## Estimativa de anisotropia local de dados de onda P
em experimentos de VSP multiazimutal

**Adriano C. R. Barreto**,
**Raiza de N. A. Macambira**,
**Ellen N. S. Gomes** e
**Ivan Psencik**
### Summary

Inversion scheme for the local determination of
anisotropy from P-wave data obtained during a multiazimuth
multiple-source VSP experiment is studied.
The inversion is based on an approximate formula
relating linearly weakly anisotropic (WA) parameters
describing the medium at a receiver and the vertical
components of slowness vectors and complete
polarization vectors measured at the same point. The
optimum choices of the reference isotropic medium
and of the unit normal of the wave in the reference
medium are presented. Efficiency of the inversion
scheme, stability and sensitivity of its results with
respect to varying number of profiles, types of used
waves (direct and/or reflected) and noise levels are
analyzed. It is also shown that although only P-wave
data are used, it is possible to estimate the orientation
of the axis of symmetry of a TI medium from estimated
parameters.

### Whole paper

The paper is available in
PDF (2584 kB).

In: Seismic Waves in Complex 3-D Structures, Report 21,
pp. 63-68, Dep. Geophys., Charles Univ., Prague, 2011.