Mechanical Interactions Between Water and the Solid Earth: from Quasi-Static Geodetic Deformation to Dynamic Fault Slip

Citation

Larochelle, Stacy (2022) Mechanical Interactions Between Water and the Solid Earth: from Quasi-Static Geodetic Deformation to Dynamic Fault Slip. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2r5a-9277. https://resolver.caltech.edu/CaltechTHESIS:05302022-071239478

Abstract

Mechanical interactions between Earth's solid interior and its hydrosphere are central to many geophysical problems of crucial societal importance: Changing conditions in the global water cycle deform the solid Earth; the groundwater storage capacity of aquifer systems is controlled by its interaction with geological materials; and crustal water - either natural occurring or added through anthropogenic activities - affects earthquakes and fault slip processes. In this thesis, we investigate some of these interactions by harnessing recent developments in the fields of satellite geodesy, statistical data analysis and elastodynamic earthquake modelling. We start by developing a procedure to identify and extract seasonal deformation signals associated with hydrological loading of the solid Earth from geodetic time series in Chapter 1. In Chapters 2 and 3, we consider the examples of the Ozarks Plateau (central United States) and Sacramento Valley (California) to establish a methodology for characterizing poroelastic deformation arising from groundwater variations with space-based geodesy. Then, in Chapter 4, we develop a model to simulate fault slip due to crustal water injections and calibrate it against a well-instrumented field experiment on a natural fault. We conclude by deriving a theoretical understanding of these fault slip simulations by considering the simple case of a fixed-length pressurized zone in Chapter 5. Overall, our work provides key insights for extracting and using different sources of hydrogeodetic signals as well as for modeling and understanding fluid-induced fault slip processes, which is becoming increasingly important in a world faced with water scarcity, a changing climate and an increased reliance on groundwater and geoenergy resources.

Thesis Files