Multiscale imaging of the Earth's interior with Receiver Function Scattering Kernels

Scattered wave imaging is an important tool for observing short-wavelength variations of the Earth’s structure that are not well resolved using tomographic methods. The analysis of mode conversions and other scattered phases resulting from teleseismic body waves, i.e. the receiver function method, has been used to image structures from the upper-crust to the mantle transition zone and beyond. Full waveform inversion (FWI) has recently emerged as a powerful technique that can be used to extract additional information from the recorded seismic wavefield. The FWI framework accounts for the full physics of seismic wave propagation, however, significant computational resources are typically required due to the demanding nature of solving the forward and adjoint simulations. This issue is particularly challenging for receiver function imaging because of the relatively high frequency of the seismic waves considered as well as the global scale of the forward problem. Several different approximation strategies have been proposed to reduce the computational burden of the FWI framework in this setting. For example, hybrid methods use a 3D regional scale model on the receiverside of the earth and the incoming teleseimic waves are approximated using a 1D reference model.