Modeling and imaging elastic waves in heterogeneous media

This thesis presents five studies that apply geophysical tools to image and interpret the heterogeneity of physical properties of the Earth at a range of spatial scales. Applications of the studies include resource exploration, environmental remediation, earthquake hazard assessment, and the evolution of Earth\u27s magnetic field from a process of compositional convection. The first study presents seismic waveform tomography, a technique that uses whole waveforms to image seismic velocity variations in two-dimensions. The second study applies wave-equation re-datuming through downward and upward continuation of surface recordings of ground penetrating radar (GPR) to image two-dimensional electromagnetic properties of the soil and weathered rock region near the surface. The third and fourth studies use a pseudospectral modeling technique of the seismic wavefield to simulate the effects of receiver-side heterogeneities on wavefronts at different angles and to study the strong ground motion in the Beijing area caused by a hypothetical magnitude 8.0 earthquake. The fifth study uses body wave data from arrays of seismic stations and Monte-Carlo simulations based on radiative transfer theory to study the solidification texture of the uppermost inner core.