## Determination of the reference symmetry axis
of a generally anisotropic medium
which is approximately transversely isotropic

**Ludek Klimes**
### Summary

For a given stiffness tensor (tensor of elastic moduli) of
a generally anisotropic medium, we estimate to which extent is
the medium transversely isotropic and determine the direction
of its reference symmetry axis in terms of the reference symmetry
vector. If the medium is exactly transversely isotropic, we obtain
its symmetry axis. We can also calculate the first-order and
second-order spatial derivatives of the reference symmetry vector.
The proposed method is illustrated in various transversely isotropic
and approximately transversely isotropic velocity models.

### Keywords

Elastic anisotropy, stiffness tensor, elastic moduli,
transverse isotropy, approximate transverse isotropy,
reference symmetry axis.

### Whole paper

The paper is available in
PDF (93 kB).

*Seismic Waves in Complex 3-D Structures*, **25** (2015), 177-185
(ISSN 2336-3827, online at http://sw3d.cz).