From SEG Wiki
Jump to: navigation, search
This page contains changes which are not marked for translation.

Other languages:
English • ‎español

is one of the Thomsen anisotropic parameters [1]:

where indicate elements in the elastic stiffness matrix.

It is the most critical factor for transverse isotropy[2]. Several seismic expressions involve , such as the short-offset moveout correction to the vertical velocity,

where is the vertical velocity. For long offsets, another anisotropy parameter, (eta) measures the non-hyperbolic long-offset P-wave moveout [3]:

where is the far-offset anisotropy.


  1. Thomsen, Leon (1986). "Weak elastic anisotropy". GEOPHYSICS 51 (10): 1954–1966. doi:10.1190/1.1442051. PDF version.
  2. Thomsen, Leon (2002). Understanding Seismic Anisotropy in Exploration and Exploitation. Society of Exploration Geophysicists. doi:10.1190/1.9781560801986.
  3. Alkhalifah, Tariq; Tsvankin, Ilya (1995). "Velocity analysis for transversely isotropic media". GEOPHYSICS 60 (5): 1550–1566. doi:10.1190/1.1443888.PDF version.