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Type of Document	Dissertation
Author	Xia, Kaiwen
URN	etd-02262005-161824
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-02262005-161824
Title	Laboratory investigations of earthquake dynamics
Degree	PhD
Option	Geophysics
Advisory Committee	Advisor Name Title Ares J. Rosakis Committee Chair Thomas H. Heaton Committee Co-Chair Guruswaminaidu Ravichandran Committee Member H. Kanamori Committee Member Jeroen Tromp Committee Member Nadia Lapusta Committee Member
Keywords	rupture transition earthquake dynamics laboratory earthqaukes spontaneous rupture supershear self-healing pulse
Date of Defense	2005-01-25
Availability	unrestricted
Abstract Earthquake represents one of most destructive geological hazards. In this thesis I will attempt to understand it through controlled laboratory experiments. The earthquake dynamic rupturing process itself is a complicated phenomenon, involving dynamic friction, wave propagation, and heat production. Because controlled experiments can produce results without assumptions needed in theoretical and numerical analysis, the experimental method is thus advantageous over theoretical and numerical methods. Our laboratory fault is composed of carefully cut photoelastic polymer plates (Homalite-100, Polycarbonate) held together by uniaxial compression. As a unique unit of the experimental design, a controlled exploding wire technique provides the triggering mechanism of laboratory earthquakes. Three important components of real earthquakes (i.e., pre-existing fault, tectonic loading, and triggering mechanism) correspond to and are simulated by frictional contact, uniaxial compression, and the exploding wire technique. Dynamic rupturing processes are visualized using the photoelastic method and are recorded via a high-speed camera. Our experimental methodology, which is full-field, in situ, and non-intrusive, has better control and diagnostic capacity compared to other existing experimental methods. Using this experimental approach, we have investigated several problems: dynamics of earthquake faulting occurring along homogeneous faults separating identical materials, earthquake faulting along inhomogeneous faults separating materials with different wave speeds, and earthquake faulting along faults with a finite low wave speed fault core. We have observed supershear ruptures, rupture speed transition, directionality of rupture in faults with a material contrast, self-healing slip pulses in faults with a finite core, crack-like to pulse-like rupture transition in faults with a finite core.
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