UC Berkeley

This dissertation delves into the dynamics of Earth's interior across varying spatial and temporal scales, using innovative techniques to advance our understanding of the intricate processes that govern our planet's evolution and structural behavior. It integrates diverse methodologies and datasets within the realm of geophysics, at the intersection of seismology, geodesy, and geodynamics. Following a concise introduction, the subsequent two chapters focus on enhancing computational methods for Earth imaging through seismic tomography. Their objective is to bridge global and regional scales via "box tomography", which optimizes computation efficiency for the imaging of target regions in the context of Full-Waveform Inversion. Furthermore, a versatile merging package is introduced, designed to combine multi-scale, multi-resolution georeferenced datasets, which facilitates high-resolution simulations while preserving the global contextual integrity. The exploration of rotational dynamics follows, investigating low-frequency length-of-day oscillations on a pluriannual timescale. These oscillations offer potential insights into the buoyancy structure of the lower mantle. The final chapter expands seismic studies to impact-induced seismic waves, probing potential links between asteroid collisions and volcanic eruptions, notably during the Cretaceous–Paleogene mass extinction. Through systematic sensitivity analyses, computational efforts, and geophysics-based constraints, the dissertation yields insights into Earth's intricate processes, with implications spanning the fields of seismology and geodynamics.