This research is to perform a series of forward modelling experiments to study the effect of rough and anisotropic upper mantle structure on long-period seismic waveforms, and data experiments to infer the size and extent of such structure. This includes the synthesis of seismic anisotropy models derived from simple convective flows using the theory for lattice-preferred orientation. This will be combined with finite amplitude thermal convection models and free oscillation calculations to generate synthetic seismograms for anisotropic aspherical models derived from physical first principles. Objectives of the study include an understanding of the tradeoff between rough lateral structure and anelasticity in long-period surface-wave data, the tradeoff between isotropic and anisotropic mantle structure, and the bias introduced into smooth tomographic inversions by rough and/or anisotropic velocity structure.
