Seismic Wavefield Imaging of the Earth: the Regional, the Local, and the Remote

Citation

Castellanos, Jorge Alberto Castillo (2022) Seismic Wavefield Imaging of the Earth: the Regional, the Local, and the Remote. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/fm32-1t74. https://resolver.caltech.edu/CaltechTHESIS:07192021-182024547

Abstract

In this thesis, I use seismic wavefield methods to illuminate the interior structure and the dynamics of the Earth across different scales. First, I image the large-scale lithospheric structure at the eastern sector of the Trans-Mexican Volcanic Belt to constrain on the transition from flat to steeper subduction in central Mexico. Then, I move to a regional scale and image the dynamics of the Wallowa Mountain block in northeastern Oregon, where mantle-based stresses appear to have played an essential role in shaping the crustal structure. With the findings of this investigation, I was able to illuminate a deformation mechanism of mantle origin, which I also use here to explain other near-surface processes in different parts of the North America continent. After, I move to a local scale, where I use dense oil-industry instrumentation to image the sub-kilometer crustal structure of Long Beach, California. In the first part of this investigation, I use noise-derived surface waves to create a high-resolution shear wave velocity model of the first kilometer of the crust, which I use to numerically determine the variability in the expected ground shaking intensity of the area. In the second part, I move past the traditional surface wave analysis and use the body wave portion of the noise-derived Green's functions to create a high-resolution compressional wave velocity model beneath one of the surveys. Finally, I present a waveform-based method of analysis that shows great promise as a new way of investigating the seismic behavior and the physical conditions of isolated marine environments.

Thesis Files