This animation illustrates so-called Shear-Wave Splitting (SWS) which can occur when a seismic shear-wave travels in an anisotropic medium. Here we are looking at a horizontal transverse isotropic (HTI) medium with fast and a slow vertical planes. When the initial polarization of the seismic wave is not alligned with one of these two planes, it will split into a fast traveling wave polarized in the fast plane f and into a slow traveling wave polarized in the slow plane s. This can be observed in the animation below.
The animation was created using TikZ. The code is contained in the file animateSWS.tex which creates a PDF file.
To convert the PDF file to an animated GIF file, I used:
convert -density 400 -delay 13 -loop 0 -background white -alpha remove animateSWS.pdf images/SWS.gif