are Compressional (P), Shear (S), Rayleigh (R) and Love (L) waves. P and S waves are often called body waves because they propagate outward in all directions from a source (such as an earthquake) and travel through the interior of the Earth. In the animations shown here, the P and S waves are shown propagating horizontally, parallel to the Earth's surface. Love and Rayleigh waves are surface waves and propagate approximately parallel to the Earth's surface. Although surface wave motion penetrates to significant depth in the Earth, these types of waves do not propagate directly through the Earth's interior. Descriptions of wave characteristics and particle motions for the four wave types are given in Table 1. Further information on seismic waves, wave propagation in the Earth, and visualizations of seismic waves can be found in Bolt (1993, p. 27 and 37; 2004, p. 21) and Shearer (1999, p. 32 and 152). Information on teaching about seismic waves and demonstrations of seismic wave characteristics using a slinky are provided at: http://www.eas.purdue.edu/~braile/edumod/slinky/slinky.htm. A four-page teacher's guide about seismic waves and the slinky is available as an MS Word document at: http://www.eas.purdue.edu/~braile/edumod/slinky/slinky4.doc, or, as an html file at: http://www.eas.purdue.edu/~braile/edumod/slinky/slinky4.htm.
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Last modified January 6, 2005

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