(1) |

berryman@sep.stanford.edu

## ABSTRACT
Since the work of Postma (1955) and Backus (1962), much is known
about elastic constants in vertical
transversely isotropic (VTI) media when the anisotropy is
due to fine layering of isotropic elastic materials.
I review earlier work and then show that the P-wave anisotropy parameter
c lies in the range
,when the layers are themselves
composed of isotropic elastic materials with Lamé constants
and and the vertical average of the layers is
symbolized by . The upper bound is true for all
finely layered media of this type, while the lower bound
is the best possible for fine layering with two constituents.
This lower bound corrects an error in Postma's (1955) paper on
two-component VTI media. The method used here shows in general terms
that the P-wave anisotropy parameter is smallest when the variation
in the layer Lamé parameter is large, independent of the
variation in the shear modulus . This result is therefore
important for applications to porous layers where the
effects of fluids influence only the Lamé constants,
not .Thus, the P-wave anisotropy parameter may be a useful hydrocarbon
indicator in some situations.
_{33} |

- INTRODUCTION
- WAVE PROPAGATION IN ANISOTROPIC ELASTIC MEDIA
- AVERAGING THIN LAYERS FOR LOW FREQUENCY BEHAVIOR
- REVIEW OF KNOWN INEQUALITIES FOR ELASTIC CONSTANTS
- RANGE OF THE ANISOTROPY PARAMETERS
- DISCUSSION
- ACKNOWLEDGMENTS
- REFERENCES
- About this document ...

11/11/1997