Three-dimensional deformation and stress models of the Death Valley and San Andreas Fault Zones.

摘要

Crustal deformation studies of tectonic motions have been the topic of many scientific investigations, as they can provide critical information about how tectonic structures shape and deform the Earth. While crustal deformation studies using observational data alone can provide a great deal of information about how the Earth is presently deforming, it is standard practice to implement mathematical and physics-based models to investigate the underlying causes of deformation in the crust. These models, constrained by geological, geodetic and seismic data, have successfully contributed key constraints of ongoing deformation processes and have provided predictions of past and future tectonic behavior of the Earth. One of the most popular regions of study on Earth is the San Andreas Fault System (SAFS), as it provides an ideal environment for investigating the deformation caused by a major continental transform boundary. Furthermore, the Death Valley Fault Zone (DVFZ) is an ideal area to study large-scale crustal deformation due to its well-exposed features related to progressive extensional deformation.;This dissertation presents new information about the deformation, stress accumulation rates, and strain rates taking place in the DVFZ and SAFS using three-dimensional (3-D) crustal deformation models. Chapter 1 provides the background and motivation of the modeling work applied to both fault systems. Chapter 2 provides the results obtained from applying a 3-D semi-analytic viscoelastic model constrained by GPS measurements to explore the kinematics and stress accumulation in the DVFZ. Chapter 3 analyzes the influence of intrusions on the motion and deformation of the DVFZ through a finite difference modeling approach. Chapter 4 explores the strain rate distribution within the SAFS, assuming a dipping fault geometry for its southern segments, utilizing a modified 3-D semi-analytic viscoelastic model. Lastly, Chapter 5 gives a description of the future work that may be followed based on the results obtained from this dissertation work.