Title

Modeling and imaging elastic waves in heterogeneous media

Date of Completion

January 2010

Keywords

Geophysics

Degree

Ph.D.

Abstract

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's 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. ^