For a plane wave with horizontal slownesses *p _{1}* and

The summation is over the six different wavetypes in the
medium. These correspond to the six different roots of the sextic polynomial
in *p _{3}*. They have slownesses vectors ,
polarization vectors and amplitudes

The strains in the medium are given by,

So the strains due to the *n*^{th} wavetype are,

And the stresses are given by,

12/18/1997