.3-that Love wave and Rayleigh wave data were inconsistent unless SH> SV in at least the upper 125 km. He also believed that anisotropy might be present below 250 km. Schlue and Knopofi [1977] found that the LVZ was anisotropic but the crust and lid could be modeled as isotropic, Their LVZ extends front 180 km to the bottom of the lid (15 km -115 km depending on age). They comment that the observed P. velocity can be a;tiAained by a thin sub-moho layer that would not be resolved by their data. Schlue and Knopofl [ 1978] included anisotropy in the LVZ for a suite of calculated models. Yu and Mitchell [1979] and Mitchell and Yu [1980] find anisotropy predominantly in the lithosphere and possibly in the LVZ. These studies have found that lithosphere thickness and lithosphere velocity generally increase with age, except Schlue and Knopofi [1977] who constrained their velocities to remain constant with age. The differences in the depth where anisotropy is located in these studies can be attributed to differences in the assumptions, the constraints, the inversion methods, or to some systematic.The most serious source of systematic error is the separate isotropic inversion of Love and ?ayleigh waves to give an anisotropic structure. The studies discussed above are almost all based on pseudo-isotropic inversions that determine SV velocity from isotropic Rayleigh wave inversion and SH velocity from isotropic Love wave inversion. The differences between the two models are then used as a measure of the anisotropy. Separate isotropic inversions make no allowance for P-wave anisotropy, and include neither the effects of SV velocity on Love wave velocities nor the effect of changes in PV, PH, and SH velocities on Rayleigh waves. Thus, the procedure of using separate isotropic inversions is useful only to indicate the probable presence of anisotropy, or to calculate responses for propagation in planes perpendicular to the symmetry axis in a transversely isotropic medium [Crampin, 1976]. Some studies [Yu and Mitchell,