For a plane wave with horizontal slownesses p1 and p2 and frequency the displacement vector at some point in 3-space is given by,
The summation is over the six different wavetypes in the medium. These correspond to the six different roots of the sextic polynomial in p3. They have slownesses vectors , polarization vectors and amplitudes f(n). The vertical slownesses and displacement vectors are calculated by solving the Christoffel equation.
The strains in the medium are given by,
So the strains due to the nth wavetype are,
And the stresses are given by,