Accelerograms from the IDA network have been processed to obtain 2193 multiplet locations (apparent centre frequencies) for the fundamental spheroidal modes 0S5–0S43-. Great circles connecting the 72 source–receiver pairs provide a good sampling of the Earth's major tectonic regions, although the distribution of their poles is biased to high latitudes. Estimates of the degenerate eigenfrequencies, corrected for this bias, are significantly greater than Gilbert & Dziewonski's values for l≥ 10. The differences between the observed degenerate eigenfrequencies and those calculated for radial reference models display jumps between 0S10 and 0S11 and between 0S18 and 0S19 that cannot be explained by radial Earth structure or random noise processes; we attribute these jumps to Coriolis coupling between 0Sl and 0Tl+1. The RMS relative scatter in the multiplet location measurements, corrected for noise, decreases from about 1.4 × 10−3 for l≤ 10 to about 0.8 × 10−3 for l≃ 40 and is evidently caused by aspherical heterogeneities in the Earth's crust and mantle. Corrections for hydrostatic ellipticity significantly reduce the scatter for l < 17, but the reductions at higher angular orders are less than expected; in fact, ellipticity corrections actually increase the scatter for 19 ≤l≤ 27. Implied by this observation is some kind of aspherical heterogeneity whose effects on fundamental-mode multiplet locations above l≃ 20 are negatively correlated with the ellipticity perturbation. Using high-frequency approximations we have inverted the multiplet location data for the local eigenfrequency perturbations, δωlocal, associated with the six major tectonic provinces in Jordan's regionalization. The local eigenfrequencies within the ocean basins increase systematically with crustal age, in agreement with dispersion measurements at higher frequencies, and those within the continents are most positive for Precambrian cratons. The δωlocal values for the cratons are generally greater than those for average ocean basin and comparable to those found in older oceanic regions. The local eigenfrequency variations decrease in absolute magnitude with decreasing angular order number, but they remain coherent to frequencies as low as 2 mHz (0S12). We present evidence which suggests that non-asymptotic effects contribute appreciably to the data variance at low frequencies and thus may corrupt the local eigenfrequency estimates derived from the asymptotic theory.