Comparison of observations (Data Source 4) of the amplitude of 2|$\psi$| and 4|$\psi$| components of Rayleigh and Love wave anisotropy (black 1|$\sigma$| error bars) from 8 to 50 s period at location (64|$^\circ$|N, 159|$^\circ$|W) in western Alaska with predictions using the elastic tensor models Model 1–Model 3 constructed here (Table 2). The blue dashed line is computed using Model 1 (based on Rayleigh wave 2|$\psi$| observations) and non-degenerate perturbation theory (Smith & Dahlen 1973; Montagner & Nataf 1986). The green dashed line is computed using Model 2 (based on Rayleigh wave 2|$\psi$| and Love wave 4|$\psi$| observations) and non-degenerate perturbation theory. The red line is computed using Model 3 (based on all observations) and using the quasi-degenerate theory we present here that includes Rayleigh-Love coupling. Using all data and the quasi-degenerate theory allows all data to be fit acceptably.