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What angle to choose? From the point of view of parsimony we can reduce the
number of variables from 13 to 12 by rotating our coordinate system around
the 3-axis by an angle = . This will
anihilate the two occurences of the *c*_{45} term.
| |
(4) |

Does this make sense physically? Yes. Since there is 2-fold symmetry, the three
waves propagating along the 3-axis have orthogonal directions of particle
motion, and those directions corresponding to the two pure shear waves define
two pseudo-symmetry axes. If the coordinate system is now aligned along these
axes, the c45 term disappears,

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** Up:** CANONICAL FORMS
** Previous:** Form Invariance under Rotation
Stanford Exploration Project

12/18/1997