Imaging global mantle discontinuities: a test using full-waveforms and adjoint kernels

SUMMARY We present a novel approach for imaging global mantle discontinuities based on full-waveform inversion (FWI). Over the past decades, extensive research has been done at approximately 400 and 670 km depth. Accurate knowledge of their topography can put strong constraints thermal compositional variations hence geodynamic modelling. So far, however, there is little consensus topography. an adjoint tomography, which advantage that Fréchet derivatives measurements, to be inverted for, are fully consistent. Rather than working with real data, we focus synthetic tests, where answer known in order able evaluate performance developed method. All calculations community code SPECFEM3D_GLOBE. generate data fixed 1-D or 3-D elastic background models velocity. Our ‘data’ contain along discontinuities. To investigate approach, perform several tests: (i) In situation know model 3-D, recover target fast accurately; (ii) The exact misfit not great importance here, except terms convergence speed, similar different inverse algorithm (iii) known, markedly slower, but reasonable towards correct discontinuity It noted our test idealized situation, uncertainty inferred bound larger. However, use consistent kernels seems pay off might improve nature workflow could incorporated future FWI adequately infer boundary interface