One important question in diffractional seismic tomography is the significance of finite-frequency effects. Based on wave propagation simulations in a range of Earth models, We showed that diffractional effects are scale-dependent. For example, in global models developed based on ray theory, small-scale heterogeneities are often damped due to the inconsistency between data and theory. Therefore, finite-frequency effects are not significant when ray-theoretical global models are used in wave propagation simulations.

The scale-dependence of finite-frequency effects

We compared traditional ray-theoretical surface-wave tomography with finite-frequency tomography based on inversions of fundamental-mode dispersion measurements and showed that small-scale wavespeed anomalies are better resolved in finite-frequency tomographic models as wave front healing effects are properly taken into account.

Finite-frequency tomography fit data better than ray theory tomography

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Ying Zhou June 2012